Salt water is gradually invading important freshwater streams and rivers, affecting water supplies and potentially the health of those on salt-restricted diets. United States Geological Survey scientists tracking the abnormal encroachment of saltwater have discovered the increases in salinity are creating several unusual environmental problems. Local officials are using USGS data to inform and protect citizens in areas of concern. Salt intake causes the human body to retain water, making the heart work harder and increasing blood pressure. Increased salinity in drinking water can pose a serious health hazard for people on salt-restricted diets.
Salt water can also corrode underwater equipment and cause freshwater organisms to move or die off.
One farmer who irrigates his crops with fresh water from a tidal stream in central Delaware couldn't understand why corn, irrigated with what is usually fresh water from that stream, was wilting. The USGS found the salt content in the stream had climbed as high as 5,000 parts per million, one half that of ocean water. Del. A slow moving salt front on the Hudson River is threatening water supplies in Poughkeepsie, N.Y., a city of about 30,000 located 75 miles north of New York City. Right now, it's standing still and water which is being pumped into the Hudson from area reservoirs is keeping the salt front at bay. But, Freeman said, only rain would clear the threat if the salt front begins moving upstream again.