Cities across the globe face long-term challenges from the direct and indirect impacts of climate change and environmental degradation. In light of this, many cities are implementing resilience strategies to ensure that people living and working in cities survive and thrive no matter what shocks or stresses they encounter.
One city leading the way is Sydney, a city of over 5.5 million people and Australia’s leading global city with almost 40% of the top 500 Australian corporations located there.
Sydney facing off with extreme weather events
In Sydney, climate change extreme weather events including heatwaves, storms and localized flooding threaten the city. Of these, heatwaves are found to have the greatest impacts in terms of mortality and the number of people hospitalized. In the future, extreme heat days of over 35 degrees Celsius are likely to increase from 3.5 days per year currently experienced to up to 12 days by 2070.
Meanwhile, Sydney’s rainfall pattern will show significant variability with dry periods followed by deluges of heavy rainfall leading to extensive flood damage to property including infrastructure and buildings. In addition, stormwater runoff carrying pollutants will increase: already stormwater runoff carries nearly 3,000 tons of stormwater pollutants each year into the city’s waterways, damaging the environment.
Sydney’s blueprint for water
As part of Sustainable Sydney 2030, which is the city’s strategy to make the city as green, global and connected as possible by 2030, Sydney has developed a water blueprint that aims to increase the resilience of the city’s water system Click & Tweet! to climate change and environmental degradation. Specifically:
- Water efficiency: Reduce 10% of water demand within the City of Sydney through water efficiency programs by 2030 and reduce 10% of water demand through water efficiency measures in City of Sydney-owned buildings including community facilities, parks, gardens, playing fields and landmarks
- Stormwater quality: Reduce 50% of stormwater pollution by 2030 using water sensitive urban design including raingardens, green roofs or swales to filter and slow down water runoff to Botany Bay and Sydney Harbor
Enhancing water efficiency of businesses
The City of Sydney is working with partners including Sydney Water to increase the efficient use of water Click & Tweet! by all users. For instance, to enhance the efficiency of non-domestic water users, Sydney Water has developed simple benchmarks to help businesses compare their water use with other similar businesses. To do so, businesses:
- Determine their water use (kiloliters per year)
- Identify their key business activity indicator (KBAI), which is a measure of how much water an efficient business uses for specific activities e.g. for commercial buildings and shopping centers KBAI’s include number of customers, total area of retail space (m²), number of employees (table 1), while for hotels the KBAI is number of beds (table 2)
- Divide the kiloliters of water used by the business with their KBAI. This is the benchmark
Table 1. Commercial office building and shopping center business activity indicators
|Ratings||Benchmark with cooling towers||Benchmark without cooling towers|
|Best practice||0.77 kilolitres/m2/ year||0.40 kilolitres/m2/ year|
|Efficient||0.84 kilolitres/m2/ year||0.47 kilolitres/m2/ year|
|Fair||1.01 kilolitres/m2/ year||0.64 kilolitres/m2/ year|
Table 2. Hotel business activity indicators
|Best practice||0.4 kilolitres per room per day|
|Efficient||0.4 to 0.45 kilolitres per room per day|
Overall, benchmarking a business’s water use will help measure performance, identify potential inefficiencies, determine realistic operating targets and enable businesses to better plan for changes such as decreased water availability during long dry spells.
Raingardens reducing stormwater pollution
Sydney has installed 118 raingardens across the city to treat stormwater Click & Tweet! , protect local waterways and green inner-city streets, with most of the raingardens installed when new traffic public works improvements were made to the city’s streets. The majority of the raingardens are located on street corners where cars cannot park and replace what was once asphalt road pavement. The city now has over 2,300 square meters of raingardens that filter out pollution and contribute to the target of reducing sediment reaching the waterways by 50% by 2030.
Being resilient to climate change and environmental degradation means being able to simultaneously manage too little and too much water in the system.
*Robert C. Brears is the author of Urban Water Security (Wiley), and of the forthcoming titles Blue and Green Cities (Palgrave Macmillan) and The Green Economy and the Water-Energy-Food Nexus (Palgrave Macmillan). He is Founder of Mitidaption, which consults on climate change risks to business, governance and society.