Watershed Publications and Reports

pdf Most documents are pdfs and will require Adobe Acrobat Reader for online viewing.

Ross Valley


On April 3, 2012, the Flood Zone 9 Advisory Board adopted the 10 Year Work Plan that will create a 25-Year-Flood (4% ACF) level of flood protection. This is the first phase of a 20 year program to achieve a 100-Year-Flood level of protection.

Technical Memo - 10 Year Work Plan

Cost Estimates - 10 Year Work Plan (Updated December 16, 2014)

Maps - 10 Year Work Plan


On May 23, 2011, the Capital Improvement Plan Study was presented at a public meeting of the Flood Zone 9 Advisory Board at San Anselmo Town Hall. You can view a video recording of that meeting here. The video is divided into segments by subject matter and you can view one or all of the videos.

Capital Improvement Plan Study for Flood Damage Reduction and Creek Management for Flood Zone 9/Ross Valley by Stetson Engineers, May 2011


These plates and graphs accompany the Capital Improvement Plan Study Report

Creek Capacity Improvement Measures



Sleepy Hollow

San Anselmo
2-1 General Overview.pdf 2-2.1 FF.pdf 2-3.1 SH.pdf 2-4.1 SA.pdf
  2-2.2 FF.pdf 2-3.2 SH.pdf 2-4.2 SA.pdf
  2-2.3 FF.pdf 2-3.3 SH.pdf 2-4.3 SA.pdf
  2-2.4 FF.pdf 2-3.4 SH.pdf 2-4.4 SA.pdf
    2-3.5 SH.pdf 2-4.5 SA.pdf
    2-3.6 SH.pdf 2-4.6 SA.pdf
    2-3.7 SH.pdf 2-4.7 SA.pdf
      2-4.8 SA.pdf


Detention Basins

(Proposed concepts are from 2011; See project webpage or fact sheets for current information)


Phoenix Lake

PL Existing

PL Proposed

Lefty Gomez Field

LG Existing

LG Proposed

LG Architect's Rendering

Loma Alta

LA Existing

LA Proposed

Memorial Park

MP Existing

MP Proposed

Red Hill Field

RH Existing

RH Proposed

Flood Reduction from Proposed Measures

100 Year Flood - Existing Conditions plus Detention Basins

100 Year Flood - Existing Conditions plus Creek Improvements

Flood Frequency Maps

5 Year Flood

10 Year Flood

25 Year Flood

50 Year Flood

100 Year Flood


TECHNICAL MEMORANDA - Capital Improvement Plan Study

Technical Memo #1

Existing Conditions

Technical Memo #2

Detention Basins

Technical Memo #3

Critical Reach Analysis

Technical Memo #4

Earthen Channel Analysis

Technical Memo #5

Economic Analysis