HomeMy WebLinkAboutAgenda - 05-18-2010-13 (2)Z.nforma+ion =+2m
County of Orange
Department of Environment, Agriculture,
Parks and Recreation
Memorandum
To: Board of County Commissioners
Frank W. Clifton, Jr., County Manager
From: David Stancil, DEAPR Director
Tom Davis, Water Resources Coordinator
Date: May 18, 2010
Subject: Orange Well Net Project
As presented at the Board's January 27, 2009 meeting, a groundwater observation
well network (known as Orange Well Net) comprised of nine bedrock wells and nine
regolith (shallow unconsolidated material) wells is proposed for completion in
Orange County, consistent with the goals of the Water Resources Initiative adopted
by the BOCC in May 2005. At the January 27th meeting, staff was instructed to
search for existing out of use water supply wells to incorporate into the network. As
a reminder, the primary goal of the observation well network is to monitor the natural
stresses on the quantity of groundwater available in storage caused by variations in
climatic conditions. This would be accomplished through the use of regolith
observation wells. The secondary goal of the network is to monitor variations in
groundwater levels in the nine main bedrock lithologies across the county, which
would be accomplished through the use of bedrock observation wells.
Six existing bedrock wells have been identified, evaluated and secured and are now
being utilized in Orange Well Net, as shown on the attached list of wells. Wells
owned by Orange County that have been incorporated include the Rocky Ridge well,
the bedrock well at the Blackwood Farm, and an abandoned well at the Millhouse
Road property. In addition, wells owned by outside organizations were also identified
and evaluated. As a result of this process, Memoranda of Agreement (MOA) with
Duke University, the Eno River Association, and the University of North Carolina at
Chapel Hill (UNC-CH) were completed to permit the county to utilize additional out of
use water supply wells owned by these entities. These MOAs govern the use of a
well in the Blackwood Division of Duke Forest near Eubanks Road, a well on a
parcel of land known as the Eno Confluence Property which is owned by the Eno
River Association, and a well at the former MacCauley Geophysical Laboratory
Environment, Agricutfure, Parks and Recreation
PO Box 8981 / 306-A Revere Road
Hiitsborough, NC 27278
(919) 245-2510
which is owned by UNC-CH. The attached figure illustrates the locations of the six
wells as well as the bedrock geology at these locations.
Once the six bedrock wells described above were secured, instrumentation was
deployed in each of the wells in late March and the collection of groundwater level
data began on March 27th. Hourly groundwater level measurements are being
recorded in each well and this information will be downloaded periodically by staff
from the data loggers. Currently, staff plans to make the groundwater level
information collected in Orange Well Net available to the public via the North
Carolina Department of Environment and Natural Resources- Division of Water
Resources (DWR) Drought Indicator Wells web site:
htto:/1www.ncwater.orglData and Modeling/Ground Water Databases/Drought Indicator Wells/)
This web site includes information for wells located across the entire state and will
permit statistical analysis of the data collected in each of the wells, as shown in the
attached information. Staff intends to establish and maintain links to this information
through the County's H2Orange web site as well as the Department of Environment,
Agriculture, Parks and Recreation web site.
Planning for the inclusion of additional bedrock wells and the implementation of the
regolith well component of Orange Well Net, as originally envisioned, is pending
further funding.
Attachments:
Well location map
List of observation wells
Example of statistical information available from DWR web site
Environment, Agriculfure, Parks and Recreation
PO Box 8181 /306-A Revere Road
Hiflshorough, NC 27278
(919) 245-2510
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Orange Well Net Observation Well Network Bedrock Well Details I
Bedrock Wells
Bedrock Well Location:
Casing
Depth, ft.
Total
Depth, ft.
Cable
Length, ft.
,
Lat.
Long. 4
Elevation,
ft 4
Bedrock Geology
Generalized
Rock Unit
1
Millhouse Rd
67
166
50
35.977137
- 79.077313
796
Epiclastics
2
2
Eno Confluence Property
37
—192'
50
36.136908
- 79.160028
886
Felsic tuff
3
3
Rocky Ridge
67
560
40
35.980190
- 79.137413
969
Felsic lavas and tuffs
Dacite z
4
4
Blackwood Farm
100
302
45
36.018709
- 79.080016
962
Felsic lavas and tuffs
(Dacite)
4
5
UNC Well
21
—237'
110
35.890355
- 79.092693
985
Felsic lutonics- E.
Farrin on Granite a
6
6
Duke Well (Eubanks Rd.)
33 1
—1411 1
40 1
35.967693
- 79.095421
958
Mafic plutonics (Gabbro)
8
1 - Longer tape needed to gauge the depth of these wells.
2 - Main bedrock lithology in the county, by area.
3 - Younger pluton, which may yield higher radon concentrations.
4 - Data from ESRI ArcGIS.
Data Collection began on March 27, 2010.
Source: Tom Davis, Orange County DEAPR