Groundwater resources management by aquifer storage and recovery : a case study of regional municipality of Waterloo, Ontario, Canada

Abstract EN

The Regional Municipality of Waterloo (RMOW) relies mainly on local groundwater resources for its drinking water supply.

The Region covers an area of approximately 1,230 km2 including the cities of Cambridge, Kitchener, and Waterloo, as well as rural areas comprising the Townships of Woolwich, Wilmot, Wellesley, and North Dumfries.

RMOW is developing a strategy for the protection of the water resources to guarantee safe drinking water supply for present and future generations.

Aquifer Storage and Recovery (ASR) technique has been applied for management of groundwater resources at the Mannheim site.

Geology and hydrogeology of the Waterloo Moraine was reviewed with a particular emphasis on the depositional and hydrostratigraphy units.

Generally, the aquifer system of the Waterloo Moraine is a multi-layered aquifer system that consists of three overburden aquifers separated by four aquitards, with the upper portion of the bed rock aquifer classified as the fourth aquifer unit.

There are 126 municipal pumping wells, grouped into 50 well fields providing approximately 75 percent of the water supply needs of over 400,000 residents and associated industries.

The objective of this study was to evaluate the feasibility of implementing an Aquifer Storage and Recovery (ASR) system at the site of Mannheim and to confirm the preferred aquifer storage zones.

The available groundwater flow model previously developed for the site was revised to simulate the response of the aquifer during recharge, storage and recovery.

The actual measured total target storage volume of the operated wells was 1,363 ML with constant recharge and recovery rates over continuous time periods.

The simulated annual ASR cycle involved recharging 227 million liters (ML) per day in total into the five ASR wells continuously for 60 days, storage for 180 days, and recovery for 30 days followed by a natural recovery period of 95 days.

The model water balance showed that the site zone has been with apparent deficit of approximately 42 ML of water at the end of an annual ASR cycle, which represent about 3 percent of the recharge water volume and one percent of the total water which inflows to this zone.

This deficit of water may be due to the accuracy of input data and model calibration.