Posted on March 1, 2018
By Raney Rapp, Farmtalk
Water and natural resource professionals from across the state met in Fredonia, Kansas to discuss the state of the Verdigris river area, including the four federal reservoirs at Fall River, Elk City, Big Hill and Toronto. The Kansas Water Office, U.S. Army Corps of Engineers, U.S. Department of Agriculture’s Natural Resources Conservation Service and Kansas Department of Agriculture came together to discuss water storage projections, infrastructure and water management for the Verdigris region.
Fall River
“Overall southeast Kansas is sort of declining in population and declining in demand,” said Nathan Westrup, water resource planner for KWO. “We ran the projected water requirements through a modeling program and determined how much storage we needed to meet our current and future demands at our current capacity.”
At Fall River, the modeling program showed sufficient storage for the reservoir to continue meeting its residential and commercial demands through a drought of record, Westrup said.
However, leading up to the year 2050, Fall River was predicted to use some of its inactive storage, or storage below 940 feet elevation. Westrup said storage usage is something they will keep their eye on as sedimentation in the lake increases.
Kansas Area Manager for the Tulsa District of the Army Corps of Engineers Eugene Goff said the Corps’ findings indicated the past repairs to the dam at Fall River Reservoir had held up well. Large debris had also been removed from the gates of the dam after heavy spring rains brought down fallen tree trunks and other rubble.
“We had a lot of big, old timber that had died and moved up toward the dam so we just removed that at Fall River and Toronto,” Goff said. “That was a massive undertaking that they did — it almost looked like it had rained logs and stumps down on that reservoir.”
Toronto
While the Toronto reservoir is no longer challenged to meet the demands of corporate water uses, it still contributes water to the lower stream and river systems, as well as being vital to protecting farmers downstream from floodwaters.
“Toronto is exclusively used to meet a target flow at Altoona that varies between 3 and 5 cubic feet per second,” Westrup said. “There’s no industrial or municipal water supplier that needs water from Toronto.”
Tornto is in great condition from a storage availability standpoint and from a structural standpoint as assessed by the Army Corps of Engineers. Goff said their assessment of the dam’s infrastructure read “unremarkable,” which he said is an extremely good sign.
“Toronto cost a little over $13 million to build back in the ‘60s where El Dorado dam built around 1983 cost around $75 million,” Goff said. “The neat thing about Toronto is that the benefit for downstream at Toronto is around $540 million worth of damages prevented downstream.”
Goff said the damages included in their assessment would be farmers being able to continue their crops without flooding or the preservation of pastureland for ranchers.
Big Hill
Big Hill Lake is one of the least-used lakes in the Verdigris system for meeting the needs of commercial and municipal water users. However, it does provide an excellent source of additional storage for the entire water system.
“We have 35 percent of conservation storage dedicated to our water marketing program,” Westrup said. “Based on our current capacity and yield we really only need 27 percent, so we definitely have sufficient storage.”
Westrup said in the future KWO might seek out additional customers for Big Hill Lake as it can handle more users without endangering the water levels of the reservoir.
Elk City
“Elk City is pretty heavily used for our biggest demand in the system,” Westrup said. “At Fredonia, we have a stream flow target of 5 CFS; at Altoona, we have a target at 3 to 5 CFS per month; and then for Independence in the Elk City system, we previously had a target flow of 20 CFS that has been raised to 35 CFS.”
The higher targets make it more difficult for the Elk City Reservoir to meet its target demands through the year 2025, Westrup said. Sedimentation, as well as higher targets, makes the future projection look dimmer than the other reservoirs in the Verdigris system.
“The sedimentation rate at Elk City is around 378 acre feet per year lost due to sedimentation,” Westrup said. “In our 2015 projections, we show enough loss from sedimentation that current operations will have insufficient water supply storage to meet demands within the target model.”
Westrup said a return to lower targets could easily help maintain water storage and capacity to meet demands in the current system, and he is optimistic for the future.
Source: Farmtalk
