ARWA Explains Interest In Sandy River Reservoir

Published 5:05 pm Thursday, February 7, 2013

FARMVILLE – Reacting to increased and severe drought impacts, the Appomattox River Water Authority (ARWA) is moving toward an offsite reservoir (OSR) to assure meeting its water supply responsibilities following a detailed analysis of future water needs and alternatives for meeting increased demand.

The request to Prince Edward County regarding the Sandy River Reservoir (see page one story) is key to the ARWA's desire to accurately predict the performance and reliability of the Sandy River Reservoir were that specific OSR alternative to be made available by Prince Edward County and pursued by the ARWA, which was created in the 1960s as a regional water supply for the cities of Colonial Heights and Petersburg, in addition to Chesterfield, Dinwiddie and Prince George counties.

“We're just in really planning level discussions with (Prince Edward County officials) and we just really have a verbal proposal,” ARWA Executive Director Robert C. Wichser told The Herald Thursday. “We haven't even written anything…yet. So we have to sit down and…if in fact we were granted the option (it) would be a technical study we would be looking at. It's much too early to really give any specifics but what will happen is we'll sit down, we'll take a look at that great site and we'll look at the potential, if it can provide any type of-during extreme drought conditions-could it provide, augment any type of water at all down this way.”

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Chesdin Reservoir has keenly felt the increased frequency of drought conditions that directly affect the reservoir's water level and an offsite reservoir would be used to supplement the flow of the Appomattox River, which feeds the Chesdin Reservoir.

In September of 2010, the water level in Chesdin Reservoir dropped nearly 12 feet below the level of the Brasfield Dam spillway-the water lowest level since the reservoir was filled 46 years ago. Furthermore, the water level has dropped more than four feet every year since 2007, with the exception of 2011, according to information on the ARWA website.

ARWA completed an Alternatives Analysis, performed by Black & Veatch, to study longer term supply needs and the options to increase raw water supply.

As a result, an offsite reservoir is preferred over raising the Chesdin Reservoir Dam or dredging Chesdin Reservoir, a 3,100-acre water supply reservoir.

In its Raw Water Supply Alternatives Analysis prepared for the ARWA by Black & Veatch, dated September 2012 and found on the ARWA website, the conclusion of the comprehensive 45-page study and analysis is that, “based on results of the criteria analysis model, an OSR is the apparent best solution for future raw water supply need. The water adequacy analysis performed by Black & Veatch determined that the current regional water supply was sufficient for approximately the next 50 years. However, there are other external drivers that warrant continued investigations on how to best supplement Lake Chesdin to reduce the frequency of drawdowns of the lake as have occurred over the last 10 years. As such Black & Veatch recommends further evaluations of an OSR alternative to confirm its viability as a future raw water supply.”

The conclusion continues, saying “based upon preliminary investigations performed by others, an OSR appears to be a viable option for water storage. To more accurately predict future performances of an OSR and the development costs associated, Black & Veatch recommends ARWA undertake the following studies and evaluations:

“The estimated hydraulic conductivity presented in our report was estimated through a desktop evaluation and did not rely on insitu permeability data. A site specific subsurface investigation and permeability analysis should be undertaken to improve confidence in the facilities permeability.

“A flow model should be developed to characterize an OSR and surrounding area. This model will provide a range of expected water fluctuations and resulting seepage.

“Determination and understanding of the water surface elevations and associated capacity is the baseline for the successful operation of the OSR,” the Black & Veatch study states.

Wichser described the Sandy River Reservoir as “a wonderful site. I actually visited it on Tuesday, went out to it and walked around it. It's a beautiful location, very nice…great for the citizens' recreation. We noticed there was one boat trailer so we assumed he was out bass fishing. We saw a lot of ducks in the water, so a very beautiful site.”

Wichser again cautioned, “it's too early, sit tight, what we would envision again is that your county administrator would coordinate any request and I'm sure that would be made public…”

Noting the climatic changes going on in Virginia, Wichser observed, “and when you look throughout Virginia, particularly the Piedmont region, and out toward Roanoke, and along (Interstate) 81, you look at the monitoring, the state has groundwater wells, and you look at the impact of not getting rain and getting the wet weather events that we've gotten throughout the year, it's just not happening. And so that's impacting everyone, not only surface water users but also groundwater users.”

Addressing what would occur if Prince Edward County granted the ARWA permission, Wichser said, “it would a technical study. Because, again, you have to determine, if there was any release of water, you're going to lose water to evaporation and during droughts you're going to lose water to streambed absorption, so there have never been technical studies done what a release would do for this reservoir down here. That's what we're looking at.”