Hard hats and helium balloons marked the occasion as politicians and Army officials gathered in Dell Canyon Monday to officially launch the $51.3 million Little Dell Dam project.

Planned for more than half a century, the 224-foot-high dam will provide flood control for Salt Lake County's 13th South flood plain and drinking water for an additional 30,000 residents.The guest list for today's ceremonies included Sen. Jake Garn, Rep. Wayne Owens, Lt. Gov. Val Oveson, Assistant Army Secretary Robert W. Page, Brig. Gen. John F. Sobke, Lt. Col. Robert A. Bauman, Salt Lake Mayor Palmer DePaulis and Salt Lake County Commissioner Dave Watson.

Charles W. Wilson, chairman of the Metropolitan Water District and one of the dam's earliest sponsors, launched the project by releasing a helium-filled balloon.

The project is a joint venture of the Army Corps of Engineers, Salt Lake County and the Metropolitan Water District of Salt Lake City, which provides long-term water development for the city's public utilities department.

The dam is scheduled to be completed in 1991 and will begin to fill in the spring of 1992, creating a lake 1.4 miles long. Located about seven miles above the mouth of Parley's Canyon, the new lake will be approximately a mile east of Mountain Dell reservoir and will supply some 7,920 acre-feet of municipal and industrial water annually.

Interlocal agreements authorizing construction of Little Dell were signed June 10, 1986.

Local sponsors will pay 42.5 percent of the project cost. The county will contribute up to $7.6 million through its flood control mill levy, while the water district will use revenue bonding on future water sales. The Utah Department of Water Resources also is subsidizing the Metropolitan Water District's interest costs with a $1.6 million grant.

Had there been a Little Dell in 1983, officials said, there would have been no need to build sandbag dikes when heavy runoff and precipitation flooded 13th South in Salt Lake City.

The dam also will provide nearly three times as much water as the older Mountain Dell, which holds approximately 3,200 acre-feet of culinary water, which is reserved for late summer.

Pipelines were built at the mouth of Parley's Canyon in 1987 to allow gravity-fed - rather than electrically pumped - water to supply storage tanks in the city water system from the University of Utah on the north to the mouth of Millcreek Canyon on the south.

Although deleted from the original concept, limited, non-motorized recreation could be developed at the new lake, officials said. An old pony express station located near the site has been protected from deterioration and could be restored when the project is completed.