By David Hendee / World-Herald staff writer

Jul 6, 2017 Updated Jul 6, 2017

NORTH PLATTE, Neb. — A pipeline that would pump water into the Platte River during dry years to help improve and maintain habitat for threatened or endangered species in central Nebraska is on track for completion in September.

The 10-mile pipeline south of North Platte is about two-thirds completed. It is advancing about 900 feet daily in 20-foot sections of pipe at a time.

The pipeline will tap underground water from a sprawling series of wells retired from crop production in a groundbreaking venture to avoid legal battles with other states and the federal government by providing water to the Republican and Platte Rivers. It is owned by the North Platte-based Twin Platte Natural Resources District.

Four natural resources districts in the region launched a river augmentation initiative in 2012 and named it the Nebraska Cooperative Republican Platte Enhancement project. It’s commonly known in the western Nebraska water world by its acronym, NCORPE.

The project’s goal is to ensure that Nebraska’s river flow obligations in the Republican and Platte Rivers are met by adding water that otherwise would have been used to irrigate corn and other crops on a sliver of the Sand Hills near North Platte in Lincoln County.

The pipeline south to the Republican, which flows across much of the southern tier of Nebraska before dipping into Kansas, has been operating for three seasons. Construction of the $8.2 million pipeline north to feed the Platte, which rises in the Rocky Mountains of Colorado and flows west to east across the length of Nebraska, started in March.

Kyle Shepherd of North Platte, the NCORPE project manager, said the North Pipeline has the capability of providing 7,700 acre-feet to the Platte annually. An acre-foot is the volume of water covering one acre of surface area to a depth of one foot. The pipeline starts with 42-inch-diameter sections and narrows to 36 inches. It will be ready for use next summer.

“It’s possible it won’t be needed for a year or two,’’ Shepherd said.

Unlike the Republican River, a prairie river, the Platte carries snowmelt from the mountains. During years of relatively high Platte flows — such as the past several — natural resources districts along the Platte try to capture excess water in canals, reservoirs and sandpits for release when it’s needed downstream.

“It’s not as reliable, obviously, but it’s a lot cheaper to capture that floodwater and be able to release it later than to pump pipeline water,’’ Shepherd said.

The North Pipeline will spill into the Nebraska Public Power District canal, which flows into Lake Maloney and past a State Game and Parks Commission fish hatchery before pouring into the South Platte River and eventually flowing into the Platte east of North Platte.

An eight-man crew from BRB Contractors of Topeka, Kansas, is burying the pipe in sandy soil under Miller School Road.

“It’s real tough, but we make it work,’’ said Dustin Pabolo of Kansas City, Kansas, the site foreman. “The soil just breaks apart too easy. It’s kind of dangerous.’’

Pabolo started using a steel shoring shield to protect workers in the pipeline trench soon after construction started, and the potential for a cave-in became evident.

The crew works in a tight area about the length of a football field. As one excavator operator digs a trench anywhere from five to 15 feet below the rolling surface, another fills in a trench containing a recently buried section of pipe. Positioned in a trench between the excavators, two workers set and align individual pipe sections. They repeat the process about every 20 minutes, setting from 40 to 50 sections of pipe daily. They typically work 10 days straight and then take four days off.

Similar to the Republican and its compact obligations, the Twin Platte NRD is under state and federal deadlines to increase flows in the Platte to 1997 conditions, in part to benefit threatened and endangered species. A water management plan requires the district to add water to the Platte, as needed, or area farmers could face extreme cutbacks in the amount of groundwater they would be permitted to pump to irrigate cropland.

 The augmentation project was inspired about five years ago by Nebraska Department of Natural Resources officials who suggested a bold scheme to help the state meet its water obligations: A sprawling irrigated farm southwest of North Platte was for sale. It had 115 groundwater wells, but the sandy soil was marginal cropland for nourishing corn, potatoes, soybeans and popcorn — and it was susceptible to wind erosion. The 19,500-acre Lincoln County property straddled the Platte and Republican River basins. Why not buy the farm, retire and restore the cropland to grassland and tap the aquifer with the farm’s 30 groundwater wells for augmenting flows in the rivers?

The two-river augmentation strategy was simple. By ceasing irrigation across nearly 16,000 acres on the Lincoln County farm, water that would have continued to be used for cropland would remain in the Ogallala Aquifer until needed to supplement flows in the Republican and Platte.

The Upper, Middle, Lower Republican and Twin Platte NRDs dove into the project. The roughly $110 million project is solely funded by an occupation tax on irrigated acres. No property taxes are used.

Shepherd said the volume of water pumped for the pipelines will likely be less than what would have been pumped had the property remained as an irrigated farm. Abundant groundwater lies under the NCORPE land. The saturated thickness of the Ogallala Aquifer in the area is about 400 to 600 feet.

Shepherd said the North Pipeline will protect the economic viability of the region by preventing a possible irrigation shutdown on 75,000 acres in the Twin Platte NRD with a market value of about $240 million. He said it also will prevent placing irrigators under strict water-pumping allocations and maintain local control of underground water.

Another benefit of the larger NCORPE project is that it is leading to the restoration of a corner of the Sand Hills as rangeland. It is the largest Sand Hills restoration effort in the state’s history.

david.hendee@owh.com, 402-444-1127