Aquifer Recharge

The Drew Forest Preserve provides critical recharge for the Buried Valley Aquifer, a major source of drinking water for 31 municipalities in Morris, Essex, Somerset, and Union County. It provides all of the drinking water for the Madison, Chatham Borough, Florham Park and East Hanover.

Through its canopy and roots, the Forest captures and purifies approximately 71.5 million gallons of rainfall each year (based on 48” average). According to a 2007 report by the NJDEP, the value of this ecosystem service is $19,803 per acre (today’s dollars: $28,912). Multiplied by 53 acres, the value is $1,532,336 per year.

The Forest is right in the heart of the Buried Valley Aquifer, a large expanse of sand and gravel that sits on top of buried glacial valleys. Aquifer recharge happens slowly as water must seep to deep depths. But in the process it is cleansed naturally.

The towns that are most important for Buried Valley Aquifer recharge (towns whose borders are entirely within recharge zone) are all in Morris County: East Hanover, Florham Park, Hanover, Long Hill, Madison, Morristown and Morris Plains. Chatham Borough is located partially in the recharge area but relies on the aquifer for all its water.

As can be seen in the Geological Survey map in the images below, rates of recharge (inches per year) vary from zero in some areas, to 15-19” in much of Madison, to the highest level of 25-32” in the Drew Forest and Giralda Farms.

Maintaining and protecting aquifer recharge to the Buried Valley Aquifer is critically important given that water levels are decreasing over time as water use has increased and recharge areas have been developed.

Read more: NORTH JERSEY GREEN: Drinking water, forests and answers beneath your feet