Griffith University have indicated groundwater as a significant source of saline inflow. Although impossible to measure the extent or even the concentration of any groundwater, ongoing in-lake measurements clearly indicate substantial inflows of salt from the canal having an impact. See diagram.
At the recent meeting with Council, the Care Group requested investigation into all inputs into the lake and to clarify the readings that indicate this salt input. Regardless of where the salt is coming from, the increasing trend in salt means more salt is entering the lake than exiting. Reducing a major input of salt from the canal has the potential to reduce the overall salt content of the lake and reduce stratification and lake decline.
The Griffith report 3 years ago highlighted the need for further information stating;
“More information on inflows is needed, both in terms of nutrient concentrations and volumes of water input from the storm water drains, as well as exchange of groundwater and/or the adjacent canal. An understanding of the source of the higher salinity water accumulating in the lake bottom is needed.”
Unfortunately 3 years on, Council has not taken steps to investigate and provide the necessary information/monitoring to determine the detrimental effects from the canal.
The key questions are;
- How can Griffith make a determination of significant groundwater without even assessing input from the canal in both tidal and rain events?
- Are Council planning to effectively monitor salt, flow and nutrients from the canal to assist in this determination?
The Care Group will advise on the reply once received.