A maintenance schedule is your way of ensuring the health and vibrancy of your bioretention system across its service life, but unfortunately, many bioretention systems remain undermaintained.
Knowing the early warning signs of a system in poor health can help you circumvent costly rectification work or repairs. The efficacy of these stormwater assets is impacted by environmental factors that range from dry periods to flooding and storms.
We examine five key warning signs that your bioretention system needs a maintenance visit and assessment!
Sediment Build-Up & Silt
Unmanaged sediment build-up is the bane of a freeflowing bioretention system, building in forebays and blocking media layers. The accumulation of this sediment may result in the clogging of inlets and restrictions to the inflow of stormwater through the bioretention system.
Sediment build-up is often unsightly and provides an ideal environment for invasive species and weeds to germinate. This sediment can be assessed and removed during routine maintenance.
Ponding and Still Water
Poor drainage results in ponding water, an obvious sign that your bioretention system is not performing well. Often, this may be a result of clogged or damaged underdrains and outlets – which can be rectified with timely maintenance. This saves your bioretention from being unsightly, and minimizes safety concerns such as still water, breeding insects like mosquitos, and drowning hazards.
The growing media in bioretention systems is ideal for plants that treat stormwater – which also makes it a haven for weeds and invasive species. Regular weeding is part of routine maintenance and ensures that these weeds are removed before taking root. It also stops them from competing with the treatment plants, which are responsible for providing root systems that treat stormwater chemically and biologically.
Low Vegetation & Withering Plants
Lack of vegetation or withering plants may have many contributing factors, such as lack of nutrients, poor soil quality and erosion. Particularly in dry environments, or areas with high latent heat such as car parks, an undermaintained or unwatered bioretention system will have withering plants, inhibited growth or even plant death.
Plant Debris & Rubbish
Stormwater often carries pollutants downstream, including plastic waste, gross pollutants, rubbish, and debris. Removing these bulk pollutants is part of routine maintenance – not only does this stop its conveyance downstream, but it also prevents blockages, and improves the aesthetics and amenity of the bioretention areas.