HomeMy WebLinkAboutResponse to Correction LetterDHMLANDSCAPE ARCHITECTURE
ECOLOGICAL PLANNING
UP ES GN
DESIGN LAND PANNING
August 10th, 2026
John Plano
Building Official
Garfield County Community Development
108 Eighth Street, Suite 401
Glenwood Springs, Colorado 81601
(970) 945-8212
John,
Below are the Colorado Extreme project team's responses to the second Long Span Structure (LSS)
Corrections Letter "Corrections to address prior to issuing a building permit" received on 7.22.26. We
believe that these satisfy the requirements to deem the application complete.
In addition to this response memorandum, we have attached an appendix containing the revised plans. All
plan modifications have been clouded.
Please let us know if you have any questions as you review.
Corrections to address prior to issuing a building_paermit.
1. The east exit needs to provide a path to the parking lot otherwise called the "Safe Dispersal Area".
The berms and drainage areas obstruct the exit discharge. (IBC 1028.5)
Response: No obstructions exist at the east exit discharge. The plans have been revised with
additional spot elevations and cross sections to demonstrate the absence of obstructions and the
accessible route to the safe dispersal area / parking lot has been identified. See Appendix.
2. The proposed drainage basins require a Civil Engineer's Stamp on all the pages and storm drainage
report.
Response: As requested, a civil engineer's stamp has been added to all narrative and exhibit pages
of the storm drainage report. See Appendix.
Sincerely,
DHM Design
Jason Jaynes, Managing Principal
970.366.16371 jjaynes@dhmdesign.com
DENVER CARBONDALE DURANGO 225 Main St Unit 201, Carbondale, CO 81623 1970.963.6520 DHMDESIGN.COM
Appendix Table of Contents
Appendix 1: Site Plans
Appendix 2: Drainage Report
Appendix 1: Site Plans
Appendix 2: Drainage Report
DRAINAGE REPORT
REVISED DRAINAGE BASIN 3
FOR
COLORADO EXTREME CARBONDALE
Owner:
Blue Mind, LLC
5490 Upper Cattle Creek Road
Carbondale, CO 81623
Prepared by:
High Country Engineering, Inc.
1517 Blake Avenue, Suite 101
Glenwood Springs, CO 81601
(970)945-8676
For and on Behalf of
High Country Engineering, Inc.
HCE Project No. 2251018.00
June 19, 2026
Revised: August 7, 2026
TABLE OF CONTENTS
SECTION PAGE
I. PURPOSE..........................................................................................................................3
II. LOCATION.......................................................................................................................3
III. PRE -DEVELOPED CONDITIONS............................................................3
IV. EXISTING CONDITIONS.............................................................................................. 4
V. PROPOSED CONDITIONS............................................................................................ 4
VI. SUMMARY....................................................................................................................... 5
VII. RECOMMENDATIONS.........................................................................5
VIII. REFERENCES..................................................................................................................5
APPENDIX A: Hydrologic calculations
APPENDIX B: Storm water storage
APPENDIX C: Exhibits
2
I.
II.
PURPOSE
The purpose of this report is to modify the Drainage Report for Colorado Extreme Carbondale. This report
intended to support Phase 1 of the project, This report identifies the needed storm drainage infrastructure to
accommodate planned future improvements within Drainage Basin 3 of the Colorado Extreme Carbondale
Hockey facility.
In the future, the applicant intends to reexamine the analysis of Drainage Basins 1 and 2 separately, as part
future development phases of the project.
LOCATION
The Colorado Extreme Carbondale Hockey facility is located at 2340 County Road 100 (Catherine Store
Road), in unincorporated Garfield County. Drainage Basin 3 is situated within the westerly region of the
site, as shown on the attached Vicinity Map
PRE -DEVELOPED CONDITIONS
The pre -developed conditions of the Drainage Basin 3 are consistent with the surrounding undeveloped
areas in the region. Native vegetation included: grasses, shrubs, oak brush, sage brush, juniper and pinyon.
According to the Soil Survey of Aspen - Gypsum Area, Colorado, there are three (3) soil types present
within Drainage Basin, as shown in the attached Soil Map. The mapped soil types are as follows:
■ Grotte gravelly loam, 25 to 65 percent slopes. Deep and well drained. Permeability is
moderately slow. Runoff is rapid. Hydrologic group: B.
■ Gypsum land-Gypsiorthids complex, 12 to 65 percent slopes. Shallow to moderately deep,
and well drained. Permeability is moderate. Runoff is very rapid. Hydrologic group: B.
Yamo loam, 12 to 25 percent slopes. Deep and well drained. Permeability is moderate.
Runoff is rapid. Hydrologic group: B.
Calculated peak flows for the pre -developed basins are tabulated in Table 1 below.
Table 1. Pre -developed Drainage Basin Characteristics
DRAINAGE AREA Impervious Te 25-YR 100-YR
(%) C5 PEAK PEAK
BASIN (acre)
(min.) FLOW (cfs) FLOW (efs)
HI-3 13.62 5 0.03 1 18.5 9.5 19.9 t�ADO '_C
S�ONAL `GN
IV. EXISTING CONDITIONS
The Drainage Basin 3 site is currently developed. Existing improvements include: fences, a building, gravel
driving surfaces, utilities and irrigation facilities.
Calculated peak flows for the existing basins are tabulated in Table 2 below.
Table 2. Existing Drainage Basin Characteristics
Te
25-YR
100-YR
DRAINAGE
AREA
Impervious
C5
PEAK
PEAK
BASIN
(acre)
N
(min.)
FLOW (cfs)
FLOW (cfs)
EX-3
13.62
14
0.11
18.1
11.6
21.7
There are currently no formalized storm drainage structures present within Drainage Basin 3. Storm water runoff
from the site is intercepted by the existing roadside ditch system alongside County Road 100 and the Rio Grande
Trail. Storm water runoff currently leads to the Roading Fork River.
V. PROPOSED CONDITIONS
The applicant intends to construct a Long Span Structure (LSS), and associated gravel parking surfaces within
Drainage Basin 3. Those proposed improvements are identified in the approved Colorado Extreme Land Use
Permit.
Calculated peak flows for the proposed basins are tabulated in Table 3 below.
Table 3. Proposed Drainage Basin Characteristics
Te
25-YR
100-YR
DRAINAGE
AREA
Impervious
C5
PEAK
PEAK
BASIN
(acre)
N
(min.)
FLOW (cfs)
FLOW (cfs)
PR-3
13.62
14
0.11
18.1
11.6
21.7
The applicant intends to construct new storm water detention facilities to mitigate increased storm water
runoff. The proposed detention facilities are to detain both the 2-year and the 25-year rainfall events, while
passing the 100-year event, in accordance with Garfield County Land Development regulations, as shown on
as shown on Exhibits 8 and 9.
The required 25-year storage volume for Drainage Basin 3 has been calculated to be 0.217 acre—feet, as shown
in Appendix B.
The proposed 25-year storage volume is to be accommodated within three (3) linkKanWjdetention
basins, having a 25-year storage volume of 0.17 acre-feet, The combined stora9r•4to I in
Table 4 below. °r'• s�,
.o
NAV . EaG�
4
VI.
Tahle d_ Prnnnsed 25-Year Runoff Detention Storaec Volumes
STORAGE
STORAGE
BASIN
BASIN
VOLUME
VOLUME
NAME
LOCATION
(Cubic Feet)
(Acre - Feet)
North East
Upper
811
0.019
Center
Middle
8,025
0.184
West
Lower
614
0.014
Total
9,450
0.217
SUMMARY
The applicant intends to construct a Long Span Structure (LSS) to accommodate a new Hockey Rink. The
applicant also intends to construct new gravel parking surfaces within Drainage Basin 3, as approved under
the Colorado Extreme Special Use Permit for the site.
VII. RECOMMENDATIONS
In order to mitigate the anticipated increased storm water runoff, the applicant proposes to construct three (3)
linked, cascading, shallow storm water detention basins, in accordance with applicable Garfield County Land
Use standards. The combined detention basin are to have adequate storage capacity to accommodate both the
2-year and the 25-year runoff volumes. The proposed detention basins are to be constructed with a discharge
outlet weir to allow the 100-year runoff flow rate to safely pass to the north. The proposed detention basins
are also intended provide a means of enhancement the quality of the captured storm water, by providing
opportunities for water -borne sediments and other debris to settle and remain within the depressed basins.
Due to their close proximity to the proposed Long Span Structure (LSS), the bottoms of the three (3) Detention
Basins should be lined with imperious membranes, to mitigate seepage with may affect the foundation of the
proposed LLS.
VIII. REFERENCES
1. Soil Surveyof fAspen - Gypsum Area, Colorado, U.S. Department of Agriculture, Soil Conservation
Service, May 1992
2. NOAA Atlas 14, Volume 8, Version 2, Point Precipitation Frequency Estimates, National Oceanic and
Atmospheric Administration: 2022
3. Estimation of Runoff and Storage Volumes for Use with Full Spectrum Detention, Urban Drainage and
Flood Control District: Revised January 5.2017
DO L /C
4. Urban Storm Drainage Criteria Manual Volume 1, Mile High Flood District:
5. Drainage Report for Colorado Extreme Carbondale, High Country Engineerii .•
s`S�Onrei EaG�
APPENDIX A
Hydrologic Calculations
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APPENDIX B
Storm water storage
Storm Water Runoff Storage V011rrne
According to the Garfield Eagle County Land Use and Development Code Section 7- 204. C . 3 . a.:
"Detention facilities shall ensure the post -development peak discharge rate does not exceed the pre -
development peak discharge rate for the 2-year and 25-year return frequency, 24-hour duration storm. In
determining Runoff rates, the entire area contributing Runoff shall be considered, including any existing off -
site contribution."
Determination Method
The required volume of the storage basin has been calculated using storage volume Equation (17) as defined in
Estimation of Runoff and Storage Volumes for Use with Pull Spectrum Detention, as follows:
Vstorage 25 yr (ac-ft) =Pi A [(0.083 1'-"8) A%+(0.056 I1.290 + 0.021 10.290) B%+(0.048 11.382 + 0.026 11312) CD%1
Where:
Vstorage_#yr is the required storage volume (acre-feet)
P1 is the one -hour rainfall depth corresponding to the 25-year return period: 0.953 inch
A is the watershed area of proposed drainage Basin PR-3 = 13.62 acre
I is the percentage of proposed drainage basin PR-3 imperviousness (expressed as a decimal): 0.1451
A% is the percent of hydraulic soil group A (expressed as a decimal): 0.0
B% is the percent of hydraulic soil group B (expressed as a decimal): 1.0
CD% is the percent of hydraulic soil groups C and D (expressed as a decimal): 0.0
Required 25-year Storage Volume
Based on Equation (17) above:
Basin PR-3 Vstorage25 yr = 0.217 acre-feet or 9,448 cubic -feet
Proposed 25-year Storage Volume
Based upon the proposed drainage map include in the appendix:
V25 prop. = 0.217 acre-feet or 9,450 cubic -feet
Conclusion
Since the proposed 25-year storage volume equals the required 25-year storage volume, adequate storage capacity
for the 25-year event is to be provided.
Runoff in excess of the 25-year event is to escape the proposed storm water storage facilities in a northerly
direction, via a proposed overflow weir, adjacent to the County Road 100 Right-of-way.
APPENDIX C
Exhibits
DRAINAGE
BASIN 3
5. ---
000
aN00 LIC,
O
NOT FOR 93
CONSTRUCTION
ASS/. .....
COLORADO EXTREME
HIGH COUNTRY ENGINEERING, INC.
GARFIELD COUNTY, COLO.
1517 BLAKE AVENUE, STE 101,
2340 COUNTY ROAD 100
GLENWOOD SPRINGS, CO 81601
PHONE (970) 945-8676 FAX (970) 9452555
DRAINAGE BASIN 3
WWW.HCENG.COM
VICINITY MAP
HIGH COUNTRY ENCIN=ERING, INC.I
DRAWN BY: SCALE: JJ
HCE 1 - 1 ,000'
CHECKED BY: PROJECT NO
HCE 2251018.00
DATE. PAGE:
8-7.26 1
FILE. EX-01.DWG
Counhl Rid 100
�l
RAINAG E
III
54: GROTTE
GRAVELLY LOAM, 25 TO
65 PERCENT SLOPES
HYDROLOGIC
GROUP: B
Ll
cF
55: GYPSUM
LAND-GYPSIORTHIDS, 12
TO 65 PERCENT SLOPES
OaP00
per.
0j'•�S�
HYDROLOGIC
GROUP: B
NOT FOR
93
CONSTRUCTION
po,-
116: YAMO LOAM,
12 TO 25 PERCENT
SLOPES
�S' '•••'' G��
S�01VAL
HYDROLOGIC
GROUP: B
iFOR � L OF
HIGH COUNTRY ENGINEERING, INC.
HIGH COUNTRY ENGINEERING, INC. GARFIELD COUNTY,COLO. HCE I"=400'
CHECKED BY: PROJECT NO:
1517 BLAKE AVENUE, STE 101 , 2340 COUNTY ROAD 100 HCE 2251018.00
GLENWOOD SPRINGS, CO 81601 DATE PAGE:
PHONE (970) 94S-8676 FAX (970) 945.2555 DRAINAGE BASIN 3 a7,28 2
WWW.HCENG.COM SOIL MAP
E' EX-02.DWG
NOAAAtlas 14, Volume 8, Version 2
-. Location name. Carbondale, Colorado, USA`
Latitude: 39.397', Longitude:-107.2175'
Elevation: 6195 ft"
• source: ESRI Maps
" source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
Santa Perica. Deborah Martin, Sandra PavlDvic, Ishani Roy, Michael St. Laurent• Cad Trypaluk, Dale
Unruh, Michael Yekle, Geotfery Bonnin
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF gLaphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average
recurrence_
interval (years)
100
200
500
1000
llurallon���
10
25_jr75D
0. 660
0.10E
0.241
0.305
0.386
0.444 0.497
0.648
0.608
0.648
5-min
(0.086.0.139)
(0.127,0207)
(0,191-0.312
(0239.0.397)
(0287-0.515)
(0.324.0.1 5 (0.350-0.700
(0.3W-0.797)
(0392-0.917}
(0.410-1.01
0.565
034
0�94
10-min
O.1250.203
0.186-0 302
.279-0 0.457
00-0 .35.581
,421-0.7SS
0.474.0.888 0.512 1 02
0.5301-1.17
0.574
0
21
8
8
15 trlin
(0.220389)
0.340.0,50.27.08
07
S1-09
.8.625125
0.0
90
.700.1.84
0.732.1.800,153-024B
30-min
0205-0333
(04.0.479
29
0.430.0.705
0.5-410.884
0.6321913
0.706--132 0.758-18 .52
.790A.71)
0.837.1.96
0.870.2.14
I
60-min
(0273.0 443)
(0.364-0 593)I
(0.504.0.82
(0.6101 01)
(0.719127)
0.78 -18.47 (0.W.1.68)
(0.874-10.89
0420 2.15)
0.954 2.94
2-hr
(0.3440 y16)0,439
0
(0 585 0 938
0.693 1512)
0.799 1.39
0 878-9.80 10.932-1.82
.966 2A4
Lpi 2531
1-052 51
3-h r
0.407-083
2698);
0 4940 774
0.629 0.992
0.732 1617
.83 09.43
.907 1.63
0.959 3.84
.994-2.07
1.04 235
1.08 2.56
6-hr
0.663
0.542-0826
0.616-0.941
O.D�513
0.833.1.30
0.941-1.58)
1.021579
(1.09.2.01) 1
1.14-2.31
1.222?68
118-2.95
1.29
1.53
1.72
1.92
2.12
Z40
2.63
12-hr
0.829
(0.686-1.02)
0.941
(0.777-1,18)
1.13
(0.929.1A0) 1
1.21-1.98)
1 (1.32-2.28)
1.42-2.60
1.W2.98)
1.63.3.49)
1.73.3.88
24-hr
(0837.1.21
0.95B•5.39
1.18 1.70
1.34-61Z98
1.552.48
1.Tt 2.85
1.8d 3630
1.W-3.80)
2.14•449
(2.28.5.Oi
2-day
1 001 B2
531.63
140 200
1.612.32
1.97 2192
2.06 3.36
23 3 90)
2.38 4 50
2.61.5.33
2: 9 5 95
..3
12 1256
1.285178
1.3-day
156.2..19
79. 1.2.54
,06.3.17
2.27 3.65(2,154.211)11
.604.84
2.84-5.71
3.03.6
4�ay
1.2243881.68
234
1.92-271
2.21.336
2.42.3.84)
2.80 4A2)
7 5.5.08 1
(2.99 5894
3.17.6.50
7-day 71099) 1.8.2 25) ! 1-97 269 2.23.3.07 2 S2J 74 2,74 424) 2.91-4.84 .065.50) (3.29 6.38 34 8.7..05
10-day 1.94 2.18 2.55 2,89 3.3fi 3.73 4.10
1.69.225 1.89.2.52 222.2.98 2.49.3.38 .794.08 3,01.4.60 195.21
2.61 2-90 3.38 3.77 4.32 4.75 5.19 Pp ��'
20-day
(230.298) I (Z56.3.31) 2.96-3.87 329.4.34 3.625.16 (3.88-577 4.07.6.48 V FjL
�� ' ��
30-day 2.61-3.58 3. 23 99) 3.61 41351 f4.00 6621 CAA 5.70 6�19 5) 0�• •,
N'4
45-day 3 47-4 86�386 4 , e 58 8 4.96 6236 (5.76.8.27 (5 98 9. 93
60-day 4.04.6.01) 14.52 5.62 526.6.59 5.83 7..38 6. 7 _
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (POS) �s • • • .....
Numbers n parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability 1 `s/0 AL �N
(for a given duration and average recurrence Interval) Will be greater than the upper bound (or less than the lower boL
are net checked against probable maximum 01"Ortalion (PMP) estimates and may be higher than currently valid PM(
Please refer to NOAA Atlas 14 document for mare information I P H
HIGH COUNTRY ENGINEERING, INC.
COLORADO EXTREME DRAWN BY: SCALE:
HCE N/A
HIGH COUNTRY ENGINEERING, INC. GARFIELD COUNTY, COLO.
CHECKED BY: PROJECTNW.
1517 BLAKE AVENUE, STE 101, 2340 COUNTY ROAD 100 HCE 2251 01 8,00
r GLENW000 SPRINGS, CO B1601 DATE: PAGE.
PHONE (970) 945-8676 FAX (970) 945-2555 DRAINAGE BASIN 3 3
8-1 7-26
WWW.HCENG.COM NO.A.A. RAINFALL DEPTHS
FILE:
EX-03.DWG
NOAA Atlas 14, Volume 8, Version 2
Location name: Carbondale, Colorado, USA' `
Latitude: 39.397°, Longitude:-107.2175°
Elevation: 6195 ft-
' source: ESRI Maps
" source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
sanie Ponca, Deborah IAarrin, Sandra Pavlovic, Ishani Ray, MlcAaol St Laurent, Cad Trypaluk, Date
Unruh, Michael Yekla, Geolrory ac rnrn
NOAA, National LVealher Service. Silver Spring. Maryland
PF tabular I FF graP icaA I RkjLea r1a3s
PF tabular
PDS-based point preciplitaflon frequency estimates with 90% confidence intervals (in inchesfh5 u
;;Ion
Average
recurrence interval (years)
F
1 JL� 10
25F 5D
100 200 500 1000
5-min
1.03 106>�
LI s2.2,4�
(2293 74)J
67 7614.
13.44.6.16)
9 33
B01
a.4
.58
(4.4295
30
4.70
4,92 12,1)
10 min
t.67-2.74)
0 3 a9)
2.53 J 53
284.5.32
3.07 fi 25
4.
9.238700)
3.44.8.05
.61 8985
15 min
750 t94' 2)
{1.124181
2.23
1.71 2.83
205 3668)
12.31..4.32 I
5500
2.835.70
2.80-6.55)
2.93-7.20
0.612-0.992
0 908.4.48
(t36
.50
30 min
(04010--0 f
(0.5880958)
j0_860.941)I
1.0731677)
(1.262.26)
(1.41-264)
0.523.0311
(1.59.3.43)
1.67391
1.744T7)
9532�
60 min
0.273.0 443
0.364 0 593
(0.504 0.8?7);
(0 6t0 1.011
0.
f0.787-g.47)
(0.840.9.68)
fOB74-�.89)
(0.920 2.15)
0.954 2.34)
o.90r
2-hr
0.172.0 273
0.219.0.340
(0292-0.466
(0.347-0.562
0.399-0 e97
(0.439-0 799
0.4ae
(0. 83.01A2
0.50B 16IS
0.5^,4-21026)
3-hr 0.167 0.203 0260 0.305 0.362 0.404 0.444 0.482 0.526 0.560
0.135-0.212 0.16d-0.257 0209-0.330 1.383 0.276.0.475 0.302-0.541 (0.319.0.613 0.331.0.688 0.347-0.781 0.360.0.651'
6-hr 0090 00 37 0.1 D2 05i 57 0.122-0.189 0 139-0 216 O.IS7.0.263 0.170 0 299 0. t81.0 340 0.10( 90.0'3N6 020.7 0.447 (0.213-0 492
12-hr 0056-0 084 (0.064 0 096) (007 D03115), (0087-0.133 0.100 0164 0.109-0 187 0.1017-0215)(0.124.0247jr {0.135.0 289) (0.1430321
0.047 0.058 i 0.067 0.080 0.0 11 0.102 0.114 0-130 OA 43
0.041
24-hr (0.034-0.050 0.039.0.058� 0.04E-0.0711 (O.C55A.082 0.064.0.103 (0.071.0.118) (0.076-0.13T O.Ob1.0.158) (0.089-0.186 (0-095-0208
2 day 0: 20.0 029 0023-0033 (00 29.0 041) 0033 U 04800
0: 38.0.060 (0.042 0 070) (0.046-0 061 0 049 0 093 0054-0BS 10�1(0.058-0123
00024)
3-day 000yp 021 0 00 (0.02 -0.030)k0.024-0.035 0.028.0.044 0031---0.050 (0.034-0.058 0038 O9 0039.0 0791 0-042.0.088
17-7
0
4-day 00120 017 0.0014--0 020) {0.017-0 O24)I (0.020-0 028, (0.023.0.03d (0.025-0.04010.027-0.048 0.028 0 052 (0.03 U 061)] (0.033 .068
0.013 0.015 0018 0.020 0.022 0.024 0.027 0.030
-dayn0.010 0.011
(OT008-0_011)1(0.009-0.013) (0.011-0.015) 0.013-0.018j .014.0.022 (0.016.0.025 10.017.0.028) (0.018.0.032) (0.019.0.037) (0.020.0.041
n1(0.9
10�ay 0.008 0.009 0.010 0.012 9.o1a 0,015 0.017
0.007.0.010 0.009.0.012 0.01o•0.014 0.011-0.016) 0.012.0.019 0 013-0 021 0.
(0.007-0.009
20 day J 0.00d�006 0.005 0006 0.00D -.006 o.aos oAo9 o.eai o010 (o.00D&0012} 0.008-0013 0. V- q ND 0 I�'c�
30�ay 0,004 IF 0.0047F 0.005 I 0.006 F 0.007 f 0.007 0-008 0) (0 t�•'� Oi
0.0030.004 0.0040.005 0.0050.0�08 0.005.0007 0.006.0.00 II 6 _
OS•
45 day (0.003.0.OD4) (0.D03.0.004) 10.004-0.005)i (0.004-0.00b 005 00 ) . .007 10. 0. 93
6D�ay 0.003 0.003 0,004 0.004 0.00
(0.002.0.003 0.01Xi-0.003� 0.0030.004I 0.004-0.005 0.004-0 ^ �: �QX.c�• 7/,?(p,••�<(/
1 Precipitation frequency (PF) eslimates in this table are based on frequency analysis of partial duration series (PDS). `s • • . , , • • . • G��
Nurnbers In parenthesis are PF estimates at Inver and upper bounds or the 90% confidence interval. The pro5ab11ity lh `S�ONAL EN
given duration and average recurrence interval) wit be greater than the upper bound (or less than the lower bound)
chocked against probable maximum precipitation (PMPI estimates and may be higher than currently valid PI11P values.
Please refer to NOAAAOas 14 document for more inform atton.
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HIGH COUNTRY ENGINEERING, INC. GARFIELD COUNTY, COLO.
CHECKED 9Y: PROJECT NO:
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VVWW.HCENG.COM N O.A.A. RAINFALL INTENSITY
FILE*
EX-04.owG
DurationRainfall Intensity -• Carbondale •
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HIGH COUNTRY ENGINEERING, IN
COLORADO EXTREME DRAWN BY: SCALE:
HIGH COUNTRY ENGINEERING, INC. GARFIELD COUNTY. COLO. HCE N/A
CHECKED BY: PROJECT NO:
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Runoff Chapter
TABLE 6-3. RECOMMENDED IMPERVIOUSNESS BY SURFACE TYPES
IMPERVIOUSNESSSURFACE
TYPES
Roadways and Paved Streets _ _ _
_ 95% _
Concrete Driveways and Walks
98%
Roofs
95%
No Traffic (Pedestrian Use)
40%
Gravel Low -traffic Areas (Maintenance Paths and Substations)
60%
High -traffic Areas (Roadways and Parking)
80%
Disturbed Soil (Including Lawns, Managed/Active Turf, Landscaped Areas with
o
20 /o
Water -Wise Vegetation, and Uncompacted Gravel/Mulch Planting Beds)_
Undisturbed or Decompacted Soil (Native Grasses and Open Space Areas)
5%
Landscape Applications (without Subgrade Drainage Layer)
25% - 45%
Artificial Turfs' --
Sport Fields (with Underdrain Pipe System) _
60% - 80%
Water Surfaces (Lakes/Reservoirs/Irrigation Ponds)
100%
Grass Cover (Varies with Panel Orientation Relative to
100/6- 45%
Ground Contours)
Solar Fields' — — — --- -
Gravel Cover (Varies with Panel Orientation Relative to
-
50% - 75%
Ground Contours)
Historic Flow Analysts, Greenbelts, Agricultural - _ _ _
5
Newly Graded Areas
65 %
Retention Ponds & Constructed Wetland Ponds 100%
Rooftop Systems - Blue Roofs
95%
Rooftop Systems - Green Roofs (extensive)
65%
Stormwater Rooftop Systems - Green Roofs (intensive) _ _ _
50%
Control Permeable Pavement - CGP/PGP/RGP
55%
Measures' Permeable Pavement - PICP
45%
Extended Detention Basins 25%
Recoiving Pervious Areas (incl. Grass Buffers & Grass Swales) _ 20%
Bioretention & Sand Filters _ _ _ 10%
I Consult with the manufacturer to get a recommenced value
t 4ssurxsld ratbor paMls to ahles See MHFD'a teehni�l mamorandumregardin¢Drterr,inptan o/Sof*rpnnel Feld puno7 Coe(ric,rrls orM lmprrvia.sn<ss
Value fa addilbnal information on procadutas tar determining penent ,rip orswusness based on par*! w,dIh. panel saocmt, and panty onontat,os lot al,ve tc
pound eontaurs aid hom to mfloet*that impInnous areas such as mods and pads that may be part ora solar hold and ayoulswithwid,r intro Pa l,P.m9
i See MHFD's technical memo rendam regarding Evaluation o/Percent Imperviousnem /or.tormwater Control Meeaurea for background mformatior,
NOT FOR
CONSTRUCTION
M
93 `�
�S/Olvnt ENG�
HIGH COUNTRY ENGINEERING, INC.
cEXTREME
DRAW
SCALE:
HIGH COUNTRY ENGINEERING, INC.
GARMELD MELD CO COUNTY. COLO.
HCE
N / A
CHECKED BY
ROJECT O:
e0112
141NVERN PHONE1(303)
ea.�4O COUNTY ROAD 100
HCE
225101$.00
92r0444 FAX(303) 9225054D.CO
1517 BLAKE AVENUE. STE 10 t. GLENWOOD 5PRINGS. C091601
11GW.� DRAINAGE BASIN 3
DATE:
8/7/26
PAGE
6
PHONE(970) 945e676 FAX(970) 9452555
IMPERVIOUS PERCENTAGES
W W W..CENo.coM
FILE:
EX-06
Runoff
Chapter
TABLE 6-7. RUNOFF COEFFICIENTS, C, NRCS HSG B
TOTALOR
•
WQE&
5-Near
_ 10-Year
25-Year
50-Year
100-Year
500-Year
2-Year
2%
0.01
0.01
007
026
034
044
0.54
5%
003
003
010
029
036
045 �
0.55
10 %
0,06
0.07
0.14
0.31
0.32
0.47
0.57
1516
009
0.11
Ole
0.34
0.41
0.50
Y 0.59
-
20%
0.13
0,15
0.22
0.37
0.44
0.52
0.61
25%
0.17
0.19
026
0.41
047
054
0.63
30%
0.20
0.23
0.30
0.44
0.50
0.57
0.65
35%
0.24
0.27
034
0.47
0.52
0.59
0.66
40%
0.29
0.32
0.38
0.50
0.55
0.61
0.68
45%
O 33
0.36
0 42
0.53
0.58
0.64
0.70
50%
0.37
0.40
0.46
0.56
0.61
0.66
0.72
55%
042
0.45
0.50
0 59
0.63
0.68
0.74
60%
0.46
0.49
0.54
0.63
0.66
0.71
0.76
65%
050
0.54
0.58
0.66
0.69
0.73
0.77
70%
0.55
0.58
0.62
0.69
0.72
0.75
0.79
75%
060
0.63
066
0.72
0.75
0.77
0.81
80%
0,64
0.67
070
0.75
0.77
0.80
- 0.63
85 %
069
0.72
071,
0.78
0.80
0.82
0-85
-
90%
0.74
0.76
0.78
0.81
0.83
0-84
0.87
95%
0.79
0.81
0.82
0.85
0.86
0.87
O.BB
100 %
0.84
0.86
0.86
O.BB
0.89
0.89
0.90
NOT FOR
CONSTRUCTION
HIGH COUNTRY ENGINEERING, INC.
HIGH COUNTRY ENGINEERING, INC.
COLORADO EXTREME
DRAW HCE
SCALE:
N / A
GARFIELD COUNTY, COLO.
CHECKED BY:
PROJECT NO:
t 4INVERNESS DRIVE EAST, STE F•120, ENGLEWOOD, CO 60112
2340 COUNTY ROAD 100
HCE
2251018.0'-
PHONE(303) 9250544 PAX(303)925as47
qu 1S17 BLAKE AVENUE. STE 101. GLENWOOO SPRINGS.0061601
DRAINAGE BASIN 3
DATE
8/7/28
PAGE
7
PHONE FAX t970) 945-2555
RUNOFF COEFFICIENTS
www. KCLRO.cOM
FILE:
EX-07
�ouNT
RIO GRANGE TRAIL � - ` 7
j - - -
17
PROPOSED
-RIP
/ PROPOSED / / CHANNEL
CASCADING-
-IP RAP i
PROPOSED — / -CHANNEL '���►�iTaF' AY I 25 - /
OVERFLOW WEIR _ J J 25 i
TO PASS THE — 25
100-YEAR FLOW �`' 2
2 25 25
25 PROPOSED LINED
25
25 UPPER BASIN
25 25 / �25—YR STORAGE
-VOL: 0.01 AC. F
G: 6256
�P PROPOSED LINED
FG:6256 LOWER BASIN
al? VOL:Y 0.0140RAGE AC, FT. . 1 PROPOSED /LINED
�
P
/J \ VIDDLE BASIN
P� P` 25—YR STORAGE
// -VOL:��-0.184 AC. FT.
Q
\,
— S� l j///i//� / //i/// /�/: Epp 0 L /c
93
7/
ANAL E ,
FOR AND ON BEHALF OF
HIGH COUNTRY ENGINEERING, INC.
COLORADO EXTREME DRAWN BY: SCALE:
HIGH COUNTRY ENGINEERING, INC. GARFIELD COUNTY, COLO. HCE =ao
CHECKED Br PROJECT NO:
1517 BLAKE AVENUE, STE 101. 234.0 COUNTYROAD 100 HCE 2251018.00
GLENWOOD SPRINGS, CO 81601 OATF: PAGE
PHONE (970) 945-8676 FAX (970) 945-2555 DRAINAGE BASIN 3 &7.26 8
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10'
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MEMBRANE
ANCHOR TRENCH
PER MANUF.
TYPICAL CROSS SECTION A -A
N.T.S.
TYPICAL CROSS SECTION B-B
N.T.S.
NOT Fo- R
CONSTRUCTION
<;OIL
IMPERVIOUS
GEO MEMBRANE
LINER
aoa�s
'ONnt rcN 0
FOR AND ON BEHALF OF
HIGH COUNTRY ENGINEERING, IN('
COLORADO EXTREME
DRAWN BY:
scALt:
N.T.S.
HIGH COUNTRY ENGINEERING, INC.
GARFIELD COUNTY, COLO.
HCE
CHECKEO BY:
PROJECT NO:
1517 BLAKE AVENUE, STE 101 ,
COUNTY ROAD 100
HCE
2251 O t 8.co
I• GLENWOOD SPRINGS, CO 81601
12340
D'TE•
PAGE:
PHONE (970) 945-8676 FAX (970) 945-2555
DRAINAGE BASIN 3
&7�6
9
W1NW.HCENG.COM
TYPICAL CROSS SECTIONS
FlLE:
EX-09. owG