Putting Mother Nature to Work: Cleaning Surface Water with Plants
Mother Nature has a solution for almost any malady that affects her. When it comes to cleaning up contaminated small- to medium-sized surface water reservoirs, the remedy is simple to initiate. The result is an area that's beautiful to behold with water that's approved by Mother Nature.
Bring in the Greenery
Aquatic plants are an integral component of a healthy water ecosystem. They are a vital ingredient in the food chain for aquatics and provide habitat for the myriad creatures that living in ponds and lakes. They also perform an essential function in the ecosystem: cleaning and purifying the water.
Living plants are the engine for maintaining a balance in the nutrients and natural chemicals in a water environment. An overgrowth of algae can strangle a small- to medium-sized pond or lake by blocking the sunlight from penetrating the surface, preventing photosynthesis. This turns deeper waters into dead zones with little to no oxygen to support aquatic life.
Plants reduce the amount of algae that's able to grow. They utilize the waste products of fish, serving as a natural filtration system. The right plants can eliminate contaminants such as human waste, household chemicals and industrial pollutants.
The Right Plant for the Job
As with any project, you'll need to the right tool for the job. Which plants to add to a pond or lake depends on the type of contaminants present. Below are different types of plants and which purification jobs Mother Nature has equipped them to handle.
- Shoreline plants: These are sometimes called marginal plants because they grow along the edges of ponds and standing water. One example is water parsley. It reaches heights of 1 to 5 feet tall and can remove a host of heavy metals from surface water. Cattails are a popular shoreline plant that provide habitat for wildlife while clearing water of nitrates, cadmium, zinc, lead and cobalt. They can grow up to 6 feet talk in full to partial shade.
- Grass-like plants: These grass-like plants work to purify the water where they grow. Bulrushes and rushes can grow from 2 to 5 feet tall in full sunlight. Bulrushes are good for removing a general array of contaminants, such as bacteria, oil, organic compounds and nutrients. Rushes are excellent for removing heavy metals such as nickel, manganese, zinc, copper and cobalt.
- Flowering plants: Cannas are easy to grow and produce beautiful blooms in a variety of colors. They grow along the shores and act as natural filters. Water poppies can rise above the level of the level of the water or float on the surface. Their oval-shaped foliage grows well in full sun produces delicate yellow flowers. These perennials love to be in the sun while absorbing nutrients from the water.
- Floating plants: These prolific growers can cover the surface of a pond or lake quickly. Duckweed is a tiny plant that floats freely. It will clear heavy metals from the water and provide a food source for fish and ducks. There are also several species of water lilies, most with broad leaf pads and colorful circular blooms that rise above the water's surface. These floating plants also remove heavy metal contaminants.
Artificial Floating Islands
This method of clearing a contaminated lake was successfully implemented in Fish Fry Lake, 30 miles northeast of Billings, Montana. Agricultural fertilizers and animal waste contaminated the lake and produced an overgrowth of algae. The lake became a dead zone that supported little life.
The solution was plants. Rafts covered with plants were set to drift in the lake. The algae blooms were gone within a year-and-a-half. The water cleared of contaminants and the oxygen level increased. Life returned to Fish Fry Lake.
Mother Nature was probably most pleased.