HomeMy WebLinkAboutSUB200700310 Review Comments Groundwater Assessment 2007-10-25Tier II Groundwater Assessment
TMP 28 - 30A
Application Number: SUB200700310
Groundwater Reviewer: J. Rubinstein
Date: 25 October 2007
Description: 1 division — 2 lots
Site Description
In a groundwater assessment done for the Albemarle County, ENSAT
Corporation divided the county into `hydrologic units'. Below is ENSAT's
description of the unit containing the parcel:
The Colluvial Fan unit lies at the base of the eastern slopes of the Blue
Ridge Mountain and is characterized by relative steep drainage swales
that extend to more gradual sloping conditions. The area includes a
series of intermittent drainages that include ephemeral drainage ways.
Many of the intermittent drainages become perennial streams as this
area includes stream bottom valleys. A significant portion of the unit
area consists of transported soils including the Braddock and
Thurmont. These soils are formed in colluvial and alluvial materials
found on colluvial fans and terraces and are the product of weathered
granite, granodiorite, granite gneiss, and greenstone. Both of these
soil series are deep and well drained with slopes ranging from 2 -25 %.
Residual soils including the Hayesville and the Chester are also
abundant. These soils are also deep and well drained and are formed
on upland slopes from weathered products of granite and granite
gneiss. Slopes of these soils typically range from 2 -45 %. The
accumulation of transported soils (colluvial and alluvial) can form
"cappings" over residual soils and parent material, which can add to
the overall thickness of the overburden.
According to the Virginia Department of Mineral Resources 1993 Map, the
bedrock beneath most of the parcel is in the charnockite of the Blue Ridge
Basement Complex (Ycm).
The site is in the Moormans River watershed.
Buffers
According to the county GIS site, along the eastern boundary and most of
the northern portion of the lot is within a required buffer for Ward Creek, its
tributary and the 100 year flood plain.' The parcel is within the watershed
for the South Fork of the Rivanna public water supply reservoir. It is not
within the reservoir's buffer.
Water Quantity
The Albemarle County Database shows ten wells within half a mile of the
lot. The wells range from 32 to 325 feet in depth with a mean depth of 236
feet. The well yields range from zero to twenty gallons per minute with a
mean yield of eight gallons per minute.
Water Quality
As shown on the Virginia Department of Environmental Quality (DEQ) GIS
website, there are two leaking underground storage tank sites (LUST) within
a mile.2 Both are closed cases but one.
1 http: / /gisweb.albemarle.org/
2 http: // gisweb. deq .virginia.gov /deqims /viewer.htm ?SERVICE= VA_DEQ