Land Division Fact Sheet 3 Water Sensitive Urban Design

3 sustainable residential subdivision design fact sheet seriesThe District Council of Mount BarkerConstruction, operation andmaintenanceThe construction, operation andmaintenance phases must also be plannedand undertaken in a manner sympatheticto the natural environment. Thepreparation (as part of the developmentapplication) and effective implementationof a Soil Erosion and DrainageManagement Plan (SEDMP) is critical (andrequired by legislation) because it isduring the construction phase that theenvironment is normally placed at greatestrisk.Swales serve a number of functionsincluding:• removing sediments by filtrationthrough the vegetated surface• reducing runoff volumes (bypromoting some infiltration to the subsoils)• reducing erosion, as the vegetationstabilises the soil, and• delaying runoff peaks by reducing flowvelocities.It will also be important to ensure withCouncil that appropriate measures will beput in place for the ongoing operation andmaintenance of WSUD elementsincorporated on the development site.ComplianceIf Development Approval is granted, thedevelopment will be subject to conditions,which must be adhered to and areenforceable under the Development Act.WSUD OptionsAlternative WSUD options, when used inconjunction with conventional practices,have many cost, aesthetic andenvironmental benefits. Some of thesemeasures are detailed below.SwalesSwales are formed, vegetated depressionsthat are often used for the conveyance ofstormwater runoff from impervious areasas an alternative to the use of a kerb andgutter along roadways. They can also beused to convey stormwater flows inrecreational areas.The street crossfall can be designed to falltowards an adjacent swale on one side ofthe street or towards the median strip. Aswale may convey minor stormwaterflows, whilst the carriageway itself isdesigned to convey major stormwaterflows, as it would with a conventionalkerb, gutter and pipe system.Channel WorksEfforts should be made to retain thenatural alignment of any existingwatercourses through open space areas.Where it is necessary to increase channelcapacity, similar alignment and naturalshape should be maintained. Channelsshould be stabilised to avoid erosion,however, concreting of channels should beavoided. Stabilisation methods includeFact Sheet Three - Water Sensitive Urban Design Page 4 of 9