Drought conditions in Maine, 1999-2002: A historical perspective

Hydrologic drought can be defined as reduced streamflow, declining ground-water levels, and (or) reductions in lake or reservoir levels. Monthly precipitation totals, annual 7-day low-flow surface-water recurrence intervals, and month-end ground-water levels from drought years 1999-2002 show that 1999-2002 was the driest period of hydrologic drought in more than 50 years of record in Maine. Record lows were set in all three data sets at select locations in central Maine in April 1999, and in September 2001 and 2002. Although streamflows recovered to normal levels during 2000, ground-water levels in central Maine indicate that the drought carried over through 2000 into 2001 and 2002 in some locations.

In 2001, annual 7-day low flows with greater than 100-year recurrence intervals were recorded in central Maine and low flows with up to 75-year recurrence intervals were recorded in coastal areas. In 2002, annual 7-day low flows with greater than 100-year recurrence intervals were recorded at 4 of 14 stations analyzed statewide, placing it as the driest single year of hydrologic drought on record. Month-end ground-water levels at one location in central Maine indicate that the recent hydrologic drought years were the most severe in more than 50 years in that region. The period from 1947 to 1950 may have been the only comparable period of drought to the 1999-2002 period, in Maine. The 1960s drought, although extreme in the far northern and far southern regions of the State, was most exceptional for its duration from 1963 to 1969.