Lakes in Whatcom County are important because they provide critical fresh water environments for many aquatic plants, animals, fish, and insects, as well as provide multiple recreational, sport and enjoyment opportunities. Several of Whatcom County's lakes, including Lake Whatcom and Lake Samish, also provide significant sources of potable water for human consumption.

Lakes are bodies of water that are supplied with sufficient water flow to keep their basins at least partially filled throughout the year. The water balance of most lakes is maintained by inflow of surface water. Though lakes can also be fed by underwater seeps or springs, most lakes are both fed and drained by streams.
Lake with minimal cloud cover
Habitat functions provided by lake spawning, breeding, rearing and foraging areas for fish, amphibians, waterfowl and other wildlife. Shallow, sheltered shoreline areas and riparian vegetation such as trees, shrubs, grasses, and other plants along a lake shore are important for fish and wildlife habitat.

Lakes can provide multiple benefits, including:
  • Shade and water temperature stability
  • Shoreline bank stabilization
  • Source of insects for foraging wildlife
  • Protective cover from overhanging branches and leaves
  • Under water cover from submerged vegetation
  • Protection from wind and wave action
  • Reduction and filtering of stormwater runoff
Management Concerns
Lake ecosystems are affected by a variety of influences outside of the water. Development impacts along lake shorelines vary with the type of development and the type of lake where it occurs. Common development impacts are result in removal of native shoreline vegetation, bulkheads, increased stormwater runoff, introduction of dissolved nutrients, and pollutants.

Removal of shoreline vegetation, aquatic and/or riparian, can result in a loss of fish habitat, shade, insects and other aquatic organisms important to fish foraging. Lake shore defense works, like marine shore defense works, may also result in increased erosion of lake sediments which can disturb or destroy fish spawning and rearing habitat, as well as erode neighboring beaches and uplands. Increased stormwater runoff and toxics can decrease overall water quality, increase sediment inputs and turbidity, and increase nutrient inputs which can contribute to more frequent occurrences of aquatic weed growth and algae blooms like those experienced at Lake Samish in recent years.