Suspended Sediments in South San Francisco Bay By Anna Kunkel Maidment-GIS

Objective To determine how different factors affect the levels of suspended sediments in the South San Francisco Bay. Factors examined –Location –Time of the Year –Precipitation

What are Suspended Sediments? Sediments--solid particles transported in fluid media or found in deposit after transportation by flowing water, wind, glacier and gravitational action. Suspension due to River TurbidityWind Waves

Why do we care? Transport adsorbed toxic substances Block light from reaching submerged vegetation Absorb heat from sunlight Reduces the dissolved oxygen level Changes morphology of an area through sedimentation Mississippi River Sediment Plume

South San Francisco Bay

USGS Testing Sites 36 testing sites in San Francisco Bay –Sites 21 through 36 in south –Located along central deep channel Monitored monthly using submersible instrument package –Discrete measurement of concentration –Optical backscatter sensor

Southern vs. Northern Testing Sites Reasons for Difference in Suspended Sediment Levels Closer to Shoreline Farther From Shoreline River OutletsNo River Outlets Shallower Testing Sites Deeper Testing Sites Corte Madera Cr Stevens Cr Coyote Cr

Precipitation

For February (Winter)For November (Fall) Precipitation Maps

Conclusions The concentration of suspended sediments depends on –Location Sites closer to shore are affected by more river and wind effects –Season Higher levels occur during fall and winter. –Precipitation Higher levels occur with more precipitation. The Yangtze River as it empties into the East China Sea