Arkansas’s 303(d) List Overview

What is the Impaired Waterbodies List - 303(d) List?

The Impaired Waterbodies List, commonly called the 303(d) List, is a list of waters not meeting water quality standards and/or designated uses in accordance with the federal Clean Water ACT (CWA) Section 303(d). CWA Section 305(b) requires each state to include the 303(d) list in its report on the condition of waters of the state every two years.

Water quality standards are designed to enhance the quality, value, and beneficial uses of the surface waters of Arkansas. They aid in the prevention, control, and abatement of water pollution; provide for the protection and propagation of fish and wildlife; and ensure that recreation in and on the water is safe. Standards can be numeric or narrative. Arkansas’ Water Quality Standards are Regulation 2 of the Arkansas Pollution Control and Ecology Commission.

Designated uses are appropriate water uses to be achieved and protected for specific waterbodies. Designated uses can include public water supply; the protection and propagation of fish, shellfish, and wildlife; recreational, agricultural, industrial, and navigational purposes; and ecological and aesthetic value. A single waterbody can have many designated uses at the same time: the creek you swim in may also be used to irrigate farm land.

Our water quality standards protect state waterways for the following designated uses:

Extraordinary Resource Waters –
are characterized by scenic beauty, aesthetics, scientific values, broad scope recreation potential, and intangible social values.
Ecologically Sensitive Waterbody –
provides habitat within the existing range of threatened, endangered, or endemic species of aquatic or semi-aquatic life forms.
Natural and Scenic Waterways –
identifies segments which have been legislatively adopted into a state or federal system.
Primary Contact Recreation (swimmable) –
involves full body contact.
Secondary Contact Recreation (wadeable) –
involves secondary activities like boating, fishing, or wading.
Fisheries (fishable) –
provides for the protection and propagation of fish, shellfish and other forms of aquatic life.
Domestic Water Supply –
is protected for use in public and private water supplies.
Industrial Water Supply –
is used for process and cooling water.
Agricultural Water Supply –
is used for irrigation of crops and/or consumption by livestock.

How is the 303(d) list created?

A waterbody is considered impaired and placed on the 303(d) List if it does not meet water quality standards and/or designated uses as described in APC&EC Regulation 2. The Office of Water assesses impairment by applying its' comprehensive Assessment Methodology to water quality data.

Water quality data from stream and lake sampling sites are considered during the development of the 303(d) List. The evaluated water quality data are collected by multiple entities, including: DEQ; other state, federal, and local government agencies; and private entities in Arkansas and from surrounding states whose data meets or exceeds DEQ’s or the United States Geological Survey’s quality assurance/quality control protocols.

303(d) List Categories:

Waterbodies are classified into the following categories:

  • Category 1
    Attains all water quality standards for all designated uses; categorized by existence of a Total Maximum Daily Load (TMDL) or not for one or more constituents:
    • 1a. Attaining all water quality criteria and supporting all designated uses, no use is threatened. No TMDL exists for any constituents.
    • 1b. Attaining all water quality standards for all designated uses; however, a TMDL remains in place for one or more constituents.
  • Category 2
    Available data and/or information indicate that some, but not all of the designated uses are supported.
  • Category 3
    Insufficient data and/or information are available to make a use support determination:
    • 3a. No data available.
    • 3b. Insufficient data available.
      • Data do not meet all quality requirements outlined in this assessment methodology;
      • Waters in which the data are questionable because of Quality Assurance and/or Quality Control (QA/QC) procedures and/or the AU requires confirmation of impairment before a TMDL is scheduled.
      • Where limited available data and/or information indicate potential impacts or downward trends in water quality, the following water bodies in Category 3 may be prioritized (on a case-by-case basis) for additional investigation: waters designated as ERW, ESW, or NSW; domestic water supplies; and waters located in known karst areas.
  • Category 4
    Water quality standards are not attained for one or more designated uses but the development of a TMDL is not required because:
    • 4a. A TMDL has been completed for the listed parameter(s); or
    • 4b. Other management alternatives are expected to result in the attainment of the water quality standard; or
    • 4c. Non-support of the water quality standard is not caused by a pollutant.
  • Category 5
    The waterbody is impaired, or one or more water quality standards may not be attained. Waterbodies in Category 5 will be prioritized as:
    • High
      • Truly impaired; develop a TMDL or other corrective action(s) for the listed parameter(s).
    • Medium
      • Waters currently not attaining standards, but may be de-listed with future revisions to APC&EC Rule No. 2, the state water quality standards; or
      • Waters which are impaired by point source discharges and future permit restrictions are expected to correct the problem(s).
    • Low
      • Waters currently not attaining one or more water quality standards, but all designated uses are determined to be supported; or
      • There is insufficient data to make a scientifically defensible decision concerning designated use attainment; or
      • Waters DEQ assessed as unimpaired, but were assessed as impaired by EPA.

A TMDL is a calculation developed for some waters that are not attaining water quality standards and/or designated uses. A TMDL calculates the maximum amount of a constituent a waterbody can receive and still meet the standards and designated uses. A TMDL accounts for both point source and nonpoint source discharges.