Chris Wenczel, P.G.
ERM Consulting & Engineering, Inc.
Many environmental investigation and remediation sites are located near tidally affected freshwater, estuarine, and marine surface water bodies. Where present, tidal influence in nearshore aquifers is caused by a pressure wave propagation inland from the surface water body resulting in physical dewatering of the aquifer grains in unconfined aquifers and/or corresponding fluctuations in potentiometric surface heads in semi-confined or confined aquifers.
Understanding the interaction of surface water body tidal fluctuations (sinusoidal fluctuations on surface water body elevations) on the nearshore groundwater environment is necessary to accurately assess vertical and horizontal hydraulic gradients used to determine corresponding horizontal and vertical groundwater flow directions, and to develop meaningful conceptual site models. Mischaracterization of groundwater gradients and resultant misinterpreted flow directions using standard mapping methods can lead to incorrect conceptual site models, inaccurate assessment of chemical fate and transport, and flawed remedial action design requirements.
Tidal influence studies can be easily implemented using wells screened in nearshore tidally influenced aquifers to filter groundwater level data, and calculate mean hydraulic heads in each well and calculate vertical and horizontal gradients across the aquifer(s). Application of resultant interpreted net flow directions can lead to more accurate conceptual site models, assessment of chemical fate and transport, and more effective remedial action designs and/or monitored natural attenuation conclusions.
Mr. Wenczel will present information on the above abstract using several case studies.
Come join us for an evening of professional camaraderie, networking, food, refreshments and fun!!