United States
Environmental Protection
Agency
n
Total Maximum Daily Loads
Using the TMDL Process to Maintain and Protect Water
TMDL at a Glance
Deer Creek Reservoir Total
Phosphorus
(approved September 2002)
www.waterquality.utah.gov/TMDL/Deer_Creek_Reservoir_
JMDLpdf
Factors causing impairment
Coldwater aquatic life use impaired by low dissolved
oxygen levels at the bottom of the reservoir caused
by excessive phosphorus loads and high surface water
temperatures that affect the reservoir's fisheries
Sources contributing to impairment
Nonpoint source runoff from urban areas and
agricultural activities; a fish hatchery
Restoration options
Implement agricultural best management practices,
cleanup potential concentrated animal feeding
operations, streambank restoration, load reduction
from fish hatchery, and develop comprehensive
nutrient management plans for feedlots casing water
quality impairments
Stakeholder involvement
Wasatch, Salt Lake, and Utah counties, Midway
Fish Hatchery, Jordanelle Reservoir Water Quality
Technical Advisory Committee, five regional
conservancy districts, Utah Department of
Environmental Quality
Status of waternody
Met annual phosphorus load reductions established
by the TMDL to allow for future growth and a margin
of safety during 2006 and 2007; mixed success in
meeting other endpoints established by the TMDL to
maintain good water quality
In 1941, the Bureau of Reclamation completed construction of the Deer Creek Reservoir,
located on the Provo River in Wasatch County, Utah. Since that time, Deer Creek Reservoir
has become a vital source of drinking water for over one million people, as well
as a source of irrigation water and a popular recreation destination. In the 1980s,
concerns over excessive nutrients in Deer Creek Reservoir led to the formation of the
Jordanelle Reservoir Water Quality Technical Advisory Committee (JTAC), the group
responsible for the development of a water quality management plan for Deer Creek
and Jordanelle reservoirs. Although Deer Creek Reservoir at one time did not support
the coldwater fishery beneficial use due to low dissolved oxygen (DO) levels and high
temperatures, analysis of recent data from Deer Creek Reservoir through the TMDL
process revealed that stakeholder efforts led to significant improvements in both
water quality and the health of the reservoir's fishery. Despite these improvements, the
TMDL analysis revealed that DO levels remained a concern under certain conditions.
Too much phosphorus beyond the current loads could lead to algal blooms that
would affect the quality of the drinking water supply and require costly treatment.
As a result, the TMDL for Deer Creek Reservoir established quantifiable targets to
maintain current water quality and identified phosphorus reductions to provide a
margin of safety and allow for future growth in the watershed.
How are TMDLs at work in the Deer Creek Reservoir?
The TMDL process provided stakeholders with a framework for compiling, analyzing,
and understanding data for parameters affecting DO levels in the Deer Creek
Reservoir. The data analysis of factors contributing to the coldwater fishery beneficial
use impairment identified for Deer Creek Reservoir, including dissolved oxygen
levels, temperature, algae levels, water clarity, and fishery health, all showed signs of
improvement at the time of TMDL development. These improvements are attributed
to years of water quality improvement projects and programs. Although the TMDL
development process did reveal improvements in water quality, it also highlighted
the sensitivities of Deer Creek Reservoir. The final TMDL report states that although
major improvements are not needed, it is important to have a plan in place that
stresses protection and management of current conditions — particularly in light of
growth and development pressures in Wasatch County. As a result, stakeholders were
able to participate in the development of a TMDL that establishes quantifiable goals to
maintain current phosphorus loads and identifies phosphorus reductions necessary to
maintain a margin of safety and allow for future growth. The TMDL report estimates
Benefits to stakeholders
Clean water, recreation, aesthetics, economy, funding,
partnerships and education
What is a total maximum daily load (TMDL)?
It is a study or analysis that calculates the maximum amount of a pollutant that a waterbody can receive and still meet
water quality standards. The TMDL establishes a pollutant budget and then allocates portions of the overall budget to
the pollutant's sources. For more information on TMDLs, visit EPA's website at www.epa.gov/owow/tmdl.
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that nine restoration projects, implemented by local, state,
and federal partners, will generate approximately 2,965
kilograms per year (kg/yr) in phosphorus reductions at
a cost of approximately $38,100,000. The TMDL report
estimates that these projects, implemented by local, state,
and federal partners, will generate approximately 2,965
kg/yr in phosphorus reductions at a cost of approximately
$38,100,000.
What is the current status of Deer Creek
Reservoir as a result of the TMDL process?
The 2008 Water Quality Implementation Report for the
Provo River, Jordanelle Reservoir, and the Deer Creek
Reservoir, prepared for the Provo Watershed Council,
provide a summary of the data collected during the 2006
and 2007 water years. Table 1 provides a summary of an
assessment of progress in Deer Creek Reservoir during
2006 and 2007 using the endpoints established through
the TMDL development process as a yardstick.
According to the 2006 and 2007 data, annual phosphorus
loads to Deer Creek Reservoir were below the 15,300 kg/ yr
total load allocation (i.e., current and future allocations
to point sources and nonpoint sources) established in the
TMDL. However, monthly phosphorus loads during the
critical period of August-October exceeded the target
loads set by the TMDL during 2006 and 2007. The data
show that Deer Creek Reservoir met the endpoints for no
fish kills and in-lake phosphorus concentration, but did
not meet the endpoints for DO concentrations in the water
column, trophic state index, and algae biomass.
How did local stakeholders benefit from the
TMDL process?
Through the TMDL process, stakeholders had
the opportunity to claim credit for water quality
improvements in Deer Creek Reservoir and play a role
in establishing the future direction of water quality
management for the reservoir. Striving to achieve the
water quality management goals established in the TMDL
will benefit stakeholders in a number of ways.
O Allowing future growth without sacrificing water
quality. By incorporating pollutant load reductions and
a margin of safety, the TMDL takes into consideration
the growth of Wasatch County without compromising
the quality of the drinking water and irrigation supply.
O Ensuring a high quality drinking water supply
while keeping down treatment costs. Deer Creek
Reservoir is a major source of drinking water for over
one million people, distributed by five separate utilities
located in Salt Lake, Utah, Wasatch, and Summit
counties. Although Deer Creek Reservoir supported
its drinking water designated use at the time of TMDL
development, the TMDL process revealed the sensitive
nature of the reservoir and helped stakeholders set
goals to prevent future drinking water designated use
impairment.
O Improved recreational opportunities and
aesthetics. Maintaining and reducing phosphorus
loads will help to keep Deer Creek Reservoir free from
nuisance algae blooms that can affect recreational
enthusiasts desire to enjoy activities such as
swimming, boating, and fishing on the reservoir.
O Established sustainable, effective partnerships.
The cooperation among partners at all levels,
including UDEQ, JTAC, local communities,
conservation districts, water suppliers, and watershed
groups, have established a strong foundation for
maintaining the water quality of Deer Creek Reservoir
and addressing future issues.
Table 1. Summary of Deer Creek Reservoir Endpoint Assessment for 2006 and 2007
Parameter (Proposed Target)
Percent of the water column with dissolved oxygen concentrations
below the target threshold value to support beneficial use
(<50% of column with DO <4.0 mg/l)
Fish habitat (No fish kills)
In-lake phosphorus concentration (0.025 mg/l TP (Avg all depths))
In-stream phosphorus concentration (0.030 mg/l TP and 0.020 mg/l DTP)
Total Phosphorus loads to lake: Annual (15,300 kg/yr TP and 9,700 kg/yr DTP)
Total Phosphorus loads to lake: August-October
(560 kg/mo TP and 350 kg/mo DTP)
Average Trophic State Index (40-45)
Algae biomass (5.1 ug/l Chlorophyll a; 6.5 x 107 um3/ml Biomass;
3.3 x 1 07 um3/ml Cyanophyta)
Meet Endpoint in 2006?
No
Yes
Yes
Meet Endpoint in 2007?
No
Yes
Yes
[Information on this endpoint not provided
in the 2008 report]
Yes
No
No
No
Yes
No
No
No
For more information on the Deer Creek Reservoir phosphorus TMDL, contact
Dave Wham, Utah Department of Environmental Quality, dwham@utah.gov, (801) 538-6052
For more information on the Utah TMDL Program, visit www.waterquality.utah.gov/TMDL/
&ER&
December 2009
EPA841-F-09-002P
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