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Executive Summary
Although Total Maximum Daily Loads (TMDLs) appear to have burst upon the
water quality cene over the past several years, they are not a new
concept. TMDLs are simply the implementation of rules included in
Section 303(d) of the Clean Water Act of 1972. However, TMDLs have not
been aggressively and broadly pursued until a series of lawsuits against
EPA began about 10 years ago, compelling EPA and the states to focus on
the TMDL provisions of the Clean Water Act. (For more information on the
quantity and status of the lawsuits, visit EPA’s web site on TMDL
lawsuit information at: http://www.epa.gov/OWOW/tmdl/lawsuit1.html
Today, TMDLs are essentially driving the watershed approach to water
quality management, the perspective that all point and nonpoint sources
of pollution in a watershed – as well as the physical characteristics
of the water body itself – are inextricably linked.
As a result, TMDLs are aimed at managing all sources of pollution which
affect beneficial uses of water, covering both point and nonpoint
sources. Historically, point sources – discharges from single sources
such as wastewater treatment plants or factories – have been most
closely monitored and addressed. TMDLs, and the significant improvements
in reducing point source pollution since the early ‘70s, have now
shifted much of the management focus to nonpoint source pollution,
contamination from diffuse sources on the landscape such as agricultural
runoff, or urban stormwater.
Nonpoint source pollution involves a large and diverse group of agencies
and individuals on urban, agricultural, range, and forested lands. It
forces land and water managers to explore a realm of science that is
little understood and often poorly quantified.
Because we are in the early stages of the TMDL process, it is not always
clear how and where regulations can be imposed on nonpoint sources.
Furthermore, the human and financial resources required for tackling
these issues are immense, though resources are limited.
The general consensus is that there is a scarcity of data on many water
bodies that are suspected to be impaired. Furthermore, more data are
needed to identify sources of nonpoint source pollution within the
watershed. Many state environmental agencies are expanding their staffs
to handle the increasing demands generated by TMDLs, but local expertise
and involvement from environmental agencies, wastewater and drinking
water utilities, conservation districts, federal agencies, schools and
universities, and other sources will play increasingly critical roles in
identifying and solving these problems.
Beyond the science, broad involvement in TMDLs also has sociological
implications. Because TMDLs address all the sources of pollution, from
industrial effluent to fertilizer runoff from homeowner lawns, the TMDL
process requires delicate and dedicated attention to the science and
sociology in each watershed. Every landowner and land user in a
watershed is affected by TMDLs, and broad awareness and involvement are
very important.
There’s a practical side, too. There is simply too much work for any
single group faced with writing and implementing a TMDL. It’s also
clear that all stakeholders will have to work together to develop
comprehensive, holistic approaches to watershed management: piecemeal
approaches are inefficient and will fail in the long run. The magnitude
of TMDLs is a trend that will not only continue, but will likely
increase. Once water quality standards for nutrients are established
(discussed later in this document), the workload could potentially
explode. In short, the challenges on every side of the equation are
numerous.
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