RWBJV partners (Central Nebraska Public Power and Irrigation District [CNPPID], Ducks Unlimited [DU], Nebraska Department of Natural Resources [NDNR], Tri-Basin Natural Resources District [TBNRD], and U.S. Fish and Wildlife Service Rainwater Basin Wetland Management District [USFWS RWB WMD]) have completed multiple project elements associated with Phase I of the Western Basin Recharge Project. In Phase I high capacity infrastructure was installed from the CNPPID canal network to facilitate surface water deliveries to Cottonwood, Funk, Johnson, Linder, and Victor Lakes Waterfowl Production Areas (WPAs). Infrastructure ranged from a 36” delivery pipeline into Funk to an 18 inch delivery line into Linder. This infrastructure was designed to fill these wetlands with 3,000 acre/ft. of water in a seven day period. This will essentially allow these sites to go from dry to ponding at maximum capacity levels that will not adversely impact adjacent landowners in one week.
In addition to the water delivery infrastructure, water monitoring equipment was installed to allow the partners to quantify recharge rates through these wetlands. A hydrologist was contracted by the RWBJV to complete this monitoring. The monitoring was done using a Soil Plant Air Water modeling framework. This framework suggests that an acre of playa can recharge over 1.4 million gallons a day to the underlying aquifer. These observations were substantiated based groundwater monitoring wells that showed a five foot increase in groundwater levels around these wetlands. This level of recharge was significantly more than initially anticipated. Based on a 10% ponding frequency (36.5 days/year) an acre of wetland could recharge sufficient water to provide drinking water for 265 residents based on the average municipal water use (11,000 gallons/resident) or sufficient water to irrigate 3.5 acres with nine inches during the growing season. Staff from TRNRD and USFWS are working together to complete maintenance of this equipment. This is a tremendous contribution especially when it involves getting a 10 ft. latter into the middle of a basin with 18 inches of water. The next phase of this monitoring project will begin to quantify in-stream flow contributions from these wetlands to the Platte and Republican Rivers.
The next phase of the project involved restoration of the wetlands at these WPAs. In this phase, restoration has been completed at Cottonwood, Johnson, and Victor Lakes WPAs. The Cottonwood restoration is one of the largest restoration projects completed on public lands. This project included excavation 87,000 cubic yards of sediment from within the hydric soils footprint. In addition to the sediment removal, grazing infrastructure, tree removal, and reseeding is currently underway. The Cottonwood WPA restoration would have been possible without the acquisition of the Dahlgren tract. This acquisition was facilitated by DU and the RWB WMD. Additional restoration is currently underway at Linder and in the Funk White-front Unit. The Linder WPA restoration is slated to move 42,500 cubic yards of material out of the hydric soil footprint and re-contour a waterway coming into the wetland. As part of the Funk Whitefront Unit restoration, 110,000 cubic yards of material are being moved out of the hydric soil footprint with some additional waterway work to facilitate supplemental water deliveries to this unit.
Planning is underway to evaluate restoration potential in the Peterson Unit at Funk WPA. Initial evaluation of the topographic survey suggest a deposit of fill material in the hydric soil footprint. To evaluate conditions Natural Resources Conservation Service (NRCS) Soil Scientists will be on-site to complete a full soil survey. Based on the other restorations it is anticipated that a significant amount of material will also need to be removed from this unit.
To date, the engineering, soils investigation, monitoring, water delivery infrastructure, wetland restoration and enhancement activities have cost over $800,000. Thanks to all of the partners that have made this project a tremendous success.