USGS Water-Year Summary 2024

50059000 LAGO LOIZA AT DAMSITE NEAR TRUJILLO ALTO, PR

LOCATION - Lat 18°19'47.66", long 66°01'00.01" referenced to North American Datum of 1927, Trujillo Alto Municipio, PR, Hydrologic Unit 21010005, at pumpsite at damsite and 1.9 mi (3.1 km) south of Trujillo Alto plaza.

DRAINAGE AREA - 208 mi². (539 km2).

REVISIONS HISTORY - Datum of gage was previously reported in the site file as 135 ft (41.1 m) above NGVD29 and LMSL-Old PR. NGVD29 datum does not exist in Puerto Rico and the correct LMSL-Old PR elevation is 75 ft (22.9 m), published historical records did not reflect this site file typo. Revised to PRVD02 Datum in October 2022.

SURFACE-WATER RECORDS

PERIOD OF RECORD - December 1987 to current year.

GAGE - Water-stage recorder, satellite and radio telemetry at station. Datum of gage is above Local Mean Sea Level (LMSL- Old PR) and above Puerto Rico Vertical Datum of 2002 (PRVD02).

REMARKS - The reservoir is formed by the Loíza Dam, a concrete structure completed in 1954. Usable capacity of impoundment is 30,000 acre-ft (37 hm3). Out flow from lake is controlled by five slide gates in power plant and pump intake structure, four sluicegates, and concrete spillway with eight radial gates. Lake is used for municipal water supply and intermittent power generation. New capacity table based on US Geological Survey Water-Resources Investigations Report 99-4143, 1996. Prior to October 1994, published as Lago Loíza at Damsite.

EXTREMES FOR PERIOD OF RECORD - Maximum elevation 147.42 ft (44.93 m), September 18, 1989; minimum elevation, 108.52 ft (33.08 m), July 18, 1994.

WATER-QUALITY RECORDS

PERIOD OF RECORD - Water years 1974 to September 2012, discontinued.