Clean 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


An abundant supply of clean water is essential to our region’s public health and economic vitality. We need fresh drinking water, eat fish that live in local streams and lakes, and use water for agriculture, industry, and recreation. Clean water is essential for healthy ecosystems and the native plants and animals that rely on these ecosystems. Clean water is critical for supporting natural ecosystems and population growth in our region. It is, however, being threatened by pollution related to expanding development in the region.

Summary of findings: The Triangle Region has one of the highest development rates in the nation, which has had dramatic impacts on the region's principal rivers, lakes, and other major water bodies. According to U.S. Census Bureau population estimates, approximately 40 people moved into the region every day between year 2000 and year 2008. In conjunction with this population growth, the demand for publicly supplied water in the region is steadily increasing with an average of 147 million gallons of water being used daily in 2005 (an increase of 12 million gallons daily since 2000). Complicating the issue of providing drinking water for the region's growing population is the increasing level of impairment of water supply watersheds.

Many of the region's rivers, lakes, and streams are listed as Category Five impaired and in need of a Total Maximum Daily Load (a calculation of the maximum amount of a pollutant that a waterbody can receive and still safely meet water quality standards). A comparison of streams listed as “impaired” in 2008 and those listed in 2010 show a decrease in the length of impaired waters in the region (see Miles of Impaired Streams for additional information). Progress has been seen in the development of rules to curb pollutant levels entering Jordan Lake, one of the region’s principal drinking water reservoirs, and negotiations are on-going to develop rules for Falls Lake. One of the major threats to the region's drinking and recreational bodies of water continues to be related to development rates in the region, especially around the capital city of Raleigh as well as Durham and Chapel Hill. With the Triangle’s population expected to double by 2020, it has been recommended that responsible, low-impact development be adopted to reduce storm water run-off from new developments and impervious surfaces.


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Photo Source: http://www.enr.state.nc.us/dswc/images/Neuse_River.jpg
Photo Source:www.scdhec.gov/environment/water/dwoutreach.htm


Triangle Land Conservancy’s Vision

The Triangle Land Conservancy envisions a Triangle Region in which the supply and demand for clean water are balanced at levels that can be sustained for people, plants,
and animals. TLC will support clean water by:

  • Conserving land along streams to protect natural pollution filtration systems.
  • Managing Triangle Land Conservancy lands to keep soil and pollutants out of streams and encouraging public and private landowners to do the same.
  • Working collaboratively with public and private partners to protect water supplies.


Triangle River Basins

The Triangle Region is principally found within the Neuse River and Cape Fear River Basins, with all of Chatham and Lee counties falling within the Neuse River Basin and Orange, Durham, Wake and Johnston counties falling within both river basins.
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watersheds.jpg
Major North Carolina drainage basins.
Source:http://nc.water.usgs.gov/realtime/images/north_carolina.jpg

What is a River Basin?

A river basin is the portion of land drained by a river and its tributaries. It encompasses all of the land surface dissected and drained by many streams and creeks that flow downhill into one another, and eventually into one river. The final destination is an estuary or an ocean. There are 17 river basins in North Carolina, draining 52,337 square miles of surface and underground waters. The Neuse River and the Cape Fear River Basins are two of only four river basins which are located completely within the state.

Facts about the Neuse River Basin:
The Neuse River Basin is the third largest river basin in North Carolina (6,235 square miles) and encompasses all or portions of 18 counties and 77 municipalities. The population of these 18 counties increased by 27 percent from 1990 to 2000 and is expected to increase by 44 percent between 2000 and 2020. The population within this area is projected to grow by more than 867,000 with the total number of people living within the Neuse River Basin to be over 2,000,000 by 2020
.

Facts about the Cape Fear River Basin:
The Cape Fear River Basin is the largest river basin in North Carolina (9,149 sq. miles) and includes portions of 26 counties and 115 municipalities. The basin is composed of five major drainages: Haw River, Deep River, Northeast Cape Fear River, Black River and the Cape Fear River.


What is the difference between a river basin and a watershed?

Both river basins and watersheds are areas of land that drain to a particular water body, such as a lake, stream, river or estuary. In a river basin, all the water drains to a large river. The term watershed is used to describe a smaller area of land that drains into a smaller stream, lake or wetland. There are many smaller watersheds (called sub basins and sub-watersheds) within a river basin. The Neuse River Basin contains 14 sub basins, half of which are found within the Triangle Region. The Cape Fear River Basin contains 24 sub basins, 13 are found within the Triangle Region.


Introduction to Freshwater Supply

An adequate supply of drinking water to meet the needs of the region’s growing population is a great concern for local municipalities and water service providers. The average daily demand for water supplied by the region’s 27 utility providers is approximately 130 million gallons a day (1). As shown by the map below, this water is often piped long distances from surface water sources such as Falls Lake and Jordan Lake to homes and businesses within each municipality. In addition to the public supply of drinking water, another 20.5 million gallons a day of domestic freshwater withdrawals are extracted through private sources usually in the form of a well (2). To put this in perspective, 150.5 million gallons a day is enough water to fill over 1.5 million bathtubs every day (3).
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Where does our drinking water come from? Much of the water we consume comes from neighboring water supply watersheds.
Raleigh's Water Supply Watershed (WSW) comes from Falls Lake, which is being encroached upon by Durham's expanding development (in blue).
Durham's Water Supply Watershed (WSW) is primarily from Lake Michie and the Little River Reservoir (in green).

Where does our water come from?

Drinking water can come from either ground water sources (via wells) or surface water sources (such as rivers, lakes, and streams). Nationally, most water systems use a ground water source (80%), but most people (66%) are served by a water system that uses surface water. This is because large metropolitan areas tend to rely on surface water, whereas small and rural areas tend to rely on ground water.
In addition, 10-20% of people have their own private well for drinking water. The majority of the Triangle Region’s drinking water comes from its two reservoirs- Falls and Jordan Lakes.


Water Pollution

Water pollution occurs when pollutants are discharged into bodies of water. Point-source pollution comes from a discrete source such as a pipe or drain. Examples of point sources are factory discharges and sewage treatment plants. Non-point source pollution is contamination from a large source area. Fertilizer or pesticides that have been applied to fields or lawns can wash off and enter streams and rivers, or soak into the soil and contaminate groundwater.


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Photo source: http://www.epa.gov/owow/nps/categories.html

Pollution can contaminate our sources of drinking water. Nutrient pollution from fertilizers and other sources can cause harmful algal blooms that reduce oxygen levels, killing fish and other wildlife. Other pollutants such as mercury and PCBs accumulate in the tissue of the fish we catch, making them unhealthy to eat.

Water pollution is measured using physical, chemical, and biological methods. Chemical methods can test for pH, nutrients, dissolved oxygen (DO), metals (including copper, lead, and mercury), and pesticides. Physical tests measure temperature, total suspended solids, and turbidity. Turbidity is a measure of how much the suspended materials in water decrease the clarity of water.


Technical Notes

1. Calculated by averaging the Average daily Demand for each month for each of the utility providers and summing for the region as a whole. Source: Sarah Bruce with the TJCOG and Don Rayno from the most recent Local Watershed Planning data.

2.Calculated for 2005 by summing each county’s average daily domestic-freshwater withdrawls. Source: USGS Water Use Data.

3. Assuming the average bathtub holds 150 gallons of 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