Managing Stormwater Run-off for Landscapes  

Stormwater can be described as any accumulation of water from natural precipitation, including groundwater and spring water, that is transported by an artificial stormwater system, but that excludes potable or wastewater reticulation systems. Stormwater can be a vehicle for various pollutants that may cause damage to receiving water bodies.  

Stormwater management is the administering of control measures to minimize point and non-point pollutants in run-off to protect watercourses. Urbanization has an impact on stormwater quality and quantity due to increased impermeable surfaces that can cause flooding and pollutant run-offs within the urban environment.

To achieve effective stormwater management and mitigate climate change impacts, sustainable urban drainage systems (SuDs) have been adopted. This concept focuses on ensuring a sustainable management of stormwater run-off, considering run-off quantity, quality, amenity, and biodiversity.  One of the practices used is to manage the volume and pollution of run-off in the drainage systems to reduce the possibility of floods (50% reduction) and pollution (as much as 90% reduction). This can also be implemented in residential or commercial spaces, where stormwater can be collected and temporarily stored for the purpose of reducing potable water use. Research shows that stormwater harvesting for irrigation and toilet flushing purposes can potentially reduce potable water usage by more than 20%.   

The use of harvested stormwater as an alternative to potable water usage for irrigation is a water conservation practice. One simple method of harvesting stormwater is the installation of gutters and constructing reasonable sized waterways for transportation of run-off for storage in a retention pond/storage tank. Stormwater can be used to irrigate landscapes and gardens, provided there is an effective maintenance plan for the stored run-off in a retention pond or storage tanks. This is to avoid the development of eutrophication and subsequent effects on landscapes.

Besides the environmental, human and water saving benefits, it has been shown internationally that with a well-designed and managed SuDs system in and around housing developments, the result is approximately 11% lower capital costs when compared to traditional drainage systems. Also, a 10% increase in property and land value can be achieved, while maintenance costs are approximately 20% lower than traditional drainage schemes. More water-saving practices in landscapes and gardens are available on the Water Wise website.   

The Gardener