Pool level change

The public will get a chance to see four possible ideas at an upcoming open house to be held at Henry Horton Park (see related story).

Four of the ideas are considered "cornerstone" plans while others are either labeled backup plans or ideas that are "highly unlikely."

Doug Murphy, the head of the Duck River Agency, said there were originally 26 different plans and the current four concepts "have moved into a higher level of recommendation."

But, Murphy also said that the four "cornerstone" ideas are not the final plans and "are not set in stone"

"We could see variations of them, or we could go to the backup plans," Murphy said, but he said the ideas in their current form are slated for "detailed discussion".

However, Murphy emphasized that the current plans were "still a work in progress."

Eventually, a timeline will be established to meet the area's water demands over the next 50 years, he said.

Pool level change

One idea is to raise the winter and spring pool level at Normandy Reservoir by 5 feet to preserve water storage needs for the drier summer and fall months.

Estimated cost of such a project would be $15 million, which would include an allowance for the acquisition of 2,000 acres of flood-prone areas downstream from the reservoir.

This idea would satisfy the entire river deficit of 32 million gallons a day that is projected for the year 2060, and would increase the storage supply by 5 billion gallons.

Detailed environmental studies of the flow alteration would be required, including consultation with U.S. Fish and Wildlife Services. There also could be a negative impact due to a higher frequency of flooding.

This alternative would need to be combined with a modified release of water from Normandy to satisfy part of the projected deficit for downstream users. This idea could also be implemented in multiple phases, according to a draft summary.

Earlier refill

This concept has been combined with a similar idea -- to start the refilling of the reservoir at the first of February instead of a month later in March in order to capture high flows of water prior to the dry weather conditions that begin in June.

Last month, TVA began spilling water from Normandy after heavy rainfall resulted in the reservoir measuring some 7 feet above winter pool and as of yesterday, TVA began withholding water to start the build up to summer pool levels.

Higher dam

Another idea for Normandy Reservoir would be to increase the height of the dam by 5 feet, along with raising the winter pool level by the same amount and keeping the summer pool at its current level of 875 feet.

The estimated cost of this alternative ranges from $15 to $30 million and would depend on the need to raise roads and bridges.

Releases of water from Normandy could be increased to meet the needs of both Shelbyville and Columbia but there could be potential impacts to boat ramps and campgrounds as a consequence.

One issue with this idea is the impact it could have on the Short Springs Natural Area outside of Tullahoma, as well as the loss of shoreline vegetation due to flooding. Detailed environmental studies would also be required if this plan was used.

Monsanto use

The use of Monsanto Lake outside of Columbia for water storage is another option being explored.

The idea is to purchase the lake, a 5-billion gallon offstream storage reservoir off Duck River, and upgrade the existing pumping station in Columbia, building a 10-mile, 42-inch pipeline from the reservoir to Columbia's water treatment plant.

The proposed idea would cost an estimated $45 million, which would include an allowance for $7 million of potential improvement to the dam and spillway that already exist there.

Direct ownership would maximize the control of the water supply, it would reduce the reliance on Normandy Lake for water downstream and having the new offstream reservoir would also provide recreational opportunities for the region.

New intake

Building an intake near Williamsport and pumping the water back to Columbia's treatment plant is another concept being examined.

The project would cost an estimated $56 million and would require an intake and pumping station at River Mile 108 near Williamsport and a 17-mile, 42-inch pipeline to the water treatment plant in Columbia.

The plan is considered droughtproof and reliable and would result in a minor reduction to downstream flows due to uses in Maury County and south Williamson County, as well as reducing the reliance on Normandy.