What is a TMDL?

A TMDL is a numerical value that represents the highest amount of a pollutant a surface water body can receive and still meet the standards. The federal Clean Water Act requires states to develop a TMDL plan for each water body on the state's polluted waters list, also known as the 303(d) list.

Total Maximum Daily Load

Hayden Lake TMDL Implementation Plan Update Report - 2022

Geoff Harvey, HLWA President Emeritus

A Summary of Hayden Lake Water Quality Monitoring 1976 - 2006

Note: Links to copies of the original water quality studies are at the bottom of this summary 

Introduction:  The purpose of this summary is to give any individual understandings of the types of water quality monitoring that have been conducted on Hayden Lake.  There are six distinct monitoring efforts on the lake's water quality and one on its near shore septic systems ranging over a period from 1972 through 2006.  This summary will attempt to report the approaches taken, the data developed, and, as important, how the approach did not reveal the entire picture. Any opinion stated is that of one professional with many years of water quality experience and might be disputed by another's opinion.   This document is a summary.  The actual reports on which it is based are linked to the report at the appropriate location so those wishing more in depth information may consult the report.