CPNRD’s Groundwater Quality Management Program is having a beneficial impact on the nitrate levels in groundwater. Producers have been instrumental in the success of the program by implementing best management practices and newer, more efficient technologies as they are developed. The program, which has been in effect since 1987, is undertaking a long-term solution for the District’s widespread high groundwater nitrate-nitrogen problems. Nitrate-nitrogen levels have been lowered through management efforts primarily by landowners. Current average nitrate levels throughout the District are 13.3 parts per million (ppm); down from 19.24 ppm when the Program was implemented.
MAPS of each Phase Area are available at: http://cpnrd.gisworkshop.com Click “Yes” on the Disclaimer. Locate “Layers” at the top right of the page and select which map you’d like. To print maps, locate “Tools” on the top left and click the print icon.
VADOSE ZONE NITRATE STUDY PDF
June 1, 2017 – Dr. Dan Snow, director of Water Sciences Laboratory, UNL, gave a progress report on the Central Platte Natural Resources District (CPNRD) Vadose Zone Nitrate Study at CPNRD’s board of directors meeting on Thursday. Core samples were collected for vadose zone nitrate including some areas that were sampled in the 1990s. The report showed locations of the first eight core samples collected with comparison of nitrate profiles to previous time periods, and estimation of nitrate transport rates at each location.
As part of this three-year vadose zone study, approximately 27 sites collected across the CPNRD between 1990 and 1996 have been digitized and are being used to compare recent profiles at these sites to determine how fast nitrate is moving and whether changing land use management has resulted in reduced loading of nitrate in the vadose zone. These sites are all being used for agricultural production. The first eight sample results indicate that lowering nitrogen fertilizer amounts applied, reducing irrigation water applied, and changing land use practices at the surface may be lowering the nitrate concentrations in the vadose zone.
UPDATES TO THE GROUNDWATER QUALITY PROGRAM
January 2016: Southern Hall & northern Hamilton counties (south of the Platte River) were moved from a Phase I to a Phase II Groundwater Management Area. Maps of areas: Hall | Hamilton The board made the change due to increasing nitrate levels in those areas. Levels for Hall County | Hamilton County. The Rules & Regulations require areas with nitrate level concentrations of 7.6 to 15 ppm to be placed in a Phase II area. Because the phases are by area, individual wells in a Phase Area may be higher or lower than the designated range of nitrate concentrations. Other factors, including proximity to a municipal water supply and vadose zone nitrates are also used in determining the Phase Areas. (The vadose zone is the area between the root zone and the water table.)
Each operator must submit an annual report on or before March 31 on forms furnished by the District showing the following data for the upcoming year: All crops must be reported, which would include corn, sorghum, potatoes, beans, alfalfa, small grains, and any other commodity crop.
For crops other than corn, sorghum or potatoes: the legal description, type of irrigation system, and number of wells if greater than 1 well, total unregulated crop acres and crop to be planted. Crops other than corn, sorghum or potatoes do not require soil and water tests.
For corn, sorghum and potatoes for the upcoming year:
– Legal description, type of irrigation system, and number of wells if greater than 1 well.
– Number of acres in corn, sorghum and/or potatoes and the number of field acres irrigated.
– Results of the groundwater nitrate/nitrogen analysis in ppm for each well, with each well identified by legal location to the nearest 10 acre tract,
– Results of the residual nitrate/nitrogen deep soils analysis on each field or 80 acre tract, whichever is less, identified by locations using legal description and showing the irrigation well(s) identified irrigation wells used to irrigate that field,
– Credit for legume crop (beans, alfalfa, etc) and/or manure or sludge applied.
– Crop to be grown and per acre expected yield used as the basis for determining nitrogen needs on each field,
– Recommended commercial nitrogen fertilizer application rate utilizing the District’s University of Nebraska’s formula for commercial nitrogen fertilizer recommendations, and
– On the same annual report due March 31, operators must show the following for the previous crop year: actual commercial nitrogen fertilizer applied per acre on each field, timing of the application(s), if an inhibitor was used, actual inches of groundwater applied per acre on each field, actual yield achieved per acre on each field, and certification by the operator.
Phase I is generally the portion of the District in which the average nitrates are from 0 to 7.5 ppm
Phase II is generally those areas that have an average nitrate concentration of 7.6 to 15 ppm
Phase III is generally those areas with an average nitrate concentration of 15.1 ppm and higher.
Phase IV: Area where nitrate levels are not declining at an acceptable rate.
Because the phases are by area, individual wells in a Phase Area may be higher or lower than the designated range of nitrate concentrations. Other factors, including proximity to a municipal water supply and vadose zone nitrates, are also used in determining the Phase Areas. UNL Videos on Nitrogen Management
Until the Central Platte NRD’s Groundwater Quality Management Program was adopted, the nitrate level in the high Nitrate area of the District had increased at a rate of about 0.5 ppm/year to 19.24 ppm. At the end of the first crop year under the program, the level dropped by 0.3 ppm and continued to drop through the 1993 crop year. Adverse weather conditions resulted in increases during the 1994 and 1995 crop years, but, a lowering of the nitrate rate occurred again after the 1996 and 1997 crop years.
In 1999, nitrate levels in the NRD’s high-nitrate area dropped from 17.41 ppm from spring 1998 to 16.62 ppm spring 1999. The drop is credited to landowners in the District using better management practices recommended by the NRD and the University of Nebraska- Lincoln. Farmers from throughout the District, with varying soils and conditions, were recruited to work with the NRD in using the best management practices to demonstrate that nitrates can be managed efficiently and effectively while maintaining crop yields. In addition, many of the tools needed by the farmers to establish best management practices, including fertilizer calibration meters, irrigation well hour meters, surge valves, vertical dam manifolds, irrigation flow meters and reuse pits, were encouraged through the availability of cost sharing by the District Research indicated that most farmers did not know how much water they were using during irrigation, so the Board decided to make mandatory the practice of monitoring well outputs in Phases II and III. A well measuring program was adopted, and later revised, that could determine how much water is being used. Wells in Phase III must be measured by the NRD by 1998 and in Phase II by 2000.
To facilitate increased water management, the District developed its Splash program to provide one-on-one education for the producer who voluntarily participated. The producer received weekly irrigation assistance on one field and a complete evaluation of his or her irrigation system. In return, the producer is expected to share the experience with other producers and consider improved irrigation techniques. To supplement these education and cost-share funding portions of the program, the NRD adopted rules and regulations to assure that certain minimum changes would occur.
Erosion & Sediment Control Plan (updated January 2017)