Functioning natural ecosystems are vital to maintaining healthy water catchments, and a critical part of how water utilities can manage the delivery of safe, clean drinking water to customers.
As one of South Australia’s largest landholders, SA Water manages around 76,000 hectares of land across the state, with around 20,000 hectares reservoir reserves land – the equivalent size of 10,000 AFL football fields.
Using the skill and expertise of a dedicated environment team, SA Water strives to be a proactive environmental leader by using a wide variety of land management practices to protect water quality and sustain a thriving natural environment.
Managing bushfires to protect water catchments
A key focus of SA Water’s land management practices is bushfire management, with the utility’s long-term approach involving ongoing activities of prevention, preparedness, response and recovery.
Prescribed burning is a critical component of managing bushfire risk on SA Water land, and a strategic burning program, in partnership with the South Australian Department for Environment and Water and relevant fire authorities, is the most effective and environmentally sensitive way to reduce fuel loads across large or complex landscapes.
The importance of SA Water’s fire management practices was recently highlighted by bushfire damage to part of South Australia’s largest reservoir reserve, Mount Bold, with an estimated 1,905 hectares of the 5,500 hectare reserve burnt during the Cherry Gardens fire in January 2021.
SA Water’s Manager Land, Catchments and Recreation, Brooke Swaffer, said the environment team acted quickly to minimise the fire’s impact on water quality contained in the 46 billion-litre capacity reservoir.
“Burnt ash and other organic matter caused by fires like we faced at Mount Bold can cause soil erosion and sediment runoff into water storages, proving a challenge for treatment plant operations,” Ms Swaffer said.
“Following detailed assessments on the fire ground – and when safe to do so – our team assisted in creating sediment barriers out of coconut fibre throughout the network of creek beds, designed to prevent the run-off of organic material into the water source, while allowing native vegetation to regenerate in the soil.
“These structures are considered an interim solution until such time that the native vegetation regenerates, stabilises the ground, and can once again provide the natural filtering properties a native vegetated catchment provides.
“The end result of these measures, together with activities like previous prescribed burning activities at Mount Bold and up-to-date fire break and access track management, ensured our drinking water supply remained safe to drink.
“As a further water quality protection measure, the flexibility of our water network also enabled us to, as a precaution, temporarily reduce reliance on Mount Bold for the supply of drinking water and we also utilised other existing sources including the Adelaide Desalination Plant to supplement supply.”
Maintaining ecosystems through revegetation
One of the pillars of SA Water’s environmental focus is creating a lasting and positive impact on the natural world through sustainable and holistic solutions.
Revegetation of reservoir reserves with native Australian plants and grasses has proven to be an important aspect in creating thriving ecosystems, preventing soil erosion and managing weeds, which in turn work together to improve the quality of water supplied to customers in a cost-effective way.
“Each revegetation project ranges in size and scope, from smaller sites like our Little Para Reservoir, to a large-scale grassy woodland creation at our Millbrook Reservoir, established with more than 2.2 million native grasses and 80 different plant species,” Ms Swaffer said.
“Most recently, our vegetation specialists have planted more than 100 species of native plants and grasses, which are included in a unique project that seeks to reconstruct a thriving grassy woodland which will protect soils in the Clarendon Weir catchment, near the Mount Bold Reservoir.
“The end product has revitalised the land into a thriving ecosystem lush with natives, and forms an important habitat for many species of native birds, reptiles and insects.”
Using new and proven technology to continually improve services for its customers, such as the rapid evolution of drones, is also now a part of SA Water’s way of thinking.
“Like many parts of the business, our team has embraced unmanned aerial vehicles to assist in a range of activities and achieve best results for the South Australian environment,” Ms Swaffer said.
“So far, we have successfully implemented drone technology for vegetation surveys and weed mapping, pre and post-fire vegetation monitoring, and undertaking surveys as part of animal management using thermal cameras.
“As we continue to develop and embed the capability of drones, we’re learning more each day about how they can be applied to the work we do.”