HomeMy WebLinkAboutSWAP13.1
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In t r o d u c t I o n
The Federal Safe Drinking Water Act (SDWA) Amendments of 1996 emphasize pollution prevention as an important strategy
for the protection of ground and surface water resources. This new focus promotes the prevention of drinking water
contamination as a cost-effective means to provide reliable, long-term and safe drinking water sources for public water
supply (PWS) systems. In order to determine the susceptibility of public water supply sources to contamination, the
amendments also required that all states establish a Source Water Assessment Program (SWAP). Specifically, Section 1453
of the SDWA Amendment requires that states develop and implement a SWAP to:
Delineate source water assessment areas;•
Inventory potential contaminants in these areas; and •
Determine the susceptibility of each public water supply to contamination. •
In North Carolina, the agency responsible for the SWAP is the Public Water Supply (PWS) Section of the DENR Division
of Environmental Health (DEH). The PWS Section received approval from the EPA for their SWAP Plan in November
1999. The SWAP Plan, entitled North Carolina’s Source Water Assessment Program Plan, fully describes the methods and
procedures used to delineate and assess the susceptibility of more than 9,000 wells and approximately 207 surface water
intakes. To review the SWAP Plan, visit the PWS website.
de l I n e at I o n o f So u r c e Wa t e r aS S e S S m e n t ar e a S
The SWAP Plan builds upon existing protection programs for ground and surface water resources. These include the
state’s Wellhead Protection Program and the Water Supply Watershed Protection Program.
W e l l h e a d Pr o t e c t i o n (WhP) Pr o g r a m
North Carolinians withdraw more than 88 million gallons of groundwater per day from more than 9,000 water supply wells
across the state. In 1986, Congress passed Amendments to the SDWA requiring states to develop wellhead protection
programs that reduce the threat to the quality of groundwater used for drinking water by identifying and managing
recharge areas to specific wells or wellfields.
Defining a wellhead protection area (WHPA) is one of the most critical components of wellhead protection. A WHPA
is defined as “the surface and subsurface area surrounding a water well or wellfield, supplying a public water system,
through which contaminants are reasonably likely to move toward and reach such water well or wellfield.” The SWAP uses
the methods described in the state’s approved WHP Program to delineate source water assessment areas for all public
water supply wells. More information related to North Carolina’s WHP Program can be found on the DEH website.
W a t e r Su P P ly Wat e r S h e d Pr o t e c t i o n (WSWP) Pr o g r a m
DWQ is responsible for managing the standards and classifications of all water supply watersheds. In 1992, the WSWP
Rules were adopted by the EMC and require all local governments that have land use jurisdiction within water supply
watersheds adopt and implement water supply watershed protection ordinances, maps and management plans. SWAP
So u r c e Wa t e r a S S e S S m e n t o f Pu b l i c Wa t e r
Su P P l i e S (SWaP)
13.2
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uses the established water supply watershed boundaries and methods established by the WSWP program as a basis to
delineate source water assessment areas for all public water surface water intakes. Additional information regarding the
WSWP Program can be found on the DWQ website.
Su S c e p t I b I l I t y de t e r m I n at I o n - no r t h ca r o l I n a ’S ov e r a l l ap p r o a c h
The SWAP Plan contains a detailed description of the methods used to assess the susceptibility of each PWS intake in
North Carolina. The following is a brief summary of the susceptibility determination approach.
ov e r a l l Su ScePtibility ra t i n g
The overall susceptibility determination rates the potential for a drinking water source to become contaminated. The
overall susceptibility rating for each PWS intake is based on two key components: a contaminant rating and an inherent
vulnerability rating. For a PWS to be determined “susceptible”, a potential contaminant source must be present and
the existing conditions of the PWS intake location must be such that a water supply could become contaminated. The
determination of susceptibility for each PWS intake is based on combining the results of the inherent vulnerability rating
and the contaminant rating for each intake. Once combined, a PWS is given a susceptibility rating of higher, moderate
or lower (H, M or L).
i n h e r e n t vu l n e r a b i l i t y ra t i n g
Inherent vulnerability refers to the physical characteristics and existing conditions of the watershed or aquifer. The
inherent vulnerability rating of groundwater intakes is determined based on an evaluation of aquifer characteristics,
unsaturated zone characteristics and well integrity and construction characteristics. The inherent vulnerability rating
of surface water intakes is determined based on an evaluation of the watershed classification (WSWP Rules), intake
location, raw water quality data (i.e., turbidity and total coliform) and watershed characteristics (i.e., average annual
precipitation, land slope, land use, land cover, groundwater contribution).
co n ta m i n a n t ra t i n g
The contaminant rating is based on an evaluation of the density of potential contaminant sources (PCSs), their relative
risk potential to cause contamination, and their proximity to the water supply intake within the delineated assessment
area.
i n v e n t o r y o f Po t e n t i a l co n ta m i n a n t So u r c e S (PcSS)
In order to inventory PCSs, the SWAP conducted a review of relevant, available sources of existing data at federal, state
and local levels. The SWAP selected sixteen statewide databases that were attainable and contained usable geographic
information related to PCSs.
So u r c e Wa t e r pr o t e c t I o n
The PWS Section believes that the information from the source water assessments will become the basis for future
initiatives and priorities for public drinking water source water protection (SWP) activities. The PWS Section encourages
all PWS system owners to implement efforts to manage identified sources of contamination and to reduce or eliminate
the potential threat to drinking water supplies through locally implemented programs
To encourage and support local SWP, the state offers PWS system owners assistance with local SWP as well as materials
such as:
Fact sheets outlining sources of funding and other resources for local SWP efforts.•
Success stories describing local SWP efforts in North Carolina.•
Guidance about how to incorporate SWAP and SWP information in Consumer Confidence Reports (CCRs).•
Information related to SWP can be found on the DEH website.
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pu b l I c Wa t e r Su p p ly Su S c e p t I b I l I t y de t e r m I n at I o n In t h e br o a d rI v e r ba S I n
In April 2004, the PWS Section completed source water assessments for all drinking water sources and generated reports
for the PWS systems using these sources. A second round of assessments were completed in April 2005. The results of
the assessments can be viewed in two different ways, either through the interactive ArcIMS mapping tool or compiled in
a written report for each PWS system. To access the ArcIMS mapping tool, simply click on the “NC SWAP Info” icon on the
PWS website. To view a report, select the PWS System of interest by clicking on the “SWAP Reports” icon.
In the Broad River Basin, 249 public water supply sources were identified. Eight are surface water sources, one is a
groundwater source under the influence of surface water and 240 are groundwater sources. Of the 240 groundwater
sources, 237 have a Higher susceptibility rating and 3 have a Moderate susceptibility rating. Table 13-1 identifies the eight
surface water sources, the groundwater water source under the influence of surface water and their overall susceptibility
ratings. It is important to note that a susceptibility rating of Higher does not imply poor water quality. Susceptibility is
an indication of a water supply’s potential to become contaminated by the identified PCSs within the assessment area.
ta b l e 13-1: SWaP re S u l t S f o r Su r f a c e Wa t e r So u r c e S in t h e br o a d ri v e r ba S i n
PWS id
nu m b e r
in h e r e n t
vu l n e r a b i l i t y
ra t i n g
co n ta m i n a n t
ra t i n g
ov e r a l l
SuScePtibility
ra t i n g
na m e o f Su r f a c e
Wa t e r So u r c e
PWS na m e
0123010 H L M FIRST BROAD RIVER CITY OF SHELBY
0123020 M L M MOSS LAKE TOWN OF KINGS MOUNTAIN
0123055 H L M FIRST BROAD RIVER CLEVELAND CO SANITARY
DIST
0175010 H L M BIG FALLS CREEK TOWN OF TRYON
0175010 H L M FORK CREEK TOWN OF TRYON
0175010 H L M COLT CREEK TOWN OF TRYON
0181010 H L M SECOND BROAD RIVER TOWN OF FOREST CITY
0181035 H L M BROAD RIVER BROAD RIVER WATER
AUTHORITY
0181106 H L M SPRING #1 CHIMNEY ROCK PARK