Virginia Ishler Livestock & Environment

The Chesapeake Bay watershed gets a lot of attention. However, there are other watersheds in Pennsylvania that are also important.

The six major watersheds, also known as basins, include the Ohio River, Susquehanna River, Delaware River, Potomac River, Lake Erie and Genesee River.

The streams funneling into these watersheds, large or small, contribute to the surface and ground water used by households, businesses, industries and farms.

We take for granted that water is a limitless resource, but the drought in California and major weather events across the country illustrate that water quality and quantity are delicate resources.

Pennsylvania is the sixth most populous state, home to nearly 13 million residents. This is coupled with a huge livestock industry.

According to the 2015 State Agricultural Overview compiled by USDA, there are 57,900 farm operations in the state on 7.7 million acres.

There are also several million cattle, poultry and hogs. Then there are the sheep, goats, horses and other livestock that rely on an ample water supply.

Groundwater is the main water source in rural parts of the state, with more than 1 million private wells providing water to about 3 million residents.

Of the 50 states, Pennsylvania has the second largest population using private wells for drinking water.

The annual precipitation for Pennsylvania averages 40 inches, but there can be a wide range depending on the geographic location.

Rainfall makes up most of the precipitation, but melted snow accounts for nearly 20 percent of the annual precipitation in some parts of the state.

About 7 inches of Pennsylvania’s annual precipitation enters streams directly as runoff, and about 13 inches in the form of recharge — precipitation that infiltrates the soil surface and becomes the groundwater that feeds springs, streams and wells.

Groundwater recharge occurs mostly in the spring and fall when plants are not consuming precipitation. Serious water supply problems can occur when rainfall and melting snow are lacking during the spring and fall.

The concerns related to the Chesapeake Bay watershed should not be underrated, but there are significant threats to our water supply other than nitrogen, phosphorus and sediment contamination.

There are concerns about the local use of groundwater exceeding the amount of recharge that supplies the aquifers.

Groundwater supplies can be threatened by increasing impervious cover of the land surface such as sidewalks, driveways and parking lots that minimize recharge capabilities.

Every acre of land that is covered with an impervious surface generates 27,000 gallons of surface runoff instead of groundwater recharge during a 1-inch rainstorm. This can result in water being removed more quickly than it can be recharged.

This has been most frequently documented in rapidly urbanizing parts of Pennsylvania, where impervious cover has increased rapidly and groundwater withdrawals have also increased.

The quality of groundwater is a concern in some areas of the state. Some pollutants occur naturally when water interacts with impurities in the rock layers encompassing an aquifer.

For example, hard water deposits from calcium and magnesium are common in groundwater from limestone aquifers, while hydrogen sulfide — which causes rotten-egg odors — iron and manganese often occur in certain sandstone and shale aquifers.

Corrosive water from acidic rocks can cause the lead and copper to dissolve from household plumbing, leading to toxic concentrations capable of causing serious health problems in humans.

The current situation in Flint, Michigan, brings to light what can happen when high lead levels get into the drinking water.

There are some simple steps to help minimize contamination of private wells or springs. Do not apply fertilizers, herbicides or other chemicals within 100 feet of wells or springs.

Test the water supply on an annual basis; divert runoff from roofs, sidewalks and driveways into rain gardens or yard areas where it can recharge groundwater rather than run off; and properly construct and maintain the on-lot septic system to prevent groundwater contamination.

More information on groundwater and watersheds can be found at

Virginia “Ginny” Ishler is a nutrient management specialist and manager of Penn State University’s dairy complex.


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