06/06 - NRDs team on Bazile Groundwater Management Area
Northeast Nebraska’s Upper and Lower Elkhorn, Lewis and Clark, and Lower Niobrara Natural Resources Districts have teamed to help local producers increase nutrient efficiency through cost shares and outreach to improve groundwater quality in parts of three counties that have been battling contamination from nitrogen fertilizer.
Consumption of groundwater with nitrate-N above the U.S. Environmental Protection Agency (EPA) maximum contaminant level of 10 parts per million has been linked to a number of human health concerns, including blue baby syndrome (methemoglobinemia) which can reduce the ability of blood to carry oxygen in infants, unborn children, and the elderly.
Previous groundwater quality studies, including those conducted by the University of Nebraska-Lincoln’s Conservation and Survey Division that began more than 25 years ago, noted area aquifers are particularly vulnerable to contamination, primarily from agricultural sources of nitrogen. Historical use, and in some cases overapplication of fertilizer, has led to increased concentrations of groundwater nitrates. Increasing groundwater nitrates is a common problem throughout Nebraska, though this region of the state has been dealing with the issue for many decades.
“Nitrate contamination in northeast Nebraska has been a source of debate and study since the late 1970s. In an area where much of the drinking water for rural and municipal sources comes from the underlying aquifer, the slow and steady increase in groundwater nitrates has become a focus of local and state action,” said Ben Beckman, a research and extension communications specialist for the Nebraska Water Center, Daugherty Water for Food Global Institute and Nebraska Extension at UNL.
To get an idea of the scope of the project, BGMA is a 756 square mile region covering portions of Antelope, Knox, and Pierce counties. The area has a population of more than 7,000 and a complex mixture of heavily farmed, well drained sandy soils and shallow water tables that contribute to a “perfect storm” for groundwater nitrate contamination.
To help find practical and lasting solutions to this issue and restore groundwater quality in northeast Nebraska, the four northeast Nebraska NRDs joined forces with local producers and state agencies six years ago to create the Bazile Groundwater Management Area (or BGMA) to promote practices addressing rising nitrate levels.
With a recent EPA grant and support from the U.S. Department of Agriculture/Natural Resource Conservation Service through the National Water Quality Initiative BGMA will provide cost sharing assistance to producers who implement best management practices (BMPs) like flow meter installation, deep soil and vadose zone nitrate sampling, crop tissue analysis, soil moisture sensor utilization, and improved timing and type of fertilizer application.
Incentivizing practices that help producers manage natural resources more efficiently, as well as stay profitable through better efficiency of applied nutrients and water will hopefully bring about a lowering of groundwater nitrate levels.
Ideally, BGMA will lead to an overall decrease in excess nitrogen lost from the soil leaving more available for crops to use. While reduced nitrate losses from the crop rooting zone may not be reflected immediately in the aquifer, a reduction in groundwater contamination will eventually show up as declining groundwater nitrate concentrations.
Promotion of these practices is paired with educational outreach to all members of the community, Beckman said.
Increasing awareness by local residents on the impact their actions will have on local water quality is one more step in reducing nitrate loading.
Finally, there is a commitment to partnering with groups like the UNL Water Sciences Laboratory, Nebraska Water Center, and Nebraska Extension to provide research and gather relevant and practical data for more informed decision-making.
“Better understanding of factors that lead to nitrate formation and movement once it has left the root zone where it is available to plants or the slow but steady movement of groundwater itself can help direct funds towards programs that will create the most impact,” Beckman said.
Improved nutrient and fertilizer management can have an impact on groundwater nitrate concentrations. For example, similar circumstances of sandy soils and shallow water tables in the Platte River valley led the Central Platte NRD to create a Groundwater Quality Management Program 30 years ago. Subsequent voluntary management efforts by producers there have led to a slowing and stabilizing of groundwater nitrate levels, said Beckman.
Problems with groundwater contamination are showing up with greater frequency in many areas of Nebraska and the U.S. And nitrates are not the only chemical that may end up in drinking water where sandy soils, heavy water use or improper/outdated well construction can allow pesticides, bacteria, and other contaminants such as uranium and arsenic to enter water supplies at levels threatening human health.
Increases in naturally occurring arsenic and uranium in groundwater may be linked to nitrates and any of these occurring above the maximum EPA contaminant level means having to relocate drinking water wells or installation of expensive water treatment equipment.
“While groundwater quality issues are not an easy or quick fix, the commitment of resources and cooperation between stakeholders in the BGMA is another great example of Nebraskans working together to help make drinking water safer for all,” said Beckman.