Bringing high-tech hydrogeologic data down to earth.
By Jesse Korus, Ph.D., PG
Water well professionals are keenly aware having accurate hydrogeological information can mean all the difference between a successful job and an unsuccessful one.
Data on the thickness and extent of aquifers and confining units, for example, informs contractors on how to design and construct wells, comply with local regulations, and prepare a competitive bid. Data on groundwater chemistry is essential for locating and developing a suitable drinking water supply. Information about groundwater levels helps determine screened intervals and depths of pumps.
But data is becoming increasingly complex.
Recently, advancements in technology and computer processing have brought airborne geophysics into the mix. Airborne geophysical surveys allow rapid large-scale mapping of geological strata, aquifer boundaries, and saline groundwater.
This technology is a game-changer for mapping complex hydrogeology, but the vastness and complexity of the data it creates can boggle the mind. Moreover, it can be difficult for hydrogeologists to translate this information into a format water well professionals can use.
Is there an effective way to gather data and transfer information between experts and end-users?
Data Integration in the Cloud
A team of hydrogeologists and groundwater practitioners in Nebraska are aiming to provide a cloud-based information solution for high-tech hydrogeologic data.
The University of Nebraska-Lincoln is teaming with local, state, and federal agencies to build the Nebraska GeoCloud (NGC), which is designed to integrate data from multiple sources and make it available through a web service. The team has hired I-GIS of Denmark, a firm specializing in software for hydrogeologists, to customize a data management system for Nebraska.
The basic concept behind the NGC is data integration. The system combines data from airborne geophysics, borehole geophysics, cuttings, cores, groundwater chemistry, groundwater levels, maps, and other sources—and seamlessly connects it to 3D visualization software and geographic information systems.
Using a dynamic map interface, hydrogeologists will be able to draw a box around a region of interest, connect to all of the data for that region, build a simplified hydrogeological model, and then upload the model back to the NGC where water well professionals can access it.
The centerpiece of the NGC is a database containing nearly 15,000 miles of airborne electromagnetic surveys completed in Nebraska since 2007.
Airborne electromagnetics (AEM) is a geophysical technique permitting rapid surveying of large areas for a relatively low cost. AEM works by generating an electromagnetic field that interacts with Earth materials, yielding information about the geophysical properties of the subsurface. The technique is similar to a CAT scan or MRI—it allows us to “see” inside the body of the Earth.
By combining AEM data with information from boreholes and wells, hydrogeologists can interpret geologic units, groundwater salinity, and other important details that cannot be determined from boreholes alone.
Hydrogeologists at the University of Nebraska-Lincoln’s Conservation and Survey Division, part of the School of Natural Resources, have seen the benefit taking such a look. They recently discovered a complex, intersecting network of buried valleys in southeast Nebraska using AEM data. Some buried valleys are filled with sand and gravel, others with silt and clay.
Local water well contractors have been confounded for decades by the dramatic changes in well yield, drawdown, and water chemistry from one location to another. What was once thought to be a random distribution of aquifers is now known to be an orderly network of buried valleys. The model has improved predictions of well yields and water quality in this area.
Serving the End-Users
The Nebraska GeoCloud will serve a variety of other purposes as well.
Hydrogeologists at the Conservation and Survey Division routinely serve contractors by gathering and translating data from AEM, boreholes, and groundwater monitoring. The NGC will integrate data from all of these sources and streamline its transfer to the end-user.
In some areas of Nebraska, well permit regulations require a minimum saturated thickness for new high-capacity wells. Information from the NGC will help contractors and permitting agencies determine whether a proposed well location is likely to provide the adequate aquifer thickness.
Another benefit involves visualizing groundwater chemistry in the context of a 3D hydrogeological model.
At a recent NGC workshop in Lincoln, project sponsors trained with a model of a two-layer aquifer system contaminated with nitrate nitrogen. Attendees used hypothetical situations to make decisions about placing and constructing wells in the complex aquifer system. The 3D virtual environment made it possible to view the water quality and geology together in 3D to evaluate different options. As a bonus, workshop attendees earned continuing education credits for their water well licenses.
Partnerships Are Key to Success
Nebraska has been engaged in the collection and management of groundwater data for nearly a century and has developed top-notch information systems for water wells and hydrogeology. These systems are the direct result of successful public-private and public-public partnerships.
The Nebraska Well Driller’s Association, for example, was founded in 1929 by forward-thinking water well contractors and geologis—making crucial ties between the water well industry, government, and the University of Nebraska-Lincoln that persist today. The NGC continues this history of collaboration and seeks to derive outcomes beneficial for all involved.
The NGC will help water well professionals make sense of—and benefit from—the bewildering masses of data permeating this high-tech information-driven age.
Although full completion of the system is expected by July 2018, other states are already looking to the Nebraska GeoCloud as a model for managing airborne electromagnetic survey data and related hydrogeologic information.
________________________________________________________________________________________Jesse Korus, Ph.D., PG, is an assistant professor in the Conservation and Survey Division, which is part of the School of Natural Resources at the University of Nebraska-Lincoln. He has 14 years of experience in geology, hydrogeology, and applied geophysics. Korus is lead investigator of the Nebraska GeoCloud project, which is funded through Nebraska’s Water Sustainability Fund and involves multiple partners, including Nebraska’s natural resources districts and the U.S. Geological Survey.