A riparian environment, as regulated by DuPage County, is the vegetated area within the regulatory floodplain that provides habitat for vegetation and/or wildlife dependent on the proximity to water. Riparian areas in DuPage County are often dominated by tree and shrub species.
- Vegetated riparian areas help to slow the water down to allow some infiltration. This also helps to remove sediment and pollutants that would otherwise make their way into the river system. Native vegetation benefits landowners downstream by slowing floodwater during a storm and reducing damage to property.
- Many native plants found in riparian areas have deep roots that help to prevent stream bank erosion by holding the soils in place.
- These areas provide essential access to fresh water, food and safe travel for wildlife. These corridors are especially important in an urban environment.
- Forested riparian areas provide cover that helps maintain cooler water temperatures and encourages fish and aquatic species to use these areas for spawning.
Wetlands generally include swamps, bogs, marshes, wooded wetlands, ponds, streams, wet meadows and similar areas. “For regulatory purposes under the Clean Water Act, the term wetlands means ‘those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas.’[taken from the EPA Regulations listed at 40 CFR 230.3(t)]” Click here for more information about wetlands definitions from the U.S. EPA.
Three factors are used to determine the presence of wetlands (according to the 1987 Army Corps of Engineers Delineation Manual):
- Hydric Soils - Soils which present certain characteristics when saturated
- Hydrophytic vegetation – Plants which grow in water or saturated soils
- Hydrology - Soils saturated with water
Many people think that a wetland must have standing water and cattails. In reality, there are many different types of wetlands.
Wetland indicator maps are available at DuPage County for public use, although not all wetlands have been mapped. These maps are available to the public and may be viewed by visiting our office on the second floor of the administration building at 421 N. County Farm Road, Wheaton, IL 60187.
DuPage County wetland specialists may be available to perform wetland determinations for private property owners for a small fee. Please contact the Division of Environmental Concerns at 630-407-6700 for more information on this service. You will be asked to submit a completed request form and payment. Depending on the season, staff will complete your request within 2 weeks time and provide a letter with their findings. It is important to remember that a wetland determination will verify the presence or absence of wetlands only. A wetland delineation is necessary to determine the size and location of a wetland. Wetland delineations are not currently performed by County staff, but you may contract with an environmental consulting firm.
Wetlands help to filter pollutants out of the water and filter nutrients into the soil, enriching the soil for future plant growth. When water flows through thick wetland vegetation and open water, it slows down allowing sediment and certain pollutants to settle to the bottom. Over time, the sediment becomes incorporated into the wetland soil. Over a very long period of time, sediments build up so much that the wetland may fill in and eventually become dry land. This process is called natural succession.
Pollutant Removal
Wetlands help to filter pollutants out of the water and filter nutrients into the soil, enriching the soil for future plant growth. When water flows through thick wetland vegetation and open water, it slows down allowing sediment and certain pollutants to settle to the bottom. Over time, the sediment becomes incorporated into the wetland soil. Over a very long period of time, sediments build up so much that the wetland may fill in and eventually become dry land. This process is called natural succession.
Flood Control
Wetlands can contain and slow down large amounts of water runoff from heavy storms resulting in less flooding. In fact, one acre of wetlands has the potential to store 1 to 1 ½ million gallons of floodwater!
Groundwater Regeneration
Wetlands also help to regenerate our groundwater supply by filtering stormwater runoff though the system to remove pollutants and returning it to underground aquifers. When water is allowed to pond in a wetland, it may begin to soak into the soil to an aquifer below. The soil acts as a filter which removes most contaminants before it reaches the groundwater supply.
Habitat for Plants and Animals
Many species of animals and plants depend on wetlands for habitat and nourishment. Birds use wetlands for nesting and migratory purposes. Nearly half of all endangered species depend on wetlands for survival! Wetlands also provide habitat to diverse plant life. Wetlands make up approximately 5% of land in the continental U.S., but almost 1/3 of our plant species can be found in wetlands.
Wetlands, wetland buffers, riparian areas and regulatory floodplains are all know as special management areas, which require additional documentation before they are altered.
- Building unpermitted structures, including fences or sheds.
- Disturbing the ground or grading without a permit.
- Removal of vegetation without a permit and restoration plan.
- Creating brush/landscape waste or refuse piles.
- Mowing in a natural area.
- Planting non-native vegetation in or around the wetland or buffer area.
- Any activity that negatively affects the flow or absorption of water.
The DuPage County Stormwater and Floodplain Ordinance set specifications for development in special management areas. Find more information on each area and permitting.
DuPage County has published multiple resources for residents living near naturalized areas. Access the library of stormwater management publications.
West Nile Virus is a serious disease which affects the central nervous system. The virus is transmitted by mosquitoes and, in a few cases, blood transfusions and organ transplants. One species of mosquito, Culex pipiens, is thought to be the primary carrier of the disease. Culex pipiens prefers to breed in the stagnant water in containers that collect rainfall, such as birdbaths, children's toys, buckets, gutters, catch saucers for potted plants, etc. Culex pipiens does not typically live in wetlands. Another mosquito, Aedes vexans, sometimes referred to as the Inland Floodwater Mosquito, is found in floodplains and wetland across Illinois.
To minimize mosquitos around your property, keep gutters, toys, and catch saucers clean and free of water. If you live near a floodplain or wetland, consider creating a management plan to improve the health of the natural area. Wetlands and floodplains that are healthy and planted with a diversity of native vegetation are home to mosquito predators such as dragonflies, damselflies, bats, and others. Take care to research the proper way to manage a natural area. The Division of Environmental Concerns provides permitting information and requirements.
