# What is Mitigation?

For technical and legal explanation, see Chapter 62-345 F.A.C. and Section 373.414 F.S.

Florida’s wetlands
those areas that are inundated or saturated by surface water or ground water at a frequency and a duration sufficient to support, and under normal circumstances to support, a prevalence of vegetation typically adapted for life in saturated soils. Soils present in wetlands generally are classified as hydric or alluvial, or possess characteristics that are associated with reducing soil conditions. The prevalent vegetation in wetlands generally consists of facultative or obligate hydrophytic macrophytes that are typically adapted to areas having soil conditions described above. These species, due to morphological, physiological, or reproductive adaptations, have the ability to grow, reproduce or persist in aquatic environments or anaerobic soil conditions. Florida wetlands generally include swamps, marshes, bayheads, bogs, cypress domes and strands, sloughs, wet prairies, riverine swamps and marshes, hydric seepage slopes, tidal marshes, mangrove swamps and other similar areas. Florida wetlands generally do not include longleaf or slash pine flatwoods with an understory dominated by saw palmetto. and other surface waters
water upon the surface of the earth, whether contained in bounds created naturally or artificially or diffused. Water from natural springs is classified as surface water when it exits from the spring onto the earth's surface. are important because they perform many functions necessary to support the natural environment and our quality of life.

Important functions of wetlands and other surface waters include:

Water quality – bacteria, plant life and soil conditions found in wetlands and other surface waters provide highly efficient, natural filtration of rainwater and storm runoff. Wetland bacteria and plants remove nitrogen, phosphorous and other pollutants from surface water. The filtered water is then slowly released into streams, lakes, oceans and aquifers. This filtration prevents algal blooms, fish kills, dead zones and contamination of our drinking water.

Habitat – wetlands and other surface waters provide spawning ground, nesting areas, rich food sources and drinking water for many kinds of animals and plants. Some of these plants and animals are directly important to our human economy and recreation (shrimp, gamefish, ducks, alligators, wading birds, etc.). Many others are food sources that support the economically important species.

Flood control – wetlands and other surface waters are generally found in the lowest areas of the landscape. This means that they naturally collect and store water from storms and prevent that water from flooding the higher areas that are used for residential, commercial and other types of human development.

When a wetland or other surface water is filled or impacted for any reason, its important functions are lost.

Q. How are the functions lost, and why does it matter?

Water quality – when a wetland is filled, it no longer supports the bacteria, plant life or soil conditions necessary for natural filtration of water. Instead, the area becomes a source of nutrient-laden runoff that must go to other wetland areas or a stormwater
the flow of water which results from, and which occurs immediately following, a rain event treatment system. When the wetland or other surface water is impacted but not destroyed, the natural filtration capacity is reduced.

Habitat – wetland habitat is no longer available for wildlife or plants after being filled or converted to another use. The animals that used the area for food, spawning or nesting must find somewhere else to go. The plants that once grew in the area are usually destroyed.

Flood control – when a wetland is filled, it can no longer store water from storms or runoff from surrounding areas. Instead, it now becomes a source of runoff and the water it once stored must go somewhere else or be treated artificially in an onsite stormwater system.

Q. My project is small – why do I have to provide mitigation?

It might seem that one project won’t make much of a difference to Florida as a whole, but think about how many wetland areas all over Florida have been or will be converted to other uses. Every time a wetland or other surface water is destroyed or impacted, we lose some water quality, habitat and flood control. It adds up quickly. If nothing was done to make up for this loss, our water quality would continually get worse, our wetland dependent species that we count on for food or recreation would disappear; and our homes, parks and businesses would be at greater risk of flooding. That situation would not only degrade the quality of our natural environment, but also pose serious threats to human health and safety.

Q. So how do we make up for the losses?

Avoidance and minimization is the first step. Avoiding wetland impact means moving the proposed project to an area where it will not impact wetlands or other surface waters. If the project cannot be moved completely out of these sensitive areas (avoided), then the remaining impacts must be minimized. Minimization means taking steps to make any unavoidable impacts as small as possible. Minimization can include making a building footprint smaller, using pilings instead of fill
depositing material by any means in wetlands or other surface waters. in wetlands, or rearranging the way a project is planned to make the impact area smaller.

To make up for any remaining impacts, mitigation is used.

Mitigation is making up for loss of wetlands and other surface waters, improving public health and safety by creating, enhancing, preserving or restoring wetlands somewhere else when we cannot avoid impacting wetlands for our projects.

Q. How do I know how much and what kind of mitigation I need?

Not all wetlands or other surface waters function equally. Some have different functions than others and support different kinds of wildlife or plant life. Each wetland or surface water filters water, nutrients and toxins in a unique way and releases water to different places (a lake, stream, pond, ocean or directly to an aquifer). Some are higher quality and perform more functions than others. Some types of wetlands and other surface waters are rare and especially important to protect. To be fair to the public and to the environment, Florida uses a scoring method called the Uniform Mitigation Assessment Method (UMAM) to figure out the value of a wetland based on its quality and the functions it performs.

UMAM takes into consideration the drainage basin
an area of land from which a river and its tributaries drains the rainwater. A land area that contributes runoff to one main waterbody, such as all the land area that eventually drains into a certain river, bay, or lake. where the wetland is located, type of wetland, its environmental contribution, and its importance to wildlife and to human health and safety. Three categories of wetland functions are assigned a quality point score on a scale of 0 (no quality) to 10 (best quality). The three categories are location, hydrology (water functions) and community structure (plant and animal life).

A wetland in a good location (surrounded by forest), with good water functions (filters and transports water effectively) and a natural or intact plant and animal community will receive more quality points than a wetland in a poor location (surrounded by development), with reduced water functions (ditched or drained) and a disturbed community structure.

When a person wants to impact a wetland or other surface water for development or other reasons, the impact area is scored before development using UMAM and assigned a number of points (functional score). Development of the wetland will take away or reduce these points (functional loss). The points that are lost must be made up. Points must be created somewhere else (functional gain).

Q. How does that scoring work?

The wetland that is to be impacted is given a point score before impacts. It is then scored again, after impacts. The difference between the before and after impacts score is considered “functional loss” and is multiplied by the acreage of impact to determine how many quality points a person must make up somewhere else. That somewhere else – the area to be created, enhanced, preserved or restored - is called the mitigation area.

UMAM is also used in the same way to score the mitigation area. The mitigation area is given a score before mitigation activities are complete, and then another score considering the enhanced wetland functions after mitigation is complete. The difference between the scores before and after mitigation is considered “functional gain” per acre and is used to determine how many acres of mitigation a person needs in order to make up their functional loss.

Q. What kind of mitigation can I use?

On-site mitigation - You can create, enhance or preserve the remaining wetland area on the project site.

Off-site mitigation - You can create, enhance or preserve wetland acreage somewhere else, as long as it is within the same watershed or drainage basin, performs similar functions and is the same wetland type as the wetland being impacted.

Mitigation bank - You can purchase credits (functional gain points) from a mitigation bank. The mitigation bank creates, enhances, restores and preserves wetlands in a large area and then sells the functional gain points it earns to people who are impacting wetlands to make up for their wetland impact.

To learn more about wetland functions and UMAM, please see these sources:

Environmental Protection Agency Watershed Academy Web - "Wetlands Functions and Values"

Florida Department of Environmental Protection Wetlands Mitigation Section

University of Florida, IFAS Extension - "What is a Wetland?"