Wisconsin’s Consolidated Assessment and Listing Methodology (WisCALM)
Every two years, Sections 303(d) and 305(b) of the Clean Water Act require states to publish a list of all waters not meeting water quality standards and an overall report on surface water quality status of all waters in the state. To assess surface water quality throughout the state Wisconsin's Consolidated Assessment and Listing Methodology (WisCALM) guidance document is updated every two years. WisCALM provides guidance on the assessment of water quality data against surface water quality standards and for Clean Water Act reporting on surface water quality status. WisCALM updates are given to the public for their review before the guidance is finalized. Once finalized, the guidance is used in the current assessment cycle.
Current WisCALM - 2024
The Wisconsin Department of Natural Resources has finalized its updates to WisCALM guidance for the 2024 cycle. This year’s updates included:
- distinction between biological thresholds and water quality criteria;
- new biological metrics (macrophytes, algae);
- new phosphorus biological response indicators (macrophytes, algae, diatoms);
- new oxythermal standards for Two-Story Fishery Lakes;
- new water quality criteria for PFOS and PFOA.
A public comment period was held from Jan. 12 to Feb. 24, 2023. A response to comments is available here: WDNR Response to Public Comment on Draft 2024 WisCALM. The compiled comments are available here: 2024 Public Comments on Draft 2024 WisCALM. Updates made to WisCALM due to public comments are documented in the final 2024 WisCALM Change Log.