A citizen scientist group in Jeparit has analysed more than a quarter-century of Wimmera River water samples to provide insight into the catchment's development.
The Jeparit Water Watch group is a volunteer organisation that collects and tests water samples from various locations along the Wimmera River and publishes the data in monthly reports.
The group published a report which compares the salinity levels of the Wimmera River samples from the last four years to those from 1996 to 1999 before the millennium drought affected water quality.
Jeparit Water Watch member Jeanie Clark said the findings show more stable salinity levels in the post-drought river than before the drought.
"It was only when I started comparing the readings from previous years that I saw a definite pattern emerging in the last four years. Then I went back and thought I would look at the same amount of time before the drought started impacting our readings," she said.
"So the two graphs show what the last four years have been like compared to the four years before the millennium drought.
"What I found is that it (water salinity levels) has become much more regulated, there is less variation than what there was in the late 90s."
Salinity readings have always been critical to Jeparit Water Watch as an essential indicator of river health.
Ms Clark worked as a Wimmera Community Water Watch coordinator from 1995 to 2009, was a founding member of Jeparit Water Watch in 1996, and provided professional support to the group through the Catchment Management Authority.
A decade since the role ceased, Ms Clark has been an active member of Jeparit Water Watch and compiles annual reports based on the group's water sampling.
Graphs compiled from the 2018-2021 samples show less variability than the 1996-1999 samples.
Ms Clark said there could be a couple of reasons for this.
"My assumption is that it is because we now have small environmental flows being put down the river," she said.
"So it can be seen that in the late 1990s, there were two rain events that flowed through Jeparit and a discernible pattern of higher summer and autumn salinities.
"In the most recent years, these ups and downs of the river's salinities are much more pronounced, but there was no rain event that flowed to Jeparit. The neater pattern is largely due to the advent of environmental flows,"
Ms Clark also said the construction of dams in the Pyrenees catchment area might have a role to play in the amount of environmental water flowing to the Jeparit area.
"The other factor to take into account is that in the 90s it was just beginning the buildment of catchment dams in the Pyrenees," she said.
"So before that, when it rained up in the Pyrenees, it would flow through to Jeparit, whereas now it doesn't - it gets caught in the catchment dam.
"That helped make it become a much more defined pattern than when we started the records."
Octogenarian water monitor Frank Pitt has been collecting samples from Lake Hindmarsh and the Wimmera River for Jeparit Water Watch since 2002.
He said he recalled when the lake and river had clear water, abundant fish and birdlife.
Mr Pitt hopes Jeparit Water Watch's data will help instil in others the urgent need to protect the waterways.
The complete data from Jeparit Water Watch can be seen at http://www.vic.waterwatch.org.au/.
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