Illinois State Water Survey

Link to: Illinois State Water Survey Groundwater Information

NGWMN Contact:

Dan Hadley (Illinois State Water Survey, Data Management)

(217) 300-0402

Jason Thomason (Illinois State Geological Survey, Drilling)

217-244-2508

jthomaso@illinois.edu

The Illinois State Water Survey (ISWS) is a water-level data provider to the National Groundwater Monitoring Network (NGWMN). ISWS participated in the NGWMN Pilot project and has since added 61 well sites to the Portal. ISWS works to assess aquifer recharge and reductions in natural groundwater discharge to streams; provide data to calibrate groundwater flow models, and to Monitor the impacts of withdrawals (irrigation, public supply, and industrial) on water availability. ISWS has been a part of the Network since 2015.

ISWS provides water-level data from the Sand and gravel (glaciated), Cambrian-Ordovician, Silurian-Devonian, and the Pennsylvanian aquifers.

The Illinois State Water Survey (ISWS) coordinates with the Illinois State Geological Survey (ISGS) to do well drilling and well maintenance work on NGWMN sites.

NGWMN Products:

NGWMN Illinois/Indiana Pilot Report

Projects:

2015: 9/1/2015 to 8/31/2016 (ISWS)

Initial project to become a NGWMN data provider. Completed work started during pilot project.

2016 Round 1: 9/1/ 2016 to 8/31/2018 (ISWS)

Project is to support maintenance of connections to the NGWMN Portal. Support is also provided to keep site information up to date in agency databases and in the NGWMN Well Registry.

2016 Round 2: 9/1/ 2016 to 8/31/2018 (ISWS)

Project is to do well maintenance activities at nineteen sites that will then be added to the NGWMN. Shallow wells with be redeveloped with compressed air or a submersible pump and will have slug tests conducted to evaluate well-integrity. Well integrity evaluation at the deep wells will involve comparison of water-levels from nearby wells. Three deep wells also will be monitored as part of aquifer tests conducted using nearby production wells.

2017: 7/1/2017 to 12/31/2018 (ISGS/ISWS)

Project is to install a minimum of 5 new observation wells in the Sand and Gravel Principal aquifer. Locations are proposed in Kane County.

2019 Round 1: 7/15/2019 to 12/31/2020 (ISGS/ISWS)

Project is for the ISWS to provide persistent data services for 1 year. The ISGS will drill at least 5 new wells to fill gapsin the NGWMN.

2020 Round 1: 9/1/2020 to 8/31/2022 (ISGS/ISWS)

Project is to provide persistent data services for one year to ensure that data continues to flow to the NGWMN Data Portal, and that sites and site information are up to date. They will also drill 5 new wells to fill gaps in the NGWMN. Four wells will be in the Sand and Gravel Principal aquifer and one will be in the Silurian-Devonian Principal aquifer.

2020 Round 2: 11/16/2020 to 11/15/2021 (ISGS/ISWS)

Project is to do geophysical logging and surface geophysics at two wells proposed for drilling during Round 1.

NGWMN Presentations:

December 2016 presentation to SOGW

Site Selection and Classification

Site Selection

Almost all monitoring wells within Illinois' local monitoring networks fall within a major aquifer. Monitoring sites were selected primarily based on the current or planned availability of high-frequency water level data collection, mostly among existing networks for which there is funding available for continued monitoring. Availability of complete lithologic and well construction data was also an important consideration, though a handful of locations were chosen for length of historical data record in spite of missing some of these data elements.

Since bedrock monitoring sites were not included in the NGWMN pilot project, focus was given to adding these sites in the Portal. Bedrock monitoring sites are more common in northern Illinois. The Cambrian-Ordovician Aquifer system, particularly the confined St. Peter and Ironton-Galesville Sandstones, has been the subject of many synoptic measurements by the ISWS since 1959, but there are relatively few sites appropriate for the NGWMN as most sandstone monitoring historically has been done at active production wells (Abrams et al., 2015); sites were only considered if cooperative agreements providing access to abandoned wells were established, or the wells are otherwise maintained as dedicated monitoring wells by the ISWS, most of these are being outfitted with transducers and telemetry. In total, 14 sandstone monitoring wells were added to the NGWMN. Several of these sites have additional historical data in the form of Stevens Recorder charts, so the length and frequency of historical data will improve as it is entered into the database.

The monitoring network was also expanded in the major sand and gravel aquifers. In the Mahomet Aquifer, additional sites were selected to fill data gaps that were present from the initial pilot study for the NGWMN. The Sankoty Aquifer in northwestern Illinois is another irrigated sand and gravel aquifer system that has been monitored by the Survey since 1991 (Burch, 2004); no sites were currently part of the NGWMN, so all four sites with transducers (seven wells) were added to the network. Wells within the Water and Atmospheric Resources Monitoring (WARM) network, which is a statewide Illinois monitoring network focused on real-time climate data and water table conditions, were another addition to shallow monitoring in the NGWMN. WARM wells were considered for inclusion in the NGWMN if they were part of a major aquifer system. This includied two wells in sand and gravel aquifers in northeast Illinois, and one in the sand and gravel aquifers near St. Louis.

Site Classification

The ISWS wells currently part of the NGWMN are a mix of "Trend" and "Surveillance" wells. Most wells currently in the network will be outfitted with telemetry and transducers in the coming years, so wells that are classified as "Surveillance" will change to "Trend". Shallow monitoring wells, both in the Sand and Gravel and shallow bedrock units, are classified as a mix of "Background" and "Known Changes", mainly dependent on the proximity to irrigation. In contrast the vast majority of the Cambrian-Ordovician wells are classified as "Known Changes" as the system continues to be heavily stressed by municipal and industrial withdrawals, especially near the Chicago suburbs in northeast Illinois.

Data Collection Techniques

Water level measurement protocols are documented in ISWS Standard Operating Procedures, which are currently undergoing revision to add a section for transducer measurements and update language. Practices follow those outlined in Appendix 5 of the NGWMN Framework Document. Additional documentation for ISWS procedures for water level measurement and groundwater sampling can be found in Barcelona et al. (1985).

Data Management

Per the guidelines in Appendix 5 of the NGWMN Framework Document, the ISWS populated well information required as part of the minimum data elements for the Well Registry and web services for the NGWMN Portal. Most data elements came from the ISWS wells table in SQL Server, which contains pertinent information for over 400,000 domestic, industrial, irrigation, and public supply wells in Illinois, particularly since well construction reporting became required in 1967. Wells in the ISWS database are identified with a unique 'P' number, typically six digits, along with a local Site Name. Basic geologic and well information, including National Aquifer, Local Aquifer Name, well depth, open interval, and whether the aquifer is confined were garnered from the lithological and well construction data. Although the ISWS database contains information about well construction, establishing a lithology and well construction table for inclusion in the NGWMN data services required supplementing ISWS data with lithological and well construction data from the Illinois State Geological Survey (ISGS) database, who traditionally maintains these records. As both Surveys are part of the Prairie Research Institute (PRI), long term the ISGS lithology and well construction data is expected to be linked directly to the ISWS database as the two Surveys work through procedures to combine workflows and link relevant records.

All Illinois State Water Survey data provided to the NGWMN is hosted internally behind a firewall protected MS SQL Server database while the web services delivering data to the NGWMN portal are deployed on a public facing ISWS data server.