B4: Groundwater—understanding the interactions between groundwater, surface water and Groundwater Dependent Ecosystems (GDEs)

Melbourne Water makes substantial investments in GDEs, but there is low confidence on the risk of contamination. This project increased understanding of the interactions between groundwater, surface water and GDEs in key locations across the Port Phillip and Westernport region. In particular, it sought to quantify the age and transit time distribution of ground- and surface waters. Melbourne Water also promotes stormwater infiltration as an important strategy in the restoration of baseflows which are typically depleted in urban streams. But there is substantial uncertainty on the fate of infiltrated stormwater. Important research questions included: how much infiltrated stormwater becomes baseflow? and how much is used by downslope vegetation? Another important gap was the potential for infiltrated stormwater to mobilise legacy
pollutants to the stream. This project contributed answers to these questions through an existing ARC Discovery Project.

E5: Community engagement with Melbourne’s blue spaces before, during and after the COVID-19 pandemic.

Melbourne Water, together with its stakeholders, recognises that its waterways, wetlands and estuaries are important for our well-being. In response, we manage these blue spaces for their social values as well as environmental values. During 2020 and 2021, restrictions on residents of metropolitan Melbourne to contain the spread of coronavirus COVID-19 have drastically changed where and how individuals engage with the city and its elements. This project increased understanding of how the COVID-19 restrictions changed community awareness of and engagement with Melbourne’s waterways and other blue spaces. It also helped in understanding why people have engaged more or less with blue spaces during the restrictions, how the use of blue spaces has benefited people and the nature of engagement with blue spaces that participants might have once restrictions are eased and/or removed altogether.

C2: Effectiveness of rural land interventions to improve stream flows and water quality

Melbourne Water’s makes major investments in mitigating the impacts of rural runoff on waterways and the effectiveness of this investment is constrained by limited information on (i) the sources and types of pollutants and (ii) the effectiveness of runoff control measures. This project assessed performance of revegetated swales, sediment basins, and vegetated gullies at dairy farms, including revegetated gullies in the Tarago catchment for treating runoff prior to entering waterways and the drinking water supply. The focus now is on developing or refining tools and products to support management decision-making and stakeholder communications through the Rural Land Management Program.

C3: Effective, efficient indicators for monitoring Water Sensitive Urban Design asset performance

Melbourne Water and their stakeholders invest substantially in stormwater management programs that involve a range of Water Sensitive Urban Design (WSUD) features, however, there is a lack of knowledge about the performance and optimal maintenance of these assets. This project sought to identify cost effective indicators for WSUD performance monitoring, such as low cost sensors and real-time monitoring and control that could be incorporated into new ‘Expert Systems’. The outcomes of this research have now been integrated into other MWRPP research projects including C1 and B3, that will further develop and trial these technologies.

D3: Evaluating direct seeding as a cost-effective revegetation technique

This research project has shown that riparian revegetation using direct seeding has the potential to be more cost-effective than traditional approaches using tube stock planting, particularly sites that are large, flat, easily accessible, and the management goal is mostly about establishing basic vegetation structure. For direct seeding to be successful in riparian areas, there needs to be adequate site preparation, post-sowing weed control, water and herbivore control (also necessary for tube stock plantings). The MWRPP is currently finalising tools and resources to guide the implementation of direct seeding at a range of sites across Melbourne Water in 2020-21.

C4: Understanding the economics of urban water management for improved waterway health to inform effective investment frameworks and to drive regulatory or incentive changes.

This project will place the actions and changes required for waterway protection and restoration into an institutional analysis of the water industry. The approach will permit a formal reconciliation of the beneficiaries and cost-bearers of public, private and toll goods provided by the water industry and common-pool resources, with the primary outcome being a strong case for industry-wide review of integrated water management governance.

2.1: Optimizing flow regimes in the context of a superabundance of water.

This project examined whether ecologically important components of the flow regime can be maintained at levels likely to sustain healthy ecosystems, even when total runoff volume remains significantly higher than natural. The project provided important guidance to Melbourne Water in existing and new urban areas.

4.7: Assessment of Phragmites expansion and control measures at the Seaford Wetlands.

The Seaford Wetlands vegetation monitoring program was established in 2013 to accompany capital works aimed at naturalising water regimes and assisting in the control of Phragmites australis (Common Reed). The program monitored the potential expansion of Phragmites and assessed the effectiveness of slashing as a control measure.