Mamre Road Flood Riparian and Integrated Water Cycle
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Mamre Road Flood, Riparian Corridor and Integrated Water Cycle Management Strategy October 2020 Acknowledgement of Country Sydney Water respects the traditional ‘Caring for Country’ restorative approaches practiced over tens of thousands of years by Aboriginal people and play our part to improve the health of the landscape by recognising and nurturing all values of water in our environment. In doing so, we acknowledge the traditional custodians and their ancestors of the lands and waters in Western Sydney where we are working and learning: the D’harawal and Dharug nations, as well as their neighbours the Gundungurra. Their lore, traditions and customs nurtured and continue to nurture the sweet waters in this area, creating wellbeing for all. We also pay our respects to Elders, past, present and emerging. Mamre Road Precinct | Flood, Riparian Corridor and Integrated Water Cycle Management Page 2 Table of contents Acknowledgement of Country ............................................................................................... 2 1. Introduction ............................................................................................................................. 8 1.1 Mamre Road Precinct .......................................................................................................................... 8 1.2 Study Objectives .................................................................................................................................. 8 Water Servicing Strategy ............................................................................................................................. 8 Flooding ....................................................................................................................................................... 8 Riparian Corridor Management Strategy ..................................................................................................... 9 Waterway Health (Stormwater Quantity and Quality) Management ........................................................... 9 2. Predeveloped Site Conditions .............................................................................................. 10 2.1 Land Use ............................................................................................................................................. 10 2.2 Topography ........................................................................................................................................ 10 2.3 Waterways and Riparian Corridors .................................................................................................. 10 2.4 Drainage Structures .......................................................................................................................... 10 2.5 Soils and Salinity ............................................................................................................................... 11 2.6 South Creek Wianamatta Floodplain ............................................................................................... 12 2.7 Riparian Corridors ............................................................................................................................. 12 3. Design Standards and Approach ......................................................................................... 13 3.1 State Environmental Planning Policy (Western Sydney Employment Area) 2009...................... 13 3.2 Penrith DCP 2014 ............................................................................................................................... 14 3.2.1 Flood Planning ............................................................................................................................. 14 3.2.2 Stormwater Management and Drainage ...................................................................................... 15 3.3 Draft South Creek Floodplain Risk Management Study ................................................................ 16 3.4 Controlled activities on waterfront land - Guidelines for riparian corridors on waterfront land 16 3.5 Summary of Performance and Guidance ........................................................................................ 17 4. Land Use and Urban Form .................................................................................................... 19 4.1 Industrial Development ..................................................................................................................... 19 4.2 Urban Form and Imperviousness .................................................................................................... 19 4.2.1 Large Format Industrial Sites ....................................................................................................... 20 4.2.2 Business Campus and Strata Industrial ...................................................................................... 22 5. Integrated Water Cycle Management ................................................................................... 24 5.1 Water Demands .................................................................................................................................. 24 5.1.1 Irrigation ....................................................................................................................................... 24 5.1.2 Urban Cooling .............................................................................................................................. 24 5.2 Drinking Water Servicing .................................................................................................................. 25 5.3 Wastewater Servicing ........................................................................................................................ 25 5.4 Stormwater Servicing ........................................................................................................................ 26 5.5 Recycled Water Servicing ................................................................................................................. 27 6. Flooding ................................................................................................................................. 28 Mamre Road Precinct | Flood, Riparian Corridor and Integrated Water Cycle Management Page 3 6.1 Precinct Scale Hydrologic Model Development .................................................................. 29 6.1.1 Rainfall Data ......................................................................................................................... 29 6.1.2 Probable Maximum Precipitation ................................................................................................. 29 6.1.3 Sub-catchment Areas .................................................................................................................. 30 6.1.4 Catchment Imperviousness ......................................................................................................... 31 6.1.5 Catchment Roughness ................................................................................................................ 31 6.1.6 Slope ............................................................................................................................................ 31 6.1.7 Losses .......................................................................................................................................... 31 6.1.8 Catchment Lags ........................................................................................................................... 31 6.2 Precinct Scale Model Results ........................................................................................................... 32 6.2.1 Western Catchments ................................................................................................................... 32 6.2.2 Eastern Catchments .................................................................................................................... 32 6.2.3 Northern Catchments ................................................................................................................... 32 6.2.4 Peak Flows .................................................................................................................................. 32 6.3 Hydrologic Impacts ........................................................................................................................... 33 6.3.1 Local Impacts ............................................................................................................................... 33 6.3.2 Detention Requirements .............................................................................................................. 33 6.4 On-Site Stormwater Detention ......................................................................................................... 33 6.4.1 Modelling Approach ..................................................................................................................... 34 6.4.2 Detention Strategy ....................................................................................................................... 34 6.5 Precinct Scale Hydraulic Model Development................................................................................ 35 6.5.1 Existing Site Model Terrain, Model Extent and Grid Size ............................................................ 35 6.5.2 Post Development Model Terrain, Model Extent and Grid Size .................................................