Category 4e Assessments and Documentation

A waterbody can be placed in assessment category 4e (Ongoing Restoration Activities) if it’s impaired, but recently completed or ongoing restoration activities are underway to restore the designated use(s) of the waterbody. For Pollutant Reduction Plans (4e plans), the waterbody remains on the federal 303(d) list of impaired waterbodies, but the waterbody is removed from the Verified List, or the addition to the Verified List is postponed for two biennial assessment cycles, to allow for implementation of the activities outlined in the Pollutant Reduction Plan. If at any time the department determines that reasonable progress is not being met, the Verified List will be amended accordingly. This indicates that for waterbodies that have an accepted Pollutant Reduction Plan, the decision to develop a TMDL is deferred until additional information is submitted to complete the pollutant reduction plan, or until additional water quality data are collected documenting that a waterbody is no longer impaired and consideration for Category 2e (Not Impaired - Ongoing Restoration Activities) is warranted.
 
The goal of a Pollutant Reduction Plan is to implement appropriate restoration activities and, if necessary, conduct additional study's so that in future biennial assessment cycles either a Reasonable Assurance Plan (RAP) can be approved, or the waterbody attains water quality standards for the parameter causing the impairment. If the waterbody remains impaired in future biennial assessment cycles and a RAP has not been approved, then the waterbody would likely be placed in Category 5 and included on the Verified List, unless there are additional and substantial restoration efforts scheduled that justify keeping the waterbody in Category 4e for another biennial assessment cycle.
 
There are a number of benefits to implementing such a plan. First, plan development is locally controlled. Second, an accepted plan postpones the development of a TMDL for the impairment by moving straight to restoration activities. Finally, a Pollutant Reduction Plan enables stakeholders to focus on implementing projects and addressing impairments, not on the TMDL process itself. A table containing a statewide comprehensive list of accepted Pollutant Reduction Plans can be found here. 
 

 

Pollutant Reduction Plan Steps (Assessment Category 4e)

Pollutant Reduction Plan Process Step

Description

Plan Initiated

  • Entities have contacted the department expressing interest to pursue a 4e plan
  • Entities have identified recently completed or ongoing restoration activities are underway to restore impaired waterbody
  • Participating partnering entities (public/private) have been identified 

Develop Restoration Plan

  • Waterbody/watershed has been identified
  • Current (impaired) conditions have been described
  • Area of effort has been identified
  • Responsible participating entities have been identified
  • Goal of the plan has been stated
  • Interim water quality–based targets have been determined for the waterbody
  • An estimated target date for water quality criteria to be attained has been determined
  • Point and non-point source pollutants have been identified
  • Projects have been identified to provide the reasonable assurance that the proposed management actions can achieve the designated uses of the waterbody
  • Commitment to take additional actions if the planned activities do not completely redress the impairment have been provided
  • Assurance of confirmed sources of funding has been provided
  • Procedures for monitoring, compliance assessment and reporting have been identified
  • Key indicators that will be assessed to provide assurance of progress in the right direction are included
  • An implementation timeframe for the plan has been established

Finalize Restoration Plan

  • Plan has been presented to the department
  • Supporting documentation has been provided to the department

Finalize Assessment

  • Plan has been approved by the department  

Implement Restoration Plan

  • Projects (structural and non-structural) are moving forward and being implemented
  • Monitoring is continuing

Evaluate Progress

  • Reports are submitted, including updates on planned projects, monitoring results, changes to restoration project schedule, etc.
  • Information has been submitted to complete the pollution reduction plan
  • Water quality monitoring data have been collected to document that the waterbody is no longer impaired

Progress Demonstrated

  • Project implementation is verified
  • Project implementation has resulted in load reductions
  • Improvements in water quality are observed
Last Modified: Thursday, Dec 11, 2025 - 09:52am