What is Stormwater?
Stormwater is the water that runs off pavements, roads, roofs, gardens, parks, car parks, construction sites etc during rainfall. As stormwater water flows, it collects pollutants such as oils, pathogens (bacteria), litter, nutrients, metals and sediments. This polluted water washes into our rivulets and stormwater systems, ultimately discharging to the recreational water of the Derwent Estuary. Stormwater pollution has a significant impact on the aquatic "health" and recreational uses of both the rivulets and the Derwent Estuary.
(Source: Derwent Estuary Program - Rivulet & Stormwater Monitoring Program, August 2002)
Council's stormwater system is affected when people put unwanted liquids, wastes and materials etc down the drain or on the roads, which then flush to the drain(s) with rainfall.
It is vital that people consider what is being put down the stormwater system. This all impacts on the water quality at the end of the catchment, which can often be a popular swimming beach. This is an issue for not only humans, but also for aquatic organisms. Animals can also detrimentally suffer from the result of people's actions.
Examples of items that SHOULD NOT end up in the stormwater system include:
- Litter of any kind
- Dog faeces
- Cigarette butts
- Detergents and chemicals
- Soapy water from washing cars
- Grass clippings and vegetation
Investigation and Monitoring
Council staff investigate reported problems with the stormwater system. This will sometimes include bacteriological sampling to identify the presence of any potential faecal contamination. Infiltration issues are dealt with by Council's Works Department.
Stormwater Task Force
Council Environmental Health and Engineering staff are representatives on the Derwent Estuary Program (DEP) Stormwater Task Force.
The DEP formed the Stormwater Task Force in 2001 with representatives from Hobart's regional councils, community groups and the Department of Environment (DPIWE).
The main objectives are to:
- Implement a coordinated stormwater monitoring program
- Prioritise stormwater management areas in the region
- Develop a 'model' Stormwater Management Plan (SWMP) for Councils to use as a template
- Share experience in stormwater management
- Assist in grant proposals for management initiatives
- Review stormwater management initiatives
The Derwent Estuary in Hobart receives stormwater from 13 major streams and 270 outlet pipes. Identified stormwater problems include:
- Suspended sediments (muddy water)
- Litter, particularly cigarette butts
- Faecal bacteria (pathogens from sewage or dog poo)
- Oils and heavy metals from road runoff and cars
- A lack of coordinated stormwater management between municipalities
- Little community education on how everyday activities impact our waterways
(Source: Derwent Estuary Program 'Stormwater Task Force')
Soil and water management
Soil erosion on development sites can be a major source of water pollution. Soil, sand, sediment, litter and other materials or chemicals washed from sites can cause short and long term problems for our natural waterways.
Effective on-site soil and water management during development followed by effective site rehabilitation provides great benefits to the entire community.
The document "Guidelines for Soil and Water Management" was developed by the Hobart Regional Councils and can be obtained on request from Council.