Sediment
In This Section
What Are Sediments?
Sediments are any type of loose particles of clay, silt, sand, soil, or other solid substance. Sedimentation is the process by which sediments are transported from one location and deposited to another.
How Can You Measure Sediments?
Both total suspended solids (TSS) and turbidity are measurements that indicate the presence of particles in the water column. The difference between these two measurements is that TSS measures the weight of the material per volume of water while turbidity measures the amount of light scattered from a water sample. This is an important difference when the desire is to quantify the amount of material within a lake or that is being transported from the surrounding watershed into the lake.
Where Do Sediments Come From?
Sediments come from exposed earth and many times sites where erosion is occurring, such as shorelines, stream banks, cleared forests, as well as construction and excavation sites with exposed soils. Water is the main transporter of sediments into water bodies. Waves may erode shorelines, and storm events may wash sediments into surrounding streams, storm drains, or directly into the lake.
Why Is Sedimentation A Problem?
When sediments are washed into streams and lakes, it often takes time for them to settle to the bottom. Whether suspended or settled, sediments can degrade water quality and harm plant and animal life in a few different ways.
- Sediments can carry nutrients , such as phosphorus , bacteria , and other pollutants into waterbodies degrading water quality.
- Suspended sediments can harm plant and animal life by blocking much needed sunlight.
- Sediments can cloud the water to the extent of suffocating plant and animal life.
- Sediments may disrupt aquatic food webs by destroying feeding and spawning grounds for fish and other aquatic animals.
How do you reduce sediment pollution?
- A Lake-Friendly Gardening Kit is available with tips and alternatives to reduce fertilizer and pesticide use, as well as erosion control tips.
- In the Lake Whatcom Watershed, Erosion Control Standards exist for the City of Bellingham and Whatcom County to prevent sediments from entering into Lake Whatcom and our streams at construction sites. The Lake Whatcom Watershed Homebuilding Series provides regulatory guidance to those who are building their own home.
The Native Plants for Landscaping in Bellingham, Washington booklet is available from the City of Bellingham's Planning Division, as well as online.
