Current Water Sensitive Performance
Dubbo, a regional city 388 km west of Sydney, is home to approximately 51,000 people. It also services many of the smaller nearby towns and is a major transport hub for people travelling between Melbourne and Brisbane.
It is located within the Macquarie–Bogan catchment, which is part of the Murray–Darling Basin. Its main sources of potable water include the Macquarie River (accounting for around 70% of supply) and bore water (accounting for the remaining 30%). The region experiences 20–30 hot days every year (when temperatures exceed 35oC), and this number is expected to increase.
Change strategy: how to become more water sensitive
Dubbo Regional Council is committed to increasing the urban tree canopy within the city’s central business district (CBD) via the Dubbo Street Tree Masterplan, which guides improvements to the quality and extent of the urban forest canopy.
The Dubbo Health Island Amelioration project is located on Bultje Street (between Darling and Brisbane streets). The project aims to increase Bultje Street’s tree canopy by 300% (up from 2.8% of the total area). The project also uses water sensitive urban design to capture stormwater runoff from nearby streets, to provide a passive and non-potable source of water for irrigating the trees.
The CRC for Water Sensitive Cities applied its TARGET (The Air-temperature Response to Green/Blue infrastructure Evaluation Tool) module of its Scenario Tool to quantify and help visualise the benefits of increasing the tree canopy. This module assesses the air temperature and human thermal comfort of a given site, for example, assessing what happens to urban heat if hard surfaces are converted to natural ones or if unirrigated surfaces are converted to irrigated ones.
The modelling shows the expanded tree cover will reduce Bultje Street’s land surface temperature during heatwaves from 58oC near hard surfaces (e.g. buildings, roofs and asphalt) to 38oC under and near tree canopies. The tree pits will also reduce water quantity and pollutant loads discharging to the Macquarie River.
Research relevant to Dubbo
- The Dubbo Urban Heat Amelioration Project used the Scenario Tool to quantify and help visualise the impacts improving street tree coverage in one of Dubbo’s busiest streets (Bultje Street).