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Contact EPA Pacific Southwest Water Division

Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Watershed Priorities

Measure W Watersheds

Guidance on Reporting Watershed Improvement

EPA has prepared guidance to help "implement" this measure. The guidance defines the performance measure and key terms (e.g., improvement), and provides reporting format templates.

Please contact us if you have any questions, including if you have a watershed that you would like to track for this measure.

About PDF

Map of EPA Region 9 Arizona California Hawaii Nevada

Measure “W” (also known as the Watershed Improvement Measure (WIM) and SP-12) is a key performance measure in EPA’s Strategic Plan. The measure tracks watersheds where water quality conditions have improved by utilizing a watershed approach. One of the primary purposes of this measure is to model and demonstrate the effectiveness of the watershed approach. EPA has a nation-wide goal to improve water quality conditions in 250 watersheds for 2012. EPA Region 9 and our state water quality agency partners have agreed to track the following watersheds for purposes of reporting on this measure and documenting environmental results, and to better focus our water quality restoration activities by identifying needs, sharing information, providing assistance and learning more about the related challenges. We expect some of these watersheds to show improvement by 2012 for the identified pollutant. Additional watersheds may be added and/or substituted.


North Coast (RB1)

  • Scott River (French and Moffett Creeks)
  • Terwar Creek
  • Garcia River
  • Shasta River

San Francisco Bay (RB2)

    • Napa River
    • Tomales Bay

Central Coast (RB3)

  • San Lorenzo River
  • Morro Bay Watershed (Chorro, Warden and Los Osos Creeks)
  • Oso Flaco Creek

Los Angeles (RB4)

Central Valley (RB5)

Lahanton (RB6)

  • Lake Tahoe

Colorado River (RB7)

  • New River

Santa Ana (RB8)

San Diego (RB9)

  • Chollas Creek
  • San Diego Beaches



  • Hanalei Bay
  • Waimanalo River
  • West Maui – (Honokohua to Launiupoko–Honolua Bay)


  • Las Vegas Wash


Jared Vollmer – Arizona
(415) 972-3447

Susan Keydel – California
(415) 972-3106

Hudson Slay – Hawaii
(808) 541-2717

Stephanie Wilson – Nevada
(775) 885-6190

Tina Yin – Regional Coordinator
(415) 972-3579

Sam Ziegler - Region 9
(415) 972-3399

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