Identifiying Impaired Waters

The Clean Water Act calls on each state to list its polluted water bodies and to set priorities for their clean up.

Water bodies qualify for these "impaired waters lists" when they are too polluted or otherwise degraded to support their designated and existing uses.

The impaired waters list is also called the 303(d) list, named after the section in the Act that requires it. The states submit their lists to Congress every two years.

States must develop a watershed restoration action plan called a "Total Maximum Daily Load" (TMDL) for each impaired water body. Many experts believe these plans, also prescribed in Section 303(d), provide the best hope for the clean-up and restoration of our most troubled waters.

What is an "impaired water?"

Any water body that does not meet or is not expected to meet the state's water quality standards after full implementation of existing permits should be considered impaired and placed on the 303(d) list. This includes waters that fail to meet any of their applicable criteria -- whether narrative or numeric, or chemical, physical, or biological. For example, a water that appears to meet all its numeric chemical criteria(such as the criteria for dissolved oxygen, pH, and various common pollutants) but doesn't meet its narrative biological criteria should be listed as impaired.

Neither the cause of a water quality problem nor its solutions need to be clear for a water to be listed. For example, waters in which one or more species are in rapid decline should be listed, even if the specific reasons for their decline may not have been determined yet. In fact, one of the greatest values of 303(d) listings is to trigger analysis to pinpoint sources of problems. Once identified, problems can be addressed through the development of comprehensive watershed restoration plans.

How does the state compile this list?

Each state must report every two years on the health of all its waters, not just those that are impaired. Information from this report, known as the 305(b) report or "biennial water quality report to Congress," is used to develop the "impaired waters" list. Most states start with the data and findings from the 305(b) report and add information from other sources, such as the EPA report of waters affected by nonpoint sources. These tasks are not always performed completely or correctly. States have often failed to list waters for which there was ample evidence of impairment. Most state water quality agencies are able to sample or monitor only a small percentage of their waters consistently enough to detect many water quality problems. Nevertheless, some state agencies have chosen to disregard almost all data other than their own. This is despite the fact that regulations say states must use "all readily available data and information" in developing their 303(d) lists.

Over the years, the EPA has sometimes approved state lists that activists felt were inadequate.In the 1990s, numerous public interest groups across the country filed and won lawsuits against the EPA for approving state lists that were demonstrably incomplete. Consequently, the EPA and the public are now taking a harder look at the adequacy of these lists when they are updated every two years.

How do I find out which rivers are on the list?

Your state water quality agency, your regional EPA office, and EPA headquarters all should have copies of your state's most recent 303(d) list. To find yours on the Web, go to EPA's 303(d) web site.

If my river is not on the list, can I assume it is healthy?

Unfortunately, no. It is possible that it simply wasn't monitored enough to detect problems, or the state's standards for it were too low to trigger a listing. You need to play an active role in ensuring that "impaired waters" lists are complete. Make sure that:

• standards are strong;
• the chemical, physical, and biological health of your waters are regularly monitored; and
• all reliable water quality data are considered by the state whenever the impaired waters list is updated.

Since a listing can lead to restrictions on new discharges, changes to existing permits, and improved management practices to reduce non-point source pollution, the effort to make sure that impaired waters lists are complete is worthwhile.

What happens to the waters on the list?

Once a water body is placed on the "impaired waters" list, it becomes one of many in line for the TMDL (Total Maximum Daily Load) process, as required by the Clean Water Act. This process specifies problems, identifies pollution sources, determines pollution reductions needed to solve the problems, and assigns responsibilities for needed actions. Once impaired waters are placed on the list, proposals for new and increased discharges should receive greater scrutiny. Clean Water Act regulations prohibit new discharges that "will cause or contribute to the violation of water quality standards." In practice, however, many states have continued to allow new discharges to impaired waters. This is one of the issues currently being examined by the EPA as it develops new federal policies and regulations.

Public involvement required in the 303(d)/TMDL process

"Each state shall assemble and evaluate all existing and readily available water quality-related data and information to develop the list…about the following categories of waters: "…Waters for which water quality problems have been reported by local, state or federal agencies; members of the public; or academic institutions. These organizations and groups should be actively solicited for research they may be conducting or reporting." (40 CFR 130.7(b)(5)(iii)) "Calculations to establish TMDLs shall be subject to public review as defined in the State Continuing Planning Process." (40 CFR, 130.7(c)(1)(ii))

What is a "threatened" water?

"At a minimum, 'all existing and readily available water quality-related information' includes but is not limited to… the following categories of waters: (i) Waters identified by the State in its most recent section 305(b) report as 'partially meeting' or 'not meeting' designated uses or as 'threatened;' …(iv) Waters identified by the State as impaired or threatened in a nonpoint assessment submitted to EPA under section 319 of the CWA or in any updates of the assessment." (CWA, section 303(d))

When should a water body be removed from the "impaired waters" list?

Many states are looking for ways to shorten their 303(d) list and thus reduce their responsibilities for developing TMDLs. EPA policy allows states to remove water bodies from the list after they have developed a TMDL or after other changes have been made, such as revisions to one or more permits, that will correct any water quality problems. Unfortunately, this means that attention is drawn away from many water bodies well before necessary changes are made to improve water quality. A TMDL advisory committee recommended that waters stay on the list until they meet water quality standards.

Parties whose activities contribute to a water body's impairment may attempt to persuade the state to remove the water from the list. Sometimes they challenge an agency's claim that narrative standards have been violated. Other times they contend that standards violations are the result of problems that are too difficult to solve, such as the adverse impacts of dams or intensive development in the watershed.

In other words, they may argue that impaired waters should not be listed because the solutions to the problems are too difficult. However, no water body should be removed from the 303(d) list unless either: 1) its problems are solved and standards are achieved, or 2) the designated uses not being achieved are removed. As explained in the previous chapter, designated uses may not be removed unless a formal analysis clearly shows that that they cannot be attained.

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