The Coffin Bay stormwater “raingarden” was an initiative of the Lower Eyre Coastcare Association (LECCA), the District Council of Lower Eyre Peninsula (DCLEP) and the Eyre Peninsula Natural Resources Management Board, with funding contributed from all three groups.  Prior to the construction of the raingarden stormwater from the largest drain in the town discharged straight into the marine environment and Coffin Bay waterways.

In 2013 the raingarden won a KESAB Sustainable Communities Award. The Sustainable Communities awards showcase hundreds of thousands of volunteer hours and effort towards environmental sustainability, action and improvement in the community. The awards recognise and celebrate positive actions taken by communities, schools, businesses and councils across regional SA to protect and enhance their town and community environment.

The purpose of the “raingarden” is to filter stormwater prior to it entering the marine environment and Coffin Bay waterways. The raingarden is constructed so that during a rain event stormwater runoff from houses, industrial sites and the roads, drains into the raingarden.  The stormwater will slowly filter through the soil profile in the raingarden basin allowing sediments to filter out and settle.  The pollutants targeted are litter, organic matter, coarse sediments, suspended solids, metals and nitrogen.  During large rain events the basin is designed so that the stormwater overtops the basin and flows out through a vegetated swale.  The basin and swale are planted with native vegetation which helps to adsorb nutrients from the stormwater.  The vegetation is planted in bands to ensure that most of the sediment and gross pollutants will collect near the inlet pipe.  These gross pollutants can then be removed and disposed of. 

The raingarden is located within the town centre of Coffin Bay, and as well as being functional it is designed to fit in and complement the landscaping design for the open space.  The wall of the raingarden has been constructed from stone and adds to the aesthetics of the landscaping. The use of native plants also adds to the aesthetics and enhances the biodiversity of the foreshore area.

The coast and marine environments of Coffin Bay have immense conservation value.  Coffin Bay is part of the Thorny Passage Marine Park and an important breeding and calving site for bottlenose and common dolphins.  The coast and marine environments of Coffin Bay are also extremely valuable for fishing, both recreational and professional, oyster aquaculture, recreation and tourism.  Minimising the impact of stormwater into the bay is vitally important to maintain these environments.