Groundwater Data Adequacy

The Issue

The Issue

Some of the wells completed under the Hydrogeologic Workplan do not provide reliable groundwater quality data. Analysis completed of the impacts of residual drilling fluids on the ability of the groundwater wells in the regional aquifer to provide representative measurements of contaminants.

NMED requested a well rehabilitation plan. Since November 2005 LANL has been developing a groundwater data adequacy plan to ensure capability of providing reliable monitoring data. The plan includes a pilot well redevelopment, a plan for well rehabilitation and replacement, and work to complete the data qualification process. Chemical/hydrology testing/modeling will address some issues raised by EPA.

The Plan

The Plan

LANL will evaluate whether the screens are producing data that are reliable and representative of the intermediate groundwater and regional aquifer. These will be summarized denoting the number of screens that are “good” (i.e., producing reliable data) and number of screens that are potentially impacted by drilling fluids. Of the impacted screens, those that appear to be cleaning up over time and those that are the most problematic will be identified. Then a technical basis for real-time screening of new data for reliability will be determined.

Objectives

Groundwater Objectives

• For each screen, identify water quality data that are/are not reliable or representative
• Use an assessment process of 64 screens in 33 wells that is transparent, reproducible, and robust
• Characterization wells installed for Hydrogeologic Workplan
• Screens in regional aquifer and intermediate perched zones
• Current conditions (snapshot)
• Focused on water chemistry, not physical indicators
• Bentonite drilling mud (12 screens in 9 wells)
• Organic drilling fluids (all 64 screens)

Reports

Groundwater Reports

• Well Screen Analysis Report
• Rehabilitation Plan