09/01/2020
FILTER OUT PLASTICS FROM GHANA's WATERWAYS
For many years, Ghana’s lakes, rivers, streams and water ways have been polluted to the point where many are not swimmable or fishable.
Over the last couple of years, many organizations and communities have drawn attention to these water resources, especially the mining areas which triggered the temporal ban on small scale mining. Some have seen some improvement, and others are yet to be tackled. Tourists have always been attracted to Ghana's coastline tourism potential but the issue of plastic pollution has been the main setback in tapping into the vast potential it offers. For tourism in Ghana to become attractive, our waterways need a facelift for their many recreational opportunities.
Precipitation can do three things when it lands on the ground during a rainy or dry season. Thinking back to our school days and the water cycle, we know it can evaporate back into the air, it can soak into ground becoming part of the groundwater found below the surface or it can run off directly into local rivers, streams, lakes and drainage ditches. Because water is a universal solvent, it picks up anything on the ground as it makes its way to the nearest surface water. That may be fertilizer, pesticides, oil, gas, trash.
All of these go into our waterways along with the water runoff. As the amount of impervious surface increases (sidewalks, parking lots, driveways, roads, rooftops), the amount of land for infiltration decreases resulting in increased run off and potentially more pollution into our surface water.
A bioswale is one way to protect our surface waters by decreasing stormwater runoff. It is a gently sloping vegetative swale designed to slow and reduce stormwater runoff while filtering out pollutants. Bioswales are frequently placed at or near parking lots to capture pollutants from cars preventing it from being carried into nearby waterways after a storm. But bioswales can also be located near waterways to prevent stormwater runoff from entering there. The drainage path, along with the vegetation, is designed to maximize the amount of time stormwater remains in the bioswale. The longer stormwater can stay in the bioswale area, the more pollutants are filtered out.
The benefits of a bioswale on water quality include:
- Protects local waterways from stormwater pollutants
- Creates habitat for wildlife, including birds and butterflies,
- Reduces non-point pollution by filtering stormwater
- Reduces standing water (puddles) that can attract mosquitoes
- Creates colorful gardens with a variety of flowers and plants year round
- Requires little maintenance after establishment
Bioswales are usually planted with a variety of native plants. These are plants that have historically grown in the region. Native plants have deep roots so they can absorb stormwater and filter out pollutants, also known as “non-point source” pollution.
Non-point source simply means the source of the pollutant cannot be easily identified. It can come from many sources.
Point source pollution, conversely, means the pollution’s source can be identified, such as a failing septic system, a leaking storage tank, etc.
Native plants also can create mini ecosystems that can provide food sources for wildlife and insects. Some common native plants that work well in bioswales include vertiver, citronella, lemongrass and moringa.
