By Gerhard Schneibel

About 15,000 elements of Sandy Springs’ stormwater system will be visually inspected, rated and indexed in coming months.

The City Council voted Nov. 4 to award two contracts associated with a comprehensive study of the system, much of which was built under lax standards more than 40 years ago and may be failing. Other municipalities in suburban Atlanta face similar problems.

Council members have estimated that repairing the system could cost $500 million. City staffers said they expect that the $405,774 to be paid to Arcadis and the $403,777 to be paid to CH2MHill will produce insight into how much the repairs will cost.

Both companies are based in Denver. CH2MHill employees manage most aspects of the city.

The money will pay to study about 80 percent of the stormwater system, Assistant City Manager Steve Rapson said.

“We’re going to take this exact same contract and do a two-year option so we actually can expedite the remaining 20 percent,” he said. “We would be coming before (the council) asking to do everything, but we just don’t think we can physically get it all done in the months remaining” this fiscal year.

The city’s fiscal 2009 budget includes $1.5 million for all stormwater system expenses, including $881,000 for the study.

As part of the CH2MHill contract, David Chastant, an engineer working on city stormwater issues, and two field inspection officers will become full-time-equivalent employees.

Arcadis will conduct the study; CH2MHill will administer the project. Rapson said the arrangement keeps together a team familiar with the city’s stormwater system, saving some money “in addition to not ripping apart that fabric we have in stormwater management.”

Information about the system is limited to the point that it isn’t clear even where the drainage basins are throughout the city.

The system’s rusted pipes are subject to collapse, creating sinkholes and fallout. As of June, 80 fallout cases had been reported.

Chastant said engineers will make a priority of identifying the drainage basins, then “create a string network that will help us when we do our inventory.”

Employees will “physically locate them and connect them so that we have a connected network,” he said. “If we have any pollution or anything like that, we’ll be able to trace it.”

Dist. 6 Councilwoman Karen Meinzen McEnerny said Fulton County did an “exhaustive study” of the Nancy Creek, Long Island Creek and Marsh Creek watersheds, and she wanted to know whether that information could provide a head start and cut city costs in studying the stormwater system.

While the county didn’t address the condition of the pipes, its study “created a base map, which will help,” Chastant said.

Depending on the cost of repairs, the city could institute a stormwater utility fee. In Ros­well, residents pay $2.57 to $3.95 a month to repair and maintain the stormwater system.