CEE 210 Environmental Biology for EngineersSouthern Illinois University Carbondale4/17/2010Case Study: WetlandsInstructor: L.R. Chevalier p. 1CEE 210 ENVIRONMENTAL BIOLOGY FOR ENGINEERSCase Study: WetlandsInstructor: L.R. ChevalierDepartment of Civil and Environmental EngineeringSouthern Illinois University CarbondaleEnvironmental Biology for EngineersWhat is a wetland? 1890  1890 federal government report on wetlands "General Account of the Freshwater Morasses of the United States" by Nathaniel Shaler "all wetlands... in which the natural declivity is insufficient, when the forest cover is removed, to reduce the soil to the measure of dryness necessary for agriculture. Wherever any form of engineering is necessary to secure this desiccation, the area is classified as swamp."  Wetlands were viewed as areas that were too wet to farm or too wet to build upon without draining or filling. Environmental Biology for EngineersWhat is a wetland- 21stCentury Area of land with soil that is saturated with water either permanently or seasonally Includes swamps, marshes and bogs Water can be saltwater, freshwater, or brackishFokechik Bay Wetlands, Yukon Delta Environmental Biology for EngineersWhat is a wetland- 21stCentury Wetlands are important ◦ Flood control Storing and decreasing the velocity of excess water during heavy rainfall◦ Collects sediments carried by flood water Protects dangerous build-up of silt that can clog gills or damage eggs of aquatic life◦ Erosion control Buffer shorelines  Roots hold soil, plants absorb impact of waves◦ Filter pollutants, including nitrogen and phosphorus◦ Vital habitat 35% of all plants and animals listed as threatened or endangered live in wetlands, or depend on them in important ways ◦ Recreation and Economy 500 million people observe and photograph birds and wildlife in wetlands, spending close to $10 billion a year on the hobby◦ Remove and store greenhouse gases in the atmosphereEnvironmental Biology for EngineersSurvey of Chesapeake Bay Wetlands plants and animals American Black DuckBald CypressBald EagleBlack-crowned Night HeronMarsh Rice RatCattailsEnvironmental Biology for EngineersEastern Painted TurtleMarsh HibiscusSouthern Leopard FrogSnow GooseGreat EgretMarsh PeriwinkleSurvey of Chesapeake Bay Wetlands plants and animalsCEE 210 Environmental Biology for EngineersSouthern Illinois University Carbondale4/17/2010Case Study: WetlandsInstructor: L.R. Chevalier p. 2Environmental Biology for EngineersDefinitions Hydrophytes◦ Plants adapted to life in water or in waterlogged substrate◦ Only 1/3 of all vascular plants in the US can tolerate wetland conditions Hydric soil◦ Frequently flooded or waterlogged soils associated with wetlands◦ Lakes and rivers have hydric substrate, but do not support free-standing vegetation◦ Characterized by thick organic deposits in the upper areas of soil◦ This anaerobic condition flows down the oxidation of organic matter◦ Grayish subsoils (due to lack of iron ioxides)◦ Mottled soil (graying subsoil with orangish, yellowish or redish mottles, reflecting a fluctuation water table◦ Rotten egg odor (hydrogen sulfide from organic matter decomposition)◦ Black sand (due to heavy organic coating of sandEnvironmental Biology for EngineersTypes of Wetlands Marshes◦ Tidal◦ Nontidal Wet Meadows Prairie Potholes Vernal Pools Playa Lakes Swamps◦ Forested Bottomland Hardwood◦ Shrub Swamps Mangrove Swamps Bogs◦ Northern bogs◦ Pocosins FensEnvironmental Biology for EngineersMarshes: Overview Frequently or continually inundated with water Characterized ◦ Soft-stemmed vegetation that has adapted to saturated soil◦ In general water is from surface water, but many have water from groundwater◦ Nutrients are plentiful◦ pH is usually neutral Benefits◦ Recharge groundwater and moderate stream flow◦ Important during drought◦ Reduces damage of floods by slowing down water and storing water◦ Microorganisms and marsh vegetation use excess nutrients for growth, reducing pollution◦ These marshes are used as models for constructed wetlands used to treat farm wastewater, parking lot run-off and small WWT plantsEnvironmental Biology for EngineersTidal Marshes Influenced by ocean tides Some are brackish, others saline Function◦ Buffer storm seas◦ Slow shoreline erosion◦ Absorb excess nutrients before they reach the oceans and estuaries◦ High concentrations of nutrients can cause dead zones◦ Provide vital food for clams, crabs, and juvenile fish◦ Offer shelter and nesting sites for several species of migratory waterfowlTidal marsh along the Edisto River, South CarolinaThe Great Egret (Casmerodius albus) winters in the tidal marshes along the Gulf Coast. Environmental Biology for EngineersNon-tidal Marshes Most prevalent and widely distributed wetland in N. America Mostly freshwater, although some are brackish or alkaline Frequently occur along streams in poorly drained depressions, and shallow water along the boundaries of lakes, ponds and rivers Water levels vary from a few inches to 2-3 feet May dry out completely, e.g. prairie potholes Soil is highly organic, mineral rich, sand, silt and clay Considered to be one of the most productive ecosystems on earth◦ High diversity of life◦ Mitigate flood damage◦ Filter excess nutrients from surface runoffMuskratEnvironmental Biology for EngineersNon-tidal Marsh: Prairie PotholeCEE 210 Environmental Biology for EngineersSouthern Illinois University Carbondale4/17/2010Case Study: WetlandsInstructor: L.R. Chevalier p. 3Environmental Biology for EngineersNon-tidal Marsh: Prairie Pothole When the last glaciers retreated 12,000 years ago at the end of the ice age, millions of depression were left Over half of the migratory waterfowl in North America depend on prairie potholes for their survival and reproduction Prairie potholes are also sometimes called sloughs They can be found in Montana, North and South Dakota, Iowa, Minnesota and the Canadian prairiesEnvironmental Biology for EngineersNon-tidal Marshes: Vernal Pools Develop from spring melt Dry up as the weather warms Breeding grounds for frogs and other amphibians Some organisms adapt to survival in dry season◦ Algae and protozoan dig into mud, and may a cyst or hard cover our of limeEnvironmental Biology for EngineersVernal