Wichita, Kan. -- An innovative pilot program just northwest of the city could lead to a full-scale replenishing of groundwater supplies that will help provide safe water for Wichita for years to come -- while aiding the environment at the same time.
The three-year test program is assessing the feasibility of using water from the Little Arkansas River to recharge the Equus Beds aquifer -- a major groundwater resource that has been used by the city of Wichita, several area cities, and local irrigators for more than 50 years. The water will only be taken from the river after it rains and the river has risen to a certain predetermined level.
"I appreciate the innovative efforts the city of Wichita is taking in regards to its future water supply," said David Pope, chief engineer for the Kansas Division of Water Resources. "The city is trying to meet its needs from locally available water supplies. I'm pleased that conservation is an important part of the plan."
The main goal of the pilot project is to recharge the aquifer to fill a 322,000 acre-foot void so the aquifer will be a consistent source of water for Wichita for many years to come. In addition, the recharged aquifer will create a barrier preventing below surface saltwater and oil field pollution from contaminating the aquifer.
The water used for recharge is extracted from the river using two different methods. Using above-base waterflow, an intake in the river is set to operate at a pre-determined water height above the base river flow. When the water level rises above the base level, the excess water is pumped to an infiltration site.
Secondly, the pilot project is using induced riverbank infiltration. When the river is high, water infiltrates into the river bank. A well is placed next to the river bank to pump this excess water.
The recovered water is then recharged into the Equus Beds aquifer using two different methods. The water is pumped to recharge basins or a recharge trench and then allowed to infiltrate through the soil. And secondly, the water is pumped directly back into the aquifer through a recharge well.
The surface water is treated after the water is taken from the river, but before it is pumped to the recharge site (a distance of several miles) with chlorine to keep biological growths from accumulating in the pipelines. Also, the water taken directly from the river is treated to remove suspended solids before being pumped to the recharge basins. A trace amount of triazine herbicides from agricultural runoff is also removed from river water using powdered activated carbon.
The project is part of the Bureau of Reclamation's High Plains Groundwater Recharge Demonstration Program. The project is partly funded by the bureau. Other agencies involved include the Environmental Protection Agency, Kansas Department of Wildlife and Parks, Kansas Department of Agriculture, Kansas Water Office, Kansas Department of Health and Environment, U.S. Geological Survey, U.S. Fish and Wildlife Service, and the Equus Beds Groundwater Management District No. 2.
The demonstration recharge project is required to prove the project's feasibility, develop design criteria, and show smallscale operation to state and federal agencies for approval and permitting. The full-scale groundwater recharge storage and recovery project will cost more than $100 million.
The project is a key component in Wichita's proposed Integrated Local Water Supply Plan, which will serve water demands through the year 2050. Other components include water conservation, greater surface water use from Cheney Reservoir, use of above-base flow from the Little Arkansas River, expanded groundwater supply from the local well field, restarting a reserve well field for blending groundwater with elevated salt concentrations during peaking periods, and continuous use of remediated groundwater.
In addition to the aquifer recharge project, other steps taken by the city have already saved 5.5 billion gallons of water in just three years. Conservation and more use of water from Cheney Reservoir are two other initiatives being taken by the city.
The plan is complex and Pope noted that a great deal of study is left to be done before it receives final approval.
Wichita city officials and water experts believe that recharging the aquifer is the greatest single initiative that can be taken to provide the city with groundwater into the next century. Therefore, the city continues to provide updates on the project to all water users in the area.
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