Types of wetlands
By Kimberly Mullen, CPG
Objective
Students will be able to analyze specific data and determine the type of wetland that it represents.
Introduction
There are many different types of wetlands. Each specific type has unique features that identify it. Some areas have a number of different types of wetlands at one site, even overlapping. Identifying wetlands is a very important task in the world today. There are many laws that protect wetlands by preventing the destruction of wetlands, but in order for the laws to work, wetlands must be accurately identified. Wetland identification and delineation are the only ways of protecting these unique natural features.
Ask the students to list all of the different words they can think of that identify wetlands. Have one of the students record the answers on the board. There are so many different descriptions, many are regionally based (such as muskeg, playas, moors, reedswamp). Pick out the most common names on the list and give a general description for the students. One such list is found below. Classification and definitions can be found on the Internet (two recommendations are www.twingroves.district96.k12.il.us/Wetlands and http://h2osparc.wq.ncsu.edu/info/wetlands).
General information
Types of wetlands (this list is by no means covers every type of wetland, but rather represents the majority of the different categories):
Swamp — a wetland dominated by trees. A swamp is like a wetland within a forest. May form near surface water. Typically about 30 percent of the area must be dominated by trees for it to be considered a swamp. Reeds and grasses may grow along the edge of the swamp. Swamps are found in many different climates (ranging from Florida to Maine and west). pH levels are 5 to 8. High ground water levels. Dissolved oxygen levels typically vary from 2 ppm to 9 ppm. Hardness based on soil/rock type in area. Temperature also is variable (based on location).
Marsh — a continually/frequently inundated wetland that is dominated by emergent, herbaceous vegetation. Marshes typically are shallow with few floating plants. Marshes may form near surface water (such as a stream). They are the transition between land and water. pH levels are 5 to 8. High ground water levels. Dissolved oxygen levels typically vary from 3 ppm to 10 ppm. Hardness based on soil/rock type in area. Temperature also is variable (based on location).
Bog — a peat-accumulating wetland with no significant inflow or outflow of water. Meteoric water is the main water source. High ground water level. Low mineral content in soil and water. High level organic material (decomposing). Highly acidic (low pH) mostly from sulfuric acid. Thick masses of sphagnum moss may be present. Dissolved oxygen levels typically vary from ND (nondetectable) to 6 ppm. Hardness levels vary from 10 ppm to 65 ppm (based on soil/rock type in area). Temperature is also variable (based on location).
Fen — a peat-accumulating wetland with drainage or connections to the ground water. Supports marshlike vegetation. High mineral content in water and soil that feeds the fen. High ground water level, occupies a low point of relief. Rich in Ca, Mg, Ma, K. Low acidity (high pH). Marl may be present. Dissolved oxygen levels typically vary from 2 ppm to 8 ppm. Hardness ranges from 40 ppm to 95 ppm (based on soil/rock type in area). Temperature ranges from 50 degrees F to 57 degrees F (because of ground water contact).
Tidal marsh — a continually/frequently inundated salt water wetland that is dominated by emergent, herbaceous vegetation. Tidal marshes typically are shallow and form in transition areas between land and water (surrounding salt water bays, mouths of rivers, tidal pool areas). pH levels are 6 to 8. High ground water levels. Dissolved oxygen levels typically vary from 3 ppm to 10 ppm. Hardness based on soil/rock type in area. Temperature also is variable (based on location).
Prairie potholes — shallow marshlike ponds formed in glacial depressions (such as kettles and depressions near moraines). Range from New York to Montana. High ground water levels. Dissolved oxygen levels typically vary from 3 ppm to 7 ppm. Hardness ranges from 30 ppm to 80 ppm (based on soil/rock type in area). Temperature ranges from 50 degrees F to 57 degrees F (if fed by ground water).