Protecting Public Health and the Environment.
Every two years, DEQ is required by the federal Clean Water Act (CWA) to conduct a comprehensive analysis of Idaho's water bodies to determine whether they meet state water quality standards and support beneficial uses or if additional pollution controls are needed. This analysis is summarized in an "Integrated Water Quality Monitoring and Assessment Report" (Integrated Report).
The Integrated Report is submitted to the U.S. Environmental Protection Agency (EPA) for approval and made available to the public. The report serves as a guide for developing and implementing water quality improvement plans (TMDLs) to protect water quality and achieve federal and state water quality standards. An Integrated Report must be approved by the EPA before it can be used by a state to guide its management decisions.
Idaho's most recent approved version is its 2010 Integrated Report. This document will guide DEQ’s water quality management decisions until the 2012 Integrated Report has been approved by EPA.
New: The draft 2012 Integrated Report is open for public comment through 5 p.m., Wednesday, July 10, 2013.
The Integrated Report serves the following three functions:
The main body of the Integrated Report is a discussion of the principles and policies used to compile the report and the assessment methods used to evaluate water quality data. Appendices include schedules for TMDL development that reflect the priority ranking of waters needing a TMDL, maps showing the status of all Idaho waters, DEQ’s response to public comments, and any other relevant supporting information for the Integrated Report. The appendices also contain the lists showing the classification of all state waters into at least one of five different categories. Following the category lists is a list of assessment unit-cause combinations approved by EPA to be delisted.
Category 1 waters are wholly within a designated wilderness or inventoried roadless area where water quality standards are presumed to be attained for all beneficial uses. The only distinction between Category 1 and Category 2 waters is the wilderness and roadless status of the waters in Category 1.
Category 2 waters fully support those beneficial uses that have been assessed. For those water bodies, no existing or readily available data or information indicated a need for a change in the beneficial uses support status.
Category 3 waters have insufficient data or information to indicate an impairment of beneficial uses and to determine if standards have been attained. Category 3 is meant to be temporary until sufficient data and information are obtained to support a designated use attainment determination. However, in Idaho a water may remain in Category 3 under any of the following circumstances: 1) the stream has no flow when visited by DEQ (i.e., is intermittent); 2) access to the monitoring site was denied; or 3) the monitoring site is inaccessible. When DEQ encounters any of these circumstances, every attempt will be made in subsequent years to collect sufficient data and information to support a designated use attainment determination for these waters.
Category 4 water bodies are grouped into one of three subcategories:
Impaired water bodies that do not meet applicable water quality standards for one or more beneficial uses by one or more pollutants are placed in Category 5. Category 5 is a streamlined §303(d) list that excludes waters that have an EPA-approved TMDL (Category 4a) and waters impaired by pollution (Category 4c), such as flow alteration or habitat modification. Waters can only be removed from Category 5 by having either an EPA-approved TMDL or EPA approval to remove based on good cause.
In some cases, a water body may be classified in more than one category. If the water is impaired or if water quality standards are not being met, an assessment unit may show up in both Category 4 and 5. Most occurrences of such multiple listings are for water bodies that are impaired for multiple pollutants or pollution (e.g., flow or habitat alteration). For example, if a water body is impaired by a pollutant (e.g., temperature) and pollution (e.g., flow alteration), then the water body would be listed in Category 5 for temperature and Category 4c for flow alteration.
The 2010 Integrated Report was completed and submitted for EPA approval in August 2011. The report was approved by EPA in September 2011.
The 2010 Integrated Report presents the principles and policies used by DEQ to compile the report, the categorized lists showing the current status of all state waters, and all supporting information, including maps showing the status of all Idaho waters.
Based on existing and readily available water quality data and information assessed for the 2010 Integrated Report, 29% of streams and 4% of lakes are fully supporting state water quality standards, 36% of streams and 56% of lakes are not fully supporting state water quality standards, and 35% of streams and 40% of lakes have not been assessed.
Federal Reporting CoordinatorNicole DeinarowiczDEQ State OfficeWater Quality Division1410 N. HiltonBoise, ID 83706(208) email@example.com
Water Quality StandardsMonitoring and AssessmentTotal Maximum Daily Loads (TMDLs): Water Quality Improvement Plans