HomeMy WebLinkAboutRanch Main House Drainage MemoSweetwater Ranch Main Residence
Drainage Memorandum
To: Chris Bendon
From:Jesse K. Swann, PE
Date: June 30,2025
Re: Drainage Memo-Sweetwater Ranch Main Residence
Encl: Appendix
Sopris Engineering LLC (SE) has prepared this drainage memo in support of the Grading & Building permit applications for
a single-family residence located in Gadield County, The proposed residence is situated on Tract G-2, which
encompasses 41.65 acres within the SB35 Subdivision Exemption Plat. The SB35 Subdivision is a recently recorded
subdivision consisting of several parcels, each exceeding 35 acres, all located within an active 2,659+l- acre working
ranch under common ownership.
This memo includes a description of the existing site conditions, proposed improvements, and the general approach to
stormwater routing, considering the open expansiveness of the ranch and surrounding area.
Section A-Existinq Site Overview:
The existing site is located approximately 0.9 miles west of Sweetwater Road, Access to this pottion of the ranch is
cunently available via a private gravel road that extends from Sweetwater Road through the ranch. The SB35 Subdivision
is a working ranch that will continue operations involving cattle raising and hay production. lmprovements to the existing
gravel access road, including an extension to serve the proposed residence and other structures are currently under
review by the U.S. Army Corps of Engineers, Garfield County, and Eagle County. The design of the road has been
coordinated and approved by the Gypsum Fire District.
The surrounding topography consists of relatively hilly terrain, with slopes ranging from 10% to 20o/o, generally trending
east to northeast. Vegetation in the area includes pinyon pine, Gambel oak, and sagebrush, along with cultivated pastures
featuring several lateral irrigation ditches used for flood irrigation.
Sweetwater Creek, located approximately 0.8 miles east of the proposed residence site (as the crow flies), is the ultimate
receiving waterbody. Although Sweetwater Creek is not included in FEMA Flood lnsurance Rate Maps, floodplain studies
conducted in anticipation of future bridge crossings indicate that the 100-year floodway and floodplain remain confined
near the ordinary high-water mark, all of which are well below the proposed residential site, Surface runoff from the
building site follows existing drainage patterns, which are conveyed over and through irrigated pastures and areas of
partially vegetated ground cover typical of high-elevation, arid environments. Figure 1 is provided to illustrate the
proposed loca.tion of the residence and su area
Figure 1'Aerial lmage of
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Drainage Memorandum
Sweetwater Ranch Main Residence
Section B-Proiect Overview:
The proposed project involves the construction of a single-family residence, attached garage, dual driveways, patios, utility
improvements, stormwater mitigation measures, and landscaping enhancements. Sur{ace treatment for the driveways will
primarily consist of chip and seal, with a concrete apron at the entrance to the garage. The landscaping will be designed to
complement the surrounding vegetation and will be inigated using water supplied from Beaver Reseruoir, located
approximately 0.5 miles west of the site on the SB35 Subdivision propefiy.
Grading activities will be carefully planned to minimize disturbance to existing topography and vegetation. Cut and fill
operations will be conducted in accordance with best management practices (BMPs) to ensure erosion control and
sediment containment during construction. Temporary sediment control measures, such as sediment control logs and silt
fences, will be implemented around the site to prevent sediment migration from the development area and to protect
existing watenruays and drainage courses.
Additionally, erosion and.sediment control BMPs will be maintained throughout construction, with inspections conducted in
compliance with the State issued Storm Water Management Plan permit, regularly to ensure their effectiveness. Final
grading will be completed to promote positive drainage away from the residence, reducing the potential for ponding or
surface runoff issues, After construction is complete, disturbed areas will be stabilized through landscaping and
revegetation to prevent erosion and establish permanent ground cover.
Section C Existinq Drainaqe Basin Analvsis:
An analysis of the existing drainage conditions was conducted to estimate current peak stormwater flow rates within the
development area, This assessment was based on topographic survey data and field observations. Key discharge
locations, or design points, were identified to facilitate comparisons between pre- and post-development drainage
conditions. The existing delineated drainage basins and associated design points are described below and illustrated on
Exhibit A attached to this memo,
The building site is proposed on a natural topographic knoll, which effectively diverts offsite stormwater flows around the
site-either to the north or south. As a result, offsite flows do not impact the site and will continue following existing
drainage patterns, As a result, the existing drainage analysis focuses exclusively on onsite conditions, as furlher described
below and illustrated on Exhibit A. The limits of the existing onsite basins were defined to correspond with the area
proposed for disturbance related to the development of the residence.
. Existing North Basin: This basin drains to the north side of the ridgeline where the proposed residence will be
located. The area is vegetated with arid grasses and shrubs. Stormwater runoff flows nofthward towards the HMS
irrigation ditch and ultimately toward Sweetwater Creek, Drainage Point (DP-'l) generally coincides with'a
proposed d ischarge location for post-development ru noff.
. Existing South Basin: Located on the southern porlion of the development area, this basin features similar
vegetation with slightly more grass cover. Historically, stormwater flows overland toward an intermittent drainage
swale at Design Point (DP-2), eventually discharging into the HMS irrigation ditch and/or Sweetwater Creek.
The delineated existing drainage basins were used to estimate peak runoff rates, which serve as a basis for comparison
against post-development conditions, Hydrologic methods, assumptions, and results are summarized in Section E of this
memo.
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pg.2
Drainage Memorandum
Sweetwater Ranch Main Residence
Section D-Post Development Drainaqe Analvsis:
To properly size the proposed storm water mitigation infrastructure for the project, the post development site was divided
into several drainage basins and sub-basins, The overall basin limits remain unchanged as compared to the existing
onsite drainage basin delineations. The post development drainage basins and sub-basins are described in detail below.
North Basins - Desiqn Point 1
Nodh Dra aoe Basin-The North Basin accounts for the developed site that will route runoff towards DP-1. ln
supporl of sizing stormwater infrastructure this basin was broken into several sub-basins as described below,
' Post N.1 is a small, landscaped area adjacent to the main entrance to the residence. Runoff will be collected
within a landscape area inlet and connected to a lateral storm drain connected to the main nofth drainpipe that
conveys, and discharges flows to DP-1.
Post N.1.1 is a small landscape area that drains to a landscape area inlet and connected to the same lateral
storm drain as Post N-1,
Post N-1.2 is similar and connected to the same lateral storm pipe as N-1.
Post N-2 is a larger onsite basin that consists of landscaped area and porlions of the north driveway and gravel
parking stalls. Storm water from this basin will be routed to an area inlet located at the base of a drainage
swale integrated with the sunounding topography and landscaping, This inlet is the upstream inlet associated
with the main nofth storm drain system.
Post N.3 is located between the formal entrance to the residence and the main wing, The area primarily
consists of landscaping and concrete access walks. Runoff will be conveyed to a landscape area inlet which is
connected to the north main storm drainpipe.
Post N.4 is located on either side of the architectural bridge that connects the main wing with the main
residence. This basin consists of a landscaping area and runoff will be conveyed to a landscape area inlet
located under and near the architectural bridge,
Post N.5 is a small, landscaped basin with several large rocks, a fire pit, and patio area, Runoff from this basin
will be routed to a small landscape area inlet connected to a lateral storm pipe connected to the north main
storm line.
Post N.6 includes the portion of the North Basin that does not contribute flows to the north storm drain system,
lnstead, runoff from this basin will sheet flow to the north,
Nofth Roof Drain Basinsl Roof drainage basins connected to the north storm drain system include Roof 1 -
Roof 3 as illustrated on Exhibit A. These roof areas will be collected by roof inlets or gutters which will be
connected directly to the north storm drain system via downspouts or lateral storm drains picking up internal
routing of drain lines,
South Basins - Desiqn Point 2
South Drainaqe Basin - The South Basin accounts for the developed site that will route runoff towards DP-2. ln
support of sizing stormwater infrastructure this basin was broken into several subbasins as described below.
Post S-1 is a large, landscaped area located along the west side of the south motorcoutt. Stormwater is
directed towards an area inlet located east of the south driveway. The inlet serves as the fufthest upstream
portion of the main south storm drain system.
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pg.3
Drainage Memorandum
Sweetwater Ranch Main Residence
Post S.2 consists of a portion of the southern chip and seal driveway and concrete apron. Runoff from this
basin will be collected by a lineal trench drain along the entrance to the garage.
Post S-3 consists of a small landscaping area located west of the south motorcoutt and upper reach of the
water feature. located near
Post S.4 is a landscape area that lies between the main residence and guest wing. Runoff from this basin will
sheet flow towards a proposed inlet located near the re-circulating water feature,
Post S.5 is a small basin to the east of the building collecting stormwater from impervious patio areas via slot
drains served by a lateral storm drain connected to the main south drainpipe,
Post 3.6 is a basin that accounts for all the stormwater within the South Basin that doesn't get collected by the
proposed south storm drain system, Runoff will be directed over the sudace and towards DP-2,
South Roof Drain Basins: Roof drainage basins connected to the south storm drain system include Roof 4 -
Roof 7 as illustrated on Exhibit A, These roof areas will be collected by roof inlets or gutters which will be
connected directly to the north storm drain system via downspouts or lateral storm drains picking up internal
routing of drain lines.
Culvert A,Basin includes the tributary area conveying runoff to the proposed culveft (Culveft A) under the
southern driveway. This culvert will also be conveying offsite flows from the upgradient culveft that was sized
under a separate permit. The resultant flow for the upstream was determined to be 7 .24 cfs for the 100-year storm
event. This flow was included in sizing Culvert A,
The methodology for estimating post development peak runoff rates is discussed in Section E below and the
results are summarized within Table 2.
Section E-Hvdrolosic Methods and Assumptions:
Existing and post-development drainage areas were analyzed using the Rational Method (Equation 1) since the
cumulative total of tributary areas are less than 90 acres,
Equation 1: Q= C* l* A
Q= Runoff Flow Rate (cfs); C= Runoff Coefficient
l= Rainfall lntensity (in/h\; A= Area of Basin (acres)
The runoff coefficient (C) represents the ratio of runoff volume to rainfall volume during a storm event. lts determination is
influenced by several factors, including soil type, the percentage of impervious area within the watershed, and the
frequency of storm events, Each drainage basin was analyzed to quantify its percentage of impervious area.
The effective impervious area for each basin was then used to derive a weighted runoff coefficient. A spreadsheet tool
developed by the Mile High Flood District (MHFD) of Denver, CO was used to calculate site-specific runoff coefficients.
This tool allows for the calculation of site-specific C values based on a Type C hydrologic soil classification.
The MHFD spreadsheet, which is included in Appendix, also computes the time of concentration (Tc), the time it takes for
runoff to travel from the furthest point upstream in a basin to the designated design point, accounting for both overland and
channelized flow. A minimum time of concentration of 5 minutes was adopted for the smaller developed tributary areas.
The calculated Tc for post development basins was rounded down to the nearest 5 minutes, which is a conservative
approach, while maintaining a minimum time of concentration of 5 minutes. These Tc values were then used to estimate
the corresponding 100-year rainfall intensities based on NOAA rainfall data for the surrounding area,
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pg,4
Drainage Memorandum
$weetwater Ranch Main Residence
Tables I and2, provided below, presents the Areas, C values, Tc, lntensities and resultant'100-year peak runoff rates for
both the existing and postdevelopment drainage basins.
Table 1-Existinq Peak 10Ollear Xuno Xates
Trble 1: Edsfiing llrainwc: Ratioaal f,llcthod Sumnrary
lhainage Basin lD Area
{ac)
Perc€nt
lmperviou*
Runoff
Coefficient, C Sele{td
rc {min}
Rainl|ll
lnten5ity
{infftrl
Feok Flw,
e {cfs}
lQ6-yt lB0.yr f lil)-yr
Dil{SRlH t-45 2%049 14 1 4.39 3.13
EX€SI.'TH 1,43 2%tl 49 172 358 2-G0
Table 2-Post Development Peak 1O0-Year Runoff Rates
Drainag* Basin lD Area
{ac}
Percent
lmpervious
Runoff
Coefficient, C Se.lected
Ic{min}
Rainfall
lntensity
{inlhr}
Peak Florfl;
O {cfs}
1{Xt-yr llXhr l0l)-yr
FOST DEVELOPIIEIIT OHSITE SUB BASIIIS
POSTt4-1.0 0,0105 2,W6 0.4s 5 708 0.$2
P05T ir-1_1 0.029 :15"890 a"&7 5 7 {Nt 0.r{
POST ll-12 0 011 48.8ry6 0_s8 5 7_0t!s.05
POSr r{-2 0_445 25.9Vs 0.59 1S 5_18 i-36
FOSTr.r-3 o_038 37"5%0.64 5 7.&8 0"t1
POSr lt4 0"038 2,8%0.49 5 7ffi 0.t3
rcsTr,r-5 0,020 23.1%0"58 5 7.08 0,s8
POSrH$0,807 30.7%5.r8 255
POSTgI o4:]7.9%0.52 5 7"08 1.58
POSrS-2 0,'t2 l$0.09o 0.89 5 7.08 0.7t
P05r93 0.0N zooh 0.49 5 7.08 0.$t
PAST54 o02 2.O%0.49 1S 5t8 0.r5
POSr$5 o02 r00.0%0"89 q./08 0.11
POST56 049 7,t)8 1.12
CUL\'€RTA o25 24.1%0-58 5 708 1.O{
ROOF EA$11{S
RO0F-1 0"{F 100-0%0,89 5 7.08 o.{0
R00F-2 o.04 r08_0%8,89 5 7.0t1 023
ROOF-3 0.03 r00"0%0.89 5 70€a.:2.
ROOF.4 0.07 10s,0%0.8s 5 7$B 016
ROOF.5 o{x}t00.0%089 5 7ffi o-50
ROOFS 0.06 100.0%08s 5 7.&8 0.33
ROOF-7 0-€100.0%0,89 5 7m 0.{9
Section F-Hvdraulic Methods and Assumptions:
The 100-year posldevelopment peak runoff rates summarized in Table 2 were used to size the proposed stormwater
conveyance system, which primarily includes inlets, drainpipes, and a single culvert beneath the south driveway.
Storm Sewer Sizinq: All stormwater drainpipes were designed to accommodate the 10O-year peak runoff rates as outlined
in Table 2, The Hydraflow software, an Autodesk application for sizing pipes and culverts, was employed to determine
appropriate pipe sizes for this project. Hydraflow utilizes Manning's Equation (Equation 2) to calculate the maximum
capacities of the pipes,
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Drainage Memorandum
Sweetwater Ranch Main Residence
Equation 2: Q= 1'49/n * R2/3 * A * So5
Q = Runoff Flow Rate (cfs); n = Manning's Roughness Coefficient
R = Hydraulic Radlus (ft); A= Flow Area (sD, S = Channel Slope (ft/ft)
The approach to confirming pipe sizes for this project involved assessing the capacity of proposed pipe sizes based on a
minimum design slope of 2%. The capacity of each pipe size was then referenced to determine the appropriate pipe
diameter, considering the cumulative tributary flows. Table 3 below summarizes the approximate capacity of pipes
operating at 80% full for sizes ranging from 4 inches to 12 inches, Supporting calculations are provided in the Appendix,
lnlet Sizinq: lnlets are proposed at multiple locations throughout the project to effectively capture and convey stormwater
runoff away from the proposed residence. The Orifice Equation (Eq. 3) was used to estimate the required grate area for
each inlet, All inlets are designed to accommodate the 100-year peak runoff rates, incorporating a 50% clogging factor
based on the available head (depth) associated with each inlet. lnlet capacities for the various sizes proposed are
summarized in Table 4.
Equation3: Q = CoA-sqrt(2gh)
Q= Orifice Flow Rate (cfs); Ca= Orifice Coefficient;(0.61)
g = acceleration from gravt$; A= area of orifice (sf),
h = head acting on the centerline (ft)
Table 4-lnlet Capacitv Summarv
Culvert Sizinq: Hydraflow Express Extension was used to size the single culvert located beneath the southern driveway.
Hydraflow Express employs an energy-based Standard Step methodology to estimate culvert flow capacities. For
maintenance and efficiency purposes, a minimum culvert diameter of 18 inches was adopted, The proposed culveft will
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pg,6
Drainage Memorandum
Sweetwater Ranch Main Residence
be constructed from ADS N-12 smooth interiorpipe, utilizing a Manning's Roughness Coefficientof 0,013, which reflects
the flow roughness characteristics of the pipe material
To accurately estimate the culvert capacity, flow increments of 0.10 cubic feet per second (cfs) were evaluated iteratively
untiljust prior to roadway overtopping. These flow estimates were cross-referenced with the total 100-year peak runoff
rate tributary to the culvert. lt is important to note that the offsite peak runoff rate tributary to this culvert was obtained from
a previous drainage memo prepared by our office in support of the permitting and construction of the proposed private
access road. This additionalflow is specific to Culvert #5, as outlined in our Road 3 Drainage Memo dated 05-01-2025.
When combined with the onsite tributary flow, the total 100-year flow tributary to the culvert is approximately 8,28 cfs.
Table 5 summarizes the tributary peak runoff rates, the corresponding culvert capacities based on size, depth, material,
and slope. Supporting calculations are provided in the Appendix.
Table 5-Culvert Sizing Summarv
Section G-Erosion Control:
Erosion control measures are essential to mitigate drainage issues and prevent soil erosion during construction activities.
While the responsibility for implementing these measures lies with the Contractor under the State-issued Stormwater
Management Plan, the following erosion control practices are minimum recommendations to help reduce sediment
transport and soil degradation.
Construction activities inevitably create a risk of soil erosion and offsite sediment transport, particularly during rain events.
To combat this, the contractor must install and maintain the following Best Management Practices (BMPs) throughout the
construction phase:
. Pre.Construction Measures: Before any clearing, grubbing, lot grading, or construction work begins, the
contractor shall establish temporary sediment control logs and/or embedded silt fencing around the anticipated
limits of disturbance.. Culved Protection: Hay bales and sediment control logs should be placed at the inlets and outlets of all
culverts to prevent sediment from contaminating the culverts prior to the establishment of vegetation.
. Topsoil Management: Topsoil designated for removal and reuse shall be stockpiled with sediment control logs
or silt fencing around their perimeters. lf stockpiles are to remain for more than 15 days, temporary seed should
be applied to prevent erosion and weed growth,
. Ditch Control: lnstall sediment control logs within the flowline of ditches at appropriate intervals to reduce flow
velocities and capture sediment,. Site lnspections: The site must be inspected and recorded in accordance with the State issued SWMP. Silt
deposits behind silt fencing and sediment control logs should be regularly cleared to ensure the effectiveness of
the erosion control system, These inspections and maintenance activities must be documented in a logbook
readily available for inspection.
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pg,6
Drainage Memorandum
Sweetwater Ranch Main Resldence
Vegetation Establishment: Seed and mulch shall be applied over disturbed cut and fill slopes, with watering as
necessary, to establish permanent vegetative ground cover,
Slope Stabilization: Erosion control blankets and/or hydromulching shall be applied to all cut and fill slopes that
exceed a 3:1 slope ratio.
Vehicle Tracking Control: Vehicle tracking control devises shall be installed at the entrance to Sweetwater
Road to prevent tracking onto the public roadways.
Temporary erosion control measures installed during construction should remain in place and be maintained until new
vegetation is established at a 70% growth level. Once soil stabilization is satisfactory, temporary erosion control
structures may be removed.
Given the dynamic nature of construction sites, the final location and selection of BMPs shall be at the contractor's
discretion. All necessary permits must be acquired prior to the commencement of construction, and the criteria outlined in
these permits must be adhered to until the associated permits are closed.
Section H-Conclusions:
The drainage analysis indicates that the proposed improvements will not adversely impact the subject propefty or
surrounding areas. Onsite runoff will be appropriately managed via the proposed drainage system which has been sized
to safely convey the 100-year storm event associated with the proposed development. Lastly, erosion control BMPs will
be enforced prior throughout construction in compliance with State issued SWMP permit.
For further questions or additional information, please feel free to contact me.
Prepared by: Jesse K. Swann, PE
Encl Exhibit A: Existing Drainage Basin Delineation Map
Exhibit B: Post Development Drainage Basin Delineation Map
NOAA Rainfall Depth Chart
Hydraflow Pipe Capacity Calcs
Hydraflow Culvert Hydraulic Calcs
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06-30-2425
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Precipitation Frequency Data Seler https://hdsc.nws.noaa.gov/pfds/pfdsjrintpage.html?lat=39.7 551&lon:...
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NOAA Atlas 14, Volume 8, Version 2
Location name: Gypsum, Golorado, USA*
Latitude: 39.7551", Longitude: -107.1036"
Elevation: 6997 ft**
* source: ESRI l\4aps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Deborah Martin, Sandra Pavlovic, lshani Roy, lvlichael st. Laurent, Carl Trypaluk, Dale
Unruh, l/ichael Yelda, Geoffery Bonnin
NOA,A National Weaiher Seruice, Silver Spring, lvlaryland
PE_tabular I PE_graphjcal I Maps_&_eeitels
PF tabular
PDS-based int IOn uen estimates with 90% confidence intervals n inches/hou 1
recurrence interval
1 2 5 10 25 50 100 200 500 1000
5-min 1.62 2.10 2.96 3.77 4.97 5.99 7.08 8.27
.oo- tz
9.96 1'l.3
1A-171.84-6 1
10-min 1.19 1.54 2.17 2.75 3.64 4.3S 5.18 6.05 7.30 8.30
1.24-1 73-2 -4 10 7 1 5-8 11
15-min 0.964 't.25 1.77 2.24 2.96 3.56 4.22 4.92 5.93 6.75
1 1.00-1 -7.31 11 -1
30-min 0.608 0.800 1.12 1.40 1.79 2.10 2.42 2.75 3.21 3.56
11-1 1.37-2 1
60-min 0.384 0.486 0.655 o.797 0.996
759-1.34
1.15 1.31 1.47
.00-2.1
2-hr 0.232 0.286 0.375
.302-0.4
0.448 0.549 0.626 o.704 0.783 0.887 0.966
.421-O -t.'17-1
3-hr 0.178 0.2'11 0.266 o.312 0.376 0.427 0.478 0.531 0.602 0.656
1 .21 .291-O -0.
6-hr o.114 0.130
1 06-0.1
0.,l56
128-0.1
0.180 0.212 0.239
182-0.31
0.266 0.295 0.334 0.365
1 66-0
12-hr 0.o71 0.081 0.098
.o81-O.121
0.113 0.134
106-0.174
0.151
116-0.1
0.168 0.187 0.212 0.231
-0.1 1 143-O 1
24-hr o.044 0.050 0.061 o.071 0.084 0.095 0.107 0.119 0.135
.092-0.194
0.148
.051 -0.'1 124 1 1
2-day o.o27 0.030 0.037 o.o42 0.050 0.057 0.064 o.o71 0.081 0.089
1 11 1
3-day 0.020 0.023 0.028 0.032 0.038 0.043 0.048 0.053 0.06'l 0.066
17 -0.048)
0.016 0.019 0.023 0.026 0.031 0.035 0.039 0.043 0.049 0.053
I .051
0.01'l
'10-0.01
0.015 0.0'17 0.020 0.023 0.025 o.o27 0.03'l 0.034
14-O.O21 01 8-0 19-0
10-day 0.009 0.010 o.o12 0.013 0.016 0.017 0.019 0.021 o.024 0.026
-0.01 3-0.01 '14-o 15-0 7 .017
20-day 0.006 0.007 0.008 0.009 0.010 0.011 0.0'12
10-0.01
0.014 0.015 0.016
I 4 .01 1
30-day 0.005 0.005 0.006 0.007 0.008 0.009 0.010 0.011 o.o12 0.013
-0.01 11
45-day 0.005 0.005 0.006 0.007 0.007 0.008
.006-0.0'1
0.009 0.010 0.0't 0
.005-0 -0.01
60-day 0.003 0.004 0.005 0.005 0.006 0.006 0.007 0.007 0.008
.006-0.011
0.009
.004 .004-0
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
\umbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates
lfor a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds
tre not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
rlease refer to NOAA Atlas 14 document for more information.
lof4
PF graphical
1011712024,10:15 AM
Ghannel Report
Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc.
4{NCH 80% CAPACITY
Gircular
Diameter (ft)= 0.33
lnvert Elev (ft)
Slope (%)
N-Value
=Q.
=Q.
=Q.
=?
=Q.
=Q.
=Q.
=Q.
3
00
00
01
=l=l
=Q
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (ft)
Saturday, Jun282025
26
256
07
49
73
29
26
45
Section
Calculations
Compute by:
Known Depth (ft)
Elev (ft)
2.00
1.75
1.50
1.25
1.00
Known Depth
= 0.26
v
10
0.75
Reach (ft)
Ghannel Report
Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc.
6{NCH 80% CAPACITY
Circular
Diameter (ft)= 0.50
lnvert Elev (ft)
Slope (%)
N-Value
Galculations
Compute by:
Known Depth (ft)
Elev (ft)
2.00
= 1.00
= 2.O0
= 0.013
Known Depth
= 0.40
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (ft)
Saturday, Jun282O25
.40
.775
.17
.60
Section
11
.44
.40
.73
=Q
=Q
=Q
=d
=l
=Q
=Q
=Q
1.75
1.50
1.25
1.00
0 1
0.75
Reach (ft)
Channel Report
Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc.
8.INCH 80% CAPACITY
Gircular
Diameter (ft)
lnveft Elev (ft)
Slope (%)
N-Value
Calculations
Compute by:
Known Depth (ft)
Elev (ft)
2.00
= 0.67
= 1.00
= 2.00
= 0.013
Known Depth
= 0.54
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ftls)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (ft)
Saturday, Jun282025
0.54
1.692
0.30
5.60
1.48
0.60
Section
0.54
1.02
1.75
1.50
1.25
1.00
v
/
0 1
0.75
Reach (ft)
Ghannel Report
Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc.
1o{NcH 80% GAPACITY
Circular
Diameter (ft)= 0.83
Invert Elev (ft)
Slope (%)
N-Value
= 0.66
= 2.996
= 0.46
= 6.45
= 1.84
= 0.75
= 0.66
= 1.31
= 1.00
= 2.00
= 0.013
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ftls)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (f0
Saturday, Jun282025
Section
Calculations
Compute by:
Known Depth (ft)
Elev (ft)
2.00
1.75
1.50
1.25
1.00
Known Depth
= 0.66
0 I
0.75
Reach (ft)
Ghannel Report
Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc.
12-|NGH 800/o CAPACITY
Circular
Diameter (ft)= 1.00
lnvert Elev (ft)
Slope (%)
N-Value
Saturday, Jun 28 2025
5
.80
.92
.67
.31
.22
.92
0
4
0
7
2
03
00
00
01
=f
=)
=Q
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (f0
= 0.80
= 1.63Calculations
Compute by:
Known Depth (ft)
Elev (ft)
3.00
2.50
2.00
1.50
1.00
Known Depth
= 0.80
Section Depth (ft)
2.00
1.50
1.00
0.50
0.00
320
0.50
Reach (ft)
-0.50
Gulvert Report
Hydraflow Express Extension for Autodesk@ Civil 3D@ by Autodesk, lnc.
Culvert A Main Residence
lnvert Elev Dn (ft)
Pipe Length (f0
Slope (%)
Invert Elev Up (ft)
Rise (in)
Shape
Span (in)
No. Barrels
n-Value
Culvert Type
Culvert Entrance
Coeff. K,M,c,Y,k
Embankment
Top Elevation (ft)
Top Width (ft)
Crest Width (f0
= 7692.17
= 28.55
= 2.00
= 7692.74
= 18.0
= Circular
= 18.0
=l
= 0.013
= Circular Culvert
= Rough tapered inlet throat
= 0.519, 0.64, 0.021, 0.9, 0.5
= 7695.41
= 20.00
= 10.00
C{hnr*kltr FoddonE
rot
-
HGL
Calculations
Qmin (cfs)
Qmax (cfs)
Tailwater Elev (ft)
Highlighted
Qtotal (cfs)
Qpipe (cfs)
Qovertop (cfs)
Veloc Dn (fUs)
Veloc Up (ft/s)
HGL Dn (ft)
HGL Up (ft)
Hw Elev (ft)
Hw/D (ft)
Flow Regime
Saturday, Jun282025
= 14.00
= 15.00
= (dc+D)/2
= 14.10
= 14.10
= 0.00
= 8.08
= 8.28
= 7693.61
= 7694.12
= 7695.41
= 1.78
= lnlet Control
Ela (n0
ffi.s
rbBob {D
7696.6
t66{.S0
?!s.€6
?@t.*
7f'2'.
3.25
2XA
r18
o26
-o.74
-1.7a
35 58
R@h {i}
d.stuCde6rt
-
Enbd*