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Home My WebLink About20100709.tiff PRELIMINARY DRAINAGE REPORT FOR PARSONS MINE Prepared for: LAFARGE WEST, INC. 1800 North Taft Hill Road Fort Collins, Colorado 80521 D&A Job No: CG-0138.013.00 May 2008 Revised September 2009 SEP P 2 2 2009 DEERE & AULT CONSUL"I"ANTS, INC. 600 South Airport Road, Suite A-205 2010-0709 Longmont,CO 80503 (303)651-1468 • Fax (303) 651-1469 tZ OT�j0621 /y/a© 0O/ PRELIMINARY DRAINAGE REPORT FOR PARSONS MINE CERTIFICATION I hereby certify that this report (plan) for the preliminary drainage design of the Parsons Mine was prepared by me (or under my direct supervision) for the owners thereof and meets or exceeds the criteria in the Weld County Storm Drainage Criteria. %��0 t REitiff ... ,• l t.7/674.7. Al:rk A. S verin ' .7eli a Registered Professioiet} ft �<.;`• State of Colorado No. li'A Nipttitt o`°� (seal) TABLE OF CONTENTS Page INTRODUCTION 1 Purpose and Scope of Study 1 Site Conditions 1 DRAINAGE BASIN AND SUBBASINS 2 Major Basin Description 2 Subbasin Description 2 DESIGN CRITERIA 5 Design Criteria and Constraints 5 Hydrologic Criteria 5 Hydraulic Criteria 5 HYDROLOGIC RESULTS 6 Existing Conditions 6 Phase 1 Mining Conditions 7 Reclaimed Conditions 9 Comparison of Existing, Mining, and Reclaimed Conditions 13 RECLAIMED CONDITIONS 14 CONCLUSIONS 14 Compliance with Standards 14 Drainage Concept 14 REFERENCES 16 List of Figures Figure 1 Vicinity Map Figure 2 Historical Basin Subbasins List of Appendices Appendix A Reference Material Appendix B Calculations Appendix C Adjacent Property Ownership List of Exhibits Exhibit 1 Existing Drainage Conditions Exhibit 2 Phase 1 Mining Drainage Conditions Exhibit 3 Reclaimed Drainage Conditions - 1 - ee used rrermloan Drainage aevan.ao. INTRODUCTION The Parsons Mine property is located in the East 1/2 of the Southeast '/o of Section 25, Township 6 North, Range 67 West of the 6th PM; in the West % of the Southwest '/a of Section 30, Township 6 North, Range 66 West of the 6th PM; in the Northeast % of Section 36, Township 6 North, Range 67 West of the 6th PM; and in a portion of the Northwest ''/a of Section 31, Township 6 North, Range 66 West, of the 6th PM. The site is directly south of Weld County Road 64% and Weld County Road 25 bisects the property. The property contains a significant commercial deposit of sand and gravel located near the Cache La Poudre River. The majority of the site lies to the north of the Cache la Poudre River with a small portion to the south of the river in Section 36. There are several existing gravel mine operations in the project area. The Parsons Mine construction is granted by the Colorado Division of Reclamation, Mining and Safety (DRMS) permit (File Number M-2007-088). Purpose and Scope of Study This report has been prepared to document the results of a hydrologic analysis of existing, mining, and reclamation conditions of the project. Site Conditions Figure 1 is a vicinity map showing the site and surrounding area. The permit boundary will encompass approximately 381 acres, with mining activities anticipated to disturb approximately 203 acres of the site. The remaining unmined acres will be used for overburden and topsoil stockpiles, offsets from existing structures, property lines and waterways, and internal road and conveyor access. The irregularly shaped parcel is relatively flat and low lying in the greater floodplain of the Cache la Poudre River. The portion of the site to the south of the Cache la Poudre River is entirely within the jurisdictional 100-year floodplain. Approximately half of the site to the north of the Cache la Poudre River is within the 100-year floodplain. Agricultural uses surround the property with the exception of some reclaimed gravel mining ponds that are southeast of the property. The site has been drilled during sampling episodes from March of 2002 to April of 2007, and testing has been performed to verify the sand and gravel deposits are commercially marketable. Overburden exists to an average depth of approximately 7 feet over the entire site. All overburden needed for the construction of the final reclamation slopes will remain on-site. The average depth of sand and gravel is 13 feet across the site and mining at the site is intended to progress down to bedrock. The groundwater level lies approximately 5 to 15 feet below natural ground level, on average. The deposit is therefore classified as a wet alluvial deposit. However, mining operations will be carried out following dewatering. The site is owned by Lafarge West Inc.; Livingston Leigh Livestock of Weld County, LLC; and Sally A. Parsons. Lafarge has an option to purchase Sally A. Parsons' property and they have a lease to mine the Livingston Leigh Livestock of Weld County, LLC property. The mineral rights in the portions of the site that fall in Section 36 are owned by the Colorado State Board of Land - 1 - Rc,Ilea Rreli minap`nreinaee Report doev Commissioners. This affects portions of the land owned Sally A. Parsons and Livingston Leigh Livestock of Weld County, LLC. For the names of all property owners and those within 200 feet of the Parsons Mine property boundary see Appendix C. The site has historically been used as irrigated agricultural land and rangeland with approximately 98 percent pervious cover. On-site soils are 14 percent, 53 percent, 7 percent, and 26 percent Hydrologic Soil Groups A, B, C, and D, respectively according to the Soil Survey for Weld County, Colorado, Southern Part by the Soil Conservation Service(Appendix A). Portions of the site are within a Zone A floodplain according to the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) Community-Panel No. 080266- 0608-D, dated September 27, 1991 (Appendix A). The Corps of Engineers completed a Flood Insurance Study in October 2003 for the Cache la Poudre River in the vicinity of the Parsons site. This study is currently under review by FEMA but has not yet become the effective study. For the purposes of this Flood Hazard Development Permit, the 100-year floodplain and floodway boundaries of this pending study will be adopted as the best available information. The 100-year floodplain, floodway, and Base Flood Elevations (BFEs) are shown on the Firmette presented in Appendix A. DRAINAGE BASIN AND SUBBASINS Major Basin Description The Parsons Mine site is located in the lower portion of the Bracewell Basin. The Bracewell Basin is an unstudied basin that is located east of the Law Basin and west of the Coal Bank Creek Basin. Subbasin Description The existing drainage conditions at the Parsons Mine site are presented in Figure 1 and Exhibit 1. The existing historical drainage conditions were modeled as nine subbasins, H1 through H9. All the subbasins, with the exception of Subbasin H9, return storm water directly to the Cache la Poudre River once leaving the Parsons Mine site. Subbasin H9 passes storm water onto an adjacent property to the east. Portions of the site have historically been irrigated from the Whitney Ditch. All laterals on the site will be abandoned for both mining and reclamation phases of this project. Each existing drainage subbasin is described in more detail below. Subbasin H1 contains approximately 194 acres. The boundary extends from the north bank of the Cache la Poudre River in the southwest corner of the property north to the slough that runs through the property then northwestwards to the Whitney Ditch near its intersection with WCR 23 and from the intersection of the property with the Cache la Poudre River northwestwards to the Whitney Ditch near its intersection with WCR 23. The divide for drainage entering the slough provided the eastern boundary of this subbasin. The subbasin encompasses most of the Northwest One-Quarter of the Northeast One-Quarter of Section 36, and the Southeast One-Quarter of Section 25. The slope is generally between 0.5 percent and 2.0 percent with a subbasin average of 0.8 percent. - 2 - Reused Prelim[nan Drainage Report doe' Storm water drains from northwest to southeast as overland flow and returns to the Cache la Poudre River as such. The subbasin has historically been used as cropland and contains two farmsteads. Subbasin H2 contains approximately 159 acres. The boundary begins at the culvert under WCR 25 and follows the slough along its southern extent to the boundary with Subbasin Hl. The centerline of WCR 25 forms the eastern boundary and the Whitney Ditch forms the northern boundary. The subbasin is generally located in the Southeast One-Quarter of Section 25. The slope is generally between 0.5 percent and 4.0 percent with a subbasin average of 1.2 percent. Storm water drains from north to south and is collected in a slough on the southern subbasin boundary. The water is then conveyed to the Cache la Poudre River via a deep cut channel after passing through a 30 inch culvert under WCR 25. Subbasin H3 contains approximately 196 acres. The boundary extends from the south bank of the Cache la Poudre River in the southwest corner of the property south along an ancient meander of the Cache Ia Poudre River up a prominent ridge out of the floodplain, then west along the rim of the floodplain, turning back north into the floodplain to make its way back to the point where the property intersects the Cache la Poudre River. The subbasin is generally located in the East One- Half of the Southwest One-Quarter and the West One-Half of the Southeast One-Quarter of Section 36 and the Northwest One-Quarter of the Northeast On-Quarter of Section 1. The slope is generally between 0.5 percent and 25.0 percent with a subbasin average of 7.8 percent. Storm water drains from south to north and is collected in a series of gullies that open up to either overland flow within the flood plain or to the ancient meander of the river and returned to the Cache la Poudre River. Subbasin H4 contains approximately 97 acres. The Cache la Poudre River bike trail forms the northern boundary of the subbasin except for a small area along WCR 25 where the basin crosses the bike trail to return to the Cache la Poudre River. From the bike trail, the basin follows the ancient meander bounding Subbasin H3 to the rim of the floodplain then turns east to the next prominent ridge where it courses northeast to WCR 25. The subbasin is generally located in the East One-Half of the Southeast One-Quarter of Section 36 and the Northeast One-Quarter of the Northeast One-Quarter of Section 1. The slope is generally between 0.5 percent and 20.0 percent with a subbasin average of 5.0 percent. Storm water drains from south to north and is collected in a series of gullies that open up to overland flow within the flood plain and returned to the Cache Ia Poudre River near the intersection of WCR 25 and the Cache la Poudre River. Subbasin H5 contains approximately 28 acres. The ancient river meander, the Cache la Poudre River, and the Cache la Poudre River bike trail form the boundaries of this subbasin. The subbasin is generally located in the South One-Half of the Northeast One-Quarter of Section 36. The slope is generally less than 0.1 percent with a subbasin average of 0.07 percent. Storm water drains from southwest to northeast as overland flow and returned to the Cache la Poudre River as such. Subbasin H6 contains approximately 57 acres. The boundary begins at the intersection of WCR 25 and the Cache la Poudre River courses west along the north bank of the river to the intersection with the divide between Subbasins HI and H6, then north to the slough in Subbasin H2, then east to the centerline of WCR 25 which forms the eastern boundary. The subbasin is generally located in the East One-Half of the Northeast One-Quarter of Section 36. The slope is generally between 0.2 percent and 1.5 percent with a subbasin average of 0.5 percent. Storm water drains from west to - 3 - Revised PreIlminan Drainage Repoli eocx east as overland flow, is collected in the borrow ditch along WCR 25 and returned to the Cache la Poudre River. Subbasin H7 contains approximately 22 acres. The boundary extends from the intersection of WCR 25 and the Cache la Poudre River east along the north bank of the river to the west bank of the deep cut channel which drains the slough in Subbasin H2 then north along the channel to it intersection with WCR 25 and then along the centerline of WCR 25 which forms the western boundary. The subbasin is generally located in the West One-Half of the Northwest One-Quarter of Section 31. The slope is generally between 0.2 percent and 1.5 percent with a subbasin average of 0.4 percent. Storm water drains from northwest to southeast as overland flow and is returned to the Cache la Poudre River as such. Subbasin H8 contains approximately 85 acres. The boundary begins at the intersection of the eastern property line and the Cache la Poudre River and courses west along the north bank of the river to the deep cut channel draining Subbasin H2, north along the channel to the centerline of WCR 25, north along WCR to the Whitney Ditch, east along the Whitney Ditch, and then turns south to follow a divide that separates drainage that leaves the property to the neighboring lands and drainage that returns to the Cache la Poudre River directly from the property. The subbasin is generally located in the Southwest One-Quarter of Section 30 and the North One-Half of the Northwest One-Quarter of Section 31. The slope is generally between 0.5 percent and 3.3 percent with a subbasin average of 1.0 percent. Storm water drains from north to south as overland flow and is returned to the Cache la Poudre River as such. Subbasin H9 contains approximately 25 acres. The boundary follows the eastern boundary of the property and the basin divide with Subbasin H8. The subbasin is generally located in the East One- Half of the Southwest One-Quarter of Section 30. The slope is generally between 0.5 percent and 2.0 percent with a subbasin average of 1.7 percent. Storm water drains from northwest to southeast as overland flow and leaves the property as such. Drainage conditions during mining were considered for Phase 1 of the mining plan. Subsequent phases result in a similar condition for each phase. Water captured by the mining area will be pumped from the pit and discharged to the Whitney Ditch, one of the sloughs, or the Cache la Poudre River. At the close of each phase, reclamation of the completed mining phase will coincide with the mining of the subsequent phase. Phase 1 of the mining drainage conditions was modeled as 14 subbasins, P1-1 through P1-14, affecting the historical basins H2, H8, and H9, as shown on Exhibit 2. The remaining historical basins are unaffected by Phase 1 and will remain undisturbed. Each phase of the Parsons Mine site will be reclaimed immediately following the completion of the mining and will precede concurrent with mining operations in subsequent phases. The reclaimed drainage conditions were modeled as 18 subbasins, RBI through RB18, as shown on Exhibit 3. All the basins return to the historical discharge points unless captured by open water ponds left by the reclamation process. - 4 - Re ised VreOminarr Drainage Repoli dock DESIGN CRITERIA Design Criteria and Constraints This report complies with technical criteria set forth in the Weld County Storm Design Criteria and the Urban Storm Drainage Criteria Manual, Volumes 1, 2, and 3, by the Urban Drainage and Flood Control District. As previously discussed, the Parsons Mine site lies within the Bracewell Basin and previous drainage studies and/or master plans have not been developed for this basin. The constraints related to mining and reclamation of the Parsons Mine site deal primarily with mining setbacks from property boundaries, wetlands, floodway boundaries, critical wildlife habitats, and existing gas/oil wells. During mining phases, temporary topsoil and overburden stockpiles will be constructed adjacent to the mined areas. These temporary stockpiles will be located outside of the floodway boundaries and oriented parallel to the direction of overbank flow. Upon completion of the reclamation phase of the project, all temporary stockpiles will be removed and final grading within the limits of the 100-year floodplain will be to an elevation at or below pre-mining grades. Hydrologic Criteria The rational method has been used to estimate peak stormwater runoff for the 100-year storm return period for subbasins with drainage areas of 160 acres or less. Runoff from subbasins with drainage areas greater than 160 acres was estimated using the Colorado Urban Hydrograph Procedure (CUHP). Supporting calculations are provided in Appendix B. Rainfall intensity-duration- frequency data is based on information provided in the City of Greeley Storm Drainage Design Criteria and Construction Specification Document. The 100-year 1-hour storm has a magnitude of 2.78 inches. Hydraulic Criteria During the mining phases of this project, temporary minor conveyance channels will be constructed to keep runoff from frequent storm events from entering the mining areas. In many places, these minor channels will be constructed alongside temporary topsoil and overburden stockpiles. The design of these temporary conveyance channels is presented in the Erosion Control Plan. Direct precipitation on the mined areas and runoff from major storm events will be captured in the mining areas. A dewatering trench and dewatering pump will be utilized to remove this captured runoff from the mining areas. If necessary, discharge permits will be obtained for each of these dewatering discharge points to allow discharge to the natural drainageways. The runoff from the site is dramatically reduced after reclamation is completed as compared with the existing conditions. The unlined reclaimed ponds will capture and attenuate surface runoff that historically flowed across the parcels. Existing natural drainageways will remain undisturbed. For reclamation, there are no proposed hydraulic components such as conveyance channels, rundown channels, culverts, grade control structures, or detention outlets. Each of the unlined ponds will be constructed with an outlet pipe installed to maintain the normal pool elevation. - 5 - Revised Piedounar'Drainage Repon.dot\ HYDROLOGIC RESULTS Existing Conditions The CUHP2005 computer program was used to model subbasins H1 and H3. These basins exceed the 160-acre limitation of the rational method. Design storm 1-hour depths of 1.04, 1.49, 1.76, 2.51, and 2.78 inches were entered for the 2, 5, 10, 50 and 100-year storm events, respectively. Maximum depression storage depths and infiltration rates were based on SCS soil type and land use. These values are available in the City of Greeley Storm Drainage Design Criteria and Construction Specification document. Peak runoff values from all subbasins with drainage areas less than 160 acres were calculated using the rational method. All CUHP and rational method calculations are provided in Appendix B. Subbain H1 has an area of 194 acres. The imperviousness of the subbasin is 2 percent per the historical flow analysis entry in Table RO-3 of the Urban Storm Drainage Criteria Manual (USDCM) since the subbasin is predominately cropland. CUHP calculated a 100-year peak runoff of 203 cfs occurring at a time of concentration of 24.3 minutes. Subbasin HI returns to the Cache la Poudre River through overland flow. Subbasin H2 is predominately cropland with an area of 159 acres and an imperviousness of 2 percent. Based on the runoff equation in the USDCM, the runoff coefficient was calculated to be 0.400 for the 100-year storm. A time of concentration of 162 minutes would result in a 100-year rainfall intensity of 1.39 inches per hour. Applying the rational method produced a peak runoff of 87.9 cfs. Subbasin H2 collects in a slough and returns to the Cache la Poudre River via a deep cut channel. Subbasin H3 is predominately open grassland with an area of 196 acres and an imperviousness of 2 percent. CUHP calculated a 100-year peak runoff of 283 cfs occurring at a time of concentration of 18.1 minutes. Subbasin H3 collects in a series of gullies which open up into a lake or overland flow which eventually returns to the Cache la Poudre River via an ancient meander of the river which now serves as a slough. Subbasin H4 is predominately open grassland and cropland with an area of 97 acres and an imperviousness of 2 percent. The runoff coefficient was calculated to be 0.459 for the 100-year storm. A time of concentration of 62 minutes would result in a 100-year rainfall intensity of 2.75 inches per hour. Applying the rational method produced a peak runoff of 122.1 cfs. Subbasin H4 collects in a series of gullies which open up to overland flow which returns to the Cache la Poudre River as such. Subbasin H5 is entirely cropland with an area of 28 acres and an imperviousness of 0 percent. The runoff coefficient was calculated to be 0.463 for the 100-year storm. A time of concentration of 139 minutes would result in a 100-year rainfall intensity of 1.55 inches per hour. Applying the rational method produced a peak runoff of 20.2 cfs. Subbasin H5 returns to the Cache la Poudre River as overland flow. Subbasin H6 is entirely grassland with an area of 57 acres and an imperviousness of 0 percent. The runoff coefficient was calculated to be 0.329 for the 100-year storm. A time of concentration of 173 - 6 - Revised Piellminary Dninaee Report do“ minutes would result in a 100-year rainfall intensity of 1.32 inches per hour. Applying the rational method produced a peak runoff of 24.7 cfs. Subbasin H6 returns to the Cache la Poudre River as overland flow and a borrow ditch along WCR 25. Subbasin H7 is entirely grassland with an area of 22 acres and an imperviousness of 0 percent. The runoff coefficient was calculated to be 0.254 for the 100-year storm. A time of concentration of 93 minutes would result in a 100-year rainfall intensity of 2.07 inches per hour. Applying the rational method produced a peak runoff of 11.4 cfs. Subbasin H7 returns to the Cache la Poudre River as overland flow. Subbasin H8 is entirely cropland and grassland and has an area of 85 acres and an imperviousness of 0 percent. The runoff coefficient was calculated to be 0.365 for the 100-year storm. A time of concentration of 114 minutes would result in a 100-year rainfall intensity of 1.79 inches per hour. Applying the rational method produced a peak runoff of 55.4 cfs. Subbasin H8 returns to the Cache la Poudre River as overland flow. Subbasin H9 is entirely cropland and grassland with an area of 25 acres and an imperviousness of 0 percent. The runoff coefficient was calculated to be 0.416 for the 100-year storm. A time of concentration of 51 minutes would result in a 100-year rainfall intensity of 3.13 inches per hour. Applying the rational method produced a peak runoff of 32.5 cfs. Subbasin H9 passes overland flow drainage to the neighboring property to the east. Phase 1 Mining Conditions Phase 1 of the mining plan represents the initial phase of five planned phases. The processing plant and the silt storage pond created in Phase 1 will remain for all later phases of mining. The use of temporary topsoil and overburden stockpiles around the perimeter of the mining area in Phase 1 is typical of the procedure used in later phases. Mined regions are reclaimed using the temporary topsoil and overburden stockpiles at the end of each phase. Conveyors across WCR 25 and the Cache la Poudre River will be used to move mined materials to the processing plant. Lafarge anticipates mining and reclaiming the site in approximately 20 years; however, the rate of mining and overall life of the mine is dependent upon demand and market conditions. Subbasin P1-1 has an area of 11 acres. The imperviousness of the subbasin is 15 percent since the subbasin will be under mining operations. Based on the runoff equation in the USDCM, the runoff coefficient was calculated to be 0.435 for the 100-year storm. A time of concentration of 212 minutes would result in a 100-year rainfall intensity of 1.13 inches per hour. Applying the rational method produced a peak runoff of 6.2 cfs. Subbasin PI-1 collects in the borrow ditch along WCR 25 and discharges to the Cache la Poudre River via the drainage channel on the southern end of the property and contributes flow to DP8. Subbasin P1-2 has an area of 2 acres. The imperviousness of the subbasin is 15 percent since the subbasin will be under mining operations. The runoff coefficient was calculated to be 0.435 for the 100-year storm. A time of concentration of 51 minutes would result in a 100-year rainfall intensity of 3.13 inches per hour. Applying the rational method produced a peak runoff of 2.3 cfs. Subbasin P1-2 collects in a dewatering trench and is routed east to discharge off the property near where historical basin H9 had overland flow discharges and contributes flow to DP9. - 7 - Rei ised Preliminan Drainage Report doc\ Subbasin P1-3 has an area of 37 acres and is completely captured within the gravel mine and thus the peak flow was not calculated. Water collected in the mine will be pumped into a drainage swale and conveyed to the Cache la Poudre River. The storm water capture reduces flow at DP8. Subbasin P1-4 has an area of 13 acres and is completely captured within the gravel mine and thus the peak flow was not calculated. Water collected in the mine will be pumped into the Cache la Poudre River. The storm water capture reduces flow at DP8. Subbasin P1-5 has an area of 11 acres and is completely captured within the gravel mine and thus the peak flow was not calculated. Water collected in the mine will be pumped into the Cache la Poudre River. The storm water capture reduces flow at DP8. Subbasin P1-6 has an area of 4 acres. The imperviousness of the subbasin is 0 percent since the subbasin will be unaffected by the gravel operations and will remain as grassland. The runoff coefficient was calculated to be 0.365 for the 100-year storm. A time of concentration of 33 minutes would result in a 100-year rainfall intensity of 4.12 inches per hour. Applying the rational method produced a peak runoff of 5.3 cfs. Subbasin P1-6 returns to the Cache la Poudre River as overland flow and contributes flow to DP8. Subbasins P1-7 and P1-8 have a combined area of 10 acres. The imperviousness of each subbasin is 15 percent since the subbasins will be under mining operations. The runoff coefficient was calculated to be 0.452 for the 100-year storm. A time of concentration of 29 minutes would result in a 100-year rainfall intensity of 4.45 inches per hour. Applying the rational method produced a combined peak runoff of 19.2 cfs. Subbasins P1-7 and P1-8 are collected in a dewatering trench and routed off the property in the vicinity of historical overland flow discharges and contribute flow to DP9. Subbasin P1-9 has an area of 1 acre. The imperviousness of the subbasin is 10 percent since the subbasin will be used only for temporary stockpiles. The runoff coefficient was calculated to be 0.416 for the 100-year storm. A time of concentration of 9 minutes would result in a 100-year rainfall intensity of 7.83 inches per hour. Applying the rational method produced a peak runoff of 4.6 cfs. Subbasin P1-9 is routed off the property by overland flow in the vicinity of historical overland flow discharges and contributes flow to DP9. Subbasin P1-10 has an area of 6 acres and is completely captured within the gravel mine and thus the peak flow was not calculated. Water collected in the mine will be pumped into a drainage swale and conveyed to the Cache la Poudre River. The storm water capture reduces flow at DP9. Subbasin P1-11 has an area of 9 acres and is completely captured within the gravel mine and thus the peak flow was not calculated. Water collected in the mine will be pumped into the Cache la Poudre River. The storm water capture reduces flow at DP9. Subbasin P1-12 has an area of 2 acres. The imperviousness of the subbasin is 5 percent since the subbasin will be partially under mining operations and partially unaffected. The runoff coefficient was calculated to be 0.439 for the 100-year storm. A time of concentration of 27 minutes would result in a 100-year rainfall intensity of 4.64 inches per hour. Applying the rational method - 8 - Revised P'ellminx'v Drainage Repoli does produced a peak runoff of 4.3 cfs. Subbasin P1-12 is routed off the property by overland flow in the vicinity of historical overland flow discharges and contributes flow to DP9. Subbasin P1-13 has an area of 2 acres and is completely captured within the gravel mine and thus the peak flow was not calculated. Water collected in the mine will be pumped into the Cache la Poudre River. The storm water capture reduces flow at DP9. Subbasin P1-14 is predominately cropland with an area of 159 acres. The imperviousness of the subbasin is 2 percent. A portion of the basin will be used for temporary stockpiles, but these will have an insignificant affect on the imperviousness. The runoff coefficient was calculated to be 0.400 for the 100-year storm. A time of concentration of 162 minutes would result in a 100-year rainfall intensity of 1.39 inches per hour. Applying the rational method produced a peak runoff of 87.9 cfs. Subbasin P1-14 collects in a slough and returns to the Cache la Poudre River via a deep cut channel. Reclaimed Conditions This site will be mined and reclaimed to create a diverse, stable, and sustainable environment. There are significant opportunities to enhance wildlife habitat and the natural aesthetics of the Cache la Poudre River riparian corridor. The reclamation plan is designed to accommodate these opportunities. Existing riparian vegetation and wetlands have been identified and will be monitored and protected through mining and reclamation. Mining activities will be set back an appropriate distance from all areas designated for preservation. A combination of open water ponds, wetlands, and upland pastures will be created by the mining and reclamation process. Creative use of materials generated by mining and processing operations will enhance and compliment the existing riparian corridor. Silts will be used to form diverse silt basin wetlands. Excess overburden will be used to vary the shape and slopes of the finished unlined ponds. Native and adaptive plantings and ground covers will be used to restore and enhance all areas disturbed by mining activities. Subbasin RBI will be predominately grassland with an area of 134 acres. The imperviousness of the subbasin is 2 percent. Based on the runoff equation in the USDCM, the runoff coefficient was calculated to be 0.358 for the 100-year storm. A time of concentration of 153 minutes would result in a 100-year rainfall intensity of 1.45 inches per hour. Applying the rational method produced a peak runoff of 69.5 cfs. Runoff is routed through Subbasin RBI as overland flow. Subbasin RBI returns to the Cache la Poudre River as overland flow at DPI. Subbasin RB2 will be predominately grassland with an area of 45 acres. The imperviousness of the subbasin is 2 percent. The runoff coefficient was calculated to be 0.401 for the 100-year storm. A time of concentration of 95 minutes would result in a 100-year rainfall intensity of 2.04 inches per hour. Applying the rational method produced a peak runoff of 36.9 cfs. Subbasin RB2 would be captured by Pond 4C and would no longer contribute runoff to DPI. Elimination of Subbasin RB2 runoff from contributing to DPI is the major cause of the reduction from the historical peak flow rate of 203.0 cfs down to the reclaimed peak flow rate of 69.5 cfs. - 9 - Revised Preliminan Drainage Repon doe\ Subbasin RB3 will be predominately grassland with an area of 107 acres. The imperviousness of the subbasin is 2 percent. The runoff coefficient was calculated to be 0.418 for the 100-year storm. A time of concentration of 156 minutes would result in a 100-year rainfall intensity of 1.43 inches per hour. Applying the rational method produced a peak runoff of 63.5 cfs. Subbasin RB3 collects in a natural slough and returns to the Cache la Poudre River via a deep cut channel at DP2. Subbasin RB4 will be predominately grassland with an area of 38 acres. The imperviousness of the subbasin is 2 percent. The runoff coefficient was calculated to be 0.362 for the 100-year storm. A time of concentration of 105 minutes would result in a 100-year rainfall intensity of 1.90 inches per hour. Applying the rational method produced a peak runoff of 26.1 cfs. Subbasin RB4 would be captured by Pond 2A and would no longer contribute runoff to DP2. Elimination of Subbasin RB4 runoff from contributing to DP2 is the major cause of the reduction from the historical peak flow rate of 87.9 cfs down to the reclaimed peak flow rate of 63.5 cfs. Subbasin RB5 will be predominately grassland with an area of 52 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.362 for the 100-year storm. A time of concentration of 89 minutes would result in a 100-year rainfall intensity of 2.14 inches per hour. Applying the rational method produced a peak runoff of 40.5 cfs. Subbasin RB5 would be captured by Pond 1B and would no longer contribute runoff to DP8. Subbasin RB6 will be predominately grassland with an area of 28 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.369 for the 100-year storm. A time of concentration of 85 minutes would result in a 100-year rainfall intensity of 2.21 inches per hour. Applying the rational method produced a peak runoff of 22.8 cfs. Subbasin RB6 returns to the Cache la Poudre River as overland flow at DP8. Elimination of Subbasin RB5 runoff from contributing to DP8 is the major cause of the reduction from the historical peak flow rate of 55.4 cfs down to the reclaimed peak flow rate of 22.8 cfs. Subbasin RB7 will be predominately grassland with an area of 25 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.416 for the 100-year storm. A time of concentration of 51 minutes would result in a 100-year rainfall intensity of 3.13 inches per hour. Applying the rational method produced a peak runoff of 32.5 cfs. Subbasin RB7 discharges to a neighboring property as overland flow at DP9. Subbasin RB8 will be predominately grassland with an area of 3 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.407 for the 100-year storm. A time of concentration of 50 minutes would result in a 100-year rainfall intensity of 3.17 inches per hour. Applying the rational method produced a peak runoff of 3.4 cfs. Subbasin RB8 would be captured by Pond 4A and would no longer contribute runoff to DP6. Subbasin RB9 will be predominately grassland with an area of 9 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.353 for the 100-year storm. A time of concentration of 56 minutes would result in a 100-year rainfall intensity of 2.94 inches per hour. Applying the rational method produced a peak runoff of 9.7 cfs. Subbasin RB9 would be captured by Pond 4B and would no longer contribute runoff to DP6. - 10 - Rraised Yrellminary Drainage Repon.docv • Subbasin RB 18 will be predominately grassland with an area of 1 acre. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.500 for the 100-year storm. A time of concentration of 26 minutes would result in a 100-year rainfall intensity of 4.74 inches per hour. Applying the rational method produced a peak runoff of 2.6 cfs. Subbasin RBI8 would be captured by Pond 4C and would no longer contribute runoff to DP6. Subbasin RB 10 will be predominately grassland with an area of 30 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.283 for the 100-year storm. A time of concentration of 205 minutes would result in a 100-year rainfall intensity of 1.16 inches per hour. Applying the rational method produced a peak runoff of 9.7 cfs. Subbasin RB 10 returns to the Cache la Poudre River as overland flow and via the borrow ditch along WCR 25 at DP6. Elimination of Subbasin RB8, Subbasin RB9, and Subbasin RB 18 runoff from contributing to DP6 is the major cause of the reduction from the historical peak flow rate of 24.7 cfs down to the reclaimed peak flow rate of 9.7 cfs. Subbasin RBI1 will be entirely grassland with an area of 22 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.254 for the 100-year storm. A time of concentration of 93 minutes would result in a 100-year rainfall intensity of 2.07 inches per hour. Applying the rational method produced a peak runoff of 11.4 cfs. Subbasin RB11 returns to the Cache la Poudre River as overland flow at DP7. Subbasin RB12 is predominately open grassland and cropland with an area of 97 acres. The imperviousness of the subbasin is 2 percent. The runoff coefficient was calculated to be 0.459 for the 100-year storm. A time of concentration of 62 minutes would result in a 100-year rainfall intensity of 2.75 inches per hour. Applying the rational method produces a peak runoff of 122.1 cfs. Subbasin RB12 collects in a series of gullies which open up to overland flow which returns to the Cache la Poudre River as such at DP4. Subbasin RB 13 is predominately open grassland with an area of 131 acres. The imperviousness of the subbasin is 2 percent. The runoff coefficient was calculated to be 0.394 for the 100-year storm. A time of concentration of 74 minutes would result in a 100-year rainfall intensity of 2.43 inches per hour. Applying the rational method produced a peak runoff of 125.8 cfs. Subbasin RB 13 collects in a series of gullies which open up into a lake or overland flow which eventually returns to the Cache la Poudre River via an ancient meander of the river which now serves as a slough at DP3. Subbasin RB14 will be predominately grassland with an area of 63 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.364 for the 100-year storm. A time of concentration of 41 minutes would result in a 100-year rainfall intensity of 3.60 inches per hour. Applying the rational method produced a peak runoff of 82.0 cfs. Subbasin RB14 would be captured by Pond 5C and would no longer contribute runoff to DP3. Elimination of Subbasin RB14 runoff from contributing to DP3 is the major cause of the reduction from the historical peak flow rate of 283.0 cfs down to the reclaimed peak flow rate of 125.8 cfs. Subbasin RB 15 will be predominately grassland with an area of 3 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.480 for the 100-yr storm. A time of concentration of 70 minutes would result in a 100-year rainfall intensity of 2.53 inches per - 11 - Rvneee Preliminars Drainage Report does hour. Applying the rational method produced a peak runoff of 3.3 cfs. Subbasin RB 15 would be captured by Pond 5B and would no longer contribute runoff to DP5. Subbasin RB16 will be predominately grassland with an area of 4 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.480 for the 100-year storm. A time of concentration of 78 minutes would result in a 100-year rainfall intensity of 2.35 inches per hour. Applying the rational method produced a peak runoff of 4.7 cfs. Subbasin RB16 would be captured by Pond SA and would no longer contribute runoff to DP5. Subbasin RB 17 will be predominately grassland with an area of 12 acres. The imperviousness of the subbasin is 0 percent. The runoff coefficient was calculated to be 0.440 for the 100-year storm. A time of concentration of 88 minutes would result in a 100-year rainfall intensity of 2.16 inches per hour. Applying the rational method produced a peak runoff of 11.2 cfs. Subbasin RB17 returns to the Cache la Poudre River as overland flow at DP5. Elimination of Subbasin RB15 and Subbasin RB16 runoff from contributing to DP5 is the major cause of the reduction from the historical peak flow rate of 20.2 cfs down to the reclaimed peak flow rate of 11.2 cfs. Pond 1B has a surface area of 5 acres and an available storage volume for storm water capture of 16.8 acre-feet above the normal pool. The contributing drainage area to this pond includes Subbasin RB6 for a total drainage area of 57 acres. Pond 2A has a surface area of 14 acres and an available storage volume for storm water capture of 30.5 acre-feet above the normal pool. The contributing drainage area to this pond includes Subbasin RB4 for a total drainage area of 52 acres. Pond 4A has a surface area of 5 acres and an available storage volume for stone water capture of 10.8 acre-feet above the normal pool. The contributing drainage area to this pond includes Subbasin RB8 for a total drainage area of 8 acres. Pond 4B has a surface area of 9 acres and an available storage volume for storm water capture of 31.9 acre-feet above the normal pool. The contributing drainage area to this pond includes Subbasin RB9 for a total drainage area of 18 acres. Pond 4C has a surface area of 16 acres and an available storage volume for storm water capture of 36.8 acre-feet above the normal pool. The contributing drainage area to this pond includes Subbasins RB2 and RBI8 for a total drainage area of 62 acres. Pond SA has a surface area of 2 acres and an available storage volume for storm water capture of 18.2 acre-feet above the normal pool. The contributing drainage area to this pond includes Subbasin RB16 for a total drainage area of 6 acres. Pond 5B has a surface area of 7 acres and an available storage volume for storm water capture of 52.9 acre-feet above the normal pool. The contributing drainage area to this pond includes Subbasin RBI5 for a total drainage area of 9 acres. - 12 - Redsed PrcIlninery Diayneee Repon.Aoa Pond 5C has a surface area of 2 acres and an available storage volume for storm water capture of 11.4 acre-feet above the normal pool. The contributing drainage area to this pond includes Subbasin RB 14 for a total drainage area of 65 acres. Comparison of Existing, Mining, and Reclaimed Conditions Mining operations and site reclamation either will not change or will significantly reduce the drainage area and historical runoff leaving the site from each of the nine historical basins. At Design Point DP1 which includes Subbasins H1, RBI, and RB2, the peak flow rate reduces from the historical condition rate of 203.0 cfs to a reclaimed condition rate of 69.5 cfs. The drainage area contributing to flow leaving the site reduces from the historical condition of 194 acres to a reclaimed condition of 134 acres. The Phase 1 mining condition is the same as the historical condition. At Design Point DP2 which includes Subbasins H2, P1-14, RB3, and RB4, the peak flow rate reduces from the historical condition rate of 87.9 cfs to a reclaimed condition rate of 63.5 cfs. The drainage area contributing to flow leaving the site reduces from the historical condition of 159 acres to a reclaimed condition of 107 acres. The Phase 1 mining condition is the same as the historical condition. At Design Point DP3 which includes Subbasins H3, RB13, and RB14, the peak flow rate reduces from the historical condition rate of 283.0 cfs to a reclaimed condition rate of 125.8 cfs. The drainage area contributing to flow leaving the site reduces from the historical condition of 196 acres to a reclaimed condition of 131 acres. The Phase 1 mining condition is the same as the historical condition. At Design Point DP4 which includes Subbasins H4 and RB 12, the peak flow rate for both reclaimed and Phase 1 mining conditions remains unchanged from the historical condition rate of 122.1 cfs. The drainage area contributing to flow leaving the site remains unchanged from the historical condition of 97 acres. At Design Point DP5 which includes Subbasins H5, RB15, RB16, and RB17, the peak flow rate reduces from the historical condition rate of 20.2 cfs to a reclaimed condition rate of 11.2 cfs. The drainage area contributing to flow leaving the site reduces from the historical condition of 28 acres to a reclaimed condition of 12 acres. The Phase 1 mining condition is the same as the historical condition. At Design Point DP6 which includes Subbasins H6, RB9, RB9, RB10, and RB18, the peak flow rate reduces from the historical condition rate of 24.7 cfs to a reclaimed condition rate of 9.7 cfs. The drainage area contributing to flow leaving the site reduces from the historical condition of 57 acres to a reclaimed condition of 30 acres. The Phase 1 mining condition is the same as the historical condition. At Design Point DP7 which includes Subbasins 117 and RB 11, the peak flow rate for both reclaimed and Phase 1 mining conditions remains unchanged from the historical condition rate of 11.4 cfs. The drainage area contributing to flow leaving the site remains unchanged from the historical condition of 22 acres. - 13 - Revised Preliminary Drainage Repon.docx At Design Point DP8 which includes Subbasins H8, P1-1, P1-3, P1-4, P1-5, P1-6, RB5, and RB6, the peak flow rate reduces from the historical condition rate of 55.4 cfs to a reclaimed condition of 22.8 cfs and a Phase 1 mining condition rate of 11.5 cfs. The drainage area contributing to flow leaving the site reduces from the historical condition of 85 acres to a reclaimed condition of 28 acres and a Phase 1 mining condition of 15 acres. At Design Point DP9 which includes Subbasins H9, P1-2, P1-7, P1-8, P1-9, P1-10, P1-11, P1-12, P1-13, and RB7, the peak flow rate reduces from the historical condition rate of 32.5 cfs to a Phase 1 mining condition rate of 30.1 cfs. The peak flow rate for a reclaimed condition remains unchaged at 32.5 cfs. The drainage area contributing to flow leaving the site increases from the historical condition of 25 acres to a Phase 1 mining condition of 30 acres and returns to a reclaimed condition of 25 acres. RECLAIMED CONDITIONS Upon completion of the gravel mining, the site will be reclaimed as open water ponds, wetlands, and upland areas as shown in Exhibit 3. The designed spill elevation for each of the open water ponds is based on and groundwater model of the site. Each unlined pond has a minimum of approximately 2 feet of freeboard before overtopping could occur. The total effective detention volume of the reclaimed project is approximately 200 acre-feet. The surface hydrology associated with the reclaimed condition will not adversely impact the adjacent properties. Final grading will result in contours that either match or are below pre-mining contours. Surface runoff from the majority of the site will flow directly into the unlined ponds, wetlands, and upland areas. CONCLUSIONS Compliance with Standards All drainage analyses have been performed according to the Weld County Storm Drainage Criteria and the Urban Storm Drainage Criteria Manuals, Volumes I, 2, and 3 by the Urban Drainage and Flood Control District. Drainage Concept The proposed Parsons Mine development will dramatically reduce the runoff from the site due to the capture of runoff within the mining area. Although only Phase 1 of the mining plan is presented in this Preliminary Drainage Report, each of the subsequent mining phases will significantly reduce surface runoff compared to existing conditions. Upon completion of each phase of the mining project, the screening/overburden stockpile berms will be removed and used for reclamation of the unlined open water ponds, wetlands, and upland areas. - 14 - Revised hchinina,C Drninaee Repoli docx For existing conditions, the sum of all drainage basin areas is 841 acres. Direct precipitation on the reclaimed unlined ponds and the sum of the subbasin areas that would be captured by the unlined ponds is 278 acres. The reclaimed site will reduce the contributing drainage area to approximately 67 percent of the historic area without increasing the imperviousness of the contributing drainage area. - 15 - Rc ised Yrellminaq Tainape Report.doce REFERENCES Weld County Storm Drainage Criteria, Weld County Public Works Department. Soil Survey for Weld County, Colorado, Southern Part, United States Department of Agriculture, September 1980. Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District, Wright McLaughlin Engineers, Denver, Colorado, June, 2001. City of Greeley Storm Drainage Design Criteria and Construction Specification Document, City of Greeley Public Works Department - 16 - Revised Preliminary Drainage Report does APPENDIX A REFERENCE MATERIAL soil survey of Weld County, Colorado Southern Part United States Department of Agriculture Soil Conservation Service in cooperation with Colorado Agricultural Experiment Station Contents Page Page Index to soil map units iv Physical and chemical properties 63 Summary of tables v Soil and water features 64 Foreword vii Classification of the soils 65 General nature of the county 1 Soil series and morphology 66 Settlement of the county 1 Adena series 66 Natural resources 1 Altvan series 66 Farming 2 Ascalon series 66 Climate 2 Bankard series 67 How this survey was made 2 Boel series 67 General soil map for broad land use planning 3 Bresser series 67 1. Midway-Shingle 3 Cascajo series 68 2. Ulm-Nunn 3 Colby series 68 3. Weld-Colby 4 Colombo series 68 4. Wiley-Colby-Weld 4 Dacono series 68 5. Olney-Kim-Otero 4 Fort Collins series 69 6. Otero-Thedalund-Nelson 4 Haverson series 69 7. Tassel-Thedalund-Terry 4 Heldt series 69 8. Valent-Vona-Osgood 5 Julesburg series 70 9. Aquolls-Aquents-Bankard 5 Kim series 70 10. Loup-Boel 5 Loup series 70 11. Nunn-Haverson 5 Midway series 70 12. Nunn-Dacono-Altvan 6 Nelson series 71 13. Julesburg-Bresser 6 Nunn series 71 Broad land use considerations 6 Olney series 71 Soil maps for detailed planning 6 Osgood series 72 Soil descriptions 7 Otero series 72 Use and management of the soils 53 Paoli series 72 Crops and pasture 54 Renohill series 72 Yields per acre 55 Shingle series 73 Capability classes and subclasses 55 Tassel series 73 Rangeland 56 Terry series 73 Windbreaks and environmental plantings 57 Thedalund series 74 Engineering 57 Ulm series 74 Building site development 58 Valent series 74 Sanitary facilities 58 Vona series 74 Construction materials 59 Weld series 75 Water management 60 Wiley series 75 Recreation 60 References 75 Wildlife habitat 61 Glossary 75 Soil properties 62 Illustrations 81 Engineering properties 62 Tables 91 Issued September 1980 lll i I • SHEET NO. 7 II WELD COUNTY, COLORADO, SOUTHERN PART (BRACEWELLQUADRANGLE) 40° 15' 1 32,.. 24 , 19 MI ` 3 • , \N, c, -5 . ' , . J.-ISO*: , 1 33 32 $0, + 52 + 32 ... 47 ki, ' L`•'i .....--- 47 1!) 48 1 ao -I- Its. S 47 I[Ilir\--.1 -,-.....,......, ' 1-`� i'r" St � 51 •y *• ' t• 32PI Ilk\ • 47 51 F. Ilic...h *Is 25 ...--.--.- 0 Millf • 11. J 46 i 32 b 33 , 50 32.,.,...... 1044 laill4alt . i aijor -1114•1 Iiiis as. • 4 • 72i . . . _i!glfr'. • 19 19 • „ jr, ' Oil RE a:4 -N' . , 21 4 * 19 r sc • a •.C. 3 r u, r .....--.. .19 la : i%o • • z,. mow=- • S. ke !�' 2b` * •• 28 %; llafr . 0 ..pplett I - : 51 t 38'�� 51 - 61 n •53 1 b3eo 53• )061 Nit 52 47 , . .•IIIIIHI•lilikt‘ ° 52 ,0 77 rr ,�i •0 3 Pr 4e ''• ` .c 61 I 52 61 • 38 , 77 ' . a 47 r. . � 37 51 s , ;a 47 h 24 38 A ....:-.\\ f ir 52 Y 51 47 47 S 48 38 36 / r 132 SOIL SURVEY TABLE 14.--SOIL AND WATER FEATURES [Absence of an entry indicates the feature is not a concern. See text for descriptions of symbols and such terms as "rare," "brief," and "perched." The symbol < means less than; > means greater than] Flooding High water table Bedrock Soil name and Hydro- Potential map symbol logic Frequency ; Duration ;Months Depth Kind Months ;Depth Hard- frost group ness action Ft In 1 , 2 ', B None --- --- >6.0 --- --- ' >60 --- Moderate. Altvan 13;Al D Frequent_-} Aquolls ;Brief Apr-Jun 0.5-1 .0 Apparent Apr-Jun >60 --- High. Aquen is D Frequent---- Brief Apr-Jun 0.5-1 .0 Apparent Apr-Jun >60 --- High. 4* Aquolls D ,Frequent----' Brief ,Apr-Jun 0.5-1 .5 Apparent Apr-Jun >60 --- High. Aquepts D ;Frequent---- Brief ;Apr-Jun 0.5-1 .5 Apparent Apr-Jun >60 --- High. 5, 6, 7, 8, 9 B :None --- : --- >6.0 --- --- >60 --- Moderate. Ascalon q - Brief Mar-Jun >6.0 --- --- >60 --- Low. 10 ank4ard A Frequent--- 11 , 12 B ;None --- --- >6.0 --- --- >60 --- Moderate. Bresser 13 A :None --- --- >6.0 --- --- >60 --- Low. Cascajo 14, 15, 16, 17---- B ;None --- --- >6.0 --- --- >60 --- Low. Colby 18*: Colby B None --- --- >6.0 --- --- >60 --- Low. Adena C ;None --- --- >6.0 --- --- >60 --- Low. 19; 20 B ;Rare --- --- >6.0 --- --- >60 --- Moderate. ' olombo 21 , 22 C (None --- --- >6.0 --- --- >60 --- Low. Dacono 23, 24 B ;None to rare --- --- >6.0 --- --- >60 --- Low. Fort Collins 25, 26 B (Rare to Brief ;May-Sep; >6.0 --- --- >60 --- Low. Haverson common. 27, 28 C None --- --- >6.0 --- --- >60 --- Low. Heldt - , 29, 30 ; A None --- --- ; >6.0 --- --- >60 --- Moderate. Julesburg 31 , 132: 33, 34---- B None --- --- >6.0 --- >60 --- Lou. Ki4 35*: Loup D Rare to Brief ,Mar-Jun;..5-1.5 Apparent;Nov-May; >60 --- Moderate. common. Boel A ;Occasional : Brief :Mar-Jun 1 .5-3.5 Apparent;Nov-May; >60 --- Moderate. 36' Midway D ,None --- --- >6.0 --- --- 110-20 Rip- Low. pable See footnote at end of table. WELD COUNTY, COLORADO, SOUTHERN PART 133 TABLE 14.--SOIL AND WATER FEATURES--Continued Flooding High water table 1 Bedrock Soil name and Hydro- Potential map symbol logic Frequency Duration Months Depth ; Kind Months :Depth Hard- frost group ness action Ft In 36': Shingle D None --- --- >6.0 --- : --- 10-20 Rip- Low. gable 37, 38 B None --- --- >6.0 --- --- ,20-40 Rip- Low. Nelson pable 39, 40,r41% 42, ' 43 •fl C None --- --- >6.0 --- --- I >60 --- Moderate. Nunn 44, 45, 46 47, 48-___ '- B None ___ --- >6.0 --- --- >60 --- ;Low. Olney 49 A None --- --- >6.0 --- --- ', >60 --- ;Low. Osgood 15 &51 52c 53---- B None --- --- >6.0 --- --- >60 --- ':Low. ro 54, 55 B None to rare --- --- >6.0 --- --- : >60 --- ',Moderate. Paoli 56, 57 C None --- --- >6.0 --- --- ;20-40;Rip- Low. Renohill pablel 58, 59 D None --- --- >6.0 --- --- ;10-20 Rip- ',Low. Shingle pable: 60'; Shingle D None --- --- >6.0 --- --- :10-20 Rip- ;Low. pablel Renohill C None --- --- >6.0 --- --- 20-40 Rip- ',Low. pablel 61 D None --- --- >6.0 --- --- 10-20 Rip- ',Low. Tassel pablel 62, 63 B None --- --- >6.0 --- --- 20-40 Rip- [Low. Terry pablel 64, 65 C None --- --- >6.0 --- --- 20-40 Rip- :Low. Thedalund pablel 66, 67 C None --- --- >6.0 --- --- >60 --- :Low. Ulm 68" A None --- --- >6.0 ; --- --- >60 --- Low. Ustic Torriorthents 69, 70 A None --- --- >6.0 I --- I --- >60 ; --- :Low. Valent 71"• , Valent A None --- --- >6.0 --- --- >60 --- ;Low. Loup D Rare to Brief Mar-Jun +.5-1.5 Apparent:Nov-May >60 I --- ;Moderate. common. 72, 73, 74 , 75, 76, 77 B None --- --- >6.0 I --- --- >60 --- Low. Vona See footnote at end of table. .�•L- i .., F. al i 4 .. , E - 4._ ? liliqc • li,IU%7:1 Ci SC.:- -- - T il ---- 4 tillif 011‘ • 'n11.- . _ 1 l'illiallisissesslailissall- , • )1 . -:, . le. . • i -r E ! t 1i , 1 f 4. I I . 1.- 4 q I I Al i, • az )} . - -I-tell ii) _ s 7 al 5 ' K >+ lot a ,,. ,- - .14 .s • L Y .r A I • ♦ ;It 44 if I�I, ,,), p. p ta �; '' k il . ,r 4 CNI ... O i - .� a - 3 • 4: Atio _ 4 _I `l - -. .0 - 5 -fa rt •-S i u +- 9 � st r .4 . , ,.„, , It *if , it• ` V.� L#th1 . ice , P. to t 'e4, ... .. .e� '' , ,�,O`� - �Jlt • '"' N• •1 Hydrologic Soils Group: "fir t, et 1 I, u • 0 51 O ��. . 1 ,020 1 ,530 2,040 Fei 4- Hydrologic Soils Group Exhibit: DEERE & A U L T parson Mine A. 1CONSULTANTS, 1NC . Job No. 0138.013.00 Scale: 1 :8,000 r cto a a cc0 G v .. m E �+•+ LaJ �i t' co ca a Q Z CO 00 N '— a co 0 C a O to a W C W a = � w E mL � t E Or OG o- Zo N E u '0 0 C lb W _u co _ Z J � d W ai ONf. LL ; r ! t.C9 1 W N Q m o0 C .C O ,9 H = W Z ` r Z 40 aC 2 2 -0 °' � o .. �. Q W N r O ¢ a_ Z o Z c to '- ACC Q O oo w � Nm ' o Q cra Z � � co fla o ? N mNo � lE O Ce v IL. p W S .o 0 O ►-� .� 7 —� v ami N m o ``'�, O ' o � o WO z x � -�i t � EELL r W cu. V /c. - o v a et- 4 J- IU-- ------ ____ vs , - , 0- o2 E . t O_ all t - 0 I Oa 2.0 m N O u 'N 3 Y m 0 - - I m 7 N ` E in { o D C O U O Ot OLL 0o `_ C CO .o x C m " c 9 E E 3 rn --- -�` 3 o .. a . A \ \ \ 1 ( / \i 1/4 ‘ , I d \/- y 1 7 t ) 1 i c _1 o / . re- Il / / ri . ! \t ‘ii . 1 C. ..... ___..--......................4..... 1 77 / 1 ---, J I C 1 Cl)\ \/\\ _ _ _ _ __, . - - ' - - - i - >- J ? 1, i , �^' Ow w W Li-t • s\ \\ t \ \\4 I A \\-\\ • 0 � m L j ,,1112 CI Ill \\ I� �H/�� '/fir/ In 1 1`l �'c "N.1 '.., \ _ _._ \ \\\\ %....,‘ \ , ,/ o 74--- 7 - - _- - - - - -- _ - Z O (I.) r I \ ;'. � � o o11.1 1 r Q o fLL 1 \ ii w w w CO 1 (/� l \ l/eik\N„......... I I // I --// /7 I / 1 I ` N _ _ i( X / i rt. I IZy e i \/ �l I \ ,, eas).:4\ ••••• ••••............... 4.17 \ i <- _ - if= ,. (.../- _(_/_... _____ _ _ - _ _ ___ . \ _- ---.1"...) c III 2 N f, i k \ i .:: i ,•-. - \ x � \ \ I i \ 7-7Noo- \ cies\ \ Iii I ___ __ I \ ( I ` l CD - , rte, \ '. , _ __ / ~ � ``\\ y so 0\ \ Nom " 1:::\N 1 \\.....i N \\\ 1 I O I u I _.) \ p:PCI ( .....4\\ "41 iN \ 0M0 608160 olo0 suo!}ona13 pool j\s6uiMoi0 0V0\0V0\PU.Uad suosJod £10'8£l0\a6Jolol 8£l0\:d :0NIMv Ja lid 0£:£L Z 600Z •12 JaquialdaS 'XCopL. RUNOFF DRAINAGE CRITERIA MANUAL (V. 1) L = length of overland flow (500 ft maximum for non-urban land uses, 300 ft maximum for urban land uses) S= average basin slope (ft/ft) Equation RO-3 is adequate for distances up to 500 feet. Note that, in some urban watersheds, the overland flow time may be very small because flows quickly channelize. 2.4.2 Overland Travel Time For catchments with overland and channelized flow, the time of concentration needs to be considered in combination with the overland travel time, t„ which is calculated using the hydraulic properties of the swale, ditch, or channel. For preliminary work, the overland travel time, t„ can be estimated with the help of Figure RO-1 or the following equation (Guo 1999): V = C S„°5 (RO-4) in which: V=velocity (ft/sec) C.= conveyance coefficient (from Table RO-2) S„ =watercourse slope (ft/ft) Table RO-2—Conveyance Coefficient, C. Type of Land Surface Conveyance Coefficient, C, Heavy meadow 2.5 Tillage/field 5 Short pasture and lawns 7 Nearly bare ground 10 Grassed waterway 15 Paved areas and shallow paved swales 20 The time of concentration, tc, is then the sum of the initial flow time, t;, and the travel time, r„ as per Equation RO-2. 2.4.3 First Design Point Time of Concentration in Urban Catchments Using this procedure, the time of concentration at the first design point (i.e., initial flow time, r;) in an urbanized catchment should not exceed the time of concentration calculated using Equation RO-5. RO-6 6/2002 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF Table RO-3—Recommended Percentage Imperviousness Values Land Use or Percentage Surface Characteristics Imperviousness Business: Commercial areas 95 Neighborhood areas 85 Residential: Single-family Multi-unit (detached) 60 Multi-unit (attached) 75 Half-acre lot or larger Apartments 80 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 5 Playgrounds 10 Schools 50 Railroad yard areas 15 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off-site flow analysis 45 (when land use not defined) Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 0 Lawns, clayey soil 0 * See Figures RO-3 through RO-5 for percentage imperviousness. Based in part on the data collected by the District since 1969, an empirical relationship between C and the percentage imperviousness for various storm return periods was developed. Thus, values for C can be determined using the following equations (Urbonas, Guo and Tucker 1990). CA = K + (1.31i'' — 1.44/2 + 1.135i— 0.12) for CA ≥ 0, otherwise CA = 0 (RO-6) 06/2002 RO-9 I knn nrninana and Flood Control District APPENDIX B CALCULATIONS v y 3 3 3 r p O 'O D O D V O O 'O 'D U L O .V. L 9 O O 9 O O In: LI N N nee nee LL d d N N �- m v o m 0 p N LL EE 11 LL C C J 7 O 7 3 = = J J J 7 J J 3 C .J. .J. C C m a a _ a n O n n 1u 0.a a n co n o n o. O a a Cu Ciao Cu 3 10 U U N U U N U U U U U U U U U U o U UTzi., U U C L.T. J O O O m O O O C O o m re C O 4 Cn C in N r )O N O oi CN N N co r N N r 0 O CO O 'I: 4" ° Ch 0 h O LL 0 CO m co CON CO r 00 c r N M Q r N 0) O) N p1 r ' O N N N 0) Q N N M h Y O 0 Eo. Cu U O co N M ' ON. CJ ,let ^ M (O N �q„ D7 OI co r 'Cl N r N Cl N W O) r r y N N DI oo N 0 in LO on N co a O r r N r N r N r N r N r N r r N N m N N co Q Q N Q 4 N 10 N lO (O r [O N m O) O °J OJ N N m m CD 030303030D77 0 m DI A D3 D3 RK KKKM C° d' El CCK 0' C7C1 C7I D3 D3 KKKKa' KaKK � CCCID a' aa' K L 3 3 3 « 3 3 y E :: 0 0 0 0 .=0 .0 .0 .0o .202 .0 _02 .0 C Na L t LL IL LL OpddLL LL 0 L yyLLN O 0) 0) p L C J J pp 13 C a J J 73 J 0. jp O Cu O 2 co co 2 Cu ° o co co L.F. , 2 CO 0 co w co 0 o O `v CO m y o d 150000 o 3 c O O O A W J O O O CO O CD O O p O O ✓ U f; c is O 0 K 15 0 5 3 N Oz A 0q O r 0- N N D- C. Q O N Cr) N co N Ch 0') r' O 3 O O 00co IC n CO N ' N N N N r �. 6 v) N Q V N -Y03 0 LL N co co N N CD C) y m rn w a c a w J 2 • O 0 it p) ' 0) 0 0 Q r h M W r h NN t0 r el r Q co N Or r tO O) N N O d O) !r N N N N N N r N n h • ` Q N r 2 0 C Ea co r N CJ C Q r r C] V )O CO N M) O) r O O •O r c0 or )n ro r r r ` U O I I I I I I a a a a a d a m o CO d 0- EEEE a A 3 3 r o 0 0 E to p o Oo c E y LL t t LL LL 0 LL I0 L E 0 rn c m m c c 3 a o 0 E K c m 0 2 Cu Cu 2 Cu m o t fA o d d in u) d y o 0 0 m LL J O 0 O m > O 0 C 2 0 O ▪ 0: •O 3 O O p) at O co r D. N N r h Q Q or Q )O N C p ✓) ca l7 r cc)D.• co CO N N O C Q O r .. ai y N Di U LL p N N co O N N N •N- N N N N r D. 10 h to in m Y c y N a W O y ` O ' N ^ m t° r-- co Nr ANNCO NN N it a O r r r O Q N N n h N N O an N N N C r m m N co of on CO O I I I I I I I I I m c a E a E a E a E a E a ?' uo yo yo yoyo yo to to y ° of a C c .q co o a O 00 m rl 0 N E N a .0 C) o kn o N m V o L J .- m O MLei N 0. >A '.1 .l co V1 mm '4 to `' ri o m V o T i- r E 3 0 0 m m m o . N .4 TR In s u n -' a d v m N on o+ m Cr w o m N w ., a s In m o 0 y m O m 1n N tn N N .. O Ni N - CO n m 6 y V x d ix d al x of V m m N ri a 0 N N O Ni O a x 7 -i .46 O6 O w w a 4 ✓ t x s W .� 0 0 0 0 0 0 a m m m m m m m Cl m m m m o u�i X e 3 w m ni ni m m m H C co a 06 ei ; 0 0 0 0 0 0 -.m m m o+ m m " m m 0 R `• o 0 0 q — N ` d y L. a. N cis,n a c o 0 m m m m m m a. — v o e a v o d a co a q N N N N N N U E N 6 a 0 a ' O O O O U E d g d .z r, y f i= m GE � y o N a O o 0 0 O O O� 0 K .6 . 0 0 0 0 0 0 ✓ CD m O O 72 y 0 V m R fl el el .4 N el • •O 2 Z U In N 13. 0 > a w 3 - M y = i t) a N N N N N N E — .i .4 ri .-i - 3 It C C N C ^ - m m m m m m D y u E C 3 E rc , CZ• T2r) 0 x h co t N a U W G W a m a Ln Ln Ln Ln N uNi -us c a •� p o m 4 o coi `o m .a4 ti ti .a4 .a4 N O Q J L O C 2 m > 3 a n W 3 0 O V o a x m m • OI U 0 0 « 0 d • C In G 0 0 0 0 0 0 6 D G in E w CO `" = In 3 E � � 0 0 C0 t d a 4' ti W N d m N u C 0 a E 0 o Oto : = m m a+ m m m `m m ii 0 E L 0. a a N N N N N 0 re N E 0 ) ) ' ❑ 2 a U 2 e: 0 t u o 0 0 0 0 o a ry 8 - lvi c a MO- c 03 U L. =0) a E ot . -P 1 m. u� a ti .wi Ui li .`n-1 l-1 5 C ¢ _o g a g _�' v o 0 0 0 0 o E = re LL LL a a ID C Q N E m 0ci. i7) t u N U 8 m o a' B CO C c d d E E E 2 `a 0 0 In 0 >' > E '- M ci N N .-1 Vl N e_ m c C CI a a E u E A -▪ Z O 0 en 0 ✓ ri L Vi I NI �I NI NI SI 2 2 2 2 2 2 2 • Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: 1-12 Condition: Existing Storm Return Period: , Basin Chracteristics Area,A: 159 acres Basin Imperviousness' (in percent),is 2.0% Distance of Overland Flow, Lo: 3,028 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Le: 3,090 ft Hydrologic Soils Group B Percent of Basin: 74.2% Average Basin Slope,S: 0.01174 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 25.8% Slope of Channelized Flow,5„.: 0.00258 ft/ft Conveyance Coefficient2,C,: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.251 +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA?0 else CA=0 K cu =-0.39i +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB-(CA+CCD)/2 Kee =-0.18/ +0.21 For 5-yr Storm Return Period: KA =-0.081 +0.09 Kap =-0.101 +0.11 Return Period' Cwmpesae I CA I CB I Cep I KA I Kco 5-Year 0.103 0.000 0.082 0.163 0.088 0.108 10-Year 0.190 0.069 0.165 0.262 0.167 0.206 100-Year 0.400 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t;+t, l=(28.5*Pm)/(10+To)°'°'where Pity is the 1 hr point rainfall depth or to=L/180+10(if in urban area) _ Overland flow travel time equation: to= 162 min P,h, I t;=(0.395'(1.1 -CO'sgrt(La))/5033 t,= 94 min Return Period in in/hr Channelized flow travel time equation: t,= 68 min 5-Year 1.49 0.74 t, Lo/(V'60)where V=(C,'5w° ) V= 0.762 ft/s 10-Year 1.76 0.88 100-Year 2.78 1.39 Peak Flow Rate Rational Method Equation: Q=Co„,„,,,,,,,,,'I*A Return Caomposue I A Q Period in/hr acres cfs 5-Year 0.103 0.74 159 12.1 10-Year 0.190 0.88 159 26.5 100-Year 0.400 1.39 159 87S Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 tz m 0 01 w CO a a m w co n co E w m al m to m 0 a n N O n 0. - a 6' O N O .-i A O " N cn w a N o A T O S ~ E N m m w w a Ln Y L m 'RI .ai m w - N IA a d G Zr — m oO m o o a w w w w .i w 01 Li O w nn 0 w m vi n ro 0 o r '^ a 01 o N W .i n y N m w a N 'V x a x w a` In O Ln Ol In N in n at c000 w m o a " .+ .+ 0 000 x w w W y t x C m rn m m m a+ a4 at ae E m CO m m m m m m m CO w CO c m. CC n o V o 0 0 0 O O e4 A n n n n n n a - - .-. .. ., '. O � � o ^ y N N N N N N C d CO m CO a co E C W E.E. 0 0 0 0 0. jal a N a a a `-i .i .i 'y .i .i d a v a m m j q . oo ad wri m� m� c Co o E o o t7 E d E I. CO d N N n 5 F 0. 'E « L' E o o U�' a a IN b b LO LD WWD co y u u a a 66- s n n n n n n u.V OI a W N to m a 0 .g ! R in 1 C 2 I n 0 r gto a N a = I U y n n n n n n _ �. N N N N N N a C) E N N N N N N N C C 'C to E n CI E .g u E aci. ' — E o ft 0) o W m CO .C N CL m m W c N O m a m m m m m m CO a o 1."' ≤ o a v R` c wy 000000 3 CO W a w a m e. .. .y e. .l el a A t O O 0 c =co co > N S Y 3 a) t., o) 0 U o 3 Os A o L. C C t7 c N a LL Ip y m J n w w w w w w a '" o to E N MI CO co tO C d a a C V C d U w ca n 0 c C 3 N Q 0 47) yQ. Ili— m c c co 0 0 0 0 0 0 m m `m V �' CO = o a CO CO NJ %N CO NJ E D ) ) ) C' EO a A $ o E.{� o. �? o C O O O O . 'o: n 7 c t o = v o d j j of a w w w w w w a s � tnww � in vo - ., .. ., e, ., 00 LL y Y p, O y _ 9 ❑ co z n a CI ` o m p ,E ,`D_ 0. c d v to ❑ U Co W v O Co d 0 o Q E Ill t h D E a c te LE _ h E .0 o P. ❑ a a Z K h.v vo > > i t o_ °' C) O o 'n O > > Hut N el V1 N c 15 D 010101010101 '3 Lo c C• O a E w u E ▪ co 40 A Z O O vl O — —I N N H Vl N d m� m� m� cn m� ILI an 2 2 2 2 2 2 z Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: H4 Condition: Existing Storm Return Period: Basin Chracteristics Area,A: 96.9 acres Basin Imperviousness' (in percent),is 2.0% Distance of Overland Flow,L,: 2,784 ft Hydrologic Soils Group A Percent of Basin: 4.5% Distance of Channelized Flow,Lc: 1,930 ft Hydrologic Soils Group B Percent of Basin: 24.6% Average Basin Slope,S: 0.04965 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 70.9% Slope of Channelized Flow,Sw: 0.06408 ft/ft Conveyance Coefficient2,C,: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: K„ =-0.25i +0.32 CA KA+(1.31i3-1.44i2+1.1351-0.12) for CA≥0 else CA=0 Kco =-0.391 +0.46 CcD=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.141 +0.17 Cs---(CA+C00)/2 K00 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 K00 =-0.10i +0.11 Return Period] Coomposae I CA I CB I Cc0 I KA I Kco 5-Year 0.136 0.000 0.082 0.163 0.088 0.108 10-Year 0.229 0.069 0.165 0.262 0.167 0.206 100-Year 0.459 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: tc=t;+4 1=(28.5 Pm()/(10+T0)31 where Pin,is the 1hr point rainfall depth or tc=L/180+10(if in urban area) Overland flow travel time equation: t0= 62 min Pity t,=(0.395'(1.1 -C5)*sqrt(L0))/Sa33 t., 54 min Return Period in in/hr Channelized flow travel time equation: ti= 8 min 5-Year 1.49 1.47 t,L,/(V*60)where V=(C,*5/5) V= 3.797 ft/s 10-Year 1.76 1.74 100-Year 2.78 2.75 Peak Flow Rate Rational Method Equation: Q=Ccomposi,e*I A Return Ccompo:;,e I A Q Period in/hr acres cfs 5-Year 0.136 1.47 96.9 19.4 10-Year 0.229 1.74 96.9 38.7 100-Year 0.459 2.75 96.9 122.1 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: H5 Condition: Existing Storm Return Period: Basin Chracteristics Area,A: 28.2 acres Basin Imperviousness' (in percent), is 0.0% Distance of Overland Flow,Lo: 1,061 ft Hydrologic Soils Group A Percent of Basin: 12.3% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 0.0% Average Basin Slope,S: 0.00067 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 87.7% Slope of Channelized Flow,Sw: fUft Conveyance Coefficient2, Cy: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA?0 else CA=0 K00 =-0.39i +0.46 Coo=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB=(CA+C00)/2 K00 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Ka) =-0.101 +0.11 Return Period' Ceomros;te I CA I CB I CcD I KA I Kco 5-Year 0.132 0.000 0.075 0.150 0.090 0.110 10-Year 0.225 0.050 0.150 0.250 0.170 0.210 100-Year 0.463 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t;+f, 1=(28.5'P,6,)/(10+Te)B.r86 where Pin,is the 1 hr point rainfall depth or tc=L/180+10(if in urban area) _ Overland flow travel time equation: to= 139 min Pin, I 1=(0.395'(1.1 -Cs)'sgrt(L,))/So.33 t,= 139 min Return Period in in/hr Channelized flow travel time equation: t1 0 min 5-Year 1.49 0.83 t,=_,/(V'60)where V=(C,'S„:35) V= 0.000 ft/s 10-Year 1.76 0.98 100-Year 2.78 1.55 Peak Flow Rate Rational Method Equation: O=Ccomposne* I'A Return Ccompos;,e I A Q Period in/hr acres cfs 5-Year 0.132 0.83 28.2 3.1 10-Year 0.225 0.98 28.2 6.2 100-Year 0.463 1.55 28.2 20.2 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: H6 Condition: Existing Storm Return Period: Basin Chracteristics Area,A: 56.8 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,Lo: 1,764 ft Hydrologic Soils Group A Percent of Basin: 24.8% Distance of Channelized Flow,Lc: 1,055 ft Hydrologic Soils Group B Percent of Basin: 64.7% Average Basin Slope,S: 0.00496 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 105% Slope of Channelized Flow,Sy,: 0.00025 ft/ft Conveyance Coefficient2,Cv,: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA≥0 else CA=0 K co =-0.39i +0.46 Cco=Kco+(0.85813-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Car--(CA+Ca))/2 K co =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.101 +0.11 Return Period' Ccomeosue I CA I CB I CCD I KA I Kcu 5-Year 0.064 0.000 0.075 0.150 0.090 0.110 10-Year 0.136 0.050 0.150 0.250 0.170 0.210 100-Year 0.329 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t;+q l=(28.5*Pin()/(10+T0)°7 where•Pm,is the 1hr point rainfall depth or tc=L/180+10(if in urban area) Overland flow travel time equation: 4= 173 min L=(0.395*(1.1 -C5)'sgrt(L0))/S°.33 t, 99 min Return Period in in/hr Channelized flow travel time equation: t, 74 min 5-Year 1.49 0.71 t,=Le/(V*60)where V=(C, S,„0.5) V= 0.237 ft/s 10-Year 1.76 0.84 100-Year 2.78 1.32 Peak Flow Rate Rational Method Equation: o=Ccompoeue`I'A Return Ccom,,osne I A Q Period in/hr acres cfs 5-Year 0.064 0.71 56.8 2.6 10-Year 0.136 0.84 56.8 6.4 100-Year 0.329 1.32 56.8 24.7 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: H7 Condition: Existing Storm Return Period.- . Basin Chracteristics Area,A: 21.7 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,Lo: 1,300 ft Hydrologic Soils Group A Percent of Basin: 65.1% Distance of Channelized Flow,Lc: 0 ft Hydrologic Soils Group B Percent of Basin: 34.4% Average Basin Slope,S: 0.00421 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 0.6% Slope of Channelized Flow,Sw: ft/ft Conveyance Coefficient2,C,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31 i3-1.44i2+ 1.135i-0.12) for CA 2 0 else CA=0 Kco =-0.39i +0.46 Cco=Kco+(0.85813-0.786i'+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB=(CA+Cco)/2 K cD =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.10i +0.11 Return Period) Coomposue I CA I CB I CCD I KA I KBD 5-Year 0.027 0.000 0.075 0.150 0.090 0.110 10-Year 0.086 0.050 0.150 0.250 0.170 0.210 100-Year 0.254 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+t, 1=(28.5*Plh,)/(10+7O°'86 where Pin,is the l hr point rainfall depth or tc=L/180+10(if in urban area) Overland flow travel time equation: t0= 93 min P1hr t,=(0.395 (1.1 -C5)*sqrt(L0))/5033 t,= 93 min Return Period in in/hr Channelized flow travel time equation: tt= 0 min 5-Year 1.49 1.11 1,=Lo/(V*60)where V=(C,*5w") V= 0.000 ft/s 10-Year 1.76 1.31 100-Year 2.78 2.07 Peak Flow Rate Rational Method Equation: O=Coomposae•I*A Return Ccomvo:ae I A Q Period in/hr acres cfs 5-Year 0.027 1.11 21.7 0.6 10-Year 0.086 1.31 21.7 2.4 100-Year 0.254 2.07 21.7 11.4 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: H8 Condition: Existing Storm Return Period: Basin Chracteristics Area,A: 84.8 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow, Lo: 3,944 ft Hydrologic Soils Group A Percent of Basin: 2.9% Distance of Channelized Flow,L0: 0 ft Hydrologic Soils Group B Percent of Basin: 84.5% Average Basin Slope,5: 0.01028 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 12.6% Slope of Channelized Flow,Sy,: ft/ft Conveyance Coefficient,C,,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA a 0 else CA=0 Kw =-0.39i +0.46 CcD=KcO+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 C0=(C'A+COD)/2 Ken =-0.181 +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.10/ +0.11 Return Period Ccomposite CA CB COD KA • KCD 5-Year 0.082 0.000 0.075 0.150 0.090 0.110 10-Year 0.160 0.050 0.150 0.250 0.170 0.210 I 100-Year 0.365 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+t, 1=(28.5'Pin,)/(10+Te)ores where Pin,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: te= 114 min Pln, I L=(0.395"(1.1 -C5)'sgrt(L0))/S°:BB t,= 114 min Return Period in in/hr Channelized flow travel time equation: t, 0 min 5-Year 1.49 0.96 y=_,/(V'60)where V=(Cv'S„,Q5) V= 0.000 ft/s 10-Year 1.76 1.13 100-Year 2.78 1.79 Peak Flow Rate Rational Method Equation: Q=Ceompos;,e' I'A Return Ccompo5ne I A Q Period in/hr acres cfs 5-Year 0.082 0.96 84.8 6.7 10-Year 0.160 1.13 84.8 15.4 100-Year 0.365 1.79 84.8 55.4 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date. 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: H9 Condition: Existing Storm Return Period: Basin Chracteristics Area,A: 25.0 acres Basin Imperviousness' (in percent), is 0.0% Distance of Overland Flow,Lo: 1,136 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 56.3% Average Basin Slope,S: 0.01650 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 43.7% Slope of Channelized Flow,Sw: ft/ft Conveyance Coefficient',C,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA?0 else CA=0 K co =-0.39i +0.46 Ccq=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB_(CA+CcD)/2 K cD =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 K co =-0.10i +0.11 Return Period' Ccomposue I CA I CB I CCU) KA I Kco 5-Year 0.108 0.000 0.075 0.150 0.090 0.110 10-Year 0.194 0.050 0.150 0.250 0.170 0.210 100-Year 0.416 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: tc=t,+y 1=(28.5*Pit,)/(10+Tc)°'AS where Pth,is the 1 hr point rainfall depth or L=L/180+10(if in urban area) Overland flow travel time equation: tc= 51 min Pth, t,=(0.395 (1.1 -C5) sgrt(Lj))/SO33 t,= 51 min Return Period in in/hr Channelized flow travel time equation: t1 0 min 5-Year 1.49 1.68 tt=Lc/(V*60)where V=(C, 5wa5) V= 0.000 ft/s 10-Year 1.76 1.98 100-Year 2.78 3.13 Peak Flow Rate Rational Method Equation: O=Ccomposhe*I*A Return Ccomposhe I A Q Period in/hr acres cfs 5-Year 0.108 1.68 25.0 4.5 10-Year 0.194 1.98 25.0 9.6 100-Year 0.416 3.13 25.0 32.5 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum tc is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: P1-1 (H8) Condition: Developing Storm Return Period: Basin Chracteristics Area,A: 11.4 acres Basin Imperviousness' (in percent),is 15.0% Distance of Overland Flow, Lo: 0 ft Hydrologic Soils Group A Percent of Basin: 2.9% Distance of Channelized Flow,Le: 3,710 ft Hydrologic Soils Group B Percent of Basin: 84.5% Average Basin Slope,5: 0.01028 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 12.6% Slope of Channelized Flow,Sv,: 0.00085 ft/ft Conveyance Coefficient,Co: 10 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.251 +0.32 CA=KA+(1.31 i3-1.44i2+1.135i-0.12) for CA≥0 else CA=0 K00 =-0.391 +0.46 CcD=KcD+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.141 +0.17 Ca=(CA+Cm)/2 K00 =-0.181 +0.21 For 5-yr Storm Return Period: K A =-0.081 +0.09 Kco =-0.10i +0.11 Return Period' Ceomposne I CA I C8 I CcD I KA I K00 5-Year 0.175 0.100 0.168 0.236 0.078 0.095 10-Year 0.255 0.171 0.248 0.324 0.149 0.183 100-Year 0.435 0.305 0.424 0.543 0.283 0.402 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t;+t, 1=(28.5*Pin,)/(10+Te)°'86 where Pity is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: to= 212 min P1hr L=(0.395 (1.1 -C5) sgrt(Lo))/5033 t 0 min Return Period in in/hr Channelized flow travel time equation: t,= 212 min 5-Year 1.49 0.61 t1=L,/(V*60)where V=(C„*Sw°s) V= 0.292 ft/s 10-Year 1.76 0.72 100-Year 2.78 1.13 Peak Flow Rate Rational Method Equation: o=Ccomposue'I A Return C=ompo=te I A Q Period in/hr acres cfs 5-Year 0.175 0.61 11.4 1.2 10-Year 0.255 0.72 11.4 2.1 100-Year 0.435 1.13 11.4 5.6 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: P1-2(1-18) Condition: Developing Storm Return Period: Basin Chracteristics Area,A: 2.7 acres Basin Imperviousness' (in percent),is 15.0% Distance of Overland Flow,Lo: 0 ft Hydrologic Soils Group A Percent of Basin: 2.9% Distance of Channelized Flow,L0: 1,395 ft Hydrologic Soils Group B Percent of Basin: 84.5% Average Basin Slope,S: 0.01028 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 12.6% Slope of Channelized Flow,S.„: 0.00212 ft/ft Conveyance Coefficient2,C,,: 10 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA?0 else CA=0 K uD =-0.3W +0.46 Ccu=KcD+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB-(CA+CCD)/2 KcD =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 K00 =-0.10i +0.11 Return Period' Ceomposne I CA I CB I COD I KA I KcD 5-Year 0.175 0.100 0.168 0.236 0.078 0.095 10-Year 0.255 0.171 0.248 0.324 0.149 0.183 100-Year 0.435 0.305 0.424 0.543 0.283 0.402 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+t, l=(28.5*Pin,)/(10+Tj°'8fi where P,,,,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: to= 51 min Ply), I t,=(0.395'(1.1 -C5)*sqrt(L0))/S033 t,= 0 min Return Period in in/hr Channelized flow travel time equation: t1= 51 min 5-Year 1.49 1.68 t,=Lo/(V 60)where V=(C, Sw°8) V= 0.460 ft/s 10-Year 1.76 1.98 100-Year 2.78 3.13 Peak Flow Rate Rational Method Equation: Q=Ccompesne•I*A Return Ccompos,te I A Q Period in/hr acres cfs 5-Year 0.175 1.68 2.7 0.8 10-Year 0.255 1.98 2.7 1.4 100-Year 0.435 3.13 2.7 3.7 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: P1-6(HS) Condition: Developing Storm Return Period: Basin Chracteristics Area,A: 3.5 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow, Lo: 265 ft Hydrologic Soils Group A Percent of Basin: 2.9% Distance of Channelized Flow, Le: 0 ft Hydrologic Soils Group B Percent of Basin: 84.5% Average Basin Slope,S: 0.00730 ft/ft Hydrologic Soils Groups C,4 D Percent of Basin: 12.6% Slope of Channelized Flow,Sw: fUft Conveyance Coefficient2,C0: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.251 +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA?0 else CA=0 K 00 =-0.391 +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.141 +0.17 Ca=(CA+Cm)/2 Km =-0.181 +0.21 For 5-yr Storm Return Period: KA =-0.081 +0.09 Kco =-0.101 +0.11 Return Period' Ceomros,re I CA I CB I CCD I KA I Kco 5-Year 0.082 0.000 0.075 0.150 0.090 0.110 10-Year 0.160 0.050 0.150 0.250 0.170 0.210 100-Year 0.365 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t;+tt l=(28.5'Pm,)/(10+To)°re6 where Pin,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: to= 33 min Pu, I tl=(0.395'(1.1 -C5)*sgrt(Lo))/So33 t, 33 min Return Period in in/hr Channelized flow travel time equation: t, 0 min 5-Year 1.49 2.21 t, Le/(V*60)where V=(C0 Sw°s) V= 0.000 ft/s 10-Year 1.76 2.61 100-Year 2.78 4.12 Peak Flow Rate • Rational Method Equation: O=Ccomppsiie•I*A Return Crumposire I A Q Period in/hr acres _ cfs 5-Year 0.082 2.21 3.5 0.6 10-Year 0.160 2.61 3.5 1.5 100-Year 0.365 4.12 3.5 5.3 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: P1-7 (HS) &P1-8(li9) Condition: Developing Storm Return Period: Basin Chracteristics Area,A: 9.5 acres Basin Imperviousness' (in percent),is 15.0% Distance of Overland Flow,Lo: 0 ft Hydrologic Soils Group A Percent of Basin: 1.7% Distance of Channelized Flow,Lc: 1,851 ft Hydrologic Soils Group B Percent of Basin: 72.6% Average Basin Slope,S: 0.01028 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 25.7% Slope of Channelized Flow,S.„: 0.01162 ft/ft Conveyance Coefficient,Cy: 10 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA?0 else CA=0 K00 =-0.39i +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ca=(CA+Ca))/2 K00 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 K00 =-0.10i +0.11 Return Period Ccomposito 1 CA I CB I CCD I KA I Ku) 5-Year 0.185 0.100 0.168 0.236 0.078 0.095 10-Year 0.266 0.171 0.248 0.324 0.149 0.183 100-Year 0.452 0.305 0.424 0.543 0.283 0.402 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: =t,+t 1=(28.5*P )/(10+T )o roe where P is the t hrpoint rainfall depth tc , mr c Pity P or tc=L/180+10(if in urban area) Overland flow travel time equation: tc= 29 min Pin, t,=(0.395 (1.1 -C5)*sqrt(L0))/S033 f,= 0 min Return Period in in/hr Channelized flow travel time equation: t,= 29 min 5-Year 1.49 2.38 t,=Lc/(V'60)where V=(C„'S/5) V= 1.078 ft/s 10-Year 1.76 2.82 100-Year 2.78 4.45 Peak Flow Rate Rational Method Equation: Q=Ccompos,te*I *A Return Coomposite I A Q Period in/hr acres cfs 5-Year 0.185 2.38 9.5 4.2 10-Year 0.266 2.82 9.5 7.1 100-Year 0.452 4.45 9.5 19.2 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum tc is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: P1-9(H9) Condition: Developing Storm Return Period: Basin Chracteristics Area,A: 1.4 acres Basin Imperviousness'(in percent), is 0.0% Distance of Overland Flow,Lo: 36 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 56.3% Average Basin Slope,S: 0.01650 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 43.7% Slope of Channelized Flow,S„,: ft/ft Conveyance Coefficient2,C,: 10 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.251 +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA≥0 else CA=0 K DD =-0.391 +0.46 CCD=KCD+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.141 +0.17 CB-(CA+COD)/2 KCD =-0.181 +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kai =-0.10i +0.11 Return Period' Ceompos,,e I CA I CB I Cco I KA I Kco 5-Year 0.108 0.000 0.075 0.150 0.090 0.110 10-Year 0.194 0.050 0.150 0.250 0.170 0.210 100-Year 0.416 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+t, 1=(28.5'Pity)/(10+TJ)oTas where Pin,is the 1hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: t,= 9 min Pin( I t=(0.395'(1.1 -C5)*sgrt(L0))/S033 t,= 9 min Return Period in in/hr Channelized flow travel time equation: t, 0 min 5-Year 1.49 4.20 t1=1_,/(V'60)where V=(C,*5w0.5) V= 0.000 ft/s 10-Year 1.76 4.96 100-Year 2.78 7.83 Peak Flow Rate Rational Method Equation: Q=Ceompos;,e'I`A Return Coompos;,e I A Q Period in/hr acres cfs 5-Year 0.108 4.20 1.4 0.6 10-Year 0.194 4.96 1.4 1.4 100-Year 0.416 7.83 1.4 4.6 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: P1-12 (H9) Condition: Developing Storm Return Period: Basin Chracteristics Area,A: 2.1 acres Basin Imperviousness' (in percent),is 5.0% Distance of Overland Flow,Lo: 339 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 56.3% Average Basin Slope,S: 0.01650 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 43.7% Slope of Channelized Flow,S„: ft/ft Conveyance Coefficient',C,: 7 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA?0 else CA=0 Ka) =-0.39i +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ce=(CA+Cep)/2 Kco =-0.18i+0.21 For 5-yr Storm Return Period: KA =-0.08i+0.09 Kco =-0.10i+0.11 Return Period' Ceomposite I CA I Cs I CCD I KA I KcD 5-Year 0.136 0.019 0.101 0.182 0.086 0.105 10-Year 0.227 0.096 0.187 0.278 0.163 0.201 100-Year 0.439 0.241 0.379 0.517 0.308 0.441 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+t, 1=(28.5 Pin,)/(10+Te)°'°°where P,n,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: te= 27 min t;=(0.395'(1.1 -C5)*sqrt(L0))/S°.33 t,= 27 min Return Period in in/hr Channelized flow travel time equation: L= 0 min 5-Year 1.49 2.49 t, Le/(V*60)where V=(C,*S„°5) V= 0.000 f/s 10-Year 1.76 2.94 100-Year 2.78 4.64 Peak Flow Rate Rational Method Equation: Q=Ccomposne*I`A Return Ceom00,B, I A Q Period in/hr acres cfs 5-Year 0.136 2.49 2.1 0.7 10-Year 0.227 2.94 2.1 1.4 100-Year 0.439 4.64 2.1 4.3 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: P1-14(1-12) Condition: Developing Storm Return Period: Basin Chracteristics Area,A: 159 acres Basin Imperviousness' (in percent), is 2.0% Distance of Overland Flow,Lo: 3,028 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,LB: 3,090 ft Hydrologic Soils Group B Percent of Basin: 74.2% Average Basin Slope,S: 0.01174 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 25.8% Slope of Channelized Flow,S„: 0.00258 ft/ft Conveyance Coefficient,Cy: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA 2 0 else CA=0 K 00 =-0.39i +0.46 CcD=KcD+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.141+0.17 CB-(DA+CCD)/2 KcD =-0.18i+0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Ka) =-0.10i +0.11 Return Period' Ccomposae I CA I Cs I C00 I NA KcD 5-Year 0.103 0.000 0.082 0.163 0.088 0.108 10-Year 0.190 0.069 0.165 0.262 0.167 0.206 100-Year 0.400 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+ti l=(28.5*P,,,,)/(10+Te)o lee where Pin,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: tO= 162 min t,=(0.395 (1.1 -C5)*sgrt(LO))/S033 t,= 94 min Return Period in in/hr Channelized flow travel time equation: t 68 min 5-Year 1.49 0.74 t,=L0/(V*60)where V=(C, Sw°5) V= 0.762 ft/s 10-Year 1.76 0.88 100-Year 2.78 1.39 Peak Flow Rate Rational Method Equation: O=Ccomposne* I*A Return Coompos;,e I A Q Period in/hr acres cfs 5-Year 0.103 0.74 159 12.1 10-Year 0.190 0.88 159 26.5 100-Year 0.400 1.39 159 87.9 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t. is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/17/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RBI (H1) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 134 acres Basin Imperviousness' (in percent),is 2.0% Distance of Overland Flow,Lo: 5,532 ft Hydrologic Soils Group A Percent of Basin: 10.1% Distance of Channelized Flow,L0: 0 ft Hydrologic Soils Group B Percent of Basin: 82.9% Average Basin Slope,S: 0.00720 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 7.1% Slope of Channelized Flow,Sw: ft/ft Conveyance Coefficient2,C,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25/ +0.32 CA=KA+(1.310-1.44i2+ 1.135i-0.12) for CA≥0 else CA=0 K c0 =-0.39/ +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14/ +0.17 CB=(CA+Coo)/2 K co =-0.18/ +0.21 For 5-yr Storm Return Period: K A =-0.08/ +0.09 K00 =-0.10i +0.11 Return Period] Composite 1 CA I CB I CCD I KA I Ka) 5-Year 0.079 0.000 0.082 0.163 0.088 0.108 10-Year 0.163 0.069 0.165 0.262 0.167 0.206 100-Year 0.358 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t;+tr N28.5*Pis,)/(10+To)°•7 where P1,,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: t0= 153 min Pin, I t,=(0.395*(1.1 -C5)*sgrt(Lo))/S°33 t,= 153 min Return Period in in/hr Channelized flow travel time equation: t1 0 min 5-Year 1.49 0.77 t,=L0/(V*60)where V=(C,*S,„05) V= 0.000 ft/s 10-Year 1.76 0.92 100-Year 2.78 1.45 Peak Flow Rate Rational Method Equation: Q=Ccomposue*I•A Return Ccomwme I A Q Period in/hr acres cfs 5-Year 0.079 0.77 134 8.2 10-Year 0.163 0.92 134 20.0 100-Year 0.358 1.45 134 69.5 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum tc is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB2-1 (H1) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 45.0 acres Basin Imperviousness' (in percent),is 2.0% Distance of Overland Flow,Lo: 2,793 ft Hydrologic Soils Group A Percent of Basin: 1.0% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 71.5% Average Basin Slope,S: 0.00994 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 27.6% Slope of Channelized Flow,Sw: ft/ft Conveyance Coefficient2,Cv: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA at 0 else CA=0 K c0 =-0.39i +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB-(QA+Coo)/2 K c0 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.10i +0.11 Return Period' Composite 1 CA I CB I CCD I KA I Kco 5-Year 0.103 0.000 0.082 0.163 0.088 0.108 10-Year 0.191 0.069 0.165 0.262 0.167 0.206 100-Year 0.401 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+tt I=(28.5*Plhr)/(10+Te)a7es where PCB,is the 1 hr point rainfall depth or is=L/180+10(if in urban area) Overland flow travel time equation: te= 95 min Plhr I t=(0.395'(1.1 -CB)'sgrt(Lo))/S°33 t, 95 min Return Period in in/hr Channelized flow travel time equation: t1= 0 min 5-Year 1.49 1.09 ti=Le/(V'60)where V=(C,'Sw°1s) V= 0.000 ft/s 10-Year 1.76 1.29 100-Year 2.78 2.04 Peak Flow Rate Rational Method Equation: Q=Ccemmsite'I'A Return Ccempos;te I A Q Period in/hr acres cfs 5-Year 0.103 1.09 45.0 5.1 10-Year 0.191 1.29 45.0 11.1 100-Year 0.401 2.04 45.0 36.9 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB3(142) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 107 acres Basin Imperviousness' (in percent),is 2.0% Distance of Overland Flow,Lo: 3,028 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Lc: 3,090 ft Hydrologic Soils Group B Percent of Basin: 61.6% Average Basin Slope,S: 0.01467 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 38.4% Slope of Channelized Flow,Sw: 0.00241 ft/ft Conveyance Coefficient',C,: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA≥0 else CA=0 Kco =-0.391 +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14! +0.17 Ce=(CA+Cco)/2 Kco =-0.181 +0.21 For 5-yr Storm Return Period: KA =-0.081 +0.09 Ka) =-0.10i +0.11 Return Period' Ccompos,te I CA I CA I CCD I KA I Kco 5-Year 0.113 0.000 0.082 0.163 0.088 0.108 10-Year 0.202 0.069 0.165 0.262 0.167 0.206 100-Year 0.418 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: tr=t;+tt l=(28.5*P,,,,)/(10+Tc)°o783 where Pin,is the 1 hr point rainfall depth or tc=L/180+10(if in urban area) Overland flow travel time equation: tc= 156 min P,n, t;=(0.395'(1.1 -05)"sgrt(L,))/S033 t,= 86 min Return Period in in/hr Channelized flow travel time equation: t,= 70 min 5-Year 1.49 0.76 t,=-Lc/(V'60)where V=(C,*Sw05) V= 0.736 f/s 10-Year 1.76 0.90 100-Year 2.78 1.43 Peak Flow Rate Rational Method Equation: Q=Composite•I*A Return Composite I A Q Period in/hr acres cfs 5-Year 0.113 0.76 107 9.2 10-Year 0.202 0.90 107 19.5 100-Year 0.418 1.43 107 63.5 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB4-1 (1-12) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 37.9 acres Basin Imperviousness' (in percent),is 2.0% Distance of Overland Flow,Lo: 2,253 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Lo: 0 ft Hydrologic Soils Group B Percent of Basin: 100.0% Average Basin Slope,5: 0.00575 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 0.0% Slope of Channelized Flow, Sw: Rift Conveyance Coefficient2,C,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA?0 else CA=0 Kco =-0.39i +0.46 Cco=Kco+(0.85813-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ce=(CA+Ccc)/2 Kco =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.10i +0.11 Return Period' Ccomposue I CA I Ca I CCD I KA I Kco...— 5-Year 0.082 0.000 0.082 0.163 0.088 0.108 10-Year 0.165 0.069 0.165 0.262 0.167 0.206 100-Year 0.362 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity I Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: tc=t,+t, 1=(28.5`P,hr)/(10+Tc)o 756 where•P,,,,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: te-- 105 min P,6, I t=(0.395'(1.1 -C3)'sgrt(Lo))/Sa33 t= 105 min Return Period in in/hr Channelized flow travel time equation: t= 0 min 5-Year 1.49 1.02 t,Ls/(V*60)where V=(C,'Sw°5) V= 0.000 ft/s 10-Year 1.76 1.20 100-Year 2.78 1.90 Peak Flow Rate Rational Method Equation: o=Gcomposo,'I'A Return Ccomposae I A Q Period in/hr acres cfs 5-Year 0.082 1.02 37.9 3.1 10-Year 0.165 1.20 37.9 7.5 100-Year 0.362 1.90 37.9 26.1 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB5-1 (H8) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,k 52.3 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,Lo: 2,286 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 91.8% Average Basin Slope,S: 0.00965 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 8.2% Slope of Channelized Flow,Sy,: ft/ft Conveance Coefficient?,C,: 5 Y Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA z 0 else CA=0 K co =-0.39i +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ce=(CA+Cco)/2 K co =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 K cD =-0.10i +0.11 Return Period' Ccompoe;,e I CA I Ca I CCD I KA KCD 5-Year 0.081 0.000 0.075 0.150 0.090 0.110 10-Year 0.158 0.050 0.150 0.250 0.170 0.210 100-Year 0.362 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of a: to=t+ =(28.5*P,h,)1( )10+Te ores where Pier is the 1 hr point rainfall depth A 1 or to=L/180+10(if in urban area) Overland flow travel time equation: te= 89 min Pin, t,=(0.395 (1.1 -C5)*sgrt(Lo))/Sa33 q= 89 min Return Period in in/hr Channelized flow travel time equation: t, 0 min 5-Year 1.49 1.15 t,L,/(V*60)where V=(C,,'5,2 5) V= 0.000 ft/s 10-Year 1.76 1.35 100-Year 2.78 2.14 Peak Flow Rate Rational Method Equation: o=Ccomoome*I*A Return Ccompa,,e I A Q Period in/hr acres cfs 5-Year 0.081 1.15 52.3 4.9 10-Year 0.158 1.35 52.3 11.2 100-Year 0.362 2.14 52.3 40.5 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB6(1-18) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 27.9 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,Lo: 2,370 ft Hydrologic Soils Group A Percent of Basin: 8.9% Distance of Channelized Flow,Lo: 0 ft Hydrologic Soils Group B Percent of Basin: 69.5% Average Basin Slope,S: 0.01156 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 21.5% Slope of Channelized Flow,S„.: ft/ft Conveyance Coefficient,C,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA?0 else CA=0 Kcb =-0.39i +0.46 CcD=KcD+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Cs.(CA+CcD)/2 Kw =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kcb =-0.10i +0.11 Return Period' Ccomposue I CA I CB I CcD I KA I KcD 5-Year 0.084 0.000 0.075 0.150 0.090 0.110 10-Year 0.162 0.050 0.150 0.250 0.170 0.210 100-Year 0.369 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t;+t, l=(28.5*Pin,)/(10+Tc)al where Pm,is the 1 hr point rainfall depth or tort/180+10(if in urban area) Overland flow travel time equation: to= 85 min P1,, I t,=(0.395*(1.1 -C5)'sgrt(Lo))/S0-33 t,= 85 min Return Period in in/hr Channelized flow travel time equation: t, 0 min 5-Year 1.49 1.18 t,L,/(V'60)where V=(C,'5/3) V= 0.000 fts 10-Year 1.76 1.40 100-Year 2.78 2.21 Peak Flow Rate I Rational Method Equation: Q=Coomposne'I'A Return Coomposhe I A Q Period in/hr acres cfs 5-Year 0.084 1.18 27.9 2.8 10-Year 0.162 1.40 27.9 6.4 100-Year 0.369 2.21 27.9 22.8 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB7(H9) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 25.0 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,Lo: 1,136 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Lc: 0 ft Hydrologic Soils Group B Percent of Basin: 56.3% Average Basin Slope,S: 0.01650 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 43.7% Slope of Channelized Flow,S,„: ft/ft Conveyance Coefficient,C,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA a 0 else CA=0 K00 =-0.39i +0.46 CBD=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB=(CA+C00)/2 K00 =-0.18i +0.21 For 5-yr Storm Return Period: K A =-0.08i +0.09 K00 =-0.10i +0.11 Return Period! Ccompos;ie I CA I CB I C00 I KA I Kco 5-Year 0.108 0.000 0.075 0.150 0.090 0.110 10-Year 0.194 0.050 0.150 0.250 0.170 0.210 100-Year 0.416 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: 4=t1+4 I=(28.5*P,hr)/(10+TX-786 where Pin,is the 1 hr point rainfall depth or tc=L/180+10(if in urban area) Overland flow travel time equation: to= 51 min P,h, t,=(0.395"(1.1 -Cs)"sgrt(L,))/SO-33 t, 51 min Return Period in in/hr Channelized flow travel time equation: t,= 0 min 5-Year 1.49 1.68 t=Lc/(V*60)where V=(C, 5,0.5) V= 0.000 ft/s 10-Year 1.76 1.98 100-Year 2.78 3.13 Peak Flow Rate Rational Method Equation: o=Ccomposite*I"A Return Ccomposne I A Q Period in/hr acres cfs 5-Year 0.108 1.68 25.0 4.5 10-Year 0.194 1.98 25.0 9.6 100-Year 0.416 3.13 25.0 32.5 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB8-1 (H6) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 2.6 acres Basin Imperviousness'(in percent),is 0.0% Distance of Overland Flow,Lo: 492 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,L0: 0 ft Hydrologic Soils Group B Percent of Basin: 62.0% Average Basin Slope,S: 0.00496 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 38.0% Slope of Channelized Flow,S„.: ft/ft Conveyance Coefficient2,Co: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA?0 else CA=0 Kco =-0.39i +0.46 Cco=Kco+(0.858i3-0.78612+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ca=(CA+Coo)/2 Kco =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.10i +0.11 Return Period) Composite I CA I Ce I Cco I KA I Kco 5-Year 0.104 0.000 0.075 0.150 0.090 0.110 10-Year 0.188 0.050 0.150 0.250 0.170 0.210 100-Year 0.407 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+t, 1=(28.5"Pity)/(10+Te)a786 where Plh,is the t hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: to= 50 min Purr ti=(0.395*(1.1 -Co)*sgrt(Lo))/So.33 t,= 50 min Return Period in in/hr Channelized flow travel time equation: t,= 0 min 5-Year 1.49 1.70 t, Le/(V"60)where V=(C„"5,„ 5) V= 0.000 ft/s 10-Year 1.76 2.01 100-Year 2.78 3.17 Peak Flow Rate Rational Method Equation: 4=Geomposue"I"A Return Ccomposne I A Q Period in/hr acres cfs 5-Year 0.104 1.70 2.6 0.5 10-Year 0.188 2.01 2.6 1.0 100-Year 0.407 3.17 2.6 3.4 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB9-1 (H6) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 9.4 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,Lo: 585 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 98.0% Average Basin Slope, S: 0.00496 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 2.0% Slope of Channelized Flow,S„,: ft/ft Conveyance Coefficieot2,Cv: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.441+ 1.135i-0.12) for CA 20 else CA=0 Kco =-0.39i +0.46 Ccu=Kco+(0.85813-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ca=(CA+C00)/2 K 0 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 K 0 =-0.10/ +0.11 Return Period' Ccompos;,e I CA I CB I CCD I KA I Kco 5-Year 0.077 0.000 0.075 0.150 0.090 0.110 10-Year 0.152 0.050 0.150 0.250 0.170 0.210 100-Year 0.353 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: ><=t,+t, I=(28.5'Pb,,)/(10+Te)nres where Plhr is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: te= 56 min Prm I t,=(0.395"(1.1 -C5)'sgrt(L0))/50.33 t,= 56 min Return Period in in/hr Channelized flow travel time equation: t, 0 min 5-Year 1.49 1.58 t,Lo/(V'60)where V=(Cy'50.5) V= 0.000 ft's 10-Year 1.76 1.86 100-Year 2.78 2.94 Peak Flow Rate Rational Method Equation: o=Ccomposi e'I'A Return Ccompos,e I A Q Period in/hr acres cfs 5-Year 0.077 1.58 9.4 1.1 10-Year 0.152 1.86 9.4 2.7 100-Year 0.353 2.94 9.4 9.7 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB10(H6) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 29.5 acres Basin Imperviousness'(in percent),is 0.0% Distance of Overland Flow,Lo: 528 ft Hydrologic Soils Group A Percent of Basin: 48.1% Distance of Channelized Flow,Lc: 2,127 ft Hydrologic Soils Group B Percent of Basin: 48.2% Average Basin Slope,S: 0.00496 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 3.6% Slope of Channelized Flow,S„.: 0.00025 ft/ft Conveyance Coefficient2,C,: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA a 0 else CA=0 Kco =-0.39i +0.46 Cco=Kco+(0.858i3-0.786i3+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB'(CA+COD)/2 Kco =-0.181 +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Ku) =-0.10i +0.11 Return Period' Ccomposite I CA I CB I CCD I KA I Kco 5-Year 0.042 0.000 0.075 0.150 0.090 0.110 10-Year 0.105 0.050 0.150 0.250 0.170 0.210 100-Year 0.283 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: tc=t,+t, 1=(28.5 Pin,)/(10+Tc)°786 where Pin,is the 1 hr point rainfall depth or tc=L/180+10(if in urban area) Overland flow travel time equation: tc= 205 min Prm t=(0.395'(1.1 -C5) sqrt(L0))/5a33 t;= 55 min Return Period in in/hr Channelized flow travel time equation: t, 150 min 5-Year 1.49 0.62 t,=Lc/(V*60)where V=(C, Swa3) V= 0.237 f/s 10-Year 1.76 0.74 100-Year 2.78 1.16 Peak Flow Rate Rational Method Equation: O=Gcomposi,e*I*A Return Ccomposue I A Q Period in/hr acres cfs 5-Year 0.042 0.62 29.5 0.8 10-Year 0.105 0.74 29.5 2.3 100-Year 0.283 1.16 29.5 9.7 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum tc is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB11 (H7) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 21.7 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,L,: 1,300 ft Hydrologic Soils Group A Percent of Basin: 65.1% Distance of Channelized Flow,Lo: 0 ft Hydrologic Soils Group B Percent of Basin: 34.4% Average Basin Slope,S: 0.00421 ft/ft Hydrologic Soils Groups C 8 D Percent of Basin: 0.6% Slope of Channelized Flow,Sw: ft/ft Conveyance Coefficient2,C,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA s 0 else CA=0 K00 =-0.39i +0.46 Cco=KcD+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ce=(CA+Cco)/2 K eD =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.10i +0.11 Return Period) Ccomcosne I CA I CB I C09 I KA I KcD 5-Year 0.027 0.000 0.075 0.150 0.090 0.110 10-Year 0.086 0.050 0.150 0.250 0.170 0.210 100-Year 0.254 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser ofe: to=t,+y 1=(28.5 Pity)/(10+T )ogee where Pin,is the 1 hr point rainfall depth or te=L/180+10(if in urban area) Overland flow travel time equation: t0 93 min Plhr t,=(0.395'(1.1 -C5) sgrt(L,))/S033 t,,= 93 min Return Period in in/hr Channelized flow travel time equation: t,= 0 min 5-Year 1.49 1.11 tt=Le/(V*60)where V=(C,*Sw65) V= 0.000 ft/s 10-Year 1.76 1.31 100-Year 2.78 2.07 Peak Flow Rate Rational Method Equation: O=Ceomoosne*I*A Return Ccomposne I A Q Period in/hr acres cfs 5-Year 0.027 1.11 21.7 0.6 10-Year 0.086 1.31 21.7 2.4 100-Year 0.254 2.07 21.7 11.4 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t. is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB12(H4) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 96.9 acres Basin Imperviousness' (in percent),is 2.0% Distance of Overland Flow,Lo: 2,784 ft Hydrologic Soils Group A Percent of Basin: 4.5% Distance of Channelized Flow, Lo: 1,930 ft Hydrologic Soils Group B Percent of Basin: 24.6% Average Basin Slope,S: 0.04965 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 70.9% Slope of Channelized Flow,Sw: 0.06408 ft/ft Conveyance Coefficient2,C5: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA≥0 else CA=0 K c0 =-0.391 +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Co=(CA+C00)/2 K c0 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 K00 =-0.10i +0.11 Return Period) Coompasiie I CA I C5 I C00 I KA I Kco 5-Year 0.136 0.000 0.082 0.163 0.088 0.108 10-Year 0.229 0.069 0.165 0.262 0.167 0.206 100-Year 0.459 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: tor-ti+t, 1=(28.5`Pi,,,)/(10+Tor where P,h,is the 1 hr point rainfall depth or tB=L/180+10(if in urban area) Overland flow travel time equation: to= 62 min Pro, t,=(0.395 (1.1 -C5)`sgrt(Lj))/50.33 4,= 54 min Return Period in in/hr Channelized flow travel time equation: 1, 8 min 5-Year 1.49 1.47 t,L0/(V`60)where V=(C„`Sw°5) V= 3.797 fl/s 10-Year 1.76 1.74 100-Year 2.78 2.75 Peak Flow Rate Rational Method Equation: O=Coomposne*I*A Return Coomoosne I A Q Period in/hr acres cfs 5-Year 0.136 1.47 96.9 19.4 10-Year 0.229 1.74 96.9 38.7 100-Year 0.459 2.75 96.9 122.1 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB13(H3) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 131 acres Basin Imperviousness'(in percent),is 2.0% Distance of Overland Flow,Lo: 2,572 ft Hydrologic Soils Group A Percent of Basin: 29.8% Distance of Channelized Flow,L0: 4,031 ft Hydrologic Soils Group B Percent of Basin: 18.3% Average Basin Slope,S: 0.07733 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 51.9% Slope of Channelized Flow,S„: 0.02720 ft/ft Conveyance Coefficient,C,: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA?0 else CA=0 Kco =-0.391 +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB=(CA+Cco)/2 K00 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.101 +0,11 Return Period' Ccompesee I CA I CB I Cco I KA I Kco 5-Year 0.100 0.000 0.082 0.163 0.088 0.108 10-Year 0.187 0.069 0.165 0.262 0.167 0.206 100-Year 0.394 0.217 0.362 0.507 0.315 0.452 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: ti=t,+t, 1=(28.5'Pie()/(10+Te)°�86 where Pie,is the lhr point rainfall depth or t,=L/180+10(if in urban area) Overland flow travel time equation: te= 74 min PH, t,=(0.395'(1.1 -C5)'sgrt(Lo))/S0.33 ti= 47 min Return Period in in/hr Channelized flow travel time equation: t, 27 min 5-Year 1.49 1.30 t,Lo/(V'60)where V=(C„'S„.°5) V= 2.474 fVs 10-Year 1.76 1.54 100-Year 2.78 2.43 Peak Flow Rate Rational Method Equation: O=Ccomposae* *A Return Ccomposae I A Q Period in/hr acres cfs 5-Year 0.100 1.30 131 17.0 10-Year 0.187 1.54 131 37.7 100-Year 0.394 2.43 131 125.8 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t, is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB14-1 (1-13) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 62.5 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,Lo: 998 ft Hydrologic Soils Group A Percent of Basin: 39.8% Distance of Channelized Flow,loo: 2,627 ft Hydrologic Soils Group B Percent of Basin: 11.5% Average Basin Slope,S: 0.07844 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 48.8% Slope of Channelized Flow,Sw: 0.05881 ft/ft Conveyance Coefficient2,C,: 15 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA?0 else CA=0 Kco =-0.39i +0.46 Ccu=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ce=(CA+Cco)/2 K 0 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.10i +0.11 Return Period' Ccomv.;re I CA I Co I Cco I KA I KcD 5-Year 0.082 0.000 0.075 0.150 0.090 0.110 10-Year 0.159 0.050 0.150 0.250 0.170 0.210 100-Year 0.364 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: tc=t,+t, 1=(28.5*Pin,)/(10+To)°'e where Pin,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: y 41 min Pm, t,=(0.395*(1.1 -CB)*sgrt(L,))/S033 t,= 29 min Return Period in in/hr Channelized flow travel time equation: t,= 12 min 5-Year 1.49 1.93 tor-Le/(V*60)where V=(C,*S„0 5) V= 3.638 f/s 10-Year 1.76 2.28 100-Year 2.78 3.60 Peak Flow Rate Rational Method Equation: o=Cc,mposne*I A Return Coomo0sne I A Q Period in/hr acres cfs 5-Year 0.082 1.93 62.5 9.9 10-Year 0.159 2.28 62.5 22.7 100-Year 0.364 3.60 62.5 82.0 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB15-1 (H5) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 2.7 acres Basin Imperviousness (in percent),is 0.0% Distance of Overland Flow,Lo: 271 ft Hydrologic Soils Group A Percent of Basin: 6.8% Distance of Channelized Flow,Lo: 0 ft Hydrologic Soils Group B Percent of Basin: 0.0% Average Basin Slope,S: 0.00067 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 93.2% Slope of Channelized Flow,Sw: ft/ft Conveyance Coefficient,Cy: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA?0 else CA=0 Kco =-0.39i +0.46 Cco=Kcu+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ce=(CA+Cep)/2 K00 =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.101 +0.11 Return Period( Ccomposae I CA I Ca I CCD I KA I Kco 5-Year 0.140 0.000 0.075 0.150 0.090 0.110 10-Year 0.236 0.050 0.150 0.250 0.170 0.210 100-Year 0.480 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+tr 1=(28.5 Pry)/(10+Te)°)86 where Prh,is the 1 hr point rainfall depth or to=L/180+10(if in urban area) Overland flow travel time equation: t`= 70 min Prh, t,=(0.395'(1.1 -C5)*sqrt(L0))/S°33 t,= 70 min Return Period in in/hr Channelized flow travel time equation: t, 0 min 5-Year 1.49 1.36 1,=L0/(V'60)where V=(C„'Sw°B) V= 0.000 ft/s 10-Year 1.76 1.60 100-Year 2.78 2.53 Peak Flow Rate Rational Method Equation: o=Ccomposue*I`A Return Coomnosao I A Q Period in/hr acres cfs 5-Year 0.140 1.36 2.7 0.5 10-Year 0.236 1.60 2.7 1.0 100-Year 0.480 2.53 2.7 3.3 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum t. is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB16-1 (H5) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 4.2 acres Basin Imperviousness' (in percent),is 0.0 Distance of Overland Flow,Lo: 338 ft Hydrologic Soils Group A Percent of Basin: 6.7% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 0.0% Average Basin Slope, S: 0.00067 ft/fl Hydrologic Soils Groups C&D Percent of Basin: 93.3% Slope of Channelized Flow, S„: ft/ft Conveyance Coefficient2, 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.251 +0.32 CA=KA+(1.31i3-1.44i2+ 1.135i-0.12) for CA≥0 else CA=0 Kw =-0.39i +0.46 Cco=Kss+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB=(CA+Cm)/2 Ka) =-0.18i +0.21 For 5-yr Storm Return Period: K A =-0.08i +0.09 Ka) =-0.101 +0.11 Return Period' Ccomposae I CA I CB I Ccn I KA I Kco 5-Year 0.140 0.000 0.075 0.150 0.090 0.110 10-Year 0.237 0.050 0.150 0.250 0.170 0.210 100-Year 0.480 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: 1= 28.5*P /(10+T)o.re6 where P is the 1 hrpoint rainfall depth Lesser of: k=t;+t, ( 'Dina e m, P or tc=L/180+10(if in urban area) Overland flow travel time equation: te= 78 min Pm, t;=(0.395*(1.1 -C5)*sgrt(L0))/5a33 t,= 78 min Return Period in in/hr Channelized flow travel time equation: t1 0 min 5-Year 1.49 1.26 t,Le/(V*60)where V=(C„*5„6 6) V= 0.000 ft/s 10-Year 1.76 1.49 100-Year 2.78 2.35 Peak Flow Rate Rational Method Equation: Q=Cwmpo,ue*I*A Return Ceomposne I A Q Period in/hr acres cfs 5-Year 0.140 1.26 4.2 0.7 10-Year 0.237 1.49 4.2 1.5 100-Year 0.480 2.35 4.2 4.7 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB17(H5) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 11.8 acres Basin Imperviousness' (in percent),is 0.0% Distance of Overland Flow,Lo: 411 ft Hydrologic Soils Group A Percent of Basin: 19.9% Distance of Channelized Flow,Le: 0 ft Hydrologic Soils Group B Percent of Basin: 0.0% Average Basin Slope, S: 0.00067 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 80.1% Slope of Channelized Flow,S„,: ft/ft Conveyance Coefficient,Cy: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.4412+ 1.135i-0.12) for CA≥0 else CA=0 Kco =-0.39i +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 CB=(CA+CCD)/2 Kco =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08/ +0.09 Kco =-0.10/ +0.11 Return Period' Ceompo:ae I CA I CB I CcD I KA ' Kco 5-Year 0.120 0.000 0.075 0.150 0.090 0.110 10-Year 0.210 0.050 0.150 0.250 0.170 0.210 100-Year 0.440 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: to=t,+tr l=(28.5'Plh,)/(10+Te)°'86 where Pr n,is the lhr point rainfall depth or t,=L/180+10(if in urban area) Overland flow travel time equation: te= 88 min Pm, I L=(0.395 (1.1 -C5)'sgrt(L0))/Sa33 t,= 88 min Return Period in in/hr Channelized flow travel time equation: t1= 0 min 5-Year 1.49 1.16 t, Le/(V'60)where V=(Cy'S„,05) V= 0.000 ft/s 10-Year 1.76 1.37 100-Year 2.78 2.16 Peak Flow Rate Rational Method Equation: o=Ce�wene'I'A Return Coemposne I A Q Period in/hr acres cfs 5-Year 0.120 1.16 11.8 t6 10-Year 0.210 1.37 11.8 3.4 100-Year 0.440 2.16 11.8 11.2 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 Parsons Mine - Lafarge West, Inc Preliminary Drainage Report Peak Runoff Calculations Using the Rational Method Basin: RB18-1 (1-16) Condition: Reclaimed Storm Return Period: Basin Chracteristics Area,A: 1.1 acres Basin Imperviousness' (in percent),is 0.09O Distance of Overland Flow,Le: 147 ft Hydrologic Soils Group A Percent of Basin: 0.0% Distance of Channelized Flow,Lc: 0 ft Hydrologic Soils Group B Percent of Basin: 0.0% Average Basin Slope,S: 0.00496 ft/ft Hydrologic Soils Groups C&D Percent of Basin: 100.0% Slope of Channelized Flow,Sw: ft/ft Conveyance Coefficient',C,: 5 Runoff Coefficient Runoff Coefficient Equations For 100-yr Storm Return Period: KA =-0.25i +0.32 CA=KA+(1.31i3-1.44i2+1.135i-0.12) for CA 0 else CA=0 K00 =-0.39i +0.46 Cco=Kco+(0.858i3-0.786i2+0.774i+0.04) For 10-yr Storm Return Period: KA =-0.14i +0.17 Ce=(CA+Cu))/2 Kco =-0.18i +0.21 For 5-yr Storm Return Period: KA =-0.08i +0.09 Kco =-0.10i +0.11 Return Period, Ccomposue I CA I CB I Cco I KA I Ku) 5-Year 0.150 0.000 0.075 0.150 0.090 0.110 10-Year 0.250 0.050 0.150 0.250 0.170 0.210 100-Year 0.500 0.200 0.350 0.500 0.320 0.460 Time of Concentration Rainfall Intensity Total time of concentration equation: Rainfall Intensity Equation: Lesser of3: tc=t;+1i l=(28.5*P,r,.)/(10+T,)°MB where P,,,,is the 1 hr point rainfall depth or tc=L/180+10(if in urban area) Overland flow travel time equation: t,= 26 min t=(0.395"(1.1 -C5)*sgrt(Lj))/S°h3J ti= 26 min Return Period in in/hr Channelized flow travel time equation: t,= 0 min 5-Year 1.49 2.54 q=1_,/(V"60)where V=(C, Sw°5) V= 0.000 ft/s 10-Year 1.76 3.00 100-Year 2.78 4.74 Peak Flow Rate Rational Method Equation: o=Ccomposne"I"A Return Ccomposne I A Q Period in/hr acres cfs 5-Year 0.150 2.54 1.1 0.4 10-Year 0.250 3.00 1.1 0.8 100-Year 0.500 4.74 1.1 2.6 Notes: 1: Basin imperviousness determined from guidelines in UDFCD Drainage Criteria Manual Table RO-3 2: Conveyance coefficient determined from guidelines in UDFCD Drainage Criteria Manual Table RO-2 3: Minimum to is 10 min.for non-urban areas and 5 min.for urban areas Date: 9/18/2009 APPENDIX C ADJACENT PROPERTY OWNERSHIP . 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",,I;•••••\ lJ ti Parsons Mine Permit Extent ,_f� . = `4a�*�,� ��,t r'� r�° ^\�._ \ c 'I �� Contributing Drainage Area :, c• !( -�. \ �\\ . x � eel ti , � ` \ \` 1� • ' \ —FI `\` _.• : c .f' 1 %~ :: � __—_— •7SJ <0<: Fig No. 11) DEERE & AULT Parsons Mine Vicinity Map CONSULTANTS , iNC= . Job No. (Scale: 1 :48 ,000 Il II r J R67W 66WID \ : N • . III •. ‘.... I i ---C•t--- ......."....'......'el — • .. . r III It f L11 rt ' . 1-11 1- ,. �r ti 1 .�[ yl;'7 1 1 • r r Ill { I fT , it f .. •Pt ..�,y , 1 c 4. 21 IW•N T r I — l,.� . - l — �,"fie w J -• yy 4 i 119 r. f"'L) rl ,� 1 �� rial*Cir , . . it..., a es L T V , i. }� 1 I_ ., -I'- .• R- c - • it 'I01 . . .„, \. _ �:r. , k A -'' I r f .s:-4 P • ! V t - ..41 Na Mir 1 C. ,. - Cache la Po r fe RiVe'r : ' '' • ` . - 04 �e Iv , , I at r ' • \ , �[; 4 . a- J,` fi V , .4 - :, . # H3_` �'� -- ,...:3 it L1 l AY NS _ ...,, , . T611 `J;tr ire ,/: .. •II ,•I ^-! ; �. , ' \'‘).-.,, YtCu ...�� jr-J. '+ ..1s:‘, 1 \ 1 i • `-. % i - .,,,atHor -Timis; 4(F:tit..., III 4 61,44: '‘ �, • ' �'a e.— 1 /._ ter CParsons Mine Permit Extent , ` ` LO •.490 ! 980 1 ,470 1 ,960 2,450 is Historical Subbasins -_ I Feet li I__u__I.-.' :f Parsons Mine Fig No. C DEERE & AULT L T Historical Drainage Subbasins 2 a cowsu ><. >I ANT' S . 1NC . Job No. Scale: 1 : 14,000 EXHIBITS Ste, akrsizad mops ie. ors wt4 Ws. Hello