POTOMAC RIVER BASIN
01639000 MONOCACY RIVER AT BRIDGEPORT, MD

Hydrograph

LOCATION.--Lat 39°40´43", long 77°14´06", Frederick County, Hydrologic Unit 02070009, on right bank 60 ft down-stream from bridge on State Highway 140 at Bridgeport, 0.9 mi upstream from Cattail Branch, 3.4 mi northwest of Taneytown, 4.8 mi downstream from confluence of Rock and Marsh Creeks at Pennsylvania-Maryland State line, and 52 mi upstream from mouth.

DRAINAGE AREA.--173 mi 2.

PERIOD OF RECORD.--May 1942 to current year.

REVISED RECORDS.--WSP 1382: 1944(M).

GAGE.--Water-stage recorder. Concrete control since Sept. 15, 1947. Datum of gage is 340.83 ft above sea level (levels by U.S. Army Corps of Engineers). Prior to May 3, 1946, nonrecording gage and crest-stage gages at site 0.3 mi downstream at datum 0.98 ft lower.

REMARKS.--Water-discharge records good except those for estimated daily discharges (ice effect), which are fair. Occasional regulation at low flow from unknown source upstream from station.

EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of Aug. 24, 1933, reached a stage of about 25 ft, present site and datum, from floodmarks, discharge, about 23,000 ft 3/s. Stage exceeded that of June 1889, from information by local residents.

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1942 - 1996, BY WATER YEAR (WY)

       OCT    NOV    DEC    JAN    FEB    MAR    APR    MAY    JUN    JUL    AUG    SEP

MEAN   90.7    179    267    300    379    456    302    213    137   84.8   61.4   85.8
MAX     906    513    697   1214   1029   1606   1029    964   1065    598    613   1027
(WY)   1977   1986   1984   1996   1961   1994   1983   1989   1972   1949   1942   1975
MIN    3.24   10.4   13.7   13.8   51.0   94.7   58.1   41.2   10.5   2.68   2.40   2.34
(WY)   1964   1954   1966   1981   1980   1949   1995   1969   1966   1966   1944   1943

SUMMARY STATISTICS WATER YEARS 1942 - 1996

 ANNUAL MEAN                          211
 HIGHEST ANNUAL MEAN                  447              1996
 LOWEST ANNUAL MEAN                    76.8            1954
 HIGHEST DAILY MEAN                 16700       Jun 22 1972
 LOWEST DAILY MEAN                       .00        (b)
 ANNUAL SEVEN-DAY MINIMUM                .04    Jul 22 1966
 INSTANTANEOUS PEAK FLOW         (c)24400       Jun 19 1996
 INSTANTANEOUS PEAK STAGE              25.42    Jun 19 1996
 INSTANTANEOUS LOW FLOW                  .00        (f)
 ANNUAL RUNOFF (CFSM)                   1.22
 ANNUAL RUNOFF (INCHES)                16.61
 10 PERCENT EXCEEDS                   447
 50 PERCENT EXCEEDS                    65
 90 PERCENT EXCEEDS                     8.3

a  Sept. 6, 7.
b  July 25-28, 1966.
c  From rating curve extended above 14,000 ft3/s on basis of slope-conveyance study.
d  Oct. 4, 5.
f  July 24-29, 1966
Excerpted from: James, R.W. , Helinsky, B.M., Simmons, R.H., and Tallman, A.J., 1996, Water Resources Data Maryland and Delaware Water Year 1996: U.S. Geological Survey, p.264-265.