Effects of Siltation on Water Bodies
Sediment entering a water body negatively impacts both water quality and quantity in many ways:
• Reduces Water Storage Capacity- Each cubic yard of sediment in a lake displaces 202 gallons of
water. An acre of water with 1 foot of sediment (approximately 1,613 cubic yards) has removed
approximately 326,000 gallons of water storage capacity from the lake. When 3 feet of sedimentation has
occurred in an acre of water, the water body has lost approximately 1 million gallons of storage capacity.
This can severely limit the use of the lake for drinking water storage and irrigation needs.
• Reduces Recreational Use-When sediment is deposited in a water body, boat use is limited by the
newly created shallow water. Many lakes cannot be accessed in the upper reaches because of the
sedimentation. In tidal areas inlets become physically blocked by sediment and shifting sand.
• Stimulates Aquatic Weed & Algae Growth-Because sedimentation is the result of soil erosion in the
watershed, nutrients (nitrogen and phosphorus) are often transported on the soil particles into a lake. The
added nutrient influx coupled with the shallower water creates prime conditions for noxious aquatic growth.
Weed and algae are often the symptoms of sedimentation.
• Degrades Habitat for Fish Populations-Sedimentation can have negative impacts on the fish
populations of a lake by: (1) covering spawning areas, (2) interfering with oxygen uptake by irritating gills,
(3) reducing bottom organisms, a key component to the aquatic food chain, and (4) reducing plankton (the
base of the food chain) by having suspended particles limit light penetration.
• Degrades the Appearance of the Lake-Sedimentation is often visible in the lake by residents who
enjoy the serenity of waterfront living. Muddy water and visible sand bars are the two most common
complaints from lake property owners.
• Reduction of Waterfront Property Values- When sedimentation has occurred to the extent that lake
use and lake appearance are hindered, property values around the lake often drop. If a boat dock cannot
be accessed, then the lake is of little use to the property owner.
Regardless of the use of the lake, siltation in a water body will occur and will not go away with time. The
eventual build-up of sediment will break water level and begin to support more land-based plants and trees.