Central Platte Natural Resources District (CPNRD). In several areas of this NRD nitrate-nitrogen levels in the groundwater were increasing on the order of .5 ppm per year, and were in excess of 25 ppm. Recall that the federal standard is 10 ppm.
The CPNRD chose to act in the mid 1980's with the regulations for a sophisticated nitrate-nitorgen management plan in any NRD area that exceeded their trigger criteria. The program actually uses three phases based on ambient nitrate-nitrogen levles with each successive phase having stricter requirements. The overall plan called for reductions in fertilizer applications by several methods - monitoring groundwater levels and subtracting this source of nitrogen from application rates, education on more optimum nitrogen applicaton rates, restricted application times and the power of positive reinforcement - if the area's nitrate rates start falling, additional monitoring can be averted.
Bottom line, most of the areas are seeing a reversal of trends. On average, the NRD pre-program rate of change was an increase of nitrate-nitrogen of about .5 ppm per year. Today, most areas are seeing a trend of a .25 ppm decrease per year. On the broader scale, the once average concentration of 19+ ppm is now about 14.5 ppm. And it was all done without sacrificing production levels and farm income. I guess you could argue that after 20 years or so the groundwater is still above the federal level, but in my opinion that'd be missing the larger point. I have to congratulate the CPNRD on a program well done.
I'd also be remiss if I didn't mention that this effort is now being done without the data support FSA used to provide - on crop types and acreages and landowner and farm operator information. The elimination of this data support has caused the NRD significant added expense to keep this program running. I have blogged on this before here. It seems a shame to me that the federal government will not help state and local governments with this data support. 'Nuf said.