Wetlands are areas inundated by water throughout or during some part of the year. Wetlands absorb surplus nutrients, sediments, and other pollutants before they reach rivers, lakes, or oceans.
They also absorb and slow floodwaters, thereby reducing flood damage. Wetlands provide a habitat for many species of plants and animals. They act as buffers against pollution but excess pollution can harm living organisms within wetlands.
Wetland management involves activities that can be conducted with, in, and around wetlands to protect, restore, manipulate or provide for their functions and values. Natural wetlands are those that do not result from human activities.
The management goal for undisturbed wetlands is to continue existing functions such as buffers for other receiving water bodies. Two main facets of managing wetlands for protection include buffering wetlands from direct human pressures and maintaining natural processes in
surrounding lands that affect wetlands and may be disrupted by human activities.
Wetland Management and protective measures
Protection of wetlands through the assignment of designated use: The level of protection provided should conform to the designated use established for a wetland. Factors to consider in setting the designated use and developing a management strategy for a wetland are;
• Wetland type and landscape location
• Surrounding land uses
• Cumulative impacts on the wetland
• Vegetation quality
• Presence or absence
of rare or endangered species
• Surface water quality
• Wildlife habitats
• Cultural values.
Pressures on wetlands created by humans and other activities:
• Fragmentation of wetlands with roads or other linear facility crossings
• Impacts of recreational uses
• Impacts from adjacent property owners, partial or full wetland owners
• Incursion of trampling, soil compaction, intense grazing, and waste loading
• Pest control treatments, pedestrian access, moving, landscaping waste dumping
• Hydrologic alterations such as ditch construction, dewatering by redirecting contributing land area inflows, impervious surfaces
• increased sediment, nutrient, metals, pathogens, and other pollutant loadings from wastewater discharge
• Changes in physical characteristics of inflows such as temperature, dissolved oxygen, turbidity, and pH due to activities
• Atmospheric deposition of pollutants
• Introduction of nuisance and exotic plant and animal species
• Loss of more sensitive wetland species due to changes in adjacent land uses.
Buffers and other protective measures for wetlands
A buffer consists of a band of vegetation along the perimeter of a wetland or a water body. A buffer design must consider the nature of the encroaching activity, the buffer itself, the resource to be protected and the buffering function to be performed. Criteria for determining adequate buffer size to protect wetlands (Castelle, 1994);
• Wetland functional value-level of disturbance and sensitivity to disturbance
• Intensity of adjacent land use
• Buffer characteristics – vegetation density, structural complexity, and soil condition.
• Specific functions.
Functions of buffers
• Sediment removal
• Nutrient transformations and removal
• Metals and other pollutants’ reduction
• Stormwater reduction through infiltration
• Reduction of water temperature
• Reduction of human impacts by limiting access and minimizing edge effects from noise, light, temperature
• Protection of interior wetland species
• A barrier to the invasion of nuisance and exotic species.
Protective Management of wetlands involves maintaining important management processes that operate on wetlands from the outside and that may be altered by human activities e.g. fire, mosquito control, and construction.