Water conservation achievements Reduction in water use Irrigation For the last few years RBG Melbourne has used only 40-50% of the amount of water for irrigation that was used a decade ago. This has occurred during ten years of sustained ‘driest on record' drought conditions since 1996. We have achieved this through staff training and awareness of water issues, irrigation system development, and improved horticultural practices. The Victorian Government has set total per capita residential water use reduction targets (compared with the 1990s average) of 25% by 2015 and 30% by 2030. Since 2003-04, RBG Melbourne has consistently used less water than both these targets compared with its 1990s average. Domestic With the continuing partnership and support of South East Water Limited, an audit of domestic water use was commissioned for all RBG-managed facilities in December 2005. This has continued to contribute to a reduction of around 20% in domestic water consumption for 2006-07 compared with 2005-06. Overall, there has been a 36% reduction in domestic water consumption since 2001. 
'2008-09 values incomplete and will be finalised by early July 2009'
RBG Melbourne water consumption for irrigation since 1994. The Irrigation Index is a management performance indicator to compare estimated water needs with what was actually used. A value of 1 or less is an "ideal rating". Values higher than 1 suggest overwatering has occurred. Irrigation Association Australia National Conference 12-14 May 2004 Irrigation Association Australia May 2006 national conference presentation Municipal Landscape Irrigation Workshop notes 
  
Awards In 2003, RBG Melbourne won the Sustainable Garden, Garden Design Category of the savewater! awards® http://www.savewater.com.au/ for the Water Conservation Garden. RBG Melbourne was also recognised for efficient water use as one of two finalists in the Efficiency in Government, Government agency category of the savewater! awards®. In 2004, RBG Melbourne was again recognised for efficient water use by winning the Garden Design/Construction Category of the savewater! awards® for the Long Island project. In 2005 and 2006, RBG Melbourne was a finalist in the Gardens Management category of the savewater! awards®. RETURN TO TOP How does the Royal Botanic Gardens conserve water? · 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 Rye grass. Warm-season grasses typically use up to 30% less water than cool-season species. · A weather-based irrigation scheduling system was developed that accounts for plant requirements, end for, climatic conditions, soil water-holding capacity and rooting depths to maintain plant health, rather than promote excessive growth. This approach also increases 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. Over 1000 cubic metres of mulch are applied to garden beds every year. The mulch depth is typically between 50-75mm. The mulch minimises soil water losses from evaporation and improves water-holding capacity of the soil. · The RBG Melbourne uses water-sensitive design principles for all new landscape areas. The Water Conservation Garden and indigenous landscape at Long Island are key examples of this approach. The following collections feature plants adapted to dry conditions: · Arid Collections (cacti and succulents) · Californian Collection · Grey Garden · Cycad Collection · Lower Yarra River Habitat (indigenous plants of Melbourne) · Southern Africa Collection · Water Conservation Garden · Through the use of an Automatic Weather Station, rainfall, solar radiation, air temperature, wind speed and relative humidity are continuously monitored and readings used to estimate the evapotranspiration rate of each plant category in the Gardens. · The performance of the irrigation system equipment, sprinklers and sprays is routinely checked through irrigation audits, and the system is regularly maintained. A well-managed irrigation system ensures a high level of water use efficiency, which saves water. · Irrigation water use is regularly monitored, compared with past years and climatic conditions, and reported monthly across the Royal Botanic Gardens to assist the development of 'water-saving consciousness' in the culture of the organisation.
RETURN TO TOP Landscape Water Management Research The Royal Botanic Gardens has been dedicated to strategically improving landscape water management for over 15 years. It is important to provide this urban water management expertise to others through the internet, presentations, publications and workshops. Read more: Urban landscape water management research RETURN TO TOP How can you conserve water in your own garden? Decide what areas or plants actually need additional watering
Many plants will survive on the water supplied by natural rainfall. For example, locally-native species are adapted to the weather conditions in your area. Many plant species from arid and Mediterranean climates can also survive for long periods without rain or supplementary irrigation. Irrigate your plants according to weather conditions
How often you water your plants will need to be adjusted from week to week. Depending on rainfall, no irrigation will normally be needed for established plantings in winter compared to typically once every 7-14 days in summer. Regularly adjust timers and controllers to ensure the right amount of water is applied at the right time. Group together plants with similar water requirements.
Some plants need more water than others. By grouping plants with similar water requirements, you can help to prevent over- or under-watering individual plants. It can also simplify the design and operation of a watering system.
Choose plants with adaptations that make them natural water savers.
In general, plants with hairy, succulent, wax-coated leaves or with fine, stiff foliage are adapted to growing in dry environments. Grey-or silver-foliaged plants are also usually suited to dry conditions.
Apply a layer of mulch annually to help minimise water-loss from the soil.
Mulch improves the long-term water-holding capacity of the soil and also restricts weed growth that may compete with plants for water. It should be applied in layers from 50-75mm maximum thickness. Mulch that is too thick or too fine will prevent rainfall and irrigation from reaching the soil.
Consider replacing part or all of a lawn with a woody groundcover or change to selected *warm-season grasses or locally native grassland.
Cool-season grasses such as Ryegrass usually need regular watering. *Warm-season grasses such as Buffalo, Couch or Kikuyu use water more efficiently (up to 30% less) and more readily tolerate drought Locally-native grasses are adapted to seasonally dry weather Some warm-season grasses can be environmental weeds and invade natural habitats. Please check if this will be a problem for your local area with horticultural experts or local government prior to planting any of these species in your situation. Water deeply between the evening and early morning.
This is when evaporation from soil and transpiration from plants is at its lowest. Watering deeply provides a larger 'reservoir' of water in the soil and also encourages the development of deep root systems that are more drought resistant. About 10mm (sandy soils) to 30-40mm (loamy soils) of water should be applied to wet the soil to a suitable root-zone depth.
Get to know your garden and its water needs.
Conditions within a garden can vary dramatically. There might be cool, shady areas or hot, dry areas; sections with well-drained soils or boggy soils; sloped or flat areas. Take advantage of this by choosing plants that are suited to the 'local' conditions or microclimates of your garden.
Understand the performance of your irrigation system or sprinklers
There is more to watering your plants than just turning on a tap or setting a timer. A well-designed irrigation system will apply water uniformly and at the correct precipitation rate. High watering rates can result in runoff rather than infiltrating the soil. Check the uniformity and application rate by using a number of catch-cans (pet food tins can be used) spaced evenly between sprinkler heads. Measure depth of water in tins (in mm) after watering .For many soils, the precipitation rate should be less than 10mm per hour. If this is being exceeded, cycle your irrigation by operating for short periods with time for soaking allowed in between. Significant variation of water depths between the catch-cans can suggest poor efficiency. Consider changing sprinkler types and or spacing. The watering diameter of sprinklers should reach each other, or what is termed 'head to head' spacing. Seek irrigation system advice from a Certified or Qualified irrigation designer.
Good maintenance keeps a dry garden in great condition.
Regularly check for pests and diseases, and keep your garden weed free. Ensure that your sprinkler system is operating efficiently to avoid wasting water.
Improve your soil.
In new garden beds, incorporate about 40mm of quality, well-composted, fine organic matter in the top 200mm of the soil profile. This should improve the water-holding capacity of the soil. For established gardens, the regular application of mulch will also improve water-holding capacity by gradually increasing the organic content of the soil.
More water conservation information Royal Botanic Gardens · Irrigation Management Plan (IMP) (Reviewed 2004) (PDF format 1.27MB) · Policy for the Conservation of Plant Biodiversity (PDF format) · RBG Melbourne Water Conservation Factsheet (PDF format) Other information · www.savewater.com.au · www.southeastwater.com.au · Certified Landscape Irrigation Auditors · Irrigation Association Australia Other links South East Water Limited General ways to save water for residents Irrigation Management Irrigation Association Australia Limited “Your Guide to Good Garden Watering” RETURN TO TOP | 
