Nemaha NRD - Hydrogeologic Map Book Update & Geodatabase Deliverable

The Nemaha Natural Resources District (NRD) is one of 23 NRDs that manage and regulate groundwater resources in Nebraska.  Because the number of high-capacity wells for irrigation in recent years has expanded, the NRD was interested in establishing groundwater management areas (GWMA) to better manage and regulate existing and future water use.  As part of this process, the NRD wanted to better understand the hydrogeology for the entire NRD (Study Area).  To assist the NRD in this endeavor, LRE Water team members completed a comprehensive hydrogeologic assessment by reviewing available and relevant hydrogeologic data, updated a detailed map book, and provided the NRD with a complete geodatabase deliverable.

DATA ANALYSIS AND MAPPING

Due to the size of the NRD, the large data sets and published map file formats, and compilation requirements of the data, GIS software (ESRI ArcGIS 10.7) and Microsoft Excel were used to manage, evaluate, and visualize the data. The compilation and analysis of the data, and evaluation of the generated maps, enabled the identification of the major aquifers, hydrostratigraphic units, and major groundwater flow systems across the NRD.  Some of the maps generated included:

• Ground surface topography
• Perennial streams and rivers
• Hydrogeologic cross sections
• Bedrock geology and surface topography
• Locations and density of high-capacity wells
• Depth to groundwater
• Groundwater elevation surface
• Thickness and extent of saturated sands and gravels
• Transmissivity of principal aquifers
• Well hydrographs