Appendix J - Water Supply and Wastewater Servicing Report

Lutheran Services                                                                                           v
PF80 - Cooroy Care Farm
24 May 2018                                                                                Ref. No. 2017.0616




EXECUTIVE SUMMARY
       Introduction
       This report has been prepared by Bligh Tanner to define the water supply and sewerage
       infrastructure required to service the proposed Cooroy Care Farm.
       The site is within the Unitywater area of operations, but is outside Unitywater’s planned services
       area. The facility will need to be self-sufficient with respect to water supply. However, a
       Unitywater sewerage rising main runs to the north of the site and, subject to conditions,
       Unitywater has indicated that the development will be able to connect to this main.
       This report addresses how an adequate supply of potable water will be sourced to meet the
       residential requirements of the facility, how an adequate non-potable water supply will be sourced
       to meet the needs of the care farm, and how wastewater generated within the site will be
       managed.
       Based on the proposed Master Plan, the potential site population adopted for design purposes is
       87.5 EP.
       In addition to the domestic needs of the community, external site uses that will require water
       include site landscaping and lawns, farm areas (gardens, crops, fruit trees) and stock watering.
       Potable Water Supply
       Based on the anticipated site population the estimated residential water demand (excluding
       external uses) is conservatively estimated to be 6.3 ML per year.
       Potable water will be supplied to the facility from harvested rainwater and from an on-site bore.
       A detailed water balance model has been developed to assess the potential for roofwater to meet
       the requirements of the development. The analysis indicates that a total of approximately 850 kL
       of roofwater storage will be required to supply all but 1,000 kL/year of demand on average (ie
       85% reliability). 20-30 kL rainwater tanks will be provided at each building with captured rainwater
       and borewater will be pumped to the central storage and treatment plant.
       A water supply bore has not yet been established on the site, however, preliminary advice is that
       it should be possible to develop a good quality groundwater bore on this site with a yield that
       would make it a good back up supply. Borewater will also be pumped to the central storage and
       treatment plant.
       High quality treated rainwater and borewater will be distributed around the site.
       Non-Potable Water Supply
       The estimated demand for non-potable water for irrigation of crops and landscaping, and for stock
       watering, is up to 13.7 ML/year depending on the extent of irrigated landscaping and the farm
       activities adopted within the facility.
       Non-potable water will be sourced from the on-site dams, and pumped from the dams to a central
       storage tank for distribution to use areas. The supply will require minimal treatment (ie in-line
       filtration) to be suitable for the proposed uses.
       Wastewater Management
       Unitywater has an existing sewage rising main from Pomona to the Cooroy STP that runs
       adjacent to the northern site boundary along Rose Gum Road. Unitywater has provided advice
       that, subject to a number of further investigations and design requirements, a pumped
       wastewater discharge from the aged care facility into the rising main will be allowed. The
       discharge rate would be approximately 1-5 to 2 L/s. The connection to the rising main would be
       completed in accordance with Unitywater’s requirements.