A slip of the tongue from Rivanna Water and Sewer Authority Chairman Mike Gaffney made for a pleasant start to Tuesday’s public meeting on a dredging feasibility study for the South Fork Rivanna Reservoir. Gaffney referred to engineering firm HDR’s "expensive—extensive—experience," then paused while a few audience members laughed.
In fact, it was the only real money talk of the evening. HDR will likely present cost estimates for a dredging project—not currently a component of the RWSA’s 50-year water supply plan—in May. Carey Burch, HDR’s project manager, told a crowd of residents and public officials from both city and county that "we haven’t identified any show-stoppers in terms of dredging the reservoir." The study estimated the reservoir’s water storage volume at a minimum 1,247 million gallons. The estimated dredging volume totals 1.54 million cubic yards of sediment.
How about show-starters? Burch and partner Peter Berrini shared the good news that 39 of 40 contaminants were not present in the reservoir water (and barium levels were lower than Virginia dranking water standards), and no metals were present at harmful levels. Berrini also shared a "wish list" for dewatering any sediment dredged from the reservoir: 60 to 100 acres of land, near the reservoir and contributed by a "willing landowner." Or, there’s always dewatering using geotextile tubes (see video below). Pick up next week’s C-VILLE for more.
A geotextile tube, used for trapping dredged sediment and releasing water. HDR’s Carey Burch described the tube as a "single-use product. It’s kind of like a sausage skin, if you will."
