Baltimore's water supply, built over a 50-year period of the 20th Century, remains an enginering wonder -- three major reservoirs backed up by a 38-mile pipeline from the Susquehanna River (see second item in today's column). Here, from the city's Department of Public Works, are some facts about the three main watersheds and dam operations:

Loch Raven Reservoir
Elevation above mean sea level 240 feet
Spillway length 288 feet
Total length 650 feet
Height of crest above stream bed 82 feet
Length of shore line at crest elevation 50 miles
Area of land owned 8,000 acres
Flooded area at crest elevation 2,400 acres
Initial storage capacity: 23 billion gallons
Water surface: 2,400 acres
Crest elevation: 240 feet above mean sea level
Area of watershed: 233 square miles
Built 1912 – 1914 (elevation 188 feet)
Crest raised 52 feet: 1921 – 1922 (elevation 240 feet)
Overflowed crest first time: May, 1923

Liberty Reservoir
Elevation above mean sea level 420 feet
Spillway length 480 feet
Total length 704 feet
Height of crest above stream bed 160 feet
Length of shore line at crest elevation 82 miles
Area of land owned 9,200 acres
Flooded area at crest elevation 3,100 acres
Initial storage capacity: 43 billion gallons
Crest elevation: 420 feet above mean sea level
Area of watershed: 164 square miles
Built: 1951 – 1954
Overflowed crest first time February 6, 1956

Prettyboy Reservoir
Elevation above mean sea level 520 feet
Spillway length 274 feet
Total length 845 feet
Height of crest above stream bed 130 feet
Length of shore line at crest elevation 46 miles
Area of land owned 7,380 acres
Flooded area at crest elevation 1,500 acres
Initial storage capacity: 20 billion gallons
Crest elevation: 520 feet above mean sea level
Area of watershed: 80 square miles
Construction completed: 1933
Overflowed crest first time September 23, 1933