Rainwater Management
As a homeowner, rain is the blessing in disguise that feeds the soul as well as your garden. We all hope for the rainy days where you can stay at home, drink hot chocolate and watch movies the whole day. But rainwater can also be the homeowner’s worst nightmare.
Imagine lying in bed, hearing the rain and waiting for the ceiling to show the water damage or the boundary wall to collapse. Stormwater management is in place to channel the rainwater to the correct places to minimize or eliminate any possible damage due to rain. Rainwater can be soaked into the soil, be stored in dams, ponds, or puddles, evaporate or run off the surface.
Problems are created when the natural infiltration of runoff is interrupted, resulting in increased rates of runoff, which creates erosion and localized flooding. Stormwater running over roofs, driveways, roads and lawns also picks up pollutants such as oil, fertilizers, trash and animal water. When these pollutants get into the stormwater it can flow into untreated local streams, polluting our waters.
Simple Steps
As a homeowner, you can help minimise the damage created by stormwater runoff by following these simple steps:
- Reducing impervious areas so that the rain soaks into the ground.
- Plant native trees and plants that help infiltrate stormwater and increase evaporation and transpiration.
- Managing stormwater on-site with rain gardens and/or rain barrels
Stormwater Generation
In order to determine the best practices for your property, you first need to understand where the stormwater is generated, and how the flow works. The first step is to walk your property and draw the boundaries and basic features.
On the plan, you can indicate the impervious areas (hard surfaces such as parking areas, driveways, patios, decks, etc), the lawn and landscaped areas, natural vegetation (areas that are allowed to grow naturally) and water features such as ponds, streams and swimming pools.
Assess the Flow
The second step is to assess the stormwater flow. Look for telltale signs of how and where the runoff flows. Common problems may include large puddles, damp basements, and soil erosion. Ideally, you should investigate your property after a rainstorm and on your plan indicate the following:
- Rainwater downpipes, and the direction the water flows from the downpipe.
- The flow path of the stormwater up to where it collects.
- Areas of ponding.
- Areas where soil erosion has taken place.
Management
Based on the assessment of the existing stormwater on your property, you can look at a few management practices to better manage the run-off:
Rain Garden
A rain garden is a bowl-shaped garden that can capture and hold water until it is able to be absorbed into the soil. The rain garden is constructed from mulch, soil and deep-rooted native plants to capture, absorb and infiltrate stormwater. A rain garden should be placed a few meters away from any building foundations. A rain garden has great aesthetic appeal with low maintenance. However, it may take a few years to establish.
Riparian Buffer
By planting native trees and shrubs along a stream, wetlands can restore the streamside area to a forested condition. Riparian buffers should also be placed a few meters away from any building foundations, and it is more difficult to implement than some other practices. The buffer increases infiltration and groundwater recharge, improving water quality and controlling erosion and sedimentation.
Native Tree and Shrub Planting
Trees increase infiltration and evaporation of stormwater and require little maintenance. Unfortunately, it may take a few years for trees to grow to provide maximum benefit. A native meadow is an area planted with native grasses, wildflowers and maintained as a natural area. “No mow” areas can also develop into meadow areas.
Redirect Rainwater Downpipes
Redirect the water downpipes to grassed areas of the garden to increase infiltration and groundwater recharge.
Rain Barrels
Rain barrels capture and hold water until it can be used or slowly released into planted areas. For rain barrels to be effective at controlling stormwater, it is important to have a plan for using the water before installing one.
Pervious Pavers
Pervious pavers can look very similar to a traditional brick or stone patio, sidewalk, or driveway. The difference is that they are installed with a thick stone base that provides space for water to be stored until it soaks into the ground. They are great for converting hard surfaces that usually make a lot of stormwater, into a surface that absorbs, manages, and reduces stormwater runoff.
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Carina Botha
Boaz Architects
082 920 3158
