The Urban Drainage Act 2013 (the Act), defines stormwater as: stormwater means run-off water that has been concentrated by means of a drain, surface channel, subsoil drain or formed surface.
Council’s Role in Managing Stormwater
Council is responsible for the care and maintenance of the public stormwater drainage network within the Sorell Municipality. This includes public stormwater mains, manholes, pits and Council maintained roadside table drains. Council also maintains the stormwater mains owned by Council but situated on private property.
As part of meeting its obligations, Council:
- undertakes assessments of the urban area of the Council’s municipal area;
- documents the stormwater assets under its control;
- conducts frequency-based inspections of its stormwater assets; and
- completes required work on stormwater assets identified during the inspections.
One of the objectives of the Act is to ensure stormwater services, infrastructure and planning are provided to minimise the risk of urban flooding due to stormwater flows. To help meet the objective of providing stormwater systems as may be necessary to effectively drain the urban area of the Council’s municipal area, Council has carried out a 1 in 100 year storm event catchment analysis. This models overland flows and stormwater infrastructure capacity performance of Sorell’s urban areas during a significant storm event.
One of the outcomes of the catchment analysis was a set of recommended options. Council is considering the practicality and financial sustainability of those recommended options.
Types of Stormwater Flow and Responsibilities of Property Owners
Natural Overland Flow
Water that flows across properties due to the existing shape of the land, before any excavation, development or building on the land. An upstream property owner may not be responsible when surface and seepage water flows naturally onto a neighbouring property.
However, the upstream owner may be responsible if the water is made to flow in a more concentrated form than it would naturally flow across the land. Property owners should ensure run-off is directed to Council’s stormwater drainage system or another legal point of discharge, such as the street.
Property owners should always seek professional advice before starting work that may change the drainage and water flow of their property.
Concentrated Overland Flow
Water that flows from hard stand areas e.g. driveways, paths, paved areas, landscaped areas, roofs, drains from roofs, open drains and cut-off drains. A property owner must ensure that stormwater is not discharged from a private stormwater system so that it causes a nuisance to a neighbouring property or its residents.
Seepage (Ground) Water
Water that does not drain into a formed channel or stormwater system. Seepage may be caused be a number of factors, including
- surface run-off from a neighbouring property;
- faulty internal plumbing;
- faults within Council’s stormwater mains or TasWater’s sewer or water mains;
- Natural groundwater.
Individual property owners should ensure they control and minimise the risk of seepage to their properties by taking steps such as the installation of subsoil drains.
Where sloping blocks have been excavated to obtain a flat yard or building site, subsoil drains should be constructed to redirect water to a stormwater drainage system.
Drains and pipes on private property
Property owners are responsible for management of stormwater drainage and surface water within their property. This can be achieved by maintaining roof gutters, downpipes, rainwater tanks, surface channels and other components to minimise the possibility of stormwater entering theirs or their neighbour’s property.
Property owners must accept natural overland flow from adjoining properties or public land and must not divert or redirect the flow from its natural path onto neighbouring properties.
A downstream property owner cannot erect any type of barrier that interferes with the path of stormwater unless provision is made for the flow to discharge to an approved drainage system.
When constructing hardstand areas such as driveways, concrete and paved areas, landscaping and drains, property owners must control the stormwater in order to prevent concentrated overland flows onto adjacent properties.
Property owners generally need to ensure that roof water and hardstand areas are drained to a lawful point of discharge such as:
– Kerb and channel;
– Roadside table drain;
– An inter-allotment stormwater drainage pipe system; and
– Subject to Council approval, a Council controlled drainage easement or drainage reserve.
Council is responsible for regulating private drainage. Council may direct a property owner to connect to Council’s stormwater drainage system or other legal point of discharge.
Property owners need to be aware that fences and landscaping can change the topography of a property and the way it disperses water.
It is the property owner’s responsibility to maintain private stormwater infrastructure. If there is a stormwater issue caused by the failure of your own internal plumbing, contact your plumber.
Reporting a stormwater drain issue
Council receives a number of complaints each year regarding stormwater runoff and overland flow from private property causing an issue to an adjoining or downstream private property. In such instances Council’s intervention powers are very limited and it is likely to be a private civil matter between the adjoining property owners. Stormwater issues regarding runoff and overland flow between private properties should be resolved between those property owners.
You can report any Council related stormwater issue to us on 03 6269 0000. This number can also be used to report urgent after hours stormwater issues.
Where private property has been impacted by stormwater from Council’s drainage network, Council will assess the site and determine whether Council has acted in accordance with its obligations. This includes establishing the cause of the stormwater run-off and determining whether the stormwater assets in the area have been inspected in accordance with Council’s scheduled program and whether any works required to those assets identified during the inspection have been completed.
Below are the flood extent maps for a one in one hundred year flood event.Sorell Council Flood Modelling - 1 In 100 Year Event (9.9 MiB)