Dam

The Prettyboy Dam, completed in 1933, created Prettyboy Reservoir. Gunpowder Falls, the river below the dam, has become an ideal spot to cool off, hike along the trails and get away from the city.

AUGUSTA, Maine -- It took more than 160 years, but then, fishermen are nothing if not patient.Next year, they'll finally see the dismantling of the Edwards Dam, built in 1837 where the Kennebec River flows through here. Anglers had long protested, even before the dam was erected, that the dam would block salmon, striped bass and other fish as they swam upstream to spawn."This is the end of the road for them," Pete Didisheim said as he gazed at the veritable wall of water coursing over the dam.The river's once abundant and diverse fish population plummeted after the dam was built.

ENVIRONMENTAL HISTORY DAM! WATER, POWER, POLITICS, AND PRESERVATION IN HETCH HETCHY AND YOSEMITE NATIONAL PARK By John Warfield Simpson. Pantheon. 384 pages. Yosemite National Park is a beautiful land of betrayal. The name of the valley, with its towering waterfalls in California's Sierra Nevada mountains, was taken from the Yosemite Indians, who were massacred and driven from their sacred home by the U.S. Army in 1851. Fifteen years later, Congress pledged to preserve Yosemite as the world's first national park.

Since Tropical Storm Agnes ended its working life abruptly in 1972, Union Dam has stood in the Patapsco River as a broken monument to a bygone industrial era, but it's also an obstacle to migrating fish, a swimming hazard and a potential threat to a large sewer pipe. Its remaining time can now probably be measured in months. Fueled by federal stimulus money, efforts of state and federal officials and river advocates are expected to be realized in the coming weeks with a demolition crew rumbling into Patapsco Valley State Park on the Baltimore-Howard County line to begin dismantling the 209-foot-long concrete hulk.

THE DEVASTATION to one of Maryland's finest natural trout breeding streams from the collapse of a sediment pond dam may eventually be overcome. The dam will be rebuilt, the Cecil County stream purged of muck, the gravelly bottom restored, the fishery restocked. But concerns linger over questionable decisions at the federally supervised site and the sluggish response to the December blowout of the 15-foot-high pond retaining wall. There are decidedly conflicting views of the problems. Principal blame is placed on the lack of sealing gaskets for the overflow pipe, which leaked and eventually undermined the dam and polluted the tributary.

The state Department of Natural Resources is ordering Anne Arundel County to repair a dam at a Pasadena park because the 63-year-old structure may not be able to handle flooding from a major storm.DNR officials yesterday said the Lake Waterford Park dam, which lies on the east side of the 11-acre lake in Pasadena, could collapse if the area is hit with a 10-year storm -- that is, a severe storm that hits, on average, once every 10 years.Harald Van Aller, geotechnical engineer for the Natural Resourcesdam safety division, said state inspectors responded to a complaint about erosion last November.

PORT DEPOSIT - As 1,200 gallons of water per second thundered over the Conowingo Dam, scores of shad at the bottom of the wall flashed back and forth in the roiling froth like greenish-blue torpedoes. The fish were blocked in their springtime pilgrimage up the Susquehanna River to spawn. But then they nosed into an underwater trap, and were suddenly hoisted in a steel box 100 feet into the air and poured to the other side of the dam. This $15 million fish elevator - the largest in North America, and one of only a handful in the world - is credited with helping to revive the shad, a species that played a mythical role in American Colonial history before being nearly wiped out. Given the elevator's success over the past 14 years, scientists are puzzled about why the number of shad hitching a ride has mysteriously fallen this spring.

The bill for completing extensive structural repairs to Wilde Lake Dam, to meet state safety standards, is going up. But no one's sure how much more than an early $520,000 estimate the project will cost."

GLEN ECHO -- Little Falls Dam on the Potomac River, built to help supply metropolitan Washington with drinking water, has kept American shad from reaching its prime spawning waters for 40 years.Yesterday, state and federal officials knocked a hole in the dam, ceremonially speaking.Bruce Babbitt, U.S. secretary of the interior, joined Gov. Parris N. Glendening, Democratic Sen. Paul S. Sarbanes, Republican Rep. Constance A. Morella and others to celebrate the beginning of work on a notch in the dam that will allow shad, striped bass, sturgeon and perch to reach their historic spawning grounds in the 10-mile stretch north of the dam.Work on the 1,400-foot dam, upstream from the District of Columbia, marks another step in a national campaign to remove obsolete dams that stand in the way of fish that live most of their lives in salt water but migrate up freshwater rivers to reproduce.

The top U.S. military commander in Iraq warned Prime Minister Nouri al-Maliki in May that the country's biggest dam, just up the Tigris River from the northern city of Mosul, is at risk of collapse, putting the city's 1.7 million people in danger of being inundated by a 65-foot flood wave. The letter from Army Gen. David H. Petraeus, co-signed by the U.S. ambassador to Iraq, is included in an audit to be published tomorrow. The report found that little or no progress has been made to shore up the Mosul Dam since the May warning, largely because a $27 million project funded by U.S. reconstruction money has been plagued by mismanagement and possible fraud.