Groundwater


 * Water Indicators**
 * //Fresh Water Supply//** :: Water Use
 * //Water Pollution//** :: Miles of Impaired Streams :: Riparian Buffers :: Major Dischargers :: Groundwater Quality and Quantity
 * //Case Studies//** :: Jordan Lake Rules :: Falls Lake Rules

=Groundwater=


 * What is this?**

This indicator reports on the quality and quantity of groundwater in the Triangle region. Groundwater is an important water source for domestic, industrial and agricultural uses. Almost 7% of the region's population is reliant upon groundwater as its public supply; however, public supply accounts for only 17% of total groundwater withdrawals. Private groundwater wells (self-supplied, domestic wells) account for over 50% of the region's groundwater withdrawals.

The US Geological Survey monitors thousands of wells nationwide (either remotely, or through field tests) for chemical, physical and biological parameters. Within the Triangle region, The NC Department of Environment and Natural Resources Division of Water Resources and the US Geological Survey principally monitor 5 groundwater wells. Groundwater contamination can be either natural or man-made, however most sources result from the activities of humans: hydrocarbons and synthetic organic chemicals (e.g. solvents, pesticides, petroleum), leachates (from Superfund or landfill sites, for example), heavy metals or organic decomposition products. Sources of groundwater contamination are myriad, the principal being: septic tanks, surface impoundments, agricultural activities, landfills, underground storage tanks, abandoned wells, and accidents or illegal dumping.


 * [[image:clipped_well.jpg width="575" height="382"]] || [[image:toxic-waste-barrels.jpg width="576" height="386"]] ||
 * Photo Source: http://www.egsconsultants.com/projects.html || Photo Source: http://www.allamericanpatriots.com/photos/waste-drums ||


 * Why is this important?**

=
Maintaining an adequate supply of clean groundwater is essential to the overall health of the Triangle's water supply. Contaminated groundwater can eventually reach surface waters (e.g. from abandoned wells) just as polluted surface waters can seep through soils to reach groundwater.======
 * What does this measure show?**

This measure reports on Underground Storage Tank (USTs) incidents (both investigated and "closed out") as an indicator of groundwater quality. Underground storage tanks, of which there are between five and six million in the U.S., are primarily used to store gasoline and fuel oil. Although the average life span of each unit is 18 years, units degrade due to environmental exposures. The data indicate that there has been a gradual increase in the number of Underground Storage Tank incidents across the six county region between 1983 and 2009 but that the number of these incidents investigated and "closed out" has increased at a similar rate (Figure 1). , with the greatest number of incidents in Wake County (~1,600 incidents). however that the number of incidents reportedly “closed out” has grown proportionally.
 * Groundwater Quality Indicator**

and total closed from 1983-2009. ||
 * = [[image:UST_ALL_SITE.jpg width="480" height="360"]] ||= [[image:UST_SITE.jpg width="486" height="368"]] ||
 * Figure 1: Number of Underground Storage Tank Incidences in the Triangle || Figure 2: Cumulative number of underground storage tank (UST) incidents,

This measure reports on countywide groundwater data and USGS groundwater monitoring well data. Triangle groundwater levels reached unprecedented lows during the 2006-2008 drought. The Orange and Johnston County groundwater monitoring wells respectively experienced a 10 foot and 4 foot drop during the drought (Figures 3 and 4). The Wake County groundwater monitoring well level has consistently ranged between 15 and 25 feet below the surface except when it reached 30 feet below surface in Sept 2007 (Figures 5 and 6).
 * Groundwater Quantity Indicators**

Figure 3: Orange County Well (Caldwell) During Drought Years || Figure 4: Johnston County Well (P38) During Drought Years ||
 * [[image:Orange_County_well_during_Drought.jpg width="231" height="169"]]

(Fuquay Varina N4163). || Figure 6: Wake County Groundwater Data during 2006-2008 Drought. (Fuquay Varina N4163) ||
 * [[image:Historic_Groundwater_Levels_Wake_County.jpg width="236" height="193"]] || [[image:Wake_County_Drought_Groundwater_Levels.jpg width="236" height="187"]] ||
 * Figure 5: Historic Wake County Groundwater Data


 * Table 1.** Groundwater Monitoring Wells in the Triangle. Source: USGS and Division of Water Resources


 * Limitations and Further Research**

Reliable data on groundwater is limited because of the lack of monitoring stations and gaps in the data (Table 1). Additionally, underground storage tanks are just one source of possible groundwater contamination.Other potential sources of groundwater contamination: Above Ground Storage Tanks ([|ASTs] ), Superfund sites (both NC State and National Priority List Sites), RCRA Hazardous Waste (Generators/Transporters, Transport, Storage, Disposal [|TSD] ) Sites, [|Old Landfill Sites], Polychlorinated Biphenyl (PCB) Sites, Septage Disposal Sites, Solid Waste Facilities, Permitted Biosolids Application Sites, and [|Brownfields Sites].


 * Author** Brunell Gugelmann, North Carolina State University :: 2010 April 27
 * Reviewers** Tom Davis, Water Resources Coordinator, Orange County :: Amy Pickle, Duke University


 * Technical Notes**

Statistics on Groundwater use were obtained from the USGS's Water Use in the United States- [|County Level Data] (2005) Website Groundwater data was obtained from [|USGS Groundwater for the Nation] using the following parameters: DAILY STATISTICS/ Site Selection Criteria: STATE/TERRITORY, Site type: WELL, Available parameters: ALL, Output Format: Table of sites sorted by SITE NUMBER grouped by COUNTY. Parameter Name: DEPTH TO WATER LEVEL, FEET BELOW LAND SURFACE. Output Format: Tab separated data by YYYY-MM-DD (display in browser). Files were then imported into Excel. Excel File:

Information on Underground Storage Tank (UST) Incidences was obtained from the N.C. Division of Waste Management's [|Underground Storage Tank Section] website. Click on [|UST Program], then under "Incident Management Database" click [|Excel]

Water Indicators
 * //Fresh Water Supply//** :: Water Use
 * //Water Pollution//** :: Miles of Impaired Streams :: Riparian Buffers :: Major Dischargers :: Groundwater
 * //Case Studies//** :: Jordan Lake Rules :: Falls Lake Rules