Fact Sheet
Attachment 1
Improving Water Quality:
TMDLs in Oregon
Background
Oregon’s rivers, streams and lakes are a valuable
resource for the state. Not only do they provide
great natural beauty to Oregon, but they also
supply the water necessary for drinking water,
aquatic life, recreation, industry, and agriculture.
With these demands in mind, the Oregon
Department of Environmental Quality (DEQ)
uses a comprehensive approach to maintaining
and improving water quality.
Using a comprehensive approach
Water quality problems in Oregon’s waterways
are nothing new. In 1938, the State Sanitary
Authority (now known as the DEQ) was created
to clean up pollution in the Willamette River
with a focus on regulating end-of-pipe or “point
source” discharges from cities and industry. This
focus continued with passage of the federal
Clean Water Act in 1972. During the last 25
years, as point source discharges have been
regulated, it became more evident that there are
other sources of pollution other than from pipes.
These “non-point” sources come from diffuse
runoff and habitat destruction, and originate both
in urban and rural areas.
Water quality improvement now requires a
comprehensive watershed approach to solving
pollution problems. This reflects the cumulative
effect any activity in a watershed has on overall
water quality. To solve water quality problems in
a stream, river, lake or estuary, we need to
consider the cumulative impact from all
upstream sources including groundwater.
Total Maximum Daily Loads (TMDLs)
Under this new comprehensive strategy to
addressing water quality problems, DEQ looks at
the water quality of the entire river and
watershed rather than whether or not a specific
discharge meets its permit requirements.
DEQ calculates pollution load limits, known as
Total Maximum Daily Loads (TMDLs), for
each pollutant entering a body of water. TMDLs
describe the amount of each pollutant a
waterway can receive and still not violate water
quality standards. TMDLs take into account the
pollution from all sources, including discharges
from industry and sewage treatment facilities;
runoff from farms, forests and urban areas; and
natural sources such as decaying organic matter
or nutrients in soil. TMDLs include a safety
margin for uncertainty and growth that allows
for future discharges to a river or stream
without exceeding water quality standards.
In the past, rivers and streams may have had
several different TMDLs, each one determining
the limit for a different pollutant. With its new
comprehensive approach, DEQ takes into
account all pollutants entering a waterbody and
develops TMDLs that will control all pollutants
in a particular geographic area, such as a
watershed or sub-basin.
The process for establishing a plan to improve
water quality begins when the waterbody
appears on DEQ’s 303(d) list, which lists
waterbodies that do not meet water quality
standards.
Water Quality Division
Watershed
Management Section
811 SW 6th Avenue
Portland, OR 97204
Phone: (503) 229-6345
(800) 452-4011
Fax:
(503) 229-6037
Contact: Dick Pedersen
www.deq.state.or.us
Developing water quality plans
Federal law requires that streams, rivers, lakes
and estuaries that appear on the 303(d) list be
managed to meet state water quality standards.
In most cases, rivers and streams receive
discharges from both point" and non-point
sources of pollution.
DEQ’s comprehensive watershed approach for
protecting water quality includes developing
TMDLs for both point and non-point sources.
DEQ is committed to having federally approved
TMDLs on all waterbodies listed on the 1998
303(d) list by the end of the year 2007. This
time frame takes into account the urgency to
save declining salmon runs, the desire of
landowners to begin working on restoration
efforts, and the desire of communities to
safeguard their drinking water sources.
Sediment from eroding banks is carried downstream and
can impact fish habitat and agriculture.
Last Updated: March 2001
By: Dick Pedersen
When establishing TMDL limits, DEQ:
 Reviews existing data and monitors to
determine what pollutant is causing water
quality problems and in what amounts it is
entering the water. The review and
monitoring also attempts to determine how
much of the pollution comes from point
sources, non-point pollution, such as surface
runoff, and how much is naturally
occurring.
 Uses techniques such as computer models to
determine what affect the pollution is having
on the stream or river, and how much of the
pollutant can be discharged without
exceeding water quality standards in the
watershed.
 Uses this information to establish permit
limits on the amount of pollutant each pipe
can discharge and limits on non-point
sources that are controlled through various
water quality management plans.
This comprehensive approach focuses on
watershed plans developed locally.
How plans are developed
Management plans to restore streams and rivers
to water quality standards will be developed by
government agencies in cooperation with
landowners.
 If the land adjacent to a waterbody is
agricultural, then the Oregon Department of
Agriculture would work with the
landowners in the watershed to devise and
implement a management plan (as stipulated
by Senate Bill 1010).
 If the land is private or state forest, then the
Oregon Department of Forestry implements
the Forest Practices Act.
 Federal agencies (such the U.S. Forest
Service or the Bureau of Land Management)
would have responsibility to develop
watershed management plans for federal
lands.
 In urban and rural areas not covered by other
state or federal agencies, cities and counties
would develop management plans, working
closely with local watershed councils.
These plans are sent to DEQ for inclusion in an
overall water quality management plan, which
DEQ then submits to the U.S. Environmental
Protection Agency (EPA) along with the TMDL.
EPA has the responsibility for approving the
TMDL.
Not all basins will have TMDLs developed at
once. DEQ has prioritized the order for
allocating resources to develop TMDLs through
the year 2007.
Protecting our future
Through careful planning and through such
approaches as the Total Maximum Daily Load,
we can not only address pollution today but also
maintain the quality of Oregon’s waterways for
the future.
For more information about TMDLs, or about
how you can help prevent water pollution, write
the Oregon Department of Environmental
Quality, Water Quality Division, 811 SW Sixth
Ave., Portland, OR, 97204. You may also
contact Dick Pedersen, Watershed Management
Section Manager, at (503) 229-6345.
Further information on TMDLs and other
programs can be found at DEQ’s Web site at
www.deq.state.or.us
This document is available in an alternative
format (e.g. large type or Braille) by calling
DEQ’s Office of Communications & Outreach at
(503) 229-5766 or (toll-free within Oregon) 1800-452-4011. People with hearing impairments
may call DEQ’s TTY line at (503) 229-6993.
Riparian shade is an important component for maintaining
cool stream temperatures.