Constructed Wetlands
France Park’s constructed wetlands were developed to improve the failing septic systems throughout the park. Designed & engineered by J.F. New & Associates and constructed by Leo Brown Construction, Inc. in the summer of 1999, the system is a unique method to treat wastewater before it is returned to the earth and the groundwater below.
Naturalist, Roger Miller, consults with JF New field supervisor, Jennifer Lemler, about beneficial and invasive plants in the wetlands cells.
Wastewater from the park is pumped to the cells. Beneficial plants in the three cells remove nitrogen and send water vapor (evapotranspiration--see explanation below) into the air. Unfortunately, wind and animals deposit seeds that are not beneficial and squeeze out the desired plants. Here, under Roger Miller's direction, Boy Scouts remove invasive plants from the walkways and the cell. Their help is greatly appreciated.
When we use the sink, toilet, shower, or washing machine, we produce wastewater. Wastewater must be treated and cleaned. In the city, wastewater goes through a sewer to a wastewater treatment plant. The treated water is returned to a creek, river or lake. Rural areas often use simple septic tank systems that include a septic tank and an absorption field for the water’s discharge.
Septic systems can fail for many reasons. Often the soil is unable to accept the septic flow. Wastewater pools on the surface. This causes unpleasant odors, pollutes the ground above and could cause people to become sick. Septic systems may not provide enough treatment and pollute groundwater. In turn, this can contaminate wells, which provide water for our daily consumption. These were the problems that faced France Park’s managers.
Constructed wetlands are considered "nature’s environmental filters." Just like nature, this man-made wetland is a natural area that:
 | Has constantly or periodically standing water; |
| Has plant species that thrive in these conditions (primarily- |
| bull rush & sedges); |
| Helps nature by providing habitat for wildlife; and |
| Cleans the water. |
|  |
After the wastewater enters a septic tank (where solids settle to the bottom), it is discharged to the constructed wetland through a centralized sewer line. As water enters the wetland, bacteria that live around the plant roots naturally break down the organic matter in the water. The treated water then drains into an absorption field covered with prairie grasses, called a biofield. In addition, evaporation through the wetland plants (called evapotranspiration) reduces the amount of treated water that is discharged into the biofield.
The benefits to France Park are enormous. The first and most important benefit is that individual septic systems are no longer causing problems and that clean, clear water is being discharged back into the soil. While the initial construction costs were significant for the Cass County Parks Department, the ongoing maintenance will be minimal and inexpensive. In addition, the constructed wetland is becoming a primary visitor destination within the park.
France
Park's Constructed Wetland
Plant Species
Common Name |
Scientific Name |
| Swamp Milkweed | Asclepias incarnata |
| Water Arum | Calla Palustris |
| Tall Yellow Iris | Iris pseudacorus |
| Blue Flag Iris | Iris virginica shrevei |
| Cardinal Flower | Lobelia cardinalis |
| Great Blue Lobelia | Lobelia siphilitica |
| Common Arrowhead | Sagittaria latifolia |
| Bristly Sedge | Carex comosa |
| Bebb's Oval Sedge | Carex bebbi |
| Brown Fox Sedge | Carex vulpinoidea |
| Awl Fruited Sedge | Carex tribuloides |
| Porcupine Sedge | Carex hystericina |
| River Bulrush | Scirpus fluviatilis |
| Great Bulrush (softstem) | Scirpus validus creber |