Wednesday, June 21, 2006
2006
A consultant's report says the sewer system's main problem is water that leaks in during storms.
Blacksburg's sewer system is just fine for now and well into the future. As long as it doesn't rain.
"Your system works great during dry weather," consultant Tim Wagner told the town council Tuesday afternoon. "Growth is not going to bother you if it doesn't rain."
Blacksburg's sewer capacity has been a recurring issue in recent years. It was cited as one justification for the controversial, ultimately defeated Toms Creek sewer proposal, and has been invoked to limit development plans.
Wagner is the project manager of a two-tiered study of the sewer system. He and his team reported the findings from the project's first phase at a council work session.
Overall, the system works well. But during a severe storm -- one the area should expect every 10 years or so -- more than 90 percent of what flows through some sewer pipes is coming from "inflow and infiltration." That's water that leaks into the system.
Wagner's team considered only those parts of town that already have sewers. The consultants evaluated the present capacity; what effect five years' growth would have; the effect of filling all the town's empty lots under current zoning; and the effect of filling those lots according to the comprehensive plan.
The town's sewers carry between 5.5 million and 6 million gallons a day now. The consultants' computer model showed five years of growth would increase that by 500,000 gallons a day. Both of the build-out options would increase the flow by about 1.5 million gallons -- but in different parts of town. Sewers would handle the increase better if growth follows the comprehensive plan, the consultants found.
More and bigger problems surface during wet weather.
"Everybody has wet weather issues," Wagner told the council. "Everybody has overflows during wet weather."
The question is where those overflows will come and how severe they will be. Not surprisingly, the oldest sections of the system have the most problems.
The second phase of the study will look at combatting those problems. It will take a series of projects over 10 or 20 years to correct the problems, he said.
In some places, pipes may have to be replaced or moved. At least one section lies under the edge of a creek. In other places, relining pipes or repairing manholes will help.
But nothing will stop inflow completely, Wagner said -- at least nothing affordable.
Now that town leaders know where the problems are, they can prioritize them.
"I think this is good base information," Town Manager Marc Verniel said, "which is something we haven't had in the past."
The study's next phase, Verniel said, will "help us identify where we can get the most bang for our buck."
