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<br />0022J7
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<br />STREAMFLOW CONDITIONS DURING APRIL 1985
<br />
<br />Streamflow generally decreased seasonally in a band
<br />from the southern Great Lakes States and New Jersey
<br />southward to the Gulf of Mexico, with Florida the only
<br />exception. Monthly mean flows remained in the below-
<br />normal range in Rhode Island, Connecticut, New Jersey.
<br />Delaware, Maryland, Virginia, Kentucky, Tennessee, the
<br />Carolinas, and Georgia, and also in parts of New Bruns-
<br />wick, Massachusetts, New York, Pennsylvania, West
<br />Virginia, Florida, Alabama, Mississippi, Nebraska,
<br />Wyoming, and California. Monthly mean flows de,
<br />creased into the below-normal range in parts of Alaska,
<br />Wyoming, Nebraska. South Dakota, Minnesota, Iowa,
<br />Missouri, Tennessee, Louisiana, Mississippi, Alabama,
<br />Florida, New York, New England, New Brunswick, and
<br />Quebec. Record April low flows occurred at 15 index
<br />stations located in the area of below-normal flows (see
<br />table on facing page) and 19 of the 33 selected reservoirs
<br />jn the area reported below-average contents for the
<br />month. For example, both the monthly mean flow of
<br />6,640 cubic feet per second (cfs) and the daily mean
<br />flow of 4,180 cfs on April 30 for the Delaware River at
<br />Trenton, New Jersey, were the lowest for April in 73
<br />years of record. New York City's Delaware River basin
<br />reservoirs were at 62 percent of full capacity at the end
<br />of the month, a record April low , compared to a long-
<br />tenn average of 100 percent of capacity for April.
<br />Drought emergencies were declared in New Jersey (April
<br />17), eastern Pennsylvania (April 26), and New York City
<br />(April 26). About 21 million people were affected,
<br />In contrast, streamflow generally increased scasona~y
<br />in southern Canada, across the northern tier of States,
<br />and in Oregon, Nevada, Utah, Wyoming, Colorado, and
<br />Puerto Rico. Monthly mean flows remained in the
<br />above-normal range in Utah and parts of adjacent
<br />States, and also in parts of Texas, Oklahoma, Missouri,
<br />
<br />Iowa, South Dakota, Minnesota, Illinois. Indiana,
<br />Michigan, and Ontario. The monthly mean flow of
<br />21,340 cfs on the Colorado River at Cisco, Utah was in
<br />the above-normal range for the 24th consecutive month
<br />and the 2d highest for the month in 73 years of record.
<br />Flood stages, as designated by the Nationai Weather
<br />Service, were exceeded on many rivers and small streams
<br />during April in Idaho, the Dakotas, Minnesota, Wis,
<br />cans in , Michigan, Nebraska, Iowa, lIIinois, Indiana,
<br />Ohio, Tennessee, Kansas, Arkansas and adjacent States.
<br />and in New York and Maine. Rapid snowmelt caused
<br />floods with recurrence intervals equaling or exceeding
<br />100 years at 7 sites in Michigan's Upper Peninsula (map
<br />on page 10) on April 20-22. For example, the flow of
<br />the Peshekee River near Champion was 5,000 cfs on
<br />April 20, almost 1,400 cfs greater than the previous
<br />maximum (see table on page 10). No damage esti,
<br />mates were available for the sparsely populated area.
<br />Streamflow at 12 index stations in Wyoming, Colo-
<br />rado, and Utah averaged 236 percent of the long,term
<br />median flow with 10 of the 12 sites in the above-normal
<br />range. The Great Salt uke rose 0.35 foot to an eleva,
<br />tion of 4209.90 feet above mean sea level, the highest
<br />elevation in over 100 years and about 0.35 foot below
<br />the maximum elevation predicted for about June 1 by
<br />the National Weather Service. April precipitation at Salt
<br />Lake International Airport was below average, the first
<br />month of below-average precipitation since November
<br />1982,
<br />The combined flow of the three largest rivers in the
<br />lower 48 States - Mississippi, St. uwrence, and Colum,
<br />bia rivers - was 1,591,000 cfs during April, 7 per,
<br />cent lower than last month, and 12 percent above the
<br />long-term median. These three large river sys.tems ac-
<br />count for runoff from more than half the conterminous
<br />
<br />CONTENTS
<br />
<br />Streamflow during ApriJ 1985 (map). _ .
<br />Streamflow conditions during Apri11985
<br />Ground-water conditions during April 1985 . . . . . . .
<br />US:lble contents of selected reservoirs near e_nd of April 1985.
<br />Usable \:ontents ofselect\:d reservoirs and reservoir systems, March 1983 to ApriJ 1985 (graphs)
<br />Flow of large rivers during April 1985 . . . . . . . . . .
<br />Dissolved solids and water temperatures for April at downstream sites on six large rivers.
<br />Tolal precipitation. April 1985. .......
<br />naod data for selected sites in Michigan, April 1985. .
<br />Monthly mean discharge in key streams (graphs) . . .
<br />Explanation of data. . . . . . .
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