Clean Water Resources
An abundant supply of clean water is essential to our region’s public health and economic
vitality. We drink water, we eat fish that come from it, and we use it for agriculture, industry, and
recreation. Clean water is essential for healthy ecosystems and the native plants and animals that rely on
it. Population growth in our region has increased demand for clean water, while pollution related to
population growth compromises our water supplies.
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.
Many of the region's rivers, lakes, and streams are listed as Category Five impaired and in need of a Total
Maximum Daily Load (TMDL) plan1. A comparison of streams listed as “impaired” in 2006 and those
listed in 2010 show a significant increase. 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. The major threat to the region's drinking and
recreational bodies of water continues to be related to development rates around the capital city of
Raleigh as well as Durham and Chapel Hill. With the Triangle’s population expected to double by 2020,
responsible, low-impact development (LID) needs to be adopted to prevent storm water run-off from new
developments and impervious surfaces.
Educational Element: TLC’s Vision
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 TLC 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.
1
A TMDL is an estimation of the daily maximum of a given pollutant allowed in a body of water.
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.
Educational Element: 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.
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 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.
The Neuse River and the Cape Fear River Basins are two of only four river basins located completely
within the state.
Educational Element:
“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 to 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 day2. 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 well3. To put this in perspective, 150.5 million gallons a
day is enough water to fill 1 million bathtubs every day4.
Figure 1 Where does our drinking water come from? Much of the water we consume comes from neighboring water
supply watersheds.
2
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
3
Calculated for 2005 by summing each county’s average daily domestic-freshwater withdrawals. Source: USGS
Water Use Data
4
Assuming the average bathtub holds 150 gallons of water.
Educational Element: 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 Use
What is this? Water usage is reported by the United States Geological Survey (USGS) every five years
and measured in millions of gallons a day. The region’s water use can be divided into six categories5:
1. Public Supply- water withdrawn by public and private water suppliers that furnish water to at
least 25 people or have a minimum of 15 connections. This supply of water can be used for
domestic, commercial, industrial, or thermoelectric-power purposes.
2. Domestic- water used for indoor and outdoor household purposes, including drinking water,
water for washing clothes or dishes, and watering the lawn. For the purposes of reports prepared
by the USGS, domestic use only includes self-supplied domestic freshwater withdrawals.
3. Industrial- water used for fabricating, processing, washing, diluting, cooling, or transporting a
product; incorporating water into a product; or for sanitation needs within the manufacturing
facility. USGS reports include only the self-supplied industrial withdrawals.
4. Irrigation- water that is applied by an irrigation system to sustain plant growth in all agricultural
and horticultural practices. This also includes the irrigation of golf courses, parks, nurseries, turf
farms, cemeteries, and other self-supplied landscape watering uses.
5. Livestock- water used in livestock watering, feedlots, dairy operations, and other on-farm needs
such as cooling facilities, sanitation, and animal waste disposal. It does not include domestic use
and lawn or garden irrigation.
6. Thermoelectric- water used in generating electricity using steam-driven turbine generators
including self-supplied freshwater or saline water.
5
Source of definitions: USGS Water Use in the United States at http://water.usgs.gov/watuse/
Public Supply, 1985-2005
160
Water Use, (mgd)
140
120
100
80
60
40
20
0
1985
1990
1995
2000
2005
Thermoelectric Water Use,
1985-2005
450
Water Use, (mgd)
400
350
300
250
200
150
100
50
0
1985
1990
1995
2000
2005
Less Intensive Water Use Trends,
1985-2005
Water Use (mgd)
30.00
25.00
20.00
Irrigation
15.00
Domestic
10.00
Livestock
Industrial Use
5.00
0.00
1985
1990
1995
2000
2005
Regional Water Use (mgd), 1985-2005
Category
Thermoelectric
1985
153.53
1990
181.27
1995
391.22
2000
386.58
2005
182.49
Public Supply
70.74
86.53
88.36
135.03
147.46
Irrigation
8.84
16.52
23.42
27.31
22.40
Domestic
18.62
7.93
19.76
20.51
20.48
Livestock
2.08
2.76
7.6
7.40
7.00
Industrial Use
4.32
4.14
12.39
0.49
1.48
258.13
299.15
542.75
577.32
381.31
Total
Table 1 Water Use by Category in order of greatest use in 2005.
What does this measure show? The region’s demand for water has varied greatly between 1985 and
2005 with the largest quantities of water being used for thermoelectric power generation. Other trends
include a steady increase on the amount of water being provided by public suppliers (doubling from 1985
to 2005) and a steady decrease in water being used in irrigation and livestock production, which is
indicative of the urbanizing nature of the Triangle region. A series of plant foreclosures in between 1995
and 2000 is also indicated by the sharp decrease in industrial water use over that time period.
Educational Element: How Can I Conserve Water?
Ten Ways to Reduce Your Water Consumption:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Water your lawn only when it needs it.
Fix leaky faucets and plumbing joints.
Don’t run the hose while washing your car.
Install water-saving shower heads or flow restrictors.
Run only full loads in the washing machine and dishwasher.
Shorten your showers.
Use a broom instead of a hose to clean driveways and sidewalks.
Don’t use your toilet as an ashtray or wastebasket.
Capture tap water.
Don’t water the sidewalks, driveway, or gutter.
By following all of these simple instructions you could save 5,750-7,600 gallons of water per month!
Limitations and Further Research- The greatest limitations with the data reported by the U.S. Geological
Survey is a lack of consistency in the definition of the different water usage categories and that the data is
only collected every 5 years. Due to the definitions of public supply and domestic use it is also difficult to
determine how much water is actually used for domestic (such as drinking water), industrial, irrigation,
livestock, or thermoelectric uses. Local Watershed Plans were also used for the average daily demand
findings which were prepared during different years and therefore had data from different years for each
municipality making an overall estimation of the regional demand for any given year difficult.
Technical Notes- The source for water use category definitions was the USGS Water Use in the United
States Report at http://water.usgs.gov/watuse/. The regional water use table and accompanying graphs
were created by summing the water use in millions of gallons a day for the six counties (Wake, Orange,
Lee, Johnston, Chatham, and Durham) in each water use category for each year. The sums were then
organized in the table in descending order by the amount of water used in 2005. The source of this data
was the USGS Water Use Data by State published every five years from 1985 to 2005.
Water Pollution: Introduction
Water pollution occurs when pollutants are discharged into bodies of water before they are treated. Pointsource 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 sprayed on fields or lawns can wash off and enter
streams and rivers, or soak into the soil and contaminate groundwater.
Pollution can contaminate our sources of drinking water. Pollution of certain chemicals 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.
Finally, instead of measuring environmental conditions directly biological monitoring assesses the health
of aquatic macroinvertebrates. Examples of macroinvertebrates are insects in their larval or nymph life
stage, clams, snails, worms, and crayfish. They are good indicators of stream quality because they can’t
escape pollution and show effects of short and long term pollution events. Macroinvertebrates are an
important part of the stream’s food web, and can show the cumulative impacts of pollution. Certain types
of macroinvertebrates are more sensitive to pollution than others. If sensitive species are missing from a
stream, and few species are present it is an indication that the stream is unhealthy.
Miles of Impaired Stream
What is this? The NC Division of Water Quality assigns a primary classification to all surface waters. All
surface waters must at least meet the standards of Class C waters (fishable/swimmable). Class B waters
have additional standards to meet their use for primary water contact recreation. Waters that are used as
sources of water supply for drinking, culinary, or food purposes have higher levels of protection and are
classed from WS-I to WS-V ranging from undeveloped to highly developed watersheds. There are also
supplemental classifications including Nutrient Sensitive Waters (NSW). NSW need additional nutrient
management due to excessive growth of microscopic or macroscopic vegetation.
When a body of water no longer meets the water quality standards for its designated use it is considered
impaired and may be placed on the 303(d) list. The Clean Water Act requires state to prioritize the
impaired waters on the 303(d) list and to establish total maximum daily loads (TMDLs) for the pollutants
causing the impairment. TMDLs are an estimate of the maximum amount of a pollutant that a waterbody
can take in without violating water quality standards. Once TMDLs are established point sources
discharging the pollutant of interest are assigned waste load allocations in their new permits. In order to
comply with the new permit, some facilities may have to upgrade their treatment technology. TMDLs
also include recommendations of ways to reduce non-point source pollution.
Water quality data that informs the decision to place a stream on the 303(d) list is collected by: Division
of Water Quality ambient monitoring system, NPDES (National Pollutant Discharge Elimination System)
discharge monitoring coalitions, biological assessment unit, North Carolina division of environmental
natural resources division of environmental health, and the U.S. Geologic Survey.
Why is this important? Pollution can contaminate our sources of drinking water and make water unsafe
for recreation. Pollution of certain chemicals 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.
What does this measure show? The map shows streams and shorelines from the 2006 303(d) list, as well
as the proposed 2010 303(d) list, and streams that occur on both lists. For the 2010 list, the most common
parameter of interest is turbidity, followed by copper, ecological integrity, and low dissolved oxygen
(Table 1).
Limitations and Further Research: The 303D list only shows category five impaired waters that require a
total minimum daily load. Category four waters are also considered impaired but already have an EPA
approved total minimum daily load or are in one of the category four descriptions. The 2006 GIS layer
did not contain information on the parameter of interest. It is in the report but it may be difficult to extract
the stats for our region. (I should email to see if they have this in GIS format too)
1
2
Reason for 303(d) 2010 listing
Total Length (Miles)
Figure 1 Map of impaired water from 2006 and 2010 303(d) lists.
Chlorophyll a
17
Copper
163
Ecological/biological Integrity Benthos
144
Low Dissolved Oxygen
86
Low pH
12
NO2+NO3-N
14
PCB
25
Turbidity
368
Zinc
18
All impaired waters (category 5)
847
Educational elements
How does water pollution happen?
Water pollution occurs when pollutants are discharged into bodies of water before they are treated. Pointsource 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 sprayed on fields or lawns can wash off and enter
streams and rivers, or soak into the soil and contaminate groundwater.
How do we test for water pollution?
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.
What are macroinvertebrates and what do they tell us about water pollution?
Finally, instead of measuring environmental conditions directly biological monitoring assesses the health
of aquatic macroinvertebrates. Examples of macroinvertebrates are insects in their larval or nymph life
stage, clams, snails, worms, and crayfish. They are good indicators of stream quality because they can’t
escape pollution and show effects of short and long term pollution events. Macroinvertebrates are an
important part of the stream’s food web, and can show the cumulative impacts of pollution. Certain types
of macroinvertebrates are more sensitive to pollution than others. If sensitive species are missing from a
stream, and few species are present it is an indication that the stream is unhealthy.
Technical Notes
Where the data came from:
GIS layers were downloaded from the division of water quality
http://portal.ncdenr.org/web/wq/ps/mtu/assessment. The 2010 GIS layer is currently being updated, and
hopefully the new layer will be included in our results. The 2006 draft integrated report layer is also from
the same site, but does not include the parameter of interest (POI).
How measured: Length in miles of category 5 impaired water.
Analyses performed; Calculated the total number of miles for each parameter of interest for the draft 2010
303(d) list using calculate geometry in ArcGIS.
Riparian Buffers: Percent Forested, Percent Protected
What is this? Riparian buffers are lands adjacent to streams where vegetation is strongly influenced by
the presence of water. This indicator reports the percent of the riparian buffer (30 meters on each side of
stream) for each county and the entire Triangle region that is forested. The percentage of riparian buffers
that are managed for conservation and open space was also calculated.
Why is this important? Riparian buffers serve a crucial role in promoting good water quality. Buffers help
prevent sediment, nitrogen, phosphorous, pesticides and other pollutants in storm water runoff from
reaching a stream. The woody debris and leaf litter produced by vegetative buffers also provide a major
source of energy and nutrients for stream communities. Overhanging vegetation keeps streams cool which
can be very important for cold-water fish species such as trout.
Heavily vegetated buffers, help maintain stable stream banks and protect downstream property
from flash floods. This allows groundwater to be recharged and sedimentation to be deposited building
stream banks. When buffers are degraded by cutting down or removing vegetation there are many
consequences. In addition to reduced wildlife and fish populations, property damage from flooding and
erosion, loss of valuable agricultural lands, and increased water temperatures, degraded buffers can cause
increased sedimentation, decreased dissolved oxygen, and significant reductions in aquatic stream life.
What does this measure show? Chatham, Lee, and Orange County have the highest percentages of
forested riparian buffer and are above the Triangle region average. Wake County has the lowest
percentage of forested buffer, with only 62%. The Triangle region as a whole has 68% of riparian buffers
in forest cover. 11.6% of riparian buffers are protected in land managed for conservation and open space.
Figure 2 This graph represents the percentage of the total area within the riparian buffer (30 m on either side of stream),
that is forested.
Interpretation against standards: The Neuse River Basin Rules apply to 50ft riparian buffers. Ideally the
region should be striving for completely forested buffers.
Limitations: The land cover layer has a resolution of 30 meters which is approximately 100 feet. This is
not the same distance recommended in the Neuse River Basin Rules (50 feet). However, 100 feet is a
reasonable goal for the width of buffers within the Triangle region.
Educational elements:
What is a Riparian Buffer?
The lands adjacent to streams where vegetation is strongly influenced by the presence of water. They are
also called vegetated buffer zones and are evidence of wise land use management.
Photo by: Kansas Forest Service, http://www.kansasforests.org/riparian/what_is_watershed.shtml
Image by: Paul Lennon, http://live.greeningaustralia.org.au/nativevegetation/pages/page186.html
Technical Notes:
Where the data came from:
Land cover data was from the National Land Cover 2001 Dataset. Stream data was from the Statewide
24K hydrography layer from NC OneMap. Lands managed for conservation and open space were from
NC OneMap.
How measured:
The total area of riparian buffer was divided by the total area of forested riparian buffer, to give the
percent covered in forest. This was done for each county, and the entire Triangle region.
Analyses performed:
All layers were clipped to the six county region. Buffers were created using the ‘Buffer’ tool, with a
distance of 30 meters, side type = full, end type = round, dissolve = all. This was then converted to a
raster with resolution 30m. The land cover was reclassified so that deciduous forest, evergreen forest,
mixed forest, woody wetlands, and herbaceous wetlands were considered ‘forested’. The forested layer
was then extracted by the buffer, and the percentage of forested buffer was calculated for each county,
and the entire region.
REFERENCES
Homer, C. C. Huang, L. Yang, B. Wylie and M. Coan. 2004. Development of a 2001 National Landcover
Database for the United States. Photogrammetric Engineering and Remote Sensing, Vol. 70, No. 7, July
2004, pp. 829-840.
North Carolina Center for Geographic Information and Analysis, 20060210, Statewide 24K hydrography
(polys): North Carolina Center for Geographic Information and Analysis, Raleigh, NC.
NC Center for Geographic Information and Analysis, 20020228, onemap_prod.SDEADMIN.lmcos: NC
Center for Geographic Information and Analysis, Raleigh, North Carolina.
Neuse River Buffer Rules: 15A NCAC 02B .0233 NEUSE RIVER BASIN: NUTRIENT SENSITIVE
WATERS MANAGEMENT STRATEGY: PROTECTION AND MAINTENANCE OF EXISTING
RIPARIAN BUFFERS
http://reports.oah.state.nc.us/ncac/title%2015a%20%20environment%20and%20natural%20resources/chapter%2002%20%20environmental%20management/subchapter%20b/15a%20ncac%2002b%20.0233.html
Water Pollution: Major Dischargers
What is this? Wastewater generally refers to any water that is biologically or chemically contaminated.
Wastewater treatment plants, water treatment plants, and wastewater reclamation facilities as well as
some industries are allowed to discharge cleaned wastewater into surface waters and aquifers as long as it
meets certain standards and they have a NPDES (National Pollutant Discharge Elimination System)
permit. There are limits on how much can be discharged as well as what type and amount of pollutants.
Why is this important? Tracking the number of facilities that have NPDES (National Pollutant Discharge
Elimination System) permits is important because they are major sources of point source pollution.
What does this measure show? Discharges from treatment systems with a flow of 1.0 million gallons per
day or with a pre-treatment program are classified as major discharges. There are 23 major dischargers in
the Triangle region: 11 are wastewater treatment plants, 4 are water reclamation facilities, 1 water
treatment plant, 2 power plants, and 2 private companies. There are 104 minor dischargers in the study
region.
Limitations: Limits for total phosphorus and total nitrogen are normally placed in permits after water
quality tests are performed on the receiving waters. However, there are currently no standards for total
phosphorus or total nitrogen in North Carolina. Additionally, point source pollution makes up only a
fraction of all pollution (point source and non-point source).
Sidebar: Who is required to have a discharge permit? According to the Clean Water Act, any facility
that discharges pollutants into surface waters is required to have a NPDES (National Pollutant Discharge
Elimination System) permit. Typical point sources regulated under the NPDES program include:
-Municipal wastewater systems (e.g. wastewater treatment plants)
-Municipal and industrial storm water systems
-Industries and commercial facilities
-Concentrated Animal Feeding Operations
[NOTE TO REVIEWERS: we are thinking of including a Triangle area map of dischargers as graduated
points based on how much they are allowed to discharge (the greater the discharge, the greater the point).
Based on your experience would this be valuable information to include?]
Water Pollution: Groundwater
Contamination
What is this? Groundwater is important in the Triangle for its agricultural, domestic and industrial uses.
Although groundwater use is largely unrecorded in the Triangle, rural portions of the region are more
reliant upon it as their principal drinking water source. Two principal types of wells are used to measure
groundwater quality: regolith and bedrock monitoring wells. Regolith monitoring wells are shallower and
monitor groundwater levels within the unconsolidated layer above the bedrock, whereas bedrock
monitoring wells measure groundwater levels within the bedrock. There are 5 principal groundwater
wells monitored by the Division of Water Resources and the US Geological Service in the Triangle.
Groundwater contamination can be either natural or man-made, however most sources of
contamination are anthropogenic byproducts: 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.
Why is this important? About 10% of all groundwater public water supply systems are in
violation of drinking water standards because of biological contamination (Citizen's guide to groundwater
protection). Additionally, 74 pesticides, some of them carcinogenic, have been found in the groundwater
of 38 states. Although there have been estimates of the extent of groundwater contamination they have
been difficult to verify because of the nature of the resource and difficulties in monitoring.
The extent of groundwater contamination depends on many factors, including water elevation and
amount of time it takes for the contaminant to reach groundwater levels. Because groundwater moves
slowly and lacks turbulence, once a contaminant reaches it, it forms a concentrated plume that flows at
the same rate as surrounding groundwater. As a result, groundwater contamination incidences can go
undetected for years.
What does this measure show? This measure shows groundwater monitoring wells during the 2006-2008
drought as well as Underground Storage Tank (USTs) incidences (both investigated and “closed out”) for
the six county region. 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 incidences however that the number of incidences
reportedly “closed out” has grown proportionally.
Triangle groundwater levels reached unprecedented lows during the 2006-2008 drought. The Orange and
Wake groundwater monitoring wells respectively experienced a 10 foot and 4 foot drop during the
drought. The Wake County groundwater monitoring well level has consistently ranged between 15 and
20 feet below the surface except when it reached 30 feet below surface in Sept 2007.
Limitations: Reliable data on groundwater is limited because of the lack of monitoring stations and gaps
in the data. Additionally, underground storage tanks are just one source of possible groundwater
contamination6.
County
Well
Type
Year Installed
Data Quality
Orange
Caldwell
Bedrock
1969
Orange
NC-126
1943
Johnston
P381
2004
good
Johnston
Wake
M38Q1
Fuquay Varina
N41G3
Shallow
regolith
Shallow
regolith
regolith
regolith
Data gap
1991-2006
poor
2004
1982
good
Data gap
1991-2001
USGS and Division of Water Resource Groundwater Monitoring Wells in the Triangle
Groundwater Levels During 2006-2008 Drought:
Orange County
6
Johnston County
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.
Wake County Groundwater Levels:
Historic Data
2006-2008 Drought
Number of Underground Storage Tank Incidences in the Triangle
Figure 3 Cumulative number of underground storage tank (UST) incidents, and total closed from 19832009.
[NOTE TO REVIEWERS: Both line graph and bar graph of USTs were included. We didn’t know
whether both should be included. Do you have suggestions for which to include/exclude, or whether you
would display the data differently?]
Case Studies: Jordan and Falls Lake Rules
Jordan Lake
Jordan Lake is one of the Triangle Area’s principle drinking water reservoirs. Its 14,000 acres of water
http://www.ncparks.gov/Visit/parks/jord/main.php serve approximately 460,000 people. Originally
constructed by the Army Corps of Engineers in 1981-82 for flood control, the reservoir now serves as
drinking water supply, recreational site, and wildlife habitat . In 2008, 32% of Jordan Lake’s annual
allocation went to Cary and Apex, doubling from its 1997 allocation. In 2008, allocations also went to
Chatham County (6%), the city of Durham (10%), OWASA (5%), with lesser percentages to Holly
Springs, Morrisville, Orange County, and Wake County- RTP (Jordan Lake Supply Allocation Process
will be one Round 4).
http://www.ncwater.org/Permits_and_Registration/Jordan_Lake_Water_Supply_Allocation/JL4Information-Meeting-2-24-2010-Water-Supply-Allocation.pdf.
Water Quality Concerns
Soon after the lake’s impoundment in 1982 it was declared a Nutrient Sensitive Water by the
Environmental Management Commission (see technical notes), Various sources of pollution affect the
lake. Nutrients from wastewater, runoff from agriculture, and stormwater run-off have led to an increase
in green algae growth during the summer months and potentially toxic algae formation. In 2002 the
Division of Water Quality found that the Upper New Hope Creek arm of the lake was impaired due to
high levels of chlorophyll a, an indicator of drinking water quality. In 2006, the rest of the lake was listed
as impaired. (see technical notes).
The federal Clean Water Act requires that states address waters which have been listed as
impaired. The Clean Water Responsibility Act of 1997 set restoration goals for Nutrient Sensitive Waters.
In 2007 the Jordan Lake rules were published in the North Carolina register, and total minimum daily
levels were approved by the EPA. In May of 2008, the rules were approved by the Environmental
Management Commission, in August 2009 the rules became effective.
The Jordan Lake Rules call for a reduction in phosphorus and nitrogen for each the three arms of
the reservoir. Each arm of the lake is required to reduce nitrogen and phosphorus levels to different
degrees. State law requires that there be a fair and proportionate requirements so each source water in a
given watershed is required to face the same reductions relative to its baseline amounts. The rules address
nutrients from agriculture, storm water runoff from new and developed plans, and wastewater discharges.
In contrast to previous versions of the rules, the new rules address not only nutrients coming from new
development lands but also nutrients coming from existing developments due to their significant
contribution of lake pollution. However, the newest version of the rules have been weakened somewhat
as the revised rules prohibit the Environmental Management Commission from requiring local
governments to retrofit existing development to be in compliance with the rules.
(http://www.thetimesnews.com/news/signs-26284-governor-jordan.html)
Nutrient Reduction Goals: Reduction goals are expressed in terms of a percentage reduction in delivered
loads from the baseline years 1997 – 2001:
Upper New Hope Arm: Reduce the 1997-2001 baseline nitrogen load by 35% (from ~1 million
pounds/year to 640,000 pounds). Reduce the 1997-2001 yearly baseline phosphorus load by 5% (87,245
pounds/year to 82,883 pounds).
The Lower New Hope Arm:Cap the 1997-2001 baseline nitrogen load at ~220,000 pounds per year.Cap
phosphorus load to the 1997-2001 baseline. (26,574 pounds/year)
The Haw River Arm:Reduce the 1997-2001 baseline nitrogen load by 8% (~2,800,000 pounds per year to
~2,600,000 pounds) Reduce the 1997-2001 yearly baseline phosphorus load by 5% (378,569 pounds/year
to 359,641 pounds)
Technical Notes:
A Total Maximum Daily Load, or TMDL, is a calculation of the maximum amount of a pollutant that a
waterbody can receive and still safely meet water quality standards.
Impaired Stream: a body of water which fails to meet state water quality standards for its designated use
as, for example, a recreation site or public drinking water supply.
The Environmental Management Commission is a 19-member Commission appointed by the Governor,
the Senate Pro Tempore and the Speaker of the House. The Commission is responsible for adopting rules
for the protection, preservation and enhancement of the State's air and water resources. Commission
members are chosen to represent various interests, including the medical profession, agriculture,
engineering, fish and wildlife, groundwater, air and water pollution control, municipal or county
government, and the public at large. The Commission oversees and adopts rules for several divisions of
the Department of Environment and Natural Resources, including the Divisions of Air Quality, Land
Resources, Water Quality, and Water Resources. (http://portal.ncdenr.org/web/emc)
Falls Lake
Falls Lake is the most important drinking water supply in the Raleigh area and is one of the
Triangle’s principal reservoirs. It is located north of Raleigh and east of Durham in the Upper Neuse
River Basin and extends across Durham, Wake and Granville Counties. Falls Lake has a 12,500 acre
surface area, receives more than 750,000 visitors per year, and serves approximately half a million with
drinking water. Created in 1983 by the Army Corps of Engineers, the lake is surrounded by 25,000 acres
of public land with four public beaches.
With Durham (20% population increase since 2001) and Raleigh (40% population increase since
2001) its closest cities, Falls Lake is heavily impacted by urban and suburban sprawl. Watershed
development has seriously degraded the lake. The main sources of point-source pollution (e.g. sewage
spills) and non-point pollution (e.g. stormwater runoff, septic tank effluent leachate) in Falls Lake are due
to development of the watershed. In 2008, the NC Division of Water Quality designated the lake as
impaired due to excessive nitrogen and phosphorus levels. During the summer of 2009, there were six
beach closings due to high bacterial counts with E.coli and Enterocci levels well above state standards
and potentially toxic cyanobacteria found throughout the reservoir.
In February 2010 the Water Quality Commission released draft rules for clean-up to ensure that the
lake meet compliance with state and federal water quality standards. The rules are designed to decrease
nutrient levels in the lower portion of the lake (east of Interstate 50) within 10 years and within 30 years
for the more polluted upper portion of the lake. Hearings before the Environmental Management
Commission in Spring 2010 will be held to allow for the public to comment on the rules. The NC
Department of Environment and Natural Resources has until January 2011 to present a final proposal to
the NC legislature for how the lake will be cleaned up.
Debate is on-going over who is responsible for cleaning Falls Lake. Two thirds of Durham County
is found within the Falls Lake watershed however Falls Lake is the principal drinking water reservoir for
Raleigh and most of Wake County (Durham gets its water from Lake Mitchie and Little River Reservoir).
Over the next decade, Durham County projects they will have to pay $20 million but that the cost could
go up to as much as $1 billion were it to upgrade their sewage treatment plant. Raleigh also faces serious
future costs as well. If Falls Lake water quality doesn’t improve by 2016 it will require a $115 million
upgrade to the city’s principle water treatment plant, as well as $200 million in other necessary
improvements - principally due to higher treatment costs from increasing Total Organic Carbon (TOC)
found in Falls Lake. Although phosphorus and nitrate levels are below the federal minimums and Falls
Lake water is safe to drink, increasing treatment costs in the future will only be averted if the lake’s water
quality conditions improve.