The drought in the Northeast entered its fifth year during 1966. By March, it was already the longest and most severe of record, and the federal Water Resources Council urged state and local officials in the twelve-state drought area to continue prudent planning. The water year (October through September) started with deficient streamflows from Virginia to Nova Scotia, and during the succeeding nine months the area of deficient flow had spread across much of the United States. Before rain in September alleviated the drought, the lowest flows of record were noted on several major streams, including the Potomac. The drought can be said to have continued through the water year in Massachusetts, Rhode Island, Connecticut, southeastern New York and Long Island, New Jersey, Pennsylvania, Maryland, and Delaware. Contents of reservoirs were generally below normal and groundwater levels, while rising in October, were still below average.
The groundwater condition is particularly important because groundwater represents the largest store of water and provides the base flow for streams. In dry years, more than 50 percent of the total flow of such streams as the Delaware, Susquehanna, and Potomac is supplied from groundwater, and during the growing season it may account for 75 percent of total flow. Only during severe drought is a deficit of ground water carried over from one growing season to another, but such a deficit was observed in the 1964-65 winter, and the 1966 growing season began with an even greater deficit. The end of October 1966 found the water table below normal in nearly all areas with the exception of Vermont and New Hampshire.
The New York City reservoir system, a focus of interest during the past two years, stood at 61 percent of capacity, just below "normal" for October and far above last year's 37 percent. As one result of the City's experience the Department of Water Supply, Gas, and Electricity reduced its estimate of reliable yield of the system by some 20 percent. Whether this is justified—i.e., whether our characterization of the regional hydrology has been mistaken or whether the drought is just a very unusual event occurring in an unchanged climatic system—is one of the profound questions raised by the drought. An overwhelming majority of public water supply facilities managed to meet all demands, but many communities had to utilize emergency supplies.
The Geological Survey has indicated that in its opinion the critical supply situation faced by more than a hundred Northeastern communities resulted not from an overall regional shortage but from a shortage of adequate storage and delivery facilities. This leads to the main issue: How much should be invested in water supply facilities? If the current drought is unlikely to recur for fifty or a hundred years, present standards of system reliability are probably adequate, and the best response may be just what has been done: belt-tightening and the short-term use of emergency supplies. If, on the other hand, there has been a permanent shift in climatic conditions which has carried the region into a downward trend of annual rainfall, then careful studies of what the drought conditions have cost the region must be made to determine the optimum amount of investment in new water supply facilities. Climatologists are currently debating this issue and their conclusions are far from unanimous.
A version of this article appeared in print in the January 1967 issue of Resources magazine.
