Using elemental profiles in the sediment of a lake used to supply drinking water to understand the impacts of urban stormwater recharge

2013 ◽  
Vol 64 (6) ◽  
pp. 493 ◽  
Author(s):  
J. L. Vanderzalm ◽  
P. J. Dillon ◽  
G. J. Hancock ◽  
C. Leslie ◽  
J. Dighton ◽  
...  

The regional city of Mount Gambier, South Australia, recharges stormwater directly into the underlying unconfined, karstic Gambier Limestone aquifer. This aquifer provides the majority of recharge to Blue Lake, a groundwater-fed volcanic crater lake, used for Mount Gambier’s drinking water supply. However, concern remains regarding the risk posed by contaminants within stormwater, in particular when stormwater recharge may ultimately contribute to a source of drinking-water supply. The present research examined the role of the annual calcite precipitation in the lake, in protecting the quality of its water supply, by examining the composition of particulate matter in the lake and on the lake bottom. The sediment did not reveal negative impacts of stormwater recharge, but did highlight the increase in erosion as a result of settlement and extensive land clearing for agriculture at the time of settlement. Analysis of lake-floor sediment revealed increased accumulation of the lithogenic elements within the lake-floor sediment during this interval, owing to the cleansing capacity of the calcite precipitation cycle. Extraction of water from Blue Lake for water supply has resulted in a reduced water residence time in the lake and a three-fold increase in the accumulation of calcium carbonate on the lake floor.

1984 ◽  
Vol 119 (4) ◽  
pp. 473-486 ◽  
Author(s):  
MARGARET M. DORSCH ◽  
ROBERT K. R. SCRAGG ◽  
ANTHONY J. MCMICHAEL ◽  
PETER A. BAGHURST ◽  
KENNETH F. DYER

2011 ◽  
Vol 63 (4) ◽  
pp. 719-726 ◽  
Author(s):  
J. L. Vanderzalm ◽  
D. W. Page ◽  
P. J. Dillon

The Blue Lake is an important water resource for the city of Mount Gambier and the surrounding region, primarily as the drinking water supply source, but also as a tourist attraction. Mount Gambier’s stormwater is discharged directly via drainage wells into the unconfined, karstic Gambier Limestone aquifer, which in turn provides the majority of recharge to Blue Lake. Discharge of urban runoff to the aquifer commenced in the 1800s as a means of stormwater management, but is now recognised as contributing to the drinking water supply in Blue Lake. Recently, guidelines for managing the risks associated with water recycling and augmenting drinking water supplies have been developed. This paper examines the organic chemical hazards associated with a stormwater to potable recycling scheme as an example of the current risk management framework.


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