Catawba-Wateree Groundwater Network
Project Number: 2519-DDR01
Project Chief: Bruce Campbell
Cooperator: Centralina Council of Governments and Catawba Wateree Water Management Group
Period of Project: October 1, 2008 to September 30, 2011
Project in collaboration with the USGS North Carolina Water Science Center
INTRODUCTION
Catawba-Wateree River Basin and groundwater-level monitoring site locations. The recent multiyear drought in North and South Carolina (summer 1998-fall 2002) made critical the recognition of the vulnerability of the water resources in these two States to climatic conditions. To prepare for drought conditions in the future, water managers and State and Federal water-resource agencies are seeking tools to assess hydrologic conditions in both a predictive and responsive manner. Monitoring networks of near real-time streamflow gages (surface-water stage/discharge) and wells (ground-water levels) are essential components typically used to assess hydrologic conditions.
The Catawba River originates in North Carolina and flows east and south into South Carolina. Downstream of the Lake Wateree Dam the river name changes to the Wateree River. For this proposed study, the Catawba River Basin (CRB) is defined upstream as tributaries to Lake James in North Carolina, and downstream at the Lake Wateree Dam in South Carolina. Currently (May 2005), nearly 50 surface-water gages (more than half in Mecklenburg County, NC) are operated by the USGS in the CRB of North and South Carolina, while only 5 wells are part of the USGS and State agency ground-water networks. The groundwater component of the hydrologic cycle is often overlooked in basin wide water-resource monitoring. Ground water provides base flow to streams and is the primary streamflow component during drought conditions, and seasonally when rainfall/runoff is less frequent. Understanding the relations between ground water and surface water is essential to efficient management of the resources by water-supply planners.
BACKGROUND
During the recent drought (1998-2002), releases of water from the reservoirs required careful planning to maintain water-supply and in-stream flow requirements. The Catawba River flows through 9 counties in North Carolina and 5 counties in South Carolina. The Catawba-Wateree basin includes 13 hydropower stations and 11 surface-water reservoirs operated by Duke Energy. Major reservoirs in the CRB are Lake James, Rhodhiss, Hickory, Lookout Shoals, Norman, Mountain Island, Wylie, Fishing Creek, and Wateree. These hydropower stations provide more than 800 megawatts of electricity and water supply for more than 1 million people in North Carolina (North Carolina Division of Water Resources, 2001). The Catawba-Wateree Federal Energy Regulatory Commission project license was issued in 1958 and is scheduled for renewal in 2008.
As part of the FERC relicensing process, stakeholder groups that include more than 160 representatives from 97 different organizations are meeting to address common regional interests of citizens, river and lake keepers, fishermen, recreational boaters, property owners, industries, and State and Federal resource agencies (http://www.dukepower.com/community/lakes/cw/; accessed May 2005). As an outcome of numerous stakeholder meetings, a “Catawba-Wateree Agreement-in-Principle (AIP)” was drafted. Attachment G within the AIP entitled, the “Low Inflow” of the AIP draft includes a section entitled, “Recovery from the Low Inflow Protocol (LIP) for the Catawba-Wateree Project”. Ground-water levels were identified as an essential component for determining hydrologic conditions. The goal of determining critical levels for ground-water conditions are to assist Duke Energy toward the assessment of impending onset, or recovery from, drought conditions. Determination of critical ground-water levels for the CRB is inherently difficult because of the lack of long-term ground-water level data for the CRB. A long-term data set generally is needed to determine the magnitude of climatic effects on ground-water levels. Data collected from the newly constructed wells will be compared to existing long-term ground-water levels data from wells outside of the CRB.
Because of near real-time data-collection capabilities and experience with long-term data collection, the United States Geological Survey (USGS) was asked to design and construct a ground-water monitoring network for the CRB. This document contains descriptions of tasks proposed for the construction of a CRB ground-water network in North and South Carolina using existing USGS drilling capabilities and resources from ongoing cooperative USGS-State agency and national programs.
Site 5 well drilling. OBJECTIVE
The objective of this study is to construct a ground-water-level monitoring network for the CRB to assist water managers in assessing hydrologic conditions, particularly during times of drought. The constructed wells (20 well clusters of two wells each) will be instrumented with near real-time water-level monitoring equipment with data available every hour via USGS web pages. These water-level data can be used to establish critical “trigger” levels for ground-water conditions, as part of the CRB water-resource monitoring effort. Scientists from both the USGS, Duke Power, and stakeholder groups will work together in an effort to assess hydrologic conditions and determine critical ground-water levels for the CRB.
APPROACH
Because of the large study area and diverse hydrogeologic settings, 10 monitoring well stations are suggested to attain areal proximity to the 4 major reservoirs (Lake James, Norman, Wylie, and Wateree) and cover the regional geologic units (belts). Seven of the ten sites would be well clusters, including both regolith and bedrock wells, while the remaining five sites would consist of only regolith wells. One cluster site (number 6) is already established in North Carolina. Nine new ground-water stations will need to be constructed as part of this proposed study. A few existing wells (1 regolith (site number 6) and 3 bedrock wells (site numbers 6, 7, and 8) will be utilized. Drilling activities proposed as part of this study will consist of the construction 9 new regolith wells (6 in NC; 3 in SC) and 4 new bedrock wells.
The first 3 to 6 months of the study will focus on the selection and access of drilling sites (table 2). Well-drilling locations will be selected based on their proximity to surface-water reservoir, designated regional geologic unit, and logistical access (including appropriate permits). Base flow analyses of available surface-water discharge data may be conducted to determine areal differences of ground-water contribution related to regional geologic unit. Each individual well-cluster drilling site also will be located outside of the influence of the surface-water reservoir (topographically higher than flood plains, or river terrace deposits) to obtain representative ground-water level data.
As the new wells are constructed, near real-time ground-water-level monitoring instrumentation will be installed. Raingages will be added if data are not available from other agencies. These data will be transmitted to the USGS Water Science Centers in North and South Carolina and made available to the partners on USGS web pages every hour. Data will be quality assured in accordance with USGS NC and SC Water Science Center Ground-Water Quality Assurance Plans.
DATA LINKS
Real-time data for the sites shown in the site location map at the top of this page are available at:
- Site 1: Pleasant Gardens
- Site 4: Lancaster County Airport
- Site 5: Lake Wateree
- Site 6: Langtree Peninsula at Lake Norman
- IR-130 LANGTREE RS MW-2S NR MT MOURNE (Regolith well)
- IR-131 LANGTREE RS MW-2I (Transition zone well)
- IR-132 LANGTREE RS MW-2D (Quartz diorite well)
- Site 7: Linville Research Station
- Site 8: Glen Alpine Research station
- BK-126 GLEN ALPINE RS (Bedrock well)
- BK-127 GLEN ALPINE RS(Shallow well)
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U.S. Geological Survey