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HomeMy WebLinkAbout3.2 697-16-16 Drainage ReportDrainage Report CASCADE CREEK 697-16-16 ANNEX STORAGE AREA Garfield County, Colorado Prepared for: OXY USA Inc. 760 Horizon Drive, Suite 101 Grand Junction, CO 81506 Office Phone: 970-263-3634 Prepared by: D.R. Griffin & Associates, Inc. 1414 Elk Street, Suite 202 Rock Springs, WY 82901 Office Phone: 307-362-5028 January 2, 2015 D.R. Griffin & Associates, Inc. Job #: 14623 TABLE OF CONTENTS 1) INTRODUCTION a) Background b) Project Location c) Property Description d) Previous Investigations 2) DRAINAGE SYSTEM DESCRIPTION a) Basin Descriptions b) Existing Drainage Conditions c) Offsite Drainage d) Proposed Drainage System Description e) Drainage Facility Maintenance 3) DRAINAGE ANALYSIS AND DESIGN CRITERIA a) Regulations b) Development Criteria c) Hydrologic Criteria d) Hydraulic Criteria 4) CONCLUSIONS a) Compliance b) Design Effectiveness c) Areas in Flood Hazard Zones 5) REFERENCES APPENDIX A: MAPS AND EXHIBITS APPENDIX B: HYDROLOGIC CALCULATIONS APPENDIX C: HYDRAULIC CALCULATIONS SIGNATURE BLOCKS ENGINEER'S STATEMENT LARRY G. BODYFELT STATES THAT I AM BY OCCUPATION A PROFESSIONAL ENGINEER (CIVIL) AND LAND SURVEYOR EMPLOYED BY OXY USA INC. TO PREPARE A DRAINAGE REPORT FOR CASCADE CREEK 697-16-16 ANNEX STORAGE AREA IN ACCORDANCE WITH THE COLORADO OIL AND GAS COMMISSION (COGCC) REGULATIONS, GARFIELD COUNTY REGULATIONS AND THAT THE WORK WAS DONE UNDER MY AUTHORITY AND SUPERVISION COMMENCING OCTOBER 15, 2014. I ALSO STATE THAT THE DESIGN IS COMPLIANT WITH THE NORMAL AND CUSTORMARY INDUSTRY STANDARD OF PRACTICE FOR THIS TYPE AND NATURE OF WORK. LARRY G. BODYFELT, WYOMING PROFESSIONAL ENGINEER (CIVIL) AND LAND SURVEYOR NO. 3507 OWNER'S STATEMENT REVIEWED AND APPROVED BY: MICHAEL C. LOCK, COLORADO PROFESSIONAL ENGINEER NO. 37933 OXY USA INC. HAS REVIEWED THE DRAINAGE REPORT FOR CASCADE CREEK 697-16-16 ANNEX STORAGE AREA AND ACCEPTS THE RESPONSIBILITY FOR IMPLEMENTING AND MAINTAINING REQUIRED DRAINAGE MITIGATION PROCEDURES. GARY GROVE, OXY USA INC. INTRODUCTION a) Background The CASCADE CREEK 697-16-16 Annex Storage Area is used to store equipment and surplus materials for use in the Cascade Creek field and surrounding areas. The site was previously graded and developed for use as a well pad. Stormwater and drainage features currently exist. This report analyzes stormwater flows on and around the existing pad area and change in stormwater runoff quantity resulting from the existing location during expected flows for design storm events. b) Project Location The CASCADE CREEK 697-16-16 Annex Storage Area contains 4.82 acres located in the NE 1/4 of Section 16 and NW% of Section 15, Township 6 South, Range 97 West, 6th Principal Meridian, Garfield County, Colorado. The site is located on top of a ridge which is advantageous for controlling stormwater. Driving directions to the CASCADE CREEK 697-16-16 Annex Storage Area are described as follows: Beginning at the town of DeBeque, Colorado; travel northwesterly on County Road 204 for 5.4 miles to an existing access road, turn right and travel this road for 19.5 miles to the Cascade Creek 610-24-43 access road. Turn left and travel southwesterly 0.2 mile to the access road. Continue southwesterly for 0.3 miles to CASCADE CREEK 697-16-16 Annex Storage Area. Site coordinates are approximated in NAD 83 Datum as: Latitude: 39.528154° N Longitude: 108.215877° W C) Property Description The CASCADE CREEK 697-16-16 Annex Storage Area is located on a large Oxy USA property with no nearby property boundaries. The CASCADE CREEK 697-16-16 Annex Storage Area is located on the top of a ridge generally bounded on the east by the 2:1 (H:V) slope of an existing drainage basin, bounded on the south and west by an existing 2:1 slope and bounded on the northwest by an existing field access road. The surface of the CASCADE CREEK 697-16-16 Annex Storage Area are mostly bare dirt with a small amount of gravel intermixed. Side slopes within the Stormwater Analysis Area are either mostly bare or lightly covered with grasses and other vegetation. CASCADE CREEK 697-16-16 Annex Storage Area is zoned as Resource Lands as indicated by the Garfield County Zone District Map. d) Previous Investigations To our understanding, no previous investigations of the CASCADE CREEK 697-16-16 Annex Storage Area drainage have been conducted or approved regarding this location. 2) DRAINAGE SYSTEM DESCRIPTION a) Basin Descriptions See Sheet 2 of 4 of Appendix A for a map of the delineated watersheds. Stockpiled snow will be directed toward BMPs when practical to allow treatment. Plowed snow will likely be placed near the outer boundary of the pad so pad swales will collect the snow melt and route it to the sediment traps. W1 is the 0.30 acre basin which includes part of the access road to the CASCADE CREEK 697-16-16 Annex Storage Area and the area to the northwest of the access road to the disturbance limit. Stormwater accumulating on W1 is collected in swale S1 and directed in a road ditch to the west to design point 1, where it is discharged down the slope to the west. W2 is the 0.41 acre basin which includes part of the access road to the CASCADE CREEK 697-16-16 Annex Storage Area and the area northeast of the access road to the disturbance limit. Stormwater accumulating on W2 is collected in swale S2 and directed in a road ditch to the south to design point 2, where it is discharged through an existing 30" culvert and down the slope to the south. W3 is the 0.37 acre basin which includes part of the access road to the CASCADE CREEK 697-16-16 Annex Storage Area and the area south of the access road to the disturbance limit. Stormwater accumulating on W3 is collected in swale S3 and directed in a road ditch to the south to design point 3, where it is discharged down the slope to the south. W4 is the 1.00 acre basin which includes the access road to the west of the northern pad area of the CASCADE CREEK 697-16-16 Annex Storage Area and the western portion of the northern pad area. Stormwater accumulating on W4 is collected in swale S4 and directed in a road ditch to the south which routes water to the sediment trap at the bottom of the slope at design point 4, before being released by sheet flow or small rills down the slope to the west. W5 is the 1.03 acre basin which includes the access road to the east of the northern pad area of the CASCADE CREEK 697-16-16 Annex Storage Area and the eastern portion of the northern pad area. Stormwater accumulating on W5 is collected in swale S5 and directed in a road ditch to the south to design point 5, where it is discharged down the slope to the east. W6 is the 0.32 acre area which includes the southern portion of the northern pad area of the CASCADE CREEK 697-16-16 Annex Storage Area. Stormwater accumulating on W6 is collected in swale S6 and directed in a ditch to be constructed along the south slope which routes water to design point 5, where it is discharged down the slope to the east. WH is the historic location of the Stormwater Analysis Area which includes all the previously defined basins and covers 3.43 acres. This location was located on the top of a ridge and stormwater which fell within this boundary exited in nearly every direction by way of sheet flows and small rills. b) Existing Drainage Conditions The existing conditions of the CASCADE CREEK 697-16-16 Annex Storage Area consists of a relatively level pad area with projecting 2:1 slopes extending to the west and east pad edges down to catch with native contours, and with projecting 2:1 slopes extending to the south to catch with an existing well location. Soil conditions on the pad are mainly graded and leveled travel surfaces. All basins in the Stormwater Analysis Area have a hydrologic soil group C designation which has "moderately high runoff potential when thoroughly wet" as defined by the Natural Resources Conservation Service (NRCS). See the hydrologic soil group map produced by the NRCS in Appendix B. The Stormwater Analysis Area is located so that no water flows onto the location from any direction. Stormwater that falls within the Stormwater Analysis Area is either retained in small puddles, or collected in drainage ditches and released. c) Offsite Drainage The location of the CASCADE CREEK 697-16-16 Annex Storage Area was built on a ridge so that stormwater falling on the surrounding area does not flow into the Stormwater Analysis Area. d) Proposed Drainage System Description See Sheet 2 of 4 of Appendix A and Appendix C for the proposed dimensions of each swale. The V shape swales are to be graded with maximum 3:1 slopes at a total depth as shown on Sheet 2 of 4. Extra soil due to swale grading shall be stockpiled on the downhill side of the swale and compacted to form a small berm. Swales shall not have a minimum slope less than 0.75%. Hydraulic calculations show water velocity through each swale will not be greater than 5 feet per second with the expected flow rates during a 100 year, 24 hour storm event, and existing slopes. As a result, no energy dissipating and erosion controlling measures should be required. The existing sediment trap at design point 4 will be utilized to dissipate energy and remove excess sediment before water is released to undisturbed ground. The sediment trap should be constructed as directed by the Urban Storm Drainage Criteria Manual available from the Urban Drainage and Flood Control District with appropriate compaction and riprap outlet. While additional erosion mitigation measures are not expected to be needed, measures shall be taken if erosion issues appear. If more than minor rills occur at the bottom of slopes, wattle logs shall be placed at the bottom of steep slopes in problem areas using "J -hook" methods as described in the Urban Storm Drainage Criteria Manual. If excessive erosion occurs on the steep slopes, erosion control blankets shall be installed according to the Urban Storm Drainage Criteria Manual and the area reseeded and mulched as needed until sufficient vegetation is reestablished to prevent erosion. If stormwater flow through the proposed swales cause damage or change to the swale shape, the swale shall be repaired and wattle logs or riprap shall be installed in the swales at regular intervals in check dam fashion along the length of the swale. Installation of riprap or wattle log check dams shall be as directed by the Urban Storm Drainage Criteria Manual. e) Drainage Facility Maintenance Owner will be required to perform regular maintenance of swales, wattle logs, erosion control mats and sediment trap. Swales should be graded or cleaned out every one to three years or as needed after all significant storm events. Wattle logs should be maintained as needed to retain erosion mitigation properties. Erosion control mats should be maintained and the area reseeded and mulched until the slope is sufficiently stabilized by vegetation. The sediment trap should be dredged and re -graded as needed to maintain depth, dimensions and side slopes. It is not anticipated that additional soil will be disturbed for the use of the proposed site. In the event that soil is moved, the excess soil will be spread out to blend with existing contours and slopes will be kept to a minimum to promote vegetative regrowth and limit erosion. 3) DRAINAGE ANALYSIS AND DESIGN CRITERIA a) Regulations Production of this drainage report follows normal and customary engineering practices for this type and nature of work. Regulations from the Garfield County Land Use and Development Code 7-204 were applied as minimum standards. b) Development Criteria No known drainage constraints have been previously placed on CASCADE CREEK 697-16- 16 Annex Storage Area site due to drainage studies, floodplain studies or a master drainage plan. Drainage systems were designed to limit downstream erosion. c) Hydrologic Criteria Hydrologic calculations performed on the Stormwater Analysis Area were according to normal and customary engineering practices. The rational method was utilized in development of hydrologic design storms and runoff. See Appendix B for all hydrologic calculations. d) Hydraulic Criteria Hydraulic calculations performed during drainage design of the Stormwater Analysis Area drainage systems were according to normal and customary engineering practices. Hydraulic flow through each swale was estimated using Manning's Equation. See Appendix C for hydraulic calculations. 4) CONCLUSIONS a) Compliance This report has been prepared in accordance with normal and customary engineering practices for this type and nature of work. b) Design Effectiveness With proper application of the proposed drainage mitigation design presented in this report, runoff effects onto areas downstream of the Stormwater Analysis Area for design storms will be alleviated. c) Areas in Flood Hazard Zones There are no flood hazard zones designated by FEMA for the Stormwater Analysis Area. The Stormwater Analysis Area is classified as Zone D. 5) REFERENCES 1.) Stormwater Management Manual Grand Junction Municipal Code Title 26, December 4, 2013 2.) Urban Storm Drainage Criteria Manual Volume 3, Stormwater Best management Practices, November 2010 3.) Hydrology National Engineering Handbook Hydrologic Soil Groups United States Department of Agriculture Natural Resources Conservation Service Part 630 Chapter 7, May 2007 4.) Zone District Map, Garfield County, CO, December 16, 2013 5.) FEMA Flood Insurance Rate Map, Garfield County Colorado, Map Number 0802051ND0A, August 2, 2006 APPENDIX A: MAPS AND EXHIBITS 12/23/2014 J:\14000\14623\Drainage_Report\14623-AS-BLT DRAINAGE STUDY.dwg 4, 'A.� 1S' "._.-.' • P =fie � � . � :--1_ 0 _ _2000 _ \N COLORADO ,, . ': \,,f : t i /7,sif OXY USA INC (1/3) JOJO PROPERTIES (1/3) _. ` ��\\\ KOEHLER, DONNA J (1/3) RICHARD L. PRATHER (1/3) ;-' LYLE PRATHER (1/3) NED PRATHER (1/3) �.v I i n. it PETROLEUM 1\ DEVELOPMENT ; J, �+ ' ! ` CASCADE CREEK 697-16-16 ,,/ �/ ANNEX STORAGE AREA STORMWATER ANALYSIS 6,900 ;14! NO. A DATE 12/05/2014 12/15/2014 12/23/2014 REVISIONS DESCRIPTION ISSUED FOR CLEIENT REVIEW ISSUED FOR CLIENT REVIEW ISSUED FOR CLIENT REVIEW BY TKM CSW TKM CHK LGB LGB LGB APPR IAA • ricRIFFIN & ASSOCIATES, INC. "1141k OXY 16, TOPOGRAPHIC MAP 1414 ELK ST., SUITE 202 ROCK SPRINGS, WY 82901 (307) 362-5028 CASCADE CREEK 697-16-16 ANNEX STORAGE AREA STORMWATER ANALYSIS SCALE: 1" = 2,000' JOB No.: 14623 GARFIELD COUNTY, COLORADO 1 4623 -SW -ANALYSIS REV C SHEET 1 OF 4 rn 4623 -AS -BLT DRAINAGE STUDY.d inage_Report\ a N 0 2/23/2014 J: STAMP BY SURVEYOR I, RICHARD A. BULLEN JR., AN EMPLOYEE AND AGENT FOR D.R. GRIFFIN & ASSOCIATES, INC. STATE THE PLAT HEREON IS A CORRECT REPRESENTATION OF A SURVEY MADE UNDER MY AUTHORITY COMMENCING ON OCTOBER 15, 2014 OF THE SHOWN CASCADE CREEK 697-16-16 ANNEX STORAGE AREA . COLORADO PLS No. 28647 BASIS OF BEARINGS/ELEVATION THE BASIS OF BEARINGS FOR THIS SURVEY IS REFERENCED TO THE WEST LINE OF SECTION 15, T. 6 S., R. 97 W. OF THE 6TH P.M. AS BEARING S 01°43'17" W, THE TERMINUS OF THE SAID LINE BEING MONUMENTED WITH GLO BRASS CAPS AS SHOWN. THE BASIS OF ELEVATIONS FOR THIS SURVEY IS REFERENCED FROM USGS SPOT ELEVATION LOCATED IN THE SOUTHEAST QUARTER OF SECTION 15, T. 6 S., R. 97 W. WITH AN ELEVATION OF 8,432 FEET. LEGEND — - — -- BASIN BOUNDARY -4.0% I S1 CONTOURS (2 FOOT INTERVAL) DRAINAGE FLOW DESIGN POINT DRAINAGE SWALE - - --- '-- EXISTING/PROPOSED DRAINAGE SWALE SEC. 9, T 6 S, R 97 W SEC. 16, T 6 S, R 97 W NORTHWEST CORNER —\ SECTION 15 \ olll ( 1).• olll 121// ll/Ill /r„,%;,,%�Jr%I/7,////,%%/,i%//%1111%%/f%J/ tiff�lf/ //J l// //l /f jlll %%111% /,'IP /JJ111fr1/l1/llj11(Jll fff/1/I l ll/ollll•p' I /////1/I1////:/\ IJJr lmlJ l °> 111 I l!l ! l,..--- .///' //' �j/�//%%rri�% ,//J Jl // /7/ /% 1 /,/, %//J/J/l//////,//////////,-// /J /r�:�% N /(h1//O�jO,wAj //�� �1 I Ill /% (11JNI / / 11:f% /l //. i. , / , / / / / / / / /`r/1/ ///l 1111 / / i�.-..,,,,/(Il// f''rr \ f l//l !/lIJI'- n,, / / //1111///J//`' / / r l//// f /f 1 1 ' I 1 / l 11 l %/ // //l /, /!/////////,,, / ,//,, ,/,�/./� i;, / / / �//r/elf////////iN/ i J/ / (i../� l• / / � J l I �llll r-' il / /(iiii%i/l%i%iiiii// ii%%%l /� r`�/J�/ i�iJ/�iii/%%ji(J/ iSSNOWSTORAGEEE NOTE 8 RAREA f\\-/ --,, , ,///,",/ //�%/j%%J//',//j%J//JI,J/ :.1/.. rl ////ll/l in,,, /11/11; 1 //j,: •/i, it J / /,, l \ \ii'/%iii%i1/:/ 'iJ///////////) f///j / ,/ /),/,), / / ,,,,/,; '1 /l///(ff///i ///1 /i / / J 1////// / / / / / \I\ \ //7///// // /,,/r//////iii'///f//�, / 1 /////,///,/,,),///11/‘ /)//r/ �/(11j /j/� )' //ij/%'/ /lel // / / l ,1/1/".,;/ / // ii%1111//////r//,/, �/ f/ / /1/ii,////N///i! /1 //'/1(1/ /7/ "//1111/) J/ I / 1 ! 1 / / / l •••;(‘ / , 1111/// ////////21 / 1// J 'r/////// /r//r//l,/ ;`rl1 //////i/JJIJ,'� 1///l 1 \ i,// / // /4////1///////i/////f1/z / / / /Jr/1/ / /(///////•i////////// / ///•i/ f/J�i%l1/11 /,/// o rno / / /' /// // / %%i%�'///1/1//i%' 1/ / (/r / �/ /J //'/moi,/ ////////fl l //� /)/ f/�/ ., // q�\r\ \\/iii I / / /,//1111//////////11 J / J / / / //////////////f /) ///////c�G ////,l/\ \/// / /' %/%///i// 1111%// // //,/ %/ / / / / / i, / „// /// /,/l� �// /^p\ / %//1/ll/ �r ' // /iii'/ �ii�//�/i i�'/'/' i r CASCADE CREEK 69716-16 iir/ /f� :::://://///.///f//j//i/i/iiii_— , ' / / /;l//,i1/ ////i/"/ 1' // /rt,„ ; ANNEX STORAG::: AREA .���i// `'//''1111/ ////J/,» /iir// / / CENTEROF STORWATER'J J/ / / / // i/ //i%J/jl%%////f(/(�/f/ rlJ�i//lr /' !ANALYSAREA // ;/,i///11X"(l . i %ii/i/ij'�J11///Ji ////�1 /( LAT: 39.8154° N / �o r/ i // //i/�//llili�ijJiJ�%�J//i/��i�/ //i')/�f// IJLONG1108.2877°W, �ry / i/iii i/rl�/� �i i//�fiii�/�(Jil ii/ii/i�ii�iil��i Ji%/Ili i/ii/ii; ��r;NAD8D�ATUM�//% �i/iii// i j 1111%/////JJJ/j J///f%�f%%/�///(!ll///1111/!J//11111////j/(/'r/f/(/f/�///%%jJl� fN j ;/�///// 'iii,/,,,,i APPENDIX B: HYDROLOGIC CALCULATIONS 739090 739150 Custom Soil Resource Report Map—Hydrologic Soil Group 739210 739270 739330 739390 739450 39° 31' 47' N m— rn M 39° 31' 31" N 739150 739210 Map Scale: 1:2,470 if printed on A portrait (8.5" x 11") sheet. 739270 739330 0 35 70 140 0 100 200 Feet 400 600 Meters 210 Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UM Zone 12N WGS84 18 739390 739450 Custom Soil Resource Report MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons 0 A 0 ND 0 0 B/D 0 0 C/D 0 D 0 Not rated or not available Soil Rating Lines • s A eke A/D err B err B/D err C eke C/D eke D ✓ r Not rated or not available Soil Rating Points o A ® ND ■ B ■ B/D o c ▪ C/D ▪ D o Not rated or not available Water Features Streams and Canals Transportation t++ Rails okre Interstate Highways US Routes Major Roads Local Roads Background III Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties Survey Area Data: Version 7, Sep 22, 2014 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jun 22, 2010—Sep 2, 2010 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background gery displayed on these maps. Asa result, some minor shifting 19 of map unit boundaries may be evident. Custom Soil Resource Report Table—Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit — Douglas -Plateau Area, Colorado, Parts of Garfield and Mesa Counties (C0682) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 52 Northwater-Adel complex, 5 to 50 percent slopes B 4.9 15.2% 56 Parachute-lrigul-Rhone association, 25 to 50 percent slopes C 27.6 84.8% Totals for Area of Interest 32.5 100.0% Rating Options—Hydrologic Soil Group Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher 20 Precipitation Frequency Data Server http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=39.5270&1... NOAA Atlas 14, Volume 8, Version 2 Location name: De Beque, Colorado, US* Latitude: 39.5270°, Longitude: -108.2168° Elevation: 8278 ft* * source: Google Maps POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Deborah Martin, Sandra Pavlovic, Ishani Roy, Mchael St. Laurent, Carl Trypaluk, Dale Unruh, Mchael Yekta, Geoffery Bonnin NOM, National Weather Service, Silver Spring, Maryland PF tabular 1 PF graphical 1 Maps & aerials PF tabular PDS -based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5 -min 0.150 0.187 0.256 0.321 0.423 0.511 0.608 0.714 0.868 0.994 (0.119-0.192) (0.149-0.239) (0.203-0.328) (0.253-0.414) (0.326-0.581) (0.382-0.708) (0.437-0.863) (0.490-1.04) (0.571-1.30) (0.631-1.50) 10 -min 0.220 0.274 0.375 0.470 0.620 0.749 0.890 1.05 1.27 1.46 (0.175-0.280) (0.217-0.350) (0.297-0.480) (0.370-0.605) (0.478-0.851) (0.559-1.04) (0.639-1.26) (0.718-1.53) (0.836-1.91) (0.925-2.20) 15 -min 0.268 0.334 0.457 0.573 0.756 0.913 1.08 1.28 1.55 1.78 (0.213-0.342) (0.265-0.426) (0.362-0.585) (0.451-0.738) (0.582-1.04) (0.682-1.26) (0.780-1.54) (0.875-1.86) (1.02-2.33) (1.13-2.68) 30 -min 0.374 0.477 0.659 0.823 1.07 1.27 1.49 1.72 2.05 2.31 (0.298-0.478) (0.379-0.610) (0.522-0.845) (0.648-1.06) (0.816-1.45) (0.944-1.75) (1.06-2.10) (1.18-2.50) (1.34-3.06) (1.47-3.49) 60 -min 0.480 0.606 0.823 1.01 1.29 1.51 1.75 2.00 2.35 2.62 (0.382-0.613) (0.482-0.774) (0.651-1.05) (0.797-1.30) (0.983-1.74) (1.12-2.07) (1.25-2.46) (1.37-2.90) (1.54-3.50) (1.67-3.96) 2 -hr 0.586 0.734 0.986 1.20 1.51 1.76 2.02 2.28 2.65 2.94 (0.471-0.738) (0.590-0.927) (0.789-1.25) (0.956-1.53) (1.16-2.01) (1.32-2.37) (1.45-2.79) (1.57-3.25) (1.75-3.89) (1.89-4.37) 3 -hr 0.660 0.803 1.05 1.26 1.56 1.81 2.06 2.33 2.70 3.00 (0.533-0.826) (0.648-1.01) (0.842-1.31) (1.01-1.59) (1.21-2.06) (1.36-2.42) (1.50-2.83) (1.62-3.30) (1.80-3.94) (1.94-4.42) 6 -hr 0.797 0.937 1.18 1.39 1.68 1.93 2.18 2.44 2.80 3.09 (0.651-0.985) (0.765-1.16) (0.957-1.46) (1.12-1.73) (1.32-2.19) (1.47-2.54) (1.60-2.94) (1.72-3.40) (1.89-4.02) (2.03-4.49) 12 -hr 0.973 1.11 1.35 1.56 1.87 2.13 2.40 2.70 3.11 3.44 (0.803-1.19) (0.914-1.36) (1.11-1.65) (1.27-1.92) (1.49-2.41) (1.65-2.78) (1.79-3.22) (1.93-3.72) (2.13-4.41) (2.29-4.93) 24 -hr 1.17 1.33 1.60 1.84 2.20 2.50 2.81 3.15 3.63 4.01 (0.977-1.41) (1.10-1.60) (1.33-1.93) (1.52-2.24) (1.77-2.79) (1.96-3.21) (2.13-3.72) (2.28-4.29) (2.52-5.08) (2.70-5.67) 2 -day 1.39 1.60 1.96 2.26 2.71 3.06 3.43 3.82 4.35 4.77 (1.17-1.65) (1.35-1.91) (1.64-2.34) (1.89-2.72) (2.19-3.37) (2.42-3.87) (2.61-4.45) (2.79-5.10) (3.05-5.98) (3.25-6.64) 3 -day 1.56 1.80 2.20 2.54 3.04 3.44 3.85 4.29 4.88 5.34 (1.32-1.84) (1.52-2.13) (1.86-2.61) (2.14-3.03) (2.48-3.76) (2.73-4.32) (2.96-4.96) (3.15-5.67) (3.45-6.65) (3.68-7.38) 4 -day 1.70 1.96 2.39 2.77 3.30 3.73 4.18 4.64 5.28 5.78 (1.45-2.00) (1.67-2.30) (2.03-2.82) (2.33-3.28) (2.70-4.06) (2.98-4.65) (3.22-5.34) (3.44-6.11) (3.76-7.15) (4.00-7.94) 7 -day 2.04 2.34 2.84 3.27 3.88 4.36 4.86 5.38 6.08 6.63 (1.75-2.37) (2.01-2.72) (2.43-3.31) (2.78-3.83) (3.20-4.71) (3.51-5.37) (3.78-6.13) (4.02-6.98) (4.37-8.12) (4.64-8.98) 10 -day 2.33 2.65 3.19 3.65 4.30 4.81 5.33 5.88 6.61 7.17 (2.01-2.69) (2.29-3.06) (2.75-3.70) (3.13-4.25) (3.57-5.18) (3.90-5.88) (4.18-6.68) (4.42-7.57) (4.78-8.75) (5.06-9.65) 20 -day 3.15 3.52 4.14 4.67 5.39 5.96 6.54 7.12 7.91 8.52 (2.75-3.58) (3.08-4.02) (3.61-4.74) (4.04-5.36) (4.52-6.38) (4.89-7.16) (5.18-8.05) (5.42-9.02) (5.80-10.3) (6.09-11.3) 30 -day 3.84 4.29 5.01 5.61 6.44 7.07 7.70 8.34 9.18 9.81 (3.38-4.34) (3.77-4.85) (4.39-5.68) (4.89-6.39) (5.43-7.54) (5.83-8.41) (6.15-9.39) (6.39-10.4) (6.78-11.8) (7.07-12.9) 45 -day 4.74 5.31 6.24 6.99 7.98 8.73 9.46 10.2 11.1 11.8 (4.19-5.31) (4.70-5.96) (5.50-7.02) (6.13-7.89) (6.76-9.24) (7.24-10.3) (7.59-11.4) (7.85-12.6) (8.25-14.1) (8.55-15.3) 60 -day 5.51 6.23 7.38 8.28 9.47 10.3 11.2 12.0 13.0 13.7 (4.90-6.14) (5.54-6.95) (6.54-8.25) (7.30-9.30) (8.05-10.9) (8.61-12.1) (9.01-13.4) (9.28-14.7) (9.68-16.4) (9.99-17.7) 1 Precipitation frequency PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for 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 are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical 1 of 4 11/26/2014 9:36 AM F tirt Coll O ao',CCtv�l�ndo' L:ngmo :I-iouI1 Den Arapaho Naiiohe. 1ore.sf 0 ;i; 7. nt Precipitation Frequency Data Server http://hdsc.nws.noaa.gov/hdsc/pfds/pfds printpage.html?lat=39.5270&1... PDS -based depth -duration -frequency (DDF) curves Latitude: 39.5274°, Longitude: -108.2168" 14 12 c 10 a.., w 8 c a E ▪ 4 0 e e ,E .E 6 LA r-1 6G 1- 1- � L N1 1 L l�J 1 L tV '-I Duration 4 t9 C N r6 4 7 r c r r r{7 co N D O O irid N In V 11121 1 L 1 1 5 10 25 50 100 200 NOAA Atlas 14, Volume 8, Version 2 500 1000 Average recurrence interval (years) Created {GMT): Wed Nov 26 16:31:06 2014 Back to Top Maps & aerials Small scale terrain Average recurrence interval {years) 1 2 5 10 25 50 100 200 500 1000 Duration 5 -min — 2 -day 10 -min — 3 -day 15 -min — 4 -day 30-m1n 7 -day 60-lnin — 10 -day — 2 -hr — 20 -day 3 -hr 30 -Jay — 6 -hr — 45 -day 12 -hr — 60 -day 24 -hr Grand Jonciioii 50 km ,Nap data © Report a map error 2 of 4 11/26/2014 9:36 AM Precipitation Frequency Data Server http://hdsc.nws.noaa.gov/hdsc/pfds/pfds printpage.html?lat=39.5270&1... Large scale terrain tI/ >r - 2 km Large scale map 2 km Large scale aerial Map Repoi€ a map error Map Report a map error 2 k Imagery C Report amei error Back to Top 3 of 4 11/26/2014 9:36 AM Design Storms 1 HOUR DURATION DESIGN RAINFALL OBTAINED FROM NOAA ATLAS 14, VOLUME 8, VERSION 2 RECURANCE INTERVAL (YEARS) DEPTH (INCHES) 2 YEAR 0.606 5 YEAR 0.823 10 YEAR 1.010 25 YEAR 1.290 50 YEAR 1.510 100 YEAR 1.750 24 HOUR DURATION DESIGN RAINFALL OBTAINED FROM NOAA ATLAS 14, VOLUME 8, VERSION 2 HYDROLOGIC CALCULATIONS CASCADE CREEK 697-16-16 ANNEX STORAGE AREA Oxy USA RECURANCE INTERVAL (YEARS) DEPTH (INCHES) 2 YEAR 1.330 5 YEAR 1.600 10 YEAR 1.840 25 YEAR 2.200 50 YEAR 2.500 100 YEAR 2.810 1 of 5 Job # 14623 D.R. Griffin Associates, Inc. Rock Springs, WY 307-362-5028 Composite Runoff Coefficients "C" Basin I.D. Soil Group C&D (%) Undeveloped (%) Gravel Road (%) Impervious (%) Runoff Coefficients Soil Type C&D 5YR 25 YR 100 YR W1 100.0% 0.0% 100.0% 40.0% 0.35 0.50 0.58 W2 100.0% 0.0% 100.0% 40.0% 0.35 0.50 0.58 W3 100.0% 0.0% 100.0% 40.0% 0.35 0.50 0.58 W4 100.0% 0.0% 100.0% 40.0% 0.35 0.50 0.58 W5 100.0% 0.0% 100.0% 40.0% 0.35 0.50 0.58 W6 100.0% 0.0% 100.0% 40.0% 0.35 0.50 0.58 WH 100.0% 100.0% 0.0% 2.0% 0.17 0.39 0.51 HYDROLOGIC CALCULATIONS CASCADE CREEK 697-16-16 ANNEX STORAGE AREA Oxy USA 2 of 5 Job # 14623 D.R. Griffin Assoicates, Inc. Rock Springs, WY 307-362-5028 Time of Concentration Sub -Basin Data Init. Overland Time( Ti) Travel Time (Tt) Total Tc Check (Urbanized Basins) Basin C5 Area (AC) Lo (ft) Slope % Ti (Min.) Land Type Cv Length Slope % Vel. (FPS) Tt (Min) Ti+Tt (Min) Lgth. (Ft) Tc W1 0.35 0.30 100 2.5 9.95 BARE 10 271 2 1.41 3.19 13.14 371 12.06 W2 0.35 0.41 150 9 7.95 BARE 10 408 9 3.00 2.27 10.22 558 13.10 W3 0.35 0.37 150 9 7.95 BARE 10 252 9 3.00 1.40 9.35 402 12.23 W4 0.35 1.00 300 1.5 20.43 BARE 10 323 6 2.45 2.20 22.62 623 13.46 W5 0.35 1.03 300 1.5 20.43 BARE 10 336 5 2.24 2.50 22.93 636 13.53 W6 0.35 0.32 100 1.5 11.79 BARE 10 270 2 1.41 3.18 14.98 370 12.06 WH 0.17 3.43 300 25 9.92 PASTURE 7 650 25 3.50 3.10 13.01 950 15.28 Formulas: Notes: Ti=1.8(1.1-Cs)Lo^0.5/(S^1/3) 1.) Cs = 5 year runoff coefficient V=Cv*(S/100)^0.5 2.) Lo = Length of overland flow, 300' maximum. Tc=(L/180)+10 3.) Overland Time and Travel Time Slope % derived from survey data and Lidar data. HYDROLOGIC CALCULATIONS CASCADE CREEK 697-16-16 ANNEX STORAGE AREA Oxy USA Page 3 of 5 Job # 14623 D.R. Griffin Associates, Inc. Rock Springs, WY 307-362-5028 Rational Method Procedure Design Storm: 25 -Year Developed Direct Runoff Design Point Swale(s) Basin Area (AC) Imperv. Coeff. (C) Tc (Min.) C*A Pi I (in/hr.) Q (cfs) 1 51 W1 0.30 0.40 0.50 13.14 0.15 1.29 3.16 0.47 2 52 W2 0.41 0.40 0.50 10.22 0.20 1.29 3.51 0.72 3 53 W3 0.37 0.40 0.50 9.35 0.19 1.29 3.63 0.68 4 S4 W4 1.00 0.40 0.50 22.62 0.50 1.29 2.41 1.20 5 55 W5 1.03 0.40 0.50 22.93 0.51 1.29 2.39 1.23 5 56 W6 0.32 0.40 0.50 14.98 0.16 1.29 2.97 0.47 WT 3.43 4.77 WH 3.43 0.02 0.39 13.01 1.34 1.29 3.17 4.24 Formulas: 1=28.9*Pi/(10+Tc)^0.786 Q=CIA HYDROLOGIC CALCULATIONS CASCADE CREEK 697-16-16 ANNEX STORAGE AREA Oxy USA Notes: Pi = Point rainfall for one-hour duration. See Design Storms. Page 4 of 5 Job # 14623 D.R. Griffin Associates, Inc. Rock Springs, WY 307-362-5028 Rational Method Procedure Design Storm: 100 -Year Developed Direct Runoff Ditch Travel Time Design Point Basin Area (AC) Imperv. (dec) Coeff. (C) Tc (Min.) C*A Pi I (in/hr.) Q (cfs) Slope % Flow (cfs) Length (Ft) Velocity (fps) Travel Time (Min) 1 W1 0.30 0.40 0.58 13.14 0.17 1.75 4.28 0.74 2.0 0.74 271 1.80 2.51 2 W2 0.41 0.40 0.58 10.22 0.24 1.75 4.76 1.13 9.0 1.13 408 3.46 1.97 3 W3 0.37 0.40 0.58 9.35 0.22 1.75 4.93 1.07 9.0 1.07 252 3.48 1.21 4 W4 1.00 0.40 0.58 22.62 0.58 1.75 3.27 1.89 6.0 1.89 323 3.41 1.58 5 W5 1.03 0.40 0.58 22.93 0.60 1.75 3.24 1.94 5.0 1.94 336 3.19 1.76 5 W6 0.32 0.40 0.58 14.98 0.18 1.75 4.03 0.74 2.0 0.74 270 1.80 2.50 WT 3.43 7.51 WH 3.43 0.02 0.51 13.01 1.75 1.75 4.30 7.51 Formulas: 1=28.9* P1/(10+Tc)^0.786 Q=CIA HYDROLOGIC CALCULATIONS CASCADE CREEK 697-16-16 ANNEX STORAGE AREA Oxy USA Notes: Pi = Point rainfall for one-hour duration. See Design Storms Page 5of5 Job # 11697 D.R. Griffin Associates, Inc. Rock Springs, WY 307-362-5028 APPENDIX C: HYDRAULIC CALCULATIONS v Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Dec 23 2014 S1-100YR Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.37 Total Depth (ft) = 1.00 Q (cfs) = 0.740 Area (sqft) = 0.41 Invert Elev (ft) = 50.00 Velocity (ft/s) = 1.80 Slope (%) = 2.00 Wetted Perim (ft) = 2.34 N -Value = 0.035 Crit Depth, Yc (ft) = 0.33 Top Width (ft) = 2.22 Calculations EGL (ft) = 0.42 Compute by: Known Q Known Q (cfs) = 0.74 Elev (ft) Section Depth (ft) 52.00 51.50 51.00 50.50 50.00 49.50 0 1 4 Reach (ft) 5 6 7 2.00 1.50 1.00 0.50 0.00 -0.50 8 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Dec 23 2014 S2-100YR Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) Total Depth (ft) = 1.00 Q (cfs) Area (sqft) Invert Elev (ft) = 50.00 Velocity (ft/s) Slope (%) = 9.00 Wetted Perim (ft) N -Value = 0.035 Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Calculations Compute by: Known Q (cfs) Known Q = 1.13 = 0.33 = 1.130 = 0.33 = 3.46 = 2.09 = 0.39 = 1.98 = 0.52 Elev (ft) Section Depth (ft) 52.00 51.50 51.00 50.50 50.00 49.50 0 1 4 Reach (ft) 5 6 7 2.00 1.50 1.00 0.50 0.00 -0.50 8 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Dec 23 2014 S3-100YR Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) Total Depth (ft) = 1.00 Q (cfs) Area (sqft) Invert Elev (ft) = 50.00 Velocity (ft/s) Slope (%) = 9.00 Wetted Perim (ft) N -Value = 0.035 Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Calculations Compute by: Known Q (cfs) Known Q = 1.07 = 0.32 = 1.070 = 0.31 = 3.48 = 2.02 = 0.38 = 1.92 = 0.51 Elev (ft) Section Depth (ft) 52.00 51.50 51.00 50.50 50.00 49.50 0 1 4 Reach (ft) 5 6 7 2.00 1.50 1.00 0.50 0.00 -0.50 8 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Dec 23 2014 S4-100YR Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) Total Depth (ft) = 1.00 Q (cfs) Area (sqft) Invert Elev (ft) = 50.00 Velocity (ft/s) Slope (%) = 6.00 Wetted Perim (ft) N -Value = 0.035 Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Calculations Compute by: Known Q (cfs) Known Q = 1.89 = 0.43 = 1.890 = 0.55 = 3.41 = 2.72 = 0.48 = 2.58 = 0.61 Elev (ft) Section Depth (ft) 52.00 51.50 51.00 50.50 50.00 49.50 0 1 4 Reach (ft) 5 6 7 2.00 1.50 1.00 0.50 0.00 -0.50 8 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Dec 23 2014 S5-100YR Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) Total Depth (ft) = 1.00 Q (cfs) Area (sqft) Invert Elev (ft) = 50.00 Velocity (ft/s) Slope (%) = 5.00 Wetted Perim (ft) N -Value = 0.035 Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Calculations Compute by: Known Q (cfs) Known Q = 1.94 = 0.45 = 1.940 = 0.61 = 3.19 = 2.85 = 0.49 = 2.70 = 0.61 Elev (ft) Section Depth (ft) 52.00 51.50 51.00 50.50 50.00 49.50 0 1 4 Reach (ft) 5 6 7 2.00 1.50 1.00 0.50 0.00 -0.50 8 v Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Dec 23 2014 S6-100YR Triangular Highlighted Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.37 Total Depth (ft) = 1.00 Q (cfs) = 0.740 Area (sqft) = 0.41 Invert Elev (ft) = 50.00 Velocity (ft/s) = 1.80 Slope (%) = 2.00 Wetted Perim (ft) = 2.34 N -Value = 0.035 Crit Depth, Yc (ft) = 0.33 Top Width (ft) = 2.22 Calculations EGL (ft) = 0.42 Compute by: Known Q Known Q (cfs) = 0.74 Elev (ft) Section Depth (ft) 52.00 51.50 51.00 50.50 50.00 49.50 0 1 4 Reach (ft) 5 6 7 2.00 1.50 1.00 0.50 0.00 -0.50 8