590 likes | 877 Views
Western Washington has lots of wetlands due to lots of rain!. Wetlands cover about 938,000 acres in Washington State, or about 2 percent of the state's total land. Wetlands are critical to the overall health of our watersheds.
E N D
Western Washington has lots of wetlands due to lots of rain!
Wetlands cover about 938,000 acres in Washington State, or about 2 percent of the state's total land. Wetlands are critical to the overall health of our watersheds.
70% of the tidal - emergent wetlands in the Puget Sound have been lost due to diking, dredging and filling activities.
By 1980, Urbanized wetlands in the Puget Sound have suffered losses ranging from 90 to 98%. U.S. Geological Survey of 11 Puget Sound estuaries estimates 100% of Puyallup River wetlands, 99% of Duwamish River wetlands and 96% of Samish River wetlands are lost and more degraded.
Biological Productivity Wetlands are the among the most productive ecosystems in the world. Immense varieties of species of microbes, plants, insects,amphibians, reptiles, birds, fish, and other wildlife depend in some way on wetlands. Wetland plants play an integral role in the ecology of the watershed.
Wetland functions include many that are important to people, including: Flood control Ground water recharge Water filtration and purification Erosion control Wildlife habitat Recreation Research and education Regional economic vitality
SystemWetland description A. Palustrine..... freshwater wetlands in which vegetation is 1. predominantly trees (forested wetlands); 2. shrubs (scrub- shrub wetlands); 3. emergent, erect, rooted herbaceous plants; or submersed and (or) floating plants (aquatic beds). 4. intermittently to permanently flooded open-water bodies of less than 20 acres in which water is less than 6.6 feet deep.
Shrub-scrub Wetland in the Nisqually National Wildlife Refuge
Horsetail Common Wetland Plant
B. Lacustrine.... freshwater wetlands within an intermittently to permanently flooded lake or larger than 20 acres and (or) deeper than 6.6 feet. C. Riverine....... freshwater wetlands within a channel. D. Estuarine......Tidal wetlands and the mixing of sea- water and freshwater. E. Marine.........Tidal wetlands exposed to waves + water having a salinity greater than 30 ppt.
The federal regulations Section 404 of the Clean Water Act define wetlands as: Those areas that are inundated or saturated by surface or ground water (hydrology) at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation (hydrophytes) typically adapted for life in saturated soil conditions (hydric soils). Wetlands generally include swamps, marshes, bogs, and similar areas (40 CFR 232.2(r)).
WA Fish+Wildlife Service states 85% of WA wildlife are“Critically Dependent” on wetlands for a portion of their lifecycle. Although wetlands are about 3.5 percent of U.S. land area, >1/3 of the US threatened and endangered species live only in wetlands.
Spotted Frog The eggs are deposited in spherical clusters of up to 1,300 eggs which float freely.
Predators of Columbia Spotted Frog adults include river otters, raccoons, herons and garter snakes, and the invasive Bullfrogs.
Cattails and Sitka spruce, salamanders and great blue herons, white-tailed deer and juvenile salmon - wetlands are overflowing with life. In all, some 212 species of wildlife and many species of plant life depend on western Washington's wetlands for survival. Wetland plants provide breeding and nursery sites, resting areas for migratory species, and refuge from predators. Decomposed plant matter (detritus) released into the water is important food for many invertebrates and fish both in the wetland and in associated aquatic systems.
Wetland functions include many that are important to people, including: Flood control Ground water recharge Water filtration and purification Erosion control Wildlife habitat Recreation Research and education Regional economic vitality
Wetlands store precipitation and surface water and then slowly release the water into associated surface water resources, ground water, and the atmosphere.
Wetlands help protect properties from potential flood damage. The value of flood control increases with wetland area and location. Wetlands within and upstream of urban areas are particularly valuable for flood protection. The impervious surface in urban areas greatly increases the rate and volume of runoff, thereby increasing the risk of flood damage.
Ground water recharge Wetlands recharges the water table directly and the force or “hydraulic head” for ground water discharge. The extent of ground water recharge by a wetland is dependent upon soil, vegetation, site size, and total volume.
WATER FILTRATION A wetland with more vegetation will intercept more runoff and be more capable of reducing runoff velocity and removing pollutants from the water than a wetland with less vegetation
Scientists have estimated that wetlands may remove between 70% and 90% of entering nitrogen. Riparian forests can reduce nitrogen concentrations in runoff and floodwater by up to 90% and phosphate concentrations by 50%
Removal of Pathogens Fecal coliform bacteria and protozoans, threats to human health, enter wetlands through municipal sewage, urban stormwater, leaking septic tanks, and agricultural runoff. Bacteria attach to suspended solids that are then trapped by wetland vegetation .
Certain wetlands play an important role in removing metals from other water resources, runoff, and ground water. Wetlands remove 20% - 100% of metals in the water, depending on the specific metal and the individual wetland. Forested wetlands play a critical role in removing metals downstream of urbanized areas .
Negative Impacts of Human Disturbances on the Functions of Wetlands
Several types of disturbances change the factors that control wetland functions. Changing the: • physical structure within a wetland (e.g., filling, removing vegetation, tilling soils, compacting soils) • amount and velocity of water (either increasing or decreasing) fluctuation of water levels (volume, frequency, amplitude, direction of flow) • amount of sediment (increasing or decreasing)