Recent and Current Research in Geohazards

Properties of Offshore Sediments and their role in Geohazards

Principal Investigator: Don J. DeGroot

Properties of Offshore Sediments and their role in Geohazards (www.offshoregeohazards.org) – a US National Science Foundation project in collaboration with the International Centre for Geohazards (ICG; www.geohazards.no) hosted at the Norwegian Geotechnical Institute (NGI; www.ngi.no) and the Centre for Offshore Foundation Systems (COFS; www.cofs.uwa.edu.au) hosted at the University of Western Australia

Detection and Delineation of Deicing Materials in an Unconfined Aquifer Via EC Measurements
Researcher: Shawn P. Kelley, advised by Alan J. Lutenegger

A low-cost ground-water prototype detection system was developed for the Massachusetts Highway Department to measure in situ electrical conductivity (EC) of ground water. The system, termed "permanent conductivity points" (PCP), consisted of a number of conductivity cells individually comprised of two-array electrodes that were attached to a rigid pipe. This system acted as a "long conductivity meter" that was permanently installed into the ground and used to measure electrical conductivity at specific points in the aquifer. To assist in delineating ground-water contaminants, low flow ground-water sampling ports (WSP) were placed on the rigid plastic pipe adjacent to the PCP monitoring points. The obtained ground-water samples were analyzed in the laboratory for chemical composition. This system was developed to detect and delineate deicing materials deposited into the ground water in an unconfined sandy roadside aquifer.

The prototype detection system was useful in detecting the presence of deicing materials in an unconfined sandy aquifer and beneficial in delineating the shape and extent of the contaminant plume. The ease of construction, installation, and monitoring made this system beneficial for long-term monitoring of the contaminant plume. The large amount of data, which was quickly obtained in a single vertical profile, made this system very appealing for detecting and delineating contaminants that elevated the ambient ground-water electrical conductivity at the site. The possible cost savings using pcp technology for long-term ground-water monitoring may be quite substantial for geo-environmental engineering consulting firms when considering the installation cost, material cost, and personnel sampling-time needed for standard ground-water monitoring wells. The prototype detection system is a technology with a low cost-high benefit for long-term ground-water quality monitoring.

Iron Content, Dissolved Oxygen, Conductivity, and Flow Rate Distribution of an unconfined, roadside aquifer using Continuous Screened Wells
Researcher: Jennifer R. Tooley, advised by Alan J. Lutenegger

Iron content, Dissolved oxygen, conductivity, and flow rate for an unconfined, roadside aquifer are being investigated in Plymouth, MA. The project site is located along State Route 25, just north of the Bourne Bridge, where non-chloride deicing agents are used to protect nearby cranberry bogs. The research site currently has over 100 observation wells installed to monitor groundwater properites.

For this research five continuous screened wells were installed along two site cross sections to observe dissolved oxygen, conductivity, and flow rate changes for a specific location at various depths. At the time of well installation soil samples were recovered for iron analysis.

The focus of this research is to determine the iron content and distribution of iron in the soils at the site and to identify any correlations between iron levels and dissolved oxygen levels. Seasonal effects on dissolved oxygen, conductivity, and flow rate are also being investigated as well as the effectiveness of using dissolved oxygen and conductivity measurements from continuous screened wells to describe characteristics of an aquifer that has a flow rate of 1-3 feet per day.

For more information about past research projects click here