Reevaluation of Ground-Water Quality in the Piedmont Region of Baltimore County, Maryland

WRD PROJECT #: MD153
PROJECT CHIEF: Bolton, David
BEGIN DATE: 01-July-2000
END DATE: 30-Sept-2001

Customers currently supporting the project:

Maryland Geological Survey

Problem

A study of the ground-water quality in the Piedmont region of Baltimore County, Maryland was conducted between 1994 and 1996 in a cooperative project between the Baltimore County Department of Environmental Protection Resource Management (DEPRM), the Maryland Geological Survey (MGS), and the U.S. Geological Survey (USGS) (Bolton, 1998). The study provided (1) an evaluation of ground-water quality with respect to Federal drinking-water standards, land use, well characteristics, aquifer lithology, and other factors, and (2) baseline data to which future water-quality data can be compared to assess changes in ground-water quality over time. This proposal presents a plan for resampling the wells and springs to determine what changes, if any, have occurred in ground-water quality, and to identify factors associated with observed changes.

Objectives

1. Collect water samples from approximately 50 sites that were sampled as part of the original ground-water study.
2. Evaluate the ground-water quality with respect to data collected during the initial study, particularly with respect to land-use changes.

Approach

Objective #1: Data Collection

1. Write a quality assurance (QA) project plan that describes sampling procedures, sampling and objectives, data reduction and validation, and corrective actions.
2. Purchase necessary equipment and supplies.
3. Obtain permission to resample wells and springs.
4. Collect water samples from approximately 50 wells and springs. To the extent possible, samples will be sampled and processed as in the initial study. It is anticipated that water-quality analysis will be performed by the USGS National Water Quality Laboratory, as was done in the initial study.
5. Document changes in land use that may have occurred since the initial study at or near each site. This will be done using Maryland Office of Planning land-use coverage and by visual inspection of each sampling site.
6. Evaluate water-quality data for accuracy and completeness as it returns from laboratory.

Objective #2: Data Evaluation

1. Summarize all new data in a table similar to table 8 in the original report (Bolton, 1998, p. 88-89). Compare the two data sets to evaluate overall changes in ground-water quality in the study area. This will be done by comparing the two tables and by using appropriate statistical methods such as Mann-Whitney and Kruskal-Wallis rank-sum tests.
2. Compare the old and new data for changes in ground-water quality in different land-use categories. Data will be organized in a figure similar to Figure 21 in the original report (Bolton, 1998, p.55-57). The data will be compared visually and statistically.
3. Evaluate old and new data from sites which have had significant land-use or other changes since the initial study.
4. Analyze data in other ways that address the needs of the cooperating agencies.