HomeMy WebLinkAbout1.02 General Application Materials_PartCTitle:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPF8.11.2022RPFRiflePit-FloodplainABF3118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com Graphic ScaleIn U.S. Feet : 1" = 1000'0500 10002000IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)FloodplainVicinity MapRifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPFRPFRiflePit-ExhibitsABF4118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com Graphic ScaleIn U.S. Feet : 1" = 200'0 100 200400IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Existing ConditionsRifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPFRPFRiflePit-DesignABF5118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com Graphic ScaleIn U.S. Feet : 1" = 120'0 60 120240IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Reclamation PlanRifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPFRPFRiflePit-ExhibitsABF6118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com Graphic ScaleIn U.S. Feet : 1" = 200'0 100 200400IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Mining ProgressionExhibit - 30%Rifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPFRPFRiflePit-ExhibitsABF7118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com Graphic ScaleIn U.S. Feet : 1" = 200'0 100 200400IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Mining ProgressionExhibit - 60%Rifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPFRPFRiflePit-ExhibitsABF8118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com Graphic ScaleIn U.S. Feet : 1" = 200'0 100 200400IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Mining ProgressionExhibit - 100%Rifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPFRPFRiflePit-DesignABF9118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com Graphic ScaleIn U.S. Feet : 1" = 120'0 60 120240IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Erosion Control PlanRifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPF08/11/2022RPFRiflePit-DetailsABF10118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Erosion Control DetailsRifle Pit Gravel Pit #1 08/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPF8.11.2022RPFRiflePit-DetailsABF11118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Typical Mineral StrataRifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPFRPFRiflePit-DetailsABF12118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Typical GravelProcessing LayoutRifle Pit Gravel Pit #108/11/202208/11/2022
Title:Revision#Dwg No.Job No.Drawn by:Date:File:PE:QC:Date By:
Project Milestone:Of :2019-341.002RPFRPFRiflePit-DetailsABF13118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
IHC-Scott, Inc. dba
Scott Contracting, Inc. 13Permit Set (Not For Construction)Spill Prevention Control& Containment (SPCC)DetailRifle Pit Gravel Pit #108/11/202208/11/2022
Revised Floodplain Development Permit Narrative for Rifle Pit #1 August 2022
B
Attachment B
Floodplain Engineering Report
IHC -Scott
Floodplain Engineering Report
May 2022
Prepared by
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004
Floodplain Engineering Report May 2022
Floodplain Engineering Report
IHC-SCOTT
Prepared By
Richard (Chip) Fisher, P.E.
QC Reviewed By
Angela B. Fowler, P.E.
SGM Project 2019-341.002
Floodplain Engineering Report May 2022
i
Table of Contents
1.0 Project Description ........................................................................................................ 1
2.0 HEC-RAS Model Inputs .................................................................................................. 1
2.1 Flow and Boundary Conditions ................................................................................ 1
2.2 Existing Conditions Geometry ................................................................................... 1
2.3 Proposed Conditions Geometry............................................................................... 1
3.0 HEC-RAS Model Results ................................................................................................. 4
4.0 HEC-RAS Floodway Encroachment ............................................................................. 5
5.0 No-Rise Certification ..................................................................................................... 7
6.0 Engineer’s Contact Information .................................................................................. 7
Appendix A .............................................................................................................................. A
Floodplain Engineering Report May 2022
1
1.0 Project Description
IHC Scott, Inc. (dba IHC Scott Contracting, Inc.) (Scott), a construction and gravel
mining firm based in Centennial, CO, purchased a 58.7-acre parcel (Property) located in
unincorporated Rifle, CO (Garfield County Parcel No. 217-908-300-103). The proposed
Rifle Pit #1 is just north of Interstate 70 (I-70), roughly 1-mile northeast of the Rifle
Airport. Scott retained SGM to prepare a Floodplain Development Permit application for
the proposed 19.63-acre gravel mining project known as Rifle Pit #1. Development of the
site will entail mining of sand and gravel. There are no residential construction activities
planned for the site. An estimated 100-year floodplain delineation, base flood elevation,
and floodway delineation were determined by SGM to quantify flood impacts of the Rifle
Pit #1 project on neighboring properties. The effective FEMA study area (Panel
0802051360B dated 12/15/1977) covering the project area shows a Zone A floodplain,
which is an unstudied approximate floodplain delineation. The 100-year flood event of
the Colorado River was modeled to determine a base flood elevation and floodplain
delineation. This narrative summarizes the results of the HEC-RAS model developed to
predict the extents of the 100-year floodplain and any impacts to the base flood (BFE)
resulting from the proposed Rifle Pit #1 project.
2.0 HEC-RAS Model Inputs
2.1 Flow and Boundary Conditions
The CWCB analyzed hydrology of the Colorado River Basin and determined that the
100-year (1%) flow in the vicinity of the Rifle Pit #1 project area is projected to be
34,900 𝑐𝑓𝑠 (cubic feet per second) which was used as the steady-state flow in both
existing and proposed conditions of the model. The boundary condition for both existing
and proposed conditions was set to a Normal Depth at the downstream cross-section
(River Station 175063.0) with a slope (𝑠) of 0.225%, as determined from LiDAR
elevations.
2.2 Existing Conditions Geometry
Existing conditions were derived from Garfield County LiDAR topography. The HEC-
RAS existing condition geometry (i.e., cross-sections, riverbank locations, ineffective
flow areas, and river thalweg) is shown in Figure 1. An existing gravel pit, just west of the
Rifle Pit #1 project area, was modeled as an obstruction after analyzing aerial imagery
that shows the pit does not fill with water.
2.3 Proposed Conditions Geometry
Proposed conditions were developed in AutoCAD to reflect the mining operation phase
of the project and inserted in the LiDAR surface to create a hybrid surface. The HEC-
RAS proposed condition geometry is shown in Figure 2. The Rifle Pit #1 project was
modeled as an obstruction within the perimeter berm to prevent flow from entering the pit
and erroneously decreasing the WSE in the model. The engineering drawings dated
April 14, 2022, show a mining plan that covers much less area inside the Property than
the proposed conditions surface used in the HEC-RAS model. As such, the HEC-RAS
model results are more conservative (i.e., showing more disturbance inside the
floodplain) and are valid for the current mining plan.
Floodplain Engineering Report May 2022
2
Figure 1. Map showing LiDAR topography of the Existing Condition and the model cross sections (light green lines), river thalweg (blu e line), and the left
and right banks of the Colorado River (red dots).
Floodplain Engineering Report May 2022
3
Figure 2. Map showing hybrid AutoCAD/LiDAR topography of the Proposed Condition and the model cross sections (light green lines), river thalweg (blue
line) and the left and right banks of the river (red dots).
Floodplain Engineering Report May 2022
4
3.0 HEC-RAS Model Results
A hydraulic model was developed using HEC-RAS to simulate flooding effects during the
100-year flood event both before and after the proposed mining operation. Hydraulic
stresses were analyzed to determine appropriate erosion control and structural
characteristics of the earthen berm to withstand flood conditions. The difference between
the existing and proposed water surface elevations (WSE) was computed as the rise, in
units of feet. A summary of the HEC-RAS model results provided in Table 1.
Table 1. Summary of HEC-RAS model results of the existing and proposed water surface elevations (WSE)
and the computed rise (i.e., difference between existing and proposed WSE) at each model cross -section,
denoted by its station along the river thalweg.
Summary of Water Surface Elevation Rise
River Cross-Section
(ft)
Existing WSE
(ft)
Proposed WSE
(ft)
Rise
(ft)
30902.14 5412.3 5412.3 0.0
29650.64 5409.4 5409.4 0.0
29500 Bridge Bridge N/A
29427.62 5406.2 5406.2 0.0
27494.84 5400.4 5400.4 0.0
26255.61 5397.1 5397.1 0.0
25219.46 5393.1 5393.1 0.0
24101.01 5389.9 5389.9 0.0
22688.22 5385.4 5385.4 0.0
20730.67 5379.1 5379.1 0.0
19398.23 5375.5 5375.5 0.0
17708.26 5371.8 5371.8 0.0
15834.35 5365.6 5365.6 0.0
13915.69 5359.6 5359.6 0.0
In the proposed condition geometry (Error! Reference source not found.), cross-sections 22688.22 and
0730.67 intersect the proposed Rifle Pit #1 (earthen berm and mining pit). Velocity, hydraulic depth, and
shear stress were computed at these cross sections as well as the nearest upstream and downstream cross
sections.
Table 2 below summarizes the model results of the cross-sections that closely capture the
proposed Rifle Pit #1 topography. Appendix A provides more detailed model results for
each cross-section.
Table 2. HEC-RAS model results of velocity, hydraulic depth, and shear stress of the left-over bank regions
in the model cross-sections nearest the proposed Rifle Pit #1 project area.
Velocity, Hydraulic Depth, and Shear Stress
River Cross-Section
(ft)
Velocity
(ft/s)
Hydraulic Depth
(ft)
Shear Stress
(ft)
24101.01 2.0 2.8 0.4
22688.22† 2.8 2.6 0.7
20730.67† 2.7 3.2 0.6
19398.23 2.4 3.5 0.5
† Cross-sections intersecting the proposed Rifle Pit #1 project area.
Floodplain Engineering Report May 2022
5
4.0 HEC-RAS Floodway Encroachment
SGM used the same HEC-RAS model to implement an encroachment analysis, where
the effective flow area in the model has been incrementally decreased until the predicted
water surface elevations at each modeled cross-section increased by 0.5 feet (known as
the predicted surcharge), as described in Rule 8 of 2 CCR 408-1.
An encroachment analysis was used to estimate the floodway, using an iterative process
of decreasing the effective flow area at each modeled cross-section by starting
downstream at River Station 13915.69 and moving upstream. Some cross-sections
showed no change in water surface elevation (WSE), so the floodway delineation is
approximated as the stream bank at those cross-sections. Left and Right Offsets for the
floodway delineations are summarized below in Error! Reference source not found. and o
verlaid with the model geometry and topography in Figure 3.
Table 3. Summary of left and right offset stations for the floodway encroachment at each model cross-
section, as well as the predicted surcharge (feet), or the artificial rise in WSE due to encroachment of the
banks toward the river thalweg.
Floodway Encroachment Analysis Summary
River Cross-
Section
(ft)
Left Floodway
Station
(ft)
Left Bank
Station
(ft)
Right Bank
Station
(ft)
Right Floodway
Station
(ft)
Predicted
Surcharge
(ft)
30902.14 1597.59 1956.95 2317.12 2421.92 0.50
29650.64 326.82 336.82 798.40 808.41 0.00
29500 Bridge Bridge Bridge Bridge 0.00
29427.62 356.90 366.90 982.50 992.50 0.50
27494.84 731.93 1401.12 2094.84 2104.84 0.50
26255.61 950.92 1974.18 2547.44 2557.44 0.50
25219.46 1391.78 1974.18 2547.44 3153.62 0.28
24101.01 1590.08 2483.80 2953.56 3982.04 0.50
22688.22 2402.02 3158.24 3981.04 5018.53 0.50
20730.67 3270.79 4559.40 5003.53 5510.56 0.50
19398.23 3012.35 4964.81 5448.56 5944.03 0.50
17708.26 3589.25 5386.70 5984.03 5751.30 0.50
15834.35 3052.93 3062.93 4872.42 4882.42 -0.10
13915.69 1935.13 1945.13 3731.21 3741.21 0.50
Floodplain Engineering Report May 2022
6
Figure 3. Encroachment Analysis results map showing the floodway (pink line) and the floodplain (black) delineations.
Floodplain Engineering Report May 2022
7
5.0 No-Rise Certification
The proposed Rifle Pit #1 project will result in no rise to the WSE during the 100-yr flood
known as the base flood elevation (BFE). Furthermore, the proposed Rifle Pit #1 is also
outside of the floodway, which satisfies requirements of Grand County Land Use
Development Code (LUDC) Sections 3-301 and 4-203 (O). An earthen berm built at 2H:1V
slope to a height of 5-ft above ground elevation, seeded with native vegetation blend and
stabilized with erosion control blankets surrounding the proposed Rifle Pit #1 project area
will withstand the hydrostatic and hydrodynamic stresses during the 100-yr flood.
6.0 Engineer’s Contact Information
If you have any questions regarding this Floodplain Engineering Report for the Rifle Pit
#1 project, contact Chip Fisher at (303) 746-2549 and chipf@sgm-inc.com.
Sincerely,
Richard (Chip) Fisher, P.E.
Floodplain Engineering Report May 2022
A
Appendix A
Detailed Model Results
HEC-RAS Plan: Existing2 River: Colorado River Reach: Site 1 Profile: PF 1
Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft)(ft/ft) (ft/s) (sq ft) (ft)
Site 1 30902.14 PF 1 34900.0 5404.0 5412.3 5412.5 0.0 4.99 14256.0 2639.3 0.31
Site 1 29650.64 PF 1 34900.0 5400.0 5409.4 5406.4 5410.7 0.0 9.17 3806.1 431.7 0.54
Site 1 29500 Bridge
Site 1 29427.62 PF 1 34900.0 5400.0 5406.2 5406.2 5409.1 0.0 13.76 2536.7 435.3 1.00
Site 1 27494.84 PF 1 34900.0 5394.0 5400.4 5400.8 0.0 5.83 9099.6 1989.1 0.42
Site 1 26255.61 PF 1 34900.0 5390.5 5397.1 5397.8 0.0 7.92 7603.5 2397.0 0.60
Site 1 25219.46 PF 1 34900.0 5388.0 5393.1 5393.6 0.0 7.78 8065.2 2482.7 0.64
Site 1 24101.01 PF 1 34900.0 5384.0 5389.9 5390.2 0.0 5.54 10742.4 3287.2 0.45
Site 1 22688.22 PF 1 34900.0 5380.8 5385.4 5385.8 0.0 6.93 11072.7 4549.1 0.63
Site 1 20730.67 PF 1 34900.0 5374.9 5379.1 5379.3 0.0 5.19 11372.2 3465.4 0.49
Site 1 19398.23 PF 1 34900.0 5372.0 5375.5 5375.7 0.0 4.14 13616.5 4038.0 0.43
Site 1 17708.26 PF 1 34900.0 5366.0 5371.8 5372.0 0.0 4.90 10922.9 2547.9 0.44
Site 1 15834.35 PF 1 34900.0 5361.9 5365.6 5366.1 0.0 5.93 6972.2 2816.5 0.61
Site 1 13915.69 PF 1 34900.0 5353.8 5359.6 5358.1 5359.9 0.0 4.86 8147.4 2500.3 0.44
Floodplain Engineering Report - Appendix A May 2022
A-1
Plan: Existing2 Colorado River Site 1 RS: 30902.14 Profile: PF 1
E.G. Elev (ft)5412.53 Element Left OB Channel Right OB
Vel Head (ft)0.19 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5412.34 Reach Len. (ft)1356.00 1251.50 946.00
Crit W.S. (ft) Flow Area (sq ft)7438.50 2950.46 3866.98
E.G. Slope (ft/ft) 0.000837 Area (sq ft)7438.50 2950.46 3866.98
Q Total (cfs)34900.00 Flow (cfs)13152.40 14721.71 7025.89
Top Width (ft)2639.26 Top Width (ft)1521.88 360.17 757.21
Vel Total (ft/s)2.45 Avg. Vel. (ft/s)1.77 4.99 1.82
Max Chl Dpth (ft)8.34 Hydr. Depth (ft)4.89 8.19 5.11
Conv. Total (cfs) 1206009.0 Conv. (cfs)454496.1 508725.5 242787.5
Length Wtd. (ft)1240.44 Wetted Per. (ft)1523.23 360.49 760.21
Min Ch El (ft)5404.00 Shear (lb/sq ft)0.26 0.43 0.27
Alpha 2.06 Stream Power (lb/ft s)0.45 2.14 0.48
Frctn Loss (ft)1.69 Cum Volume (acre-ft) 2259.83 1241.74 88.17
C & E Loss (ft)0.11 Cum SA (acres)748.32 300.04 20.11
Plan: Existing2 Colorado River Site 1 RS: 29650.64 Profile: PF 1
E.G. Elev (ft)5410.73 Element Left OB Channel Right OB
Vel Head (ft)1.31 Wt. n-Val. 0.035
W.S. Elev (ft)5409.43 Reach Len. (ft)10.00 10.00 10.00
Crit W.S. (ft)5406.35 Flow Area (sq ft) 3806.14
E.G. Slope (ft/ft) 0.002587 Area (sq ft) 3806.14
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)431.69 Top Width (ft) 431.69
Vel Total (ft/s)9.17 Avg. Vel. (ft/s) 9.17
Max Chl Dpth (ft)9.42 Hydr. Depth (ft) 8.82
Conv. Total (cfs) 686135.0 Conv. (cfs) 686135.0
Length Wtd. (ft)10.00 Wetted Per. (ft) 435.00
Min Ch El (ft)5400.00 Shear (lb/sq ft) 1.41
Alpha 1.00 Stream Power (lb/ft s) 12.96
Frctn Loss (ft)0.03 Cum Volume (acre-ft) 2144.05 1144.68 46.18
C & E Loss (ft)0.05 Cum SA (acres)724.64 288.67 11.89
Plan: Existing2 Colorado River Site 1 RS: 29500 BR U Profile: PF 1
E.G. Elev (ft)5410.65 Element Left OB Channel Right OB
Vel Head (ft)1.47 Wt. n-Val. 0.035
W.S. Elev (ft)5409.19 Reach Len. (ft)195.00 195.00 195.00
Crit W.S. (ft)5406.53 Flow Area (sq ft) 3593.16
E.G. Slope (ft/ft) 0.003544 Area (sq ft) 3593.16
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)418.62 Top Width (ft) 418.62
Vel Total (ft/s)9.71 Avg. Vel. (ft/s) 9.71
Max Chl Dpth (ft)9.19 Hydr. Depth (ft) 8.58
Conv. Total (cfs) 586246.7 Conv. (cfs) 586246.7
Length Wtd. (ft)195.00 Wetted Per. (ft) 476.94
Min Ch El (ft)5400.00 Shear (lb/sq ft) 1.67
Alpha 1.00 Stream Power (lb/ft s) 16.19
Frctn Loss (ft)0.93 Cum Volume (acre-ft) 2144.05 1143.83 46.18
C & E Loss (ft)0.21 Cum SA (acres)724.64 288.57 11.89
Floodplain Engineering Report - Appendix A May 2022
A-2
Plan: Existing2 Colorado River Site 1 RS: 29500 BR D Profile: PF 1
E.G. Elev (ft)5409.51 Element Left OB Channel Right OB
Vel Head (ft)2.16 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5407.36 Reach Len. (ft)18.02 18.02 18.02
Crit W.S. (ft)5406.34 Flow Area (sq ft)2.21 2963.34
E.G. Slope (ft/ft) 0.006786 Area (sq ft)2.21 2963.34
Q Total (cfs)34900.00 Flow (cfs)0.77 34899.23
Top Width (ft)461.64 Top Width (ft)28.22 433.42
Vel Total (ft/s)11.77 Avg. Vel. (ft/s)0.35 11.78
Max Chl Dpth (ft)7.36 Hydr. Depth (ft)0.08 6.84
Conv. Total (cfs) 423673.1 Conv. (cfs)9.3 423663.8
Length Wtd. (ft)18.02 Wetted Per. (ft)28.41 479.53
Min Ch El (ft)5400.00 Shear (lb/sq ft)0.03 2.62
Alpha 1.00 Stream Power (lb/ft s)0.01 30.83
Frctn Loss (ft)0.15 Cum Volume (acre-ft) 2144.04 1129.16 46.18
C & E Loss (ft)0.24 Cum SA (acres)724.57 286.66 11.89
Plan: Existing2 Colorado River Site 1 RS: 29427.62 Profile: PF 1
E.G. Elev (ft)5409.13 Element Left OB Channel Right OB
Vel Head (ft)2.94 Wt. n-Val. 0.035
W.S. Elev (ft)5406.19 Reach Len. (ft)1192.00 1932.78 2126.00
Crit W.S. (ft)5406.19 Flow Area (sq ft) 2536.74
E.G. Slope (ft/ft) 0.010064 Area (sq ft) 2536.74
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)435.26 Top Width (ft) 435.26
Vel Total (ft/s)13.76 Avg. Vel. (ft/s) 13.76
Max Chl Dpth (ft)6.19 Hydr. Depth (ft) 5.83
Conv. Total (cfs) 347881.4 Conv. (cfs) 347881.4
Length Wtd. (ft) 1821.69 Wetted Per. (ft) 436.95
Min Ch El (ft)5400.00 Shear (lb/sq ft) 3.65
Alpha 1.00 Stream Power (lb/ft s) 50.18
Frctn Loss (ft)6.26 Cum Volume (acre-ft) 2144.04 1128.02 46.18
C & E Loss (ft)1.28 Cum SA (acres)724.57 286.48 11.89
Plan: Existing2 Colorado River Site 1 RS: 27494.84 Profile: PF 1
E.G. Elev (ft)5400.76 Element Left OB Channel Right OB
Vel Head (ft)0.39 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5400.37 Reach Len. (ft)1158.00 1239.23 1263.00
Crit W.S. (ft) Flow Area (sq ft)4894.15 4186.94 18.54
E.G. Slope (ft/ft) 0.001716 Area (sq ft)4894.15 4186.94 18.54
Q Total (cfs)34900.00 Flow (cfs)10474.15 24399.92 25.93
Top Width (ft)1989.06 Top Width (ft)1287.26 693.72 8.08
Vel Total (ft/s)3.84 Avg. Vel. (ft/s)2.14 5.83 1.40
Max Chl Dpth (ft)6.46 Hydr. Depth (ft)3.80 6.04 2.29
Conv. Total (cfs) 842407.4 Conv. (cfs)252822.3 588959.2 625.9
Length Wtd. (ft) 1214.79 Wetted Per. (ft)1289.19 694.23 9.24
Min Ch El (ft)5394.00 Shear (lb/sq ft)0.41 0.65 0.21
Alpha 1.71 Stream Power (lb/ft s)0.87 3.77 0.30
Frctn Loss (ft)2.92 Cum Volume (acre-ft) 2077.08 978.85 45.72
C & E Loss (ft)0.03 Cum SA (acres)706.95 261.44 11.69
Floodplain Engineering Report - Appendix A May 2022
A-3
Plan: Existing2 Colorado River Site 1 RS: 26255.61 Profile: PF 1
E.G. Elev (ft)5397.81 Element Left OB Channel Right OB
Vel Head (ft)0.71 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5397.10 Reach Len. (ft)1050.00 1036.15 981.00
Crit W.S. (ft) Flow Area (sq ft)4528.64 3074.86
E.G. Slope (ft/ft) 0.003607 Area (sq ft)4528.64 3074.86
Q Total (cfs)34900.00 Flow (cfs)10531.85 24368.15
Top Width (ft)2397.04 Top Width (ft)1836.69 560.35
Vel Total (ft/s)4.59 Avg. Vel. (ft/s)2.33 7.92
Max Chl Dpth (ft)6.57 Hydr. Depth (ft)2.47 5.49
Conv. Total (cfs) 581124.2 Conv. (cfs)175367.1 405757.1
Length Wtd. (ft) 1035.04 Wetted Per. (ft)1837.99 561.12
Min Ch El (ft)5390.53 Shear (lb/sq ft)0.55 1.23
Alpha 2.16 Stream Power (lb/ft s)1.29 9.78
Frctn Loss (ft)4.11 Cum Volume (acre-ft) 1951.83 875.56 45.46
C & E Loss (ft)0.05 Cum SA (acres)665.43 243.60 11.57
Plan: Existing2 Colorado River Site 1 RS: 25219.46 Profile: PF 1
E.G. Elev (ft)5393.65 Element Left OB Channel Right OB
Vel Head (ft)0.53 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5393.12 Reach Len. (ft)1167.00 1118.45 1053.00
Crit W.S. (ft) Flow Area (sq ft)3974.24 2161.75 1929.18
E.G. Slope (ft/ft) 0.004389 Area (sq ft)3974.24 2161.75 1929.18
Q Total (cfs)34900.00 Flow (cfs)11213.86 16815.01 6871.13
Top Width (ft)2482.74 Top Width (ft)1534.97 469.76 478.00
Vel Total (ft/s)4.33 Avg. Vel. (ft/s)2.82 7.78 3.56
Max Chl Dpth (ft)7.12 Hydr. Depth (ft)2.59 4.60 4.04
Conv. Total (cfs) 526778.8 Conv. (cfs)169261.4 253804.9 103712.5
Length Wtd. (ft) 1129.41 Wetted Per. (ft)1536.54 470.06 478.67
Min Ch El (ft)5388.00 Shear (lb/sq ft)0.71 1.26 1.10
Alpha 1.83 Stream Power (lb/ft s)2.00 9.80 3.93
Frctn Loss (ft)3.42 Cum Volume (acre-ft) 1849.35 813.28 23.73
C & E Loss (ft)0.07 Cum SA (acres)624.79 231.35 6.19
Plan: Existing2 Colorado River Site 1 RS: 24101.01 Profile: PF 1
E.G. Elev (ft)5390.16 Element Left OB Channel Right OB
Vel Head (ft)0.31 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5389.85 Reach Len. (ft)1473.00 1412.79 1111.00
Crit W.S. (ft) Flow Area (sq ft)6932.86 3805.82 3.76
E.G. Slope (ft/ft) 0.002215 Area (sq ft)6932.86 3805.82 3.76
Q Total (cfs)34900.00 Flow (cfs)13813.37 21083.22 3.42
Top Width (ft)3287.24 Top Width (ft)2460.70 822.80 3.74
Vel Total (ft/s)3.25 Avg. Vel. (ft/s)1.99 5.54 0.91
Max Chl Dpth (ft)6.10 Hydr. Depth (ft)2.82 4.63 1.01
Conv. Total (cfs) 741518.9 Conv. (cfs)293492.1 447954.2 72.6
Length Wtd. (ft) 1444.68 Wetted Per. (ft)2461.74 824.44 4.33
Min Ch El (ft)5383.97 Shear (lb/sq ft)0.39 0.64 0.12
Alpha 1.91 Stream Power (lb/ft s)0.78 3.54 0.11
Frctn Loss (ft)4.42 Cum Volume (acre-ft) 1703.25 736.66 0.37
C & E Loss (ft)0.00 Cum SA (acres)571.27 214.75 0.37
Floodplain Engineering Report - Appendix A May 2022
A-4
Plan: Existing2 Colorado River Site 1 RS: 22688.22 Profile: PF 1
E.G. Elev (ft)5385.75 Element Left OB Channel Right OB
Vel Head (ft)0.31 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5385.44 Reach Len. (ft)1763.00 1957.55 2135.00
Crit W.S. (ft) Flow Area (sq ft)9381.75 1689.59 1.40
E.G. Slope (ft/ft) 0.004503 Area (sq ft)9381.75 1689.59 1.40
Q Total (cfs)34900.00 Flow (cfs)23183.79 11714.82 1.40
Top Width (ft)4549.10 Top Width (ft)4103.38 444.13 1.59
Vel Total (ft/s)3.15 Avg. Vel. (ft/s)2.47 6.93 1.00
Max Chl Dpth (ft)5.44 Hydr. Depth (ft)2.29 3.80 0.88
Conv. Total (cfs) 520111.4 Conv. (cfs)345505.8 174584.8 20.9
Length Wtd. (ft) 1819.93 Wetted Per. (ft)4105.57 444.97 2.37
Min Ch El (ft)5380.75 Shear (lb/sq ft)0.64 1.07 0.17
Alpha 2.03 Stream Power (lb/ft s)1.59 7.40 0.17
Frctn Loss (ft)6.43 Cum Volume (acre-ft) 1427.41 647.55 0.30
C & E Loss (ft)0.04 Cum SA (acres)460.29 194.21 0.30
Plan: Existing2 Colorado River Site 1 RS: 20730.67 Profile: PF 1
E.G. Elev (ft)5379.29 Element Left OB Channel Right OB
Vel Head (ft)0.19 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5379.10 Reach Len. (ft)1430.00 1332.44 1200.00
Crit W.S. (ft) Flow Area (sq ft)9692.43 1678.11 1.66
E.G. Slope (ft/ft) 0.002843 Area (sq ft)9692.43 1678.11 1.66
Q Total (cfs)34900.00 Flow (cfs)26195.08 8703.58 1.34
Top Width (ft)3465.37 Top Width (ft)2979.13 483.75 2.48
Vel Total (ft/s)3.07 Avg. Vel. (ft/s)2.70 5.19 0.81
Max Chl Dpth (ft)7.10 Hydr. Depth (ft)3.25 3.47 0.67
Conv. Total (cfs) 654494.4 Conv. (cfs)491247.3 163221.9 25.1
Length Wtd. (ft) 1407.83 Wetted Per. (ft)2981.29 483.92 2.76
Min Ch El (ft)5374.88 Shear (lb/sq ft)0.58 0.62 0.11
Alpha 1.29 Stream Power (lb/ft s)1.56 3.19 0.09
Frctn Loss (ft)3.60 Cum Volume (acre-ft) 1041.41 571.88 0.23
C & E Loss (ft)0.02 Cum SA (acres)316.96 173.36 0.20
Plan: Existing2 Colorado River Site 1 RS: 19398.23 Profile: PF 1
E.G. Elev (ft)5375.67 Element Left OB Channel Right OB
Vel Head (ft)0.12 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5375.54 Reach Len. (ft)1603.00 1689.97 1773.00
Crit W.S. (ft) Flow Area (sq ft)11887.98 1726.70 1.83
E.G. Slope (ft/ft) 0.002315 Area (sq ft)11887.98 1726.70 1.83
Q Total (cfs)34900.00 Flow (cfs)27747.05 7151.50 1.46
Top Width (ft)4038.04 Top Width (ft)3438.84 597.33 1.87
Vel Total (ft/s)2.56 Avg. Vel. (ft/s)2.33 4.14 0.80
Max Chl Dpth (ft)7.57 Hydr. Depth (ft)3.46 2.89 0.98
Conv. Total (cfs) 725334.6 Conv. (cfs)576673.2 148631.1 30.3
Length Wtd. (ft) 1627.88 Wetted Per. (ft)3443.19 598.09 2.66
Min Ch El (ft)5372.00 Shear (lb/sq ft)0.50 0.42 0.10
Alpha 1.19 Stream Power (lb/ft s)1.16 1.73 0.08
Frctn Loss (ft)3.64 Cum Volume (acre-ft) 687.19 519.80 0.18
C & E Loss (ft)0.01 Cum SA (acres)211.62 156.83 0.14
Floodplain Engineering Report - Appendix A May 2022
A-5
Plan: Existing2 Colorado River Site 1 RS: 17708.26 Profile: PF 1
E.G. Elev (ft)5372.02 Element Left OB Channel Right OB
Vel Head (ft)0.21 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5371.81 Reach Len. (ft)2036.00 1873.91 2008.00
Crit W.S. (ft) Flow Area (sq ft)8307.43 2613.22 2.28
E.G. Slope (ft/ft) 0.002164 Area (sq ft)8307.43 2613.22 2.28
Q Total (cfs)34900.00 Flow (cfs)22085.83 12812.57 1.60
Top Width (ft)2547.92 Top Width (ft)1878.96 667.70 1.26
Vel Total (ft/s)3.20 Avg. Vel. (ft/s)2.66 4.90 0.70
Max Chl Dpth (ft)7.78 Hydr. Depth (ft)4.42 3.91 1.81
Conv. Total (cfs) 750235.0 Conv. (cfs)474772.6 275428.0 34.4
Length Wtd. (ft) 1932.91 Wetted Per. (ft)1880.55 668.06 3.82
Min Ch El (ft)5366.00 Shear (lb/sq ft)0.60 0.53 0.08
Alpha 1.30 Stream Power (lb/ft s)1.59 2.59 0.06
Frctn Loss (ft)5.89 Cum Volume (acre-ft) 315.59 435.62 0.10
C & E Loss (ft)0.03 Cum SA (acres)113.77 132.29 0.07
Plan: Existing2 Colorado River Site 1 RS: 15834.35 Profile: PF 1
E.G. Elev (ft)5366.10 Element Left OB Channel Right OB
Vel Head (ft)0.50 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5365.60 Reach Len. (ft)2339.00 1918.66 1085.00
Crit W.S. (ft) Flow Area (sq ft)1642.86 5329.35
E.G. Slope (ft/ft) 0.004607 Area (sq ft)1642.86 5329.35
Q Total (cfs)34900.00 Flow (cfs)3321.21 31578.79
Top Width (ft)2816.48 Top Width (ft)1011.20 1805.29
Vel Total (ft/s)5.01 Avg. Vel. (ft/s)2.02 5.93
Max Chl Dpth (ft)3.69 Hydr. Depth (ft)1.62 2.95
Conv. Total (cfs) 514208.8 Conv. (cfs)48934.0 465274.9
Length Wtd. (ft) 1952.79 Wetted Per. (ft)1011.76 1807.23
Min Ch El (ft)5361.91 Shear (lb/sq ft)0.47 0.85
Alpha 1.28 Stream Power (lb/ft s)0.94 5.03
Frctn Loss (ft)6.10 Cum Volume (acre-ft)83.05 264.78 0.04
C & E Loss (ft)0.05 Cum SA (acres)46.23 79.09 0.05
Plan: Existing2 Colorado River Site 1 RS: 13915.69 Profile: PF 1
E.G. Elev (ft)5359.95 Element Left OB Channel Right OB
Vel Head (ft)0.35 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5359.60 Reach Len. (ft)
Crit W.S. (ft)5358.08 Flow Area (sq ft)1450.64 6693.24 3.56
E.G. Slope (ft/ft) 0.002255 Area (sq ft)1450.64 6693.24 3.56
Q Total (cfs)34900.00 Flow (cfs)2353.24 32543.53 3.23
Top Width (ft)2500.29 Top Width (ft)710.56 1786.08 3.65
Vel Total (ft/s)4.28 Avg. Vel. (ft/s)1.62 4.86 0.91
Max Chl Dpth (ft)5.85 Hydr. Depth (ft)2.04 3.75 0.98
Conv. Total (cfs) 734918.6 Conv. (cfs)49554.1 685296.4 68.1
Length Wtd. (ft) Wetted Per. (ft)710.60 1787.16 4.16
Min Ch El (ft)5353.75 Shear (lb/sq ft)0.29 0.53 0.12
Alpha 1.21 Stream Power (lb/ft s)0.47 2.56 0.11
Frctn Loss (ft) Cum Volume (acre-ft)
C & E Loss (ft) Cum SA (acres)
Floodplain Engineering Report - Appendix A May 2022
A-6
0 500 1000 1500 2000 2500 3000 3500
5404
5406
5408
5410
5412
5414
5416
5418
5420
5422
Colorado River Plan: Existing2 5/14/2020
RS = 30902.14
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 200 400 600 800 1000 1200 1400
5400
5402
5404
5406
5408
5410
5412
5414
5416
Colorado River Plan: Existing2 5/14/2020
RS = 29650.64
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-7
0 200 400 600 800 1000 1200 1400
5400
5405
5410
5415
5420
Colorado River Plan: Existing2 5/14/2020
RS = 29500 BR I-70 Bridge over Colorado River
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .07
0 200 400 600 800 1000 1200 1400
5400
5402
5404
5406
5408
5410
5412
5414
5416
5418
Colorado River Plan: Existing2 5/14/2020
RS = 29500 BR I-70 Bridge over Colorado River
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-8
0 200 400 600 800 1000 1200 1400
5400
5402
5404
5406
5408
5410
5412
5414
Colorado River Plan: Existing2 5/14/2020
RS = 29427.62
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .07
0 500 1000 1500 2000 2500
5390
5400
5410
5420
5430
5440
5450
Colorado River Plan: Existing2 5/14/2020
RS = 27494.84
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-9
0 500 1000 1500 2000 2500 3000 3500
5390
5400
5410
5420
5430
5440
Colorado River Plan: Existing2 5/14/2020
RS = 26255.61
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 1000 2000 3000 4000
5380
5390
5400
5410
5420
5430
Colorado River Plan: Existing2 5/14/2020
RS = 25219.46
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-10
0 1000 2000 3000 4000 5000
5380
5390
5400
5410
5420
5430
Colorado River Plan: Existing2 5/14/2020
RS = 24101.01
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 1000 2000 3000 4000 5000 6000
5380
5390
5400
5410
5420
5430
Colorado River Plan: Existing2 5/14/2020
RS = 22688.22
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-11
0 1000 2000 3000 4000 5000 6000
5370
5380
5390
5400
5410
5420
5430
5440
Colorado River Plan: Existing2 5/14/2020
RS = 20730.67
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 1000 2000 3000 4000 5000 6000 7000
5360
5370
5380
5390
5400
5410
5420
5430
Colorado River Plan: Existing2 5/14/2020
RS = 19398.23
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-12
0 1000 2000 3000 4000 5000 6000 7000
5350
5360
5370
5380
5390
5400
5410
5420
5430
Colorado River Plan: Existing2 5/14/2020
RS = 17708.26
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 1000 2000 3000 4000 5000
5360
5365
5370
5375
5380
5385
Colorado River Plan: Existing2 5/14/2020
RS = 15834.35
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .
0
7
Floodplain Engineering Report - Appendix A May 2022
A-13
0 1000 2000 3000 4000
5350
5355
5360
5365
5370
5375
5380
5385
5390
Colorado River Plan: Existing2 5/14/2020
RS = 13915.69
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .
0
7
Floodplain Engineering Report - Appendix A May 2022
A-14
HEC-RAS Plan: Proposed2 River: Colorado River Reach: Site 1 Profile: PF 1
Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl
(cfs) (ft) (ft) (ft) (ft)(ft/ft) (ft/s) (sq ft) (ft)
Site 1 30902.14 PF 1 34900.0 5404.0 5412.3 5412.5 0.0 5.00 14244.1 2641.0 0.31
Site 1 29650.64 PF 1 34900.0 5400.0 5409.4 5406.4 5410.7 0.0 9.17 3806.1 431.7 0.54
Site 1 29500 Bridge
Site 1 29427.62 PF 1 34900.0 5400.0 5406.2 5406.2 5409.1 0.0 13.75 2538.0 435.3 1.00
Site 1 27494.84 PF 1 34900.0 5394.0 5400.4 5400.8 0.0 5.85 9057.0 1988.9 0.42
Site 1 26255.61 PF 1 34900.0 5390.5 5397.1 5397.8 0.0 7.93 7604.5 2396.3 0.60
Site 1 25219.46 PF 1 34900.0 5388.0 5393.1 5393.6 0.0 7.80 8060.1 2481.8 0.64
Site 1 24101.01 PF 1 34900.0 5384.0 5389.9 5390.2 0.0 5.53 10767.1 3290.2 0.45
Site 1 22688.22 PF 1 34900.0 5380.8 5385.4 5385.8 0.0 6.95 10118.4 3654.6 0.63
Site 1 20730.67 PF 1 34900.0 5374.9 5379.1 5379.3 0.0 5.18 11396.7 3505.0 0.49
Site 1 19398.23 PF 1 34900.0 5372.0 5375.5 5375.6 0.0 4.12 13583.7 4022.9 0.43
Site 1 17708.26 PF 1 34900.0 5366.0 5371.8 5372.0 0.0 4.87 10968.8 2550.1 0.43
Site 1 15834.35 PF 1 34900.0 5361.9 5365.6 5366.1 0.0 5.93 6965.2 2814.3 0.61
Site 1 13915.69 PF 1 34900.0 5353.7 5359.6 5358.1 5359.9 0.0 4.86 8149.5 2491.9 0.44
Floodplain Engineering Report - Appendix A May 2022
A-15
Plan: Proposed2 Colorado River Site 1 RS: 30902.14 Profile: PF 1
E.G. Elev (ft)5412.53 Element Left OB Channel Right OB
Vel Head (ft)0.19 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5412.34 Reach Len. (ft)1356.00 1251.50 946.00
Crit W.S. (ft) Flow Area (sq ft)7426.19 2950.85 3867.08
E.G. Slope (ft/ft) 0.000840 Area (sq ft)7426.19 2950.85 3867.08
Q Total (cfs)34900.00 Flow (cfs)13121.90 14743.20 7034.90
Top Width (ft)2641.05 Top Width (ft)1523.66 360.17 757.21
Vel Total (ft/s)2.45 Avg. Vel. (ft/s)1.77 5.00 1.82
Max Chl Dpth (ft)8.34 Hydr. Depth (ft)4.87 8.19 5.11
Conv. Total (cfs) 1204513.0 Conv. (cfs)452879.5 508836.0 242797.4
Length Wtd. (ft)1240.36 Wetted Per. (ft)1525.06 360.49 760.22
Min Ch El (ft)5404.00 Shear (lb/sq ft)0.26 0.43 0.27
Alpha 2.06 Stream Power (lb/ft s)0.45 2.14 0.49
Frctn Loss (ft)1.69 Cum Volume (acre-ft) 2226.64 1240.44 87.86
C & E Loss (ft)0.11 Cum SA (acres)715.85 300.03 20.12
Plan: Proposed2 Colorado River Site 1 RS: 29650.64 Profile: PF 1
E.G. Elev (ft)5410.73 Element Left OB Channel Right OB
Vel Head (ft)1.31 Wt. n-Val. 0.035
W.S. Elev (ft)5409.43 Reach Len. (ft)10.00 10.00 10.00
Crit W.S. (ft)5406.35 Flow Area (sq ft) 3806.14
E.G. Slope (ft/ft) 0.002587 Area (sq ft) 3806.14
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)431.69 Top Width (ft) 431.69
Vel Total (ft/s)9.17 Avg. Vel. (ft/s) 9.17
Max Chl Dpth (ft)9.42 Hydr. Depth (ft) 8.82
Conv. Total (cfs) 686135.0 Conv. (cfs) 686135.0
Length Wtd. (ft)10.00 Wetted Per. (ft) 435.00
Min Ch El (ft)5400.00 Shear (lb/sq ft) 1.41
Alpha 1.00 Stream Power (lb/ft s) 12.96
Frctn Loss (ft)0.03 Cum Volume (acre-ft) 2111.05 1143.37 45.87
C & E Loss (ft)0.05 Cum SA (acres)692.14 288.66 11.90
Plan: Proposed2 Colorado River Site 1 RS: 29500 BR U Profile: PF 1
E.G. Elev (ft)5410.65 Element Left OB Channel Right OB
Vel Head (ft)1.47 Wt. n-Val. 0.035
W.S. Elev (ft)5409.19 Reach Len. (ft)195.00 195.00 195.00
Crit W.S. (ft)5406.53 Flow Area (sq ft) 3593.16
E.G. Slope (ft/ft) 0.003544 Area (sq ft) 3593.16
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)418.62 Top Width (ft) 418.62
Vel Total (ft/s)9.71 Avg. Vel. (ft/s) 9.71
Max Chl Dpth (ft)9.19 Hydr. Depth (ft) 8.58
Conv. Total (cfs) 586246.7 Conv. (cfs) 586246.7
Length Wtd. (ft)195.00 Wetted Per. (ft) 476.94
Min Ch El (ft)5400.00 Shear (lb/sq ft) 1.67
Alpha 1.00 Stream Power (lb/ft s) 16.19
Frctn Loss (ft)0.93 Cum Volume (acre-ft) 2111.05 1142.52 45.87
C & E Loss (ft)0.21 Cum SA (acres)692.14 288.56 11.90
Floodplain Engineering Report - Appendix A May 2022
A-16
Plan: Proposed2 Colorado River Site 1 RS: 29500 BR D Profile: PF 1
E.G. Elev (ft)5409.51 Element Left OB Channel Right OB
Vel Head (ft)2.16 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5407.36 Reach Len. (ft)18.02 18.02 18.02
Crit W.S. (ft)5406.34 Flow Area (sq ft)2.10 2961.65
E.G. Slope (ft/ft) 0.006797 Area (sq ft)2.10 2961.65
Q Total (cfs)34900.00 Flow (cfs)0.72 34899.28
Top Width (ft)460.53 Top Width (ft)27.15 433.38
Vel Total (ft/s)11.78 Avg. Vel. (ft/s)0.34 11.78
Max Chl Dpth (ft)7.35 Hydr. Depth (ft)0.08 6.83
Conv. Total (cfs) 423303.0 Conv. (cfs)8.8 423294.2
Length Wtd. (ft)18.02 Wetted Per. (ft)27.34 479.47
Min Ch El (ft)5400.00 Shear (lb/sq ft)0.03 2.62
Alpha 1.00 Stream Power (lb/ft s)0.01 30.89
Frctn Loss (ft)0.15 Cum Volume (acre-ft) 2111.05 1127.85 45.87
C & E Loss (ft)0.23 Cum SA (acres)692.08 286.65 11.90
Plan: Proposed2 Colorado River Site 1 RS: 29427.62 Profile: PF 1
E.G. Elev (ft)5409.13 Element Left OB Channel Right OB
Vel Head (ft)2.94 Wt. n-Val. 0.035
W.S. Elev (ft)5406.19 Reach Len. (ft)1192.00 1932.78 2126.00
Crit W.S. (ft)5406.19 Flow Area (sq ft) 2538.02
E.G. Slope (ft/ft) 0.010048 Area (sq ft) 2538.02
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)435.29 Top Width (ft) 435.29
Vel Total (ft/s)13.75 Avg. Vel. (ft/s) 13.75
Max Chl Dpth (ft)6.19 Hydr. Depth (ft) 5.83
Conv. Total (cfs) 348159.0 Conv. (cfs) 348159.0
Length Wtd. (ft) 1822.27 Wetted Per. (ft) 436.98
Min Ch El (ft)5400.00 Shear (lb/sq ft) 3.64
Alpha 1.00 Stream Power (lb/ft s) 50.10
Frctn Loss (ft)6.32 Cum Volume (acre-ft) 2111.05 1126.71 45.87
C & E Loss (ft)1.27 Cum SA (acres)692.07 286.47 11.90
Plan: Proposed2 Colorado River Site 1 RS: 27494.84 Profile: PF 1
E.G. Elev (ft)5400.76 Element Left OB Channel Right OB
Vel Head (ft)0.39 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5400.36 Reach Len. (ft)1158.00 1239.23 1263.00
Crit W.S. (ft) Flow Area (sq ft)4861.16 4177.35 18.47
E.G. Slope (ft/ft) 0.001737 Area (sq ft)4861.16 4177.35 18.47
Q Total (cfs)34900.00 Flow (cfs)10420.06 24453.99 25.95
Top Width (ft)1988.92 Top Width (ft)1287.13 693.72 8.07
Vel Total (ft/s)3.85 Avg. Vel. (ft/s)2.14 5.85 1.41
Max Chl Dpth (ft)6.45 Hydr. Depth (ft)3.78 6.02 2.29
Conv. Total (cfs) 837333.6 Conv. (cfs)250001.9 586709.1 622.6
Length Wtd. (ft) 1214.72 Wetted Per. (ft)1289.08 694.24 9.23
Min Ch El (ft)5394.00 Shear (lb/sq ft)0.41 0.65 0.22
Alpha 1.71 Stream Power (lb/ft s)0.88 3.82 0.30
Frctn Loss (ft)2.95 Cum Volume (acre-ft) 2044.53 977.73 45.42
C & E Loss (ft)0.03 Cum SA (acres)674.46 261.42 11.70
Floodplain Engineering Report - Appendix A May 2022
A-17
Plan: Proposed2 Colorado River Site 1 RS: 26255.61 Profile: PF 1
E.G. Elev (ft)5397.78 Element Left OB Channel Right OB
Vel Head (ft)0.71 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5397.07 Reach Len. (ft)1050.00 1036.15 981.00
Crit W.S. (ft) Flow Area (sq ft)4547.55 3056.94
E.G. Slope (ft/ft) 0.003637 Area (sq ft)4547.55 3056.94
Q Total (cfs)34900.00 Flow (cfs)10650.84 24249.15
Top Width (ft)2396.30 Top Width (ft)1836.46 559.84
Vel Total (ft/s)4.59 Avg. Vel. (ft/s)2.34 7.93
Max Chl Dpth (ft)6.54 Hydr. Depth (ft)2.48 5.46
Conv. Total (cfs) 578683.9 Conv. (cfs)176603.8 402080.1
Length Wtd. (ft) 1035.12 Wetted Per. (ft)1837.77 560.58
Min Ch El (ft)5390.53 Shear (lb/sq ft)0.56 1.24
Alpha 2.16 Stream Power (lb/ft s)1.32 9.82
Frctn Loss (ft)4.10 Cum Volume (acre-ft) 1919.47 874.83 45.16
C & E Loss (ft)0.05 Cum SA (acres)632.94 243.59 11.58
Plan: Proposed2 Colorado River Site 1 RS: 25219.46 Profile: PF 1
E.G. Elev (ft)5393.63 Element Left OB Channel Right OB
Vel Head (ft)0.54 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5393.09 Reach Len. (ft)1167.00 1118.45 1053.00
Crit W.S. (ft) Flow Area (sq ft)3947.71 2196.65 1915.77
E.G. Slope (ft/ft) 0.004325 Area (sq ft)3947.71 2196.65 1915.77
Q Total (cfs)34900.00 Flow (cfs)11015.23 17142.44 6742.32
Top Width (ft)2481.76 Top Width (ft)1534.07 469.76 477.93
Vel Total (ft/s)4.33 Avg. Vel. (ft/s)2.79 7.80 3.52
Max Chl Dpth (ft)7.09 Hydr. Depth (ft)2.57 4.68 4.01
Conv. Total (cfs) 530694.1 Conv. (cfs)167499.1 260670.3 102524.6
Length Wtd. (ft) 1129.40 Wetted Per. (ft)1535.65 470.06 478.59
Min Ch El (ft)5388.00 Shear (lb/sq ft)0.69 1.26 1.08
Alpha 1.85 Stream Power (lb/ft s)1.94 9.85 3.80
Frctn Loss (ft)3.39 Cum Volume (acre-ft) 1817.09 812.35 23.58
C & E Loss (ft)0.07 Cum SA (acres)592.32 231.35 6.20
Plan: Proposed2 Colorado River Site 1 RS: 24101.01 Profile: PF 1
E.G. Elev (ft)5390.18 Element Left OB Channel Right OB
Vel Head (ft)0.31 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5389.86 Reach Len. (ft)1473.00 1412.79 1111.00
Crit W.S. (ft) Flow Area (sq ft)6950.58 3812.73 3.74
E.G. Slope (ft/ft) 0.002201 Area (sq ft)6950.58 3812.73 3.74
Q Total (cfs)34900.00 Flow (cfs)13817.05 21079.60 3.36
Top Width (ft)3290.17 Top Width (ft)2463.58 822.80 3.79
Vel Total (ft/s)3.24 Avg. Vel. (ft/s)1.99 5.53 0.90
Max Chl Dpth (ft)6.11 Hydr. Depth (ft)2.82 4.63 0.99
Conv. Total (cfs) 743889.4 Conv. (cfs)294508.8 449309.1 71.5
Length Wtd. (ft) 1444.67 Wetted Per. (ft)2464.64 824.45 4.37
Min Ch El (ft)5383.97 Shear (lb/sq ft)0.39 0.64 0.12
Alpha 1.91 Stream Power (lb/ft s)0.77 3.51 0.11
Frctn Loss (ft)4.42 Cum Volume (acre-ft) 1671.10 735.20 0.38
C & E Loss (ft)0.00 Cum SA (acres)538.77 214.75 0.38
Floodplain Engineering Report - Appendix A May 2022
A-18
Plan: Proposed2 Colorado River Site 1 RS: 22688.22 Profile: PF 1
E.G. Elev (ft)5385.76 Element Left OB Channel Right OB
Vel Head (ft)0.33 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5385.43 Reach Len. (ft)1763.00 1957.55 2135.00
Crit W.S. (ft) Flow Area (sq ft)8428.58 1688.44 1.39
E.G. Slope (ft/ft) 0.004527 Area (sq ft)8428.58 1688.44 1.39
Q Total (cfs)34900.00 Flow (cfs)23165.64 11732.96 1.40
Top Width (ft)3654.56 Top Width (ft)3208.84 444.13 1.59
Vel Total (ft/s)3.45 Avg. Vel. (ft/s)2.75 6.95 1.00
Max Chl Dpth (ft)5.43 Hydr. Depth (ft)2.63 3.80 0.88
Conv. Total (cfs) 518707.7 Conv. (cfs)344303.6 174383.3 20.8
Length Wtd. (ft) 1819.93 Wetted Per. (ft)3211.26 444.98 2.37
Min Ch El (ft)5380.75 Shear (lb/sq ft)0.74 1.07 0.17
Alpha 1.79 Stream Power (lb/ft s)2.04 7.45 0.17
Frctn Loss (ft)6.45 Cum Volume (acre-ft) 1411.07 645.99 0.32
C & E Loss (ft)0.04 Cum SA (acres)442.86 194.21 0.31
Plan: Proposed2 Colorado River Site 1 RS: 20730.67 Profile: PF 1
E.G. Elev (ft)5379.28 Element Left OB Channel Right OB
Vel Head (ft)0.19 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5379.09 Reach Len. (ft)1430.00 1332.44 1200.00
Crit W.S. (ft) Flow Area (sq ft)9719.50 1675.51 1.65
E.G. Slope (ft/ft) 0.002846 Area (sq ft)9719.50 1675.51 1.65
Q Total (cfs)34900.00 Flow (cfs)26213.27 8685.40 1.33
Top Width (ft)3504.97 Top Width (ft)3018.75 483.75 2.47
Vel Total (ft/s)3.06 Avg. Vel. (ft/s)2.70 5.18 0.80
Max Chl Dpth (ft)7.09 Hydr. Depth (ft)3.22 3.46 0.67
Conv. Total (cfs) 654172.5 Conv. (cfs)491346.7 162800.9 24.9
Length Wtd. (ft) 1408.01 Wetted Per. (ft)3020.93 483.92 2.75
Min Ch El (ft)5374.88 Shear (lb/sq ft)0.57 0.62 0.11
Alpha 1.30 Stream Power (lb/ft s)1.54 3.19 0.09
Frctn Loss (ft)3.62 Cum Volume (acre-ft) 1043.82 570.40 0.24
C & E Loss (ft)0.02 Cum SA (acres)316.84 173.36 0.21
Plan: Proposed2 Colorado River Site 1 RS: 19398.23 Profile: PF 1
E.G. Elev (ft)5375.64 Element Left OB Channel Right OB
Vel Head (ft)0.12 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5375.52 Reach Len. (ft)1603.00 1689.97 1773.00
Crit W.S. (ft) Flow Area (sq ft)11874.22 1707.57 1.89
E.G. Slope (ft/ft) 0.002331 Area (sq ft)11874.22 1707.57 1.89
Q Total (cfs)34900.00 Flow (cfs)27854.81 7043.63 1.56
Top Width (ft)4022.93 Top Width (ft)3423.81 597.33 1.80
Vel Total (ft/s)2.57 Avg. Vel. (ft/s)2.35 4.12 0.83
Max Chl Dpth (ft)7.52 Hydr. Depth (ft)3.47 2.86 1.05
Conv. Total (cfs) 722901.5 Conv. (cfs)576970.9 145898.2 32.4
Length Wtd. (ft) 1627.56 Wetted Per. (ft)3428.90 598.09 2.61
Min Ch El (ft)5372.00 Shear (lb/sq ft)0.50 0.42 0.11
Alpha 1.19 Stream Power (lb/ft s)1.18 1.71 0.09
Frctn Loss (ft)3.64 Cum Volume (acre-ft) 689.38 518.66 0.19
C & E Loss (ft)0.01 Cum SA (acres)211.09 156.82 0.15
Floodplain Engineering Report - Appendix A May 2022
A-19
Plan: Proposed2 Colorado River Site 1 RS: 17708.26 Profile: PF 1
E.G. Elev (ft)5372.00 Element Left OB Channel Right OB
Vel Head (ft)0.20 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5371.79 Reach Len. (ft)2036.00 1873.91 2008.00
Crit W.S. (ft) Flow Area (sq ft)8365.50 2600.77 2.55
E.G. Slope (ft/ft) 0.002147 Area (sq ft)8365.50 2600.77 2.55
Q Total (cfs)34900.00 Flow (cfs)22240.87 12657.13 2.01
Top Width (ft)2550.15 Top Width (ft)1880.85 667.70 1.60
Vel Total (ft/s)3.18 Avg. Vel. (ft/s)2.66 4.87 0.79
Max Chl Dpth (ft)7.76 Hydr. Depth (ft)4.45 3.90 1.60
Conv. Total (cfs) 753201.6 Conv. (cfs)479995.9 273162.4 43.4
Length Wtd. (ft) 1933.27 Wetted Per. (ft)1882.43 668.37 3.57
Min Ch El (ft)5366.00 Shear (lb/sq ft)0.60 0.52 0.10
Alpha 1.29 Stream Power (lb/ft s)1.58 2.54 0.08
Frctn Loss (ft)5.87 Cum Volume (acre-ft) 316.97 435.08 0.10
C & E Loss (ft)0.03 Cum SA (acres)113.48 132.29 0.08
Plan: Proposed2 Colorado River Site 1 RS: 15834.35 Profile: PF 1
E.G. Elev (ft)5366.09 Element Left OB Channel Right OB
Vel Head (ft)0.50 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5365.59 Reach Len. (ft)2339.00 1918.66 1085.00
Crit W.S. (ft) Flow Area (sq ft)1639.42 5325.82
E.G. Slope (ft/ft) 0.004618 Area (sq ft)1639.42 5325.82
Q Total (cfs)34900.00 Flow (cfs)3317.93 31582.07
Top Width (ft)2814.33 Top Width (ft)1009.07 1805.27
Vel Total (ft/s)5.01 Avg. Vel. (ft/s)2.02 5.93
Max Chl Dpth (ft)3.68 Hydr. Depth (ft)1.62 2.95
Conv. Total (cfs) 513590.6 Conv. (cfs)48826.9 464763.8
Length Wtd. (ft) 1953.00 Wetted Per. (ft)1009.63 1807.21
Min Ch El (ft)5361.91 Shear (lb/sq ft)0.47 0.85
Alpha 1.28 Stream Power (lb/ft s)0.95 5.04
Frctn Loss (ft)6.10 Cum Volume (acre-ft)83.15 264.59 0.04
C & E Loss (ft)0.05 Cum SA (acres)45.94 79.09 0.05
Plan: Proposed2 Colorado River Site 1 RS: 13915.69 Profile: PF 1
E.G. Elev (ft)5359.94 Element Left OB Channel Right OB
Vel Head (ft)0.34 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5359.60 Reach Len. (ft)
Crit W.S. (ft)5358.10 Flow Area (sq ft)1457.74 6688.19 3.55
E.G. Slope (ft/ft) 0.002255 Area (sq ft)1457.74 6688.19 3.55
Q Total (cfs)34900.00 Flow (cfs)2391.44 32505.35 3.22
Top Width (ft)2491.92 Top Width (ft)702.19 1786.08 3.64
Vel Total (ft/s)4.28 Avg. Vel. (ft/s)1.64 4.86 0.91
Max Chl Dpth (ft)5.91 Hydr. Depth (ft)2.08 3.74 0.97
Conv. Total (cfs) 734863.5 Conv. (cfs)50354.7 684441.1 67.7
Length Wtd. (ft) Wetted Per. (ft)702.24 1787.14 4.16
Min Ch El (ft)5353.69 Shear (lb/sq ft)0.29 0.53 0.12
Alpha 1.21 Stream Power (lb/ft s)0.48 2.56 0.11
Frctn Loss (ft) Cum Volume (acre-ft)
C & E Loss (ft) Cum SA (acres)
Floodplain Engineering Report - Appendix A May 2022
A-20
0 500 1000 1500 2000 2500 3000 3500
5404
5406
5408
5410
5412
5414
5416
5418
5420
5422
Colorado River Plan: Proposed2 5/14/2020
RS = 30902.14
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 200 400 600 800 1000 1200 1400
5400
5402
5404
5406
5408
5410
5412
5414
5416
Colorado River Plan: Proposed2 5/14/2020
RS = 29650.64
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-21
0 200 400 600 800 1000 1200 1400
5400
5405
5410
5415
5420
Colorado River Plan: Proposed2 5/14/2020
RS = 29500 BR I-70 Bridge over Colorado River
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .07
0 200 400 600 800 1000 1200 1400
5400
5402
5404
5406
5408
5410
5412
5414
5416
5418
Colorado River Plan: Proposed2 5/14/2020
RS = 29500 BR I-70 Bridge over Colorado River
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-22
0 200 400 600 800 1000 1200 1400
5400
5402
5404
5406
5408
5410
5412
5414
Colorado River Plan: Proposed2 5/14/2020
RS = 29427.62
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .07
0 500 1000 1500 2000 2500
5390
5400
5410
5420
5430
5440
5450
Colorado River Plan: Proposed2 5/14/2020
RS = 27494.84
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-23
0 500 1000 1500 2000 2500 3000 3500
5390
5400
5410
5420
5430
5440
Colorado River Plan: Proposed2 5/14/2020
RS = 26255.61
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 1000 2000 3000 4000
5380
5390
5400
5410
5420
5430
Colorado River Plan: Proposed2 5/14/2020
RS = 25219.46
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-24
0 1000 2000 3000 4000 5000
5380
5390
5400
5410
5420
5430
Colorado River Plan: Proposed2 5/14/2020
RS = 24101.01
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 1000 2000 3000 4000 5000 6000
5350
5360
5370
5380
5390
5400
5410
5420
5430
Colorado River Plan: Proposed2 5/14/2020
RS = 22688.22
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-25
0 1000 2000 3000 4000 5000 6000
5340
5360
5380
5400
5420
5440
Colorado River Plan: Proposed2 5/14/2020
RS = 20730.67
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 1000 2000 3000 4000 5000 6000 7000
5360
5370
5380
5390
5400
5410
5420
5430
Colorado River Plan: Proposed2 5/14/2020
RS = 19398.23
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
Floodplain Engineering Report - Appendix A May 2022
A-26
0 1000 2000 3000 4000 5000 6000 7000
5350
5360
5370
5380
5390
5400
5410
5420
5430
Colorado River Plan: Proposed2 5/14/2020
RS = 17708.26
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .07
0 1000 2000 3000 4000 5000
5360
5365
5370
5375
5380
5385
Colorado River Plan: Proposed2 5/14/2020
RS = 15834.35
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Ground
Bank Sta
.07 .035 .
0
7
Floodplain Engineering Report - Appendix A May 2022
A-27
0 1000 2000 3000 4000
5350
5355
5360
5365
5370
5375
5380
5385
5390
Colorado River Plan: Proposed2 5/14/2020
RS = 13915.69
Station (ft)Elevation (ft)Legend
EG PF 1
WS PF 1
Crit PF 1
Ground
Bank Sta
.07 .035 .
0
7
Floodplain Engineering Report - Appendix A May 2022
A-28
HEC-RAS Plan: FwayM1 River: Colorado River Reach: Site 1
Reach River Sta Profile W.S. Elev Prof Delta WS E.G. Elev Top Wdth Act Q Left Q Channel Q Right Enc Sta L Ch Sta L Ch Sta R Enc Sta R
(ft) (ft) (ft) (ft)(cfs) (cfs) (cfs) (ft)(ft)(ft)(ft)
Site 1 30902.14 PF 1 5412.34 5412.53 2641.05 13121.90 14743.20 7034.90 1956.95 2317.12
Site 1 30902.14 PF 2 5412.85 0.50 5413.58 824.33 8160.65 24671.19 2068.16 1597.59 1956.95 2317.12 2421.92
Site 1 29650.64 PF 1 5409.43 5410.73 431.69 34900.00 336.82 798.40
Site 1 29650.64 PF 2 5409.42 0.00 5410.73 431.69 34900.00 326.82 336.82 798.40 808.41
Site 1 29500 BR U PF 1 5409.19 5410.65 418.62 34900.00 336.82 798.40
Site 1 29500 BR U PF 2 5409.19 0.00 5410.65 418.62 34900.00 326.82 336.82 798.40 808.41
Site 1 29500 BR D PF 1 5407.36 5409.51 461.09 0.75 34899.26 366.90 982.50
Site 1 29500 BR D PF 2 5407.36 0.00 5409.51 433.40 34900.00 356.90 366.90 982.50 992.50
Site 1 29427.62 PF 1 5406.19 5409.13 435.29 34900.00 366.90 982.50
Site 1 29427.62 PF 2 5406.19 0.00 5409.13 435.29 34900.00 356.90 366.90 982.50 992.50
Site 1 27494.84 PF 1 5400.36 5400.76 1988.92 10420.06 24453.99 25.95 1401.12 2094.84
Site 1 27494.84 PF 2 5400.86 0.50 5401.32 1371.76 7679.25 27187.41 33.34 731.93 1401.12 2094.84 2104.84
Site 1 26255.61 PF 1 5397.07 5397.78 2396.30 10650.84 24249.15 1974.18 2547.44
Site 1 26255.61 PF 2 5397.57 0.50 5398.42 1590.65 7356.71 27543.29 950.92 1974.18 2547.44 2557.44
Site 1 25219.46 PF 1 5393.09 5393.63 2481.76 11015.23 17142.44 6742.32 2483.80 2953.56
Site 1 25219.46 PF 2 5393.37 0.28 5394.10 1761.84 12335.27 19989.61 2575.12 1391.78 2483.80 2953.56 3153.62
Site 1 24101.01 PF 1 5389.86 5390.18 3290.17 13817.05 21079.60 3.36 3158.24 3981.04
Site 1 24101.01 PF 2 5390.36 0.50 5390.71 2391.96 11523.21 23375.09 1.70 1590.08 3158.24 3981.04 3982.04
Site 1 22688.22 PF 1 5385.43 5385.76 3654.56 23165.64 11732.96 1.40 4559.40 5003.53
Site 1 22688.22 PF 2 5385.94 0.50 5386.45 2603.56 19643.42 15253.69 2.90 2402.02 4559.40 5003.53 5018.53
Site 1 20730.67 PF 1 5379.09 5379.28 3504.97 26213.27 8685.40 1.33 4964.81 5448.56
Site 1 20730.67 PF 2 5379.59 0.50 5379.85 2135.99 24443.68 10453.36 2.96 3270.79 4964.81 5448.56 5510.56
Site 1 19398.23 PF 1 5375.52 5375.64 4022.92 27855.12 7043.32 1.56 5386.70 5984.03
Site 1 19398.23 PF 2 5376.02 0.50 5376.19 2931.68 26189.41 8710.59 3012.35 5386.70 5984.03 5944.03
Site 1 17708.26 PF 1 5371.79 5372.00 2550.16 22240.22 12657.77 2.01 5073.60 5741.30
Site 1 17708.26 PF 2 5372.30 0.50 5372.53 2153.90 19964.22 14932.92 2.86 3589.25 5073.60 5741.30 5751.30
Site 1 15834.35 PF 1 5365.59 5366.09 2814.29 3317.35 31582.65 3062.93 4872.42
Site 1 15834.35 PF 2 5365.49 -0.10 5366.21 1810.39 1.50 34898.50 3052.93 3062.93 4872.42 4882.42
Site 1 13915.69 PF 1 5359.60 5359.94 2492.14 2392.54 32504.24 3.22 1945.13 3731.21
Site 1 13915.69 PF 2 5360.10 0.50 5360.43 1800.91 26.48 34868.43 5.09 1935.13 1945.13 3731.21 3741.21
Floodplain Engineering Report - Appendix A May 2022
A-29
Plan: FwayM1 Colorado River Site 1 RS: 30902.14 Profile: PF 1
E.G. Elev (ft)5412.53 Element Left OB Channel Right OB
Vel Head (ft)0.19 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5412.34 Reach Len. (ft)1356.00 1251.50 946.00
Crit W.S. (ft) Flow Area (sq ft)7426.19 2950.85 3867.08
E.G. Slope (ft/ft) 0.000840 Area (sq ft)7426.19 2950.85 3867.08
Q Total (cfs)34900.00 Flow (cfs)13121.90 14743.20 7034.90
Top Width (ft)2641.05 Top Width (ft)1523.66 360.17 757.21
Vel Total (ft/s)2.45 Avg. Vel. (ft/s)1.77 5.00 1.82
Max Chl Dpth (ft)8.34 Hydr. Depth (ft)4.87 8.19 5.11
Conv. Total (cfs) 1204513.0 Conv. (cfs)452879.5 508836.0 242797.4
Length Wtd. (ft)1240.36 Wetted Per. (ft)1525.06 360.49 760.22
Min Ch El (ft)5404.00 Shear (lb/sq ft)0.26 0.43 0.27
Alpha 2.06 Stream Power (lb/ft s)0.45 2.14 0.49
Frctn Loss (ft)1.69 Cum Volume (acre-ft) 2226.71 1240.51 87.86
C & E Loss (ft)0.11 Cum SA (acres)715.86 300.03 20.12
Plan: FwayM1 Colorado River Site 1 RS: 29650.64 Profile: PF 1
E.G. Elev (ft)5410.73 Element Left OB Channel Right OB
Vel Head (ft)1.31 Wt. n-Val. 0.035
W.S. Elev (ft)5409.43 Reach Len. (ft)10.00 10.00 10.00
Crit W.S. (ft)5406.35 Flow Area (sq ft) 3806.14
E.G. Slope (ft/ft) 0.002587 Area (sq ft) 3806.14
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)431.69 Top Width (ft) 431.69
Vel Total (ft/s)9.17 Avg. Vel. (ft/s) 9.17
Max Chl Dpth (ft)9.42 Hydr. Depth (ft) 8.82
Conv. Total (cfs) 686135.0 Conv. (cfs) 686135.0
Length Wtd. (ft)10.00 Wetted Per. (ft) 435.00
Min Ch El (ft)5400.00 Shear (lb/sq ft) 1.41
Alpha 1.00 Stream Power (lb/ft s) 12.96
Frctn Loss (ft)0.03 Cum Volume (acre-ft) 2111.12 1143.44 45.87
C & E Loss (ft)0.05 Cum SA (acres)692.14 288.66 11.90
Plan: FwayM1 Colorado River Site 1 RS: 29500 BR U Profile: PF 1
E.G. Elev (ft)5410.65 Element Left OB Channel Right OB
Vel Head (ft)1.47 Wt. n-Val. 0.035
W.S. Elev (ft)5409.19 Reach Len. (ft)195.00 195.00 195.00
Crit W.S. (ft)5406.53 Flow Area (sq ft) 3593.37
E.G. Slope (ft/ft) 0.003543 Area (sq ft) 3593.37
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)418.62 Top Width (ft) 418.62
Vel Total (ft/s)9.71 Avg. Vel. (ft/s) 9.71
Max Chl Dpth (ft)9.19 Hydr. Depth (ft) 8.58
Conv. Total (cfs) 586297.9 Conv. (cfs) 586297.9
Length Wtd. (ft)195.00 Wetted Per. (ft) 476.94
Min Ch El (ft)5400.00 Shear (lb/sq ft) 1.67
Alpha 1.00 Stream Power (lb/ft s) 16.19
Frctn Loss (ft)0.93 Cum Volume (acre-ft) 2111.12 1142.59 45.87
C & E Loss (ft)0.21 Cum SA (acres)692.14 288.56 11.90
Floodplain Engineering Report - Appendix A May 2022
A-30
Plan: FwayM1 Colorado River Site 1 RS: 29500 BR D Profile: PF 1
E.G. Elev (ft)5409.51 Element Left OB Channel Right OB
Vel Head (ft)2.16 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5407.36 Reach Len. (ft)18.02 18.02 18.02
Crit W.S. (ft)5406.35 Flow Area (sq ft)2.15 2962.49
E.G. Slope (ft/ft) 0.006792 Area (sq ft)2.15 2962.49
Q Total (cfs)34900.00 Flow (cfs)0.75 34899.26
Top Width (ft)461.09 Top Width (ft)27.69 433.40
Vel Total (ft/s)11.77 Avg. Vel. (ft/s)0.35 11.78
Max Chl Dpth (ft)7.36 Hydr. Depth (ft)0.08 6.84
Conv. Total (cfs) 423488.1 Conv. (cfs)9.0 423479.0
Length Wtd. (ft)18.02 Wetted Per. (ft)27.87 479.50
Min Ch El (ft)5400.00 Shear (lb/sq ft)0.03 2.62
Alpha 1.00 Stream Power (lb/ft s)0.01 30.86
Frctn Loss (ft)0.15 Cum Volume (acre-ft) 2111.12 1127.92 45.87
C & E Loss (ft)0.23 Cum SA (acres)692.08 286.65 11.90
Plan: FwayM1 Colorado River Site 1 RS: 29427.62 Profile: PF 1
E.G. Elev (ft)5409.13 Element Left OB Channel Right OB
Vel Head (ft)2.94 Wt. n-Val. 0.035
W.S. Elev (ft)5406.19 Reach Len. (ft)1192.00 1932.78 2126.00
Crit W.S. (ft)5406.19 Flow Area (sq ft) 2538.02
E.G. Slope (ft/ft) 0.010048 Area (sq ft) 2538.02
Q Total (cfs)34900.00 Flow (cfs) 34900.00
Top Width (ft)435.29 Top Width (ft) 435.29
Vel Total (ft/s)13.75 Avg. Vel. (ft/s) 13.75
Max Chl Dpth (ft)6.19 Hydr. Depth (ft) 5.83
Conv. Total (cfs) 348159.0 Conv. (cfs) 348159.0
Length Wtd. (ft) 1822.27 Wetted Per. (ft) 436.98
Min Ch El (ft)5400.00 Shear (lb/sq ft) 3.64
Alpha 1.00 Stream Power (lb/ft s) 50.10
Frctn Loss (ft)6.32 Cum Volume (acre-ft) 2111.11 1126.78 45.87
C & E Loss (ft)1.27 Cum SA (acres)692.07 286.47 11.90
Plan: FwayM1 Colorado River Site 1 RS: 27494.84 Profile: PF 1
E.G. Elev (ft)5400.76 Element Left OB Channel Right OB
Vel Head (ft)0.39 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5400.36 Reach Len. (ft)1158.00 1239.23 1263.00
Crit W.S. (ft) Flow Area (sq ft)4861.16 4177.35 18.47
E.G. Slope (ft/ft) 0.001737 Area (sq ft)4861.16 4177.35 18.47
Q Total (cfs)34900.00 Flow (cfs)10420.06 24453.99 25.95
Top Width (ft)1988.92 Top Width (ft)1287.13 693.72 8.07
Vel Total (ft/s)3.85 Avg. Vel. (ft/s)2.14 5.85 1.41
Max Chl Dpth (ft)6.45 Hydr. Depth (ft)3.78 6.02 2.29
Conv. Total (cfs) 837333.6 Conv. (cfs)250001.9 586709.1 622.6
Length Wtd. (ft) 1214.72 Wetted Per. (ft)1289.08 694.24 9.23
Min Ch El (ft)5394.00 Shear (lb/sq ft)0.41 0.65 0.22
Alpha 1.71 Stream Power (lb/ft s)0.88 3.82 0.30
Frctn Loss (ft)2.95 Cum Volume (acre-ft) 2044.60 977.80 45.42
C & E Loss (ft)0.03 Cum SA (acres)674.46 261.42 11.70
Floodplain Engineering Report - Appendix A May 2022
A-31
Plan: FwayM1 Colorado River Site 1 RS: 26255.61 Profile: PF 1
E.G. Elev (ft)5397.78 Element Left OB Channel Right OB
Vel Head (ft)0.71 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5397.07 Reach Len. (ft)1050.00 1036.15 981.00
Crit W.S. (ft) Flow Area (sq ft)4547.55 3056.94
E.G. Slope (ft/ft) 0.003637 Area (sq ft)4547.55 3056.94
Q Total (cfs)34900.00 Flow (cfs)10650.84 24249.15
Top Width (ft)2396.30 Top Width (ft)1836.46 559.84
Vel Total (ft/s)4.59 Avg. Vel. (ft/s)2.34 7.93
Max Chl Dpth (ft)6.54 Hydr. Depth (ft)2.48 5.46
Conv. Total (cfs) 578683.9 Conv. (cfs)176603.8 402080.1
Length Wtd. (ft) 1035.12 Wetted Per. (ft)1837.77 560.58
Min Ch El (ft)5390.53 Shear (lb/sq ft)0.56 1.24
Alpha 2.16 Stream Power (lb/ft s)1.32 9.82
Frctn Loss (ft)4.10 Cum Volume (acre-ft) 1919.54 874.90 45.16
C & E Loss (ft)0.05 Cum SA (acres)632.94 243.59 11.58
Plan: FwayM1 Colorado River Site 1 RS: 25219.46 Profile: PF 1
E.G. Elev (ft)5393.63 Element Left OB Channel Right OB
Vel Head (ft)0.54 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5393.09 Reach Len. (ft)1167.00 1118.45 1053.00
Crit W.S. (ft) Flow Area (sq ft)3947.71 2196.65 1915.77
E.G. Slope (ft/ft) 0.004325 Area (sq ft)3947.71 2196.65 1915.77
Q Total (cfs)34900.00 Flow (cfs)11015.23 17142.44 6742.32
Top Width (ft)2481.76 Top Width (ft)1534.07 469.76 477.93
Vel Total (ft/s)4.33 Avg. Vel. (ft/s)2.79 7.80 3.52
Max Chl Dpth (ft)7.09 Hydr. Depth (ft)2.57 4.68 4.01
Conv. Total (cfs) 530694.1 Conv. (cfs)167499.1 260670.3 102524.6
Length Wtd. (ft) 1129.40 Wetted Per. (ft)1535.65 470.06 478.59
Min Ch El (ft)5388.00 Shear (lb/sq ft)0.69 1.26 1.08
Alpha 1.85 Stream Power (lb/ft s)1.94 9.85 3.80
Frctn Loss (ft)3.39 Cum Volume (acre-ft) 1817.15 812.41 23.58
C & E Loss (ft)0.07 Cum SA (acres)592.32 231.35 6.20
Plan: FwayM1 Colorado River Site 1 RS: 24101.01 Profile: PF 1
E.G. Elev (ft)5390.18 Element Left OB Channel Right OB
Vel Head (ft)0.31 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5389.86 Reach Len. (ft)1473.00 1412.79 1111.00
Crit W.S. (ft) Flow Area (sq ft)6950.58 3812.73 3.74
E.G. Slope (ft/ft) 0.002201 Area (sq ft)6950.58 3812.73 3.74
Q Total (cfs)34900.00 Flow (cfs)13817.05 21079.60 3.36
Top Width (ft)3290.17 Top Width (ft)2463.58 822.80 3.79
Vel Total (ft/s)3.24 Avg. Vel. (ft/s)1.99 5.53 0.90
Max Chl Dpth (ft)6.11 Hydr. Depth (ft)2.82 4.63 0.99
Conv. Total (cfs) 743889.4 Conv. (cfs)294508.8 449309.1 71.5
Length Wtd. (ft) 1444.67 Wetted Per. (ft)2464.64 824.45 4.37
Min Ch El (ft)5383.97 Shear (lb/sq ft)0.39 0.64 0.12
Alpha 1.91 Stream Power (lb/ft s)0.77 3.51 0.11
Frctn Loss (ft)4.42 Cum Volume (acre-ft) 1671.17 735.26 0.38
C & E Loss (ft)0.00 Cum SA (acres)538.77 214.75 0.38
Floodplain Engineering Report - Appendix A May 2022
A-32
Plan: FwayM1 Colorado River Site 1 RS: 22688.22 Profile: PF 1
E.G. Elev (ft)5385.76 Element Left OB Channel Right OB
Vel Head (ft)0.33 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5385.43 Reach Len. (ft)1763.00 1957.55 2135.00
Crit W.S. (ft) Flow Area (sq ft)8428.58 1688.44 1.39
E.G. Slope (ft/ft) 0.004527 Area (sq ft)8428.58 1688.44 1.39
Q Total (cfs)34900.00 Flow (cfs)23165.64 11732.96 1.40
Top Width (ft)3654.56 Top Width (ft)3208.84 444.13 1.59
Vel Total (ft/s)3.45 Avg. Vel. (ft/s)2.75 6.95 1.00
Max Chl Dpth (ft)5.43 Hydr. Depth (ft)2.63 3.80 0.88
Conv. Total (cfs) 518707.7 Conv. (cfs)344303.6 174383.3 20.8
Length Wtd. (ft) 1819.93 Wetted Per. (ft)3211.26 444.98 2.37
Min Ch El (ft)5380.75 Shear (lb/sq ft)0.74 1.07 0.17
Alpha 1.79 Stream Power (lb/ft s)2.04 7.45 0.17
Frctn Loss (ft)6.45 Cum Volume (acre-ft) 1411.14 646.05 0.32
C & E Loss (ft)0.04 Cum SA (acres)442.86 194.21 0.31
Plan: FwayM1 Colorado River Site 1 RS: 20730.67 Profile: PF 1
E.G. Elev (ft)5379.28 Element Left OB Channel Right OB
Vel Head (ft)0.19 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5379.09 Reach Len. (ft)1430.00 1332.44 1200.00
Crit W.S. (ft) Flow Area (sq ft)9719.50 1675.51 1.65
E.G. Slope (ft/ft) 0.002846 Area (sq ft)9719.50 1675.51 1.65
Q Total (cfs)34900.00 Flow (cfs)26213.27 8685.40 1.33
Top Width (ft)3504.97 Top Width (ft)3018.75 483.75 2.47
Vel Total (ft/s)3.06 Avg. Vel. (ft/s)2.70 5.18 0.80
Max Chl Dpth (ft)7.09 Hydr. Depth (ft)3.22 3.46 0.67
Conv. Total (cfs) 654172.5 Conv. (cfs)491346.7 162800.9 24.9
Length Wtd. (ft) 1408.01 Wetted Per. (ft)3020.93 483.92 2.75
Min Ch El (ft)5374.88 Shear (lb/sq ft)0.57 0.62 0.11
Alpha 1.30 Stream Power (lb/ft s)1.54 3.19 0.09
Frctn Loss (ft)3.62 Cum Volume (acre-ft) 1043.89 570.47 0.24
C & E Loss (ft)0.02 Cum SA (acres)316.84 173.36 0.21
Plan: FwayM1 Colorado River Site 1 RS: 19398.23 Profile: PF 1
E.G. Elev (ft)5375.64 Element Left OB Channel Right OB
Vel Head (ft)0.12 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5375.52 Reach Len. (ft)1603.00 1689.97 1773.00
Crit W.S. (ft) Flow Area (sq ft)11872.55 1707.28 1.89
E.G. Slope (ft/ft) 0.002332 Area (sq ft)11872.55 1707.28 1.89
Q Total (cfs)34900.00 Flow (cfs)27855.12 7043.32 1.56
Top Width (ft)4022.92 Top Width (ft)3423.79 597.33 1.80
Vel Total (ft/s)2.57 Avg. Vel. (ft/s)2.35 4.13 0.83
Max Chl Dpth (ft)7.52 Hydr. Depth (ft)3.47 2.86 1.05
Conv. Total (cfs) 722726.4 Conv. (cfs)576837.4 145856.6 32.3
Length Wtd. (ft) 1627.56 Wetted Per. (ft)3428.88 598.09 2.61
Min Ch El (ft)5372.00 Shear (lb/sq ft)0.50 0.42 0.11
Alpha 1.19 Stream Power (lb/ft s)1.18 1.71 0.09
Frctn Loss (ft)3.64 Cum Volume (acre-ft) 689.47 518.73 0.19
C & E Loss (ft)0.01 Cum SA (acres)211.09 156.82 0.15
Floodplain Engineering Report - Appendix A May 2022
A-33
Plan: FwayM1 Colorado River Site 1 RS: 17708.26 Profile: PF 1
E.G. Elev (ft)5372.00 Element Left OB Channel Right OB
Vel Head (ft)0.20 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5371.79 Reach Len. (ft)2036.00 1873.91 2008.00
Crit W.S. (ft) Flow Area (sq ft)8368.25 2601.75 2.56
E.G. Slope (ft/ft) 0.002145 Area (sq ft)8368.25 2601.75 2.56
Q Total (cfs)34900.00 Flow (cfs)22240.22 12657.77 2.01
Top Width (ft)2550.16 Top Width (ft)1880.86 667.70 1.60
Vel Total (ft/s)3.18 Avg. Vel. (ft/s)2.66 4.87 0.79
Max Chl Dpth (ft)7.76 Hydr. Depth (ft)4.45 3.90 1.60
Conv. Total (cfs) 753635.3 Conv. (cfs)480258.2 273333.6 43.4
Length Wtd. (ft) 1933.26 Wetted Per. (ft)1882.44 668.37 3.57
Min Ch El (ft)5366.00 Shear (lb/sq ft)0.60 0.52 0.10
Alpha 1.29 Stream Power (lb/ft s)1.58 2.54 0.08
Frctn Loss (ft)5.87 Cum Volume (acre-ft) 317.04 435.14 0.10
C & E Loss (ft)0.03 Cum SA (acres)113.49 132.29 0.08
Plan: FwayM1 Colorado River Site 1 RS: 15834.35 Profile: PF 1
E.G. Elev (ft)5366.09 Element Left OB Channel Right OB
Vel Head (ft)0.50 Wt. n-Val. 0.070 0.035
W.S. Elev (ft)5365.59 Reach Len. (ft)2339.00 1918.66 1085.00
Crit W.S. (ft) Flow Area (sq ft)1638.93 5324.94
E.G. Slope (ft/ft) 0.004620 Area (sq ft)1638.93 5324.94
Q Total (cfs)34900.00 Flow (cfs)3317.35 31582.65
Top Width (ft)2814.29 Top Width (ft)1009.03 1805.26
Vel Total (ft/s)5.01 Avg. Vel. (ft/s)2.02 5.93
Max Chl Dpth (ft)3.68 Hydr. Depth (ft)1.62 2.95
Conv. Total (cfs) 513440.2 Conv. (cfs)48804.0 464636.2
Length Wtd. (ft) 1953.01 Wetted Per. (ft)1009.59 1807.21
Min Ch El (ft)5361.91 Shear (lb/sq ft)0.47 0.85
Alpha 1.28 Stream Power (lb/ft s)0.95 5.04
Frctn Loss (ft)6.10 Cum Volume (acre-ft)83.18 264.64 0.04
C & E Loss (ft)0.05 Cum SA (acres)45.95 79.09 0.05
Plan: FwayM1 Colorado River Site 1 RS: 13915.69 Profile: PF 1
E.G. Elev (ft)5359.94 Element Left OB Channel Right OB
Vel Head (ft)0.34 Wt. n-Val. 0.070 0.035 0.070
W.S. Elev (ft)5359.60 Reach Len. (ft)
Crit W.S. (ft)5358.10 Flow Area (sq ft)1459.11 6691.67 3.55
E.G. Slope (ft/ft) 0.002251 Area (sq ft)1459.11 6691.67 3.55
Q Total (cfs)34900.00 Flow (cfs)2392.54 32504.24 3.22
Top Width (ft)2492.14 Top Width (ft)702.41 1786.08 3.65
Vel Total (ft/s)4.28 Avg. Vel. (ft/s)1.64 4.86 0.91
Max Chl Dpth (ft)5.91 Hydr. Depth (ft)2.08 3.75 0.97
Conv. Total (cfs) 735527.1 Conv. (cfs)50423.4 685035.7 67.9
Length Wtd. (ft) Wetted Per. (ft)702.45 1787.14 4.16
Min Ch El (ft)5353.69 Shear (lb/sq ft)0.29 0.53 0.12
Alpha 1.21 Stream Power (lb/ft s)0.48 2.56 0.11
Frctn Loss (ft) Cum Volume (acre-ft)
C & E Loss (ft) Cum SA (acres)
Floodplain Engineering Report - Appendix A May 2022
A-34
01000200030004000535053555360536553705375538053855390Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1WS PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1Crit PF 2 - FwayM1Crit PF 1 - FwayM1Crit PF 1 - Existing2GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-35
05001000150020002500300035005404540654085410541254145416541854205422Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1WS PF 2 - FwayM1EG PF 1 - FwayM1EG PF 1 - Existing2WS PF 1 - FwayM1WS PF 1 - Existing2GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-36
0200400600800100012001400540054025404540654085410541254145416Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 1 - Existing2EG PF 1 - FwayM1EG PF 2 - FwayM1WS PF 1 - FwayM1WS PF 1 - Existing2WS PF 2 - FwayM1Crit PF 1 - Existing2Crit PF 1 - FwayM1Crit PF 2 - FwayM1GroundBank Sta.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-37
020040060080010001200140054005405541054155420Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 I-70 Bridge over Colorado River (ft) (ft)LegendEG PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 2 - FwayM1WS PF 1 - FwayM1WS PF 1 - Existing2Crit PF 1 - Existing2Crit PF 1 - FwayM1Crit PF 2 - FwayM1GroundBank Sta.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-38
02004006008001000120014005400540254045406540854105412541454165418Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 I-70 Bridge over Colorado River (ft) (ft)LegendEG PF 1 - Existing2EG PF 1 - FwayM1EG PF 2 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1WS PF 2 - FwayM1Crit PF 1 - FwayM1Crit PF 2 - FwayM1Crit PF 1 - Existing2GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-39
020040060080010001200140054005402540454065408541054125414Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 1 - Existing2EG PF 1 - FwayM1EG PF 2 - FwayM1WS PF 1 - FwayM1Crit PF 1 - FwayM1WS PF 2 - FwayM1Crit PF 2 - FwayM1Crit PF 1 - Existing2WS PF 1 - Existing2GroundBank Sta.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-40
050010001500200025005390540054105420543054405450Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1WS PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-41
0500100015002000250030003500539054005410542054305440Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 2 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-42
01000200030004000538053905400541054205430Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 2 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-43
010002000300040005000538053905400541054205430Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1WS PF 2 - FwayM1EG PF 1 - FwayM1EG PF 1 - Existing2WS PF 1 - FwayM1WS PF 1 - Existing2GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-44
0100020003000400050006000535053605370538053905400541054205430Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1WS PF 2 - FwayM1EG PF 1 - FwayM1EG PF 1 - Existing2WS PF 1 - Existing2WS PF 1 - FwayM1GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-45
0100020003000400050006000534053605380540054205440Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1WS PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-46
0100020003000400050006000700053605370538053905400541054205430Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1WS PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-47
01000200030004000500060007000535053605370538053905400541054205430Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1WS PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-48
010002000300040005000536053655370537553805385Colorado River Plan: 1) Existing2 5/14/2020 2) FwayM1 9/14/2020 (ft) (ft)LegendEG PF 2 - FwayM1EG PF 1 - Existing2EG PF 1 - FwayM1WS PF 1 - Existing2WS PF 1 - FwayM1WS PF 2 - FwayM1GroundBank StaEncroachment.07.035.07Floodplain Engineering Report - Appendix AMay 2022A-49
Revised Floodplain Development Permit Narrative for Rifle Pit #1 August 2022
C
Attachment C
Warranty Deed
Title Agreement
Statement of Authority
Certification of Mineral Ownership Research
Neighbor Mailing List
Letter of Authorization
Point of Contact at IHC-Scott
LAND TITLE GUARANTEE COMPANY
Date: July 28, 2022
Subject: Attached Title Policy/Guarantee
Enclosed please find your product insuring the property located at MALONE RANCH, SILT, CO 81650.
If you have any inquiries or require further assistance, please contact George Rietsch at (303) 850-4151 or
grietsch@ltgc.com
Chain of Title Documents:
Garfield county recorded 09/13/2019 under reception no.
925393
Property Information Binder
CONDITIONS AND STIPULATIONS
1. Definition of Terms
The following terms when used in this Binder mean:
2. Exclusions from Coverage of this Binder
The company assumes no liability including cost of defense by reason of the following:
3. Prosecution of Actions
1. The Company shall have the right at its own costs to institute and prosecute any action or proceeding
or do any other act which in its opinion may be necessary or desirable to establish or confirm the
matters herein assured; and the Company may take any appropriate action under the terms of this
Binder, whether or not it shall be liable thereunder and shall not thereby concede liability or waive any
provision hereof.
2. In all cases where the Company does not institute and prosecute any action or proceeding, the
Assured shall permit the Company to use, at its option, the name of the Assured for this purpose.
Whenever requested by the Company, the Assured shall give the Company all reasonable aid in
prosecuting such action or proceeding, and the Company shall reimburse the Assured for any expense
so incurred.
4. Notice of Loss - Limitation of Action
A statement in writing of any loss or damage for which it is claimed the Company is liable under this Binder
shall be furnished to the Company within sixty days after such loss or damage shall have been determined,
and no right of action shall accrue to the Assured under this Binder until thirty days after such statement shall
have been furnished, and no recovery shall be had by the Assured under this Binder unless action shall be
commenced thereon with two years after expiration of the thirty day period. Failure to furnish the statement
of loss or damage or to commence the action within the time herinbefore specified, shall be conclusive bar
against maintenance by the Assured of any action under this Binder.
5. Option to Pay, Settle or Compromise Claims
"Land": The land described, specifically or by reference, in this Binder and improvements affixed
thereto which by law constitute real property;
(a)
"Public Records"; those records which impart constructive notice of matters relating to said land;(b)
"Date": the effective date;(c)
"the Assured": the party or parties named as the Assured in this Binder, or in a supplemental writing
executed by the Company;
(d)
"the Company" means Old Republic National Title Insurance Company, a Minnesota stock company.(e)
Taxes or assessments which are not shown as existing liens by the records of any taxing authority that
levies taxes or assessments on real property or by the Public Records; taxes and assessments not yet
due or payable and special assessments not yet certified to the Treasurer's office.
(a)
Unpatented mining claims; reservations or exceptions in patents or in Acts authorizing the issuance
thereof; water rights, claims or title to water.
(b)
Title to any property beyond the lines of the Land, or title to streets, roads, avenues, lanes, ways or
waterways on which such land abuts, or the right to maintain therein vaults, tunnels, ramps, or any
other structure or improvement; or any rights or easements therein unless such property, rights or
easements are expressly and specifically set forth in said description.
(c)
Mechanic's lien(s), judgment(s) or other lien(s).(d)
Defects, liens, encumbrances, adverse claims or other matters: (a) created, suffered or agreed to by
the Assured;(b) not known to the Company, not recorded in the Public Records as of the Date, but
known to the Assured as ofthe Date; or (c) attaching or creating subsequent to the Date.
(e)
The Company shall have the option to pay, settle or compromise for or in the name of the Assured any claim
which could result in loss to the Assured within the coverage of this Binder, or to pay the full amount of this
Binder. Such payment or tender of payment of the full amount of the Binder shall terminate all liability of the
Company hereunder.
6. Limitation of Liability - Payment of Loss
7. Subrogation Upon Payment or Settlement
Whenever the Company shall have settled a claim under this Binder, all right of subrogation shall vest in the
Company unaffected by any act of the Assured, and it shall be subrogated to and be entitled to all rights and
remedies which the Assured would have had against any person or property in respect to the claim had this
Binder not been issued. If the payment does not cover the loss of the Assured, the Company shall be
subrogated to the rights and remedies in the proportion which the payment bears to the amount of said loss.
The Assured, if requested by the Company, shall transfer to the Company all rights and remedies against any
person or property necessary in order to perfect the right of subrogation, and shall permit the Company to use
the name of the Assured in any transaction or litigation involving the rights or remedies.
8. Binder Entire Contract
Any action or actions or rights of action that the Assured may have or may bring against the Company arising
out of the subject matter hereof must be based on the provisions of this Binder. No provision or condition of
this Binder can be waived or changed except by a writing endorsed or attached hereto signed by the President,
a Vice President, the Secretary, an Assistant Secretary or other validating officer of the Company.
9. Notices. Where Sent
All notices required to be given the Company and any statement in writing required to be furnished the
Company shall be addressed to it at 400 Second Avenue South, Minneapolis, Minnesota 55401, (612) 371-
1111.
10. Arbitration
Unless prohibited by applicable law, either the Company or the insured may demand arbitration pursuant to the
Title Insurance Arbitration Rules of the American Arbitration Association.
ANTI-FRAUD STATEMENT: Pursuant to CRS 10-1-128(6)(a), it is unlawful to knowingly provide false,
incomplete or misleading facts or information to an insurance company for the purpose of defrauding or
attempting to defraud the company. Penalties may include imprisonment, fines, denial of insurance and civil
damages. Any insurance company or agent of an insurance company who knowingly provides false,
incomplete, or misleading facts or information to a policyholder or claimant for the purpose of defrauding or
The liability of the Company under this Binder shall be limited to the amount of actual loss sustained by
the Assured because of reliance upon the assurances herein set forth, but in no event shall the liability
exceed the amount of the liability stated on the face page hereof.
(a)
The Company will pay all costs imposed upon the Assured in litigation carried on by the Company for
the Assured, and all costs and attorneys' fees in litigation carried on by the Assured with the written
authorization of the Company.
(b)
No claim for loss or damages shall arise or be maintainable under this Binder (1) if the Company after
having received notice of any alleged defect, lien or encumbrance not shown as an Exception or
excluded herein removes such defect, lien or encumbrance within a reasonable time after receipt of
such notice, or (2) for liability voluntarily assumed by the Assured in settling any claim or suit without
written consent of the Company.
(c)
All payments under this Binder, except for attorney's fees as provided for in paragraph 6(b) thereof,
shall reduce the amount of the liability hereunder pro tanto, and no payment shall be made without
producing this Binder or an acceptable copy thereof for endorsement of the payment unless the Binder
be lost or destroyed, in which case proof of the loss or destruction shall be furnished to the satisfaction
of the Company.
(d)
When liability has been definitely fixed in accordance with the conditions of this Binder, the loss or
damage shall be payable within thirty days thereafter.
(e)
attempting to defraud the policyholder or claimant with regard to a settlement or award payable from insurance
proceeds shall be reported to the Colorado division of insurance within the department of regulatory agencies.
This anti-fraud statement is affixed and made a part of this policy.
Copyright 2006-2022 American Land Title Association. All rights reserved. The use of this form is restricted to
ALTA licensees and ALTA members in good standing as of the date of use. All other uses are prohibited.
Reprinted under license from the American Land Title Association.
Issued by:
Land Title Guarantee Company
3033 East First Avenue Suite 600
Denver, Colorado 80206
303-321-1880
Craig B. Rants, Senior Vice President
Liability:$50,000.00
Fee:$500.00
Subject to the exclusions from coverage, the limits of liability and other provisions of the Conditions and
Stipulations hereto annexed and made a part of this Binder,
OLD REPUBLIC NATIONAL TITLE INSURANCE COMPANY a Corporation, herein called the Company,
GUARANTEES
IHC SCOTT, INC., A MICHIGAN CORPORATION
Herein called the Assured, against loss, not exceeding the liability amount stated above, which the assured
shall sustain by reason of any incorrectness in the assurance which the Company hereby gives that,
according to the public records as of
July 08, 2022 at 5:00 P.M.
1. Title to said estate or interest at the date hereof is vested in:
IHC SCOTT, INC., A MICHIGAN CORPORATION SUCCESSOR BY MERGER TO SCOTT CONTRACTING, INC.
A COLORADO CORPORATION
2. The estate or interest in the land hereinafter described or referred to covered by this Binder :
A FEE SIMPLE
3. The Land referred to in this Binder is described as follows:
TOWNSHIP 6 SOUTH, RANGE 92 WEST OF THE 6TH P.M.,
SECTION 8: S1/2 SW 1/4
SECTION 17: NE 1/4 NW 1/4 AND NW 1/4 NW 1/4
LESS AND EXCEPTING THE FOLLOWING TRACTS OF LAND PREVIOUSLY CONVEYED AND RECORDED:
1. A TRACT OF LAND LOCATED IN THE SW 1/4 SW 1/4 SECTION 8, AND THE NW1/4 NW 1/4 SECTION 17,
CONVEYED BY GEORGE YULE BY WARRANTY DEED RECORDED APRIL 17, 1893 IN BOOK 32 AT PAGE 425.
2. A TRACT OF LAND LYING IN THE SE CORNER OF THE NE 1/4 NW 1/4 OF SECTION 17 AS GRANTED TO
SCHOOL DISTRICT 27 OF GARFIELD COUNTY BY WARRANTY DEED DATED OCTOBER 10, 1891,
RECORDED OCTOBER 12, 1891 IN BOOK 25 AT PAGE 188.
Old Republic National Title Insurance Company
PROPERTY INFORMATION BINDER
Order Number: ABS63019055 Policy No.: PIB63019055.22486671
3. A TRACT OF LAND LYING IN THE SE 1/4 SW 1/4 SECTION 8, AND N 1/2 NW 1/4 SECTION 17 COMPRISING
INTERSTATE HIGHWAY 70 R.O.W., INCLUDING:
THAT PART OF THE N 1/2 NW 1/4 SECTION 17 CONVEYED TO THE BOARD OF COUNTY COMMISSIONERS
OF THE COUNTY OF GARFIELD, STATE OF COLORADO AND STATE DEPARTMENT OF HIGHWAYS,
DIVISION OF HIGHWAYS, STATE OF COLORADO BY COURT ORDER RECORDED FEBRUARY 24, 1977 IN
BOOK 493 AT PAGE 768.
4. THAT PORTION OF THE NE1/4NW1/4 AND NW1/4NW1/4 OF SECTION 17, TOWNSHIP 6 SOUTH, RANGE 92
WEST, SITUATE SOUTHERLY OF THE INTERSTATE HIGHWAY 70 RIGHT OF WAY, AS CONVEYED TO
JACQUE COUEY BURRIS BY SPECIAL WARRANTY DEED RECORDED OCTOBER 4, 1991 IN BOOK 814 AT
PAGE 812.
COUNTY OF GARFIELD,
STATE OF COLORADO.
4. The following documents affect the land:
1. ANY AND ALL RIGHTS OF A DITCH COMPANY RELATING TO THE LAST CHANCE DITCH TRAVERSING
SUBJECT PROPERTY, INCLUDING BUT NOT LIMITED TO DITCH MAINTENANCE AND ACCESS RIGHTS
TO LANDS ADJOINING THE DITCH OR CANAL.
2. NOTWITHSTANDING THE INSURING CLAUSES OF THE POLICY, THE COMPANY DOES NOT INSURE
AGAINST LOSS OR DAMAGE BY REASON OF A LACK OF A RIGHT OF PHYSICAL ACCESS TO AND FROM
THE LAND.
NOTE: ACCESS TO THE SUBJECT PROPERTY IS LIMITED TO THE TERMS, CONDITIONS AND
PROVISIONS OF COLORADO DEPARTMENT OF TRANSPORTATION ACCESS PERMIT NO. 320024
3. RIGHT OF THE PROPRIETOR OF A VEIN OR LODE TO EXTRACT AND REMOVE HIS ORE THEREFROM,
SHOULD THE SAME BE FOUND TO PENETRATE OR INTERSECT THE PREMISES HEREBY GRANTED,
AND A RIGHT OF WAY FOR DITCHES OR CANALS CONSTRUCTED BY THE AUTHORITY OF THE UNITED
STATES, AS RESERVED IN UNITED STATES PATENT RECORDED MARCH 05, 1906 IN BOOK 56 AT PAGE
537.
4. RESERVATION OF ONE-HALF INTEREST IN ALL OIL, GAS AND OTHER MINERALS AS EVIDENCED IN
INSTRUMENT RECORDED MARCH 27, 1972 IN BOOK 428 AT PAGE 459, AND ANY AND ALL
ASSIGNMENTS THEREOF OR INTERESTS THEREIN.
5. ALL OIL, GAS, HYDROCARBONS AND OTHER MINERALS, TOGETHER WITH SO MUCH OF THE
SURFACE AS MAY BE NECESSARY FOR THE CONVENIENT MINING OR EXTRACTION OF SAME, AND
TOGETHER, FURTHER, THE RIGHT OF INGRESS AND EGRESS FOR THE PURPOSES OF PROSPECTING
FOR, DEVELOPING AND PRODUCING SAME, AS RESERVED IN INSTRUMENTS RECORDED FEBRUARY
13, 1973 IN BOOK 440 AT PAGE 469, AND ANY AND ALL ASSIGNMENTS THEREOF OR INTERESTS
THEREIN.
6. NO RIGHT OR RIGHTS OF ACCESS TO AND FROM THE HIGHWAY AS EVIDENCED IN RULE AND ORDER
RECORDED FEBRUARY 24, 1977 IN BOOK 493 AT PAGE 768.
NOTE: ACCESS TO THE SUBJECT PROPERTY IS LIMITED TO THE TERMS, CONDITIONS AND
PROVISIONS OF COLORADO DEPARTMENT OF TRANSPORTATION ACCESS PERMIT NO. 320024
7. OIL AND GAS LEASE RECORDED NOVEMBER 02, 1982, IN BOOK 612 AT PAGE 973, AND ANY AND ALL
ASSIGNMENTS THEREOF OR INTERESTS THEREIN.
Old Republic National Title Insurance Company
PROPERTY INFORMATION BINDER
Order Number: ABS63019055 Policy No.: PIB63019055.22486671
8. RESERVATION OF ALL OIL SHALE, KEROGEN, SHALE OIL, COAL, OIL, GAS, FISSIONABLE MATERIAL AN
ALL OTHER MINERALS OF ANY KIND OR NATURE AS EVIDENCED BY SPECIAL WARRANTY DEED
RECORDED NOVEMBER 03, 1989 IN BOOK 766 AT PAGE 317, AND ANY AND ALL ASSIGNMENTS
THEREOF OR INTERESTS THEREIN.
9. TERMS, CONDITIONS, PROVISIONS, BURDENS AND OBLIGATIONS AS SET FORTH IN WATER WELL
SHARING AGREEMENT RECORDED JUNE 05, 2009 UNDER RECEPTION NO. 769089.
10. ANY INCREASE OR DECREASE IN THE AREA OF THE LAND AND ANY ADVERSE CLAIM TO ANY
PORTION OF THE LAND WHICH HAS BEEN CREATED BY OR CAUSED BY ACCRETION OR RELICTION,
WHETHER NATURAL OR ARTIFICIAL; AND THE EFFECT OF THE GAIN OR LOSS OF AREA BY
ACCRETION OR RELICTION UPON THE MARKETABILITY OF THE TITLE OF THE LAND.
NOTE: THIS BINDER DOES NOT REFLECT THE STATUS OF TITLE TO WATER RIGHTS OR
REPRESENTATION OF SAID RIGHTS, RECORDED OR NOT.
NOTE: THIS COMMITMENT IS NOT A REPORT OR REPRESENTATION AS TO MINERAL INTERESTS, AND
SHOULD NOT BE USED, OR RELIED UPON, IN CONNECTION WITH THE NOTICE REQUIREMENTS THAT
ARE SET FORTH IN CRS 24-65.5-103.
NOTE: ADDITIONAL UPDATES TO THE EFFECTIVE DATE OF THE BINDER MAY BE REQUESTED BY THE
PROPOSED INSURED. ONE UPDATE IS INCLUDED WITH THIS BINDER AT NO ADDITIONAL COST. ANY
ADDITIONAL UPDATES WILL BE ISSUED AT THE COST OF $125 PER UPDATE. FOR EACH UPDATE
PROVIDED, A REVISED BINDER WILL BE ISSUED SHOWING A NEW EFFECTIVE DATE AND ANY
MATTERS RECORDED SINCE THE EFFECTIVE DATE OF THE PREVIOUS BINDER.
THIS PRODUCT WILL ONLY BE UPDATED FOR 24 MONTHS FOLLOWING THE EFFECTIVE DATE OF THE
ORIGINAL BINDER.
Old Republic National Title Insurance Company
PROPERTY INFORMATION BINDER
Order Number: ABS63019055 Policy No.: PIB63019055.22486671
c@ Garfield County STATEMENT OF AUTHORITY Pursuant to C.R.S. §38-30-172, the undersigned executes this Statement of Authority on behalf of IHC Scott, Inc. (dba Scott Contracting, Inc.) a Colorado Corporation (corporation, limited liability company, general partnership, registered limited liability partnership, registered limited liability limited partnership, limited partnership association, government agency, trust or other), an entity other than an individual, capable of holding title to real property (the "Entity"), and states as follows: The name of the Entity is IHC Scott, Inc. (dba Scott Contracting, Inc.) and is formed under the laws of _C_o_lo_ra_d_o _____________________ _ The mailing address for the Entity is 9200 E. Minera! Avenue, #-400, Centennial, CO 80112 The name and/or position of the person authorized to execute instruments conveying, encumbering, or -otherwise affecting title to real property on behalf of the Entity is Terri Priday, VP of Administration The limitations upon the authority of the person named above or holding the position described above to bind the Entity are as follows (if no limitations, insert "None"): _N_o_ne ___________ _ Other matters concerning the manner in which the Entity deals with any interest in real property are (if no other matter, leave this section blank): _____________________ _ EXECUTED this s--day of __ M_t,._uc;-------~ 20 7,, 2-. STATE OF ll,.,. )SS. COUNTY OF _CJ'1-'----'.--Jv_......;{__;c___~l The foregoing instrume)ilt was acknowledged before me this "S day of MOA-\ 20 2 Z. by Tew ~~ell.a,., ,on behalf of T\::';-C.. Sa+-+--t...c. ,a Mlc..k-~ Co:r:w~ w;toess my haod aod off~al seaJ, 0 , ,f' f2_.c ~ ~ My comm1ss1on expires: f.!.L tJ,{A 0\. ()' ,.26cr-r rfr~ if Iv t [SEAL] j (Date) / (Notary Public) PATRICIA PARRINO NOTARY PUBLIC STATE OF COLORADO NOTARY ID 20104015234 MY COMMISSION EXPIRES MAY 28, 2024
6/18/2020 Garfield County Land Explorer
1/1
Garfield County Land Explorer
Parcel Physical Address Owner Account
Num Mailing Address
217907100292 Not available SILT ISLAND PARK LLC R024363 2311 MEADOWLARK LANE GLENWOOD SPRINGS, CO
81601
217908100527 Not available SILT SHIDELEROSA LLLP R230963 1411 COUNTY ROAD 316 SILT, CO 81652
217908200101 6073 346 COUNTY RD
SILT
COLORADO RIVER RANCH,
LLC R023384 10 MUSTANG DRIVE NEW CASTLE, CO 81647
217908300102 Not available SILT
REX ROBINSON RANCH LLC
&R023138 5473 N CRESCENT RIDGE DRIVE TUCSON, AZ 85718
217908300103 Not available SILT SCOTT CONTRACTING INC R023405
9200 E MINERAL AVENUE #400 CENTENNIAL, CO
80112
ROW Not available null
Revised Floodplain Development Permit Narrative for Rifle Pit #1 August 2022
D
Attachment D
CDOT Access Permit #320024
PROJECT LOCATION MAP
Section 8 & 17, Township 6 South, Range 92 West 6th Prime
Meridian
SCOTT CONTRACTING INC.
CDOT ACCESS PERMIT #320024
RIFLE GRAVEL PIT NO. 1
JANUARY 2021
CONSTRUCTION PLANS
N.T.S.
Drawing File Name: RiflePit-Rdwy-Admin 118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Project Engineer:
PROJECT STARTED: / /
Comments:
Project No./Code
1
--
--
Sheet Number
No Revisions:
Revised:
Void:
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/2021
Last Modification Date: 1/26/2021
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
As Constructed
Resident Engineer:
Contract Information
Contractor:
ACCEPTED: / /Scale: As Shown
Quality Control:
SHEET NO.INDEX OF SHEETS
1 TITLE SHEET
2 STANDARD PLANS
3-5 GENERAL NOTES
6 SUMMARY OF APPROXIMATE QUANTITIES (SAQ)
7 TYPICAL SECTIONS
8 DETAILS
9-11 GEOMETRY PLAN
12-16 PLAN & PROFILE
17 DRIVEWAY PLAN AND PROFILE
18-20 TRAFFIC CONTROL
21-25 STORM WATER MANAGEMENT PLAN (SWMP)
26-28 EROSION CONTROL
29 SIGNING & STRIPING
30-31 CROSS SECTIONS
32 WB-50 TURNING MOVEMENT
TABULATION OF LENGTH
01-27-21
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
STANDARD PLANS
ADMIN 2 of 6
Project No./Code
2
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Admin
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 1/26/2021
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
GENERAL NOTES (1)
ADMIN 3 of 6
Project No./Code
3
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Admin
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 1/26/2021
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
GENERAL NOTES (2)
ADMIN 4 of 6
Project No./Code
4
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Admin
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 1/26/2021
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
“”
”
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
GENERAL NOTES (3)
---- of --
Project No./Code
5
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Admin
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 1/26/2021
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
SAQ
SAQ 1 of 1
Project No./Code
6
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Admin
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 1/26/2021
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
TYPICAL SECTIONS
ADMIN 5 of 6
Project No./Code
7
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Admin
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 1/26/2021
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
DETAILS
ADMIN 6 of 6
Project No./Code
8
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Admin
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 1/26/2021
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
Graphic Scale
In Feet: 1" = 100'
0 50 100 200
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
GEOMETRY PLAN (1)
GEOM 1 of 3
Project No./Code
9
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Geom
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 12/7/2020
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
Graphic Scale
In Feet: 1" = 100'
0 50 100 200
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
GEOMETRY PLAN (2)
GEOM 2 of 3
Project No./Code
10
--
--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-Geom
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 12/7/2020
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
01-27-21
Graphic Scale
In Feet: 1" = 100'
0 50 100 200
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
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CDOT ACCESS PERMIT #320024
GEOMETRY PLAN (3)
GEOM 3 of 3
Project No./Code
11
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01-27-21
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118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
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CDOT ACCESS PERMIT #320024
PLAN & PROFILE (1)
PP 1 of 5
Project No./Code
12
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01-27-21
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118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
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CDOT ACCESS PERMIT #320024
PLAN & PROFILE (2)
PP 2 of 5
Project No./Code
13
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01-27-21
Graphic Scale
In Feet: 1" = 50'
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118 West Sixth Street, Suite 200
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CDOT ACCESS PERMIT #320024
PLAN & PROFILE (3)
PP 3 of 5
Project No./Code
14
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01-27-21
Graphic Scale
In Feet: 1" = 50'
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118 West Sixth Street, Suite 200
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CDOT ACCESS PERMIT #320024
PLAN & PROFILE (4)
PP 4 of 5
Project No./Code
15
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01-27-21
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In Feet: 1" = 50'
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118 West Sixth Street, Suite 200
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CDOT ACCESS PERMIT #320024
PLAN & PROFILE (5)
PP 5 of 5
Project No./Code
16
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01-27-21
RiflePit-DwayPP118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com Engineer:Drawn By:Sheet Subset:JJLJJLStructureNumbers17____--CDOT ACCESS PERMIT #320024DRIVEWAY PLAN & PROFILESubset Sheets:No.:Code:Sheet Number:No Revisions:Revised:Void:DateCommentsInit.Rev.Computer File InformationPrint Date: 1/26/21Last Modification Date: 12/7/2020Quality Control: RNDrawing File Name:SGM Project No.: 2019-341.002Graphic ScaleIn Feet: 1" = 40'0 20 4080---Project No./CodeSheet RevisionsAutocad Ver. 2020 Scale: As Shown Units: EnglishDWAY PP1 of 1------As Constructed01-27-21
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CDOT ACCESS PERMIT #320024
TRAFFIC CONTROL (1)
TC 1 of 3
Project No./Code
18
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01-27-21
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CDOT ACCESS PERMIT #320024
TRAFFIC CONTROL (2)
TC 2 of 3
Project No./Code
19
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01-27-21
Graphic Scale
In Feet: 1" = 50'
0 25 50 100
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
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CDOT ACCESS PERMIT #320024
TRAFFIC CONTROL (3)
TC 3 of 3
Project No./Code
20
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01-27-21
118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
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Structure
Numbers
CDOT ACCESS PERMIT #320024
SWMP (1)
SWMP 1 of 5
Project No./Code
21
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Drawing File Name: RiflePit-Rdwy-SWMP
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1.SITE DESCRIPTION
The Contractor shall comply with all CDOT contractual requirements associated with the CDPS-SCP on this project. The SWMP
Administrator shall update to reflect current project site conditions.
A.PROJECT SITE LOCATION: S. Midland Ave. from 27th Street to 4-Mile Rd. Glenwood Springs, Garfield County, CO
PROJECT SITE DESCRIPTION: The project includes road reconstruction, and construction of a new access driveway on the north
side of CR 346. The existing gravel roadway will be replaced in kind with concrete pavement.
B.PROPOSED SEQUENCING FOR MAJOR ACTIVITIES:
Clearing and grubbing (driveway)
Roadway Excavation/Grading
Roadway Concrete Paving
Driveway Concrete Paving
Shouldering
Restoration
C.ACRES OF DISTURBANCE:
Total area of construction site (LOC): 4.0 acres
Total area of proposed disturbance (LDA): 3.19 acres
Total area of seeding:0.94 acres
Total area of impervious surface:2.23 acres
Total area of NEW impervious surface: 2.25 acres (0.02 acre increase)
EXISTING SOIL DATA: From USDA Web Soil Survey: Halaquepts (19.2%), Heldt Clay Loam (47.7%, Olney Loam(33.1%)
D.EXISTING VEGETATION, INCLUDING PERCENT COVER: During design the SWMP Administrator for Design in consultation with the
Engineer will determine if the SWMP Administrator for Design or the SWMP Administrator will conduct the Vegetation Transects
as outlined in Chapter 4.11.2 of the CDOT Erosion Control and Stormwater Quality Guide.
Pre-Construction Date of survey: ______________ %Density: ______________
Description of existing vegetation:
Map or table showing transect locations in SWMP notebook tab 17:
Post-Construction Date of survey: ______________ %Density: ______________
Description of existing vegetation: Date of CDPS-SCP Closure: ______________
Map or table showing transect locations in SWMP notebook tab 17:
E.POTENTIAL POLLUTANTS SOURCES: See First Construction Activities under Potential Pollutant Sources. The SWMP Administrator
shall prepare a list of all potential pollutants and their locations in accordance with subsection 107.25.
F.RECEIVING WATER:
Outfall locations: Colorado River
For a complete list of all stormwater outfalls see the drainage tabulation sheets within the plan set.
2. Names of receiving water(s) on site: NA
3. Ultimate receiving water: Colorado River
Horizontal distance nearest water of the state is from project: 3100 feet
I.NON-STORMWATER DISCHARGES: Potential dewatering* of excavations for construction of retaining walls and culvert
extensions
ALLOWABLE: Refer to CDPHE Low Risk Discharge Guidance Document of Uncontaminated Groundwater to Land
https://www.colorado.gov/pacific/sites/default/files/WQ%20LOW%20RISK%20GW.pdf
*If groundwater does not meet water quality standards for receiving water a separate CDPS Dewatering permit shall be
obtained by the Contractor from CDPHE in accordance with subsections 107.02 and 107.25.
2.SITE MAP COMPONENTS:
Pre-construction
A.PROJECT CONSTRUCTION POTENTIAL SITE BOUNDARIES Construction boundaries are generally contained within the limits of
disturbance areas. Equipment and material staging may also occur on existing graveled and disturbed areas within the
property limits. See the erosion control and site layout plans for additional information.
B.ALL AREAS OF GROUND SURFACE DISTURBANCE See the erosion control and site layout plans for limits of disturbance.
C.AREAS OF CUT AND FILL See the erosion control and site layout plans for limits of disturbance.
D.LOCATION OF ALL STRUCTURAL BMPs IDENTIFIED IN THE SWMP Structural BMP's are located on the erosion control plans.
E.LOCATION OF NON-STRUCTURAL BMPs AS APPLICABLE IN THE SWMP Non-Structural BMP's are located on the erosion control
plans.
F.SPRINGS, STREAMS, WETLANDS AND OTHER SURFACE WATER NA
G.PROTECTION OF TREES, SHRUBS, CULTURAL RESOURCES AND MATURE VEGETATION Trees and vegetation to be protected will be
as directed by CDOT and will be identified at the preconstruction conference or initial construction meeting.
H.AREAS USED FOR STORING AND STOCKPILING OF MATERIALS, STAGING AREAS (field trailer,fueling,etc) and BATCH PLANTS
These areas will be identified by the contractor and subject to approval by CDOT.
3.QUALIFIED STORMWATER MANAGERS:
A.SWMP ADMINISTRATOR FOR DESIGN:
B.SWMP Administrator for Construction: (As defined in Subsection 208) The Contractor shall designate a SWMP Administrator for
Construction upon co-permitee of the permit. The SWMP Administrator shall become the operator for the SWMP and assume
responsibility for all design changes to the SWMP implementation and maintenance in accordance to 208.03, the SWMP shall
remain the property of CDOT. The SWMP Administrator for Construction shall be responsible for implementing, maintaining
and revising SWMP, including the title and contact information. The activities and responsibilities of the SWMP Administrator
for Construction shall address all aspects of the project's SWMP. (Update the information below for each new SWMP
Administrator for Construction) (Copy of TECS Certification must also be included in the SWMP.)
C.EROSION CONTROL INSPECTOR: (As defined in Subsection 208) The Contractor may designate an Erosion Control Inspector.
The Erosion Control Inspector shall complete duties in accordance with subsection 208.03 (c) (Copy of TECS Certification must
also be included in the SWMP.)
4.STORMWATER MANAGEMENT CONTROLS FIRST CONSTRUCTION ACTIVITIES
THE CONTRACTOR SHALL PERFORM THE FOLLOWING:
A.POTENTIAL POLLUTANT SOURCES
Evaluate, identify locate and describe all potential sources of pollutants at the site in accordance with subsection 107.25
CDPS-SCP and place in the SWMP notebook. All control measures related to potential pollutants shall be shown on the
SWMP site map by the Contractor's SWMP Administrator for Construction.
B.OFFSITE DRAINAGE (RUN ON WATER)
Describe and record control measures on the SWMP Site Map that have been implemented to address off site run-on
water in accordance with subsection 208.03.
C.VEHICLE TRACKING PAD/VEHICLE TRACKING CONTROL
Control measures shall be implemented in accordance with subsection 208.04.
Name/Title Contact Information
Angie Fowler, P.E. / Water Quality Engineer 970-945-1004 / angief@sgm-inc.com
Name/Title Contact Information (phone & email)Certification #Start Date Engineer Approval
01-27-21
118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
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Structure
Numbers
CDOT ACCESS PERMIT #320024
SWMP (2)
SWMP 2 of 5
Project No./Code
22
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Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-SWMP
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 12/7/2020
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
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D.PERIMETER CONTROL
1. Perimeter control shall be established as the first item on the SWMP to prevent the potential for pollutants leaving the
construction site boundaries, entering the stormwater drainage system, or discharging to state waters. Perimeter control
shall be in accordance with subsection 208.04.
2. Perimeter control may consist of berms, silt fence, erosion logs, existing landforms, or other control measures as
approved.
5.DURING CONSTRUCTION
RESPONSIBILITIES OF THE SWMP Administrator for Construction
The SWMP is a "living document" that is continuously reviewed and modified throughout the construction phasing. During construction,
the following items shall be added, updated, or amended as needed by the SWMP Administrator for Construction in accordance with
subsection 208.03.
During construction, indicate how items that have not been addressed during design are being handled in construction. If items are
covered in the template or other sections of the SWMP, indicate below what section the discussion takes place.
A.STOCKPILE MANAGEMENT: Shall be done in accordance with subsection 107.25 and 208.07.
B.CONCRETE WASHOUT: Concrete wash out water or waste from field laboratories and paving equipment shall be contained in
accordance with subsection 208.05.
C.SAW CUTTING: shall be done in accordance with subsection 107.25, 208.04, 208.05.
D.STREET SWEEPING: shall be done in accordance with subsection 208.04.
6. INSPECTIONS
A. Inspections shall be in accordance with subsection 208.03 (c).
7. CONTROL MEASURE MAINTENANCE
A. Maintenance shall be in accordance with subsection 208.04 (f).
8. RECORD KEEPING
A. Records shall be kept in accordance with subsection 208.03 (d).
9. INTERIM, PERMANENT STABILIZATION and LONG TERM STORMWATER MANAGEMENT
The Contractor shall comply with all interim stabilization and permanent stabilization requirements in accordance with subsection
208.04(e).
A.SEEDING PLAN
Seeding will be required for an estimated 0.94 acres of disturbed area within the project limits which are not surfaced. The
following seeding mixture is based on Garfield County Specifications. The Contractor shall verify with the County that this seeding
mix is appropriate for project. The following types and rates shall be used:
B.SEEDING APPLICATION: Drill seed 0.25 inch to 0.5 inch into the soil. In small areas not accessible to a drill, hand broadcast or
hydroseed at double the rate and rake 0.25 inch to 0.5 inch into the soil per subsection 212. Soil compaction shall be
minimized for areas where permanent stabilization will be achieved through vegetative cover.
C.MULCHING APPLICATION: Apply a minimum of 2 tons of certified weed free native hay or 2 1/2 tons of certified weed free
straw per acre and in accordance with Section 213, and mechanically crimp it into the soil in combination with an organic
mulch tackifier.
1. Prior to winter shutdown or the summer seeding window closure: Uncompleted slopes shall be mulched with 2 tons of
mulching (weed free) per acre, mechanically crimped into the topsoil in combination with an organic mulch tackifier per
subsections 208 and 213.
D.SPECIAL REQUIREMENTS:
1. Due to high failure rates, hydroseeding will not be allowed for permanent stabilization.
E.SOIL CONDITIONING AND FERTILIZER REQUIREMENTS: Minimum requirements for all disturbances to receive seeding (native).
*Biological nutrient shall not exceed 8-8-8 (N-P-K).
Humate shall be in accordance to 212.02. Humate and compost shall also be approved by Garfield County.
F.SOIL RETENTION COVERING: On slopes and ditches requiring a blanket or turf reinforcement mat (trm), the blanket/trm shall be
placed in lieu of mulch and mulch tackifier and placed after seeding (native). See Erosion Control Plan for blanket/trm
locations.
G.RESEEDING OPERATIONS/CORRECTIVE STABILIZATION
Prior to partial acceptance.
1. Seeded areas shall be reviewed during the 7 day inspections by the SWMP Administrator for Construction and or
Erosion Control Inspector for bare soils caused by surface or wind erosion. Bare areas caused by surface or gully erosion,
blown away mulch, etc. shall be re-graded, seeded, and have the designated mulching applied as necessary, at no
additional cost to the project.
2. The Contractor shall maintain seeding/mulch/tackifier/blanket/TRM, mow to control weeds or apply herbicide to
control weeds in the seeded areas until Partial Acceptance of the stormwater construction work.
10. PRIOR TO PROJECT FINAL ACCEPTANCE
A. Partial Acceptance shall be in accordance with subsection 107.25 (d), 208.10 and 214.04. At the Partial Acceptance of the
project, it shall be determined by the SWMP Administrator for Construction and the Engineer which temporary control
measures shall remain until 70% revegetation is established or which shall be removed.
B. At the end of the project, all ditch checks shall either consist of temporary erosion logs (or equivalent) or permanent rip-rap.
C. All storm drains shall be cleaned prior to the Final Acceptance of the project. Work shall be included in 202 Clean Culvert.
11. NARRATIVES
Control Measure Matrixes During Construction:
1.Control measure narratives have been included for the CDOT Standard Specifications and Standard Plan M-208 and M-216
along with any non-standard control measures approved during the design process. If a Non-Standard Control Measure not
included in the SWMP is proposed and approved by the Engineer the SWMP Administrator for Construction shall do the
following: Place an “X” in the column for non-standard and complete a Non-Standard Control Measure Specification and
Narrative covering the what, when, where and why the control measure is being used shall be add to the SWMP. The
appropriate “X” shall also be added to the implementation phase(s).
2. The SWMP Administrator for Construction shall place an “X” in the column In Use On Site when the control measure has
been installed.
3. A “P” in the Initial Activities Column indicates that the control measure shall be installed before construction activity
starts. Locations and quantities will be discussed during the Environmental Pre-construction Conference with the Regional
Water Pollution Control Manager.
Soil conditioner paid for as Item 212-Soil Conditioning (Acre)
Biological
nutrient organic
based fertilizer
(lbs/acre)*
Humate
(lbs/acre)
Compost (cys/acre)
All areas <2:1
(1/2 inch depth)
Spray on Amendment
(lbs/acre)
>2:1 slopes only
300 200 65 3500
COMMON NAME BOTANICAL NAME LBS. PLS PER ACRE
Bluebunch Wheatgrass
Western Wheatgrass Pascopyrum Smithii
Basin Wildrye Leymus Cinereus
Mountain Sage Artemesia Tridentata
Sandberg's Bluegrass Poa Secunda
Side-Oats Grama Boutelous Curtipendula
Needle and Thread Stipa Comata
Blue Grama Bouteloua Gracilis
Galleta Hilaria Jamesii
TOTAL
01-27-21
118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
SWMP (3)
SWMP 3 of 5
Project No./Code
23
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--
Sheet Number
No Revisions:
Revised:
Void:
As Constructed
Drawing File Name: RiflePit-Rdwy-SWMP
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 12/7/2020
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
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Quality Control:Subset Sheets:
APPLICATION,
CONTROL MEASURE NARRATIVE
M-
STANDARD or
"X" for NON-
STANDARD
IN
USE
ON
SITE
CONTROL MEASURE IMPLEMENTATION PHASE
INITIAL
ACTIVITIES
INTERIM
ACTIVITIES
PERMANENT
STABILIZATION
PROTECTION OF EXISTING WETLANDS
Fence (plastic) and erosion logs
Fence (plastic) shall be placed in combination with erosion logs to prevent encroachment of construction traffic and sediment
into state waters prior to start of construction disturbances. Fence (plastic) shall be placed adjacent to the wetlands; erosion logs
shall be placed between the plastic fence and disturbance area. Logs shall be placed to direct flows away from or filter water
running into wetlands from disturbance areas.
PROTECTION OF EXISTING TREES/LANDSCAPING
Fence (plastic)
Fence (plastic) shall be used in areas indicated in the plans to prevent encroachment of construction traffic and sediment for the
protection of mature trees and/or existing landscaping prior to start of construction disturbances.
CHECK DAM/DITCH CHECK
Erosion log, silt berm, silt dike, rock check dam
Placed in ditches immediately upon completion of ditch grading to reduce velocity of runoff in ditch. For existing ditches, place
prior to start of construction disturbances.
M-208
Storm Drain Inlet Protection In Paved Roadways (Type 1,
2 and 3 as shown on M-208-1, sheet 5 of 11)
Manufactured storm drain inlet protection placed prior to construction disturbances as detailed in M-208-1, to protect existing
inlets or immediately upon completion of new inlets to prevent sediment from entering the inlet throughout construction.
M-208
Storm Drain Inlet Protection In Native Seed Areas (M-604
Standard Inlets Type C and D)
Erosion logs or aggregate bags placed around inlet grate to prevent sediment from entering inlet. Place prior to construction
disturbances to protect existing inlets or immediately upon completion of new inlets.
M-208
CULVERT INLET/OUTLET PROTECTION
Erosion logs, aggregate bags
Placed at mouth of culvert inlets and over top of culvert at inlet and outlet where disturbance may be occurring adjacent to pipe
to prevent sediment laden water from entering pipe or drainage. Place prior to start of construction disturbances.
M-208
TYPE C, TYPE D AND TYPE 13 PROTECTION
Erosion logs, aggregate bags, erosion bales
Placed around inlet grate or slope and ditch paving to prevent sediment from entering inlet. Place prior to start of construction
disturbances.
M-208
STOCKPILE PROTECTION
Temporary berm, erosion logs, aggregate bags*
Placed within specified distance, in accordance with subsection 208.06, from toe to contain sediment around stockpile.
*Aggregate bags are easily moved and replaced for access during the work day. Place prior to start of stockpile, increase control
as stockpile increases size.
M-208
TOE OF FILL PROTECTION
Erosion logs, temporary berm, silt fence, topsoil windrow*
Place prior to slope/embankment work to capture sediment and protect and delineate undisturbed areas. *Can be used to
stockpile topsoil for salvage.
M-208
PERIMETER CONTROL
Erosion logs, silt fence, temporary berm, topsoil windrow*
Placed prior to construction commencing to address potential run-on water from off site, and to divert around disturbed area.
*Can be used to stockpile topsoil for salvage.
M-208 X X
SEDIMENT CONTROL/SLOPE CONTROL
Silt fence, erosion logs
Placed on the contour of a slope to contain and slow down construction runoff. Place prior to start of construction disturbances.M-208 X X
TEMPORARY SEDIMENT TRAP
Used to capture sediment laden runoff from disturbed areas < 5 acres during construction. Place prior to start of construction
disturbances. Outlets that withdraw water from or near the surface may be installed when discharging from basins and
impoundments.
M-208
EMBANKMENT PROTECTION OR TEMPORARY SLOPE DRAIN Placed as a conduit or chute to drain runoff down slope and to prevent erosion of slope.M-208
OUTLET PROTECTION
Riprap, or approved other
Material placed as energy dissipator to prevent erosion at outlet structure.M-601-12
CONCRETE WASHOUT
In-ground or fabricated
Construction control, used for waste management of concrete and concrete equipment cleaning. Place prior to start of concrete
activities.
M-208 X X
VEHICLE TRACKING PAD Source control, placed to prevent tracking of sediment from disturbed area to offsite surface. Place prior to start of construction
disturbances.
M-208 X X
Engineered SEDIMENT BASIN
Constructed early in project, prior to storm sewer/ditches and in accordance with 208.05(p) to capture storm flow. Outlet
structure and/or outfall shall be modified for temporary sediment control using an approved non-standard detail. Outlets that
withdraw water from or near the surface shall be installed when discharging from basins and impoundments, unless infeasible
DEWATERING
(Contractor is responsible for obtaining a permit from
Colorado Department of Health and Environment.)
Shall be done in such a manner to prevent potential pollutants from entering state waters.TBD
TEMPORARY STREAM CROSSING Constructed over stream or drainage to prevent discharge of pollutants from construction equipment into water.
CLEAN WATER DIVERSION Placed to divert clean surface or ground water around disturbance area to prevent it from mixing with construction runoff.
OTHER
STRUCTURAL Control Measures that may be potentially used on the project for erosion and sediment control; practices may include, but are not limited to:
01-27-21
118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
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JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
SWMP (4)
SWMP 4 of 5
Project No./Code
24
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--
Sheet Number
No Revisions:
Revised:
Void:
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Drawing File Name: RiflePit-Rdwy-SWMP
Date Comments Init.Rev.
Sheet RevisionsComputer File Information
Print Date: 1/26/21
Last Modification Date: 12/7/2020
RN
Autocad Ver. 2020
SGM Project No.: 2019-341.002
Scale: As Shown
Quality Control:Subset Sheets:
APPLICATION,
BMP/CONTROL MEASURE NARRATIVE
M-
STANDARD or
"X" for
NON-
STANDARD
IN
USE
ON
SITE
BMP/CONTROL MEASURE PHASING
INITIAL
ACTIVITIES
INTERIM
ACTIVITIES
PERMANENT
STABILIZATION
* VEGETATIVE BUFFER STRIP
Fence (plastic)
Finishing component for filtering sediment-laden runoff from disturbance area. Area within CDOT ROW or temporary easement to
be identified on SWMP prior to construction starting.
GRADING APPLICATIONS (LANDFORM)
Existing or created landforms may be used as a control measure if they prevent sediment from entering or leaving the disturbance
area. If a landform directs flow of water to a concentrated outfall point, the outfall point shall be protected to prevent erosion.
Area to be identified on SWMP prior to construction starting.
M-208
TOPSOIL MANAGEMENT STOCKPILE/SALVAGE
Windrow or stockpile
Prior to embankment work commencing, existing topsoil shall be scraped to a depth of 4 inches or as specified, and placed in
stockpiles or windrows. Upon completion of final grading, topsoil shall be evenly distributed over embankment to a depth of 4
inches or as specified.
M-208 X X X
SURFACE ROUGHENING / GRADING TECHNIQUES Temporary stabilization of disturbance and to minimize wind and erosion.
SEEDING (TEMPORARY)Temporary stabilization used for over wintering of disturbance or used to control erosion for areas scheduled for future
construction.
BONDED FIBER MATRIX or MULCHING (HYDRAULIC)
Not to be used in areas of concentrated flows, i.e. ditch lines. To be for either Interim or Permanent Stabilization placed as a
surface cover for erosion control. May be used as surface cover when work is temporarily halted and as approved by the
Engineer for stockpiles.X
Straw or Hay MULCH/MULCH TACKIFIER Interim or Permanent Stabilization placed as a surface cover for erosion control and or seeding establishment. To be installed as
Interim Stabilization as a surface cover when work is temporarily halted and as approved by the Engineer X
SPRAY-ON MULCH BLANKET (Not to be used in areas of
concentrated flows, i.e. ditch lines.)
Interim or Final Stabilization placed as a surface cover for erosion control and or seeding establishment. To be installed as
temporary surface cover when work is temporarily halted and as approved by the Engineer
SEEDING PERMANENT (NATIVE)Final Stabilization of disturbance and to reduce runoff and control erosion on disturbed areas.X
SOIL RETENTION BLANKET (SRB)Final Stabilization of disturbance and to reduce runoff and control erosion on disturbed areas.M-216
TURF REINFORCEMENT MAT (TRM)Final Stabilization of disturbance and to reduce runoff and control erosion on disturbed areas. Placed in channels or on slopes for
erosion control, channel liner and seeding establishment.
M-216
Sweeping Source control, used to remove sediment tracked onto paved surfaces and to prevent sediment from entering drainage system.
Sweep daily and at the end of the construction shift as needed. Kick brooms shall not be permitted.
OTHER
NON-STRUCTURAL Control Measures that may be potentially used on the project for erosion and sediment control; practices may include, but are not limited to:
Erosion control devices are used to limit the amount of soil loss on site. Sediment control devices are designed to capture sediment on the project site. Construction controls are control measures related to construction access and staging.
Control Measure locations are indicated on the SWMP Site Map
* Use of vegetative buffer strip requirements. The CDPHE Water Quality Control Division Technical Memorandum dated August 27, 2015 clarifies the requirements for utilization of existing vegetation as a buffer type of sediment control
measure, while maintaining compliance with the CDPS permit for Stormwater Discharges Associated with Construction Activity - CDPS Permit No. COR4000000. In general, the division does not recommend that vegetated buffers be
implemented as a sediment removal control measure for runoff from disturbed areas at construction sites, unless implemented as a “finishing” component of a treatment train comprised of additional, adequate up-gradient Control
Measures. The entire memorandum can be found at: https://www.colorado.gov/pacific/sites/default/files/Vegetative%20Buffer%20Memo.pdf
01-27-21
118 West Sixth Street, Suite 200Glenwood Springs, CO 81601970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
SWMP (5)
SWMP 5 of 5
Project No./Code
25
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Last Modification Date: 12/7/2020
RN
Autocad Ver. 2020
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Quality Control:Subset Sheets:
12.TABULATION OF STORMWATER QUANTITIES
A. BMP sediment removal and disposal but shall be paid for as: 208 Removal and Disposal of Sediment (Equipment) and 2018
Removal and Disposal of Sediment (Labor). All other BMP maintenance shall be included in the cost of the BMP Device.
B. It is estimated that 5 hours combination loader (80-125 horsepower) may be required for miscellaneous erosion control work as
directed by the Engineer. Work shall be paid for as: 203 Combination Loader.
C. Establishment of seeded areas will not be paid for separately, but shall be included in the work. This shall include weed control,
reseeding/mulch/tackifier.
*It is anticipated that additional control measures and control measure quantities not shown on the SWMP Site Maps shall be required
on the project for unforeseen conditions and replacement of items that are beyond their useful service life, see subsection 208.03 and
208.04. Quantities for all control measures shown above are estimated, and have been increased for unforeseen conditions and
normal control measure life expectancy. Quantities shall be adjusted according to the conditions encountered in the field as directed
and approved by the Engineer. Payment shall be for the actual work completed and material used.
**Pay Item 208-00071 is included for anticipated maintenance of vehicle tracking pads based on the service life of the control
measure in the field. The use of the material shall be directed and approved by the Engineer.
*** F/A refers to CDOT's Force Account Pay Items.
13. BIOLOGIC IMPACTS and DEWATERING
A.ENVIRONMENTAL IMPACTS:
1. Wetland Impacts: NO
2. Stream Impacts: NO
3. Threatened and Endangered Species: None
B.DEWATERING (Not Covered Under the CDPHE Low Risk Guidance Document of Uncontaminated Groundwater to Land):
1. Dewatering: Refer to other environmental permits in accordance with subsection 107.02 and the permits contained in Tab 16 of
the SWMP.
14. NOTES
A. Tracked vehicles will not be allowed onto the paved portion of CR 346 or paved roads. Tires of vehicles that will use the the
paved portion of CR346 shall be cleaned before traveling on asphalt surfaces. Sweeping shall be performed to maintain clean
paved surfaces.
Pay Item Description Pay
Unit
Initial
Const.
Interim
Const.
Permanent
Stabilization
*Total
Quantity
203-01594 Combination Loader Hour 5 5
207-00205 Topsoil CY 500 500
207-00210 Stockpile Topsoil CY 500 500
208-00002 Erosion Log Type 1 (12 inch)LF 6824 6824
208-00045 Concrete Washout Structure Each 2 2
208-00207 Erosion Control Management (ECM)Day 45 60
212-00006 Seeding (Native)Acre 0.94 0.94
212-00032 Soil Conditioning Acre 0.94 0.94
213-00003 Mulching (Weed Free)Acre 0.94 0.94
213-00061 Mulch Tackifier LB 188 188
01-27-21
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In Feet: 1" = 50'
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118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
EROSION CONTROL (1)
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RN
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01-27-21
Graphic Scale
In Feet: 1" = 50'
0 25 50 100
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
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JJL
JJL
Structure
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CDOT ACCESS PERMIT #320024
EROSION CONTROL (2)
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Autocad Ver. 2020
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01-27-21
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In Feet: 1" = 50'
0 25 50 100
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
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JJL
JJL
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CDOT ACCESS PERMIT #320024
EROSION CONTROL (3)
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01-27-21
RiflePit-Signing 118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
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SIGNING & STRIPING
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Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
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Drawn By:
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JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
CROSS SECTIONS (1)
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RN
Autocad Ver. 2020
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Quality Control:Subset Sheets:
01-27-21
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
Structure
Numbers
CDOT ACCESS PERMIT #320024
CROSS SECTIONS (2)
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Project No./Code
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RN
Autocad Ver. 2020
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01-27-21
RiflePit-DwayAT 118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Engineer:
Drawn By:
Sheet Subset:
JJL
JJL
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Numbers
26
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WB-50 TURNING MOVEMENT
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Revised Floodplain Development Permit Narrative for Rifle Pit #1 August 2022
E
Attachment E
Comprehensive Wetland Delineation Report & Boundary Confirmation Request to USACE
USACE Boundary Confirmation from Tyler Adams
SPK# 2020-00172
Prepared for:
U.S. Army Corps of Engineers
Colorado West Regulatory Office IHC Scott
Albuquerque District, Regulatory Division 9200 East Mineral Ave, Suite 400
400 Rood Avenue, Room 224 Centennial, CO 80112
Grand Junction, Colorado 81501-2563
Prepared by:
SGM, Inc.
259 Grand Avenue, Suite 200
Grand Junction, CO 81501
2019-341.002
February 28, 2022
www.sgm-inc.com
Comprehensive Wetland Delineation Report &
Request for Boundary Confirmation
Rifle Gravel Pit #1
Garfield County, Colorado
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
i
Comprehensive Wetland Delineation Report &
Request for Boundary Confirmation
Rifle Gravel Pit #1
(SPK# 2020-00172)
Garfield County, Colorado
Prepared for:
U.S. Army Corps of Engineers
Colorado West Regulatory Office IHC Scott
Albuquerque District, Regulatory Division 9200 East Mineral Ave, Suite 400
400 Rood Avenue, Room 224 Centennial, CO 80112
Grand Junction, Colorado 81501-2563
Prepared by:
SGM, Inc.
259 Grand Avenue, Suite 200
Grand Junction, CO 81501
Submitted to:
Colorado West Regulatory Office
U.S. Army Corps of Engineers
400 Rood Avenue, Room 224
Grand Junction, Colorado 81501-2563
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
ii
Contents
1. APPLICANT AND SITE INFORMATION ........................................................................................................... 1
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
1
1. APPLICANT AND SITE INFORMATION
IHC Scott (formerly Scott Contracting Inc.) requested that SGM delineate all potential wetlands and
other Waters of the U.S. for a gravel pit development project in Garfield County, Colorado. The
project would be new development, located on the site of an existing cattle pasture which has been
irrigated up until 2021. The parcel is divided by an irrigation tailwater ditch that carries agricultural
return flows to a discharge point on the Colorado River. IHC Scott is proposing partial development
of the parcel, with the intention of confining the pit infrastructure to upland portions of the property
and entirely avoiding direct impacts to jurisdictional wetlands and Waters of the U.S. (WoUS) on the
property. There are anticipated to be no regulated impacts as a result of the proposed activity. The
conceptual outline of the proposed development is discussed in this report, but is not addressed in
depth report.
This report has been prepared in accordance with regulatory guidance for submittal to the U.S. Army
Corps of Engineers (USACE) to request a wetland boundary confirmation without accompanying
jurisdictional determination. A No Permit Required letter is not requested at this time. This report
has been submitted to assist in planning and communication between IHC Scott and regulatory
agencies, primarily the USACE, but also Garfield County.
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
2
· The findings of the August 13, 2021 ARDR were rejected, and a resubmittal was requested
that would use the transect-based approach and incorporate Problematic Hydric Soils
procedure into the boundary determinations.
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
3
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
4
2. PROJECT DESCRIPTION
IHC Scott is proposing to construct a new gravel pit development project in Garfield County,
Colorado. The project would be new development, located on the site of a cattle pasture receiving
irrigation return flows; the pastures are not intentionally irrigated at this time but have been in the
recent past (Figures 1 and 2). The applicant is proposing partial development of the parcel, with the
intention of confining the pit infrastructure only to upland portions of the property (generally the
eastern portion), and entirely avoiding direct impacts to jurisdictional wetlands and WoUS
(generally on the western portion of the property).
The subsurface conditions are typical of gravel pits and aggregate mines in the Colorado River
floodplain: the surface layer consists of between one and seven feet of alluvially-deposited fine
sediments (primarily silts and clays), overlying 17-22 feet of alluvial gravels. Shallow groundwater,
connected to the water table of the Colorado River, saturates the gravels and is generally present
throughout the project site at a depth of between one and five feet. These assessments are based
on exploratory subsurface drilling work from 2008 (Appendix E).
The proposed development would be a wet mining operation. In wet mining operations of the type
IHC Scott proposes, the overburden is removed and stockpiled for onsite use or sale as topsoil, and
the saturated alluvial gravels are excavated in their saturated state using a long-reach excavator.
No dewatering activity or groundwater pumping occurs, and the excavated pit fills with
groundwater to become a pond as mining progresses through the site. This is in contrast to a typical
aggregate mine operation, where dewatering (generally through pumping) lowers the groundwater
and then the pit is excavated with machinery in the bottom of the pit, and after operations are
complete the dewatering stops and the pit is allowed to fill with groundwater to become a pond.
A very brief conceptual description of the proposed mining plan is included here for reference. Note
that permit applications with the Division of Reclamation, Mining, and Safety (DRMS) and Garfield
County Community Development are both in process and specific operational details of this project
may be subject to change based on feedback from these agencies.
· A paved access apron would be constructed to access the project site from the Interstate-
70 frontage road. CDOT has reviewed the plans and issued an access permit to allow for this
construction.
· A processing and sales facility (scale house) would be constructed at the entrance to the
project site. This would include the material stockpiles, loading chute and processor, the
scale house, vehicle parking, and the minimal facilities needed onsite staff (portable toilets,
water tank, work trailer).
· The overburden (1-7 ft of fine sediments) would be removed from the mine area. The
overburden would be used to construct a 5-ft tall perimeter berm around the mine area, to
control visual and noise impacts in accordance with Garfield County Land Use Code (LUC)
standards. The outer edge of the perimeter berm would be located 25 feet from the
boundary of any wetland areas, pending approval of a variance from the 35-foot wetland
setback in the LUC. The berm surface would be stabilized and re-seeded to control erosion.
Any remaining overburden material would be stockpiled at the processing facility for sale as
topsoil.
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
5
· The working surface of the mine would consist of the exposed alluvial gravel surface. A long-
reach excavator stationed on the edge of the pit would excavate material to a depth of
approximately 20 feet. The pit would be full of water, forming a pond that expands as the
excavator continues to remove material, and which is in direct contact with the water table
of the Colorado River via lateral migration through the underlying permeable gravels.
Excavated material would be piled on the edge of the pond for approximately 24 hours, to
allow drainage of free water from the material and back into the pond.
· Sideload dump trucks would travel to the pond edge, and would be loaded with the dried
material on a daily basis. The dump trucks would transport the dried material from the active
excavation area to the processing facility, where the material would be stockpiled for
washing, processing, and subsequent sale.
· Any agricultural return flows in the tailwater ditch, which are estimated at less than 2 cfs
during peak irrigation season, would be discharged into the pond. The discharge would mix
with the alluvial aquifer waters which are exposed in the pond, and the combined waters
would migrate laterally through the underlying permeable gravels into the larger Colorado
River water table. Given the minimal flows in the ditch, the large size of the pond (estimated
at 6 acres within the first year of operation), and the highly-permeable nature of the gravel,
the agricultural return flows would have a negligible effect on water levels in the pond. As
excavation proceeds, the eastern portions of the tailwater ditch, which is artificially
excavated in an upland area, would be subsumed into the expanding pond boundaries, until
under final conditions the discharge point would be where the ditch enters the eastern
boundary of the property.
· Reclamation would proceed in concert with the excavation. A six-foot wide fringe of gentle
slopes (e.g., 5:1 slopes) would be left at the inner edge of the perimeter berm, and planted
with wetland reclamation species. The intention is for the six-foot wide fringe to be nearly
inundated during high-water periods as the water table rises, and then to be progressively
exposed as the water table drops during the course of the growing season. Note that this
draft reclamation effort is in compliance with Garfield County LUC standards, and is not
intended to serve as formal wetland mitigation per USACE standards.
· At this time, the proposed mine would operate daily, with excavation and processing
occurring eight months of the year (roughly April – May) and with material sales occurring
year-round. Total recoverable volume is estimated at approximately 300,000 cubic yards of
aggregate, which is expected to support operations for between three and five years. Details
of the proposed operation have been provided to both Garfield County and the Colorado
Division of Reclamation, Mining, and Safety (DRMS). The final planning for the project is still
being developed with a land use development permit currently in review with Garfield
County and a mining plan in review with DRMS. However, under no foreseeable
circumstances would the operating area of the mine be extended into areas that have been
mapped as wetlands.
To determine regulatory authority over the proposed project, a delineation of wetlands and Waters
of the US was conducted in accordance with the USACE 1987 Wetland Delineation Manual and the
Arid West regional supplement. The site assessment included the entire parcel, although the focus
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
6
and the Comprehensive Delineation was on the portion of the site where development could
potentially occur, and did not extend to the small “panhandle” on the northeast corner of the
property.
There are a total of 1.13 acres of non-wetland open water within the parcel (all associated with the
artificially-excavated tailwater ditch), and a total of 18.28 acres of wetlands were delineated within
the parcel. Irrigation waters from the ditch clearly provide some portion of the hydrology supporting
the wetland complex. However, shallow groundwater associated with the Colorado River floodplain
and water table are also assumed to be partially supporting wetland conditions. No attempt has
been made to conclusively determine the extent of agricultural water support of the wetlands on
the parcel, and no discussion of jurisdictional status is included in this report. This request is solely
for a Boundary Confirmation of the mapped wetland areas, irrespective of potential jurisdictional
status, and IHC Scott intends to avoid direct impacts to all wetlands regardless of jurisdictional
status.
Note that IHC Scott’s proposed development plan does involve impacts to the tailwater ditch (see
Appendix A). These impacts would qualify as exempt activities under the Clean Water Act (CWA)
Section 404(f)(1)(C) exemptions for the construction and maintenance of jurisdictional ditches. This
contention is based on the following points:
· The tailwater ditch is a “constructed or excavated channel used to convey water,” in this
case one that conveys irrigation waters from their place of use to a discharge point into
natural waters (the Colorado River). It therefore qualifies as an irrigation ditch under 85 FR
22250.
· The purpose of IHC Scott’s diversion of the ditch waters into their excavated pond is to
ensure the continued function of the ditch, which is the discharge of irrigation return flows
to receiving waters. There are no downstream users or water right holders on the ditch; IHC
Scott’s obligation as owner of the ditch is to ensure that the irrigation return flows reach the
Colorado River.
· IHC Scott’s revision of the ditch design would not include any areas of the ditch that currently
host abutting or adjacent wetlands. This is in recognition of the fact that the wetlands may
also be supported by natural hydrology. IHC Scott intends to alter only that portion of the
ditch that is clearly an artificial channel excavated in uplands with no adjacent wetlands (see
Appendix A). No direct impacts to any wetlands would occur as a result of the ditch work.
· Part 1 of the recapture provision (CWA Section 404(f)(2)) would not apply to this work
because there is no intention to convert any area of WoUS to a use to which it was not
previously subject. There are no impacts to wetlands, no conversions of wetlands to new
uses, and no degree of piping the ditch. In fact, the express purpose of the ditch alterations
is to avoid impacts to the wetlands while continuing to fulfill the requirement to discharge
the irrigation return flows.
· In addition, Part 2 of the recapture provision (CWA Section 404(f)(2)) would not apply to this
work because there would be no impairment to the flow or circulation of WoUS. The natural
hydrology supporting the wetlands on the western portion of the property would not be
altered, since the proposed mine would not alter the current conditions under which shallow
groundwater passes under the site, through permeable gravels, and proceeds to
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
7
downstream waters. In addition, the existing agricultural waters that may be partially
supporting the wetlands would continue to be available, given their discharge into the pond
and incorporation into the shallow groundwater on the site.
This discussion tiers to and relies upon the definitions and procedures jointly laid out by the USACE
and the U.S. Environmental Protection Agency concerning the applicability of ditch exemptions (EPA
2020).
This report has been prepared in accordance with regulatory guidance for submittal to the USACE
to request a wetland boundary confirmation. No nationwide permit is requested at this time. This
report has been submitted to assist in planning and communication between IHC Scott and the
regulatory agencies, primarily the USACE, but also Garfield County.
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
8
3. PROJECT AREA DESCRIPTION
The primary vegetation type across the Project area is historically irrigated pasturelands. Historic
aerial photography shows the parcel had been flood irrigated for many years. With changes in
utilization of the agricultural land, the extent and amount of irrigation has expanded and contracted
over the past several decades. There are irrigation ditches and irrigation flows on the parcel that at
one time were directed toward supporting pasture vegetation, and they have not been consistently
used in the last two seasons since IHC Scott acquired the property. There are also discharges from
the irrigation tailwater ditch which terminates on the property, where it discharges agricultural
water to flow in a naturalized channel to an eventual confluence with the Colorado River. These
surface inputs are contributing to the extent of wetlands on the property. However, the surface of
the parcel is also elevationally very close to the Colorado River, and it is assumed that elevated
ground waters are contributing to the support of wetlands as well.
The pasturelands are dominated by agricultural graminoids and ruderal weeds. There is minimal
evidence of recent seeding or other direct management, and some representative dominant species
include common timothy (Phleum pratense – FACU), inland saltgrass (Distichlis spicata – FAC), alkali
sacaton (Sporobolus airoides – FAC), white goosefoot (Chenopodium album - FACU), and chicory
(Cichorium intybus – FACU). Russian olive (Elaeagnus angustifolia – FAC) is a dominant component
in portions of the parcel, generally in transition areas between pastures and wetlands.
The wetland communities grade generally from east to west, from occasionally saturated areas
dominated by arctic rush (Juncus balticus – FACW), timothy, and saltgrass, through seasonally
saturated wetland meadows dominated by sedges (Carex spp.) and arrowgrass (Triglochin maritima
– OBL), and into perennially flooded marshes dominated by obligate emergent species such as
bulrush (Schoenoplectus spp.) and cattail (Typha latifolia).
Using data from the nearest weather station (Rifle), recorded temperatures for the reporting period
(1910 to 2009) range from an average low of 9 degree Fahrenheit (˚F) in January to an average high
of 90˚F in July. Average annual precipitation of 11.6 inches consists primarily of winter snows, and
summertime rain precipitation events (Western Regional Climate Center [WRCC] 2021).
Typical conditions in the upland part of the property. Bulrush and Juncus wetlands on the property.
Wetland Delineation Report
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9
Wetland Delineation Report Rifle Gravel Pit #1 February 2022 10 Figure 1: Vicinity Map
Wetland Delineation Report Rifle Gravel Pit #1 February 2022 11 Figure 2: Topographic Map
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4. WETLAND & WATERS DELINEATION
IHC Scott contracted with SGM for the delineation of all potential wetlands and WoUS on the parcel
to assist with project planning and development. As summarized in Section 1 and described in more
detail below, a comprehensive delineation has been performed at the request of the USACE,
incorporating 18 transects spaced at 100-ft intervals, resulting in collection of 188 WDDF data
points.
All delineations and assessments were completed by SGM’s Senior Ecologist Alex Nees, a certified
wetland delineator, with the assistance of SGM’s Eric Petterson, also a certified wetland delineator
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Rifle Gravel Pit #1 February 2022
13
NWI. Due to the subtle and variable conditions of surface water conditions, all wetlands were
categorized simply as PEM wetland type.
In addition to the PEM wetlands, one other WoUS type was delineated on the parcel:
· R3UBHx (Riverine, Upper Perennial, Unconsolidated Bottom, Permanently Flooded,
Excavated)
o This feature is the open water found in the tailwater ditch. The ditch was mapped
in NWI as PEM1F, but it appears that ongoing maintenance dredging has continually
removed emergent vegetation in the majority of the channel and preserved open-
water conditions.
See Figure 3: National Wetland Indicator Map, and Figure 6: Delineated Wetlands to compare
NWI mapping to the field delineation.
SSURGO Soil Review
SGM reviewed the Soil Survey Geographic Database (SSURGO, Figure 4) which indicated the
presence of four soil types within the parcel. The mapped soil unit boundaries were found to be
roughly accurate, although soil texture did vary widely, likely as a result of the combination of past
agricultural treatments and historic flood deposition/scouring events.
· Halaquepts, nearly level: This soil type dominates the western half of the property. It is a
saline soil type that experiences both a seasonal high water table and a period in which
evapotranspiration brings salts to the soil surface (USDA 2015). It is classed as moderately
to strongly saline, and is a hydric soil type. The halaquepts on the site are likely derived
from the local loams and sandy loams, but have been modified by the high water table and
evapotranspirative demand. The reported alkalinity of this soil is Moderately to Strongly
Alkaline, qualifying it as a problematic hydric soil per the Regional Supplement to the Corps
of Engineers Wetland Delineation Manual: Arid West (USACE 2010).
· Wann sandy loam, 1-3% slopes: This soil type surrounds the eastern portion of the
tailwater ditch on the property. It is a poorly-drained alluvial deposit that is non-saline to
slightly saline. It is similar to the halaquepts, but does not experience the seasonal high
water table and evapotranspiration necessary to concentrate salts at the soil surface. It is
a hydric soil type.
· Kim loam, 3-6% slopes: This soil type is limited to the northeast corner of the property. It
is also an alluvial deposit, but is well drained and does not have a high water table. Salinity
is negligible and it is not a hydric soil type.
· Olney loam, 1-3% slopes: This soil type is limited to the southeast corner of the property.
It is very similar to Kim loam, being an alluvial deposit that is well drained and does not
have a high water table. It may be very slightly saline. It is not a hydric soil type.
In summary, the soil review indicated that the project site is entirely dominated by loam deposits
overlying the alluvial gravels. The low-lying areas on the west end of the property are moderately
to strongly saline due to seasonal saturation/inundation and a strong evapotranspirative pump
that brings salts to the surface. Other portions of the site that do not experience
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Rifle Gravel Pit #1 February 2022
14
saturation/inundation are not notably saline. These mapping results were generally confirmed by
field investigations, and also correspond to the findings of some investigatory sub-surface drilling
logs (Appendix E).
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Rifle Gravel Pit #1 February 2022
15
b. The pH of the soil was measured at depths of 2-inches, 6-inches, and occasionally
12-inches if more conclusive results were needed. Measurements were taken using
a digital pH meter with a resolution of 0.1 pH and automatic temperature calibration
(Bluelab Soil pH Pen). The pen was calibrated using reference pH solutions on a
weekly basis during the delineation effort, and was stored in pH-neutral storage
solution when not in use. pH measurements are recorded on all WDDFs.
c. Data points where the soil returned a pH value of 7.9 or higher qualified as
“Moderately to Very Strongly Alkaline Soils” per the Arid West Manual. In these
settings hydric indicators may not form because the alkalinity reduces the ability of
iron and manganese to enter solution and form recognizable indicators. At these
data points, the “Other” indicator under Problematic Hydric Soils was marked, and
soils were not further evaluated, as they were assumed to be Hydric.
d. The procedure for Problematic Hydric Soils determination was followed (USACE
2010). Data points where soil pH was 7.9 or greater were considered to be wetlands
if hydrophytic vegetation and wetland hydrology indicators were present,
regardless of the observed presence of hydric soil indicators.
e. For data points with soil pH of less than 7.9, the standard wetland delineation
protocol was followed. The soil column excavated by the auger was evaluated for
the presence of hydric indicators. The plant species at the data point were recorded
and used to determine whether hydrophytic vegetation was present, and hydrology
was evaluated using direct observation of the auger hole, in combination with
evaluation of the primary and secondary hydrology indicators.
f. In summary, data points that indicated the presence of hydrophytic vegetation,
hydric soils OR a pH of 7.9 or greater, and wetland hydrology, were coded as
wetlands.
5. Based on the WDDF findings, the data points were coded as Wetland or Non-wetland in the
GIS. The delineation team then mapped the wetland boundaries displayed in Figure 6 in the
field using a sub-meter accuracy GPS, accounting for the data point findings and the totality
of observations from the site. This mapping is presented in Figure 6, and represents the
wetland boundaries for which SGM is seeking a Boundary Confirmation, based on
compliance with the Comprehensive Determination method as modified per the guidance
in the Arid West Regional Supplement.
Of note, alpha, alpha-dipyridyl dye was applied to saturated soils on a test basis, on numerous
occasions. In no case was the dye found to be a reliable indicator of the presence of reduced iron
in the soil, either in high-pH situations or in cases of obvious reducing conditions.
Wetland Delineation Report Rifle Gravel Pit #1 February 2022 16 Figure 3: National Wetlands Inventory
Wetland Delineation Report Rifle Gravel Pit #1 February 2022 17 Figure 4: SSURGO Soil Type
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
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Rifle Gravel Pit #1 February 2022
19
were delineated within the parcel, all of which are considered potentially jurisdictional and would
be avoided by IHC Scott’s development plan (Figure 6, and Appendix A). 1.13 acres of non-wetland
WoUS associated with the open water of the tailwater ditch were also delineated. The tailwater
ditch is artificially excavated and carries irrigation waters from their point of entry on the eastern
edge of the parcel towards the discharge point along the western edge of the parcel. However the
ditch is set within the floodplain of the Colorado River and has a discharge to the Colorado River.
Based on these factors the tailwater ditch has a nexus to a WoUS and Traditionally Navigable
Waterway (TNW), and is considered to be potentially jurisdictional. A wetland delineation map
(Figure 6) depicts the Investigation Area (i.e., the parcel boundaries), the wetland boundaries, and
the location of all aquatic resources noted during the survey. 188 WDDF points were established
during the survey to clarify and support the wetland boundary delineations, and the data forms
are included in Appendix B.
Tailwater Ditch (R3UBHx)
The tailwater ditch in this area supports and
abuts a wetland fringe as shown on Figure 6; the
wetland fringe generally occurs in the western
portions of the property. Where no abutting
wetlands are mapped, ongoing
dredging/maintenance activities, and steep
banks along the irrigation ditch have prevented
the establishment of wetland vegetation in the
ditch. The banks are clearly defined by the
artificial excavation line, transitioning directly
from open water to mesic pasture conditions.
Therefore, the ordinary high water mark
(OHWM) was delineated as the boundary for this non-wetland WoUS feature.
Emergent Wetlands (PEM)
Areas of emergent wetlands (PEM) within the Investigation Area are associated with irrigation
waters and with low-lying areas that may have natural subsurface hydrology (Figure 6).
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Rifle Gravel Pit #1 February 2022
20
Vegetation: The wetland communities grade
generally from east to west, from mesic and
occasionally saturated areas dominated by
arctic rush (Juncus balticus – FACW), common
timothy (Phleum pratense – FACU), and inland
saltgrass (Distichlis spicata – FAC), through
seasonally saturated wetland meadows
dominated by a number of sedges (Carex spp.)
and arrowgrass (Triglochin maritima – OBL).
Western portions of the parcel are perennially
flooded marshes dominated by obligate
emergents such as bulrush (Schoenoplectus
spp.) and cattail (Typha latifolia).
Soils: The soil conditions have been described in detail in Section 4.1.2 and Section 4.2. In general,
the soil pits associated with each data point generally corresponded to the SSURGO mapping. The
majority of the mapped wetland areas are within the halaquept zone or adjacent to it. However,
the soil pH was not consistently 7.9 or greater within the halaquept zone, and a large portion of
the data point determinations rested on typical hydric soil indicator presence. In general, soils pits
inside the wetland boundary showed evidence of anaerobic, redox conditions, most commonly
with a depleted soil matrix consistent with the Depleted Matrix indicator (Indicator F3). Soil pits
outside the wetland boundary generally lacked hydric soil indicators within the upper 12 inches of
soil, although redox traces were commonly observed at greater depths. The observed conditions
strongly suggest that the mapped wetlands on the property are saturated or have standing water
for a significant portion of the growing season. Soils outside the wetland boundaries have
seasonally shallow groundwater, but not for a sufficient period to generate redox conditions within
the upper 12 inches of the soil.
Hydrology: At the boundary of the wetland areas, hydrology indicators were generally secondary
indicators only, including visible saturation on imagery, dry-season water table, and a positive FAC-
Neutral Test. Hydrology was obvious in areas with soil saturation and standing water. During the
course of several visits to the site, surface water and saturation was observed to be relatively stable
and constant in extent (aside from where trespass irrigation waters discharged from the property
to the north were halted when the ditches were maintained). Some areas that were mapped as
wetlands displayed cracked soils and salt crusts consistent with depressional ponding and
Indicators B6 and B11.
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21
Table 1. Summary of Waters of the U.S. and Wetlands in Investigation Area
Name Jurisdiction Flow Frequency Receiving
Water Proximity Size (acres)
Last Chance Tailwater Ditch
WoUS – R3UBHx
Potentially
Jurisdictional Perennial Colorado
River Tributary 1.13
TOTAL NON-WETLAND WoUS 1.13
Wetland A
PEM
Potentially
Jurisdictional Semipermanent Colorado
River Adjacent 2.05
Wetland B
PEM
Potentially
Jurisdictional Seasonal Colorado
River Adjacent 0.14
Wetland C
PEM
Potentially
Jurisdictional Seasonal Colorado
River Adjacent 0.02
Wetland D
PEM
Potentially
Jurisdictional
Seasonal to
Semipermanent
Colorado
River Adjacent 6.00
Wetland E
PEM
Potentially
Jurisdictional Semipermanent Colorado
River Adjacent 9.86
Wetland F
PEM
Potentially
Jurisdictional Ephemeral Colorado
River Adjacent 0.21
TOTAL WETLANDS 18.28
Wetland Delineation Report Rifle Gravel Pit #1 February 2022 22 Figure 5: Comprehensive Delineation Study Design
Wetland Delineation Report Rifle Gravel Pit #1 February 2022 23 Figure 6: Delineated Aquatic Resources
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Rifle Gravel Pit #1 February 2022
24
5. FEDERALLY LISTED THREATENED OR ENDANGERED SPECIES
At this time, IHC Scott is only requesting a Boundary Confirmation, with the intention of completely
avoiding impacts to the wetlands on the property. Based on this avoidance directive from IHC Scott,
SGM has not identified any other federal nexus for the project at this time. A brief discussion of
federally listed species follows here, to inform the USACE and the planning process.
Seven federally listed species and one Candidate species were evaluated for their occurrence on
or adjacent to the parcel, per the USFWS Threatened and Endangered species list provided by the
IPaC database (USFWS 2022). Based on this analysis, the USFWS identified the Mexican spotted
owl (Strix occidentalis lucida), yellow-billed cuckoo (Coccyzus americanus), bonytail chub (Gila
elegans), Colorado pikeminnow (Ptychocheilus lucius), humpback chub (Gila cypha), razorback
sucker (Xyrauchen texanus), monarch butterfly (Danaus plexippus), and Ute Ladies’-tresses
(Spiranthes diluvialis) as potentially occurring in the area.
Mexican Spotted Owl – Threatened. This species occurs in closed canopy conifer forests and
deeply incised canyons in desert habitats. The project area is outside of the range of this species,
and there are no canyons or coniferous habitats in the project area. There is no likelihood that
Mexican spotted owls forage in the project area, given a lack of suitable habitat of any type. This
project would have no effect on the Mexican spotted owl or their habitats.
Yellow-billed Cuckoo - Threatened. This species occurs in dense riparian habitats with cottonwood
(Populus deltoides) overstories with dense understory shrubs near rivers. The project area occurs
at the edges of the general range of yellow-billed cuckoo but is located outside any mature riparian
woodland habitats. The site is dominated by Russian olive and pasture conditions, and is heavily
grazed with minimal shrub cover. No mature riparian woodland/shrubland habitat suitable for the
species occurs on the parcel. There are no known occupied habitats in the near vicinity and no
records of cuckoo occurring in the greater area; it is highly unlikely that cuckoos forage in the
project area, given a lack of suitable riparian habitats. This project would have no effect on the
cuckoo or their habitats.
Colorado River Endangered Fish - Endangered. The USFWS identified the bonytail chub, Colorado
pikeminnow, humpback chub and the razorback sucker as potentially occurring or being affected
from activities on the parcel. These species occur in lower elevation, larger rivers associated with
the Colorado River. The Colorado pikeminnow and razorback sucker have mapped Critical Habitat
extending up the Colorado River to the Highway 13 bridge in Rifle. Potential activities on the parcel
would not occur in the Colorado River and would not discharge sediments into the river; the parcel
is approximately five river miles upstream from designated Critical Habitat.
The project would result in minor water depletions as a result of increased evaporative losses from
the surface of the dredged pond as compared to current conditions. IHC Scott is required to
develop a Supplementary Water Supply Plan (SWSP), which would replace those losses with
releases to the Colorado River from other water rights held by IHC Scott. As a result of the SWSP,
there would be no indirect loss in in-stream flows as a result of the project. The project would also
be required to implement a stormwater management plan, in compliance with DRMS regulations
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Rifle Gravel Pit #1 February 2022
25
as well as for Garfield County LUC standards. This would mitigate the risk of significant
sedimentation impacts to these fish.
Due to the requirement to provide supplementary water to offset evaporative losses, as well as
implementation of stormwater controls, it is not anticipated that the project would result in any
measurable or meaningful impacts to occupied habitats downstream or would measurably or
meaningfully impact the listed fish. Given these factors, activities on the parcel would have no
effect for the listed Colorado River endangered fish species and their Critical Habitats.
Monarch butterfly – Candidate. Candidate species are not afforded full protection under the ESA;
however, the USFWS encourages their consideration in environmental planning, and the USFWS
regulatory guidance indicates that Candidate species should be treated similarly to Proposed
Species with regard to inter-agency consultation requirements. Informal consultation is requested
when a provisional “is likely to jeopardize” determination is reached for a Candidate species
(USFWS 1998).
Monarch butterfly adults feed (gather nectar) from a variety of flowering plant species. However,
the monarch butterfly only lays eggs and larvae only feed on milkweeds (Asclepias spp.). The
western population overwinters in various coastal sites in central and southern California, and
central populations overwinter in Mexico. Monarchs have multiple generations during their
migrations; the second, third and fourth generations return to their northern locations in the
United States and Canada in the spring.
The project area contains migratory and overwintering habitat for the monarch butterfly. Showy
milkweed (Asclepias speciosa) is an abundant component of the vegetation in the transitional
zones along the boundaries of the wetland areas. Adult butterflies and several monarch caterpillars
were observed feeding on milkweeds at the western edge of the property. Western Colorado is
not part of a major monarch migration corridor, but the site is being used by migrating adults and
as a potential overwintering site for the dispersed population in the area.
Proposed development would mostly occur outside the mesic/wetland meadows where the
majority of milkweed is located, therefore direct impacts to host plants and habitats would be
mostly avoided. The project would result in the complete loss of vegetation from approximately
20 acres of the property, which would result in potential direct impacts to chrysalis and caterpillars
and reduce the foraging vegetation available to adult butterflies. This may result in minor, localized
impacts to migrating monarch butterflies, and may reduce the attractiveness of the site as an egg-
laying site.
Development of the parcel is not likely to jeopardize this Candidate species, as the project may
affect individuals but is not expected to alter the species’ overall range and life history patterns.
USFWS consultation is not required by ESA for Candidate species where an action is not likely to
jeopardize the species’ existence.
Ute Ladies’-Tresses - Threatened. The project area occurs outside the known range of the Ute
ladies’-tresses orchid, and is a significant distance from the nearest known populations in the
Roaring Fork Valley. The parcel does contain wet meadow conditions that are potentially suitable
habitat for the species, although similar habitats in the Colorado River valley have been searched
Wetland Delineation Report
Rifle Gravel Pit #1 February 2022
26
repeatedly and no orchids have ever been located. The potential habitats on the parcel have been
incidentally evaluated by a trained and experienced orchid surveyor in the course of wetland
assessments, and no orchids have been located. However, no systematic survey meeting USFWS
standards has been undertaken on the parcel at this time. Activities on the parcel are not expected
to directly impact effective habitats since the wetland areas would be avoided, and as previously
discussed the project would not substantially change the existing hydrology that supports these
wetlands. Given the location outside of the known range, and the avoidance of impacts to
potentially-suitable habitat, activities on the parcel would have no effect on the Ute ladies’-tresses
orchid.
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Rifle Gravel Pit #1 February 2022
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6. REFERENCES
Colorado Parks and Wildlife (CPW). 2020. Recommended Buffer Zones and Seasonal Restrictions for
Colorado Raptors (2020). Available at:
https://cpw.state.co.us/Documents/WildlifeSpecies/LivingWithWildlife/Raptor-Buffer-
Guidelines.pdf
Environmental Protection Agency (EPA). 2020. Joint Memorandum to the Field between the U.S. Department
of the Army, Corps of Engineers and the U.S. Environmental Protection Agency concerning exempt
construction or maintenance of irrigation ditches and exempt maintenance of drainage ditches
under Section 404 of the Clean Water Act. Available at:
https://www.epa.gov/sites/default/files/2020-
07/documents/final_ditch_exemption_memo_july_2020_with_epa.pdf
Lichvar, R.W., D.L. Banks, W.N. Kirchner, and N.C. Melvin. 2016. The National Wetland Plant List: 2016
wetland ratings. Phytoneuron 2016-30: 1-17. Published 28 April 2016. ISSN 2153 733X Natural
Resource Conservation Service. 2017. SSUGO Database.
National Resource Conservation Service (NRCS). 2021. Web Soil Survey. Available at:
https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_053627
United States Army Corps of Engineers (USACE), Environmental Laboratory. 1987. Corps of Engineers
Wetland Delineation Manual. Wetlands Research Program Technical Report Y-87-1.
USACE. 2008. Environmental Laboratory, Regional Supplement to the Corps of Engineers Wetland
Delineation Manual: Arid West Region (V.2, ERDC/EL TR-08-28). US Army Engineer Research and
Development Center. Vicksburg, MS.
USACE. 2005. Regulatory Guidance Letter No. 05-05. Ordinary High Water Mark Identification. December 7,
2005.
United States Department of Agriculture (USDA), Soil Survey Staff. 2015. Illustrated guide to soil taxonomy,
version 2. U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil
Survey Center, Lincoln, Nebraska.
USDA. 2021. U.S. Drought Monitor, July 20, 2021. Available at:
https://droughtmonitor.unl.edu/Maps/MapArchive.aspx. Accessed August 2021.
U.S. Fish and Wildlife Service (USFWS). 1998. Endangered Species Consultation Handbook: procedures for
conducting consultation and conference activities under Section 7 of the Endangered Species Act.
Washington, D.C. Published March 1998.
United States Fish and Wildlife Service (USFWS). 2022. Information for Planning and Consultation (IPaC).
Available at: https://ecos.fws.gov/ipac/. Accessed January 2022.
Western Regional Climate Center. 2019. Regional Climate Summaries. Available at:
http://www.wrcc.dri.edu/. Accessed August 2021.
DEPARTMENT OF THE ARMY
U.S. ARMY CORPS OF ENGINEERS, ALBUQUERQUE DISTRICT
400 ROOD AVENUE, ROOM 224
GRAND JUNCTION, CO 81501-2520
July 27, 2022
Regulatory Division (SPK-2020-00172)
SUBJECT: Aquatic Resource Boundary Confirmation
IHC Scott
Attn: Tony Roberts
9200 E Mineral Ave
Centennial, CO 80112
troberts@scottcontracting.com
Dear Mr. Roberts:
We are responding to your request for verification of an aquatic resource delineation
for the Rifle Gravel Pit #1 site. The 50.4-acre project site is located approximately 3
miles east of the Town of Rifle, directly north of Interstate 70, within the SW ¼ SE ¼ of
Section 8, Township 6 South, Range 92 West, Sixth Principal Meridian, latitude
39.53368°, longitude -107.69272°, Garfield County, Colorado.
Based on available information, we concur with your aquatic resource delineation for
the site, which consists of approximately 18.28 acres of palustrine emergent wetland
and 1.13 acres of non-wetland open water (irrigation tailwater ditch), as depicted on the
enclosed February 8, 2022, Delineated Aquatic Resources, prepared by SGM,
Incorporated (Enclosure 1).
This verification letter does not constitute a determination of jurisdiction (JD). A JD is
not required to process an application for a Department of the Army permit. If you do not
require a JD for the site, your permit application may be processed sooner . You may
request a JD for this site at any time prior to starting work in aquatic resources,
including after a permit decision is made. To request a JD for this site, complete the
attached Request for Jurisdictional Determination Form (Enclosure 2) and return it to
this office at the address listed below.
Please refer to identification number SPA-2022-00172 in any correspondence
concerning this project. If you have any questions, please contact me at the
Northwestern Colorado Branch, 400 Rood Avenue, Room 224, Grand Junction,
Colorado 81501, by email at Tyler.R.Adams@usace.army.mil, or telephone at
-2-
(970) 243-1199, extension 1013. To complete our Customer Service Survey, visit our
website at: https://regulatory.ops.usace.army.mil/customer-service-survey/
Sincerely,
Tyler R. Adams
Project Manager
NW Colorado Branch
Enclosures
cc:
Glenn Hartmann, Garfield County, ghartmann@garfield-county.com
Lucas West, Division of Reclamation, Mining and Safety, lucas.west@state.co.us
Alex Nees, SGM, Inc., alexn@sgm-inc.com
Ditch OHWM1.13 acres
Wetland A2.05 acres
Wetland B0.14 acres
Wetland C0.02 acres
Wetland D6 acres
Wetland E9.86 acres
Wetland F0.21 acres
17
07
08
6S 92W
SCALE:
This product is for informational purposes and may not have beenprepared for, or be suitable for legal, engineering, or surveying purposes.Users of this information should review or consult the primary data andinformation sources to ascertain the usability of the information. The mapsare distributed "AS-IS" without warranties of any kind, either expressed orimplied, including but not limited to warranties of suitability to a particularpurpose or use.
Disclaimer:
Delineated Aquatic Resources
Rifle Pit Project
LEGEND
Date:2/8/2022Location:Rifle/Silt, CO
Drawn By:RKKCreated By:SGM
UV65
UV82
UV13
UV325
UV330
UV133
Carbonate
Parachute
Rifle
NewCastle GlenwoodSprings
Collbran
Carbondale
De Beque
Silt
¯
US or State Highway
County Highway
Township/Range/Section
Area of Investigation
Project Location
0 325 650162.5
Feet1 in = 365 feet
Delineated Wetlands
Last Chance Ditch Lateral
PEM Wetlands
Encl 1
IHC Scott – Rifle Gravel Pit #1 May 2022
Garfield County Special Use Permit Application Appendix I
Appendix I – Weed Management Plan
WEED MANAGEMENT PLAN
RIFLE PIT #1
IHC SCOTT (SCOTT CONTRACTING INC.)
MARCH 2021
Prepared by
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004
970.945.5948 fax
Weed Management Plan March 2021
i
TABLE OF CONTENTS
1.0 Summary 1
2.0 Description of Survey Area 2
3.0 Results of Surveys 3
4.0 Noxious Weed Management Recommendations 7
LIST OF FIGURES
Figure 1. Project Area Existing Conditions 4
Figure 2. Russian Olive Occurrences 5
Figure 3. Other Noxious Weed Occurrences 6
LIST OF APPENDICES
Appendix A – State of Colorado Noxious Weeds
Appendix B – Garfield County Noxious Weeds