During April-May 2017, the NRD measured 528 observation wells throughout the District and then averaged the data of all these wells. Overall, the spring 2017 average measurement for the groundwater level change shows a decline of 0.53 feet from last spring. The findings show that the spring 2017 average groundwater level is 3.02 feet above the “Allocation Trigger.” As a result, there will be no allocation restrictions for the 2018 irrigation season.
All groundwater irrigators are required to annually report their water use. This is how the NRD records historic use. Irrigator’s records are very important for making wise management decisions. Even though the reported 2016
withdrawals were above the three-year average, they were still well below the 2012 growing season usage. That is good news for landowners, operators, and District staff as the 2016 growing season was certainly one for the record books. Heavy spring rains (avg. 10.21” in April and May) and above average temperatures in June (eight degrees warmer than June 2015) made for a non-typical growing season in the Upper Big Blue NRD. As the 2016 growing season and harvest went by, the NRD had some producers reporting that they were using as much water in 2016 as they did in 2012. Hence, the amount of water pumped during the 2016 growing season has a direct impact on the groundwater level measurements collected during spring 2017.
The District goal is to hold the average groundwater level at, or above the 1978 level. In 2005, the District average groundwater level reached the “Reporting Trigger” initiating groundwater users to report annual groundwater use to the District and to certify their irrigated acres. If the District average level falls below the 1978 level (“Allocation Trigger”), groundwater allocation will begin.
Observation wells are measured in the spring of each year, allowing the water table to rebound from the previous irrigation season. The observation wells measured are uniformly distributed and represented geographically throughout the District to provide an accurate profile of the District average. Each well measured is assigned an area of the District based on distances to other measured wells. This method of averaging is called the Thiessen polygon method, and gives the average groundwater level change calculation a weighted average. For more information, please visit www.upperbigblue.org or call (402) 362-6601.