Integrated water management

An excerpt from UniSC Campus Masterplan 2023

Integrated water management (IWM) is a process which considers all elements of the water cycle (rainwater, stormwater, potable water, and wastewater) as well as collaboratively working with relevant local stakeholders and communities to achieve the best water outcomes for all. IWM planning is currently considered best practice in new and existing facilities in Queensland.

UniSC has adopted the two principles of IWM to incorporate into their planning.
(1) The source of water used should be “fit-for-purpose”, reflecting the quality required for that use, and (2) Water demand management and alternative water sources will be used to reduce potable water demand.

Adopting these principles ensures that the water cycle is managed for multiple outcomes, including alternate water supplies, managing, and recycling and reusing rainwater, stormwater, and wastewater wherever possible, and above all, providing water that is “fit-for-purpose” rather than all water being treated to the highest quality. All elements of the water cycle are considered in the campus IWM Plan, properly identifying water sources, demands, and yields in a way that is consistent with the IWM principles outlined above.

Integrated water management context
History of integrated water management at University of Sunshine Coast, Sunshine Coast Campus

The University has adopted principles of integrated water management since its inception, including one of the first major developments in Queensland to integrate water harvesting and reuse and has implemented continuous improvement in these practices, these are discussed in sections below. Since the 2012 IWM plan the principles of integrated water management have continued to be applied on the campus and support the University’s sustainability achievements. The University now boasts several alternative water projects, saving approximately 50% of the potable mains water that would need to be imported from the Unitywater network.

Relevant legislation and policy

Integrated water management is guided by several laws and policy regarding water management including the Environmental Protection (Water and Wetland Biodiversity) Policy 2019. These documents have informed the development of the Integrated Water Management Plan and will need to be complied with whenever campus development is proposed and undertaken.

Broader catchment / downstream receiving environment
Mooloolah River National Park

The University’s Sunshine Coast campus lies within a sub-catchment of the Mooloolah River National Park (MRNP). Being the park's western neighbour, UniSC (and others within the catchment) have a responsibility to ensure the water quality of the surface flow discharging from their lands does not cause significant impact on MRNP.

MRNP is characterised as a low nutrient environment. Hence, increases in nutrient levels from inflows derived from development at the University and surrounds may result in floristic changes within the MRNP, whereby the changed conditions favour alternate species better suited to higher nutrient environments. This is of concern as the plant communities and associated fauna of the MRNP have extremely high conservation values.

All stormwater flow from the UniSC site and wider catchment currently passes from the site via the two large lakes that exist in the southern portions of the campus. UniSC discharges stormwater across its site boundary in the far south-east corner into another portion of Chancellor Park, before crossing under Claymore Road and entering the National Park.

UniSC occupies an approximately two-thirds of a sub-catchment draining into the Mooloolah River National Park, and ultimately into the Mooloolah River itself. The site receives overland stormwater flow from a section of Chancellor Park, from most of the primary and secondary components of Siena Catholic College, the Chancellor College Primary and Middle Campuses, and the Youi commercial precinct. As such, the lakes provide multiple values, including increasing the aesthetic appeal of the campus and providing habitat. For example, the large expanse of vegetation in the south-west corner acts as a natural vegetated buffer to stormwater flows generated from within the adjacent Sienna College and portions of Chancellor Park, while providing a buffer to neighbouring developments, as well as shelter and food for wildlife.

Features, assets, and opportunities
Drainage / swales

There are two systems used for the handling of natural water run-off on the site aimed at preventing polluted water from entering the catchment.

The first is a ‘closed' system, that is, water is captured and reused within the system. Collection points are within the central zone and include run off from hard surfaces such as car parks and roads. These areas shed the largest amount of water and consequently will transport the highest levels of silt, nutrients, and pollutants.

The water is directed via a system of channels through vegetated swales and collected. From here the water is recycled to supplement the irrigation system providing for such areas as car parks, ovals, and the open campus green. Following these recycling processes excess water passes through further vegetation treatments and eventually is received in two large lakes.

The vegetative filter system assists in disconnecting the hard surfaces and pollutants from the drainage system, slowing down flows, promoting settlement of suspended sediment and adsorbed nutrients, and allowing passive irrigation of vegetation.

The second system is ‘open ended’ and involves the wider landscape of the campus. Although the run-off water from these areas is comparatively `cleaner' than the water run-off from areas more built up, it will be directed to the swale system for treatment before also passing into the lakes. This system, therefore, acts as a protective interface between the University site and the sensitive ecological system of the Mooloolah River National Park.

The swales physically resemble, and operate, as a natural creek system. Techniques to achieve this include the use of soft elements to re-contour and reconstruct the landscape to produce an economical low maintenance system. The use of large woody debris, pond zones and ephemeral vegetation may also serve to reduce the velocity of water run-off, thereby minimising the potential for erosion, which is a problem inherent in the site's friable soil, and to further provide a functioning aquatic ecosystem.

UniSC has Design Standards and Guidelines that provide specific requirements for drainage and discharges (i.e., subsoil, wastewater, stormwater, cooling tower, drains) and targets for stormwater pollutant reduction, as well as a Waste Management Technical Operations Guideline and Hazardous Waste Disposal Process designed to prevent hazardous waste and pollutants from entering the environment at University campuses and sites that also sets out guidance for management of any spills.

Lakes and wetland systems

Wetland treatment systems were recommended as part of the original Campus Master Plan and has been address in the University’s lakes. At the low point of the campus are two lakes with a capacity for 130,000,000 litres of water. The lakes are part of an integrated catchment system that directs storm water run-off through a system of swales and creeks before being collected for storage in two lakes onsite.
The two large lakes should be considered as receiving water, rather than as part of the water quality treatment train. If water quality is not managed prior to entry into the lakes, ongoing and exacerbated water quality problems will arise, and pose a considerable health and maintenance burden on the University.

The lakes on the University campus have been designed to limit flood peaks to that which is generated by the undeveloped catchment area, thereby protecting the hydrological functioning of the campus. This is also an important consideration for Mooloolah River National Park, which is downstream.

Diagram: 4.8.1 Integrated water bodies

Water efficiency measures

UniSC has Design Standards and Guidelines that mandate the use of Australian Water Efficiency Labelling and Standards (WELS) rated fixtures and fittings (6-star taps, 4-star dual flush toilets, 6-star low flush urinals and showers with a maximum resultant flow of 9L per minute) to ensure water use is minimised. Signage is posted in public and office toilets to encourage staff, students, and visitors to turn off the taps and report any leaks.

Asset Management Services conducts regular surveys to locate water leaks on campus and has implemented audit and flow test of all taps and fittings and the installation of water saving devices and efficient isolation points for ongoing plumbing works on campus.

Rainwater harvesting

The University’s Design Standard and Guidelines state that rainwater collection is to be installed on all major projects and used within and around the building to replace use of potable water. An example of this on the Sunshine Coast campus is the recently constructed E block where rainwater is captured in a 5,000-litre underground tank. The water is used to flush toilets and urinals in E block.

Stormwater harvesting

As described earlier, stormwater is treated through a series of swales before being collected in the lake. Untreated lake water is used for irrigation of campus fields. On-site water treatment removes solids and modifies the lake water to produce potable standard water for use as make-up water to the pools, central energy plant and the cooling towers which are a part of the campus air-conditioning system. The University pool also uses an efficient electronic chlorinator.

Since this project has been implemented, the University has achieved a saving more than 20,000 litres of mains water used per day, which also significantly reduces the cost for mains water supply.

UniSC is the first university to use recycled water in swimming pool. In 2015, UniSC became the first university in Australia to supplement 'make-up' water for the 50-metre swimming pool with treated onsite lake water. The treated lake water meets the Australian Standard to Potable Water Classification making it the first project of its kind in the country to be used for this purpose. In 2020, UniSC extended the use of treated lake water to the 25-metre pool.

Irrigation systems

A major goal of the UniSC landscape strategy is to minimise irrigation. For this reason, artificially created irrigation zones are limited in both location and area. Filters between the irrigated and non-irrigated areas are created with intermediate planting. High activity zones are typically sustained by intensive irrigation via an automatic irrigation system, while low use areas and passive zones, planted with predominantly native and endemic vegetation, rely on a combination of the site's existing hydrological cycle, water harvesting from the site and recycling of stored run off in holding ponds. The techniques used range from fully automatic pop-up sprinkler and dripper systems.

A key element of the irrigation strategy is water harvesting, where run-off is collected in the lakes and used for irrigation. This aims to prevent any excess nutrient load entering the National Park and consequently disturbing the equilibrium of its ecosystem. This approach aligns with a plant palette which has the capacity to be self-sustaining and in accord with rainfall levels in the Sippy Downs area.

Thermal Energy Storage Tank

The Central Energy Plant includes a thermal energy storage tank (aka ‘water battery’) to store chilled water for air conditioning. The water is sourced from the same lake system as the pool water but is treated by a different water treatment plant before been cooled. The system is fully automated, and the water quality from the treatment plant is regularly monitored.

Issues and recommendations
Catchment development

Ongoing water quality monitoring shows that the lakes have relatively good water quality. However, at times have shown signs of increased nutrient loads, especially nitrogen, which may result in eutrophication and phytoplankton (algal) blooms. This is likely because of land disturbance activities occurring in the catchment without appropriate management of runoff. It is vital for the health of the lake system, and the functioning of the UniSC water system, that off-site developments focus on water quality management during construction activities and maintain treatment systems.

Flooding

Given the development to the west of the campus emphasis should be placed on examining flood management for the campus, for example, by reviewing peak flow rates of stormwater coming from sites adjacent to the University, and for a determination to be made as to the acceptability of these discharges compared to what was agreed for the site.

If required, further attenuation works such as detention basins should be constructed to aid in the management of peak flows from these neighbouring areas.

The existing fill along the western boundary of the University (between the University campus and Siena College) has been safely “flattened out”, with the loss in flood storage approximately compensated for by improvements in local conveyance characteristics (i.e., by the removal of the fill pile and “dishing” of the area). The regraded region directs flow towards the lake around both the existing and the planned structures, including car parks. The regraded area should continue to be revegetated and have other appropriate erosion and sediment controls employed to limit possible impacts posed by intense rainfall.

The site overall has a relatively even fall towards its south-eastern corner. In general, buildings have been located away from existing drainage channels on the ‘upper’ portion of the campus to the north-west. It is recommended that all new buildings should be located on the ‘higher' portions of the site.

Protecting existing drains

Drainage paths on-site have been extensively modified. Existing low lying drainage paths are recommended to be left undisturbed wherever possible and vegetation regrowth in these areas should be encouraged.

While the upper site drainage paths on-site have been extensively modified because of the development of the University, those on the lower part of the campus below the lakes remain relatively intact. Most of the drainage paths are in reasonable condition and many are heavily vegetated, which presents both water quality improvement and hydrologic benefits.