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Surface Water Quality Standards



The National Clean Water Act of 1972 set in place a program that is intended to restore the chemical, physical, and biological integrity of the nation’s waters. To reach these goals, a series of steps were mandated by Congress for the Environmental Protection Agency and the individual States to take. The first step was for the States to set their own standards for their waters.

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Watershed Assessment and Management
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Triennial Review

In accordance with the Clean Water Act and EPA’s implementing regulations and guidance, the Department of Natural Resources and Environmental Control has begun a triennial review of Delaware’s Surface Water Quality Standards.

The review process opens the standards for review and update based on stakeholder input. For example, past stakeholder input has led to increased protections in some watersheds and changes in protective criteria in others. These changes were based on reasoned proposals with facts and evidence and subject to stakeholder comment and EPA review.

If stakeholders have issues they would like to see addressed in the standards, this is the time to bring them forward.

The Review Process

The process starts with a regulatory Start Action Notice, a proposed “strawman” draft of the regulation, and a stakeholder’s guide to that draft.

The “strawman” draft is based on modifications to the current regulation. Text that would be removed is shown with strikethough. Proposed new language is underlined.

Related Documents

Questions and Comments

Interested stakeholders should contact DNREC’s Water Quality Standards Coordinator David Wolanski for questions or comments on this triennial review before Oct. 1, 2021.

Delaware’s Standards

As established under the Clean Water Act (CWA), water quality standards are the regulations which list designated uses, water quality criteria, and an antidegradation policy. The standards have been established to protect public health and welfare and enhance water quality in the State. While the standards are Delaware regulations, they must be approved by the EPA. If the EPA cannot approve the standards, then EPA is mandated to take over the process and set standards for state waters in a process known as promulgation. Failure by the state or EPA to implement the requirements of the CWA subjects the EPA to citizen law suits to enforce the provisions of the Act.

Designated uses are the water uses specified in water quality standards for each water body. The CWA requires that the uses are to be achieved and protected, even if they are not currently being attained. A water body can have more than one designated use.

Designated Uses in Delaware

Public Water Supply

Secondary Contact Recreation (Wading)

Agricultural Water Supply

Industrial Water Supply

Fish Aquatic Life and Wildlife

ERES Waters (Waters of Exceptional Recreational of Ecological Significance)

Primary Contact Recreation (Swimming)

Cold Water Fish

Harvestable Shellfish Waters

Water quality criteria are designed to ensure the achievement of the designated uses assigned to each water body or segment. The criteria are expressed as concentrations, parameter levels or as narrative statements. It is assumed that if criteria are met, designated uses will be protected.

To receive EPA approval, each state’s water quality standards must include an antidegradation statement and policy. The policy is intended to maintain existing uses and the level of water quality necessary to protect those uses. Under certain circumstances high quality waters may have their quality lowered, but their uses must still be protected and the public must be informed and involved in the decision to allow the quality to be lowered.

The final CWA requirement for state water quality standards is that a public review of them occurs every three years. This process is referred to as the Triennial Review and Delaware has promulgated new Standards based on that review.

DNREC monitors water quality in order to determine compliance with its standards. An annual monitoring plan is developed and implemented.

States are also required to document their progress every two years in a Combined Watershed Assessment Report (305(b) Report) and List of Impaired Waters (303(d) List). This document is submitted to the EPA every two years. EPA then rolls up all the States reports into a national report to Congress.

For waters that fail to meet their standards, Total Maximum Daily Loads (TMDLs) must be developed and watershed plans or strategies are developed to guide implementation actions.




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