Lake Meran’s health on the improve
A key northern Victorian wetland is showing impressive signs of recovery, half way through a bold rehabilitation plan.
Prior to the modernisation of the Goulburn Murray Irrigation District channel network, outdated and inefficient regulation practices contributed to Lake Meran being kept artificially full of water and caused changes to the wetland’s natural regime.
With Goulburn Murray Water needing to maximise water efficiencies across the Loddon Valley irrigation area for the betterment of irrigators, and a change of management practices after the Millennium Drought; water for the environment is the only water that flows into the wetland outside of a natural flood and small volume emergency channel outfall releases.
That has allowed for the rehabilitation of the lake, with fluctuating water levels bringing plants and native birds back, while protecting an important population of Vulnerable Murray River turtles and native fish.
“The Meran Lakes Complex Environmental Water Management Plan aims to improve the health and condition of the lakes to provide opportunities for all values and users of the wetlands,” North Central Catchment Management Authority (CMA) Executive Manager Tim Shanahan said.
“We are five years into our 10-year plan and the lake is behaving exactly as we thought it would.
“The mudflats around the edges are moist, which is the perfect environment for germination of vegetation such as rushes and sedges, and flowers such as the Threatened downey swainson pea.
“More of these plants means better habitat for frogs and small fish when lake levels rise again. Once water returns, the wetland will boom, as was seen when the southern basin of the wetland was flooded in 2016, after being dry for several years.”
Under the Meran plan, water levels are being managed now to stay within a 50cm range, which means the lake is about 1.5m deep for between 50 and 65 hectares of its area.
“We are getting towards the bottom end of that level, so we will start putting about two gigalitres of environmental water into Lake Meran in the coming weeks,” Mr Shanahan said.
“The water quality is consistent with the needs of the lake, salinity levels are well within the healthy range for the environment and we expect it to remain that way during this top-up.
“We need to balance between leaving enough water in the lake for the fish and turtles, and creating mudflats to allow plants and red gums to thrive.
“The plan, which we developed with significant input from the local community, will see the lake filled in spring 2021, if water is available in the system and unless it floods in between times.”
Mr Shanahan said the North Central CMA was aware of calls for recreation water to be put in the lake.
“To increase water levels for recreation, an outside source of water would need to be identified. Purchasing enough water to increase water levels at Lake Meran would be extremely expensive and depend on whether there is enough water available to be purchased from other water users,” he said.
“At the moment, water for the environment means people can swim, fish and bird watch. And when the lake is filled in 2021, providing there is water available, large boats and water skiing will again be popular.
“The health of the wetland will continue to be monitored over time and this top up of water for the environment is expected to be of benefit to tourism and recreation users also.”
The flows are authorised by the Victorian Environmental Water Holder in line with its Seasonal Watering Plan 2019-20, which is available for download from www.vewh.vic.gov.au, with regular watering updates posted on the North Central CMA website here.