Minden Press-Herald

Oct 01st

Recharge lake efforts stalled

With the high temperatures and drought affecting local bodies of water and oil and gas companies drawing water for their operations, many people are looking for alternatives to help restore water supplies and stop depletion.

Lane Merritt of Cotton Valley has been working on a possible solution.

When local authorities met, Merritt voiced concerns on the possibility of a recharge lake for the Sparta Aquifer being placed in the borrow pits between Minden and Dixie Inn.

Since his concerns were raised, nothing else has been done toward making the lake a reality, but Merritt has been researching alternatives.

"I always prefer to offer an alternative other than just saying 'no'," Merritt said. "This approach I am taking may not fly, either; however, the more research I do the more it seems feasible."

Merritt is proposing Horizontal Directional Drilling (HDD) of high volume water wells in shallow, stream valley alluvial aquifers.

An alluvial aquifer is an area of water-bearing sand and gravel typically found near lakes, streams and rivers.

The water under the Dorcheat floodplain, Lake Bistineau and the Loggy Bayou may not be of drinking water quality, but may be a great source to allow high withdrawal rates for industrial applications such as fracturing Haynesville Shale wells.

According to Merritt, most major streams have an unconfined alluvial aquifer lying just beneath their floodplains. Unconfined aquifers are not trapped by layers of impermeable sediment or rock, such as the Sparta Aquifer. These types of aquifers are recharged by rain falling directly on the floodplain and not necessarily recharged by the stream.

"In simple terms, I believe this implies that if the stream is deep enough to cut into the top of the aquifer then the stream can recharge the alluvial aquifer during dry periods," said Merritt. "The top of the Dorcheat alluvial aquifer may be at or just below the surface of the floodplain, or 25 feet or so below the surface. The water in the shallow underground aquifer actually flows downhill just like the surface waters while a portion of that water surely finds its way to the Sparta when it outcrops in our area."

Merritt said he does not know how thick the aquifer is along Dorcheat.

"I think that it is a good tradeoff as you are primarily drawing water from a surface water source, which when compared to ground water sources (here the Sparta Aquifer), has much more water available and has a minimal effect on the surface water system," said Supervisory Hydrologist for the USGS in Ruston Ben McGee about alluvial aquifer withdrawals.

The major purpose for using a horizontal well is to increase reservoir contact and enhance the productivity of the well.

As technology has advanced, drilling techniques for installing horizontal wells that were previously restricted to the petroleum industry have found their way to the water industry.

Since the mid-1980s, HDD techniques have been used to install horizontal wells for environmental remediation of groundwater contamination.

In some geologic environments, the thickness of the aquifer may not be sufficient to supply the required amount of water to a system of vertical wells, even though the aquifer is connected to a nearby surface body of water.

With HDD, however, significant volumes of water can be obtained using well screens placed horizontally in the aquifer. These screens have historically been referred to as infiltration galleries.

"To produce raw water from under Lake Bistineau or along the side of Bayou Dorcheat seems viable, according to all my research which coincides with your information," Merritt told McGee. "I would think this would also serve to furnish raw water for the Haynesville Shale drilling program along and under Red River. And the water is pre-filtered and should not significantly impact the surface water source during periods of drought or the Sparta Aquifer."

According to Merritt, all underground recharge water typically flows toward its natural watershed, such as surface bodies of water or streams.

With the Red River and Dorcheat having their own watershed, they might have an underground water-saturated layer of the earth that could be tapped to provide usable water for public use.

While vertically-drilled water wells would not produce a substantial volume of water, a HDD well, like those drilled in the Haynesville Shale for its natural gas, could possibly produce enough water.

Merritt thinks HDD wells would relieve stress upon the Sparta and low-yield aquifers using approved groundwater sources, provide cheap, naturally filtered, high quality groundwater for industrial use and provide naturally filtered high-quality water.

He plans to present his findings to the Webster Parish Police Jury in the future.






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