Stream Sediment

What Is Stream Sediment and Why Monitor It?

Sediment occurs naturally in streams but can be considered a pollutant when found in high concentrations in stream ecosystems. Too much fine sediment moving through a stream system causes problems for aquatic life, including direct impacts on the health of young salmonids and the success of eggs and fry. This is the case in our Sonoma Creek Watershed; it is caused by land use change and stream bed erosion. As a result Sonoma Creek has been listed as impaired for sediment pollution under the Clean Water Act. Since this listing and the need for scientific information to support restoration actions, Sonoma Ecology Center has taken a lead role in the analysis of the problem and proposal of solutions as well as conducting ongoing monitoring. The Sonoma Creek Sediment Source Analysis (SEC et al., 2006)< is the definitive scientific study for Sonoma Creek's sediment problem. It guides the actions mandated and recommended by the State Water Resources Control Board as part of the Sonoma Creek Sediment Total Maximum Daily Load (TMDL)<.

Sediment monitoring since completion of the TMDL Sediment Source Analysis is continuing forward with two main emphases:

  • Turbidity grab sampling in locations where turbidity to suspended sediment relationships are known, conducted during sediment "first flush" (the first storm of the rainy season that produces enough flow to lift and transport sediment) and
  • continuous monitoring by our multi-parameter stream probe at Station A in Eldridge.

Data collected are compared with the baseline data presented in the Sediment Source Analysis to evaluate condition and trend of this important indicator of watershed health. Please see the individual sampling stations to find data.

Years Monitored: 
Methods Summary59.26 KB
2014 Turbidity and Suspended Sediment Data185.43 KB
Quality Assurance Project Plan for Turbidity and Suspended Sediment Monitoring2.87 MB
Turbdity_VS_Suspended Sediment 2014380 KB
Maximum Severity Index during First Flush on Sonoma Creek446.86 KB
SSC_Turbidity_Monitoring_Sites.jpg1.01 MB
SSC_Sites.jpg1.01 MB
SSC_Turbidity_Monitoring_Sites_sm.jpg317.66 KB