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HomeMy WebLinkAboutWPO201600046 Assessment - Groundwater WPO VSMP 2016-08-15 PROJECT MANAGEMENT SHIMP CIVIL ENGINEERING LAND PLANNING ENGINEERING August 15, 2016 Matthew Wentland Albemarle County Community Development 401 Miclntire Road, North Wing Charlottesville, VA 22902 Regarding: HTC Bojangles VSMP Plan WPO 2016-00046 Dear Mr. Wentland, Stormwater management on site is grandfathered as per 4VAC50-60-48.All runoff shall be routed through new culverts and channels into the existing sediment forebays into the regional stormwater detention pond. Per correspondence from Albemarle County, the stormwater pond for the Hollymead PDMC was designed for a maximum impervious cover of 85%. The new development of TM-32-41 D4 has an impervious cover of 73%. The proposed plan meets the stormwater design regulations for this parcel. We have included a land cover map showing this as well as the VDOT Inlet and Culvert design tables for stormwater management on the area of development. If you have any questions please do not hesitate to contact me at: Justinna,shimp-enqineerinq.com or by phone at 434-953-6116. Contents: Site Conditions Map Post-Development Site Conditions Map VDOT Inlet and Culvert Calculations: LD-204 LD-229 NRCS Soil Report e- e - /. O ' . . . . .. : . ., .. . ... . .. . ... . ,. . r e e i4 / CD rlik Pi _-. G m me ....__ •^O I O• [/- C f �,pp n5. m —' O CD N r O 6 / // 1 I Cll W P O CD ro ! CQ j a j D v CI) D m cn °; o �7 I i CD CD c � �� Cl)o ; mCO X Ca _r i 14 o73W _ omp CY CD ° -4> — ZirCC .-r I. CADc f ' O _,\.\\,,,,: ,____z O ` liii c ci)®° fr,%.!. 7 w coo ° 'ill�111;:1j j%�1 ._ II o n Iii° ,�'��i:in "ice o SS lilt I'i1 icy ,, o •l c� 111' 771i 1/i1'"- i�! 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N E 7 C N T (a a) 0. o a LL o L N U) u) a) a - U) N ca O 7 C C 2 N D -O U 2 c- o o J CO $2 o CO -c n o_ lx a Q c N ti m E �a o' _ _ O c Z' a) a) N .)` N a' •O 0 .(0 u) v)2 > O cn � in o a _ co M � < - v Q is m C y (y a O Z aQfa _r. ._ r N # \ coas El w 0 3 F- co U..1 J I . ^ N CQ Q T co ,C CO ca N C O C O a -O a J a y E a) 2 - - c c c ` _ a.2 _ a 3 c0 0' 2 a Lu 0 E n a n A a a 0 d T o o m c co co T a) 0 Q O ca a) al 02 2 2 LL O O a N a) - 1_,_ L O N c a) T N O O v) N Q U u) (n •0 m m O O 0 0 -) CO 2 2 a a' u) u) (n Cl) (7) u) a c u) Q Co Custom Soil Resource Report Map Unit Legend Albemarle County,Virginia(VA003) Map Unit Symbol Map Unit Name Acres In AOI Percent of AOI 27B Elioak loam,2 to 7 percent 1.9 44.6% slopes 28C3 Elioak clay loam,7 to 15 percent 0.1 2.7% slopes,severely eroded 34D Glenelg loam, 15 to 25 percent 2.3 52.7% slopes Totals for Area of Interest 4.3 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils.On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes.Consequently,every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management.These are called contrasting,or dissimilar,components.They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments 8 Custom Soil Resource Report on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps.The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar.Alpha- Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. 9 Custom Soil Resource Report Albemarle County, Virginia 27B—Elioak loam, 2 to 7 percent slopes Map Unit Setting National map unit symbol: kb8y Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost-free period: 195 to 231 days Farmland classification: All areas are prime farmland Map Unit Composition Elioak and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Elioak Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down-slope shape: Convex Across-slope shape: Convex Parent material: Residuum weathered from mica schist Typical profile H1 -0 to 8 inches: loam H2- 8 to 39 inches: silty clay H3-39 to 79 inches: silt loam Properties and qualities Slope: 2 to 7 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 6.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: B 28C3—Elioak clay loam, 7 to 15 percent slopes, severely eroded Map Unit Setting National map unit symbol: kb91 10 Custom Soil Resource Report Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost-free period: 195 to 231 days Farmland classification: Not prime farmland Map Unit Composition Elioak and similar soils: 80 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Elioak Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down-slope shape: Convex Across-slope shape: Convex Parent material: Residuum weathered from mica schist Typical profile H1 - 0 to 8 inches: clay loam H2- 8 to 39 inches: silty clay H3-39 to 79 inches: silt loam Properties and qualities Slope: 7 to 15 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.20 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low(about 6.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B 34D—Glenelg loam, 15 to 25 percent slopes Map Unit Setting National map unit symbol: kb9m Mean annual precipitation: 25 to 65 inches Mean annual air temperature: 54 to 59 degrees F Frost-free period: 195 to 231 days Farmland classification: Farmland of statewide importance Map Unit Composition Glene/g and similar soils: 80 percent 11 Custom Soil Resource Report Estimates are based on observations, descriptions, and transects of the mapunit. Description of Glenelg Setting Landform: Hillslopes Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down-slope shape: Convex Across-slope shape: Convex Parent material: Residuum weathered from mica schist Typical profile H1 -0 to 8 inches: loam H2-8 to 28 inches: silty clay loam H3-28 to 80 inches: loam Properties and qualities Slope: 15 to 25 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: High Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: High (about 9.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B 12 References American Association of State Highway and Transportation Officials(AASHTO).2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials(ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt,G.W.,and L.M.Vasilas,editors.Version 6.0,2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/soils/?cid=nres 142p2_054262 Soil Survey Staff. 1999. Soil taxonomy:A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http://www.nrcs.usda.gov/wps/portal/ nres/detail/national/soils/?cid=nres142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http://www.nrcs.usda.gov/wps/ portal/nres/detail/national/soils/?cid=nres142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nres.usda.gov/wps/portal/nres/detail/soils/ home/?cid=nres142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 13 Custom Soil Resource Report United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nres/detail/soils/scientists)?cid=nres142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nres.usda.gov/wps/portal/nres/detail/national/soils/? cid=nres142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf 14