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NONPOINT SOURCE SUCCESS STORY
7em5
Slowing, Detaining and Filtering Stormwater Reduces Bacteria Loads
in the North Concho River
Waterbody Improved High levels of bacteria' nutrients arid low dissolved oxygen
prompted the Texas Commission on Environmental Quality (TCEQ)
to add the North Concho River to the state's list of impairments and concerns in 2008, As early
as 1994, the city of San Angelo (the city) and the Upper Colorado River Authority (UCRA) began
implementing best management practices (BMPs) to slow, detain and filter stormwater entering
the river. The city also conducted nonpoint source (NPS) education and outreach efforts. Beginning
in 2007 to comply with new permit requirements, the city partnered with UCRA to develop a
stormwater management plan (SWMP). A watershed protection plan (WPP) was also developed
in 2008. As a result, water quality in the North Concho River (assessment unit [AU] 1421_08) has
improved, and TCEQ proposed in 2016 to remove the bacteria impairment from the list of impaired
waters.
Problem
The North Concho River is 88 miles long, with a
northwest-to-southeast flow. It flows from Glasscock
County into O.C. Fisher Lake and then through the city
to the confluence of the South Concho River near Bell
Street. AU 1421_08 of the North Concho River is about
6.5 miles long and flows through the city (Figure 1).
Land use in the North Concho River watershed
includes rangeland for livestock grazing, farming and
crop irrigation, concentrated animal feeding opera-
tions, extensive rural subdivision development, and
residential, commercial, and industrial development in
and around the city. In 2017, the estimated population
of San Angelo was 100,000.
The designated beneficial use for AU 1421_08 is pri-
mary contact recreation (PCR). To meet the Texas PCR
water quality standard, Escherichia coli levels cannot
exceed a geometric mean of 126 colony-forming units
per 100 milliliters (cfu/100 mL) of water. AU 1421_08
was found to have geometric means that exceeded
the standard for PCR. As a result, the TCEQ included
AU 1421_08 on the 2008 list of impaired waters. This
segment was listed as impaired for macrobenthos,
and concerns were noted for low dissolved oxygen,
elevated nutrients, total dissolved solids, and excessive
algal growth on the 2002 list of impaired waters.
Figure 1. Map of BMP locations in San Angelo, Texas
Story Highlights
Many parties collaborated to implement BMPs and
conduct watershed planning and education and
outreach in the North Concho River watershed.
Much of the work was completed either before the
city's municipal separate storm sewer system (MS4)
permit was issued in 2008 or was above and beyond
permit requirements after 2008. A Clean Water Act
(CWA) section 319(h)-funded project was initiated in
1994 between the city, UCRA, and TCEQ to restore
North Concho River 1421 08

SWQM Stations
Best Management Practices
 Bank Stabilization
Brush Control
[12412
Detention Pond
Dredging
Education & Outreach
Gabion Retention Structure
Stormwater Cleaning Device

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the North Concho River by constructing BMPsthat
slowed and filtered stormwater before it discharged
to the North Concho River. In 1998, gabion retention
structures designed to reduce stormwater runoff were
constructed at San Angelo's Civic League Park and
Santa Rita Park. These were the first of many struc-
tural BMPs built using CWA section 319(h) funding to
reduce urban runoff and pollutant loading to the North
Concho River.
A wet retention pond at Brentwood Park and a dry
detention pond near 11th Street were constructed in
2001 and 2003, respectively. Monitoring has dem-
onstrated that the Brentwood Park retention pond
can remove 99 percent of total suspended solids,
85 percent of the biochemical oxygen demand and
98 percent of fecal coliform from stormwater. A
gravity-based stormwater cleaning device was also
installed downtown in 2007. After stormwater is
gravity-separated and filtered by this device, effluent
from the system is discharged into the river or pumped
into nearby "living laboratory" demonstration ponds
that are part of the expanded public education effort.
The city encourages homeowners to adopt rainwater
harvesting (RWH) practices to conserve water and
reduce stormwater runoff that contributes bacteria to
waterbodies. The watershed has four RWH systems
on city buildings and at least four RWH systems on
various private commercial buildings. The city does not
track the number of residential RWH systems, but a
conservative estimate is in the hundreds.
The city conducts weekly trash pick-ups at many of
their parks. The city started an Adopt-A-Spot-Program
in 1998. Groups, clubs, families or individuals can
choose to maintain different property locations. In
2017, the program had 51 spots adopted by 78 volun-
teers. The city maintains pet waste stations at parks
along the river to encourage the public to dispose of
pet waste properly.
In 2008 the North Concho River WPP was developed
by the UCRA, with funding from the Texas State Soil
and Water Conservation Board (TSSWCB) via the
U.S. Environmental Protection Agency. The WPP evalu-
ated and assessed potential sources of NPS pollution
and identified control strategies. The city developed a
stormwater management plan for its MS4 in 2008 with
guidance from the UCRA. This led to an education and
outreach campaign to provide the public and private
Concho River SWQM Sites: Bacteria
6250
1250
¦5 250
8/2000
• 12412
15886
—Standard
(126/100mL)
2/2006
7/2011
1/2017
Figure 2. Bacteria levels have dropped in the North Concho
River.
sectors with information on reducing NPS pollution
from their commercial and residential property in the
most vital areas.
Results
The TCEQ originally listed AU 1421_08 on the 2008
list of impaired waters because of high bacteria levels
at TCEQ water quality monitoring stations 12412 and
15886. Water quality data indicate that concentrations
of E. coli have decreased in the North Concho River.
The bacteria levels have been improving at stations
12412 and 15886 (Figure 2). During the 2016 assess-
ment, the E. coli geomean for AU 1421_08 was below
the 126 cfu/100 mL PCR use standard, resulting in the
waterbody's proposed removal from the impaired
waters list.
Partners and Funding
Watershed partners have spent approximately
$3,928,263 on water quality improvements in the
North Concho River, combining $2,358,958 in CWA
section 319(h) funds with $1,569,305 matched by
local efforts. Of these combined funds, the TCEQ
granted $1,983,718 with $1,322,478 from local match,
for a total of $3,306,196. The TSSWCB provided
$375,240 with $246,827 from local match, for a total
of $622,067. Private funding for NPS water quality
improvements on the North Concho River included a
contribution of $260,000 in 1997 from a private bene-
factor. The city of San Angelo also collects a half-cent
sales tax implemented in 1999, which helped fund this
project.
^edsj^ U.S. Environmental Protection Agency
0** Office of Water
^ Washington, DC
WJ
EPA 841-F-19-001E
PROt^° J a n u a ry 2019
For additional information contact:
Tim Cawthon, Texas Commission on Environmental Quality
512-239-0845 • tim.cawthon@tceq.texas.gov
Brian Koch, Texas State Soil and Water Conservation Board
979-532-9496 • bkoch@tsswcb.texas.gov

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