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the areas of fill. The developed area(former drive-in movie theater complex)is
almost entirely paved. Underlying soil types are mapped by NRCS as
predominantly Urban Land,indicating fill material that has no assigned Hydrologic
Soil Group. For the purposes of the hydrologic analyses,soils have been assigned
assumed Hydrologic Soil Groups of"A"and "B." This is based on the documented
' use of the Site,which involved the placement of large amounts of debris,and
consistent vehicular circulation,both of which serve to compact underlying soils and
increase their runoff potential. An NRCS soils map is included in Appendix B.
' Soil test pit investigations,conducted by VHB and supplemented by borings by
Langan Engineering,were conducted across the Site to determine infiltration
potential and seasonal high water table depths. The results of these investigations
indicate that soils are consistently very sandy across the Site with rapid infiltration
rates. Detailed soils information,NRCS soils map,and results of on-site subsurface
' investigations are included in Appendix B.
Hydrologic Information
For the existing conditions hydrologic analysis,the Site was divided into seven(7)
drainage areas that contribute to four(4)design points,where peak discharge rates
were evaluated(see Figure 2).
Design Paint 1 is the northwest property comer,adjacent to the CONRAIL tracks
and the intersection of Chapel Road and John Fitch Boulevard. Two drainage areas
contribute to this Design Point:
> Drainage Area EXIA:This 15.58±acre area is a mix of woods and brush in fair
condition. Runoff from this area flows to an on-site depression where it
infiltrates into the sandy soil. Stormwater that does not infiltrate flows overland
to the swale along the CONRAIL tracks and Drainage Area EMB prior to
reaching Design Point 1.
> Drainage Area EMB:This 26.43+acre contains the remnants of the drive-in
movie theater,including buildings,pavement,woods,gravel,brush and grass.
Runoff from this area flows to an on-site depression where it infiltrates into the
sandy soil. Stormwater that does not infiltrate flows overland to the swale along
the western property line and the CONRAIL tracks(Design Point 1).
Design Point 2 is an existing leaching catch basin located near a property
intersection with Chapel Road. One drainage area contributes to this Design Point:
> Drainage A^, rea EX2:This 0.67±acre area consists of woods,grass,and brush in
fair condition.
' NODATAlpb &k72189,WUepCp5W2inagel 5 Existing Conditions
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