Digital map of the elevation of base of the upper layer of the phase-three Elkhorn-Loup Model, north-central Nebraska
Description
In 2006, a cooperative study was established to compile reliable data describing groundwater
and surface-water interactions in the Elkhorn and Loup River Basins. The purpose of the study
was to address state legislation that requires a sustainable balance between long term water
supplies and uses of surface water and groundwater. A groundwater-flow model [hereinafter
referred to as the Elkhorn-Loup Model (ELM)] was constructed as part of the first two phases
of that study as a tool for understanding the effect of groundwater pumpage on stream base
flow and the effects of management strategies on hydrologically connected groundwater and
surface-water supplies. The third phase of the study was implemented to gain additional geologic
knowledge and update the ELM with enhanced water-budget information and refined discretization
of the model grid and stress periods. As part of that effort, the ELM is being reconstructed to
include two vertical model layers, whereas phase-one and phase-two simulations (Peterson and
others, 2008; Stanton and others, 2010) represented the aquifer system using one vertical model
layer. The goal for defining the base of the upper model layer was to divide the model vertically so
that the upper layer had different water transmitting and storage characteristics than the lower layer.
Texture descriptions were used in most cases to identify the depth in a test-hole, water well, or
surface-geophysical log at which dividing the aquifer produced contrasting texture characteristics
for the upper and lower model layers. The study area covers approximately 30,000 square miles,
and extends from the Niobrara River in the north to the Platte River in the south. The western
boundary roughly coincides with the western boundary of the Upper Loup NRD, and the eastern
boundary roughly coincides with the approximate location of the westernmost extent of glacial till
in eastern Nebraska (University of Nebraska, 2005). This data release consists of a line shapefile
of contours attributed with values representing the elevation of the base of the upper layer of the
two-layer phase-three ELM above the vertical datum (National Geodetic Vertical Datum of 1929).
Resources
| Name |
Format |
Description |
Link |
|
55 |
Landing page for access to the data |
https://doi.org/10.5066/P9P0RJOB |
|
55 |
The metadata original format |
https://data.usgs.gov/datacatalog/metadata/USGS.57b942b1-ea27-4e29-b2c3-027016a173ab.xml |
Tags
- elkhorn-loup-model-area
- geohydrologic-units
- high-plains-aquifer
- elevation
- ogallala-aquifer
- geoscientificinformation
- aquifer-characteristics
- inlandwaters
- usgs
- aquifer-base
- usgs-57b942b1-ea27-4e29-b2c3-027016a173ab