This layer describes the stormwater priority areas for Melbourne Water’s Healthy Waterways Strategy 2018 (HWS2018). Stormwater priority areas were determined by a combination of decision support tools and the co-design process. The decision support tool used was Zonation, which prioritised management actions across the region with the objective of improving instream habitat suitability for platypus, fish and macroinvertebrates. The stormwater priority area polygons were created by merging sub-catchments from University of Melbourne’s subc layer, i.e. the network of sub-catchments used for assessing attenuated imperviousness and for habitat suitability modelling. Primary purpose for this data is identifying stormwater priority areas of Melbourne Water's Healthy Waterways Strategy 2018. This dataset covers the Greater Melbourne region with the stormwater priority areas presented in this dataset aligning with the priorities of the Melbourne Water Healthy Waterways Strategy 2018. However, it is important to note that stormwater management activities require additional judgement to consider whether areas beyond (e.g. upstream) of the priority areas identified will also require treatment to achieve the desired waterway health outcomes.The harvesting and infiltration targets presented in this dataset provide an estimate of what is required to achieve stormwater disconnection and recreation of the natural hydrology. However, is should be noted that these values are approximate only and do not replace site-specific investigations. The values have been calculated in reference to Walsh et al. 2012 , who presented target ranges for infiltration and harvesting required to achieve urban stormwater disconnection (i.e. re-creation of forested/vegetated hydrology). The values presented are the average of the ranges estimated by Walsh et al. 2012. These values do not replace a detailed site investigation. Site-specific factors (soil type, topography, geology and other hydrological features of the catchment) will influence the appropriate targets for a site.For further reading on the prioritisation process see:Chee et al. (in development), Habitat Suitability Models, Scenarios and Quantitative Action Prioritisation (using Zonation) for Melbourne Water’s Healthy Waterways Strategy: A Resource Document, University of Melbourne and Melbourne Water for Melbourne Waterways Research Practice PartnershipMelbourne Water (in development), Healthy Waterways Strategy Resource Document. Each priority area contains targets for harvesting and infiltration. Achievement of these targets is required to achieve stormwater disconnection. These targets are presented in two ways: per impervious hectare, and total volume to full urban development (i.e. complete urban development to the urban growth boundary). It should be noted that these targets are approximate values only and do not replace site-specific studies. See notes above about how target values were selected.For further reading, see: Walsh, C. J., Fletcher, T. D., & Burns, M. J. (2012). Urban stormwater runoff: a new class of environmental flow problem. PLoS One, 7(9)NOTE: Whilst every effort has been taken in collecting, validating and providing the attached data, Melbourne Water Corporation makes no representations or guarantees as to the accuracy or completeness of this data. Any person or group that uses this data does so at its own risk and should make their own assessment and investigations as to the suitability and/or application of the data. Melbourne Water Corporation shall not be liable in any way to any person or group for loss of any kind including damages, costs, interest, loss of profits or special loss or damage, arising from any use, error, inaccuracy, incompleteness or other defect in this data.