Royal Botanic Gardens is a recognised leader in water conservation for large landscapes. Since 1994, we’ve reduced water consumption at Royal Botanic Gardens by more than 60%.
With more than 10,000 species and 50,000 individual plants at Royal Botanic Gardens Melbourne – including trees and plants of great cultural value; many irreplaceable, endangered or even extinct in the wild – it is important that the survival of these plants is guaranteed by an adequate supply of water.
Through expert management and efficient irrigation, Royal Botanic Gardens has reduced water consumption by more than 60% since 1994. Our horticultural staff have extensive training in current irrigation management principles and efficient operation of the irrigation system.
Turf areas are being converted to warm-season grasses such as Kikuyu, which are more water efficient than cool-season turf like Ryegrass. Warm-season grasses typically use up to 30% less water than cool-season species.
A weather-based irrigation scheduling system is also employed that accounts for plant requirements, climatic conditions, soil water-holding capacity and rooting depths to maintain plant health, rather than promote excessive growth. This means that plants are not watered too frequently – increasing the opportunities to make best use of any rainfall. Efficient irrigation scheduling means that the right amount of water is applied at the right time.
Mulch is used on garden beds. About 1500 cubic metres of recycled plant material is composted to apply 300 cubic metres of mulch to garden beds every year. Mulching minimises soil water losses from evaporation and improves water-holding capacity of the soil.
Royal Botanic Gardens uses water-sensitive design principles for all new landscape areas. The Water Conservation Garden, indigenous plant landscape at Long Island, and Guilfoyle’s Volcano are key examples of this approach.
Strategic Water Plan
The Strategic Water Plan Management Plan 2012–2016 commits the Royal Botanic Gardens to implementing an integrated approach to water management that maintains biodiversity, minimises consumption, evaluates and utilises alternative water sources and demonstrates leadership in efficient water use.
The Royal Botanic Gardens remains committed to reducing its use of mains water at both Cranbourne Gardens and Melbourne Gardens. The Working Wetlands project at Melbourne Gardens has continued with completion of Working Wetlands project, which is expected to reduce Melbourne’s use of mains water for irrigation by 40 per cent when fully operational. At Cranbourne Gardens, development of a water-efficient landscape continues in the Australian Garden with work on developing weather-based irrigation scheduling, including the installation and commissioning of an automated weather station on-site.
The Working Wetlands project aims to revitalise the lake system at Royal Botanic Gardens Melbourne. The current reduced water volume and poor visual quality of the lakes are symptoms of an ecosystem under threat.
The Working Wetlands project will harvest and store rainwater from local storm-water flows, then filter and circulate the stored water to areas within the Gardens. The lake wetland areas will be planted with aquatic species that clean harvested water by removing harmful elements, thus ensuring its quality for irrigation within the Gardens.
These wetland areas will help attract and retain waterbirds and other native aquatic fauna in the lake system. Long-necked tortoises, eels and native water rats will find more cover and a wider range of plants around the water’s edge. Introduction of some sloping gradients to the lake edges will encourage migration and increase populations of frogs. Increased water self-sufficiency will also improve the visual appeal of the Gardens by restoring lake water levels and water flow in Fern Gully, introducing attractive new wetlands, and improving native wildlife populations. The system will be integrated with the redevelopment of Guilfoyle’s Volcano reservoir, which acts as a water storage and distribution facility, a public recreation zone, and an education zone.
The project seeks to reduce the Gardens’ reliance on potable water while maintaining high-quality landscapes and water bodies.