HomeMy WebLinkAboutCorrespondenceGlenn Hartmann
From:
Sent:
To:
Cc:
Subiect:
Attachments:
JON FREDERICKS <jon@landwestcolorado.com >
Thursday, March 10,2022 2:16 PM
Glenn Hartmann
Chris Hale (chris@mountaincross-eng.com); Danny Stewart (dannys@rfeng.biz); Martin
Van Ardenne; Jody Edwards fiee@kceclaw.com)
lExternall RE: lExternal] Spring Valley Ranch PUD Grading Permit
SVR-cu lvert-ca lcu lations.pdf
Glenn,
ln response to the question regarding the culvert calculations, I have attached some relevant pages from the Engineers
Report of the Final Plat application (Appendix Q). Here is a summary:
¡ The proposed culvert drains "Basin 15" from the map on page 9.
o The 100-year peak discharge for Basin 15 is 0.3O7 CFS per the Table on page 10.
o The culvert report on page L2 shows that an 18" culvert at 2% slope will accommodate up to 10.74 CFS. The
proposed culvert is sloped at3.34Yo, and will accommodate more than 10.74 CFS. Therefore the proposed
culvert's capacity is more than 35X the 100-year peak discharge of the Basin.
Please let us know if you have any questions on this.
Jon Fredericks
W EST
û.ÃilÞ FLARNT!û|G li tFVE[.oFmEñT SERvltcEs
345 Colorado Ave. #106
'Carbondale, CO 8l-623
97,O.379.4155
LANDWESTcolorado.com
From: Glenn Ha rtma nn <gha rtmann@ga rfield-county.com>
Sent: Thursday, March 10,202210:51 AM
To: JON FREDERICKS <jon@landwestcolorado.com>
Subject: FW: IExternal] Spring Valley Ranch PUD Grading Permit
Hi Jon: Here are Chris Hale's comments
As he did not provide a number for the cost estimate, please have your engineer generate an estimate for the
reclamation of the new road work. As we discussed we would anticipate it being less that
You have previously provided a copyof the State permit, and Chris just emailed me that he received it, so we are
all set on that comment.
Please address the culvert issue, an email or supplemental memo from your engineer should be acceptable.
Thanks in advance for your assistance with his topics. Glenn.
Glenn Hartmann
Principal Planner
97O-945-L377 xL57O
LAND
G ha rtma n n @ga rfield-cou ntv.co m
From: Chris@mountaincross-enß.com {hris@mou ntaincross-eng.com >
Sent: Thursday, March LO,20221-0:42 AM
To: Glenn Hartmann >
Subject: RE: lExternal] Spring Valley Ranch PUD Grading Permit
Glenn
I have reviewed the grading permit application for Spring Valley Ranch PUD. I have the following comments:
Reclamation cost estimate should include some excavation and embankment efforts to restore grades to
existing.
Area to be disturbed is greater than an acre and a CDPHE discharge permit will be necessary.
A culvert is proposed to ross the road. Design calculations to support the culvert size should be provided.
Feel free to call or email any questions or comments
Sincerely,
Mountain Cross,
Engineering, lnc.
Chris Hale, P.E.
826112 Grandi,Avenue
Glenwood Spriings, CO 81601
Ph: 970.945.5544
Fx: 970.945,.5558,
From: Glenn Hartmann >
Sent: Friday, February L8,2022 2:13 PM
To: Chris@ mountaincross-eng.com
Subject: Spring Valley Ranch PUD Grading Permit
Hi Chris: Per our phone conversation, l've attached the Grading Permit submitted by Spring Valley Ranch for initial
construction of their driveway/roadway to serve the PUD. The attachments to this email include the application,
driveway permit, past engineering approvals for the roadway, current engineering work by RFE, and an explanation
emailfrom Jon Fredericks. We are stillwaiting on a copy of their Stormwater Management Permit with CDPHE and their
revegetation/reclamation security and agreements. So while the Application hasn't been formally accepted as
complete, we would appreciate getting in line for your review. The Application will also be referred to Steve Anthony,
Vegetation Manager. Please call if we need to clarify any topics associated with the proposed grading permit. An overall
PUD Amendment Application and the Final Plat Submittals for Phase ll will also be referred to you in the future. Thanks
very much for your review and comments. Glenn.
Glenn Hartmann
Principal Planner
970-945'L377 x157O
Gha rtmann @ga rfield-countv.com
2
14"2 ûnsite Ðrain;l¡3e Elasi¡rs
The 15 onsite drainage basins were delineated using the proposed finished grade, existing grade, the
proposed Phase 2 roadway system, Pond A, and the proposed culvert system to drain to POC-A. The
Phase 2 basins are shown in Figure 5 below:
¡.- -:::r-DRAINAG¡ 5U8-BASIN DELINEAÌION
[.'igurc 5; I]l¡asc 2 d]¡rsite []¡'¡inagc [t:rsirr l)clinca{ir¡n
Spring Valley Phase 2
Final Plat Engineering Report
9
Calculation of 10O-year peak flows for all 15 basins were completed using the Soil Conservation Service
TR55 tool and the Autodesk Hydraflow Hydrographs program. Table 3 below summarizes the factors
affecting peak flows for each individual Phase 2 basin.
Basin lD
DrainageArea
(ecl
TRSSTimeof
Concentration (minf
SIS Curve
Humber
Iimeto Peak
lhrs|
Peak
Discharge {cfsf
1 5.92 103.5 6l 13.43 o.315
z 23.16 6?53 L3.7 0.259
3 13.¿18 94.8 54 14.13 0.186
i 11.5?1û.1 63 12.13 2.4
5 31.63 45.3 64 12.43 4.336
6 15.56 42.1 78 12.33 9.535
7 6.69 23.3 78 12.13 6.269
I 6.16 24 78 LZ.L7 5.?¿14
9 9.6 ¡!0.3 78 12.3 6.218
10 0.83 14.5 7Z 12.07 0.596
11 10.49 18.6 78 12.1 10.74
LZ 12.01 ?.4.t 78 12.17 10.22
13 10.18 30.4 78 12.23 7.52
14 6.49 3U.9 78 LZ.Z3 4.794
L5 8.69 13.4 56 1'?..23 0.307
'l'ablc -1: !(l(l-r'eirr f'cali Flow Calculalions for fl:¡sins I-I5
3.3 Feak Ðischarge {lalculations
Peak flows were calculated for the 10O-year storm event in both the undeveloped and developed
conditions for Phase 2 by use of the Soil Conservation Service (SCS) Runoff Curve Number method,
through use of the TR55 program and the Autodesk Hydraflow Hydrographs program. Rainfall intensities
were derived from the NOAA Atlas 14 Point Precipitation Frequency Estimates for the location of the
site, these are included in Appendix B. Curve numbers (CN) were calculated as a weighted average, by
area, of SCS curve numbers in each basin dependent on surface conditions. Times of concentration were
calculated by use of TR55, then input to Hydraflow to calculate time to peak, peak flow rate, and total
storm volume among other metrics. TR55 time of concentration calculations and hydrograph reports fcrr
all Basins 1-15 are included in Appendix C.
Spring Valley Phase 2
Final Plat Engineering Report
10
3.4 Hydrology and Hydraulics
Peak Flows were calculated for the 1O0-year storm event. Rainfall intensities were derived from the
NOAA Atlas 14 Point Precipitation Frequency Estimates for the location of the site. Curve Numbers
(CN) were calculated for each of the 15 onsite basins as a weighted average, by area, of regions of
different surface conditions. CN is a measure of how easily water flows over the surface of a given
material. The higher the CN, the more easily water flows over that surface. The curve number values used
to calculate the composite (weighted average) CN's used in calculation of time of concentration, and then
peak flow rate, aÍe provided in Appendix D.
All onsite culverts were sized at l8-inch diameter, aside from the Lupine Trace Culvert-l and Ouray Trail
Culvert-l which were both sized at L2-inch diameter due to the small amount of stormwater that they will
convey. To demonstrate feasibiliry of I 8-inch culverts, the highest single-basin 100-year runoff flow rate
(Basin 11) was modeled at2%o grade. This depicts the maximum flow at the minimum grade, therefore
demonstrating all other culverts will convey the 100-year flow of their respective basins. Figure 6 below
shows the example calculation for Basin 11 at the flow rate of 10.74 cfs for an 18-inch culvert at2Yo
grade:
Spring Valley Phase 2
Final Plat Engineering Report
11
Culvert Report
ll^lBlft Êl9ms| ÊsoÉotr kr.À!txlós¡$ ChJ 3lxr ¡y ¡*rtü,tr¡, læ.
lsrN cuLvERT @ 2%
lnvart Elev Dn (ft)
Plpe Lenglh (ft)
Slope (70)
lnvert Elov Up {ft}
Rlse (in)
Shape
Span {¡n)
No, Barrels
n"Våluð
Culvert Tlpe
Culvort Entrancs
Coeff. K,M,c,Y,k
Emb¡nkmsnt
Tap E¡€vet¡on {{t)
Top Widlh (tf
Cröst W¡dth (ft)
7213.48
60-00
¡,00
7214,68
r8.0
Circular
r8.0
I
u.ü12
Circulâr Côncrsls
Square edge úhçadwall (C)
0.00c8, å, 0.0398, 0-67, 0.5
cslûulrllonr
Omln (cfs)
Qmex {cfs}
Tailwatff El€v {ft)
Hlghllghtrd
Otolâl (cfß)
Qplpe {cÍs}
Qovartop (cls)
Veloc ûn (fUs)
Velor Up (fU6)
HGL Dn {flf
HGL Up (ftl
Hw Elêv (ft)
Hw/D (ft)
Flow Regime
lhFldae, feb ìt ãt:¡I
= û.00
= 10.74
= (dc+D)12
= 72'14é2- 7215,û5
= 7216,t7
= 0.33
= lnlet 0ontrol
I
; 1.00
= 1,00. 0.00
= 0.86
= 2.92
= 7?20,ü0
= 50.00- 0.00
tåattÌ: J ã
l:'igurc (r: l'\lni¡rle {-'alct¡latir¡ll lìrr ln lfl-inch Cr¡lvt'r't af lt}.7,{ eli
3.5 Prclposed Faeilities
3.5"I Praposcrl Refcniion fon{l
To mitigate peak drainage from Tributary Area A, a retention pond is proposed in roughly the center of
the area. This pond, Pond A, will capture flows from the northern portion of the property above (Sub Area
A), while releasing at the historic undeveloped flow rate into the southem poftion of the property below
(Sub Area A Bypass). The full pond volune will be 9,691 .54 cubic yards (cy) or 6 acre-feet of water. The
drain culvert at the southem end of the pond is designed to release at a maximum flow rate (when full) of
33.61 ct's, lf this pipe \Mere ever to be clogged, there is a weir designed to also release at this same flow
Spring Valley Phase 2
Final Plat Engineering Report
/
12
Glenn Hartmann
From:
Sent:
To:
Subiect:
Ch ris@ mou ntai ncross-eng.com
Monday, March 14,202210:30 AM
Glenn Hartmann
RE: lExternal] Spring Valley Ranch PUD Grading Permit
Glenn:
I have reviewed the culvert submittals and have no further questions.
Sincerely,
Mountain Cross
Engineering, lnc.
Chris Hale, P.E.
826112 Grand Avenue
Glenwood Springs, CO 81601
Ph: 970.945.5544
Fx: 970.945.5558
From: JON FREDERICKS <jon@landwestcolorado.com>
Sent: Thursday, March LO,2022 2:16 PM
To: G le n n Ha rtma n n <gha rtma n n @ga rfield-cou nty.com>
Cc: Chris Hale (chris@mountaincross-eng.com) <chris@mountaincross-eng.com>; Danny Stewart (dannys@rfeng.biz)
<dannys@rfeng.biz>; Martin Van Ardenne <MVanArdenne@seligmanGroup.com>; Jody Edwards (jee@kceclaw.com)
<jee@kceclaw.com>
Subject: RE: [External] Spring Valley Ranch PUD Grading Permit
Glenn,
ln response to the question regarding the culvert calculations, I have attached some relevant pages from the Engineers
Report of the Final Plat application (Appendix Q). Here is a summary:
o The proposed culvert drains "Basin 15" from the map on page 9.
o The 100-year peak discharge for Basin L5 is O.307 CFS per the Table on page 10.
¡ The culvert report on page L2 shows that an 18" culvert at2% slope will accommodate up to 10.74 CFS. The
proposed culvert is sloped at3.34Yo, and will accommodate more than 10.74 CFS. Therefore the proposed
culvert's capacity is more than 35X the 100-year peak discharge of the Basin.
Please let us know if you have any questions on this.
Jon Fredericks
WEST
lÅtrt pLtl*¡rÈrað I Þ€rllÐÞtaËll1 tÈ[t'lÊËt
345 Colorado Ave. #106
Carbondale, CO 81623
970.379.4155
LANDWESTcolorado.com
1
LANÞ
From: Glenn Hartmann <ehartmann@garfie >
Sent: Thursday, March IO, 2022 10:51 AM
To: JON FREDERICKS <ion@landwestcolo >
Subject: FW: [Externall Spring Valley Ranch PUD Grading Permit
HiJon: Here are Chris Hale's comments.
As he did not provide a number for the cost estimate, please have your engineer generate an estimate for the
reclamation of the new road work. As we discussed we would antic¡pate it being less that
You have previously provided a copy of the State permit, and Chris just emailed me that he received it, so we are
all set on that comment.
Please address the culvert issue, an email or supplemental memo from your engineer should be acceptable.
Thanks in advance for yonr assistance with his topics. Glenn
Glenn Hartmann
Principal Planner
97O-945-L377 xl570
G hartmann @sa rfield-countv.com
From: Chris(ômountaincross-enR.com <Chris@mountaincr >
Sent: Thursday, March tO,202210:42 AM
To: G lenn Ha rtma n n <gha rtma n n @ga rfie ld-co u ntv.com >
Subject: RE: [External] Spring Valley Ranch PUD Grading Permit
Glenn
I have reviewed the grading permit application for Spring Valley Ranch PUD. I have the following comments:
Reclamation cost estimate should include some excavation and embankment efforts to restore grades to
existing.
Area to be disturbed is greater than an acre and a CDPHE discharge permit will be necessary.
A culvert is proposed to cross the road. Design calculations to support the culvert size should be provided.
Feel free to call or email any questions or comments.
Sincerely,
Mountain Cross
Engineering, lnc.
Chris Hale, P.E.
826112 Grand Avenue
Glenwood Springs, CO 81601
Ph: 970.945.5544
Fx: 970.945.5558
From: Glenn Hartmann <ghartmann@garfie >
Sent: Friday, February !8,2022 2:13 PM
To : Chris(ômountai ncross-eng.com
2
Subject: Spring Valley Ranch PUD Grading Permit
Hi Chris: Per our phone conversation, l've attached the Grading Permit submitted by Spring Valley Ranch for initial
construction of their driveway/roadway to serve the PUD. The attachments to this email include the application,
driveway permit, past engineering approvals for the roadway, current engineering work by RFE, and an explanat¡on
emailfrom Jon Fredericks. We are stillwaiting on a copy of their Stormwater Management Permit with CDPHE and their
revegetation/reclamation security and agreements. So while the Application hasn't been formally accepted as
complete, we would appreciate getting in line for your review. The Application will also be referred to Steve Anthony,
Vegetation Manager. Please call if we need to clarify any topics associated with the proposed grading permit. An overall
PUD Amendment Application and the Final Plat Submittals for Phase ll will also be referred to you in the future. Thanks
very much for your review and comments. Glenn.
Glenn Hartmann
Principal Planner
97O-945-L377 xL57O
G ha rtma nn @ga rfield-co u ntv.com
3
Glenn Hartmann
From:
Sent:
To:
Subject:
Chris@ mountaincross-eng.com
Monday, March 14,2022 10:37 AM
Glenn Hartmann
RE: lExternal] Spring Valley Ranch PUD Grading Permit
Glenn
I have reviewed the revised estimate for security. Your question on a contingency is a good one. No typical amount ¡s
standard. Rule of thumbs abound. So if it's a preliminary estimate for budgeting2i% to 2O%. lf you have a bid from an
approved set of plans, you might add tO% to budget for any change orders. Unless Garfield County has a policy or
standard practice in place, I don't remember including a designated percentage contingency for security. But it's not a
bad idea. 10% would seem reasonable to adjust for inflation since, if necessary, the security will be used a few years
from now.
Sincerely,
Mountain Cross
EngÍneering, lnc.
Chris Hale, P.E.
82611t2 Grand Avenue
Glenwood Springs, CO 81601
Ph: 970.945.5544
Fx: 970.945.5558
From: JON FREDERICKS <jon@ la ndwestcolorado.com>
Sent: Thursday, March 70,2022 2:56 PM
To: G lenn Hartmann <gha rtma nn @garfield-county.com>
Cc: Chris Hale (chris@mountaincross-eng.com) <chris@mountaincross-eng.com>; Danny Stewart (dannys@rfeng.biz)
<dannys@rfeng.biz>; Martin Van Ardenne <MVanArdenne@seligmanGroup.com>; Jody Edwards (jee@kceclaw.com)
<jee@kceclaw.com>
Subject: RE: [External] Spring Valley Ranch PUD Grading Permit
Glenn,
Attached is the revised Reclamation Estimate.
o lncreased seeding to 53600 per Steve Anthony's request
o Added S10,000 unclassified excavation
o Added S10,000 embankment
The new total is 548/42.70. Please advise if this is acceptable.
Thank you-
Jon F¡,edericks
w Ësï
L¡ùè tla*tra¡lð I bËiJ€lttFi.lË|lT tlFulÊ{1.
1
LAHD
345 Colorado Ave. #l-06
Carbondale, CO 81623
970.379.4155
LANDWESTcolorado.com
FTom: JON FREDERICKS
Sent: Thursday, March LO,2022 2:16 PM
To: Glenn Hartmann <gha rtma nn@garfield-countv.com>
Cc: Chris Hale (chris@mountaincross-eng.com)<chris@mountaincross-eng.com>; Danny Stewart (dannvs@rfene.biz)
<dAruE@-ffglg.bl¿>; Martin Van Ardenne <MVanArdenne@selismanGroup.com>; Jody Edwards (iee@kceclaw.com)
<iee@-kçeç.lêru.cqm>
Subject: RE: [External] Spring Valley Ranch PUD Grading Permit
Glenn,
ln response to the question regarding the culvert calculations, I have attached some relevant pages from the Engineers
Report of the Final Plat application (Appendix Q). Here is a summary:
o The proposed culvert drains "Basin 15" from the map on page 9.¡ The 100-year peak discharge for Basin 15 is 0.307 CFS per the Table on page 10.o The culvert report on page 12 shows that an 18" culvert at2% slope will accommodate up to L0.74 CFS. The
proposed culvert is sloped at3.34%o, and will accommodate more than 1-0.74 CFS. Therefore the proposåd
culvert's capacity is more than 35X the 100-year peak discharge of the Basin.
Please let us know if you have any questions on this
Jon Fredericks
WEST
L¡liG tL¿rß¡f*ô I ÞÊfèLù*,iÉl|î tÈnftcÉ3
345 Colorado Ave. #106
Carbondale, CO 81623
970.379.4155
LANDWESTcolorado.com
From: Glenn Hartmann >
Sent: Thursday, March 10,202210:51- AM
To: JON FREDERICKS <jon@landwestcolo >
Subject: FW: [External] Spring Valley Ranch PUD Grading Permit
HiJon: Here are Chris Hale's comments
As he did not provide a number for the cost estimate, please have your engineer generate an estimate for the
reclamation of the new road work. As we discussed we would anticipate it being less that
You have previously provided a copy of the State permit, and Chris just emailed me that he received it, so we are
all set on that comment.
Please address the culvert issue, an email or supplemental memo from your engineer should be acceptable.
Thanks in advance for your assistance with his topícs, Glenn.
Glenn Hartmann
Principal Planner
2
LAND