Construction being done in the Fort Caspar neighborhood during the July 3 storms prevented run-off from reaching catch basins, flooding basements that otherwise wouldn't have been affected.

Federally-mandated protocols are meant to prevent construction debris, dirt and sand from washing into the North Platte River and its tributaries. Following the rules by blocking off drainage near construction sites hindered proper drainage of water from the storm.

"We have the area in the middle of construction, and one of the protections to protect water quality is to not have silt washing into sewers," Public Services Director Gary Clough said. "It's a good thing, but when we have a torrential downpour, it restricts our ability to get water into catch basins."

The city is paying for backflow preventers for residents with the caveat that they pay for the installation and maintenance of the device. The preventers would be installed on existing sewer lines and prevent the muck from rising through the pipes and into homes, Clough said.

The added pressure in the lines would force the sewage to either move faster down the line or rise to an area without a back-flow preventer.

"If there's enough backwash and flow, it could potentially flow out of manhole lids, but at that point in time, at least it's not causing damage to the houses," Clough said.

Between 45 and 48 homes could have been affected, he said, and the devices cost between $100 and $150 each.

"It's just being done as a good will gesture - that we're offering to purchase and provide [back-flow preventers]," Clough said.

Reach city reporter Pete Nickeas at pete.nickeas@trib.com or (307) 266-0639. Read more about Casper politics and government at http://tribtown.trib.com/redtape.