South Hadley Tracer Study

Background

A USGS study of the dry brook aquifer system developed a hydrogeologic conceptual model of the aquifer system. Physical hydrologic data suggest that groundwater flows from the recharge area towards the CT River with a strong hydraulic connection between  observation wells and the river itself. A physical hydrogeologic model that solves the groundwater flow equation determined the steady-state contributing area of the aquifer at two sustained pumping rates. The lower sustained rate of 300 gpm produced 90% of water from local recharge vs. 10% from the Connecticut River, while the 914 gpm pumping rate produced 50% from both sources. Refining the contributing area of the aquifer is critical for making informed decisions regarding the sustainability and vulnerability of the sole-source drinking water supply for the town of South Hadley.
 

Purpose

 To refine the contributing area (water source) for the production well in the dry brook aquifer using geochemistry and environmental tracers. This work seeks to answer the following questions:

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• Does the geochemistry of the pumped water support a connection to the CT river? 

• What fraction of produced water is local recharge (i.e., Dry Brook Hill) vs. induced infiltration from the Connecticut River? 

• What can be concluded from this data regarding the size and residence time of water in the aquifer system?