2016 NGWA Groundwater Summit

Adding Analytical Power By Applying Underused and Unappreciated Techniques

Tuesday, April 26, 2016: 11:40 a.m.
Platte River Room (The Westin Denver Downtown)
Graeme Bowles, P.G. , Tetra Tech, Inc., Tampa, FL
Robert Schreiber, PE, BCEE, D.WRE , Water Resources, CDM Smith
Stefania Hurtado , Civil Engineering, Northeastern University, Boston, MA
Sonya Cadle, P.G. , Tetra Tech, Louisville, CO

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.

Graeme Bowles, P.G., Tetra Tech, Inc., Tampa, FL
Non-presenting co-author - to be provided

Robert Schreiber, PE, BCEE, D.WRE, Water Resources, CDM Smith
Mr. Schreiber is a registered professional engineer with over 44 years of experience in water resource planning and computerized engineering analysis. He graduated from MIT’s Civil Engineering Department where he focused on groundwater hydrology and water resource systems analysis. He is a senior technical leader specializing in modeling of groundwater flow and contaminant fate and transport, and serves as a company-wide resource at CDM Smith. He has served on the Federal Advisory Committee on Water Information as ASCE’s representative to and co-chair of its Subcommittee on Ground Water, focusing on implementation of a National Ground Water Monitoring Network. For NGWA, Mr. Schreiber has served as Chair of the Scientists and Engineers Division Board of Directors and on the NGWA Board of Directors.

Stefania Hurtado, Civil Engineering, Northeastern University, Boston, MA
Non-presenting co-author - To be provided

Sonya Cadle, P.G., Tetra Tech, Louisville, CO
Sonya Cadle has 15 years of professional experience in environmental geology and hydrogeology. Ms. Cadle's typical duties include groundwater flow and contaminant transport modeling, aquifer testing and analysis, and long-term monitoring network design and management. She is often involved in characterizing sites with complex hydrogeological environments and uses various software tools to assess site conditions, remedial options, water resource availability, and dewatering needs.