The conservation approach to land development emphasizes open space and uses innovative and environmentally sensitive stormwater management techniques. These natural landscaping techniques contribute to a healthy environment by more appropriately conveying and storing stormwater, resulting in cleaner water in our rivers and streams.

Rainwater has typically been viewed as troublesome, to be disposed of as soon as it falls. (Traditionally, stormwater is managed by designing a road that routes rainwater to the curb and gutter to drain into an enclosed system of pipes that convey it directly to a stormwater detention area as quickly as possible.) This method allows the direct transmission of sediments and oils from roadways and excess fertilizers, and pesticides from lawns, into the system. These pollutants can include dangerous chemicals such as lead, chromium, cadmium, phosphates and nitrates.

Lacking in this method of stormwater management is the natural cleansing of rainwater and pollutants that are harmful to the environment and ultimately to us and our children.

In an ideal situation, rainwater would not be allowed to quickly run off. It would be held and absorbed slowly into the ground, replenishing precious water resources - our streams, lakes and wetlands. When lateral movement or runoff did occur, it would be designed to move slowly across the landscape, through swales and eventually into containment and holding areas.

Today’s typical developed site, however, with its impervious surfaces, compacted soil and traditional lawns, uses curbs, gutters and sewers to quickly remove stormwater, taking with it pollutants picked up along the way. Rainwater with its pollutants, when flushed quickly downstream, results in increased flooding and contamination of detention basins.

On the other hand, in communities with natural drainage designs, the landscape architect and land planner work to imitate natural conditions by maximizing the ability of rainwater to be held and absorbed into the ground.

In order to do this, clustered residential site plans group housing around depressions, swales, wetlands and streams. Land planners identify opportunities to follow the natural lay of the land and allow runoff from streets, rooftops, driveways and parking lots to flow into vegetated areas and ultimately to swales that allow for surface drainage.

A swale is simply an open-air gently sloping ditch. A bioswale is one that has been planted with native vegetation instead of turf grass to maximize retention of runoff from buildings and paved surfaces. The bioswale slows the volume and speed of water on its way to natural waterways, minimizes erosion and maximizes absorption into the ground and evaporation into the air.

The gently rolling terrain of the Midwest is ideal for bioswales in their capacity to serve as appropriate alternatives to storm sewers. Bioswales perform the best when ground slope accommodates wide, shallow corridors that are able to accept a large concentration and flow of rainwater.

Unlike the conventional storm sewer, moving water slowly allows it to be absorbed into the ground. The bioswale is able to direct stormwater back into the ground through the native grasses that are ideal due to their deep roots that absorb water and trap and filter pollutants.

Before runoff leaves the development site, routing it through a detention basin allows for further removal of contaminants. Unlike conventional basins, detention basins that are naturally landscaped make use of native plants and gradual slopes to aid in the removal of pollutants and reduce the need for maintenance.

Natural detention design attempts to duplicate a natural water’s edge with undulating shoreline with mulitple basin shelves planted with native wetland vegetation and nonsymmetrical basin shapes emulating the natural condition and appearance.

Mill Creek, approximately three miles west of Randall Road in Kane County, Illinois integrated nearly 1,500 acres of existing farm fields with a natural landscape of restored prairies, wetlands, meadows and lakes protecting water quality. Restored native prairies and wetlands serve as a natural habitat for wildlife as well as providing an alternative stormwater management system. Rainwater that is not absorbed into the ground, or does not evaporate, flows slowly from the prairies into created lakes and wetlands and ultimately into Mill Creek.

Use of natural landscaping for water conveyance saves money in stormwater piping and installation. Natural landscaping, though not inexpensive, is less expensive to maintain in the long-term than traditional stormwater applications. Initially, maintenance is required until the “grow in” of the natural vegetation is well-established.

Throughout Mill Creek the natural environment has been preserved and enhanced. Wetlands and wildlife corridors have been preserved and wetlands and fence rows have been restored. Water quality has been improved. Bioswales have been used in place of curb and gutter to slow stormwater runoff and provide infiltration and groundwater recharge. Wetlands filter run-off before it enters Mill Creek and regional waterways. Local regulations for stormwater detention have been met through these natural features.

The conflict between urban areas and rural areas has been achieved by providing for a logical transition between them. Rather than impacting natural ecosystems, Mill Creek has sensitively enhanced them.

Appreciation of natural landscaping is an ongoing process. Homeowners are now beginning to appreciate the naturalization of their surroundings and its benefits to the protection of our groundwater resources; wildlife and the community.

Chris Lannert, Lannert Group company president, and Greg Stevens, vice president, are principals and premier planners and landscape architects who served as land planners and landscape architects for Mill Creek.