California Water Boards' Annual Performance Report - Fiscal Year  2017-18 

PLAN AND ASSESS: SURFACE WATER QUALITY

MEASUREMENTS  - Data last updated on: 

WHAT THE MEASURE IS SHOWING

The Water Boards have identified 167 impaired watersheds to track progress and document improvements in water quality conditions using a watershed approach related to a key national performance measure in the U.S. Environmental Protection Agency's (USEPA) 2006-2011 Strategic Plan, the Watershed Improvement Measure (also known as SP-12 or "Measure W"). These "watersheds of focus" are of varying sizes, and most include multiple watersheds defined by 12-digit Hydrologic Unit Codes (HUC-12). Additional watersheds may be added and/or substituted.

For FY 2017-18, watershed-wide improvements, and descriptions of the watershed approaches implemented to achieve the water quality improvements, were documented in watershed improvement reports for 15 of California's 167 watersheds of focus.

WHY THIS MEASURE IS IMPORTANT

California has over 700 water bodies that do not meet one or more water quality standards. These impaired water bodies, which are identified on the federal Clean Water Act Section (CWA) 303(d) list for the State, are subject to the development of Total Maximum Daily Loads (TMDLs), and a variety of water quality improvement and restoration activities. Experience has shown that, to solve these problems, TMDLs and watershed plans are needed to analyze and quantify the specific causes and sources of water quality problems, identify measurable water quality goals, and implement specific actions to improve water quality. Furthermore, effective watershed management includes public and private entities collaborating within a watershed to protect our waters and other resources of community concern. The California Water Boards and the USEPA agreed to track and report progress on the "watersheds of focus" to model and demonstrate the effectiveness of the watershed approach to improving water quality. These efforts will enhance water quality improvement activities through better identifying needs, targeting activities, and sharing information

TECHNICAL CONSIDERATIONS

• Data Source: State Water Board's Nonpoint Source Program. Period: July 1, 2017 - June 30, 2018 .
• Unit of Measure: Number of impaired watershed units (defined as 12-digit HUCs) for which documented improvements in water quality in "watersheds of focus" occurred using the watershed approach.
• Data Definitions: Watersheds of Focus: The number of specific watersheds identified by the Water Boards and USEPA for purposes of tracking and documenting progress in improving water quality conditions using the watershed approach. Pollutants Monitored: The number of water quality parameters (e.g., sediment, nutrients, bacteria) being tracked for determining improvements in water quality conditions in watersheds of focus. Watershed Units Improved: Per USEPA guidance, as improvements in water quality are documented in watershed improvement reports, the number of watershed units improved (defined as 12-digit HUCs) are reported.
• References: More information on the "Watershed Improvement Measure" (also known as SP-12, or Measure W). USEPA Guidance on SP-12.

GLOSSARY

Hydrologic Unit Code (HUC)

The hydrologic unit code (HUC) is the "address" of the watershed. The HUC is the numerical code of the USGS watershed classification system used to identify the watersheds, or drainage basins, at various scales. The HUC organizes watersheds by a nested size hierarchy, so large scale watershed boundaries for an entire region may be assigned a two-digit HUC, while small scale, local watershed boundaries (within the larger regional watershed) may be assigned a 12-digit HUC. Although the watershed boundaries for this measure are those established at the "12-digit HUC" scale, which averages 22 square miles in size, the watershed approach can be applied at any appropriate scale, including scales smaller or larger than HUC-12 watersheds. For more information: http://www.epa.gov/watershed/address-x.html

Impaired Water Bodies/Watersheds

Impaired water bodies are those that are not supporting one or more of their beneficial uses designated in water quality standards. For the purpose of this measure, "impaired water bodies" are those identified by the State and USEPA in the 2002 Clean Water Act (CWA) Section 303(d) list (which is used as a baseline for this measure). For the purpose of this measure, an "impaired watershed" is a watershed containing one or more impaired water bodies.

Improved (Water Quality Conditions in Impaired Watershed)

For the purpose of this measure, "improved" means either that: (1) one or more of the impairment causes identified in the CWA Section 2002 303(d) list are removed for at least 40 percent of the impaired water bodies or impaired miles or acres in the watershed; or (2) there is significant watershed-wide improvement, as demonstrated by valid scientific information, in one or more water quality parameters or related indicators associated with the impairments. For more information, see USEPA's Guidance for Reporting Watershed Improvement under Measure SP-12 - FY 2009

Total Maximum Daily Load (TMDL)

A TMDL is a calculation of the maximum amount of a pollutant that a water body can receive and still safely meet water quality standards. TMDLs are required for impaired water bodies on the federal Clean Water Act Section 303(d) list.

Watershed Approach

A watershed approach is a coordinating process for focusing on water resource problems within a watershed that: (1) is focused on hydrologically defined areas, (2) involves key stakeholders, (3) uses an iterative planning or adaptive management process to address priority water resource goals, and (4) uses an integrated set of tools and programs. More information

Watersheds of Focus

Watersheds of varying sizes, most including multiple watersheds defined by 12-digit Hydrologic Unit Codes (HUCs), where improvement may be achieved in the near term (by 2012), or may take longer. Additional watersheds may be added and/or substituted.

Detailed Table of Watershed Improvement Measure

Preliminary Healthy Watershed Assessments