HomeMy WebLinkAboutAgenda - 01-27-2009 - 4 ORANGE COUNTY
BOARD OF COMMISSIONERS
WORK SESSION AGENDA ITEM ABSTRACT
Meeting Date: January 27, 2009
Action Agen
Item No.
SUBJECT: Observation Well Network Project
DEPARTMENT: Environment and Resource PUBLIC HEARING: (YIN) No
Conservation
ATTACHMENT(S): INFORMATION CONTACT:
Powerpoint Presentation Handouts Thomas W. Davis, 960-3878
FY 2009-19 CIP Cost Estimates David Stancil, 245-2590
PURPOSE: To provide the Board with an update regarding the plans for the Orange County
Observation Well Network, and to receive feedback from the Board on the proposed project.
BACKGROUND: Groundwater is the sole source of water for approximately 40 percent of the
residents of Orange County. Orange County has a history of proactive measures regarding the
investigation and protection of surface water and groundwater resources. A Water Resources
Committee was first organized in the County in early 1992 in conjunction with a multi-year
Water Resources project. This project featured cost-share cooperation with the United States
Geological Survey (USGS) on the production of three technical publications regarding
groundwater quantity and quality issues in the County. Upon completion of the studies, the
Water Resources Committee issued its Report of the Water Resources Committee in March,
2001. In the cover letter to the committee report, Chair Don Cox noted several key points
including: "...the committee recommends that the county institute a long-term program of well
measurements that can provide information as to the effects of land use changes and climatic
changes on the availability of ground water. The USGS data (the reports mentioned above)
gives us a base line of information that can be useful into the future with the addition of a good
monitoring program."
Subsequently, the Orange County Commission for the Environment produced the Water
Resources Initiative in early 2005. This report was adopted in principle by the BOCC in May
2005, and included three main areas for further investigation: Droughts and Floods, Ground-
Water Contamination, and Resource Evaluation, Public Service and Education. The first goal in
the Droughts and Floods section was: "Planning and creation of an observation well network to
increase available ,knowledge and data about the impact on ground water supplies from
drought." Additionally, the first goal included in the Ground-Water Contamination section was:
"Further research on elevated radon findings in some ground water samples from the United
States Geological Survey studies of 1996/2001."
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The observation well network that is now being planned for the County will address these issues
as well as others including recent work exploring the relationship between bedrock lithology
(geology) and arsenic content in groundwater.
The stated goals of the Observation Well Network, consistent with the Water Resources
Initiative adopted in 2005, are as follows:
A. Monitor impact of drought on groundwater levels across the County, i.e., to work as an
"early warning system" and permit monitoring of groundwater quantity county-wide.
B. Conduct further delineation of groundwater base flow, which is the contribution of
groundwater to streams. This would provide useful information regarding the amount of
groundwater which feeds surface water reservoirs in the County.
C. Enable further research into groundwater quality issues, including elevated radon and
arsenic concentrations detected in groundwater during previous investigations in the
county. Elevated radon concentrations were detected by Cunningham and Daniel in their
2001 report entitled Investigation of Ground-Water Availability and Quality in Orange
County, North Carolina. This report documented radon activity in groundwater ranging
from 38 to 4,462 picoCuries per liter (pCi/L), and a median groundwater concentration of
405 pCi/L in Orange County. The proposed Federal MCL (maximum contaminant level)
for radon is 300 pCi/L if no statewide or local EPA approved multimedia mitigation
program exists, with an alternative proposed MCL of 4,000 pCi/L if an approved
multimedia mitigation program is in place. The 2001 report of Cunningham and Daniel
also identified some correlation between bedrock lithology and radon concentration.
Arsenic concentrations in groundwater in this area of the Piedmont have been documented by
several researchers, and the North Carolina Geological Survey has recently worked to establish
links between arsenic concentrations and certain bedrock lithologies in Orange County.
A groundwater level measurement program as described above is only possible with a
dedicated groundwater observation well network. Periodic sampling of observation wells in
identified areas to research radon and arsenic content in groundwater, as well as other
groundwater quality issues, will also be possible. Partnerships in the development and
utilizations of the network are possible with local Federal and State agencies. Fortunately
collaboration with local scientists interested in exploring aspects of groundwater quality and
quantity issues in the County is also anticipated as a result of the establishment of the network.
In addition, some existing wells on County-owned or leased property appear to be good
candidates for the network, thus lowering the over-all cost of the network. Guilford County has
an observation well network and Wake County is developing a network for similar reasons.
FINANCIAL IMPACT: Funds for this project are included in the CIP for the next three years.
Opportunities for partnering with interested State and Federal agencies may also be possible
and are being aggressively explored by staff. The amount of funding for the first year of the
program is proposed for $35,000 in FY 2009-10 (the program is projected to cost $180,000 over
three fiscal years).
RECOMMENDATION(S): The Manager recommends the Board receive the presentation
concerning the Observation Well Network project and provide feedback and guidance to staff
for further refinement of the project plan.
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The Orange County Observation
Well Network
Thomas W. Davis, L. G.
Water Resources Coordinator
Orange County Environment and
Resource Conservation Department
I. Introduction
• Groundwater sole water source for approximately
40 percent of Orange County citizens.
• Surface water supplies are finite and service areas
are unlikely to increase.
• Droughts!!! Don't take supplies for granted.
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II. Background Information
• Water Resources Project (2001)
• Water Resources Initiative (Adopted by BOCC in
2005) identified "Critical Areas to Address",
including:
— Impact of drought on groundwater and surface
water availability.
— Impact of groundwater base flow on water
supplies and aquatic life.
— Further research on elevated radon findings.
Ill. Goals of the Observation
Well Network
• Consistent with items identified by the Water
Resources Project (2001) and the Water Resources
Initiative adopted by the BOCC in 2005, goals are:
1. Groundwater Quantity-"early warning system"
2. Delineation of groundwater base flow.
3. Research groundwater quality, including:
• Radon and arsenic in groundwater.
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IV. Current Situation
• Only two observation wells exist in the County:
• NC-126 USGS regolith (shallow) well on UNC-
CH campus- Needs to be replaced.
• NCDENR-DWR Caldwell bedrock (deeper) well
off Guess Road.
• Guilford County has an observation well network
and Wake County is developing one.
V. Orange County Geology
• Cunningham and Daniel (2001) described the
groundwater system in Orange County as a
"regolith-fractured crystalline rock aquifer system".
A. Regolith
Unconsolidated material which overlies fractured
crystalline bedrock- includes soil, weathered rock,
etc.
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Principal components of the groundwater
system in the Piedmont Province of North Carolina
(from Flamed and Daniel,1992)
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ZONE ,1 , _, OU�D61i
e
NMCIIS®9®NOLS( �`
SNBTJIMR
j SISIICfURE
,
V. Orange County Geology,
cont.
B. Bedrock
Groundwater in bedrock limited by the number and
characteristics of the fractures present.
Bottom Line: Majority of groundwater
storage occurs in the regolith, but
water supply wells utilize water located
in bedrock fractures ("pipelines").
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The reservoir pipeline conceptual model
of the Piedmont groundwater system
(modified from Heath,1984)
WEU.--- Water labia
PtiREGOI.tTHRE5ERUOIR
7APA
p„/,,Q! STORAGE
BEDROCK IN —
AI FRACTURES BEDROCK
//k
V. Orange County Geology,
cont.
• NCGS geologic mapping of Orange County
ongoing. Four main quadrangles complete:
• White Cross, Hillsborough, Efland and
Chapel Hill quadrangles.
• Nine main bedrock lithologies are present
in the recently mapped area of Orange
County.
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VI. Observation Well Design
• Objectives determine well design.
• Observation wells can monitor:
— Natural stresses (drought, terrane differences,
etc)
— Man-made stresses (Over-pumping,
interference, etc)
•
VI. Observation Well Design,
cont.
A. Primary Goal of Observation Well Network:
Monitor natural stresses on the quantity of
groundwater available in storage which are caused
by variations in climatic conditions.
Observation Well Network should mainly utilize
climatic effects (regolith-shallow) observation
wells to monitor groundwater storage response to
variations in climate that occur over time.
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VI. Observation Well Design,
cont.
B.Secondary Goal of Observation Well Network:
Monitor variations in groundwater levels across the
nine main bedrock lithologies.
Terrane effect (bedrock) observation wells
should be completed in each of the nine main
bedrock lithologies.
VI. Observation Well Design,
cont.
• The bedrock wells should also be utilized to gain
water quality information, including:
• Arsenic and radon concentrations in
groundwater
• Groundwater quality near biosolids application
areas
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VII. Summary
• Combination of bedrock and regolith wells
proposed. Wells should be spread across the
County and bedrock wells should be located in
each of the nine main bedrock lithologies.
• Pairs of wells could be installed in the same
locations where possible.
• Network will be able to monitor the quantity of
groundwater in storage as well as monitor
variations in groundwater levels in different bedrock
lithologies.
VIII. Additional Information
• No land purchases are anticipated to be necessary
for the observation well network.
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• Existing wells will be utilized where possible.
• Partners and cooperative arrangements are
possible and should be explored:
— USGS -DWQ(inc. Duke Forest wells)
— DWR -NCGS
— Area Universities-State Climatologists Office
•
• Some school sites may be suitable well locations.
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,0/2,/2046
Capital Project Work Sheet
Project Title Observation Well Network
•
Around 37%of County citizens rely on ground water for their drinking supply.One of the foremost components of the Water Resources Program initiative was the creation of an observation well network,This network would provide
an'early-warning'system regardkrg well levels and water quality,and would enable comparisons of wells In different hydrogeologk areas to gauge and compare the effect of drought on ground water
1.Project Description recharge,and contribution of groundwater lbw to streams.With three drought episodes on the last decade,this Information should help inform citizens and water resources professionals of the Impacts of supplies,recovery levels In
different geographic areas and rock fonnetons in the County.A series of wells would be drilled(including some existing wells on County or other property)and monitored over time to create new Information for the ground water
database.This would be a joint project with the NC Division of Water Quality,USGS and possible other partners.This would be a multi-year project,with efforts to begin b FY 2009-10 to plan and begin setting up the network.
2 Anticipated Project 2012
Completion Date
3.1 Cent on Tax Rate Equivalent I'h 2008.09(NR) 2009,10(R) 201041(NR) 2011.12(NR) 2012-13(NR) 201344(R) 201445(NR) 2015-18(NR) 2016.17(NR) 2017 48(R) 2018-19(NR)
(Projected 1 Cent Equivalent $1,271,729 $1,482,488 $1,508,383 $1,551,554 $1,598,101 $1,837,818 '$1,892,950 $1,949,739 $2,008,231 $2,309,485 $2,378,749
m Based on average annual increases In revenue generated by 1 cent between fiscal years 1998-99 and 2008-09,assumes that assessed property valuation le non-Revaluation years Increases at 3 percent and at 15 percent in Revaluation years.NR=Narreval
Budgeted
4.Project Revenues By Fiscal Year Funding 2009-10 201041 2011-12 201243 2013-14 2014-15 2015.18 201847 2017.18 2018-19 Total Protect
10/01,08 _ Revenues
Pay-As-You-Go Revenues
Per Capital Funding Policy SO. $35,000 $75,000 $70,000 SO_ SO SO $0 $0 SO $0 $180,000
NC Education lottery SO $0 SO $0 SO $0 $0 $0 So . $0 $0 $0
Grants So $0 $0 $0 $0 SO SO SO_
Fees So $0 $ $0 $0 $0 $0 $0 $0 $0 $0 $0
Other SD $0 $0 $0 $0 SO SD $0 So So $0 S9
Total Pay-As-You-Go Revenues $0 835,000 $75,000 $70,000 $0_ $0 SO_ $0 $0 SO $0 $180,000
Proceeds from Currently Programmed Debt
1987 fiords $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
2001 Bonds SO $0 $0 $0 $0 $0 S0 SO $0 $0 $0 SO
2004 213 Net Debt Bonds $0 $0 SO $0 $0 $0 .$0 $0 $0 $0 5o $0
Alternative Financing $0 $0 $0 $0 SO $0$0 $0 $0 So_ $0 $0 $0
tal Proceeds from Currently Programmed Debt SO $0 $0 $0 $0 $0 , $0 $0 $0 , $0 $O $O
Future Debt SO $0 $0 $0 $0 $0 SO $0 $0 $0 $0. $0
Unfunded $0 $0 SO $0 SO $0 SO $0 , $0 So $0 $0
Total Project Revenues $0 $35,000. $75,000_ $70,000 $0 SO $0 SO $0 $0 S0 $180,000
5.Project Appropriations By Fiscal Year
Appropriations Expenditures and AvaSable Total Project
Through 19/01/08 Encumbrances Appropriations 2009-10 2010-11 2011-12 2012-13 2013-14 2014-15 2015-08 2018-17 2017-08 2018.19 ro riatons
Through 1010188 10101108 APP P
LendlBuildkug SO $0 SO S0. SO SO $0 SO SO SO SO SO $0 $0
Purchase
Design SO SO $0 $0 SO $0 SO 10 $O, $0 SO $0 $0 $0
Construction,Repairs, SO SO $0 $35,000 S75,000 $70,000 $0 $0 SO $0 SO SO SO $180,000
Renovations
Other(Equipment,
Furnishings,Artwork, $0 So $0 $0 $0 $0 $0 $0 $0 $0 So $0 $0 $0
etcl
Total Project $0 $0 SO $35,000 $75,000 $70,000 $0 $o $0 $0 $0 $0 $0 $180,000
Appropriations _
64
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