Interpretation of Hydrogeologic Data to Support Groundwater Management, Bazile Groundwater Management Area, Northeast Nebraska, 2019—A Case Demonstration of the Nebraska Geocloud

Scientific Investigations Report 2020-5113
Prepared in cooperation with the Nebraska Natural Resources Commission; Nebraska Department of Natural Resources; and Lower Platte North, Lower Platte South, Papio-Missouri River, Nemaha, Lower Loup, Central Platte, Upper Elkhorn, Lower Elkhorn, Lower Niobrara, and Lewis and Clark Natural Resources Districts
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Links

  • Document: Report (4.39 MB pdf)
  • Tables:
    • Table 4 (17.9 kB xlsx) — Monitoring wells completed in the High Plains aquifer where continuous water-level data were recorded within the Bazile Groundwater Management Area, 2013–18
    • Table 4 (6.47 kB csv) — Monitoring wells completed in the High Plains aquifer where continuous water-level data were recorded within the Bazile Groundwater Management Area, 2013–18
    • Table 5 (23.2 kB xlsx) — Summary of selected water-quality data and groundwater age estimates from wells sampled within the Bazile Groundwater Management Area, 2000–17
    • Table 5 (12.1 kB csv) — Summary of selected water-quality data and groundwater age estimates from wells sampled within the Bazile Groundwater Management Area, 2000–17
    • Table 6 (16.6 kB xlsx) — Pesticide concentration, nitrate concentration, and calculated apparent groundwater ages for sampled monitoring and irrigation wells with detectable concentrations of pesticides, 1995–2005
    • Table 6 (8.17 kB csv) — Pesticide concentration, nitrate concentration, and calculated apparent groundwater ages for sampled monitoring and irrigation wells with detectable concentrations of pesticides, 1995–2005
  • Data Release: USGS data release — Interpolated groundwater-level surface, spring 2017, Bazile Groundwater Management Area, northeastern Nebraska
  • Version History: Version History (585 B txt)
  • Download citation as: RIS | Dublin Core

Abstract

Nitrate, age tracer, and continuous groundwater-level data were interpreted in conjunction with airborne electromagnetic (AEM) survey data to understand the movement of nitrate within the Bazile Groundwater Management Area (BGMA) in northeastern Nebraska. Previously published age tracer data and nitrate data indicated vertical stratification of groundwater quality. Younger groundwater sampled within shallow parts of the aquifer had higher concentrations of nitrate, with 70 percent exceeding the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter. In contrast, groundwater sampled from deeper parts of the aquifer indicated that nitrate concentrations were less than 2 milligrams per liter and that groundwater likely recharged prior to widespread use of commercial fertilizer.

The hydrostratigraphic interpretation of AEM profiles indicated that shallow and deep monitoring wells were often screened within the same homogenous zone of aquifer material. In contrast, test-hole logs indicated that there often are fine-grained layers within these homogenous zones that separate the shallow and deep monitoring well screens, but these fine-grained layers are not detected by the AEM technique because of decreased resolution of the AEM technique with depth.

The stratification of groundwater ages and nitrate concentrations likely was caused by groundwater-flow paths of different length, location and time of recharge, and denitrification. Within paleochannels interpreted from AEM and test-hole data, pesticides detected in groundwater generally coincide with elevated nitrate concentrations. Continuous groundwater-level data from four monitoring well nests indicated that groundwater pumping can impose or increase downward hydraulic gradients and facilitate the downward movement of nitrate into deeper parts of the High Plains aquifer. Given the density of irrigation wells within the BGMA, this effect on the hydraulic gradient is likely prevalent in other areas of the BGMA. Understanding seasonal water-level changes can allow water managers to better predict and assess the hydraulic gradient and the vulnerability of groundwater in deeper parts of the High Plains aquifer.

Nitrate, age tracer, and continuous groundwater-level data within the BGMA were interpreted in conjunction with AEM data as a case demonstration of the Nebraska Geocloud. The Nebraska Geocloud was initiated to protect taxpayer investments in AEM data collection and realize maximum benefit of these data by creating a publicly available, online digital database for long-term data storage. The Lower Platte North, Lower Platte South, Papio-Missouri River, Nemaha, Lower Loup, Central Platte, Upper Elkhorn, Lower Elkhorn, Lower Niobrara, and Lewis and Clark Natural Resources Districts; the University of Nebraska-Lincoln Conservation and Survey Division, Nebraska Natural Resources Commission, Nebraska Department of Natural Resources; and the U.S. Geological Survey entered a cooperative agreement to begin a program of data management and research aimed at understanding the best use of AEM for groundwater sustainability and management. Resulting case-study interpretations are provided to guide use of the Nebraska Geocloud to assess water-quality conditions and can be used by water managers and staff to address applicable water resource problems.

Suggested Citation

Hobza, C.M., and Steele, G.V., 2020, Interpretation of hydrogeologic data to support groundwater management, Bazile Groundwater Management Area, northeast Nebraska, 2019—A case demonstration of the Nebraska Geocloud (ver. 1.1, December 15, 2020): U.S. Geological Survey Scientific Investigations Report 2020–5113, 46 p., https://doi.org/10.3133/sir20205113.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Hydrologic Data Compilation and Analysis
  • Interpretation of Hydrogeologic Data
  • Potential Future Data Collection to Inform Groundwater Management
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Interpretation of hydrogeologic data to support groundwater management, Bazile Groundwater Management Area, northeast Nebraska, 2019—A case demonstration of the Nebraska Geocloud
Series title Scientific Investigations Report
Series number 2020-5113
DOI 10.3133/sir20205113
Edition Version 1.0: December 10, 2020: Version 1.1: December 21, 2020
Year Published 2020
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Nebraska Water Science Center
Description Report: viii, 45 p.; Tables: 4, 5, and 6 (.xlsx and .csv); Data Release; Version History
Country United States
State Nebraska
Other Geospatial Bazile Groundwater Management Area
Online Only (Y/N) Y
Additional Online Files (Y/N) Y
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