Title: Applying the Watertable Fluctuation Method to Understand Groundwater Recharge Dynamics
Abstract:The water-table fluctuation method is a simple technique for assessing recharge to shallow unconfined aquifers using commonly collected groundwater level and rainfall data. The approach was applied to...The water-table fluctuation method is a simple technique for assessing recharge to shallow unconfined aquifers using commonly collected groundwater level and rainfall data. The approach was applied to the basalt aquifer of the Alstonville Plateau, on the north coast of New South Wales. The daily rainfall data was aggregated on an event basis, where an event is a consecutive sequence of rainy days. Different approaches were taken to derive the water-table rise for each rainfall event from the hourly groundwater level data. Using the difference between the daily groundwater level maximum and minimum gave the best fit with water-table rises measured graphically. Quantifying recharge relies on a reasonable estimate of aquifer specific yield, which is problematic considering the paucity of relevant data such as pump tests. Simple approaches, such as the rainfall-water-table relationship, chloride mass balance or base flow analysis gave inconsistent specific yield estimates. Regardless of limitations placed on quantifying recharge, the water-table fluctuation method is still useful in deriving an understanding of recharge dynamics. The relationship between the relative proportion of recharge to the magnitude of the rainfall event could be defined. Such analysis for the Alstonville Plateau shows that the large (>160mm) but sporadic rainfall events drives recharge to the shallow aquifer. In contrast, limited recharge was derived from the small (<20mm) but frequent rainfall events.Read More
Publication Year: 2008
Publication Date: 2008-01-01
Language: en
Type: article
Access and Citation
Cited By Count: 2
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot