150 likes | 229 Views
SONOMA CREEK AND SEDIMENT: KNOWING WHAT WE DON’T KNOW. MAY 2011. SONOMA CREEK AND SEDIMENT: KNOWING WHAT WE DON’T KNOW. MAY 2011.
E N D
SONOMA CREEK AND SEDIMENT: KNOWING WHAT WE DON’T KNOW MAY 2011
SONOMA CREEK AND SEDIMENT: KNOWING WHAT WE DON’T KNOW MAY 2011 “. . . somebody's certainly going to . . . find out what he knows that they may not know, and make sure he knows what they know that he may not know.“ --Donald Rumsfeld
Sonoma Valley • 166 square miles • 0 to 2,739 feet msl • land uses: • 30% forest20% grassland & rangeland30% agricultural 15% developed5% wetland • beneficial uses:COLD, WARM, REC-1, REC-2, MIGR, RARE, SPWN, WILD
Sonoma Creek Watershed • 23 to 50 inches annual rainfall • 465 miles of USGS blue-line stream • Chinook salmon, steelhead trout, California freshwater shrimp • Hydromodified:95% freshwater marsh drained20% alluvial channels once disconnected now connected
State Listing SECTION 303(d): SEDIMENT (NUTRIENTS & PATHOGENS) Funding FUND STUDY TO ASSESS POLLUTANT (SEDIMENT) Study 1: Limiting Factors Analysis WHAT FACTORS LIMIT STREAM HEALTH? Study 2: Sediment Source Analysis WHAT ARE THE MAIN SEDIMENT SOURCES? Measures for Action HOW AND WHERE DO WE FOCUS IMPLEMENTATION? Sonoma Creek Sediment TMDL Main focus: steelhead trout
Life Stages and Limiting FactorsWhat factors limit stream health in Sonoma Creek and tribs?
Sediment-Related Limiting Factors: highest during spawning and juvenile rearing
Sediment Source AnalysisWhat are the major sediment sources and how much do they input? + = human natural
Stream channel contribution • 67,700 tons/year • 64% human caused
How? (Required) • Control upslope sediment discharges--road and stream crossings--surface erosion--shallow landslides and gullies • Reduce sediment discharge from channel incision--attentuate, reduce storm peaks--avoid impacts to stream corridors
How? (Recommended) • Support habitat enhancement actions--increase channel complexity--enhance summer base flows--address fish barriers • Reduce sediment discharge from channel incision--reverse adverse impacts of incision--implement stream restoration projects
State Listing SECTION 303(d): SEDIMENT (NUTRIENTS & PATHOGENS) Funding FUND STUDY TO ASSESS POLLUTANT (SEDIMENT) Limiting Factors Analysis WHAT FACTORS LIMIT STREAM HEALTH? Source Analysis WHAT ARE THE MAIN SEDIMENT SOURCES? Measures for Action HOW AND WHERE DO WE FOCUS IMPLEMENTATION? (leads to Study 3) Sonoma Creek Sediment TMDL Main focus: steelhead trout
Where? • Pilot study for site prioritization • San Francisco Foundation Bay Fund – 2008 to 2010 • Where are the ten highest-producing sites affecting best-value spawning and rearing habitat? • Upper watershed, 60 square miles above Eldridge
What are the highest producing sites throughout the watershed?