Formatted Title
Improved Resolution in Sediment Characterization Data for Design via Vibracore Sediment Acquisition Monitoring Methods
Background/Objectives
Conventional methods for processing sediment cores requires assumptions based on total sediment recovered compared to the total distance the sampler is driven into the sediment. Two assumptions are typically made: 1. The loss is evenly distributed across the core, or 2. The loss occurred from the bottom of the core—both of which introduce opportunity for wide ranging estimation errors when considering in situ depth of contamination. More accurate vertical data for sediment intervals that represents true in situ conditions, both physically and chemically, improves sediment remediation design and managing sediment volumes to be dredged.
Approach/Activities
Vibracore sediment acquisition monitoring (V-SAM) uses instrumentation to measure sediment acquisition within the core sampler and penetration of the core tube relative to mudline concurrently. For each core, the penetration and acquisition values are recorded and plotted on an acquisition curve in real time then provided to the core processing team to establish the in-situ sampling depths, corresponding to recovered core length, for use during logging and sampling. Techniques were developed and refined over three projects and more than 140 cores have been logged and sampled based on in-situ intervals using V-SAM measurements.
Results/Lessons Learned
We will present techniques employed to using V-SAM to reduce the length over which uncertainty and present examples of how much difference in volume and cost of remediation this uncertainty in depth of contamination may result in.