USGS Water-Year Summary 2023
50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR
LOCATION - Lat 18°25'51.49", long 66°31'36.69" referenced to North American Datum of 1927, Manati Municipio, PR, Hydrologic Unit 21010002, at bridge on Highway 2 and 2.3 mi (3.7 km) west of ManatÃ.
DRAINAGE AREA - 203 mi². (526 km2), approximately of which about 38 mi² (526 km2) is partly or entirely noncontributing, includes 6 mi² (15.5 km2) upstream from Lago El Guineo and Lago de Matrullas reservoirs which was previously excluded.
REVISIONS HISTORY -
WRD PR-86-1: 1970-71 (M), 1975, 1979, 1982-85 (P).
Code 8 "greater than" removed from 1996 peak on Feb. 6, 2020 because peak was computed from rating extension.
Drainage area revised in 2021 based on ArcHydro 2020, more detailed topo used.
SURFACE-WATER RECORDS
PERIOD OF RECORD - May 21, 1963 to November 1969; annual maximum discharge only. January 1, 1970 to current year.
GAGE - Water-stage recorder and satellite telemetry at station. Elevation of gage is 14 ft (4 m) above National Geodetic Vertical Datum (NGVD) of 1929, from topographic map. Prior to 1968 crest-stage gage at same site and datum 3.57 ft (1.09 m) lower.
EXTREMES OUTSIDE PERIOD OF RECORD - Approximate gage heights to gage datum of major floods, pointed out by local residents, are as follows: September 13, 1928, 36.6 ft (11.16 m), September 27, 1932, 36.3 ft (11.06 m), and August 4, 1945, 34.3 ft (10.45 m).
WATER-QUALITY RECORDS
PERIOD OF RECORD - May 21, 1969 to current year.