Your browser does not support modern web standards implemented on our site
Therefore the page you accessed might not appear as it should.
See www.webstandards.org/upgrade for more information.

Whatcom Watch Bird Logo


Past Issues


Whatcom Watch Online
What Is a “TMDL” and Why Should You Care?


August 2008

What Is a “TMDL” and Why Should You Care?

by Wendy Harris

Wendy Harris is a Bellingham resident and a community activist with an interest in environmental law.

“TMDL” is short for “Total Maximum Daily Load” and refers to the results of water pollution studies for a waterbody. If you live in the Lake Whatcom watershed, or are among approximately 50 percent of the Whatcom County residents who rely on the lake for drinking water, you may have already heard this term being discussed because an official TMDL report should be released for Lake Whatcom in the next month or two. The draft TMDL report was issued in April.

For those not in the Lake Whatcom watershed, a TMDL may be coming to your watershed in the future. A TMDL may have an impact on your taxes, your current lifestyle and the priority and focus of city and county projects.

This article attempts to provide a broad and very general overview of the TMDL process. The procedure and laws in their entirety, which are complex and beyond the scope of this article, can result in some variation with regard to a specific TMDL. You can find more information about the TMDL process and specific TMDLs, on the Washington State Department of Ecology (“Ecology”) Web site at http://www.ecy.wa.gov/programs/wq/links/wq_assessments.html.

TMDLs require a complicated interplay of actions at the federal, state and local level. Statutory authority for TMDLs exists in the Clean Water Act (CWA), the primary federal law governing water pollution, which is under the jurisdiction of the Environmental Protection Agency (“EPA”).

The TMDL studies are analyzed and reflected in a report issued by the state. The municipalities with jurisdiction over the waterbody obtain input from local citizens and create a water cleanup plan. Frequently, TMDL studies indicate that water quality could be restored if existing programs are implemented and existing regulations enforced.

As part of the TMDL process, each state determines the designated uses of a waterbody. Examples of designated uses in Washington include recreation, fish habitat, drinking water and irrigation. States then establish water quality standards that are appropriate for each designated use. These standards are a crucial part of the TMDL process.

Beginning this year, the Washington State Department of Ecology, which oversees the TMDL process, lists waterbodies under one of five categories recommended by EPA. A waterbody is placed in Category 5 when data indicates that it is too polluted to meet water quality standards, and thus, is impaired for its designated use. Category 5 waters are placed on the EPA’s impaired waters list, also known as a 303(d) list, which triggers a TMDL.

The TMDL determines what pollutants are entering a waterbody, where they are entering, the source of the pollutants and how this impacts the ecological function of the waterbody.

The maximum amount of a pollutant that can be discharged and still meet water quality standards is known as the pollutant load. The pollutant load typically includes a margin of safety, considers seasonal variations in water quality and may allow for anticipated growth. The pollutant load is allocated among the different parties who contribute to the pollution.

The CWA addresses “point source” and “nonpoint source” pollution, and handles each differently. Point source pollution is discharged by a specific polluter directly into water, often through pipes and drains (think of it as “pointing” directly to the factory or waste treatment plant discharging pollution.)

When the CWA was first enacted in 1972, a primary focus was on point source pollution, which is regulated under the National Pollutant Discharge Elimination System (NPDES) permit program. The CWA was amended to include additional municipal and urban area storm water programs within its permit system.

The CWA also manages nonpoint pollution, now considered the primary source of water pollution, through non-regulatory programs that encourage voluntary compliance with best management practices. Nonpoint source pollution occurs when rainfall, snowmelt or irrigation sweeps pollution, such as lawn and crop fertilizers, pet waste, pharmaceuticals, spilled boat fuel or faulty septic tank seepage, into waterbodies.

The sources of nonpoint pollution are diverse and not easily identified, but are in large part connected to the loss of pervious surfaces resulting from development, which reduces the amount of run-off absorbed into soil.

It has been asserted that because the CWA does not regulate nonpoint source pollution, it lacks enforcement power. However, enforcement authority exists under Washington state law. Under RCW 90.48, it is illegal to pollute waters of the state and Ecology is authorized to take enforcement actions against polluters, including imposition of stiff fines and incarceration.

Moreover, local governments have strong incentive to implement a TDML water cleanup plan because this increases their eligibility for grants and low cost loans.

Once the TMDL studies are completed, Ecology issues releases a draft TMDL report to the municipalities with jurisdiction over the impaired waterbody. These local governments review the draft TMDL and provide input to Ecology.

For example, a draft TMDL report concerning Lake Whatcom was issued to Whatcom County and the city of Bellingham this April. Ecology reviews and addresses the questions and concerns raised by the local governments and then releases an official TMDL report. This process can take several months or more.

Once the official TMDL report is issued, the public comment and review period begins. Pollutant loads, allocations and other determinations can be revised during this comment period based on differing interpretations of facts and the meaning of test results, as well as political pressure. The goal of the TMDL process is to create a water cleanup plan, also known as a “TMDL Response Plan,” to improve water quality.

While the water cleanup plan is determined at the local level, the final version of the TMDL report is drafted by Ecology, and sent to EPA for approval.

A water cleanup plan may involve new capital facilities and programs that require an increase in local taxes and fees. It may place restrictions on the way you use your property, such as limiting the permissible amount of impervious surface or prohibiting the use of certain chemicals. It may offer you financial incentives for reducing storm water run-off from your property, conserving water or building a low-impact home.

Water cleanup plans vary in cost and effectiveness. By participating in the TMDL public process and educating yourself about this important issue, you can ensure that your voice is heard.

If you wish to provide your input on the Lake Whatcom TMDL, you will have an opportunity to do so in the near future as it is anticipated that the official TMDL report will be issued for public comment as soon as August.

If you would like to receive notice of when the public review process begins, you should contact Steve Hood, an author of the TMDL report, at shoo461@ECY.WA.GOV. The city and county will also provide notice for public comment after the official TMDL report is released.


Back to Top of Story