Monitoring Groundwater During Dry Periods

Yearly fluctuations in groundwater levels are normal, but the end of summer in drier years can lead to concerns about reduced well yields.

Groundwater levels tend to be highest during March and April because of winter snowmelt and spring rainfall. The movement of rain and snowmelt into groundwater is known as groundwater recharge. Groundwater levels usually begin to fall in May and continue to decline during the summer.

Groundwater recharge is limited during late spring and summer because trees and other plants use the available water to grow. Natural groundwater levels usually reach their lowest point in late September or October. In late fall, after trees and plants have stopped growing and before snow begins to fall, groundwater levels may rise in response to rainfall and recharge. Groundwater recharge persists through the fall until cold temperatures produce snowfall and frozen soil that limit the ability of water to infiltrate into the ground. Groundwater levels during winter may be stable or fall slightly until spring snowmelt and rainstorms start the annual cycle again. Most problems with wells tend to occur in late summer or early fall when groundwater levels naturally reach their lowest levels.

The natural fluctuation of groundwater levels tends to be most pronounced in shallow wells. As a result, shallow wells are usually more susceptible to drought than deeper wells. Shallow, hand-dug wells, for example, are often the first wells to dry up during drought. Although deeper wells may be slower to suffer from drought conditions, they may also take longer to recover after a drought has occurred.

If you are concerned about dry conditions affecting your well, some changes in habits can help reduce your water use. Not watering lawns or washing cars, only doing full loads of laundry, and taking shorter showers can all add up to conserve water.

Some counties in PA are currently under a drought watch for some conditions. To help citizens monitor conditions, the U.S. Geological Survey (USGS) provides a simple website that compiles the various drought measurements (precipitation, surface water, groundwater, and the Palmer Drought Index) into one county-based graphic at the USGS website. The circular graphic in each county provides more information about the current status of drought indicators in that county.

For more information on managing your well during drought conditions, visit Managing your well during drought