Water for the Katarapko Floodplain
The specific ecological objectives for environmental watering at the Katarapko Floodplain are to:
- manage water to more closely mimic a natural cycle of flooding and drying
- increase the extent of temporary wetland habitat available for waterbird, frog, turtle and small-bodied native fish breeding and foraging
- improve the condition of long-lived native vegetation that provides important habitat, including river red gum, black box and lignum, and ensure their populations are sustained by encouraging the establishment of new age classes
- provide opportunities for short-lived amphibious and flood-responding understorey plants to germinate and complete their life cycle, enabling them to maintain their seedbank in preparation for the next flood or watering operation
- increase native fish numbers and improve the ability of native fish to move through Katarapko
- enable exchange of nutrients between aquatic and terrestrial ecosystems to fuel the food web and encourage a diversity of water bugs to feed fish, frogs, bats, birds and other floodplain fauna
- improve water quality.
How water delivery works
Floodplain infrastructure
Floodplain infrastructure is used to deliver water for the environment to manage flows and increase water levels through the anabranch creeks to inundate large areas of the floodplain.
Floodplain infrastructure includes:
- a major environmental regulator (The Splash)
- a series of ancillary regulators
- a blocking bank
- fishways (to allow fish to move through the regulators in the floodplain anabranch creeks).
These structures were built through the Riverine Recovery Project and the SA Riverland Floodplain Integrated Infrastructure Program.
How it works
Floodplain infrastructure is operated to gradually raise water levels in the floodplain creeks enabling water to spread across areas of the floodplain that would otherwise be dry during lower River Murray flows. .
Water flows into the Katarapko/Eckert Creek anabranch system from the River Murray, above Lock 4. The elevation difference between pools 3 and 4 provides continuous flow through the floodplain creeks., During a watering operation, water levels are raised behind the major regulators pushing water out through flow paths and over bank to generate broad scale floodplain inundation. The raised water levels are maintained for a planned amount of time before being slowly lowered back to normal levels. Lock 4 is also raised in conjunction with the raising of the floodplain regulators to ensure good flows through the anabranch creeks are maintained.
Operating the regulators
Managed watering events are planned to target a particular height of regulator operation at Katarapko. The regulators can be operated over a range up to over 3 metres above the anabranches’ usual pool level.
The effects of floodplain watering vary depending on the level of inundation we aim for.
| Level of operation | Action |
|---|---|
| Pulse flows and in-channel rise operations with or without natural flows | Pulses of increased flows or raising water levels within the banks of permanent creeks. These actions can occur with or without the concurrent operation of Weir 4. |
| Low level managed inundation | Raising water levels in the permanent anabranches, creeks and wetlands. At some levels, managed inundation can happen without the concurrent operation of Weir 4. |
| Medium level managed inundation | Water extends to inundate low-lying temporary wetlands and shedding floodplain. At medium and high levels of operation, Weir 4 is also raised to assist water flow through the floodplain anabranches to protect water quality while enabling inundation across the floodplain. |
| High level managed inundation | Generates the larger scale watering of wetlands, including reaching temporary wetlands at higher elevations and a larger area of shedding floodplain. |
| During natural flooding | Structures are opened-up so that the natural flows through the anabranch can occur to generate more widespread watering. |
Timing
Planning for the delivery of water for the environment to Katarapko Floodplain occurs each year, in-line with the SA River Murray annual environmental watering plan and priorities (find it here).
The decision to water is made based on floodplain conditions and flow outlook, so watering is not undertaken every year. When delivery is planned, watering most often occurs between mid to late winter through to early summer.
An extensive suite of modelling tools is used to assess potential risks to water quality and estimate the volumes of water required to reach the target inundation level.
Access to the area
When water for the environment is delivered, Katarapko Floodplain will remain open for the public to enjoy, although there may be access restrictions to some campsites and access tracks during higher level operations, as low-lying parts of the floodplain will be inundated.
During watering operations or periods of naturally high river flow, boat passage through the regulators is not possible. However, the creeks and waterways upstream of the regulators will remain open for boating, canoeing and walking.
When the regulators are not operating, the floodplain and creeks can be accessed as usual and small boats can pass between the piers of the Splash regulator.
More information about access and restrictions is available at the Department for Environment and Water Office in Berri and on the National Parks and Wildlife Service SA website.
Does watering work?
Long-term scientific monitoring tracks the ecological condition of the floodplain in connection with the goals listed above. Monitoring also informs decision-making around how we manage delivery of water for the environment.
The monitoring program includes vegetation, fish, waterbirds, bushbirds, frogs, bats, soil, groundwater and water quality.
Highlights from 2023-2024 ecological monitoring
Plants
The strong positive response in River red gum, black box and River cooba tree condition was maintained in 2023-24.
Birds
68 species of terrestrial birds were observed utilising the floodplain.
4 species regarded as uncommon or rare; Gilbert’s whistler, regent parrot, the south-eastern subspecies of the hooded robin, and the nomadic diamond dove were observed.
29 species of waterbirds were recorded, with many of these benefiting from the mudflats exposed by the receding floodwaters.
Fish
1,956 individual fish from 11 species (8 native and 3 non-native) were observed. The most abundant native species were bony herring and the most abundant non-native species were common carp.
2 species of conservation significance were sampled: Murray cod and silver perch.
Small-bodied native fish species comprised 81% of the monitoring catch, including carp gudgeon, unspecked hardyhead, Australian smelt, Murray-Darling rainbowfish, golden perch and bony bream.
High flows at Katarapko 2016
Environmental floodplain watering at Katarapko Spring 2020
How to stay informed
- Sign-up to receive the weekly River Murray Flow Report via email for information on when water levels will rise, expected water level depths and the expected duration. View previous reports.
- Visit the National Parks and Wildlife Service SA website
- Find out how to get involved in environmental water planning by contacting us at dew.ewater@sa.gov.au
- Subscribe to our mailing list to receive updates on your chosen location and hear about opportunities to get involved
- Monitoring and technical reports on WaterConnect
- Pike River Land Management Group on Facebook
