Shoreline Management Program

Descriptions

Shoreline Functions
Marine Shorelines
Streams
Lakes
Floodways & Contiguous Floodplains
Associated Wetlands & Deltas

Whatcom County's shorelines are among the most valuable of this state’s natural resources. Shoreline ecosystems are diverse, dynamic, fragile and sensitive environments. Protection and management of these areas is important to the preservation of ecological functions and values of our natural environment, as well as the protection of the public health, safety and welfare of our community. Unregulated or inappropriate development on or near shorelines can result in impacts that threaten the public welfare and shoreline resources, including: pollution, erosion and sedimentation, habitat loss, flooding, or loss of property.

Shoreline Functions

Shoreline functions provide a wide variety of physical and biological functions and perform processes related to fish and wildlife habitat, biological diversity, recreation, flood control, economic resources, aesthetic enjoyment, and so on. Each function is a product of the environmental structure and processes at work within the overall landscape.

What are Marine Shorelines?

Marine shorelines are dynamic and highly energetic coastal environments. The Whatcom County marine shoreline is comprised of multiple components, including: feeder bluffs, beaches, driftways, rock shores, tidelands, spits and other types of coastal shore forms. The formation of marine shoreline features and their continued contribution to, or renewal of, the marine shore environment are dependent on influences from wave, tidal, streamflow, landslide, erosion and longshore transport processes. The varied sectors of the coastal environment resulting from these processes provide a diverse array of habitat and recreational opportunities.

How do Eroding Bluffs contribute to the Marine Shoreline environment?

Eroding shoreline bluffs, or feeder bluffs, are a recurring dynamic geologic process that can be found along Whatcom County’s marine shorelines. Bluffs provide materials necessary for forming and maintaining our beaches, as well as supporting the geologic, biologic, and aesthetic diversity of our shorelines.

Many bluffs are naturally unstable due to soil, slope, and water conditions and are subject to periodic erosion, sliding and slumping. The natural rate of bluff erosion on Whatcom County shorelines varies and depends on several factors, including: exposure to wave action (toe erosion and undercutting), geologic resistance to erosion, and the width and elevation of the beach below.

Sand, gravel and other materials that come from the erosion of these bluffs nourish nearby beaches, spits, and other types of accretion shoreforms. Protection of the natural function of these sources of beach material is vital for the long-term stability of shoreline habitat and process.

Management concerns: Risk of more frequent or more intense bluff erosion and slides can be aggravated by increased development and human activities. Activities that can have potential impacts include: increased or focused drainage concentrations such as stormwater runoff or septic drain fields, removal of trees and vegetation, road cuts, excavation, placement of fill materials on a slope face, and so on.

Periodic efforts to control erosion and stabilize shoreline bluffs to protect developing shoreline areas are complicated by the fact that most of the marine beaches in Whatcom County consist of materials contributed by erosion of feeder bluffs. Not only can these efforts have significant financial impacts, but they can also lead to significant environmental impacts. Prevention of erosion and landsliding in some areas may actually result in considerable declines in sediment supplies that continually replenish our beaches. A reduction in materials can essentially starve beaches and downshore areas, leading to the loss of beaches, fish and wildlife habitat, and accelerate erosion of previously stable areas.

What role do beaches play in the marine shoreline environment?

Beaches are an important part of the shoreline ecology in that they provide a diverse habitat environment for a broad array of marine and terrestrial wildlife in various life stages. They provide valuable habitat functions such as intertidal spawning areas, sheltered tide pools, foraging areas, and nearshore migration corridors.

Beaches also provide multiple opportunities for public recreation, education, scientific study, and scenic enjoyment.

Typical beaches consist of exposed deposits of loose sediments such as sand, silt, gravel and cobbles that have been eroded directly from bluff or bank erosion, fed by nearby river mouths, or transported littorally from other beaches or shoreforms. They can range from several miles in length to small, isolated pocket beaches that can be found between rock headlands.

Beaches are constantly changing due to erosion and accretion (accumulation) processes. Their shape can change from day to day, or even hour to hour. The primary mechanisms that fuel shore changes include:

• wave action
• tides
• littoral drift (transport)
• storms

Management concerns: Development pressures along shorelines can increase desires to stop upland impacts from tidal processes, and to minimize fluctuations of beach features. Often, artificial structures such as bulkheads, groins, and other types of shore defense works are proposed to reduce or prevent potential impacts from these processes. However, use of shore defense works must be evaluated carefully as they can often increase erosion of a beach when waves reflect off a hard structure. Beach erosion resulting from bulkheads and other hard shoreline structures can erode nearby beaches or banks and can destroy or degrade fish and wild life habitat. Alternative management strategies can include maintenance of shoreline vegetation, moving or replacing threatened structures and soft shoreline stabilization.

What Role do Streams Play in the Shoreline Environment?

Streams perform a variety of beneficial functions, including:

• Fish and wildlife habitat
• Flood and storm water control
• Groundwater recharge
• Fish and wildlife migration corridors
• Recreation, education, scientific study, and aesthetic values

Streams are powerful erosional and depositional forces that can continually change and influence the shape of a landscape. Streamflow has a significant capacity to effectively erode and transport rocks, sediments, debris, and nutrients toward river valleys or out to marine shorelines. Erosion varies considerably depending on the volume, speed, and turbulence of streamflow, as well as the stream gradient erosion resistance of the underlying bed rock or sediments.

Variation in stream composition and form, as well as adjacent and overhanging riparian vegetation, are crucial for healthy fish and wildlife habitat. Pools and side channels provide sheltered areas for aquatic wildlife (spawning, hiding, migratory resting areas, etc.). Overhanging trees and riparian vegetation provide habitat and protection for terrestrial wildlife and water temperature control for aquatic life. Well vegetated riparian areas can also provide bank stabilization properties, pollutant filtration, and a source large woody debris.

Management concerns: Development can degrade a stream’s wildlife habitat and water quality, undermining its values and functions by:

• Increasing stormwater runoff and flooding frequency
• Contributing increased levels of sediment, nutrients and pollutants
• Increasing stream turbidity which can reduce the light and oxygen necessary for plant and animal life
• Increasing the volume and velocity of stream flows which can scour stream beds and decrease stream habitat function and diversity
• Removing vegetation along stream banks
• Warming stream temperatures
• Disconnecting the stream from its floodplain and associated wetlands

Why are Whatcom County’s Lakes important?

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.

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. They can provide multiple benefits, including:

• shade and water temperature stability
• shoreline bank stabilization
• a 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.

What are Floodways and Contiguous Floodplain Areas?

Associated floodways and contiguous floodplain areas are those shoreland areas located along a stream system or coastal shoreline that are subject to inundation during flood events. A floodway is the area of a river valley where floodwaters are regularly carried during periods of flooding. It includes all active and inactive stream channels, as well as lands along a stream that are necessary to contain more rapidly moving currents and most of the water volume of a flood event.

Floodplains include all lands along a river or stream that may be subject to periodic inundation by overflow from the base flood of that river or stream.

What are Associated Wetlands and Deltas?

Associated wetlands and river deltas are features that have

developed in association with other shoreline features, such as streams, lakes, or marine shorelines.

Deltas, like the Nooksack River delta, are landforms that are created at the mouth of a river or stream where it enters a larger, slower moving body of water. As water from rivers or streams enter a marine waterbody, the velocity of streamflow decreases and the stream loses capacity to carry most of the sediments and debris that were being transported in the stream load. These sediments then settle out and create a delta deposit at the mouth of the river or stream.

Associated wetlands are generally created and maintained by the controlling factors characteristic of the associated shoreline feature. Backshore, or tidal wetlands, are located along marine shorelines or rivers flowing into marine waters. These are primarily influenced and maintained by tidal action. Riverine wetlands are located in association with river and stream systems and are generally products of flood processes. Wetlands associated with lakes are generally located along the shallow, outer fringe and are controlled by the wind, currents, or seasonal water fluctuations that affect the associated lake body.