Caring for the Pike Floodplain

About the Pike Floodplain

The Pike Floodplain is located near Renmark and covers more than 6,700 hectares between Paringa and Lyrup.

It is a high priority ecological and cultural area with varied aquatic habitats, fast and slow flowing anabranches and both permanent and temporary wetlands.

The ecological condition of the Pike Floodplain has been declining because of altered flow regimes, elevated and highly saline groundwater, obstructions to fish passage, and pest plants and animals.

Aims for the Pike Floodplain

There is a plan in place for how we manage the Pike Floodplain. The aims of the plan are to:

• foster and promote sustainable irrigation practices
• increase floodplain watering
• maintain permanent wetlands and seasonally variable water levels
• restore flowing habitat
• provide fish passage
• reduce floodplain soil and water salinities
• remove grazing pressure
• promote sustainable recreation.

This plan aims to get stakeholders working together to improve the ecological condition of the floodplain and sustain the local irrigation community.

How we are caring for the Pike Floodplain

Water flows into the Mundic and Pike River anabranch system from the River Murray above Lock 5. The anabranch then flows through the floodplain, bypassing Lock 5, and eventually flows back out to the River Murray in weir pool 4. This along with new infrastructure, provides the opportunity to water parts of the floodplain and improve the condition of the floodplain by managing flows.

For this purpose, infrastructure was constructed including environmental regulators and associated blocking banks to control the flow of water through the floodplain. Fishways were constructed so fish from downstream of Lock 5 can migrate upstream through the Pike Floodplain – something they have not been able to do since the 1930s when the lock was built.

These improvements, delivered by the Department for Environment and Water, were part of the Riverine Recovery Project and the SA Riverland Floodplains Integrated Infrastructure Program.

The Pike Floodplain project

The environmental program delivered by the Department for Environment and Water included construction of regulators, fishways and blocking banks at the Pike Floodplain to improve the overall health and resilience of this landscape. A short film has been created to share the great results of the program and the benefits to the Pike Floodplain and ecosystem. This is the journey of the South Australian Riverland Floodplains Integrated Infrastructure Program (SARFIIP) and the valuable legacy it will leave behind for future generations.

What has been done?

On-ground completed works include:

• • a regulator and fishway at the Deep Creek inlet
  • a regulator and fishway onTanyaca Creek
  • a regulator and fishway on the Pike River
  • 2 smaller regulators at Snake Creek North and South
  • 2 smaller regulators at Mundic Creek North and South
  • replacement of culverts and banks to improve fish passage
  • new blocking banks
  • a groundwater management scheme comprising 26 bores, pumps and underground pipelines.

What happens now?

What are the expected benefits?

• Prevent up to 120 tonnes of salt entering the Pike floodplain each day
• Improve connectivity between riverine and floodplain habitats
• Localised freshening of groundwater systems
• Watering of native vegetation including red gums, black box and lignum
• Improve soil conditions as floodplain watering events flush out salt
• Increase sustainability of the tree population by being able to support seedlings with more frequent watering
• Increase food resources, such as waterbugs and aquatic plants, for animals such as fish, yabbies and waterbirds
• Increase food resources and habitat for native terrestrial animals such as bush birds, reptiles and bats, through improving the condition of the floodplain woodlands.

What to expect during an operation?

Floodplain watering effects vary depending on the level of operation:

• Low: raised water levels in anabranches and creeks
• Medium: water flows out into low-lying wetlands and floodplains
• High: large scale watering of wetlands and floodplains.

How often will watering events take place?

Decisions to operate the infrastructure depend on the condition of the floodplain as well as water quality and flow levels in the River Murray. A high-level watering event may be pursued if the condition of the higher elevation floodplain is declining and there is sufficient water flow available. In years of low river flow, watering events will be less extensive and of shorter duration and will improve the resilience of trees and plants located along the creek system.

How can I stay informed about watering events?

The River Murray Flow Report is a weekly publication. When a watering event is planned or underway the Flow Report outlines when water levels will rise, water level depths and the expected duration. Sign up to receive a copy of the weekly River Murray Flow Report, or view previous reports.

Can I still visit Pike during watering events?

The majority of the Pike Floodplain is Crown Land and some parts of the landscape are protected under the reserve system. Vehicles are not permitted on the Pike Floodplain, however, operations can be seen by walking, mountain biking or kayaking. Some short-term restrictions in access to the landscape will occur during the medium and higher level operations. Information will be provided through the DEW website, the River Murray Flow Report and the Natural Resources Centre Berri to guide the general public.

Will operations affect river salinity?

Over time, river regulation with the construction of the River Murray weirs and a reduced frequency of natural flooding has transformed the Pike Floodplain into a more saline environment with salty groundwater present near the surface. New infrastructure prevents up to 120 tonnes of salt from entering the floodplain each day. Bores, pump and pipelines divert highly saline water to a disposal basin.

Floodplain watering events may increase salt volumes entering the River Murray in the same manner as natural floods by causing saline groundwater to flow into the river. Salinity levels will be tracked and steps will be taken to reduce the impact of any short-term salinity increase, such as using only low-level operations in the first years to ensure salinity remains under established thresholds.

Lead agency

Department for Environment and Water.

Partners

SA Water, Pike River Land Management Group, Renmark-Paringa Council and Renmark to the Border Local Action Planning.

Funding partners

RRP was a $91 million Australian Government initiative to improve the health of the River Murray and its wetlands and floodplains from the South Australian-Victorian border to Wellington.

SARFIIP was a $155 million investment program funded by the Australian Government and implemented by the South Australian Government to improve the watering and management of River Murray floodplains in South Australia’s Riverland.