Flood Control and Erosion Control in Contra Costa County Streams

StormCon WorkshopMay 12, 2006San Ramon, California

Mitch AvalonContra Costa County Flood Control District

I Live in a Watershed

Flood Control District Role/Responsibility/Opportunity

Manage 72 miles of stream channel Manage regional detention basins Watershed-wide planning C-3/HMP regional facilities

The Flood Protection System

Green Valle

y Ck

Ala

mo

Ck

Wes

tSycamore Ck

San Ramon Ck

San

Ram

on C

k

Las Trampas Ck

Upp

er Pine C

k

Galindo Ck`G

rays

on

&

Mu

rder

ers

Cks

Pach

eco

Ck

Rodeo CkPinole CkGarrity

CkRheem CkSan Pablo Ck

Wildcat Ck

East Antioch Ck

Mar

sh C

k

Sand Ck

Deer Ck

Dry Ck

Kello

gg C

k

Marsh Ck Reservoir

Contra Costa County Creek Conditions

Flood Control District Role/Responsibility/Opportunity

Manage 72 miles of stream channel Manage regional detention basins Watershed-wide planning C-3/HMP regional facilities

Changing Strategies

Stormwater connectivity or stormwater retention

Armored channels or natural systems Floodplain function Land use changes and re-engineered

creeks Maintenance activities

1800

Historical Coyote Creek Drainage Network

2005

Modern Coyote Creek Drainage Network

Unconfined Groundwater Recharge Basin

2005

Las Trampas Creek - 1966

Pinole Creek Flood Control Channel

Pinole Creek Greenway Project – Upper Reach

Pinole Creek Greenway Project – Lower Reach

Recent and Planned Restoration Projects

Pacheco Marsh Restoration Marsh Creek Reservoir Expansion Strentzel Creek Meadow Restoration Knightsen Biofilter Canada del Cierbo Restoration San Ramon Creek Bioengineering Repair

Pacheco Marsh – 120 acre Tidal Wetland Restoration

Marsh Creek Reservoir

Marsh Creek Reservoir – 218 Acre Expansion

Strentzel Creek Meadow Grading Plan

Strenzel Creek Planting

Downtown Knightsen

Canada del Cierbo Mitigation

Canada del Cierbo Mitigation

Collaboration – Collaboration - Collaboration

Watershed Councils/Creek Groups Cities/Municipal Advisory Councils Neighborhood groups/property owners Contra Costa Watershed Forum

Watershed Atlas

Stormwater Program Role

Coordinated development of HMP Stormwater C-3 Guidebook Case Studies/Research Education/Adaptive Training Stream and Wetlands System Protection

Policy

Downtown Walnut Creek - 1958

A New Approach

Historic Design Concept- Protect structures and convey stormwater off as fast as possible

New Design Concept- Protect structures and retain stormwater as long as possible

Grayson Creek Channel - 1957

A New Approach

Historic Design Concept- Protect structures and convey stormwater off as fast as possible

New Design Concept- Protect structures and retain stormwater as long as possible

Hydrograph Modification Management

Increase retention time Increase stream stability Healthy sustainable watershed Cumulative improvement

The Impact of Impervious Surfaces

Stream Stability Approach

Historical System Present System Compare Past and Present Understand Changes Recommendations and Restoration

Templates

Sustainable Watershed

Community

Water Quality/Quantity

(Hydrology)

Habitat

(Ecology)

Creek Stability/Function

(Geomorphology)

The Future

At the parcel levelLIDHomeowner educationLandscape contractors

The Future

At the Watershed level 2nd generation facilities System preservation/

replacement Clean Water Regional

Treatment Regional retention facilities The 50 year plan

Marsh Creek Reservoir

G:grpdata/admin/mitch/pp presentation/FC-Erosion Control

Remember you live in a Watershed too………..