English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

This report describes an interactive tool (NDakGWtool) in which a statistical model is developed using locally weighted regression to estimate monthly mean groundwater elevations for a specified latitude and longitude, referred to as the “user-specified location.” For each user-specified location, seven models are developed for each month from April through October. Localized, high spatial-resolution maps of estimated monthly mean groundwater surface elevations are produced from the models. The tool was evaluated for glacial drift aquifers of the 32-county study area in central and eastern North Dakota. Although groundwater elevations from 1960 to 2017 were available to develop the tool, groundwater elevations from 1995 to 2015 were used for model testing and development of the model domain. There are 413 grid cells of 0.1-degree latitude by 0.1-degree longitude size in the model domain, and the tool produces maps of estimated monthly mean groundwater surface elevations for the cell containing the user-specified location. Additionally, the NDakGWtool produces maps of estimated groundwater depth below land surface and ArcGIS files of estimated groundwater surface elevations and groundwater depth below land surface. The tool is composed of four main components: data input, statistical model, output, and user-interactive process. Introduction The Natural Resources Conservation Service (NRCS) commonly completes hydrologic analyses to determine the effects of proposed agricultural projects, for example, drain tile installation or irrigation withdrawals on shallow groundwater and surface-water resources. A criterion commonly used for their analysis is the 50-percent chance annual probability of inundation for 15 consecutive days during the wetland growing season (U.S. Department of Agriculture, 2015). As a result, in the hydrologic analysis, the NRCS commonly uses groundwater elevations in nearby observation wells to interpolate a seasonal minimum groundwater elevation for the specific location of the proposed project. In North Dakota, an online database hosted by the North Dakota State Water Commission (NDSWC) provides extensive spatial coverage of groundwater and surface-water data from various sources with about 8.5 million measurements for about 37,000 sites (fig. 1; North Dakota State Water Commission, 2017). Groundwater elevations are available from many types of wells, such as domestic, industrial, irrigation, municipal, observation, and production, but only about 10,000 groundwater sites have at least 1 groundwater measurement. Elevation is defined herein as the altitude of groundwater in feet above the North American Vertical Datum of 1988 (NAVD 88). For sites containing groundwater elevations, there is large variation in measuring periods, many wells have been discontinued or added, and measuring frequencies and seasonal coverage vary extensively. Furthermore, geologic and hydrologic conditions represented by a well network can vary substantially from well to well, and groundwater elevations are affected by spatially and seasonally variable recharge and discharge conditions and pumping. Culling pertinent groundwater elevations from millions of wells in the existing NDSWC database can be an onerous task, and, depending on the project location, availability of nearby wells, and complexity of the groundwater hydrology, it may be difficult to interpolate groundwater elevations in the location of a proposed project. To address this need, the U.S. Geological Survey (USGS), in cooperation with the NRCS, developed an interactive tool (NDakGWtool) to produce estimates of monthly mean groundwater surface elevations for a userspecified location within glacial drift aquifers for a 32-county study area in central and eastern North Dakota (fig. 1). The NDakGWtool will be useful to the NRCS and for future groundwater investigations by the USGS, NDSWC, and other agencies. Purpose and Scope The purpose of this report is to describe the development of an interactive tool (NDakGWtool) used to estimate monthly mean groundwater elevations in central and eastern North Dakota and to illustrate use of the tool. The tool was evaluated for glacial drift aquifers of a 32-county study area in central and eastern North Dakota and the 4 main components of the tool are data input, statistical model, output, and userinteractive process (fig. 2). 2 Interactive Tool to Estimate Groundwater Elevations in Central and Eastern North Dakota

Interactive tool to estimate groundwater elevations in central and eastern North Dakota