Wyoming Department of Environmental Quality
Link to: Wyoming Department of Environmental Quality Groundwater Information
NGWMN Contact:
Cherrie Nelson
307-777-7092
cherrie.nelson1@wyo.gov
The Wyoming Department of Environmental Quality (DEQ) is working to become a water-quality data provider to the National Groundwater Monitoring Network (NGWMN). Since 1973, DEQ has served as the state's regulatory agency charged with protecting, conserving and enhancing Wyoming's land, air and water for the benefit of current and future generations. DEQ currently supports a network of 330 well monitoring sites and is actively working towards serving data from 116 wells to the Portal. DEQ has been a part of the Network since 2017.
DEQ will provide water-quality data from the Colorado Plateaus aquifers, High Plains aquifer, Lower Cretaceous aquifers, Lower Tertiary aquifers, Pacific Northwest volcanic-rock aquifers, Paleozoic aquifers, Upper Cretaceous aquifers, and Wyoming Tertiary aquifers.
NGWMN Projects:
Initial project to become a NGWMN data provider. DEQ will become a new data provider to the NGWMN by connecting their RDBMS database to the NGWMN data portal and selecting and classifying a subset of their wells to be sampled every 5 years.
2021: 7/15/2021 to 7/14/2023
This project is to expand WDEQ wells in the NGWMN. Recently sampled wells and wells in the rest of the state network will be evaluated for inclusion in the NGWMN. Selected sites will be classified and added to the NGWMN.
NGWMN Presentations:
2017 Presentation to new data providers meeting
Site Selection and Classification
Two-hundred ninety-one (291) wells sampled as part of the AGWMP were evaluated for potential inclusion in a state groundwater monitoring network. All of these wells are located in moderate to high priority aquifers, and the wells were evaluated based on the well having the minimum criteria outlined in the Framework Document. Well construction records were used as the primary basis for the network suitability screening. Based on this evaluation, one-hundred sixteen (116) wells were selected as candidates for inclusion in a state groundwater monitoring network. These wells have construction records demonstrating that seals are present to prevent contamination from surface run-off and that any overlying aquifers are isolated from one-another. From the one-hundred sixteen (116) wells, a subset of fifty-three (53) wells were included in the final well selection as the best candidates. These wells were selected based on their spatial distribution within Wyoming's priority aquifers to achieve the best coverage. Specifically, wells were selected in or down-gradient from the portions of the priority aquifers with the greatest sensitivity to contamination, and where available, wells were selected up- and/or down- gradient relative to regional groundwater flow patterns.
Table 1 provides a summary of the number of wells selected for each principle aquifer system. The attached map depicts the location of selected wells relative to the priority aquifer layer developed as part of the Wyoming Groundwater Vulnerability Assessment Project.
| National Aquifer Name | Local Aquifer Name(s) | Number of Wells | Well Depth Range |
|---|---|---|---|
| Table 1. Well Summary | |||
| Alluvial | Alluvial | 5 | 36 to 78 feet |
| High Plains | Ogallala Formation, Arikaree Formation, White River Formation, Chadron Formation, Brule Formation | 12 | 100 to 480 feet |
| Lower Tertiary | Wasatch Formation, Fort Union Formation | 14 | 115 to 421 feet |
| Colorado Plateau | Mesa Verde Formation, Browns Park Formation, Wasatch Formation | 9 | 65 to 420 feet |
| Upper and Lower Cretaceous | Lance Formation, Sundance Formation | 5 | 60 to 360 feet |
| Paleozoic | Casper Formation | 3 | 90 to 300 feet |
| Other | Pre-cambrian | 5 | 140 to 300 feet |
The selected wells are classified as a "surveillance" monitoring network with a minimum sampling frequency of once every five (5) to ten (10) years. The minimum sampling frequency was expanded from a minimum of five (5) to a minimum frequency of once every ten (10) years by the SGW in 2019. Surveillance monitoring provides data to assess long-term natural trends or the effect of slowly changing anthropogenic activities, and can be thought of as a periodic "census" of groundwater quality within the state's priority aquifers. (SGW 2013) To date the selected wells have only been sampled by the WDEQ/WQD one (1) time. As a result, the wells are all currently listed in 600px500
the "baseline" subnetwork until sufficient water quality data is available to assign them as part of background, suspected changes, or documented changes subnetworks.
Wyoming National Groundwater Monitoring Network Project: Well Selection Map
Data Collection Techniques
Field Techniques
Representative well water samples are obtained from wells by purging groundwater until select field parameters have stabilized. Field parameters measured during purging include: temperature, pH, oxidation-reduction potential, specific conductance, dissolved oxygen, and turbidity. Field parameters are measured at least every five (5) minutes. Collection of parameters is generally conducted by utilizing a flow through cell equipped with the applicable sensors.
A minimum of six (6) parameter measurements are collected. If field parameters have not stabilized between the last three (3) readings, purging and parameter measurement continues until stabilization has been achieved. Stabilization can be demonstrated by a variance of no more than +/- 10% for temperature, turbidity (if >10 Nephelometric Turbidity unit (NTU)), dissolved oxygen (if > 0.5 milligrams per liter (mg/L)); +/- 3% specific conductance; +/- 10 millivolts (mV) for oxidation reduction potential; and +/-0.2 standard units for pH.
To measure the purge rate of the well, a 5-gallon bucket and a timer capable of measuring time to seconds is used. Flow rate is estimated by the recording the time it takes to fill a 5-gallon bucket, and converting to a gallons per minute (gpm) reading.
Each non-disposable (not for single-use) piece of equipment used in conjunction with the sampling activities and intended for re-use is decontaminated. A detailed description of field techniques is described in the attached Sampling and Analysis Plan (SAP).
Data Management
The following summarizes the data review used as part of the WDEQ/WQD Quality Assurance process for data collected as part of the AGWMP and ultimately shared with the NGWMN portal.
Data review is conducted in-house to ensure that data has been recorded, transmitted, and processed correctly (as prescribed in the SAP) and includes the following activities: checking for data entry, transcription, calculation and reduction, and transformation errors. Activities also include generating a list of all samples collected (regular samples, blanks, duplicates) as well as the sample information (shipping dates, verification of sample receipt, verification that proper preservatives were used and holding times were met) to ensure that the samples/parameters planned are the same number and type as those actually collected. Data review may occur on a frequent basis for ongoing data collection programs or may only occur a few times during a shorter data collection project.
Laboratory results are initially reviewed and reported by the analyzing laboratory. The reviewed data package is then submitted by the laboratory to the Project Manager, Supervisor, and/or the Quality Assurance Officer (QAO). The Project Manager and /or QAO conducts a review of the lab data. Some (not all) of these checks include making sure Sample IDs are correct, reviewing laboratory comments, comparing total to dissolved values, checking for the presence of expected detection/quantitation limits based on the analytical method, reviewing non-detect data, checking to see if/when dilutions were performed, making sure holding times were met, making sure all analyses for a sample are complete, looking for duplicate records or incorrect dates, etc. The Project Manager or QAO follows up with the laboratory Quality Assurance (QA) officer or individual analysts if any missing or suspect data is identified. Laboratory results passing this initial level of scrutiny are then uploaded for storage in the ArcSDE database and the raw data files are saved on the WDEQ/WQD Groundwater Section server indefinitely.
Field personnel verify quality of field data (electronic and hard copy). Field data for the entire trip is reviewed by a member of the field team both during and after the trip. This review includes the following: checking field documentation and electronic field data for data entry, transcription, calculation and reduction, and transformation errors as well as completeness, proper format, and initial filing into the proper location. Next, the field documentation may be sent to the QAO for review, or it may be submitted at the same time as the final report. The QAO will perform a secondary check of the above-listed items, follow up on questionable data points, and provide a Quality Assurance/Quality Control (QA/QC) report.
Other Agency Information
Aquifer Prioritization for Ambient Groundwater Monitoring