2016 NGWA Groundwater Summit: Alphabetical Content Listing
2016 Birdsall-Dreiss Distinguished Lecture: Fluid Induced Earthquakes: Insights from Hydrogeology and Poro-mechanics
2016 NGWREF Darcy Lecture: Seeing Things Differently: Rethinking the Relationship Between Data, Models, and Decision-Making
Ty P.A. Ferré, Ph.D.
Application of 129I/127I Ratios in Groundwater Studies Conducted at Los Alamos National Laboratory, New Mexico
Patrick Longmire, PhD
Investigating the Upper Pierre Aquifer through Regional and Site-Specific Data and Data Integration into a GIS
Theresa Jehn-Dellaport, P.G.
Oil and gas exploration drill-hole geophysical logs have been the primary regional source of data for interpretation of the geometry of the Upper Pierre aquifer. The geophysical logs display a conspicuous spontaneous potential (SP) and resistivity signature within the aquifer, with a distinct low-amplitude deflection in both the SP and resistivity mid-way through the thickness of the aquifer, indicative of the Pierre Ash. Site-collected data, such as lithologic logs, sidewall cores, and drill cuttings suggest the aquifer to be composed of grey siltstone/sandstone with a calculated specific yield value of 0.17.
A database of over 400 interpreted oil and gas geophysical logs was integrated into a Geographic Information System (GIS). The data were processed to geostatistically create continuous surfaces representative of the upper and lower elevations of the aquifer. Spatial characteristics of the aquifer, such as its relation to other aquifers and areas of subcrop and outcrop, have also been defined using GIS capabilities. Hydrogeologic cross-sections and three-dimensional renderings are being used as key decision-making tools for interested parties in adjudicating the groundwater of the Upper Pierre aquifer.
Daniel Soeder, National Energy Technology Laboratory
Although these sensors perform well in a laboratory environment, deploying them in the field for environmental monitoring is challenging. Along with power supply and data storage issues, the major problem is moisture condensation in the sensor, which can create data inconsistencies. Field deployment of the laser sensor for continuous monitoring of methane in the headspace of a groundwater well required the use of a commercial gas drying method to remove humidity. Low power requirements were critical. As configured, the field-deployable device collects an air sample from the well headspace, pumps it through a drying system, and then into the laser sensor to measure methane concentration. Ambient temperature and pressure are also measured before discharging the gas. The entire unit is contained within a medium-size utility box, and field sampling requires only the insertion of a 5 mm (1/4 inch) collection tube into the monitoring well headspace. Field tests are ongoing in support of a patent application.
Todd K. Knause
The HPT was advanced down into a heterogenous alluvial deposit to a depth of 100 feet or refusal. The hydrogeologic data collected was used to evaluate where to collect discrete soil and groundwater samples, and set monitoring well screens during the subsequent Sonic drilling activities. The pressure, flow, and electrical conductivity (EC) data is recorded on a series of logs providing real time high resolution site characterization data. The injection pressure logs were used to infer hydrostratigraphy, including transmissive zones that may represent potential preferential migration pathways for groundwater contaminants and low permeable zones that may act as confining layers. The EC measurements were used to evaluate lithology and potential Total Dissolved Solids (TDS) impacts to groundwater. Discrete groundwater samples were collected from highly transmissive zones, field tested for specific conductance, and submitted to a laboratory for TDS analysis to establish an appropriate ratio of conductivity to TDS. Lithologic interpretations were confirmed by continuous soil cores collected with a Sonic drill rig during monitoring well installations. Disturbed and undisturbed soil samples were collected and analyzed for chemical and physical properties.
Bob Peters, PE
Remotely monitoring, logging and transmitting information, using report by exception technology is critical to proactively managing animal waste and its impact on ground water.
Integrating data logging monitors with industrial data gateways is practical, efficient and cost effective. A variety of telemetry options links hardware in the field to a secure, cloud-based interface. The result is big data that can be analyzed, viewed and configured and acted upon in real time anywhere.
Mark Maimone, PhD, PE, D WRE, BCEE
Groundwater monitoring wells have been installed adjacent to GSI to answer the basic question of the impacts of urban infiltration on the water table and potential flooding of nearby basements, particularly in right-of-way systems (rain gardens, infiltration tree trenches, etc.). Monitoring well data are coupled with continuous monitoring data collected within the GSI to evaluate the magnitude and timing of water table increases due to different storm events and the recovery period when the water table recedes to baseline depths (pre-storm conditions). Monitoring wells are also being routinely monitored at a regional scale to evaluate how the regional water table is responding to large scale implementation of GSI.
Philadelphia Water is using monitoring data to develop design guidelines, assess infiltration impacts, and to show regulatory agencies how GSI can be an effective means of reducing combined sewer overflows.
Electric water-level measurement tapes are generally assumed to be accurate to ±0.01 foot (ft), but little information is available from the manufacturers and USGS field office calibration and initial calibration studies by the USGS Hydrologic Instrumentation Facility (HIF) indicate that this accuracy is seldom attained. This study was designed initially to determine the accuracy of six models of new, unused electric groundwater tapes often used by the USGS for routine water-level measurements and groundwater studies. A tape-calibration system was designed and built at the HIF. The tape-calibration system compares the length of each electric tape to a calibrated-steel reference tape and measures each probe’s activation accuracy. The tape-length accuracy combined with the probe-activation accuracy gave the overall measurement accuracy of the tape. Results demonstrated that none of the electric-tape models tested consistently met the suggested accuracy of ±0.01 ft, and that most tapes were accurate to approximately ±0.05 ft per 100 ft without additional calibration. Precise calibration of in-use tapes is necessary to gain the required accuracy. Comparisons between results at established metrology laboratories and the tape-calibration system at the HIF indicate that the HIF system is adequate for calibration of USGS electric tapes, and a program has been established to retrieve all USGS field electric water-level tapes for evaluation and calibration. Results of this ongoing evaluation and calibration of in-use USGS electric tapes will be presented.
Graeme Bowles, P.G.
Groundwater analysts can add significant analytical power to their portfolio of evaluation techniques, by employing underused and underappreciated techniques from other technical disciplines. Examples of these techniques will be presented, from groundwater projects that have included collection of time-varying data. This reflects the proliferation of in-situ data recorders deployed in observation wells, for measuring water levels and other parameters. In addition, time-varying data from SCADA systems and similar operational platforms continues to play an important role on many groundwater projects, especially those involving the management of water supply well fields and hazardous waste remediation pumping and injection wells. The underused and underappreciated techniques address a range of analysis objectives, and generally provide supplementary results, complementing mainline methods used by groundwater professionals.
Graphing of single and double mass curves – a technique used widely in surface water hydrology and meteorology – helps analysts discern trends that may be very difficult to perceive, as well as facilitating identification of changes in trends and comparisons between conditions at different monitoring points. Examples will demonstrate the use of single and double mass curves for characterization of remediation system pipe clogging, and for assuring maintenance of wetland hydroperiod.
Signal-processing techniques have been developed extensively within technical disciplines such as electrical engineering. One of these techniques, called Fast Fourier Transform (FFT), provides frequencies of multiple signals within time-series of data. Examples of groundwater-related FFT applications include identification of coastal/earth tide impacts on water levels versus signals from diurnal, every-other-day, and weekly irrigation pumping wells. Such efforts can be extended to help identify specific pumping wells potentially affecting plume capture and aquifer restoration efforts.
Enhancements of these techniques, for increasing usefulness on groundwater-related projects, will be highlighted. In addition, other similar techniques will be cited, and recommendations provided for wider application of underused methods by groundwater professionals.
Xin Song, Professor
The effect of different environmental conditions, including nZVI dosage, temperature, pH and dissolved oxygen concentration in water, were investigated. It was found that the defluorination ratio increased significantly with the increase of nZVI dosage. At the dosage of 11.2g/L, the PFOS defluorination ratio reached nearly 100%, demonstrating a complete PFOS decomposition. The defluorination ratio increased from 60% to nearly 100% with the temperature increasing from 27 °C to 40 °C. However, the defluorination ratio decreased significantly if the solution pH was adjusted from 7.5 to 3 using hydrochloric acid. Comparative experiments showed that dissolved oxygen in water would affect the reductive defluorination of PFOS. In addition, kinetic experiments were conducted to investigate the reaction rate. To investigate the PFOS degradation mechanisms, further work to identify the degradation products are being carried out.
The Quest for Relevant Baseline Groundwater Data in the Context of South Africa's Potential Energy Futures
Audrey Levine, Ph.D., P.E., BCEE
In South Africa, there is increasing interest in improving energy reliability and security through developing unconventional energy sources. However, the decision process surrounding South Africa's energy futures requires a robust understanding of the water-energy nexus, especially under changing climatic conditions, recurring droughts, population growth, and increasing urbanization. The region targeted for energy development has historically supported rural populations and farming. This paper will provide an overview of energy/groundwater interdependencies in South Africa, discuss current and emerging approaches for developing baseline data, and provide practical insights from field investigations. The presentation will highlight the unique opportunity to leverage the global knowledge base related to unconventional energy development towards developing relevant, useful, and useable baseline data. The capacity to serve as a test-bed for new technologies and sensors will also be explored.
Trevor Osorno, Graduate Student
James Weaver, Ph D
Organic Contaminants in a tourist area: unexpected presence in the groundwater of the Yucatan Peninsula
Rosa Leal-Bautista, Ph.D.
We are concerned that POP’s are starting to show up not only in areas where the predominant activity is agricultura, but also, in new tourist developments. Additional care will be required to ensure that we can meet appropiate drinking water standards in this región.
KEY WORDS Yucatan Peninsula Mexico, Organic compounds, karst
Testing the Ideas of Walter White: An Estimation of Riparian Evapotranspiration Using Groundwater Upwelling
Kimberly M. Slinski, MSc, PE
Sasmita Sahoo, Ph.D.
John Hoaglund, Ph.D. (geology)
Chelsea Jefferson, LG, LHG
John Jansen, P.G., P.Gp., Ph.D.
Road salt is the major culprit. Depending on the aquifer, about 25% to 65% of the road salt applied ends up in groundwater. Recent efforts have reduced salt application rates to some degree, but public expectations of snow free roads has resulted in total salt loading continuing to increase. Decades of past heavy salt use will result in rising chloride and sodium levels for decades in many aquifers.
The keys to managing this problem are monitoring, prevention, and mitigation. We present case histories from New Hampshire, New York, and Wisconsin where chloride impacts in shallow wells were tracked to road salt application, the lateral and vertical extent of contamination were defined by monitoring wells or geophysical methods, future salt levels were predicted, and mitigation methods have been proposed and implemented.
We present a salt budget that was calculated for a capture zone of a well field in Central Wisconsin that has a history of elevated sodium and chloride levels. We compared the salt loading in the capture zones to recharge and residence time of the groundwater as a simple way to estimate future salt levels. In this example the aquifer had short residence times and sodium and chloride levels were approaching steady state. Several simple steps such as diverting snow melt from parking lots away from infiltration basins were successful in reducing sodium and chloride levels at specific wells.
Seth Kellogg, PG
John Wilson, Ph.D
An Integrated Approach for Deducing Degradation Pathways at Sites Contaminated with Chlorinated Ethylenes
Todd H. Wiedemeier
There is no clear guidance on how to choose between MNA, biostimulation, and bioaugmentation, a shortcoming that causes unnecessary expenses and potentially detrimental environmental impacts. A systematic framework was developed under a project sponsored by ESTCP. This framework represents an extension of the 1998 USEPA Technical Protocol for Evaluating the Natural Attenuation of Chlorinated Solvents and (i) incorporates quantitative information of Dehalococcoides mccartyi biomarker genes, (ii) uses Compound-Specific Isotope Analysis (CSIA) results, (iii) considers the contribution of abiotic transformation of contaminants, and (iv) recognizes that natural attenuation is an important component of integrated remediation strategies. This approach allows identification of existing degradation mechanisms and integrates groundwater geochemical and contaminant data with quantitative real-time PCR and CSIA information, along with the current understanding of biological and abiotic degradation mechanisms, to deduce degradation pathways.
Groundwater Remediation of Radionuclides Using a Novel Permeable Reactive Barrier: Laboratory and Field Studies
Using a novel design and installation, the effectiveness of three different permeable reactive materials was investigated: zero-valent iron, phosphate material, and sulphate-reducing bacteria. To evaluate reactivity of the materials, batch and column experiments were conducted in the Kiev Polytechnic University laboratory using Zhovty Vody site groundwater. Reaction rates, residence time, and comparison with site-specific clean-up standards were determined. In the PRB installation, three separate rows of cylinders were filled with different permeable reactive materials, and groundwater sampling was conducted within and around the PRB. Key sampling parameters included field parameters, inorganic analytes, and contaminants of concern (radionuclides and heavy metals). Groundwater levels were also measured periodically throughout the study. Results of the study demonstrate the effectiveness of zero-valent iron and a mixture of sewage sludge, bone meal, sawdust, and water for remediating uranium contaminated groundwater when utilized in a PRB with this design.
Meeting the Critical Deadline While Implementing a Trio of Multi-Million Dollar Remedies: Collaboration Required
Remediation included multiple excavations, installation of a directed groundwater recirculation system over 12 acres of property, and the installation of a large electrical resistivity heating system. The team formed to implement the remediation included three consulting firms and input from the property purchaser’s consultant. Without collaboration, the objectives could not have been successfully implemented within the timeframe.
Construction occurred simultaneously during the Summer/Fall of 2014. At times, more than 100 construction personnel were on-site. The presentation will discuss the logistics of implementing the large remediation effort in a short timeframe. The process began with analysis of federal, state, and city permits and timing for completion of each. The permitting process was initiated while the remedial strategy was finalized. Areas of the site required two, or sometimes three, remediation activities to be implemented. Prior to construction, conflicts were identified and alternate solutions presented to streamline project implementation.
A site-wide construction manager was employed, while each remedial discipline also had an on-site construction manager. Technical teams for each remedial group worked to communicate scope, schedule, and project impacts. Weather delays, contractor coordination, and multi-trade union cooperation required schedule change and planning to meet the timeframe. Sequencing drawings were used to manage contractor progress, giving a visual representation of work, loading, and staging areas, and traffic patterns during construction activities. A comprehensive health and safety program with on-site supervision resulted in zero lost time incidents with over 30,000 man-hours worked.
Three independent, conservative tracers were injected at three separate site locations into two different hydraulic formations. Downgradient concentrations were monitored for one year to develop breakthrough curves. Hydraulic heads and chemistry were monitored site-wide to collect traditional calibration data. The tracer data indicated the presence of a previously uncharacterized, localized preferential flow pathway through highly weathered bedrock.
MODFLOW and MT3DMS were used to simulate the hydraulics and chemical transport for the site and the preferential flow pathway. The three conservative tracers, along with chemical data for the five site constituents, provided eight independent datasets used to calibrate the geometric and hydrogeologic parameters of the preferential flow pathway. One constituent was the daughter product of another, which provided another check on the modeled decay rates. Particle tracking was used to calculate a site-specific dispersivity value.
Using the tracer test data to calibrate both models yielded more robust and accurate calibrations than could have been achieved using only traditional data metrics. Good breakthrough curve matches were achieved at a large number of downgradient wells for all eight solute transport models. The geometry of the preferential pathway conformed well with estimates of weathered bedrock thickness from boring logs, and the site-wide normalized root mean square error for hydraulic heads was less than 5% for all modeled times.
David S. Lipson, Ph.D., PG
Tess Russo, Ph.D.
Extended Learning Session: Distributed Temperature Sensing (DTS) for Investigating Water Movement and Emergence Locations
Dawn Gibas, PhD, PSS (MN), CPSS
Gold King Mine Interim Water Treatment Plant: Design Considerations, Construction and Lessons Learned
Jason R. House, CG, PG
Evaluation of excluding deficient models on multi-model analyses using AICc and KIC information criteria
Buvana Ramaswamy, P.G.
In addition to the adverse impact on irrigated agriculture, waterlogging and salinization are also causing extensive damage to Pharaonic temples built in the Nile River valley. The antiquities are threatened by the increase in salinity of the groundwater contacting the foundation. To protect these antiquities from further deterioration, the Government of Egypt, through its implementing agency, the National Organization for Potable Water and Sanitary Drainage; the owner of the antiquities, the Ministry of Antiquities; and the United States Agency for International Development (USAID) have undertaken projects to lower the groundwater levels at antiquity sites.
At the 2013 NGWA Summit conference in San Antonio, Texas, CDM Smith presented the hydrogeological analysis and 3-dimentional DYNFLOW groundwater modeling that was conducted to support the design of a dewatering system in Edfu, Egypt. Dewatering systems have now been constructed in Luxor and Edfu based on the groundwater modeling for the sites. These completed projects were recently recognized with a 2015 NGWA Outstanding Project Award. Currently, models are being developed for additional sites in Alexandria and Kom Ombo. This abstract proposes to provide a project update based on the new modeling and operations data from the constructed dewatering systems.
Going with the Flow: Federal Funding Facilitates Progress for the U.S. National Ground-Water Monitoring Network
David R. Wunsch, Ph.D., PG
The NGWMN is a collaborative effort among federal, tribal, state, nongovernmental organizations; academia; and private industry volunteers. A brief progress report on NGWMN implementation will be presented, highlighting the commitment, coordination, and communication efforts of stakeholders. We will also present examples how participants are cooperatively leveraging federal support for the NGWMN, with guidance from the Subcommittee on Ground Water (SOGW), under the federal Advisory Committee on Water Information (ACWI). We will focus on: (1) adding new data providers, which is a specific high-priority goal for FY2016; (2) helping maintain and enhance participation of states already in the NGWMN; (3) collaboration between USEPA Regional Laboratories and data providers for testing water quality samples; (4) discussions with other federal agencies that maintain monitoring networks whose objectives and designs align with the NGWMN; and (5) initiating discussions with Tribal authorities, regional water districts, and other non-state data providers.
The progress report will include a summary of data providers as of the date of this presentation, along with anticipated progress for the remainder of FY2016 and FY2017, and future directions for the NGWMN. Details of these aspects of the NGWMN will be provided separately.
This presentation describes the progress of the Network growth to date. A federal appropriation to implement the Network became available in December 2014. Efforts are in place to enlist new data providers and add new sites to the Network. The U.S. Geological Survey (USGS) provided funds to several new data providers in 2015 through cooperative agreements. A solicitation in late 2015 will announce the availability of competitive awards for NGWMN data providers in 2016. A NGWMN Program Board will be established to work with the USGS and SOGW to assist in evaluation of proposals for the competitive awards for the Network. Concurrently, the NGWMN is working with USGS Water Science Centers to add appropriate water-level and water-quality sites to the Network. Adding sites from existing data providers like the USGS can occur quickly. However, adding sites to the Network from new data providers may take up to a year, because sites must be evaluated and communications must be established between various data systems. After the cooperative agreements are completed in 2016, the USGS, SOGW, and NGWMN Program Board can reevaluate the network based on the growth expected over the 2016-17 and then determine the next steps to develop the Network.
South Platte River Groundwater Monitoring Network: Providing Data to Benefit Water Supply Management and the Public
Kevin C. Donegan
The existing network of 115 wells will be expanded to include additional wells measured by DWR along with wells in other monitoring networks operated by cooperating entities. Ideally, wells to be added to the network will have long and uninterrupted periods of record, be located in areas that exhibit long-term trends resulting from human activities as well as short-term responses to those activities, and in areas relatively free of land use, surface-water diversion or artificial recharge.
The purpose of the monitoring network is to provide accurate groundwater-level data to be used in scientific investigations, to increase the public’s understanding and access to groundwater data, and to assist in water use and supply planning. The data identify ambient groundwater conditions and provide for evaluation of the effects of natural and anthropogenic stresses, including climate-related stresses to the aquifer. The South Platte River and its alluvial aquifer play critical roles in the domestic, agricultural, industrial and recreational water-supply businesses of Colorado. An effective and efficient groundwater monitoring program will be an essential component for improved water-resource management of the South Platte River alluvial aquifer.
Joseph Fillingham, Ph.D.
A. Scott Andres
DGS measures water levels as part of routine programs and special projects in 123 wells in two principal aquifers—North Atlantic Coastal Plain aquifer system and Piedmont and Blue Ridge Crystalline Rocks—and 13 major and local aquifers. An additional 50 wells operated by others have been evaluated for the network. More than 20 sites have nested monitoring wells completed in multiple aquifers to allow calculation of the potential for vertical flow between aquifers. Over 100 monitoring wells have 10 or more years of record. All of these wells have known construction details and nearly all have lithologic and downhole geophysical logs.
The DGS makes extensive use of automated water-level and salinity monitoring instruments to efficiently use limited resources, shorten the time needed to characterize the effects of pumping, and identify near real-time responses to climate and weather. Temperature and salinity data collected by these instruments will be added to the NGWMN water quality (WQ) network. The DGS has a long history with database systems. Starting with water-related schema and data vocabulary modeled after USGS WATSTORE in the 1980s, the system now manages data and metadata on lithologic and geophysical logs, rock and sediment samples, and distributes that data through web services in JSON and XML formats for consumption by the NGWMN.
Karl C. Wozniak, MS, RG
In 2015, OWRD began participation in the U.S. Geological Survey’s National Ground-Water Monitoring Network. The principal goal of the network is to provide ready access to data from a set of selective wells in existing observation networks that reflect conditions in major aquifers of the nation. In Oregon, this will be accomplished by reviewing existing networks and selecting high-quality, long-term observation wells that best reflect seasonal and long-term water-level trends in the principal aquifers of the state. A review of the goals and progress of this project will be presented.
Eric Chiang, Ph.D.
To put both the public and local area datasets at the fingertips of investigators, we created the HydroDaVE (Hydrologic Database and Visual Explanations) managed service platform to store and serve local area data and combine them on the fly with data from public data portals.
HydroDaVE consists of three major components: (1) HydroDaVE Server with established web services to serve hydrologic, hydrogeologic, and climatic data that are stored in SQL databases; (2) HydroDaVE Manager (HDM) to remotely manage datasets on the HydroDaVE Server; and (3) HydroDaVE Explorer (HDX), a cloud-connected application with an intuitive map-based interface to visualize and analyze the data (e.g., multiple time-series charts, Piper and Stiff diagrams, geological cross-sections), and to create reports. Both HDM and HDX communicate with the HydroDaVE Server via the web services, which in turn interact with the backend SQL databases.
In addition to the localized data stored on the HydroDaVE Server, HDX can concurrently visualize time series data from the USGS Water Services and the Water Quality Portal of the NWQMC. Moreover, HDX visualizes a great number of gridded climatic datasets, including precipitation, daily minimum and maximum temperature from PRISM (OSU), NEXRAD (NWS), and CMIP3/CMIP5 (IPCC).
HydroDaVE is implemented at watershed-scale and provides integration of a variety of resource data. HydroDaVE is used by government agencies to manage their data and perform complex calculations. This paper provides an overview of the HydroDaVE design and examples of how HydroDaVE has been implemented in Southern California and subsequently used to design monitoring programs, resolve disputes regarding sources of contamination, and a groundwater model application.
Sonya Cadle, P.G.
Thousands of transducer data sets collected during aquifer testing and long-term groundwater monitoring were reviewed to distill key lessons learned that can be applied to any site. When selecting a transducer, consideration must be given to factors such as the goal of the data collection effort, site-specific factors such as lithology and well completions, and the software interface of the instrument. Transducer programming, installation, and download must be planned in a fashion that makes successful data collection as easy and convenient as feasible, and the field staff should be trained to recognize and mitigate common problems they might encounter. Careful documentation is critical during the field effort. When problematic data are collected, the field documentation becomes a vital tool to successfully analyze the data despite its problems. A number of potentially catastrophic problems can be fixed during analysis if good field documentation is available.
Use of the National Ground-Water Monitoring Network to Evaluate Selected Transboundary Aquifer Systems
William L. Cunningham
The power of this capability is demonstrated by analyzing water-level data from three transboundary aquifer systems. First, water-level declines in the Lower Tertiary aquifer system (Montana/North Dakota/South Dakota) are presented. There are increasing demands on the aquifer system to support the water use necessary for increased energy production. Second, water-level declines in the Rio Grande aquifer system (New Mexico/Texas) are evaluated. Competing demands among these states and Mexico have resulted in water-level declines and subsequent lawsuits. Analysis of these data illustrates that the NGWMN provides a single, consistent dataset from which to evaluate the status of the nation’s aquifers and shared interstate groundwater resources. Because the NGWNMN and Canada’s Groundwater Information System adhere to international data-exchange standards, these same comparisons can be done across the U.S./Canada border. Analysis of selected transboundary aquifers between the United States and Canada also will be presented.
George Roadcap, Dr.
A numerical assessment of large screened monitoring wells on groundwater flow fields and solute distribution
Katelyn Kane, MS geology student
The state of Quintana Roo, Mexico on the Yucatan Peninsula is economically dependent on the tourism industry. This study focuses on an assessment of ten locations where direct access to the groundwater is available. Water samples are collected and tested for contaminants thought to be attributable to tourism. The goal of the study is to determine the main threats to public health.
The sites are tested for environmental constituents along with nutrients and various metals concentrations. In laboratory Total Coliform and E.coli fecal bacteria are tested for as a most probable number method and antibiotic presence/ absence tests are performed. The oxygen and hydrogen isotope values were also analyzed. DNA samples from each site were sent out for sequencing. Samples were collected February, April, and June shortly after optimal times of tourist occupancy. Currently the plan is to take one last sample collection during the low tourist season of October. Initial results have shown high amounts of Total Coliform and E.coli fecal bacteria. The nutrient levels and metals are in low concentrations. The antibiotic tests thus far have produced negative results. The current findings of this study suggest that the primary contaminants are the bacteria.
Water Quality Sites and Data Management of Wells and Springs in Utah for the National Ground-Water Monitoring Network
Janae Wallace, M.S.
Our site selection criteria follows guidelines of the Framework Document (SOGW); the primary site selection criteria are accessibility and representativeness of aquifers of interest. Most sites are designated for trend monitoring. The priority of our network is to characterize the water quality of key aquifers in Utah. To ensure high accessibility, most of the wells in our network are regularly pumped and privately owned. Public supply sources are only included if it is the only representative, accessible well in the area or sampled infrequently for limited chemistry (i.e., only NO3 every few years), and only if the location is known and allowed to be disclosed. We chose wells with sufficient aquifer information to ensure they are representative of the aquifer of interest. We sample about 35 springs (smaller springs in mountain blocks/fronts to large regional springs). Selected springs are accessible sampling points that represent major aquifer chemistry with no nearby well; large springs that represent the integrated aquifer chemistry for an entire drainage basin; or springs in mountain areas that represent chemistry of waters recharging the adjacent aquifers.
We are cooperating with the USGS to establish a connection between our network and the NGWMN, and providing the NGWMN with selected sites and related quality controlled data. We are currently establishing a database for our network to facilitate entry and integration of data to the NGWMN portal.
David S. Lipson, Ph.D., PG
Capping and Remedial Extraction of Groundwater in a Shallow Marine Shoreline Sequence at a Former MGP Site in Florida
Steven Sagstad, RG
Published hydraulic conductivity parameters for the three zones were unavailable for the three zones. Therefore aquifer testing of each sand zone was performed to estimate the hydraulic parameters for capture design. Based on aquifer test data collected from an array of observation wells, a transmissivity of 287 feet2/day (hydraulic conductivity of 31.8 feet/day) and a transmissivity of 464 feet2/day (hydraulic conductivity of 77.3 feet/day) were calculated for the intermediate and deep zones, respectively. The deep zone was determined to be hydraulically separated from the overlying layers, whereas the shallow zone appears hydraulically connected to the intermediate sand zone
Radius of capture analyses demonstrated that the extraction wells will contain the contaminant plumes for all zones. A pumping rate of 2-3 gpm for the intermediate zone extraction well and a pumping rate of 5-6 gpm for the deep zone well should be sufficient to contain the plumes on the on-site and off-site. The extracted groundwater is pre-treated with an oil/water separator, permitted and discharged into the local POTW, and the system is operated using PLC, transducers, pump controllers, and supporting equipment. The remedial system is currently operational and the site will be capped to limit recharge and further migration of contaminants
Joe Ricker, PE
Groundwater plume analytics refers to the use of innovative evaluation techniques and methods to reliably and effectively communicate meaningful patterns in environmental data. Analytics relies primarily on graphical displays to communicate insight. Various case studies of remediation sites will be presented which highlight the use of plume analytics.
The plume analytics tools which will be presented include applications based on the Ricker Method® for plume stability analysis1. A plume stability evaluation allows the stakeholder to assess whether a contaminant plume is stable, decreasing, or increasing for a variety of metrics (i.e., area, concentration, mass, center of mass, and spread of mass). This allows better evaluation of remediation effectiveness, whether additional remedial action is necessary, if risk-based closure of a site is applicable, or whether natural attenuation processes may be occurring at a site. Outputs from the Ricker Method can be used as a basis for primary analysis and other plume diagnostic tools that allow the user to further evaluate and communicate groundwater plume dynamics. Examples will be presented that show evolving spatial differences (animated time sequence) within a groundwater plume resulting from remediation systems. Spatial differences are presented on both a magnitude basis and percent change basis.
Groundwater plume analytics tools have been used successfully to evaluate remediation effectiveness, demonstrate plume stability, cease operation of remediation systems, identify commingled plumes, identify unrealized source areas, and provide additional lines of evidence for natural attenuation.
New Dimensions in Groundwater Investigations: Using 3D Visualization Tools to Support Adaptive Strategies
A water treatment plant (WTP) using conventional air stripping technology and carbon polishing to remove chlorinated volatile organic compounds (CVOCs) before discharging the treated groundwater was in operation for over 12 years. The WTP was efficient at treating CVOCs to regulatory levels. However, rising operation and maintenance (O&M) costs, e.g., chemicals, electricity, and labor, necessitated an alternative for treating groundwater contaminated with CVOCs. The alternative had to remove CVOCs to below detection limits (BDL) for incorporation into the Monitored Natural Attenuation (MNA) remedy component, decrease O&M costs, and meet regulatory approval.
A series of field pilot tests, based on air stripping/carbon polishing technology, were designed to evaluate a Passive Aeration System (PAS) to demonstrate that CVOCs could be successfully removed to BDL. Based on the successful pilot tests, a full-scale test was implemented and demonstrated that the PAS could consistently remove CVOCS to BDL at flows up to 10 gallons per minute
Removal efficiencies and CVOC speciation from the pilot tests indicated that the PAS technology was a viable alternative to the conventional WTP. Analytical results from the full-scale test showed consistent analytical results of CVOCS that were BDL. The PAS was approved by the U.S. EPA and the Oklahoma Department of Environmental Quality as a permanent remedy modification to replace the conventional WTP.
The electricity savings alone using the PAS amount to more than $20,000 per year. The PAS also employs air stripping and polishing steps but utilizes the sun and wind to remove the CVOCs without electricity or chemicals and with minimal O&M costs.
Daniel Abrams, Dr.
The more severe drawdown in northeastern Illinois has resulted in local areas where heads have fallen below the top of the sandstone, known as desaturation. Desaturation of a sandstone aquifer can create a number of water quality and quantity concerns. The uppermost sandstone, the St. Peter, was observed to be partially desaturated in the areas of greatest pumping, even at wells which were cycled off. Simulations from a groundwater flow model indicate that the risk of desaturation will become more severe with increased future withdrawals.
Despite the relatively small demand for water throughout much of central Illinois, heads have been declining since predevelopment, likely due to the shale overlying the sandstone. This shale serves as an aquitard, minimizing vertical infiltration of groundwater to the sandstone. Sustained drawdown in this region could potentially induce flow from the southern half of the state, where water in the sandstone is highly saline and not suitable as a drinking water supply.
Keith J. Halford, Ph.D.
Jennifer S. Stanton
The U.S. Geological Survey is reassessing the alternative water supply potential of significant brackish groundwater resources. Preliminary results indicate that almost one third (2.2 million km2) of the continental United States is underlain by brackish groundwater (dissolved-solids concentration between 1,000 and 10,000 mg/L) within the uppermost 3,000 ft of the land surface. This evaluation is likely an underestimate of the total resource because available data for mapping the distribution of brackish groundwater are scarce in some areas, especially for depths greater than 500 ft below land surface where brackish groundwater is more likely to occur. Most of the known brackish groundwater is within in the Western Mid-Continent region. Other significant reserves of brackish groundwater largely are found in the Atlantic and Gulf Coastal Plain, Eastern Mid-Continent, and Southwest Basins regions. The ability of brackish aquifers to produce at least 100 gal/min of water was greatest in the Southwest Basins (80 percent of wells) and least in the Western Mid-Continent region (8 percent of wells).
Since 2007, the Virginia Department of Environmental Quality has been actively implementing goals developed through strategic planning to reduce current use, promote greater water conservation measures, increase hydrogeologic understanding and modeling capabilities that assist or promote innovative ways to manage groundwater in Virginia.
To help meet these objectives the following actions have been taken since 2007:
Conducted a Peer Review
Expanded internal resources and associated budgets for characterization efforts through legislative amendments
Passed revised regulations and expanded a Groundwater Management Area
Revised guidance documents and policies
Migrated the new Virginia Coastal Plain and Eastern Shore Models into use and then integrated with new geo-referenced content management system as VAHydro
As a result of those initial actions VADEQ has now embarked on the next step, the Virginia Coastal Plain Groundwater Initiative. The initiative includes modeling activities to evaluate the optimization of proposed reductions, an investigation into the economic impacts associated with those proposed reductions and a 2015 legislative action resulting in the creation of the Eastern Virginia Groundwater Management Advisory Committee. The Committee has been tasked with examining options for developing long-term alternative water sources and management structures along with other actions that may enhance the effectiveness of groundwater management.
Tess Russo, Ph.D.
Basin Wide Groundwater Model of the Rialto-Colton Basin for the Source Area OU Remedy for the RFF Superfund Site
The RCB is an alluvial basin located in southern California that is bounded by faults and bedrock outcroppings. The majority of water inflows to the RCB are in the subsurface across fault boundaries. The majority of outflows consist of groundwater extractions for municipal water supply. All groundwater extraction in the RCB, including that of the SAOU, is subject to operational constraints imposed by the 1961 RCB Decree as well as the capacity of the water treatment and supply infrastructure. Given these considerations and the project objective, it was necessary to begin model development with quarterly water balance of the RCB. The water balance components were compiled for 42 years (1970-2011) using extensive data collected from various water purveyors. The RCB water balance builds upon previous models of the RCB, as well as neighboring basins. However, it was also necessary to develop new parameterizations due to the complex relationship between inflows and stratigraphy in the RCB.
Based on predictive simulations, one extraction well was located such that a high degree of hydraulic capture was predicted. The basin-wide model development approach, with its emphasis on a reasonable water balance, extensive calibration, and thorough examination of potential extraction options made it possible to optimize SAOU remedy pumping in the near term as well as anticipate potential future pumping requirements.
As more than 80,000,000 Mexicans depend on groundwater as their sole source of water, mapping potential infiltration/recharge zones is critical for Mexico. We are partnering with UCIA-CICY (a CONACyT Research Center) to develop a GIS-based mehtodology to identify potential Hydrogeologic Reserve Zones. Integrating both tools may allow Mexican policy makers to have a tool that will help with groundwater management in Mexico.
Sharon B. Megdal, Ph.D.
Steven P. Musick, B.S., PG
Amy Rice, Ph.D. Candidate
Joseph Lee, PG
The Gateway website is an invaluable tool for government, industry and financial analysts, scientific researchers, and others who want a simple way to obtain and analyze well level data across the United States.
Benefits of the Gateway for States include a more robust portrait of State activity within a national context, data to view intra- and inter-basin activity in adjoining States, fewer staff hours spent responding to external inquiries, and increase transparency.
Min-Ying Chu, Ph.D., P.E.
The open-loop GSHE system was assumed to use groundwater recirculation to meet all cooling and heating demand. The hydrogeological framework of the study area was based on published literatures and review of more than 60 water wells and borings in the study area. The groundwater flow field and thermal transport was evaluated using the MODFLOW and MT3D modeling tools under different recirculation configurations. To account for the thermal energy interaction between the injection and extraction wells, the injected groundwater temperature was based on time-dependent thermal loading and simulated extracted groundwater temperature. The projected magnitude and pattern of heating and cooling demand were repeated for 12 years to evaluate the long-term system performance.
The system feasibility was assessed using the following criteria: (1) ability to service the peak thermal load, (2) ability to maintain the temperature of extracted groundwater within the range of effective heat exchange, and (3) possible thermal impacts to groundwater receptors as thermal energy migrates away from the site.
Joshua W. Brownlow, PG
A Proposed Approach to Sustainable Groundwater Extraction Based on Surface Water-Groundwater Interaction
Michael Tietze, PG, CEG, CHG
The amount and timing of streamflow depletion depends on pumping rate and duration, well location relative to the stream, aquifer diffusivity, streambed conductance, and vertical flow impedance within the aquifer system. These principles were used to develop proposed groundwater management zones around aquifer-connected streams by simulating extraction from theoretical wells at various depths and distances from the streams, under a range of stream and aquifer conditions. Simulations were carried out using STRMDEPL08, an analytical streamflow-depletion model developed by the USGS, and validated using existing numerical groundwater flow models constructed using the USGS MODFLOW code. Simulated surface water depletion by shallow wells near streams closely mimics applied pumping rates and timing, which supports groundwater management in tandem with surface water as is currently done in California for pumping from a “known and definite channel.” Pumping from greater distance or depth causes an attenuated hydrologic response in both amplitude and time. Groundwater management zones are thus proposed based on distance to the affected stream, depth of the well’s screen interval, and timing and duration of predicted streamflow depletion, considering the amount of seasonal and long-term streamflow depletion that is tolerable under existing ecological and water rights requirements.
Jeffrey J. Frederick, RG, CPG
Groundwater As a Loading Mechanism in Two Tidal Estuaries, Gowanus Canal and Newtown Creek, New York, New York
Shane McDonald, CPG
Jason R. House, CG, PG
Joe C. Yelderman Jr., PhD, PG
Sub-Regional Groundwater Flow Modeling of the Upper Big Blue Basin Using the MODFLOW-OWHM Farm Process
Mario R. Lluria
H2O Talk: Reclaiming Our Water Resources: Breakthroughs in Groundwater Remediation for Today and Tomorrow
Suthan Suthersan, Ph.D., PE
Raymond Johnson, Ph.D.
The Jwaneng and Orapa Mines of Debswana Diamond Company have reached depths of approximately 300 metres (m), and resource evaluations indicate that the pits will extend to depths of approximately 900 to 1,000 m. These depths will be achieved in approximately 35 years, requiring aggressive planning for how water will be managed to optimize pit slopes. Groundwater, surface water, and pore-pressure controls are paramount if stable slopes and safe mining are to be achieved. In the case of both mines, geologic units that constitute the pit slopes are generally of low permeability, dictating that dewatering/depressurisation systems must be implemented expeditiously.
Numerical groundwater flow modelling for both mines demonstrated that pit perimeter dewatering boreholes will be essentially ineffective in achieving depressurisation goals (that are established by stability analyses). Low-permeability geologic materials prevent effective propagation of low pressures within the dewatering borehole. As such, the focus of depressurisation is on in-pit dewatering boreholes along with sub-horizontal drains. Additionally, emphasis is also placed on preventing enhanced recharge from reaching the perimeters of the mines. Natural recharge from precipitation at the mines is low; however, artificial recharge (for example, from leaking pipes at the processing plants, leakage from tailings and slimes storage facilities, and surface-water runoff from nearby waste rock piles) is high and requires engineering intervention measures in order to maintain slope stability as pit depths increase.
Management concepts for addressing depressurisation include under-drainage utilizing tunnels and drains, eliminating enhanced recharge and future disposal areas located farther from planned pit expansions. In addition, surface-water control systems to intercept and direct precipitation runoff away from the pits are an integral part of effective pit groundwater controls.
The depressurisation and water-management techniques listed above require close cooperation and integration between hydrogeologists, geotechnical engineers, mine planners, and, lastly, mine pit operations personnel.
Chad Milligan, PG
The treatment and disposal of native groundwater infiltrating the mine was analyzed using a holistic approach, including an evaluation of the water quality by assessing the chemical and physical characteristics of water, water quantities, water treatment system, geochemistry, and applicable disposal well characteristics. The analysis identified specific minerals that may be precipitating from the concentrate and causing scaling issues within the disposal well, the specific location within the disposal well the scale could be forming, and recommendations to address the scaling issue both through a well stimulation plan and adjustments to the groundwater treatment system design and operation.
Understanding how scale forms can help formulate a plan for treating the well. Temperature and pressure fluctuations can have an impact on solubility coefficients, and can also cause local fluctuations in the equilibrium ion concentration in the solution. Once the seed crystals start growing, the heterogeneous nucleation process may start at surface defects such as joints, seams, or areas with surface roughness. A high degree of turbulence can also start the process of scale deposition, such as restrictions in the well. This presentation will focus on why and where scale forms in a groundwater treatment and disposal system and how to prevent it, which will assist to avoid costly workovers and inefficiencies in chemical dosing.
Seth Kellogg, PG
Dawn Paszkowski, M.Sc.
Groundwater monitoring and flow modeling were completed in support of regulatory approvals and engineering design. The numerical model was developed using MODFLOW-Surfact and was calibrated in stages to available data, including seasonal hydraulic heads, vertical hydraulic head gradients, streamflow and winter low-flow estimates, and volumetric dewatering flowrates. Two distinct approaches were used to represent the underground workings in the model, an active approach using a fracture well and a passive approach using drain boundaries, which helped constrain hydraulic property estimates. Detailed calibration to observed flowrate and hydraulic head response data suggested that the bulk hydrogeological properties of this complex system were well characterized and suitable for further analyses.
The calibrated groundwater flow model was subsequently used to estimate groundwater flow rates to the proposed underground mine and surface water receptors, predict drawdown throughout operations, and simulate recovery of the groundwater system in the closure period for base case and sensitivity scenarios.
Daniel S. Weber, PG
As outlined by standards and guidelines for quantifying mineral resources and reserves, key variables such as brine volume and grade, aquifer geometry, hydrogeologic unit, effective porosity, specific yield, flow rate, and recoverability are used in order to meet the definition of reasonable prospects of economic extraction and to define the mineral resource. Conversion of status from a mineral resource to a mineral reserve requires modifying factors ranging from mining methods, to processing strategies, to environmental, social, and permitting aspects of the project.
Production wells in deeper deposits, or extraction trenches for shallower systems, are generally the mining methods for extraction of brine resources. Hydrogeologic methods are thus critical to evaluating what portion of a defined mineral resource is economically extractable and can in turn be defined as a mineral reserve. Consistent with industry guidelines, we use the technical reporting terms “Drainable” and “Extractable” as factors for evaluating and advancing project status from mineral resource to mineral reserve. These hydrogeologic modifying factors are in part supported using exploration results, aquifer testing, conceptual modeling, and hydrodynamic numerical modeling methods simulating wellfield or trench extraction for mining the lithium-enriched brine.
Because there is sparsely documented information available from deep boreholes in the southern part of the state, information from central and northern Illinois was extrapolated for purposes of evaluating the geologic suitability of selected injection intervals for fluid disposal in the deepest portions of the basin. Exploratory boreholes were drilled for two underground coal operations into or near the Precambrian basement with total depths ranging 12,000-13,000 feet. The wells were completed as partially perforated cased/open hole through the injection interval. Cores taken during initial drilling of the boreholes supported published data that one formation displayed vugs that appeared to be interconnected, but laboratory tests revealed an over-consolidated, low porosity and permeability formation lacking interconnectivity of voids. Furthermore, the most suitable formation is thin or absent in the deeper Basin. This presentation will explore the successes and lessons learned from completion and testing of these deep injection wells and examine future drilling and completion practices within the deeper portion of the Illinois Basin.
Michael Celia, Ph.D.
Aspect Controls on Rock Weathering and Permeability within the Boulder Creek Critical Zone Observatory
Behavior of a Fault Arose By a Water Level Variation and Its Poroelastic Understanding - a Case of a Fault Near Tries -
Hiroshi Ishii, Ph.D.
ISHII Hiroshi and Yasuhiro ASAI,
Tono Research Institute of Earthquake Science (TRIES), Association for the Development of Earthquake Prediction (ADEP).
Tono Research Institute of Earthquake Science (TRIES) has developed a multi-component borehole instruments for continuous observation. The instrument is equipped with stress meters, strain meters, seismometers, tilt meters, magnetometers, and a thermometer, and we can choose the contents of the instrument as we like. At the present time about 15 borehole stations are in operation. The depth of the deepest borehole is 1030 m. There is a fault near our institute. We have investigated a relationship between a variation of underground water and a behavior of the fault by using geophysical data obtained from borehole observations.
Near our observation stations deep boreholes with diameters of 4m and 6.5m are under construction. And depth is about 500m at the present time. During the construction spring water sometimes happens and we analyzed the data caused by this. We also made experiments of water pumping out for a borehole near the stations and analyzed the data caused by this.
The main results obtained are as follows: 1: water level of TGR350 borehole station with 350m depth decreases by the pumping water and the spring water. Data of the strain meters installed at 350m depth indicate right lateral movements of the fault near TRIES. 2: data of the strain meters installed at 350m depth indicate left lateral movements of the fault in case of recovery of water level. 3: strain meters installed at shallower depth (165m) and extensometers installed in sedimentary layer do not indicate such fault movements. 4: we have considered a mechanism explaining the phenomena by using poroelastic understanding.
Combining Geochemisty/Geophysics to Pinpoint Sources of Salinity in the Rio Grande and the Relationship to Faults
For decades scientists have been trying to understand why there is an great increase in salt content from ~40mg/L at the headwaters of the Rio Grande in Colorado to ~1500 mg/L in El Paso, TX. The increased salinity has limited its use as city drinking water and agricultural irrigation water. The saline water causes problems such as increased soil salinity and reduction of crop productivity. This project focuses on pinpointing sources of salinity in the Rio Grande and its relationships to the fault systems within the Mesilla Bolson using a combination of water geochemistry and geophysical data.
Previous studies suggest multi-source contribution of salt to the overall salinity of the Rio Grande. This study has attempted to assess two main sources: 1) natural upwelling of saline groundwater through subsurface faults; and 2) return flows from the agricultural fields after irrigation with Rio Grande water and groundwater. Previous gravity studies have exposed a complex fault network throughout the Mesilla Bolson. This study has combined these datasets with new geophysical investigations to infer groundwater flow paths along the fault systems. Modeling the flow system of the Mesilla Bolson and its relationship to the Rio Grande can expose a potential salt influx from the faults of the Mesilla Bolson. Furthermore, the geochemistry of groundwater samples will be used to distinguish salinity sources from the natural groundwater upwelling and the agricultural return flows to the Rio Grande.
Smart Energy and Water Meter (SEWM): An Innovative Approach Towards Groundwater Monitoring and Management
While there are different methods to measure, control and manage groundwater resources in the World, however most of these methods are facing common issues of typical meters such as sensitivity and vulnerability against suspended particles, air bubbles, pipes’ slope, existence of tap, bend and connections. As such, in this paper, RSA Electronics Co. presents a novel solution, which is an effective management system for monitoring and management of groundwater resources by eliminating these common issues.The core section of this solution is a smart meter, which is called Smart Energy and Water Meter (SEWM). This innovative solution is the result of continues research and development activities, patented in US in the field of measuring electricity, and water includes the following sections:
- The meter (SEWM) which is an active/reactive multi-tariff device, measures and records consumed-energy and relevant parameters required by the energy authorities.
- The SEWM also is capable of measuring and storing the amount of water withdrawal, water flow and other quantitative parameters. The meter indicates water credit, validity of start and expiry date; also, it is capable of reacting based on the client’s demand if user exceeds allowed credit water or credit time is over.
- The collected details of water wells are transferred to the control center via telecommunication infrastructure ; data processing and reporting is performed by Meter Data Management software.
Christopher J. Ruybal
Sustaining Water Supply from Groundwater Resources through Nyabarongo River Bank Infiltration, Kigali City Rwanda
Rani Fouad, Dr.
Joe C. Yelderman Jr., PhD, PG
Melissa Lenczewski, Ph.D.
Four variations of IDEXX SNAP test kits including Tetracycline, New Beta-Lactam, Gentamicin, and Sulfamethazine were used to test for the presence of 8 antibiotics within water. All samples were tested in triplicate. Individual solutions of 1% milk were spiked with each antibiotic and tested in the corresponding SNAP kit at 100ppb to serve as controls. Distilled water was tested in all SNAP kits as a second control. A stock solution of 1000ppb was created for each antibiotic, diluted further in distilled water, and tested at concentrations of 1ppb-100ppb. Each 100ppb spiked distilled water sample was also tested with the three non-corresponding SNAP kits to determine cross reactivity
Preliminary results indicate that tetracycline can be detected in water between the concentrations of 100ppb and 10ppb using the tetracycline IDEXX SNAP test. Below 10ppb tetracycline is not always detectable. Previous research reported positive tetracycline results in surface and ground water. Results from the remaining antibiotics are to be determined. IDEXX SNAP kits are potential quick and cost effective tools to detect antibiotics in the environment.
Assessment of Scaling Potential Associated with Using Desalination Concentrate As Hydraulic Fracturing Fluid
Nima Ghahremani, Doctoral Student
Climate Change and Remediation: Droughts Inhibit Site Characterization and Monitoring of Contaminated Sites
Andrew Nunnery, PhD, PG
This study examines the effects of the recent drought on groundwater monitoring at four sites in Texas and California: two hydrocarbon contaminated sites in south Texas, one hydrocarbon contaminated site in southern California, and one hazardous waste disposal facility in southern California. At the two Texas sites, water level decreases resulted in an approximate loss of up to 30% of the monitoring well network. Conditions were more pronounced at the southern California sites, with water level decreases resulting in up to 55% loss of the monitoring well network. At all four of these sites, the decrease in the water table caused the loss of important spatial and temporal site characterization data. The results of this study highlight the need to consider how short-term and long-term climate change may affect efforts to characterize and remediate contaminated groundwater.
Conditioning geostatistical simulations of a bedrock fluvial aquifer using single well pumping tests
In this study, we introduce an approach to condition geostatistical simulations of the Paskapoo Formation, which is a paleo-fluvial system consisting of sandstone channels embedded in mudstone. The conditioning data consist of two-hour single well pumping tests extracted from the public water well database in Alberta, Canada.
In this approach, lithologic models of an entire watershed are simulated and conditioned with hard lithological data using transition probability geostatistics (TPROGS). Then, a segment of the simulation around a pumping well was used to populate a flow model (FEFLOW) with either sand or mudstone. The values of the hydraulic conductivity and specific storage of sand and mudstone were then adjusted to minimize the difference between simulated and actual pumping test data using the parameter estimation program PEST. If the simulated data do not adequately match the measured data, the lithologic model is updated by locally deforming the lithology distribution using the probability perturbation method (PPM) and the model parameters are again updated with PEST. This procedure is repeated until the simulated and measured data agree within a pre-determined tolerance. The procedure is repeated for each pumping well that has pumping test data.
The method constrains the lithological simulations and provides estimates of hydraulic conductivity and specific storage that are consistent with the pumping test data. Eventually, the simulations will be combined in watershed scale groundwater models
We used a floating chamber to measure CO2 degassing rates in a headwater stream reach at Konza. Temperature contrasts, seen with an infrared camera, between discharging groundwater and the stream, located groundwater seeps. We found that groundwater discharge occurs primarily along the stream bank or in fractured bedrock on the stream bottom. At each seep, we collected water samples for major-ion chemistry, δ13C of CO2, and δ13C of dissolved inorganic carbon (DIC). Because the limestone aquifers crop out in the stream, we also collected groundwater samples from nearby wells completed in those limestones.
We compare stream water and groundwater to assess the changes that occur during groundwater discharge to a headwater stream. Preliminary results show stream water degassing at rates between 1.82 and 58.4 g C m2-day1-. The CO2 fluxes and pCO2 decreased with distance from the seeps (~2 meters). Decreases in fluxes and pCO2 were accompanied by heavier carbon isotopic ratios, with δ13C—CO2 increasing downstream of groundwater seeps. Furthermore, groundwater and stream water chemistry were similar for major anions, major cations, and alkalinity. This study provides additional understanding of groundwater and surface water interactions and evidence of a significant contribution to atmospheric carbon from headwater streams in the region.
Quantifying Potential for Spills at Unconventional Gas Well Sites to Impact the South Platte Aquifer
Yasuhiro Asai, Ph.D.
We have developed a Borehole tiltmeter (Ishii et al., 2002) and installed it at the bottom of two boreholes site (STG100 and STG200) in the Mizunami underground Research Laboratory (MIU) in the Tono region, central Japan, as a part of the research. The Tono region is a relatively stable block of Cretaceous Toki granite uncomformable overlain by Tertiary layers (Mizunami sedimentary formations) with a thickness of approximately 100-200m (King et al, 1999, JGR). The STG100 site is located in the Tertiary layers, and the STG200 site in the Toki granite.
As research advances, the following results were obtained: (1) Amount of tilt-down variation at the STG100 site is approximately 1.7×10－5 radian/yr, and variation for the STG200 site is approximately 1.0×10－5 radian/yr. (2) Direction of observed tilt-down variation at both site are almost south-southeast.
In addition to above observation result, groundwater with volume of 700m3 was generally pumping a day in MIU (Kimata et al, 2015, Engineering).We consider that observed tilt-down variations may be caused by the “source” located in neighboring south-southeastern area of MIU.
Subsidence Following Groundwater Drawdown By Excavating of Deep Shafts in Granite in Mizunami, Japan in 2004-2014
In 2012, we extended the leveling network to a width of 4 x 5 km around the excavating shafts, and we had precise leveling in 2012, 2013, and 2014 at the network. As results, subsidence of 4mm is detected around the shafts, and subsidence areas are enlarged to the southeast and northwest in 2012-2014.
A depth distribution of granite in the area is estimated from aeromagnetic surveying. As results, Two groundwater veins are suggested in NW to SE and NNE to SSW, which is a good consistent with ground subsidence distribution.
As subsidence is only 2mm/year, we hope to repeat precise leveling for few years, and to make clear the groundwater system around the shafts.
Waste Rock Biogeochemical Environments in a Sub-Arctic Climate Above and below a Leaky Thermal Cover
System reliability is affected by well pump-offs driven by mismatch of aquifer supply and the pump/motor size or back pressure from the flow lines size, length or system configuration. Not actively minimizing these pump-offs can increase Capex requirements due to damage from continuous across the line starts. Since many of these wells are remotely located, there is a high operations cost to identify which wells have gone down and to get the correct resources to repair them into the field.
New technology is available to remotely manage these systemic risks associated with a water well supply system. Combining power management equipment with 4th generation SCADA and cloud/server based active management systems produces significant economic benefit from improved water supply reliability and reduced opex and Capex exposures.
Leslie Dumas, P.E., D.WRE
Protecting Your Water Supply and Your Bottom Line: Shifting Costs from Ratepayers to Responsible Parties
Recent lawsuits by some water suppliers have successfully pursued an innovative legal strategy. These new cases do not focus on the end user who last touched the product but on the manufacturer of the product who introduced it into the stream of commerce. These innovative cases include lawsuits by water suppliers against the refiners of gasoline containing MTBE, the manufacturers of other products including PCE (used by dry cleaners), TCE (used by a variety of industrial users), and DBCP, TCP, and Atrazine (used by farmers). This new legal strategy has resulted in hundreds of millions of dollars being paid to water suppliers by manufacturers of products which contaminated water supplies.
This innovative approach to water contamination litigation has important implications for water suppliers, lawyers, regulators, and environmental consultants. This presentation will discuss the legal theories underlying these landmark cases and the status of lawsuits currently pending in jurisdictions around the country. The presentation will also discuss the legal and political responsibilities facing a water supplier whose water supply has been impacted by man-made pollution.