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Home My WebLink About20162993ce ce w w t7 Q O world of capabilities delivered locally APPENDIX B-3 DRAINAGE REPORT Pawnee Waste LLC Weld County, Colorado Prepared for: Pawnee Waste LLC 3003 E. Harmony, Suite 300 Fort Collins, CO 80528 Prepared by: Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 July 23, 2015 Revision 1 - February 19, 2016 1407882B Golder Associates February 2016 Appendix B-3 1407882E Rev. 1 Table of Contents 1.0 CERTIFICATION 1 2.0 INTRODUCTION 2 3.0 GENERAL LOCATION AND DESCRIPTION 3 3.1 Location 3 3.2 Description of Property 3 3.3 Description of Project 4 4.0 DRAINAGE BASINS AND SUB -BASINS 5 4.1 Major Basin Description 5 4.2 Sub -basin Description 5 5.0 DRAINAGE DESIGN CRITERIA 6 5.1 Development Criteria Reference and Constraints 6 5.2 Hydrological Criteria 6 5.3 Hydraulic Criteria 7 6.0 DRAINAGE FACILITY DESIGN 8 6.1 General Concept 8 6.2 Specific Details and Compliance with Weld County Code 8 6.2.1 Temporary Surface Water Management 9 6.2.2 Final Stormwater Management System 9 6.2.2.1 Run-on Diversion 9 6.2.2.2 Runoff Control 10 6.2.1 Erosion Potential Evaluation 11 6.2.2 Stormwater Controls Inspection and Maintenance 13 7.0 CONCLUSIONS 14 7.1 Compliance with the Weld County Code 14 7.2 Drainage Concept 14 8.0 REFERENCES 15 is\14\1407882b10400\0403 edop revl\appendix b\app b -3\1407882b app b-3 drainage plan 19feb16.docx Golder Associates February 2016 Appendix B-3 ii 1407882B Rev. 1 List of Tables Table B-3-1 Open Channel Summary Table List of Drawings Drawing B-3-1 Drawing B-3-2 Drawing B -3-3A Drawing B -3-3B Drawing B-3-4 Drawing B-3-5 Drawing B-3-6 List of Appendices Appendix B-3-1 Appendix B-3-2 Title Sheet Historic and Fully Developed (Run-on Diversion) Basins Fully Developed (Run-off Control) Basins Stormwater Controls Plan Details (1 of 3) Details (2 of 3) Details (3 of 3) Surface Water Runoff Controls Calculation Surface Water Run-on Controls Calculation i:1•14 \1407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 1407882E Rev. 1 Appendix B-3 1 1.0 CERTIFICATION "I hereby certify that this report for the final drainage design of the Pawnee Waste E&P Landfill was prepared by me (or under my direct supervision) in accordance with the provisions of the Weld County Storm Drainage Criteria for the owner, Pawnee Waste LLC." Jeff R s " P.E. State •f Colorado No. 0046801 i;51451407882b1040050403 edop revflappendix blapp b -311407882b app b-3 drainage plan 191eb16.docx Golder Associates February 2016 Appendix B-3 2 1407882B Rev. 1 2.0 INTRODUCTION This Drainage Report is prepared on behalf of the Applicant, Pawnee Waste LLC (Pawnee), in support of a Weld County Use by Special Review (USR) Permit Application for the Pawnee Waste E&P Landfill (Landfill or Facility). The Drainage Report follows the criteria set forth by Urban Storm Drainage Criteria Manuals (USDCM), Volumes 1, 2, and 3, and the Weld County Storm Drainage Criteria Addendum to the Urban Storm Drainage Criteria Manuals, Volumes 1, 2, and 3, dated October 2006. The design of the stormwater drainage controls presented herein is also intended to satisfy the applicable criteria from the Colorado Department of Public Health and Environment (CDPHE) "Regulations Pertaining to Solid Waste Sites and Facilities" (6 CCR 1007-2, Part 1). Pawnee is proposing to develop a Landfill on a 240 -acre contiguous property owned by Pawnee Waste LLC (Site) for the disposal of non -hazardous oil and gas exploration and production (E&P) waste. The proposed Landfill is approximately 74 acres, with an adjacent approximate 2.4 -acre stormwater detention pond. Additional areas within the 240 -acre property are to be developed for the proposed access roads, perimeter stormwater control channels, and entrance road and appurtenant infrastructure. i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 3 1407882B Rev. 1 3.0 GENERAL LOCATION AND DESCRIPTION 3.1 Location The proposed Facility will be located approximately four miles southeast of Grover, Colorado, in the northeast quarter and east half of the northwest quarter of Section 13, Township 10 North, Range 61 West of the 6th Principal Meridian. The Facility address is 57996 WCR 95, Grover, Colorado, 80729. The property is located approximately '/4 mile east of the intersection of Weld County Road (WCR) 118 and WCR 95 in Weld County. There are no local streets within the property. The property and surrounding land are zoned Agricultural, and the project site and surrounding land are under Weld County jurisdiction. There are no lakes, streams, or water resource facilities within the property. Historically, the property has been agricultural land; however, the area where the Landfill will be located has not been recently cultivated. There is a water pipeline owned by Grassland Water Solutions that conveys water through the Site. Water required for dust control will be delivered via a truck that will use the existing load -out system at the Grasslands Water Solutions site. Drinking water will be supplied via a pipeline to be constructed from an existing well owned by Grasslands Water Solutions. All required approvals will be obtained prior to construction for drinking water usage by Pawnee. There are no irrigation facilities serving the property or other water supply pipes conveying water through the Site. A property owned by Harold and Elaine Weisbrook bounds the Facility on the north side. A property owned by Dietzler Ranch and Cattle Company, LLC bounds the Facility on the east and south sides. Grassland Water Solutions owns the property on the west side of the Facility. 3.2 Description of Property The Landfill property is approximately 240 acres and is owned by Pawnee Waste LLC. Based on the topographic survey for the property, the topography is characterized by a relatively uniform slope of approximately 0.5 to 1%. Drainage across the proposed Site generally flows overland from a topographic high of 5,096.5 feet above mean sea level (ft amsl) in the northeastern corner of the Site southwestward to a topographic low of 5,058.4 ft amsl in the southwestern corner of the Site. Surface water is generally conveyed toward an intermittent waterway, Jackson Draw, located roughly 4,000 feet southwest of the proposed Site boundary. The Site topography is shown in Drawings B-3-2 and B -3-3A. Vegetation on the Site property is characterized by scattered grasses and sagebrush. There is one proposed access point to the new Facility. The existing WCR 118 will be extended east of the intersection with WCR 95 and will run parallel to the northern boundary of the property. The entrance road to the Facility will be constructed approximately 2,085 feet east of the WCR 118 and WCR 95 intersection, and will be routed southeastward to the scalehouse/entrance area and from there into the Landfill. United States Department of Agriculture — Natural Resources Conservation Service (USDA-NRCS) designates the dominant soil covering the proposed property as Kim -Mitchell complex and Stoneham fine i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 4 1407882B Rev. 1 sandy loam, composed primarily of silt and fine sandy loams. The parent materials for soils within this soil association are calcareous loamy alluvial deposits. The USDA-NRCS Soil Report generated for the Site is presented in Attachment B-3-2-3 of Appendix B-3-2. All Hydrologic Soil Groups (Group A, B, C, and D) are present at the Site. The predominant soil is characterized as having slow infiltration and water transmission rates and is assigned Hydrologic Soil Group C by the USDA-NRCS. These soils typically impede the downward movement of water and have a moderately -fine or fine texture. 3.3 Description of Project The proposed Landfill will be located in the eastern portion of the 240 -acre property. The proposed development will include an approximate 74 -acre landfill, perimeter access roads and stormwater control channels, and an approximate 2.4 -acre stormwater detention pond. Stormwater runoff will be conveyed southwestward into the proposed stormwater detention pond via three 42 -inch diameter corrugated metal culverts, or equivalent single -span box culvert structure, crossing beneath the west perimeter road. Channel grading and stormwater controls and for the proposed Landfill are shown in Drawing B -3-3B. A small stormwater catchment basin will be excavated downgradient (southwest) of the entrance/infrastructure facilities to act as a pollution prevention measure for runoff from the scale, parking, fueling, maintenance, and adjacent areas of concentrated vehicle traffic, with the general location shown in Drawing B -3-3B. The Landfill will be developed in a sequential manner as additional disposal areas are required. For construction and leachate management purposes, the Landfill has been subdivided into phases. The Landfill is anticipated to be developed in four main phases (i.e., Phase 1A, Phase 1B, Phase 2A, and Phase 2B). Pawnee will further divide construction of the main phases into sub -phases and/or cells. The sub -phase sizes will vary based on the estimated waste disposal capacity needs. Run-on and runoff controls will be established and maintained throughout the operation of each phase or sub -phase. Wherever a phase (or sub -phase) development area will terminate internal to the Landfill footprint (i.e., not along the final perimeter), a temporary termination berm will be constructed along the leading edge for containment of waste and leachate and to facilitate tie-in of future cells. Where the leading edge is on the upgradient side of the constructed area, a temporary run-on diversion channel/berm will also typically be installed, as needed, on the undeveloped land immediately upgradient of the termination to collect and redirect the stormwater flow away from the active area. Phased construction will progress in this manner until the entire Landfill is developed. This method of phased development will limit the amount of active (open) cell area at any given point in the Landfill development, minimize leachate generation, and allow closure of one phase while waste placement is occurring in another phase, at the discretion of Pawnee. i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 5 1407882B Rev. 1 4.0 DRAINAGE BASINS AND SUB -BASINS 4.A Major Basin Description The Site property is located in the South Platte River Basin, approximately 4,000 feet northeast of Jackson Draw, an intermittent waterway 36 miles north of the South Platte River. The South Platte River flows toward the northeast, and most of the land between the river and the Site is irrigated agricultural land. Any excess runoff from the property discharges to agricultural fields located to the southwest. The location of the property is shown in Drawings B-3-1 and B-3-2. The property is within a "Zone D" undetermined area per the Federal Emergency Management Agency (FEMA), which means a flood study has not been performed. Based on review of the local topography, including a site -specific topographic survey conducted in October 2014, the Site does not lie within a floodplain. 4.2 Sub -basin Description Historically and to the present day, runoff in the vicinity of the Site flows in a southwesterly direction following existing topographic features. A single relatively large (approximately 2.5 square miles) natural drainage basin north and east of the Site conveys runoff from off -site upgradient agricultural fields and undeveloped open land across the Site property, and onto the agricultural fields situated to the west and south. There are several defined flow -lines (ephemeral waterways) east and north of the property within this drainage basin; however, these flow -lines dissipate to become sheet flow upgradient of the proposed Landfill, and there are no defined flow -lines on or in the immediate vicinity of the Site. There are also no localized topographic ridges or depressions on the property. Sub -basins for the stormwater control design were delineated based on existing topography and planned final landfill grading, shown in Drawings B-3-2 and B -3-3A. Stormwater runoff from the Landfill will be conveyed by terrace channels, access road channels, downchutes, and perimeter channels to the stormwater detention pond located adjacent to the southwest side of the Landfill. Three 42 -inch diameter corrugated metal culverts (or an equivalent single -span box culvert structure) are designed at an approximately 1.8% slope to convey the peak flow rate of approximately 170 cfs beneath the west perimeter road and into the stormwater detention pond. Sediment will be captured within the stormwater detention pond by storing runoff and releasing it over a 40 -hour period through a perforated outlet riser pipe with a gravel filter to minimize the release of sediment laden water. Surface water run-on from off -site upgradient areas will be diverted around the Landfill via perimeter stormwater run-on diversion channels along the north and east Landfill boundaries. Run-on flow from off -site upgradient areas will not be allowed to mix with on -site stormwater runoff from the Landfill. i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 6 1407882B Rev. 1 5.0 DRAINAGE DESIGN CRITERIA This Drainage Report has been prepared based on criteria in the Weld County Storm Drainage Criteria (WCSDC) Addendum to the Urban Storm Drainage Criteria Manual (USDCM), and Volumes 1, 2, and 3 of the Urban Storm Drainage Criteria Manual. The applicable precipitation criteria used for design of the drainage controls for the proposed Facility is the 100 -year frequency, 24 -hour duration storm event. P 5: Development Criteria Reference and Constraints There is neither a project master plan nor a regional drainage master plan for the Facility, and no previous drainage studies have been performed. There are three known utilities within the Site property: • An underground natural gas pipeline in the southwest corner of the Site (owned and flagged by Noble Energy); • an underground water pipeline in the southwest corner of the Site (owned by Grassland Water Solutions and flagged by Intermill Land Surveying, Inc. during the ALTA survey); and ▪ an underground missile cable in the northeast corner of the Site (owned by the United States Air Force (USAF) and flagged by the USAF 90th Missile Maintenance Squadron). These utility lines were subsequently surveyed and are shown in Drawing B -3-3A. There are no existing structures, irrigation ditches, or streets within or associated with the Site. The gently -sloping topography of the Site, with the absence of existing defined drainage features, was considered in preparing the design for the proposed Facility stormwater controls and does not pose a significant design constraint. 5.2 Hydrological Criteria The design rainfall was obtained from the National Oceanic and Atmospheric Administration's (NOAA) Precipitation Frequency Data Server website. The values are based on NOAA Atlas 14, Volume 8, Version 2.0 published by NOAA. The latitude and longitude of the Facility was used to obtain the design rainfall depths for the project. The 2 -year frequency, 24 -hour duration storm event precipitation depth is 1.8 inches. The 5 -year frequency, 1 -hour duration storm event precipitation depth is 1.2 inches. The 100 -year frequency, 1 -hour duration storm event precipitation depth is 2.6 inches. The 100 -year frequency, 24 -hour duration storm event precipitation depth is 4.3 inches. Times of concentration were calculated using the methodology described in TR-55 (US Soil Conservation Service 1986) for sheet flow and shallow concentrated flow, and via Manning's equation for channel flow. HEC-HMS modeling software (US Army Corps of Engineers Hydrologic Engineering Center 2010) was used to determine the routing of surface runoff from the delineated drainage basins and the resulting estimated peak flows. Inflow hydrographs were routed through the detention pond as modeled in HEC- HMS to size the pond. i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. (704 !_ Golder Associates February 2016 Appendix B-3 7 1407882B Rev. 1 5.3 Hydraulic Criteria There are no manhole inlets or storm sewers on the Site. There are also no check dams or drop structures proposed as part of the drainage improvements. Surface water run-on (clean stormwater) is to be routed around the proposed Landfill using open channels, except where culverts are required under the new access road northwest of the entrance area, all designed for the 100 -year, 24 -hour storm event. Runoff from the Landfill will be collected in open channels on the Landfill, and conveyed via perimeter channels and culverts to the stormwater detention pond. The stormwater detention pond is designed to store the 100 -year, 1 -hour storm volume and release the water at a rate not to exceed the 5 -year, 1 -hour peak discharge rate from the pre -developed watershed. The pond was also designed to safely pass the 100 -year, 24 -hour peak flow rate above the 100 -year, 1 -hour storm volume while maintaining more than the required minimum 1 foot of freeboard. A stage -storage table/curve for the detention pond, including the storage capacity, peak (100 -year, 24 -hour) water storage elevation (WSE), and freeboard, is provided in Attachment B-3-1. The detention pond is designed with interior sideslopes at 4 horizontal to 1 vertical (4H:1V). A riprap outlet apron will provide permanent erosion protection at the downstream end of the pond outlet pipe before discharge onto natural ground. Peak flows, calculated using HEC-HMS as described in Section 5.2, were used to size channels (assuming normal depths), the stormwater detention pond and appurtenant structures. Culverts were sized using HY-8 culvert analysis software (FHWA 2014). Run-on flows will be diverted around the proposed Landfill and will be returned to sheet flow using a permanent riprap-lined dissipation basin in the northwest corner and a grass -lined dissipation basin in the southeast corner of the Facility. Flow within the east run-on diversion channel at the southeast corner of the Facility is at a sheet flow velocity and therefore does not required the riprap revetment in the dissipation basin. The surface water calculations for runoff and run-on controls can be found in Appendices B-3-1 and B-3-2, respectively. i:1•14 \1407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 8 1407882B Rev. 1 6.0 DRAINAGE FACILITY DESIGN 6,1 General Concept The proposed stormwater control concept for the Facility is to replicate historic drainage patterns as closely as possible. Run-on flows will be diverted around the proposed Landfill and returned to sheet flow. On -site runoff flows from the Landfill will be directed to the detention pond located adjacent to the southwest side of the Landfill and will be released at a rate not to exceed the 5 -year, 1 -hour peak discharge rate from the pre -developed watershed. Open channels to divert stormwater run-on from off -site upgradient areas are designed along the north and east perimeter of the Landfill. These channels will be 1.5 feet to 5.3 feet deep, with 3H:1V and 6H:1V sideslopes, and, at their respective discharge points, will return the channelized flows to sheet flow using energy dissipation structures to maintain discharge velocities below the design threshold for erosion. Run-on flow from off -site upgradient areas will not be allowed to mix with on -site stormwater runoff from the Landfill. The development of the Facility will not materially alter stormwater watershed basins or runoff drainage patterns in the nearby vicinity; thus the post -development runoff peak flows contributing to Jackson Draw are expected to be comparable to the existing pre -development conditions. The stormwater run-on flow and upgradient drainage basins were analyzed for the existing pre -development conditions, during the Landfill operations, and after the Landfill is closed (post -development). The proposed run-on control channels will route stormwater that currently occurs as sheet flow around the Landfill area and return it to sheet flow before reaching the Facility boundary. Since the site and surrounding area are situated within the extent of one or more broad alluvial fans and thus lack defined drainageways, the precise extent of stormwater that might be intercepted by the site is poorly defined. Runoff from the Landfill will be temporarily detained within the stormwater detention pond is projected to have a minimal overall effect on downstream flows. 6.2 Specific Details and Compliance with Weld County Code Drainage improvements for the Facility were designed in conformance with the Weld County Storm Drainage Criteria and the Urban Storm Drainage Criteria Manuals, Volumes 1, 2, and 3, including the Weld County Storm Drainage Criteria Addendum to the Urban Storm Drainage Criteria Manuals. Temporary and permanent surface water structures and erosion control measures will be constructed over the life of the Landfill to manage surface water runoff and contact water (i.e., stormwater runoff that has contacted exposed waste or waste having only daily cover). Design objectives for the surface water controls include: ■ Provide trafficable roads; i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 9 1407882B Rev. 1 • Prevent contact water runoff from leaving the active areas of the Landfill; • Dived surface water run-on from areas upgradient of the Landfill around the site; • Prevent run-on to the active area of the Landfill; and • Prevent discharge of contaminated stormwater from the Site. The basis of stormwater control design for the Facility is to replicate historic drainage patterns as closely as possible. Components of the surface water control system include: • run-on diversion channels; • a culvert crossing under the entrance road with a dissipation basin; • Landfill perimeter and access road channels; • a culvert crossing under the Landfill perimeter road discharging to the detention pond; • terrace channels; • downchute channels with stilling basins; and • a detention pond with an outlet pipe. In addition, there will be a small stormwater catchment basin southwest of the scalehouse to capture and release runoff from the entrance/infrastructure area. Drawing B -3-3B shows the locations of the proposed pem-ianent surface water control structures. Drawings B-3-4 through B-3-6 provide the details for these structures. 6.2.1 Temporary Surface Water Management Surface water will be managed through a series of temporary berms and/or channels that will divert run-on away from the active area and direct runoff toward temporary surface water ponds or the permanent stormwater detention pond. Surface water runoff that is not contact water will be managed via gravity drainage or pumping to the stormwater detention pond prior to release from the Site. Details for the temporary stormwater control structures and other best management practices (BMP's) will be provided to the CDPHE for informational purposes with the construction packages for each cell prior to construction. Any temporary surface water controls will be designed to handle a 25 -year, 24 -hour storm event. 6.2.2 Final Stormwater Management System Permanent drainage improvements for the Facility were designed in conformance with the Weld County Storm Drainage Criteria and the Urban Storm Drainage Criteria Manuals, Volumes 1, 2, and 3. 6.2.2.1 Run-on Diversion Run-on diversion channels were evaluated and include five trapezoidal open channels (Channels 0 through 4) along the north and east perimeter of the Landfill. The diversion channels will flow to the west and south to route stormwater run-on around the Landfill. These channels are designed to control the 100 -year frequency, 24 -hour duration storm event and include a minimum 1 foot of freeboard. A culvert i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 10 1407882B Rev. 1 crossing consisting of either four concrete box culverts or an equivalent single -span box culvert will be installed northwest of the scalehouse to convey stormwater from the north run-on diversion channel (Channels 0, 1, and 2) beneath the entrance road and into a dissipation basin. The dissipation basin, which will be lined with riprap, will be placed directly downstream of the culverts to spread and dissipate the flow prior to discharge as sheet flow onto natural topography. The dissipation basin has been designed to control the runoff from a 100 -year, 24 -hour storm event and reduce the discharge flow velocity to no greater than 4 feet per second. A similarly sized grass -lined dissipation basin will also be placed at the discharge point of the east run-on diversion channel. The run-on channels, entrance road culvert crossing, and dissipation basins will be constructed as shown in Drawing B-3-6. 6.2.2.2 Runoff Control Perimeter channels adjacent to the waste footprint (embedded within the perimeter berm), as well as downchute channels, terrace channels, and an access road channel, will be used to control runoff from intermediate- and final -covered areas of the Landfill. The locations of these features are shown in Drawing B -3-3B and details are provided in Drawings B-3-4 through B-3-6. All runoff control channels with design flow velocity greater than five (5) feet per second will be lined with either turf reinforcement mat (TRM) or riprap. All surface water runoff from disturbed areas is designed to be collected and report to the stormwater detention pond located directly west of the Landfill. The perimeter channels will be constructed in segments as the phased development of the Landfill advances and the perimeter berm is constructed. Perimeter channels will be grass -lined trapezoidal channels with 3H:1V side slopes, 10 -foot bottom widths, and 3 -foot depths. Perimeter channel reaches RL 6L and RL 7L are designed to be lined with riprap due to larger peak flow velocities and base -shear stresses. The terrace channels will be grass -lined "V" channels formed by the construction of a 15 -foot wide terrace situated at the approximate mid -point of the landfill sideslopes (approximately 50 feet vertically from the top and bottom of the approximate 100 -foot high Landfill sideslope). Across its width, the terrace will slope at 10H:1V inward toward the landfill, resulting in a channel depth of 1.5 feet; the opposite side of each terrace channel will slope at 4H:1V coincident with the final Landfill sideslope. The terrace channels will slope longitudinally at 1% across the final cover surface and converge at selected points on the final cover, where they will discharge into one of three reinforced downchute channels to carry the flow down the Landfill sideslopes. The access road channel will parallel the permanent access road that extends from the northwest corner of the Landfill to the top deck, and will consist of TRM-lined "V" -notch channels with sideslopes of 3H:1V and a depth of 1 foot. The downchute channels will be trapezoidal with 3H:1V sideslopes, 10- to 25 -foot bottom widths, and 1.5 -foot depths. At the base of the downchute channels, where the flow enters the perimeter channel, hydraulic stilling (jump) basins will be installed to dissipate hydraulic energy. The downchute channels and hydraulic stilling basins are designed to be constructed with riprap; however, articulated concrete i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 11 1407882B Rev. 1 block (or alternative material as approved by the Engineer) may be substituted at the time of construction to reduce future maintenance requirements. The perimeter channels will convey the stormwater around the perimeter of the Landfill to the stormwater detention pond. Stormwater will ultimately report to the stormwater detention pond via three 42 -inch diameter culverts to be installed beneath the perimeter road on the west side of the Landfill, as detailed in Drawing B-3-5. There will be approximately three feet of cover over the culverts to provide load -bearing capacity for the vehicular loads on the perimeter road. Perimeter channels and run-on diversion controls will be constructed as described elsewhere in the Engineering Design and Operations Plan (EDOP). Stormwater will be managed in accordance with the Colorado Discharge Permit System (CDPS) Stormwater Management Plan (SWMP) General Permit for "Stormwater Discharges Associated With Non Extractive Industrial Activities" (COR900000) (application for permit coverage to be submitted prior to commencing Landfill operations). 6.2.1 Erosion Potential Evaluation An evaluation of the effects of erosion due to rainfall on the proposed final cover was performed. The analysis involved using the Revised Universal Soil Loss Equation, Version 2 (RUSLE2) erosion modeling software (USDA 2010) to estimate the amount of soil loss caused by sheet and rill erosion of the final cover immediately after closure construction and after a 5 -year period of vegetative growth on the final cover. RUSLE2 calculations are presented in Appendix B-7 of the EDOP. Annual soil loss due to erosion in the first year of closure and long-term (i.e., after vegetative growth on the final cover) was predicted to be 2.8 tons/acre/year and 1.8 tons/acre/year, respectively, and less than the regulatory soil loss tolerance of 5 tons/acre/year for Landfill final cover slopes in surrounding states. i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates f 1407882B Rev. 1 CO N C CL) O Q February 2016 fil Open Channel Summary M m C) co H Maximum Normal Flow Depth(21 (ft) 4.3 in Ci1 CC7 N O . r O I` 0 0.75 NLOr VD ® N` O O LIDr a O OL-O N T- ---R OD O VD C\N s- L4 M O CD CO r Ln M o CO N CD CO r CD 0O CJ O E J W 'y 0 cv II) it M KIS M Co N N r- Ni a 4 co c"5 2.5 i cc N 3.5 o --)Co Lf7 4 5.7 4.6 N` cd LS7 M CJ N� N- M O)) N CO c 5.7 LC) 0 ET.) s _ t co C) . • � s ❑ ` _ 2 U CY"J Ln Ln C'i 3.6 1 Ln t- LO N O MC �a Lc O C`')06 CJ O C 1� CD M 3.0 CD C J CD M LO r O r- LC) r Ln r- Lf) r Lf) r LC) r- Bottom Width (ft) O 35 20 O r CD 0 r 0 0 0 0 0 0 CD O r 0 O O OL0 r O r V) CA r r r r r r Right Side Slope (H:1V) O Cfl O Cfl O C:5 O to © C") 3.0 Q O cn O M 3.0 O M O rvi C (- J O c'i O O J ( Q coo 4 c+i .' J O ti Left Side Slope (H:1 V) a ^ rJ Cr; O cry O M O CD C M O 4 CD Ci C7 C3 CD C6 CD Ce; C7 M Ca CN6 CD M® - C? M4 CD - 6 CD e3 C] e3 O M C D y C at 0:1O _C cn -- 0 in O O 0 I` p O 0 a r O o o r O a N— O 0 o 0 r O 0 0 r O 0 0 r 0 0 0 r 0 0 Ln co O 0 O r O o O O a a r O o O O o 0 r O a in (CD O o O r O o O r O 6 O Lo N o O Ln CJ C O to CJ o Design Peak Q100 (cfs) C3) in coin M M r r on LO co N LO N CO( O LO ti CO C+J • (~ CO d' ti CO s3- 70.8 70.6 Ll C() C') O IC r r N C1 CO Lo CO CO CO• 57.5 P-- r r Channel Lining TRM TRM TRM cn O Grass Grass Grass Grass Grass I- Grass (Q Grass Riprap to O H Grass J Grass a (G ± e a 2 ± a (2 ❑' Channel Designation Reach 0 r 0 tt C) Et N 0 CO C) cc) CJ CO N Reach 4 J J J J E' RL5 road (0J i RL7 RL7L RT2 road I— I— 0 ❑ DC N C ❑ _CO H C O Z C) r r_ r- 0 -o C a 0 Lri M O C� r_ co cr? C1) 015 -o r C Ct U r C C C) I- C) U d C r- 015 C) C 0 ail O) 0 C� C� Based on a C) C C C6 C-) a) C Q �I----� O C) 13 C C6 U) C) C C CD U C CD C) C U) Ct L Lf) M O O C U) 0) C C C (0 Based on a C\ i:11411407882h1040010403 ednp rev1lappendix b\app b -311407882b app b-3 drainage plan 19feb1&i.dncx February 2016 Appendix B-3 13 1407882B Rev. 1 Four 5 -foot by 5 -foot concrete box culverts, or a single -box culvert equivalent, will be placed in the north run-on diversion channel to facilitate a crossing for the proposed Site access road. These culverts have been sized to pass the design storm without overtopping the road. An alternate culvert crossing design and/or materials may be submitted at the time of construction as a substitute for the proposed concrete box culverts. This alternate design will provide the equivalent flow capacity to control the design storm event and will be subject to Weld County approval. The culverts will then discharge into a riprap-lined dissipation basin to spread the flow and reduce the velocity to less than 4 feet per second prior to discharge as sheet flow onto natural topography. The length of the riprap basin is designed as approximately 80 feet. The basin will be constructed of riprap with a 050 of 6 inches as calculated in the design. Stormwater released from the east run-on diversion channel (Channel 4) in the southeast corner of the Facility is calculated to have a design flow velocity equal to 4 feet per second, and therefore will be discharged as sheet flow directly onto the existing natural ground surface without the need for additional erosion controls. Detailed design information can be found in Appendix B-3-2. A stormwater detention pond will be constructed near the southwest corner of the Landfill to temporarily store on -site runoff from active areas of the Landfill. The stormwater detention pond is designed to capture the 100 -year frequency, 1 -hour duration storm event, and the water collected will be released over a period of approximately 40 hours. The proposed stormwater detention pond, shown in Drawing B -3-3B, has a total storage capacity (to the pond crest) of approximately 16 acre-feet, with 5.2 acre-feet of effective storage below the top of the outlet riser. Hydraulic modeling results show 2.5 feet of freeboard between the maximum predicted water surface and the pond crest. The interior sideslopes of the detention pond are designed at a 4H:1V slope. Detailed design information for the detention pond can be found in Appendix B-3-1. 6.2.2 Stormwater Controls Inspection and Maintenance Drainage improvements will be easily accessible for maintenance from the perimeter access road. This maintenance will include keeping the culverts, channels, and detention pond free of accumulated sediment and debris. Pawnee will be responsible for inspection and maintenance of all on -site drainage improvements. Inspections will take place at least quarterly during the operating life of the Landfill and following significant precipitation event(s) (i.e., equal to or exceeding 1.0 inch). Copies of the inspections shall be kept on file at the Site. A sample inspection log form can be found in the Operations Plan (Appendix C of the EDOP). i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 14 1407882B Rev. 1 7.0 CONCLUSIONS 7.1 Compliance with the Weld County Code This Drainage Report has been prepared in compliance with the criteria set forth by the Weld County Storm Drainage Criteria (Section 8, Article XI of the Weld County Code), Urban Storm Drainage Criteria Manuals (USDCM), Volumes 1, 2 and 3, and the Weld County Storm Drainage Criteria Addendum to the Urban Storm Drainage Criteria Manuals, Volumes 1, 2, and 3, dated October 2006. It is being submitted as part of the EDOP and as part of, and in support of, a Weld County Use by Special Review (USR) Permit Application for Pawnee Waste LLC for the Pawnee Waste E&P Landfill. 7.2 Drainage Concept The proposed Facility is located on agricultural land, and is not predicted to have any negative impacts on the properties located upstream or downstream. The Facility as designed will not adversely affect adjoining property owners. There are no existing structures that could be damaged by surface runoff immediately downstream from the property. i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. Golder Associates February 2016 Appendix B-3 15 1407882B Rev. 1 8.0 REFERENCES US Army Corps of Engineers Hydrologic Engineering Center. 2010. Hydrologic Modeling System (HEC-HMS). (3.5). Davis, California: US Army Corps of Engineers. August 10. US Federal Highway Administration (FHWA). 2014. HY8 — Culverts Version 7.30 FHWA Culvert Analysis May. Washington, D.C.: FHWA Office of Technology Applications. US National Oceanic and Atmospheric Administration (NOAA). 2013. Precipitation -Frequency Atlas of the United States, Atlas 14, Volume 8 Version 2.0: Midwestern States Silver Spring, MD: US Department of Commerce. US Soil Conservation Service. 1986. Urban Hydrology for Small Watersheds. Washington D.C.: United States Department of Agriculture. i:11411407882b1040010403 edop rev1\appendix b\app b -3\1407862b app b-3 drainage plan 19feb16.docx. (704 !_ Golder Associates DRAWINGS C I$M: WYd4C3UW01T1335 $Y4 k 30345 $.L IA? p45 E 000 A: rat 3 Jn 000 rinU.14.On S 111, VI 0 r k CO Lc m 0 J (n J cr O z a oQ Q Q Jtam _I it o Q W J ooI�a LLJ w0 ›- H le C/) Ill Ill Z cC fl' w D wza w CD w Q C ❑ zz cZ 0 fl PREPARED BY: C O M v co cts v O CO .O CO N O 00 O L O 0 U O O v S J LIST OF DRAWINGS Y. Z :r. s x J. x 3.3-2B S'ORLAWATER CCN-?OLS 'LAN R$A DETAILS (I CF 3; 0-3.5 DETAILS (2 CF 3: > 7 U =- y _ l^ u u r ≥ z i C x Y _ .. 1 ^. y i 7 x i 1 u -: ii I.1 x y _ '- or, I X It or uu S n i a`i n 0 j I'1 i 0 co o Tf 4 w u t O W w 4 J J oO O0 g 0. W U ea Q W F W° W U 13 W 3.a Le 0 a W W W dti ? W g �Gr CCISLILTANT c Q N uco u0 O a- n 0 L re 7 L 2 I\SUr7 �:7K ::I:,•?Ht• 1 -OOP SUS A''RDVEC J LI 2 0 u 0! "YY"-1111-3D CC3CRIP-ICN f, b LC caw I0050f$30.Maas; OP! 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Y ?o G • 7 7 2 ISSUED °R CC'HE EDOP SL3MITTAL m 0M)0) x33310, :CWCV Gj ;x001/ a0: -Ica La+:+. yosD.ac33d:nt)11'l1:axoartle3ct.-:. .. :e APPENDIX B-3-1 SURFACE WATER RUNOFF CONTROLS CALCULATION � Golder Associates CALCULATIONS Date: Project No.: Site Name: Subject: February 19, 2016 1407882B Rev. 1 Pawnee Waste E&P Landfill Weld County, Colorado APPENDIX B-3-1: SURFACE WATER RUNOFF CONTROLS CALCULATION Made by: MBR Checked by: CPB 6,a -(-.?b Reviewed by: MAY 5 f1L. 1.0 OBJECTIVE Design the locations and geometry of perimeter channels, terrace channels, downchutes, culverts, and a. stormwater detention pond needed to convey and detain stormwater runoff from the Pawnee Waste E&P Landfill (Landfill). 2.0 METHODOLOGY Drainage basins (watershed areas) for the proposed surface water control system were delineated based on proposed top of final cover grading plan for the Landfill, as shown in Drawing 8-3-3A. The stormwater controls plan for the completed Landfill is shown in Drawing 8-3-28, The drainage basin (watershed area) for the pre -development condition is shown in Drawing 8-3-2. Times of concentration were calculated using the methodology described in TR-55 (US Soil Conservation Service 1986) for sheet flow and shallow concentrated flow, and Manning's equation for channel flow. HEC-HMS modeling software (US Army Corps of Engineers Hydrologic Engineering Center 2010) was used to determine the routing of surface runoff from the delineated drainage basins and the resulting estimated peak flows. Peak flows were used to size channels, assuming normal depths. Culverts were sized for the peak flow using HY-8 culvert analysis software (FHWA 2014). 3.0 ASSUMPTIONS I The Landfill area is approximately 74 acres, with the detention pond which adds an additional 2.4 acres. • Design storm event depths used in this study are from NOAA Atlas 14 (NOAA 2013), included as Attachment B-3-1-1 and are summarized in the following table: Storm Event a Depth (in) 2 -year, 24 -hour 1.82 5 -year, 1 -hour • 1.22 100 -year, 1 -hour 2.63 100 -year, 24 -hour 4.30 IN The design storm is distributed in time using a USSR dimensionless s -graph for the Great Plains (USSR 1992). • Lag time is equal to 60% of the time of concentration, i:\1411407882b1040010403 edop rev ltappenthx blapp b -3\1407882b app b-3-1 surface water 19feb16.docx Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, Colorado 80228 Tel: (303) 980-0540 Fax: (303) 985-2080 www.golder..com Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation CALCULATIONS Paae2of4 Project No.: 1407882B Rev. 1 Made by: MBR Site Name: Pawnee Waste Checked by: CPB fop_ Le 5 Date: February 19, 2016 _ Reviewed by: MAY 1 C Art_ irl A y • The maximum sheet flow length is 300 feet for the pre -development condition and 100 feet for the landfill. • The minimum lag time is 3.0 minutes (a time of concentration of 5 minutes per TR-55). • An SCS curve number of 74 for the landfill was selected to reflect "Good" coverage of "Pasture, Grassland, or Range" with a Hydrologic Soil Group (HSG) of C. ■ A composite SCS curve number for the pre -development basin was estimated reflecting "Good" coverage of "Pasture, Grassland, or Range" with varying Hydrologic Soil Group (HSG) classifications. HSG values were determined from a soil map (NRCS 2014), included as Attachment B-3-1-2. • Manning's roughness coefficients of 0.035 (for design capacity) and 0.030 (for design velocity) were assumed for both grass -lined and turf -reinforcement mat (TRM)-lined channels. ■ Perimeter channels were designed with a minimum one foot of freeboard. • Culverts beneath the west perimeter access road (leading to the detention pond) were assumed to be corrugated metal pipes (CMP), placed at 1.8% slope with projecting entrances for conservatism (actual constructed culverts should have mitered ends to conform to slope). • All runoff control channels with design flow velocity greater than five feet per second are to be lined with either TRM or riprap. 4.0 CALCULATIONS Channel reach locations and basin delineations are identified in Drawings B-3-2, 8-3-3A, and B -3-3B. Hydrologic parameters for the basins (Tables B-3-1-1 and B-3-1-2), lag times (Tables B-3-1-3 and B-3-1- 4) and reaches were entered into the HEC-HMS modeling software and routed to calculate peak flows for each basin and channel (Tables B-3-1-5 and 8-3-1-6). Channels were sized for the landfill to accommodate the peak flow (Table B-3-1-7). Riprap lining for the downchute channels was sized for the peak flow and is shown in Table B-3-1-8. Riprap-lined stilling basins will be placed at the downstream toe of the downchutes; the sizing of the stilling basins is shown in Table B-3-1-9. Output from the HEC-HMS model and the HY-8 model are attached. The HEC-HMS model inputs and output are included as Attachment 8-3-1-3; the HY-8 model output is included as Attachment B-3-1-4. 5.0 RESULTS/CONCLUSIONS Individual channel reach data is summarized in Table B-3-1-7, with peak flows, depths, and velocities associated with the design storm event. Perimeter channel reaches L1, L3, L4, L6, and L7 are grass- lined trapezoidal channels. The access road channel reaches T2 and L5 should be lined with TRM. All downchute channels, as well as Reaches L7L and L6L (adjacent to the culvert inlets for the west perimeter road culvert crossing), are to be lined with riprap. i:1.14114078$2bk040010403 estop reullappenGix bxapp b-3\1407B82b app b-3-1 surface water 19feb10.dacx Golder Associates CALCULATIONS Pane 3 of 4 Project No.: 1407882B Rev. 1 Made by: MBR Site Name: Pawnee Waste Checked by: CPB 44,._ ce l Date: February 19, 2016 Reviewed by: MAY y Three 3.5 -foot diameter CMP culverts will be constructed at the low point in the perimeter channel, near the southwest corner of the landfill, to convey stormwater beneath the west perimeter access road and into the detention pond. These culverts have been sized to pass the design storm (100-year,24-hour) without overtopping the road (Attachment B-3-1-4). An alternate culvert crossing design and/or materials may be submitted at the time of construction as a substitute for the proposed CMP culverts. This alternate design will provide the equivalent hydraulic performance (i.e., flow capacity) to control the design storm (100-year,24-hour) and will be subject to Weld County and CDPHE approval. The detention pond was sized to temporarily store the 100 -year, 1 -hour storm volume of 5.2 ac -ft (as calculated in Table B-3-1-1) and release this volume over a period of 40 hours at a rate not to exceed the 5 -year, 1 -hour pre - development peak flow rate of 3.1 cfs, through a 3 -foot diameter perforated outlet riser pipe, see Attachment B-3-1-3. The riser pipe will have an open top with a galvanized welded wire or rebar trash rack plate which will act as an emergency spillway and it is designed to pass the 100 -year, 24 -hour peak flow event with a full pond and maintain 2.5 feet of freeboard between the design stormwater surface elevation and the embankment crest. See Figure B-3-1-1, below. I 5,077 5,076 5,075 5,074 5,0.73 5,072 5.071 5,070 5,069 5,068 5,067 fl 0.5 J Area (ac) 1.5 ? 7.5 i5,077 3 d 3 0 ce nu -,---- - - i nd Crest 5.075 5076 ft. 5.075 5,074 Peak El. 5073.5 WSE ft. f ¢� T 5,073 C 5,072 retei -- -- 5,071 \ \ .. Ris rTst 071 ft. .„.... .. - 5,070 El. CM El? ._ _ .. .._ _ ------.----------- 5,069 5.068 Et Es 05 — 00 2.0 4 0 E.. O ID CO - 60 8.0 10.0 Storage (eat) 17.0 14.0 16.0 18.0 5.067 Figure B-3-1-1 Detention Pond Elevation vs. Storage Capacity and Elevation vs. Area • • • i:114U1407882b1040010403 edop revi%appendix b.app tn-3%1407882b app b-3-1 surface water 19feb16.docx Golder Associates CALCULATIONS Paae4of4 Project No.: 1407882B Rev. 1 Made by: MBR Site Name: Pawnee Waste Checked by: CPB c ate Date: February 19, 2016 Reviewed by: MAY 3 'k. 11A1 6.0 REFERENCES US Burearu of Reclamation (USBR). 1992. Flood Hydrology Manual. Bureau Of Reclamation. Washington D.C.: United States Government Printing Office. US National Oceanic and Atmospheric Administration (NOAA). 2013. Precipitation -Frequency Atlas of the United States, Atlas 14, Volume 8, Version 2.0: Midwestern States Silver Spring, MD: US Department of Commerce. US Soil Conservation Service. 1986. Urban Hydrology for Small Watersheds. Washington D.C.: United States Department of Agriculture. US Army Corps of Engineers Hydrologic Engineering Center. 2010. Hydrologic Modeling System (HEC-HMS). (3.5). Davis, California: US Army Corps of Engineers. August 10. • US Federal Highway Administration (FHWA). 2014. HY8 - Culverts Version 7.30 FHWA Culvert Analysis May. Washington, D.C.: FHWA Office of Technology Applications. • • 1114\1407882b4040010403 edop revertappendix blapp b-3t1407682b app b-3-1 surface water 19feb16.docx Golder Associates TABLES W J CO r t „ter Q t 12 m2 LU CO CO Q Z to CO CO Pawnee Waste O 1• r ti = CO M aY Y Apprvd: 0 'Z. E&P Landfill Project Number: 1407882B ISOM 100 -Year Recurrence Interval E L OA C cn y 4) 0 M CO N 100-yr, 1 -hr Unit Runoff Runoff Runoff Q Volume Volume (in) (ac -ft) (ft) 0.68 0.86 37,576 0.68 0.40 17.491 ,C' co O CO CD M 0O cp co co 0 0 dot+ 7 �6'ui CO r CO N 0O co (D CO 0 0 MT- O <0(6�ui CO 'Yt M g to co t0 CO 0 0 Col) t O CO M oo co (O <) 0 0 0.68 0.39 17.094 1.99 0.64 27,793 m :O N N <'7 N 100-yr, 24 -hr Unit Runoff Runoff Runoff Q Volume Volume (in) (ac -ft) (ft'') 1.82 2.30 100.163 1.82 1.07 46,625 (.Oc cm ti ti id Tt WD r r N N C°. gr 1.82 1.80 78,518 1.82 0.57 24,947 1.82 0.94 40,867 1.82 0.37 16,037 1.82 0.39 17,205 1.82 0.95 41,221 1.82 1.05 45,566 3.62 1.16 50.445 N s+] c. co Lo O5 el r - Cl O II U) O 2 �U r r U: C_b MM r r U) L') el el r U: i-1.) MMMMMMN)O r r U) Lb r r l; C_7 iri CO Composite SCS Curve No. CN=74 CN=74 CN=74 CN=74 CN=74 CN=74 CN=74 CN=74 CN=74 CN=74 CN=74 CN=94 0) II z 0 Pond Area (acres) CO as r- 1:7; If Z 0 Bare Soil HSG C (acres) (O CS). r CN=74 Pasture, Grassland, or Range HSG C Good Cond. (acres) O LE? te-<D-M(QNI<V U)0) 21 co �N..0)Tr(OUNda`s co cc; Subbasin Area (sq mile) N— O Mr N r 0 O 66 0.0180 0.0108 CO CM CQ C_74)M r O 0 0 O66C N— CA O O 0 0 Ir P� vct O O O 0 0 6Ci 0.0108 0.0060 M v- 6 Subbasin Area (acres) to cO in �� c) cm el <Ci al co y- MsQn!(V r (O N cc; ) Co cm LQKi O7 Subbasin Area (N2) 660474.289 307445.919 500786.978 301803.068 517747.808 164498.562 269478.794 105747.77 113451.127 271812.787 r 300463.323 167281.092 N t� O 00 to o a (15 0 F- H F- H J J J J J J J CL CO C) I— I \1411407882810=0010402 [COP FNL'Appendix B1App B-3\B-3-1\Landfill cover hydra ogy.xlsm TABLE B-3-1-2 PRE -DEVELOPMENT SUBBASIN SUMMARY TABLE Pawnee Waste to r r cr m Date: m Y cc Apprvd: U i O �F+ • M Q Q CO 00 C ,-- O O ` Q r O s: E 33 (v IILAA Ev/ C 6 Z = 15 a 0 O 13 ca 3 5 -Year Recurrence Interval t W ❑ W ft O r v Storm Duration N N cq A S = 1000 - Unit Runoff Runoff Runoff 10 Q Volume Volume CN (in) (ac -ft) (ft 3) 0 op tp 0 - LO cr.;:r• N M Q a N '47 0) co to 0 r tb N Composite SCS Curve No. 0L=ND CN = 80 Pasture, Grassland, or Range HSG D Good Cond. (acres) (O N- -4: CD T- CN=74 Pasture, Grassland, or Range HSG C Good Cond. (acres) 492.43 CN=61 Pasture, Grassland, or Range HSG B Good Cond. (acres) (.0 O) N It) co CN=39 Pasture, Grassland, or Range HSG A Good Cond. (acres) a) a ci c.) Subbasin Area (sq mile) n et t o x- CA co. Subbasin Area (acres) -o- CO Gi6i co Q r t CC) co 0 . C 40 05 a Q v Cn O) N' Co N Li 45,286,879 d ro Ca _ C E o 713 7 a - it U I - I.'\1411407882B1040010402 EDOP FNLWppendix BWpp B-31B-3-11Landrill Pre -development hydrolory.xlsm TABLE B-3-1-3 BASIN TIME OF CONCENTRATION CALCULATIONS LO r V DC N- m t'a G m Y s C.) Apprvd: CO N CO CO t- git Project Number: Flow Segment 2 Typical Hydraulic Radius Travel Slope (Channel Only) Time (tUft) Roughness Condition`'(ft) (min) 0.04 U Unpaved 0.7 0.04 U Unpaved 0.7 0.04 U Unpaved 0.6 0.04 U Unpaved 1.3 0.25 U Unpaved 0.2 0.04 U Unpaved 0.5 I 0.25 U Unpaved 0.2 I 0.25 U Unpaved 0.2 I` C- M 7.2 rJ Sheet I 100 0.25 I E I Short Grass J I 4.7 'Shallow 120 I 0.25 U Unpaved 0.2 6) CO O aY C6 aO. V W c :D O O in N 6 Type of Length Flow (ft) Shallow 135 Shallow 135 Shallow 110 Shallow 245 Shallow 100 Shallow 105 O 6 0 6 To to Shallow 110 Channel 500 Shallow 145 Flow Segment 1 Travel Time (min) co co co cot-- oot� N- N- ti ypica y rau is Radius (Channel Only) (ft) Roughness Condition`l) Short Grass Short Grass Short Grass Short Grass Short Grass Short Grass Short Grass Short Grass Short Grass Short Grass W W W W W W W W W W Length Slope (ft) (ft/ft) V' 0 0 0 Tt Q Tt lb 0 0 0 CV 0 0 0 0 0 0 0 0 tt O 0 0 lb N 0 a Li) N 0 0 IC) N 0 0 In N 0 0 Type of Flow a) S Sheet Sheet Sheet Sheet 4)w L L Sheet 445 D4) S L Total Travel Time (min) u) IX) y- n f Cr) C N 'xi in,-: •- a- a- N r w co .- v N-- N 'D co y- MO T- In V M o 1- ; (O CD O "Zr co - 6 i i a (xi 3D n F- - v a r 6 o CO LO CC: t� �l C� n c0 to ,r - O o O N C7 N r I r-- 7 0 O CO L7 7 0 cO ti M r o CO ri 0D O O O) CO N 7 Cj N 0 O M lb In 7 0 o o Subbasin Area Composite Subbasin ID (sq mile) Curve Number Qt`+ N- O 0 F- T2 0.0110 74 T3 0.0180 74 T4 0.0108 74 L1 0.0186 74 LO a 0 J t`-- 0 ca 0 co I� CO a 0 J cr Q 0 J N- 0 0 0 J IL7 0.0108 74 Pd 0.0060 94 I:\14\1407882BU}400\0402 EDOP FNL\Appendix B',App B -3\B -3 -'\Landfill weer hydrology.xism TABLE B-3-1-3 BASIN TIME OF CONCENTRATION CALCULATIONS In r `7 ti cc m 6 W O T Ca 'a L U Apprvd: CO N CO CO O 11 Project Number: How Segment 4 > c c 002 H E t0 t+ N d r,. a N cfl Channel 1395 0.01 R Riprap 0.47 10.4 I Lag Time for subbasin Pd is the assumed minimum of 3 minutes. Typical Hydraulic Radius (Channel Only) (ft) tp in 0 VD 0 <t co 0 0 c� 0 Slope (ftlft) Roughness Conditional` a c r 0.010 E Earth -lined 0.010 E Earth -lined 0.010 E Earth -lined W 0 CD O r -. J 0 0 to N 0 3 a° r c m 0 c Ti.) co a 0 0 c m 0 How Segment 3 Travel Time (min) d cdiac;2oa6r: o tv d et . r a co to w Typical Hydraulic Radius (Channel Only) Roughness Condition''' (ft) I Unpaved Riprap 0.50 Unpaved Unpaved Riprap 0.57 Unpaved In 0 CO N 0 co 0 a C a crci a t6 I- a t6 2 Length Slope (ft) (ft/it) tp N o W r rs, Ls, Li, r C7 N N C 6 0 0 0 th Oho 00Ncox,ti 03 r r 47 N o tl r r C7 O L7 Tom r 0 G r CJ ❑i 0 Type of Flow O �_ to L (1) Channel Shallow Shallow Channel Shallow Channel c r co .c O c c co O — Subbasin Area Composite Subbasin ID (sq mile) Curve Number Q N- N 0 a F- T2 0.0110 74 T3 0.0180 74 T4 0.0108 74 L1 0.0186 74 N-- aDr- 0 Q 0006aoa J N-- 0 O co N+N+� corn— 0 O J 0 O J 0 O J MCA,) 000 �r 0 CD O J CI I:\14\1407882BU}400\0442 EDOP FNL\Appendix E1App B -3`,B -3 -'\Landfill weer hydrology.xlsm TABLE B-3-1-4 tn r Zr- cc f.-. 2 Date: D. Chkd: Apprvd: CO co N co C Project Number: Flow Segment 2 Travel Time (min) m d Typical Hydraulic Radius (Channel Only) Roughness Condition` i (ft) 'Unpaved D O r Type of Length Flow (ft) Shallow 330 Flow Segment 1 O 0 rev 13.4 ypica y rau is Radius (Channel Only) (ft) Roughness Condition'' Short Grass Ili Length Slope (ft) (ft/ft) r••• CO O O M 0 3 II) o H Sheet Total Travel Time (min) 0 U) Subbasin Area Composite Subbasin ID (sq mile) Curve Number Pre -development 1.6244 70 I:114114078a2E`d?40O,0402 EDOP FNL\App endlx E‘App B-3\E-3-11Landfill Pie -development hydroloay.xlsm TABLE B-3-1-4 1O r 1 C r rz m M Date: Ca Y s Apprvd: O co N co C Project Number: Flow Segment 4 Typical Hydraulic Radius Travel Slope (Channel Only) Time (ft/f1) Roughness Condition`'(ft) (min) a T Yi cv M q r D 0 C L co w N r J a Type of Length Flow (ft) Channel 114UU Flow Segment 3 Travel Time (min) III r ypica y rau is Radius (Channel Only) (ft) M L7 r Roughness Condition`' Earth -lined w Length Slope (ft) (ft/ft) O 0 0 0 0 0 co xi Type of Flow 0 C C iro O Subbasin Area Composite Subbasin ID (sq mile) Curve Number Pre -development 1.6244 70 I:1141140788?E`d?40O,0402 EDOP FNL\App endlx E‘App B-3\E-3-11Landfill Pie -development hydroloay.xlsm TABLE B-3-1-5 FLOW RESULTS FROM HEC-HMS Pawnee Waste E&P Landfill Project Number: 1407882B HEC-HMS Basin Model: HEC-HMS Met. Model: HEC-HMS Control Specs: Date: 7/14/15 By: MBR Chkd: Apprvd: Pawnee Landfill GP S -Graph 100-yr, 24 -hr 48 -hr, 1 -min Hydrologic Element Drainage Area (sq mile) Peak Discharge (cis) Time of Peak Total Volume (ac -ft) T1 0.024 33.5 06Jun2525, 01:03 2.4 L1 0.019 25.2 06Jun2525, 01:04 1.9 J -T1 -L1 0.042 58.7 06Jun2525, 01:03 4.3 R -L7 0.042 58.3 06Jun2525, 01:07 4.3 L7 0.011 16.7 06Jun2525, 01:01 1.1 J -L7 0.053 70.6 06Jun2525, 01:06 5.4 T3 0.018 26 06Jun2525, 01:02 1.8 T2 0.011 17.8 06Jun2525, 01:00 1.1 R -T3 0.011 17.7 06Jun2525, 01:06 1.1 J -T2 -T3 0.029 42.1 06Jun2525, 01:04 2.9 T4 0.011 16.3 06Jun2525, 01:02 1.1 J -T3 -T4 0.040 57.5 06Jun2525, 01:04 4 L3 0.010 15 06Jun2525, 01:01 1 L2 0.006 8.7 06Jun2525, 01:02 0.6 J -L2 -L3 0.016 23.6 06Jun2525, 01:01 1.6 R -L4 0.016 23.4 06Jun2525, 01:04 1.6 L4 0.004 6.1 06Jun2525, 01:00 0.4 J -L4 0.019 28.7 06Jun2525, 01:04 2 R -L5 0.019 28.7 06Jun2525, 01:04 2 L5 0.004 7.9 06Jun2525, 00:57 0.4 J -L5 0.024 33.1 06Jun2525, 01:03 2.4 R -L6 0.024 32.8 06Jun2525, 01:07 2.4 L6 0.010 16 06Jun2525, 01:00 1 J -L6 0.033 43.7 06Jun2525, 01:05 3.4 J -T3 0.126 169.9 06Jun2525, 01:05 12.7 Pd 0.006 21.3 06Jun2525, 00:55 1.2 Pond 0.132 59.3 06Jun2525, 01:24 15.8 Sink -Pond 0.132 59.3 06Jun2525, 01:24 15.8 Page 1 of 1 Golder Associates I:11411407882B\0400\0402 EDOP FNL\Appendix B\App B-3\B-3-1\Landfill cover hydrology.xlsm 7/22/2015 TABLE B-3-1-6 FLOW RESULTS FROM HEC-HMS PRE -DEVELOPMENT CONDITION Pawnee Waste Landfill Pre -development condition Project Number: 1407882B HEC-HMS Basin Model: HEC-HMS Met. Model: HEC-HMS Control Specs: Date: 7/14/15 By: MBR Chkd: Apprvd: Pre -development 5-yr, 1 -hr 48 -hr, 1 -min Hydrologic Element Drainage Area (sq mile) Peak Discharge (cfs) Time of Peak Total Volume (ac -ft) Pre -development 1.624 3.1 06Jun2525, 04:26 2.5 Sink -Pond 1.624 3.1 06Jun2525, 04:26 2.5 Page 1 of 1 Golder Associates I:11411407882B\040010402 EDOP FNL1Appendix B\App B-3\B-3-1\Landfill Pre -development hydrology.xlsm 7/22/2015 V) OV 03 I CO •� _N E L _a -O CZ 1- 2 cu a a Ct U Lf) r M1" It on S N ird C M5, W ii U L I- Q Q Pawnee Waste E&P Landfill m N 00 00 f• C T PROJECT NO.: Channel Roughness Parameters Mannings 'n' for Stability (Velocity Calculation) CD C' M CD CD O O d C) d G ✓ O ♦ fl D c7 o 6 'J C • CO d G U) CD M') O Q 6 O Ln CO d G O C' M M 0 CD 6 O O r) 0 G G Ln (Y% M 0 CD O O Ln CO d G LLD r) d G Mannings 'n' for Capacity (Depth Calculation) Li) Lf) 03 M o C' O O Li) C) 0 G Li) LI) c> Cl) 0 C' O J Lf) C) O G o in M O G O J o 't O G Ln L() 0) M) O O Q 6 U) (0 C' G U) o c> t 0 C' O O 0 't O G 0 't C7 G Design Channel Lining Grass -lined Grass -lined Grass -lined Grass -lined Turf Reinf. 1D C) C - Ji tit L_ Riprap Grass -lined a it L a_ CC Grass -lined Turf Reinf. Grass -lined Grass -lined Riprap a Cri CI CC a CZ CI CC rR II�� V O j(11'�'� V n O H ((9''� 0 (/��/ C O /�C C I� ��" O 1 O 1''� rn �/ 0 LL /�/ LL /y 11 Channel Design Geometry Minimum Channel Depth (ft) C> U) C') T 0 CO 0 CD 01 r O M O CD C}) M O l''J L) G T T Ln T U) U) T T Lt) T Lf) T C .y 3 C CO a '.--- G Q O O Q O 0 0 O O C, cD r, to O 25 W -C c al P cL . o<>0aCD00CD0oCDa c) C'' Cc) c^ C) ri c') C) M-- CV) •0 em M M Approximate Left Channel Bed Side Length Slope Slope (ft) (ft/ft) (H:1V) 2485 0.010 3.0 1085 0.010 4.0 _ G• c0 O r O O G r 0)r- r G O c ; C) O Ln r (Co O O O O O U) co I` W O CD O r O O r ^ 1371 0.040 3.0 1371 0.010 3.0 O r+i 0 O O r h- 00G 1870 0.010 10.0 845 0.065 3.0 1620 0.010 4.0 910 0.010 10.0 - 215 0.250 3.0 G r*j O N O 0 CD N G• r3 O N O 0 r) N Q100 from HEC HMS HEC-HMS Element ID Reach Designation (cfs) for Q IR L1 25.2 L1 RL2 8.7 L2 Co J R L4 28.7 J -L4 RL5 road 7.9 L5 CO J RL6L 43.7 J -L6 RL7 70.6 J -L7 RL7L 70.6 J -L7 RT1 33.5 T1 RT2 road 17.8 T2 CO H T NI RT4 16.3 T4 DC S 33.5- T1 CV J I DC W 57.5 J -T3 -T4 o 6 r- CO r (NNcd h- () J Lt CO J Et M Lt r, 0 Golder Associates I:\\1411407882B1040010402 EDOP FPJL`.Appendix BV1pp B-3\B-3-11Landfill cover hydrology.xlsrn W C .9 a U co M P m w fl I- _ C C Ct �t V tO r MBR ;7".: r 11 0 m Z V C- Q C CO N CO CO itt O 0 1.0 Q) u oZi a w Channel Evaluations I Available Freeboard (ft) C —LIa N O tV 2.2 0.3 000COrCO0rL)N (NI N , CV Ca O O CS MN ,- Hydraulic Calculations Top Width of Channel (ft) 0 0 cp r N N 0 CO N 0 0 06 • N 0 Cp N C7 0 co to N N 0 CO N C5 0 r • N 0. r N 21.0 24.0 0 ti r 0 4 CO Top Width of Flow (ft) NU7r `7 O r Cr) r 14.5 4.3 M-NV)toSy,coCiMh0')h to r et h r r to r h try r a) r M (46C? r r r 6r N Stream Power (W/m2) 00000 O co n- 23.50 245.5 N �t• Ch r CO C6r • - CO O N• 39.02 407.9 0 tfa 24.9 520.4 204.2 tO 6 t Normal Depth Shear Stress (Ibift2) ct h 'Ct 000 N CO r 0.47 2.87 r 0.60 COCOCOCOOLbthMCD h: h r 0N0N)00 N O CO u7 Ch 4 N 4.42 0a i- 4) 'a.O 7 E 2 z W MLfl6)�Nt h h aoodr6T- h- h h CO toaa>C3>rtoCO(5)CO CO CO araraat‘i(vc'i ttt h CO CO h O CD Cn Maximum Normal Flow Depth (ft) 0 11) Ps-- h O O N tf?h- O W r h- 6 6 tf) Cnh O 0 d' N 0 r r [FAN 0 Ct? CU O>t7t3>N r 0 CO r tta CO 0 0 CD rrV 6 CO 0 Maximum Velocity (ft/sec) (-,toco 6S N N 3.5 5.9 0i`-cl>h 4 t.7 d' CD I 3.5 7.2 h0)Mhto M N 0 vi CO Q100 from HEC-HMS Reach Designation (cfs) N h in o N C7 r IL4 28.7 RL5 road 7.9 h- ct h Co d' h C4 h IRT1 33.5 RT2 road 17.8 r ci RT4 16.3 DC 5 33.5 h IDC W 57.5 r N J J Ce � CO J re GO Ci —J - J re d J J IY CI I- Ce Z U o 1:\1411407882B10400\0402 EDOP FNLAAppendix B1App B-3\B-3-1'\Landfill cover hydrology.xlsin Table B-3-1-8 US Army Corps of Engineers (Steep) Method Riprap Size Calculation Riprap Channel Evaluation Pawnee Landfill PROJECT NO.: 1407882B Date: 7/14115 By: MBR Chkd: Apprvd: Reach Designation USACE Method Riprap Calculations for Steep Riprap (Bed Slopes >2% but <20%) Design Flow Q (cfs) Normal Flow Depth d (ft) Flow Unit Flow Concentration (ft2/sec) Factor Calculated Particle Size D30 (ft) Riprap Size D50 (inches) DC S 33.5 0.26 2.12 1.25 0.54 8.5 DC N 8.7 0.15 0.83 1.25 0.29 4.6 DC E 57.5 0.26 2.23 1.25 0.56 8.8 USAGE Paper EM 1110-2-1601, 6/30/94 1.95 So D= - nuts below as aeterminea m civi i i'10-2-1601, 6/30/94 Cg: Gradation Coefficient (D85/Di5) Riprap D50 determined as recommended in EM 1110-2-1601, 6/30/94 1.25 c D15 ) Flow Concentration Factor (1.25 from USACE steep riprap method) Page 1 of1 Golder Associates 1:11411407882B1040010402 EDOP FNL\Appendix B\App B-31B-3-1\Landfiill Cover Riprap.xlsm 7/22/2015 Table B-3.1-9 Stilling Basin Calculation If, r zi 7. t.- co co g6 a L V :pAJddb CO N Co CO O of v- • 0 • Z • c V °' mc w J =• a0 (t$ * cc awa. Hydraulic Calculations Minimum Length of Jump (ft) t* fq 0) M la O N G "CI ...0 N NO M't N Maximum Normal Normal Maximum Flow Depth with Conjugate Velocity Depth Velocity 'n' Froude Depth (ftlsec) (ft) (ft) Number (ft) 8.3 0.28 0.26 2.96 0.93 5.7 0.16 0.15 2.69 0.48 8.5 0.28 0.26 2.98 0.96 — Channel Configuration Mann ings 'n' Man ni ngs 'n' for Capacity for Stability (Depth (Velocity Calculation) Calculation) 0.040 0.035 L') 0 O O O O 0 Lt) M O O O O O Maximum Channel Depth (ft) Li r L') r U) ,- Right Side Bottom Slope Width (ft) '4 r CD M a r VM M g) ,.-g oM • I Left Side Slope (H:1 V) 0aa M M M Bed Slope N N Q N C O) ^ a�i it ca L.r) M I, cta to Reach Designation Or) v0 0 Z 0 IDC Length of Jump as a Function of Froude Number and Ratio to Conjugate Depth (d2) c, O O O m L'J 't oi1e21 ZPIi C7 O r N O Froude Number Golder Associates 1:11411407882B1040010402 EDOP FNL\Appendix B\App B-3\B-3-11Landfill cover hydrology.xlsm ATTACHMENT B-3-1-1 4/7/2015 Precipitation Frequency Data Server NOAA Atlas 14, Volume 8, Version 2 Location name: Grover, Colorado, US* Latitude: 40.8395°, Longitude: -104.1474° Elevation: 5080 ft* *source: Google Maps POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Deborah Martin, Sandra Pavlovic, Ishani Roy, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Michael Yekta, Geoffery Bonnin NOAA, National Weather Service, Silver Spring, Maryland PF tabular I PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Average recurrence interval (years) Duration 1 2 5 10 25 50 100 200 500 1000 5 -min 0.258 (0.202-0.330) 0.315 (0.247-0.404) 0.417 (0.325-0.536) 0.509 (0.395-0.657) 0.648 (0.489-0.875) 0.763 (0.561-1.04) 0.886 (0.628-1.23) 1.02 (0.692-1.45) 1.21 (0.788-1.76) 1.36 (0.860-2.00) 10 -mm 0.378 (0.296-0.484) 0.462 (0.361-0.592) 0.611 (0.476-0.785) 0.746 (0.578-0.963) 0.948 (0.716-1.28) 1.12 (0.821-1.52) 1.30 (0.920-1.81) 1.49 (1.01-2.13) 1.77 (1.15-2.58) 1.99 (1.26.2.92) 15 -min 0.461 (0.360-0.590) 0.563 (0.440-0.722) 0.745 (0.580-0.958) 0.910 (0.705-1.17) 1.16 (0.873-1.56) 1.36 (1.00-1.86) 1.58 (1.12-2.20) 1.82 (1.24-2.60) 2.15 (1.41-3.15) 2.42 (1.53-3.57) 30 -min 0.614 (0.481-0.787) 0.753 (0.588-0.965) 0.998 (0.777-1.28) 1.22 (0.943-1.57) 1.55 (1.17-2.09) 1.82 (1.34-2.48) 2.11 (1.50-2.94) 2.42 (1.64-3.45) 2.86 (1.87-4.18) 3.21 (2.04-4.73) 60 -min 0.754 (0.590-0.966) 0.921 (0.720-1.18) 1.22 (0.951-1.57) 1.49 (1.16-1.93) 1.91 (1.44-2.58) 2.25 (1.66-3.08) 2.63 (1.86-3.66) 3.03 (2.06-4.32) 3.60 (2.35-5.26) 4.06 (2.57-5.97) 2 -hr 0.894 (0.707-1.13) 1.09 (0.861-1.38) 1.45 (1.14-1.84) 1.77 (1.39-2.26) 2.27 (1.74-3.04) 2.69 (2.00-3.63) 3.14 (2.25-4.33) 3.63 (2.50-5.13) 4.34 (2.87-6.27) 4.91 (3.15-7.13) 3 -hr 0.974 (0.775-1.23) 1.18 (0.937-1.49) 1.55 (1.23-1.96) 1.91 (1.50-2.42) 2.44 (1.89-3.26) 2.91 (2.18-3.91) 3.41 (2.47-4.68) 3.96 (2.74-5.55) 4.75 (3.16-6.82) 5.39 (3.48-7.77) 6 -hr 1.14 (0.916-1.42) 1.35 (1.09-1.69) 1.75 (1.41-2.19) 2.13 (1.70-2.67) 2.72 (2.13-3.60) 3.23 (2.45-4.30) 3.79 (2.77-5.14) 4.40 (3.09-6.11) 5.29 (3.56-7.50) 6.01 (3.92-8.56) 12 -hr 1.33 (1.08-1.64) 1.57 (1.28-1.94) 2.01 (1.63-2.48) 2.41 (1.94-2.98) 3.01 (2.37-3.91) 3.52 (2.70-4.61) 4.07 (3.01-5.44) 4.67 (3.31-6.38) 5.52 (3.76-7.72) 6.21 (4.11-8.73) 24 -hr 1.56 (1.28-1.90) 1.82 (1.49-2.22) 2.28 (1.87-2.78) 2.69 (2.19-3.30) 3.32 (2.64-4.24) 3.84 (2.97-4.95) 4.40 (3.29-5.79) 5.00 (3.59-6.73) 5.85 (4.04-8.06) 6.54 (4.38-9.07) 2 -day 1.76 (1.47-2.12) 2.07 (1.72-2.50) 2.60 (2.16-3.14) 3.06 (2.52-3.71) 3.73 (2.98-4.67) 4.26 (3.33-5.40) 4.82 (3.64-6.24) 5.41 (3.92-7.16) 6.22 (4.33-8.43) 6.86 (4.65-9.39) 3 -day 1.92 (1.61-2.30) 2.24 (1.87-2.67) 2.77 (2.31-3.32) 3.24 (2.68-3.89) 3.91 (3.15-4.86) 4.45 (3.50-5.60) 5.02 (3.81-6.44) 5.61 (4.09-7.37) 6.43 (4.51-8.65) 7.07 (4.83-9.61) 4 -day 2.05 (1.73-2.44) 2.37 (1.99-2.82) 2.91 (2.44-3.47) 3.38 (2.82-4.05) 4.06 (3.29-5.02) 4.61 (3.64-5.76) 5.17 (3.95-6.61) 5.77 (4.23-7.54) 6.59 (4.65-8.81) 7.24 (4.97-9.78) 7 -day 2.35 (2.00-2.77) 2.72 (2.31-3.21) 3.33 (2.81-3.93) 3.84 (3.23-4.55) 4.55 (3.71-5.55) 5.11 (4.07-6.30) 5.68 (4.37-7.15) 6.26 (4.63-8.06) 7.04 (5.01-9.28) 7.64 (5.29-10.2) 10 -day 2.63 (2.25-3.08) 3.04 (2.59-3.56) 3.70 (3.15-4.35) 4.25 (3.60-5.01) 5.00 (4.09-6.04) 5.58 (4.46-6.82) 6.15 (4.75-7.67) 6.73 (5.00-8.59) 7.48 (5.35-9.78) 8.05 (5.62-10.7) 20 -day 3.49 (3.01-4.03) 3.97 (3.43-4.59) 4.74 (4.08-5.50) 5.37 (4.60-6.26) 6.22 (5.14-7.40) 6.86 (5.55-8.26) 7.49 (5.86-9.20) 8.11 (6.09-10.2) 8.91 (6.45-11.5) 9.50 (6.72-12.4) 30 -day 4.21 (3.67-4.84) 4.77 (4.14-5.48) 5.65 (4.90-6.51) 6.36 (5.48-7.35) 7.31 (6.07-8.61) 8.01 (6.52-9.56) 8.69 (6.85-10.6) 9.36 (7.08-11.7) 10.2 (7.44-13.0) 10.8 (7.71-14.0) 45 -day 5.12 (4.48-5.83) 5.80 (5.08-6.62) 6.87 (5.99-7.85) 7.71 (6.69-8.85) 8.80 (7.36-10.3) 9.60 (7.86-11.3) 10.3 (8.20-12.5) 11.1 (8.42-13.6) 11.9 (8.75-15.1) 12.5 (9.00-16.1) 60 -day 5.87 (5.17-6.66) 6.69 (5.89-7.60) 7.96 (6.98-9.05) 8.94 (7.79-10.2) 10.2 (8.52-11.8) 11.0 (9.08-13.0) 11.8 (9.43-14.2) 12.6 (9.62-15.4) 13.4 (9.91-16.9) 14.0 (10.1-17.9) 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 http://hdsc.nws.noaa.gov/hdsc/pfds/pfds firi ntpage. htm I?l at= 40.8395&l on=-104.1474&data=depth&units=engl ish&series=pds 1/4 4/7/2015 Precipitation Frequency Data Server PF graphical PDS-based depth -duration -frequency (DDF) curves Latitude: 40.8395°, Longitude: -104.1474° L r/1 to LSf? L L r44 r-1 Duration L N fly rli fl7 -0 -0 f`J fr1 r! 6 0 0 Ili d e l N rn Sr c r >, to it f13 fli 2 5 10 25 50 100 200 500 1000 NOAA Atlas 14, Volume B, Version 2 Average recurrence interval (years) Created (GMT): Tue Apr 7 15:16:26 2015 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 -min — 7 -day 60 -min — 10 -day 2 -hr — 20 -day 3 -hr — 30 -day 6 -hr - 45 -day 12 -hr — 50 -day 24 -hr http://hdsc.nws.noaa.gov/hdsc/pfds/pfds firi ntpage. htm Pl at= 40.8395&I on=-104.1474&data=depth&units=engl ish&series=pds 2/4 4/7/2015 Precipitation Frequency Data Server Back to Top Maps & aerials Small scale terrain A Medicine pow Laramie (Rational Forest -Aral aha Natiorief'l=orest- Cheyenne IJ 'Fdr_t Collins -i 7 ovelarid' r'. --4 '..1Longmont tv,, t. tTitti&t. Sc-a I a Greeley O Deriver 0 leton i a .;Centennial Fq L a .A' f't�� 1 1 t 50 km Nod S • Map dRbmoQ&fr lSeuoi Large scale terrain http://hdsc.nws.noaa.gov/hdsc/pfds/pfds firi ntpage. htm Pl at= 40.8395&l on=-104.1474&data=depth&units=engl ish&series=pds 3/4 4/7/2015 Precipitation Frequency Data Server 2 krn Map dReparciilFitafrerrgia rriflefrr 118 114 Large scale map 95 I 122 103 2 km Map c1E3aptidt iliiap3errgte Large scale aerial Back to Top US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service Office of Hydrologic Development 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.Questions@noaa.gov Disclaimer http://hdsc.nws.noaa.gov/hdsc/pfds/pfds firi ntpage. htm Pl at= 40.8395&l on=-104.1474&data=depth&units=engl ish&series=pds 414 ATTACHMENT B-3-1-2 4iT" 52 24" N M.l'k.L' ok'T 0 N. Ln Hydrologic Soil Group —Weld County, Colorado, Northern Part Jvl.E5.6 oteT Lf nS T1 S IUI 40" SL 24" N 038tZSt 3O8tSt OOTtrZSt 00b£•ZSt OOtaSP OOLZZSt CClcSt 'X'OZZSt 00£TZSt 00eizstr 6 +O090ZSt 0O93ZSt M.bl'•li ova Q 2 L L^i U1 8 L 0 Map Sole: 1:33,100 if printed on A landscape (11" x 8.5") sheet. c) _ LT1 L M .6 0hOT 4U' 44 52" N 0 - T 03 CD ct a aa) U) u) II m o up w a g go i .., 0 �N v) co z �e S O 0 a) LT Z J C ti L 9J 0 ch 2 rn L CD tl U7 O G W >- ozs re as z I- -- Z O Hydrologic Soil Group —Weld County, Colorado, Northern Part NFORMATION a. 2 MAP LEGEND The soil surveys that comprise your AOI were mapped at 1:24,000. — to c 3 a w 0 c'� 0 o a.2 L7°01' CU - U)) ,l) co a0i . t6 o i _ >` fl a o i .� _i N O. "E co Zcc .O i Q 0 as c Dc tua -+ c > CI) i'2 C it) C L A a) L t9 a O }. CO o' �Cia a) a � _ = C Tr E O_ AS E C G5 Cs 0 s_ t2 D O O O 8 a), Q) co 0 C L = to a) 0 a) o tts a to a ctE U) O 2a=o<o 0 U U Not rated or not available DEMO Area of Interest (AOl) Area of Interest (AOl) to C O t0) a 0) C to 4n Water Features Streams and Canals Transportation v! .ifs CC Interstate Highways 1 0 a) to to to 0 a 0 v U d D 0 9- v c e U a L 0. a) I— 0 4) .0 0 4, to to v CU -a O L a Major Roads Q Q a) i) 00 Ii 0 a 0 0 IZ o tcs II) 0 z r L Q -0 csi in O N 0 0 0 3- . w U Q a a r V) o c to 0 .a t Ts L v .0 it idI§ 0 0 coa0 < •C co 0 L O L <C a (13 C v E o 0 •O LOU) CO Local Roads Not rated or not available I a) 2' to 0 Aerial Photography Apr 22, 2011 —Oct 19, CS „' c o c a to C O ® c ar —Y to 0 000 Ia a> in — y .rr to U al ti 0 1E d CC5 C a C L N a a ccaa O. o c , to 0 a I.- CO � w .' co in 0 C .a 0 0 N 0 c a -0 0) ars).c o z) oas.0 =co- 75 r O ra�j0 "- CD r .r as O N 0) E as E I— U._ O a o 2:4< Q 0 m 0 0 0 ❑❑❑O b I I Nut rated or not available x 1. Soil Rating Points Conservation Service Hydrologic Soil Group —Weld County, Colorado, Northern Part Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit— Weld County, Colorado, Northern Part (CO617) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 4 Ascalon fine sandy loam, B 693.2 13.7% 0 to 6 percent slopes 11 Badland 37.2 0.7% 20 Cascajo gravelly sandy loam, 5 to 20 percent slopes A 13.8 0.3% 27 Epping silt loam, 0 to 9 percent slopes D 115.0 2.3% 29 Haverson loam, 0 to 3 percent slopes B 683.5 13.5% 31 Kim -Mitchell complex, 0 to 6 percent slopes C 1.660.5 32.7% 32 Kim -Mitchell complex, 6 to 9 percent slopes C 339.5 6.7% 40 Nunn loam, 0 to 6 percent slopes C 393 0.8% 41 Nunn clay loam. 0 to 6 percent slopes C 31.5 0.6% 46 Otero sandy loam, 0 to 3 percent slopes A 300.0 5.9% 47 Otero sandy loam, 3 to 9 percent slopes A 250.0 4.9% 51 Peetz gravelly sandy loam, 5 to 20 percent slopes A 71.9 1.4% 61 Stoneham fine sandy loam, 0 to 6 percent slopes B 296.9 5.9% 63 Tassel loamy fine sand, 5 to 20 percent slopes D 42.6 0.8% 66 Thedalund-Keota loarns, 0 to 3 percent slopes C 38.7 0.8% 70 Ustic Torriorthents-Rock outcrop complex, 9 to 40 percent slopes D 458.6 9.0% Totals for Area of Interest 5,072.2 100.0% USDA Natural Resources a Conservation Service National Cooperative Soil Survey Web Soil Survey 6/18/2015 Page 3 of 4 Hydrologic Soil Group —Weld County, Colorado, Northern Part Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, BID, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or CID), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie -break Rule: Higher USDA Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/18/2015 Page 4 of 4 ATTACHMENT B-3-1-3 N C c C c M 10 i= m M 03 a 4.1 C O e C o V rts Co 2 U W 2 0 ` r A C C L' .1 4 EE 8 1 0 ti Q. 4 5\ \ \ \ ` r \ c •\ to X11 Transform SCS Unit Hydrograph S•Graph Lag Time Subbasin Table (hr) L5 Li O a. S E 0 C q .o .o In N a V Q U 2 a 9 n Pro developmerl Sub Basin Area e `L a = O cv L c _ F o. G A .0 a v 0a cc - Fm1 naerivl r:arn.Iaie:nrnnpranciz R4 rirainsp. R*pc,rtAppy J31414rs.S+l &ha C -J a I 2 , a '(h. i'.t ----....' S noPcna \•, \ ~• A. T4 \-.\ .L; Ti l• r / /• / -LT --------- `► �i'� - 1^Re Li J•T1-L1 Transform SCS Unit Hydrograph S•Graph Lag Time Subbasin Table (hr) r I.- to M IC :V Lh it 0 M OC A N .. o C O O C O O C O O C O aaCI. aaa.aaWaaa S C .C S C i .C L a a a a 2E22E22E22F!` a c+ a a+ c, `a a. ci `c a ci a' .0 I< :0 .0 .< :0 .0 C :n .0 r< :n a 2 m a C4 > J U N U N v E V O c — a a C .q R .0 .O U) N ▪ 0 M R 'r. '0 ti 'C r N r: .+ J J J J J fl r F r •00000.0000000 n Iti I %- n I+ K n x 7 n Iti 7 C 5V 5t Ft J• — J J- J J CL H I- I- H Sub Basin Area ti e I a O. 0000000000 C)C 0C 0 0C 0 C)C 0 VJ R N- 00 ,- ti CO C Is- O a 00 q. cc:C C C .1 q ^. N'I 4' O — O O O O— C N— o 6 CC o C o o 6 o o e o 1- n M a Ir. 43 I, c. .1- N J- J J- J J a I . I i C C C ea L U rn C > ;.7. 0 ?� O ce E 0 C 2 m c C as 6 a L N a C subreaches C m a C e C IC cc CC a M M M I•: 0 0 6` N h N N h • C co e) c a case j n•C) C) C q n t� IBC I I n t) I-1 C c: C_i o o V • M1 1 J H J J a cc - Fm1 naerivl r:arn.Iaie:nrnnpranciz R4 riraina.. R*pc,rtAppy J31114rs.Sh1FI.f a J Surrrrlar/ Results for Reservers 'Pond" a A lif 4 11 H 8 88a a r. L. M1 rV N r.ry vN c o 0 'r a o M1 viICEZ figg 11..• o t' is Will 5 S R O R 0 v C C O_ W o 0 rr L Q '0 C: fTO N NC. N -- L;. C: K OIL OpC9O —N.,N Mc:, v: L717Y O C C G S:Q L{C L0Q CO'OC LDC S:QL?C 'L MJC C> W CO ^NN a: M V A Etc, C N S a C n n C n n C n n n N. • 0 O C 9 O' C O O C O O C-0 O C 9 O' -0 V 10 I: If7 L] 1: LO Li 1: by L;. I: If7 L',. 1: If7 L] 1: W 45 i. o 0 a 16 C a y O y a :4 SW . as c O O. y a W C .2 0 F 0 W G C N N- V- NC .>- CC OR'ec!G NO1x:r9:.;:c a .r no C Loa .r out! c ro o .r. no! C K' X: C> Qt C: ID-- NN r.) Vet 170.'0 c7 G C: C C. C: 0 C. C: 0 C. C: LD C. C C C. C: LO S. La LO 4. L9 14 4. La LO S. La 'a 1. La LO �. r C a V C El 45 o . W Co• 0 o. es n W CC <7 L. --i-. NN A: MOIL W N o C o o C o o C o o C o o C o o C o S: C' '={C L•)I: C L7C R. S: C 11?C G S S> W COr P. V V P. ry 'c rO rJ ' n n 1 n o n n n r. O C O O C O O C O O C O O C O O C ✓ . 1: Y] L'i 1: h] L'. 1:. h] L'. 1: h] L'. 1: Y] L'i 1: .• C) LA Ci n c C W 4. to C 0 d ix) me R R N P a a Fo R q h cn C; to in n a N V.N o el 0 '0 3 ei J:u11i 7H,S011fInin7 PA%TBN R rnrAR I n,AIiI 'I - FFru nBbri V1 ❑hI•A.Iaiunr Ap ..su tir P4 Draina•p. Rarkird.Appgmn R P-( -' KIFPab Ydalsr (aku It ant I r uryr hydmlr sy dsri ATTACHMENT B-3-1-4 HY-8 Culvert Analysis Report Crossing Discharge Data Discharge Selection Method: Specify Minimum, Design, and Maximum Flow Minimum Flow: 0 cfs Design Flow: 170 cfs Maximum Flow: 170 cfs Table 1 - Summary of Culvert Flows at Crossing: Pond crossing Headwater Elevation (ft) Total Discharge (cfs) Culvert 2 Discharge (cfs) Roadway Discharge (cfs) Iterations 5075.00 0.00 0.00 0.00 1 5076.03 17.00 17.00 0.00 1 5076.49 34.00 34.00 0.00 1 5076.86 51.00 51.00 0.00 1 5077.19 68.00 68.00 0.00 1 5077.51 85.00 85.00 0.00 1 5077.82 102.00 102.00 0.00 1 5078.13 119.00 119.00 0.00 1 5078.45 136.00 136.00 0.00 1 5078.78 153.00 153.00 0.00 1 5079.13 170.00 170.00 0.00 1 5080.50 225.65 225.65 0.00 Overtopping Rating Curve Plot for Crossing: Pond crossing Total Rating Curve Crossing: Pond crossing 5081— .g 5080— c 0 5079— a) 5078 — rd 5077 — 5076- 5075 200 0 50 100 150 Total Discharge (cfs) Table 2 - Culvert Summary Table: Culvert 2 Total Discharge (cfs) Culvert Discharge (cfs) Headwater Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwater Depth (ft) Outlet Velocity (ft/s) Tailwater Velocity (ft/s) 0.00 0.00 5075.00 0.000 0.000 0 -NF 0.000 0.000 0.000 0.000 0.000 0.000 17.00 17.00 5076.03 1.033 0.0* 1-S2n 0.656 0.709 0.656 0.352 4.561 2.413 34.00 34.00 5076.49 1.491 0.0* 1-S2n 0.930 1.018 0.930 0.538 5.518 3:163 51.00 51.00 5076.86 1.857 0.0" 1-S2n 1.143 1.256 1.143 0.690 6.210 3.698 68.00 68.00 5077.19 2.194 0.176 1-S2n 1.338 1.458 1.338 0.824 6.699 4.128 85.00 85.00 5077.51 2.512 0.540 1-S2n 1.513 1.643 1.513 0.946 7.110 4.493 102.00 102.00 5077.82 2.821 0.922 1-S2n 1.680 1.805 1.680 1.060 7.448 4.813 119.00 119.00 5078.13 3.131 1.331 1-S2n 1.841 1.955 1.841 1.167 7.736 5.100 136.00 136.00 5078.45 3.448 1.772 1-S2n 2.001 2.097 2.001 1.269 7.980 5.360 153.00 153.00 5078.78 3.779 2.241 5-S2n 2.160 2.228 2.160 1.366 8.190 5.600 170.00 170.00 5079.13 4.133 0.0* 5-S2n 2.325 2.355 2.325 1.460 8.360 5.821 * Full Flow Headwater elevation is below inlet invert. **********xxxxxxx*********xxxxx***********xxxxx**************************-kwwwxx* Straight Culvert Inlet Elevation (invert): 5075.00 ft, Outlet Elevation (invert): 5073.40 ft Culvert Length: 90.01 ft, Culvert Slope: 0.0178 lSi('i('i('i('k***iY'**** ' 'iY.lflflflf****C'RwwwifJFJFJFJFJFJFA****1S'lFiFiFiFiF:F'A"**Iii ****www .1.'***************** Culvert Performance Curve Plot: Culvert 2 Performance Curve Culvert: Culvert 2 5080- c 5079 - CD w 5078- 5- a) tj 5077 - = 5076- 507'5 • Inlet Control Elev 0 200 I• A Outlet Control Elev ea: 50 100 150 Total Discharge (cfs) • I I • Water Surface Profile Plot for Culvert: Culvert 2 Crossing - Pond crossing, Design Discharge - 170.0 cfs Culvert - Culvert 2: Culvert Discharge - 1700 cfs 5080- 5079- 5078- C o 5077- (3 a) w 5076- 5075- 5074- • — • • 80 100 120 0 20 40 60 Station (ft) Site Data - Culvert 2 Site Data Option: Culvert Invert Data Inlet Station: 10.00 ft Inlet Elevation: 5075.00 ft Outlet Station: 100.00 ft Outlet Elevation: 5073.40 ft Number of Barrels: 3 Culvert Data Summary - Culvert 2 Barrel Shape: Circular Barrel Diameter: 3.50 ft Barrel Material: Corrugated Steel Embedment: 0.00 in Barrel Manning's n: 0.0240 Culvert Type: Straight Inlet Configuration: Thin Edge Projecting Inlet Depression: NONE Roadway Data for Crossing: Pond crossing Roadway Profile Shape: Constant Roadway Elevation APPENDIX B-3-2 SURFACE WATER RUN-ON CONTROLS CALCULATION Golder Associates CALCULATIONS Date: Project No.: Site Name: Subject: February 19, 2016 1407882B Rev. 1 Pawnee Waste E&P Landfill Weld County, Colorado Made by: Checked by: Reviewed by: MBR AJ R crap g MAY j,/ )7 Al APPENDIX B-3-2: SURFACE WATER RUN-ON CONTROLS CALCULATION 1.0 OBJECTIVE Design the locations and geometry of perimeter run-on diversion channels and culverts needed to convey stormwater run-on around the Pawnee Waste E&P Landfill (Landfill). 2.0 METHODOLOGY Drainage basins (watershed areas) for the proposed surface water run-on control system were delineated based on planned and existing topography, shown in Drawing B-3-2. Times of concentration were calculated using the methodology described in TR-55 (US Soil Conservation Service 1986) for sheet flow and shallow concentrated flow, and Manning's equation for channel flow. HEC-HMS modeling software (US Army Corps of Engineers Hydrologic Engineering Center 2010) was used to determine the routing of surface runoff from the delineated drainage basins and the resulting estimated peak flows. Peak flows were used to size channels, assuming normal depths. Culverts were sized using HY-8 culvert analysis software (FHWA 2014). 3.0 ASSUMPTIONS ■ The contributing area of the upstream drainage basins total approximately 2.5 square miles. ■ A design storm event of 4.3 inches was used in this analysis. This event is the 24 -hour duration, 100 -year frequency storm event from "NOAA Atlas 14" (NOAA 2013). • The 2 -year frequency, 24 -hour duration storm depth, which is used in the TR-55 time of concentration method, is 1.8 inches (HDSC 2013). • The design storm is distributed in time as an SCS Type II synthetic distribution. • Lag time is equal to 60% of the time of concentration. • The minimum lag time is 3M minutes (a time of concentration of 5 minutes per TR-55). ■ Maximum length of sheet flow is 300 feet. i A composite SCS curve number for all basins was estimated, reflecting "Good" coverage of "Pasture, Grassland, or Range" with varying Hydrologic Soil Group (HSG) classifications. HSG values were determined from a soil map (NRCS 2014), included as Attachment B-3-2-3. • Manning's roughness coefficients of 0.035 (for design capacity) and 0.030 (for design velocity) were assumed for both grass -lined and turf -reinforcement mat (TRM)-lined channels. i:h14h1407882b10400h0403 Sop revlhappendix blapp b -311407882b app b-3-2 surface water 19feb16.clocx Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, Colorado 80228 Tel: (303) 980-0540 Fax: (303) 985-2080 www.golder_com Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation CALCULATIONS Pane 2 of 3 Project No.: 1407882B Rev. 1 Made by: MBR Site Name: Pawnee Waste E&P Landfill Checked by: AJR F P-- Az Date: February 19, 2016 Reviewed by: MAY ti A • Channels were designed using a minimum one foot of freeboard. • Culverts beneath the new access road were assumed to be concrete box culverts. 4.0 CALCULATIONS Channel reach locations and basin delineations are identified in Drawings B-3-2, B -3-3A, and B -3-3B. Hydrologic parameters for the basins (Tables B-3-2-1 and B-3-2-2) and reaches were entered into the HEC-HMS modeling software and routed to calculate peak flows for each basin and channel (Table B-3- 2-3). Channels were sized to accommodate the peak flow (Table B-3-2-4). Output from the HEC-HMS model and the HY-8 model are attached. The HEC-HMS model inputs are included as Attachment B-3-2-1; the HY-8 model is included as Attachment B-3-2-2. A riprap dissipation basin to be placed directly downstream of the culverts was also sized in HY-8 following HEC-14 methodology; the results are also included in Attachment B-3-2-2. 5.0 RESULTS/CONCLUSIONS Individual channel reach data are summarized in Table B-3-2-4, with peak flows, depths, and velocities associated with the design storm event. Perimeter channel Reaches 3 and 4 are grass -lined trapezoidal channels. Perimeter channel Reaches 0, 1, and 2 are designed to be lined with turf reinforcement matting (TRM). Four 5 -foot by 5 -foot concrete box culverts, or equivalent single -span boxculvert structure, will be constructed in the north perimeter channel to facilitate a crossing for the proposed site access road. These culverts have been sized to pass the design storm without overtopping the road. An alternate culvert crossing design andfor materials may be submitted at the time of construction as a substitute for the proposed concrete box culverts. This alternate design will provide the equivalent hydraulic performance (i.e., flow capacity) to control the design storm event and will be subject to Weld County approval. The culverts will then discharge into a riprap-lined dissipation basin to spread the flow and reduce the discharge velocity to no greater than four feet per second prior to discharge as sheet flow onto natural topography, The length of the riprap basin is designed as approximately 80 feet. A similarly sized grass -lined dissipation basin will also be placed at the terminus of Channel 4 in the southeast corner of the Facility, Stormwater flow at the terminus of Channel 4 in the southeast corner of the Facility is calculated to have a design flow velocity equal to four feet per second, and therefore will not require riprap revetment in the dissipation basin to prevent excessive erosion. i:1.14\1407882b10400\0403 ed©p revl\appendix b\app b-3\14078B2b app b-3-2 surface water 19feb16.docx Golder Associates CALCULATIONS Pace3of3 Project No.: 1407882B Rev. 1 Made by: MDR Site Name: Pawnee Waste E&P Landfill Checked by: AJR z- n S?. 12-- Date: February 19, 2016 Reviewed by: MAY riot I( 6.0 REFERENCES Hydrometeorological Design Studies Center (HDSC). 2013. Exceedance Probability Analysis for Selected Storm Events. Available online: http://www.nws.noaa.gov/oh/hdsc/aep storm analysis/ Accessed January 2, 2015. US National Oceanic and Atmospheric Administration (NOAA). 2013. Precipitation -Frequency Atlas of the United States, Atlas 14, Volume 8, Version 2M: Midwestern States Silver Spring, MD : US Department of Commerce. US Soil Conservation Service. 1986. Urban Hydrology for Small Watersheds. Washington D.C.: United States Department of Agriculture. US Army Corps of Engineers Hydrologic Engineering Center. 2010. Hydrologic Modeling System (HEC-HMS). (3.5). Davis, California: US Army Corps of Engineers. August 10. US Federal Highway Administration (FHWA). 2014. HY8 - Culverts Version 7.30 FHWA Culvert Analysis May. Washington, D.C.: FHWA Office of Technology Applications. • 1;11411407882b1040010403 edop rev1lappendix blapp h -311407882b app b-3-2 surface water 19feb16 docx Golder Associates TABLES 14078828 Rev. 1 February 2016 O it-- k\k ii‘jart 4, Date: CO2 IC Apprvd: U Project Number: Design Storm O § § it) 2c G ul 6 - - ear Depth (inches) 4.3 2 -Year Depth (inches) rli- Storm Duration (hours) 24 S = 1000 - Unit Runoff Runoff Runoff 10 Q Volume Volume CN (in) (ac -ft) (ft3) ft -- 01 2 n1-ncn mraR OOOO co gk a#r: CD %� • �Ca Mrs I 20.30 0.00 0.03 1,140 I 8.51 370.624 I R n 9 m La l' 3•j In ii % ii j CN_54 q II § O E o 00 k7 r ®,- 7 § © Z o X77%&2 7$�©. Pasture, Grassland. or Range HSG B Good Cond. (acres) kN �r- 378.42 %% c'p / Z 0GR01 0ONd 0-0@'Oo -E,m =mc 43eE•g�qG%® %700-d0~ omnm I■La k<�coce,-®-\ @ 3,_q�$ R, 04 E ®a��wed 7 E /<�. /$% enor k $ \ (10 E 7,052„311_ m w f \ a m 0 k / O—m en *� / H 1407682E Rev. TABLE B-3-2-2 BASIN TIME OF CONCENTRATION CALCULATIONS 4 i © . X tittmEN < § 2 m O a « I CO I- S Project Number: Typical Hydraulic Radius Travel (Channel Only) Time (ft) (min) OO '-B 24.2 IN R N co @ - A g e c k!2 ±EE%E o �_DDD /D_D_ c 7 c c Unpaved Unpaved E^ 2270000 w — added ©.(rN Length (it) RR,RRIR c9;382 q$,e(NR V. 5/ Shallow 22}2 k•k/k I Flow Se went 1 §e2t-«<_ /\,$$$k ypica rau is Radius (Channel Only) (ft) Roughness Condition'' Short Grass << aa. Short Grass 2 Di � 2 u 0 3— 0.087 /\ R§dd to C) re-,- C? • cF - (Sheet 300.0 CO8 '8 min 0 Sheet \// lg. is. §F99oo §R& �J�o de ma 1 -?Rego \e Rood 8179 Composite Curve Number', In 25 27 $,q ' ?— 2J{§N-NIk2 \<0-q*.mom CO noos- oelalc NO» do g 1 2 0 o — 14078828 Rev. 1 rl 2 TABLE B-3-2-2 BASIN TIME OF CONCENTRATION CALCULATIONS Zii m 4 m ce a6 ill Q CO t U Z a a co I- O Project Number: Flow Segment 4 Travel Time (min) 0) Ir co r •- UJ FTypidal Hydraulic Radius (Channel Only) (ft) -- to in; 1270 0.007 G Grass -lined I 1.25 Roughness Condition(' e V Ch O c 2 aCh1/ V' 0 0 rr (0 540 0.007 Q 0 � It) A to C t ar J "eps D O › Channel Channel To C co L I Flow Segment 3 1-13> -c rR 34.7 Typical Hydraulic Radius (Channel Only) (ft) el r ti r 0 N lc w O (Shallow 3680 0.012 U ,Unpaved Roughness Condition') Unpaved 7 to (7 Unpaved Grass -lined DOD O W .-. ti Q-.. O 0`-' O 1-10 0 H bid 0) C) .- 00 0o to b p} --+I J t7 M 8520 215 .- O T oiE O To V) id. C coCa U ,.._t ' {U GO - ;L C CC O. Composite Curve Number Li" r in N 3 0.0355 54 4 0.2530 33 C --- 'to C) u, i O C7) C C .F1 C6 3 (a) OrCV February 2016 TABLE B-3-2-3 FLOW RESULTS FROM HEC-HMS Pawnee Waste E&P Landfill Project Number: 1407882B HEC-HMS Basin Model: HEG-HMS Met. Model: HEC-HMS Control Specs: 1407882B Rev. 1 Date: _ 2119/16 By: MBR Chkd: AJR r4._ iks Apprvd: CKB c Pawnee Runon 100-yr, 24 -hr 48 -hr, 1 -min 0.01 Hydrologic Element Drainage Area (sq mile) Peak Discharge Time of (cfs) Peak 0.007 0.005 (ac -ft) Subbasin-2 1.721 513.3 01Jan2015, 13:10 1.44 Subbasin-3 0.036 11.3 01Jan2015, 12:35 1,06 Junction -3 0.036 11.3 01Jan2015, 12:35 1.06 Reach -2 0.036 11.3 01Jan2015, 12:40 1.06 Junction -2 1.756 520.3 01Jan2015, 13:09 1.43 Reach -1 1.756 520.3 01 Jan2015, 13:11 1.43 Subbasin-1 0.472 169.8 01Jan2015, 12:44 1.31 Junction -1 2.228 652.5 01Jan2015, 13:02 1.4 Reach -0 2.228 652.3 01Jan2015, 13:03 1.4 Subbasin-0 0.259 152.9 01Jan2015, 12:24 1.51 Junction -0 2.488 715.9 01Jan2015, 12:59 1.42 Sink -1 2.488 715.9 01Jan2015, 12:59 1.42 Subbasin-4 0.253 85.3 01Jan2015, 12:53 1.37 Sink -2 0.253 85.3 01Jan2015, 12:53 1.37 1:114114078828104001104D3 EDOP REVi Appendix BlApp 8-3\1407882A App 8-3-2 Pawnee Buttes Surface Water - ALB CKECK.xlsm Golder Associates t407882B Re February 2016 § a sed 2 I U tair ) ± / [ * Channel Evaluations Available Freeboard (hl ,\„ \ I I ° ir { Top Width of Channel In) ii§2§i 0 $&k ! r#■$§ instal. al Normal Depth Shear Stream Stress Power (Ib/t9) (Wfm2) 7■§t§ or§R§ Maximum Normal Flow Depth Fraud* pt) Number § ado 2N§4§ 3 owflu Maximum Velocity ((Vsec) I m \ l2gi� Wed g§§§§ � _ ...-- - - - - Mannings'n' for Capacity (Depth Calculation) § od_do §B§ Design Channel Lining UHJ /e//iii ___ I. \ Channel Design Geometry ilE »�. _ 2n , ftzee■e9 A§� F ce #2■2A# §i±mmmm3. ,lE.9,§§\ en - g§t§$ NSW °E ° - Approximate Channel Length (ft) A10O from NEC HMS NEC -HMS Element ID 'Reach Designation (chi tor III.44 , :22.412 M)2 "�� I § ! | | ATTACHMENT B-3-2-1 Attachment B-3-2-1 HEC-HMS Screen Captures and Inputs HEC-HMS Basin Model Schematic ?FJ Basin Model lPawnee Runon) i o kjl. F3i 10 — I"Ag tr%♦ ubbasln-] i 1 I\ JuncUuti D t i i Reach -I £ubbasn-1 /� % Junctlnr.-2 Reach -2 / lr f Jut -scion -3` 441-2 i,a.,�6ubDaaln 2 r./ / // / if / / i i,,3lAJDasin•3 ,f � /. J f i // ..f ,- f ! / / �o SUaD2Sln-4 ,r /! I each -u Sub Basin Area Area Subbasin (mil) Subbasin-0 0.259100 Subbasin-1 0.472000 Subbasin-2 1.720900 Subbasin-3 0.035500 Subbasin-4 0.253000 Loss SCS Curve Number Initial Abstraction Curve Impervious Subbasin (in) Number (%) Subbasin-2 69 0 Subbasin-3 63 0 Subbasin-1 67 0 Subhasin-0 70 0 Subhasin-4 68 0 Transform SCS Unit Hydrograph Graph Lag Time Subbasin Type (min) Subbasin-2 Standard 69.6 Subbasin-3 Standard 37.6 Subbasin-1 Standard 46.3 Suhbasin-0 Standard 30 Subbasin-4 Standard 54.8 Routing Muskingum-Cunge Channel Length Slope Diameter Width Side Slope Reach (ft) (ft/ft) Manning's n subreaches Shape (ft) (ft) (xH:1V) Reach -0 550.000 0.007 0.035 Trapezoid 10 3 Reach -1 935.000 0.01 0.035 Trapezoid 10 3 Reach -2 1060.000 0.01 0.035 Trapezoid 10 3 Page 1 of 1 Golder Associates, Inc. J: 114JOBSt14D1882 Pawnee Buttealn_LandtilM - Engineerng C:alculationetAppend x 13-3 Drainage Repor .Appendix 8-3-2 Runon d:versinnst14r17882A App 8-3-2 Pawnee Buttes Surface Water JULY 2D1S.xtsm 7/14/2015 ATTACHMENT B-3-2-2 HY-8 Culvert Analysis Report Water Surface Profile Plot for Culvert: Culvert 2 Crossing - Crossing 0, Design Discharge e - 715.9 cfs Culvert - Culvert 2.; Culvert Discharge - 7153 cfs 5075- 5074- 5073- 5072- -g 5071- w 5070 - 5069 - 5068 - 0 20 40 60 Station (It) 80 100 120 Table 1 - Culvert Summary Table: Culvert 2 Total Discharge (cfs) Culvert Discharge (cfs) Headwater Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flow Type Normal Depth (ft) Critical Depth (ft) Outlet Depth (ft) Tailwater Depth (ft) Outlet Velocity (ft/s) Tailwater Velocity (ft/s) 0.00 0.00 5068.00 0.000 0.000 0 -NF 0.000 0.000 0.000 0.000 0.000 0.000 71.59 71.59 5069.26 1.256 0.383 1-S2n 0.591 0.736 0.610 0.869 5.866 2.985 143.18 143.18 5069.99 1.993 0.858 1-S2n 0.957 1.168 0.973 1.302 7.360 3.805 214.77 214.77 5070.61 2.609 1.271 1-S2n 1.261 1.530 1.292 1.644 8.312 4.363 286.36 286.36 5071.14 3.143 1.662 1-S2n 1.545 1.853 1.586 1.938 9.030 4.797 357.95 357.95 5071.63 3.634 2.049 1S2n 1.818 2.151 1.863 2.198 9.606 5.154 429.54 429.54 5072.10 4.095 2.440 1-S2n 2.072 2.429 2.128 2.435 10.094 5.461 501.13 501.13 5072.54 4.540 2.879 1-S2n 2.324 2.692 2.382 2.653 10.518 5.731 572.72 572.72 5072.98 4.978 3.340 1-S2n 2.568 2.942 2.629 2.857 10.893 5.972 644.31 644.31 5073.42 5.420 3.819 5-S2n 2.808 3.182 2.869 3.048 11.229 6.192 715.90 715.90 5073.87 5.873 4.318 5-S2n 3.044 3.414 3.104 3.229 11.533 6.392 Straight Culvert Inlet Elevation (invert): 5068.00 ft, Outlet Elevation (invert): 5067.50 ft Culvert Length: 85.00 ft, Culvert Slope: 0.0059 Culvert Performance Curve Plot: Culvert 2 Performance Curve Culvert: Culvert 5075- 5074 5073 - td IT) 5072- w 5071- 7 5070 - m 5069 - 5068 Inlet Control Elev A Outlet Control Elev 200 400 500 Total Discharge (cfs) Site Data - Culvert 2 Site Data Option: Culvert Invert Data Inlet Station: 10.00 ft Inlet Elevation: 5068.00 ft Outlet Station: 95.00 ft Outlet Elevation: 5067.50 ft Number of Barrels: 4 Culvert Data Summary - Culvert 2 Barrel Shape: Concrete Box Barrel Span: 5.00 ft Barrel Rise: 5.00 ft Barrel Material: Concrete Embedment: 0.00 in Barrel Manning's n: 0.0120 Culvert Type: Straight Inlet Configuration: Square Edge (90°) Headwall Inlet Depression: NONE Crossing Discharge Data 800 Table 2 - Summary of Culvert Flows at Crossing: Crossing 0 Headwater Elevation (ft) Total Discharge (cfs) Culvert 2 Discharge (cfs) Roadway Discharge (cfs) Iterations 5068.00 0.00 0.00 0.00 1 5069.26 71.59 71.59 0.00 1 5069.99 143.18 143.18 0.00 1 5070.61 214.77 214.77 0.00 1 5071.14 286.36 286.36 0.00 1 5071.63 357.95 357.95 0.00 1 5072.10 429.54 429.54 0.00 1 5072.54 501.13 501.13 0.00 1 5072.98 572.72 572.72 0.00 1 5073.42 644.31 644.31 0.00 1 5073.87 715.90 715.90 0.00 1 5075.00 881.26 881.26 0.00 Overtopping Rating Curve Plot for Crossing: Crossing 0 Total Rating Curve Crossing: Crossing 0 5076 5075- 5074 - 2 5073 w 5072- 5071- z 5070- 5069 5068 0 200 400 600 Total Discharge (cis) 800 Table 3 - Downstream Channel Rating Curve (Crossing: Crossing 0) Flow (cfs) Water Surface Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number 0.00 5067.50 0.00 0.00 0.00 0.00 71.59 5068.37 0.87 2.98 0.27 0.59 143.18 5068.80 1.30 3.81 0.41 0.63 214/7 5069.14 1.64 4.36 0.51 0.65 286.36 5069.44 1.94 4.80 0.60 0.66 357.95 5069.70 2.20 5.15 0.69 0.67 429.54 5069.93 2.43 5.46 0.76 0.68 501.13 5070.15 2.65 5.73 0.83 0.69 572.72 5070.36 2.86 5.97 0.89 0.70 644.31 5070.55 3.05 6.19 0.95 0.70 715.90 5070.73 3.23 6.39 1.01 0.71 Tailwater Channel Data - Crossing 0 Tailwater Channel Option: Trapezoidal Channel Bottom Width: 25.00 ft Side Slope (H:V): 3.00 (_:1) Channel Slope: 0.0050 Channel Manning's n: 0.0300 Channel Invert Elevation: 5067.50 ft Roadway Data for Crossing: Crossing 0 Roadway Profile Shape: Constant Roadway Elevation Crest Length: 500.00 ft Crest Elevation: 5075.00 ft Roadway Surface: Gravel Roadway Top Width: 50.00 ft HY-8 Energy Dissipation Report External Energy Dissipator Parameter Value Units Select Culvert and Flow Crossing Crossing 0 Culvert Culvert 2 Flow 715.90 cfs Culvert Data Culvert Width (including multiple barrels) 20.0 ft Culvert Height 5.0 ft Outlet Depth 3.10 ft Outlet Velocity 11.53 ft/s Froude Number 1.15 Tailwater Depth 3.23 ft Tailwater Velocity 6.39 ft/s Tailwater Slope (SO) 0.0059 External Dissipator Data External Dissipator Category Streambed Level Structures External Dissipator Type Riprap Basin Restrictions Froude Number <3 Input Data Condition to be used to Compute Basin Outlet Velocity Best Fit Curve D50 of the Riprap Mixture Note: Minimum HS/D50 = 2 is Obtained if D50 = 0.362 ft D50 of the Riprap Mixture 0.361 ft DMax of the Riprap Mixture 1.000 ft Results Brink Depth 3.104 ft Brink Velocity 11.533 ft/s Depth (YE) 3.104 ft Riprap Thickness 1.500 ft Riprap Fareslope 2.0000 ft Check HS/D50 Note: OK if HS/D50 > 2.0 HS/D50 2.059 HS/D50 Check HS/D50 is OK Check HS/D50 Note: OK if 0.1 < D50/YE < 0.7 Check D50/YE 0.116 D50/YE Check D50/YE is OK Basin Length (LB) 80.000 ft Basin Width 73.333 ft Apron Length 20.000 ft Pool Length 60.000 ft Pool Depth (HS) 0.743 ft 1.040 TW/YE Tailwater Depth (TW) 3.229 ft Average Velocity with TW 2.779 ft/s Critical Depth (Yc) 1.417 ft Average Velocity with Yc 6.631 ft/s Downstream Riprap for High TW Distance: 1 LB Velocity 7.523 ft/s Size 0.369 ft Distance: 2 LB Velocity 3.879 ft/s Size 0.098 ft Distance: 3 LB Velocity 2.578 ft/s Size 0.043 ft Distance: 4 LB Velocity 1.930 ft/s Size 0.024 ft ATTACHMENT B-3-2-3 M ifl S obOT W to Hydrologic Soil Group —Weld County, Colorado, Northern Part M itrSi6 obOT 4 Ln a N tin Q t7 _ rLn to tin C F- S cr 00L£Z9b 1-'t Ata- .r*'ot tek re" 00£tZSt 00L£Z5t 00T£ZSt &JTEZSt O05ZZSt 00SZZSv 036TZSt 006IZ5t 00Szct 00£TZStr z O 0 00L0Z9b 00L0ZSt �r 0 t~ 0 CJ C1 0 S — M n 8 1-1 t„ S —a tin 40° 49' 56 N M „LZ S atrOT Map Scale: 1:28,600 if printed on A landscape (11" x 8.5") sheet. 58 N 4) o 0) ?:CO 7 O 0 w _ o c, O CO z a 1 3 to C 4 C g L1 tI A t 8 0 O n co OP N N C, Q .- 1 CD Lcn o = �a cal 4) w co Z M „bS .6 atrOT G5 Hydrologic Soil Group —Weld County, Colorado, Northern Part o_ 5 ce a 2 MAP LEGEND The soil surveys that comprise your AOI were mapped at 1:24;000. a C6 E O EJ1 0 0 Natural Resources Conservation Service a) '3 8 ° ♦y /U) O t cS co o co o �'co '3c� as s a) ca -o v_5 = 0 a) d can N "a 0 E "-• E . r +- :t i a) =� a) r U 100 0_O 0 13 Uc CO i s 9 "c Q• cn = to to en a Z L U) -O a) a) z "O N (D EL W NC 2 5 'Qcr7 o L 2 (a as e .. -k-2 � 0 al E stn 0) ro 03U -__cp ca a) o 2 ?-o8� Ea c aa0 -- s = to o p to O as U ...;.2 s S L a O. 0 Zs - 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L U _i of)) co a E 5 ns =E a)a....;co cv co c� > U) 0 2 2 'v 0,1"-.) o ca ci a 7+ O E a ca o .0 m O a) 0co a CO N U Q E '� E C as ZS O .a 0'- a) O— 2 fl O a) d u) L {5 3-7 u) U c N a. C a L a) =i O a. (V a) _U > Ecost 2 o 2a ¢rot 0 I— intn tr CO C o Z o ec O131111O Area of Interest (AOI) Area of Interest (AOI) Water Transportati Interstate Highways US Routes Major Roads Local Roads m cV ..i O c '- o O V O) ') as a. 0 0 d 5 as 2 •Z m m 0 U 0 Z Ca a 5 OODEMDEID O co U) .5 C O L U ITS M W Soil Rating Lines o 0 N -_ 3 a o U) r ° a) r O •— To CD E O — YO — tu a O tB E co N co.c.0 EL a) O N �= 0 s 5 U E 0 -6 .. b L To a. c ca co 0 as V a N O o s 0 cs co to a) a 2 O N N v N 4) -a . u) s a) s] a) s= L CO 000 O N :) R 2 OS L ca e O `a 3 V? O = .c C a .S} C i a to .N — o a L co co 0 N N a co v5 it �E EP 0ERE tnn o o� I- S._ o Aerial Photography o 0 < < m Not rated or not available Soil Rating Points 0 0 Q Co Co El s ■ ■ Conservation Service Hydrologic Soil Group —Weld County, Colorado, Northern Part Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit — Weld County, Colorado, Northern Part (CO617) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 4 Ascalon fine sandy loam, B 316.7 7.5% 0 to 6 percent slopes 11 Badland 28.0 0.7% 20 Cascajo gravelly sandy loam, 5 to 20 percent slopes A 26.9 0.6% 27 Epping silt loam, 0 to 9 percent slopes D 78.6 1.9% 29 Haverson loam, 0 to 3 percent slopes B 649.3 15.4% 31 Kim -Mitchell complex, 0 to 6 percent slopes C 1,531.9 36.4% 32 Kim -Mitchell complex, 6 to 9 percent slopes C 380.9 9.0% 40 Nunn loam, 0 to 6 percent slopes C 8.6 0.2% 46 Otero sandy loam, 0 to 3 percent slopes A 172.8 4.1% 47 Otero sandy loam, 3 to 9 percent slopes A 138.7 3.3% 51 Peetz gravelly sandy loam, 5 to 20 percent slopes A 71.9 1.7% 61 Stoneham fine sandy loam, 0 to 6 percent slopes B 344.8 8.2% 63 Tassel loamy fine sand, 5 to 20 percent slopes D 42.6 1.0% 66 70 Thedalund-Keota loams, 0 to 3 percent slopes Ustic Torriorthents-Rock outcrop complex, 9 to 40 percent slopes C D 38.7 381.5 0.9% 9.1% Totals for Area of Interest 4,211.8 100.0% USDA Natural Resources Web Soil Survey a Conservation Service National Cooperative Soil Survey 12/16/2014 Page 3 of 4 Hydrologic Soil Group —Weld County, Colorado, Northern Part Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and CID). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (ND, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff' None Specified Tie -break Rule: Higher USDA Natural Resources Web Soil Survey a Conservation Service National Cooperative Soil Survey 12/16/2014 Page 4of4 Hello