6.11 Urban Stormwater and Litter

Urbanisation in the towns of Taree, Wingham, Harrington and Old Bar has created large areas of impervious surfaces such as roads, rooves, driveways and carparks. As a result, there is less infiltration of rainfall to ground water, increased stormwater overland flow velocities and greater volumes of runoff (Worley Parsons 2009). Sediment transport is particularly problematic during the construction phase of urban development, when soils are exposed. Over the life of a development 80% of sediment lost occurs during the construction phase. Pollutants typically found in stormwater include litter and microplastics, bacteria, nutrients, petrochemicals, pesticides, heavy metals, sediment and organic matter (NSW Govt. 2009). A preliminary spatial risk assessment for the Manning River Estuary produced for the Manning River ECMP Scoping Study found that pollutant loads from urban stormwater are relatively low compared to catchment loads from agricultural land (MCC 2020). Potential impacts include: • Excess nutrients fuel algal blooms which lead to habitat loss impacting on the abundance and diversity of macroinvertebrates and aquatic fauna • Visual pollution from gross pollutants impacting scenic amenity, town pride, tourism and recreation. • Plastics can mimic natural food sources and injure/kill wildlife including birds, fish and dolphins. • Sediment reduces the amount of light available for seagrass to grow, impacting aquatic fauna. • Organic matter such as grass clippings reduces oxygen levels in the water as it breaks down, killing plants and animals. In Taree, Browns Creek is an identified hot spot affected by runoff from the town centre and residential area which carries litter, hydrocarbons, sediments and nutrients into the creek. In Wingham large catchments with aging infrastructure have led to increased erosion at outlets causing sedimentation in the local waterways, and as hydrocarbons and litter pollution at the Wingham Wetlands site next to the major shopping centre. Management agencies: MidCoast Council (MCC), Hunter Local Land Service (Hunter LLS), DPIE – Environment, Energy and Science, NSW Government. Community: Friends of Browns Creek; Team Taree, OzFish, Mid Coast 2 Tops Landcare. Who’s affected? Private landholders, MCC, DPIE - Crown Lands, community members, fishing and oyster industry.