CICEET progress report for the period of 2/1/00 to 7/31/00

Project Title:

Measurement System for Localizing Groundwater Flows into an Estuarine Environment

Principal Investigator (s):

Charles C. Sarabun
Daniel G. Ondercin
Linda Frizzell-Makowski
The Johns Hopkins University
Applied Physics Laboratory

William S.L. Banks
Jonathan J.A. Dillow
U.S. Geological Survey

I. Work Accomplishments

    1. Tasks for the Period.

      1. Complete and test the sensor suite.
      2. Conduct OPC surveys. Analyze results.
      3. Conduct detailed surveys in regions identified in IAb.

B. Work Plan to Accomplish Tasks.

C. Concerns or Difficulties.

a. Four large-scale surveys conducted. Considerable variability was observed between surveys from real-time data displays. A main system disk crash occurred prior to beginning the data analysis. The system was sent to a commercial company to attempt data recovery. Of four surveys, only two had full data sets. One of these, conducted 8 September 2000 was during southwest winds and the water column was wind stirred and well mixed. Figure 1 shows the lack of detail indicating a significant degree of mixing. The main results derive from the final survey conducted on 22 September 2000.

 

D. Anticipated Success in Meeting Project Objectives in Scheduled Project Period.

a. The delay in analysis resulting from the need to ship the data archive system to a commercial company precluded a return to Otter Point Creek (OPC), MD for localized, fine grid surveys. We anticipate a return to OPC in 2001 to complete small-scale survey(s). To obviate the data loss problem in the future, we will be archiving data on a CD-ROM.

E. Preliminary data

A. The thermal surveys conducted in March, 2000 suggested some potential areas of groundwater inflow. Figure 2 shows regions of high temperature variability in Otter Point Creek. The survey conducted on 22 September 20000 showed some variability in temperature and conductivity but, as with the Bush River results from 1997, the most significant variability was seen in pH, figure 3. Analysis of the groundwater and OPC water samples taken in March showed low pH for the groundwater and high pH for the OPC water. Despite the smoothing inherent in contouring data, four localized areas of lower pH show in the survey data. Three of the potential groundwater input sites are near-shore sites and correspond to locations identified in the thermal surveys. Figure 4 shows the September pH contours overlaid on a map of OPC. The inset shows the temperature field from the March thermal survey and the correspondence between the thermal indicators and the near-shore lower pH regions. The central and western shore sites are locations of groundwater seeps on the shore visually observed during the thermal surveys; although there was no obvious seepage observed during the September survey. The eastern-most sites, labeled 3 and 4) are located in deeper water, figure 5, and are the most interesting. No shore seep was observed during the thermal surveys in the vicinity of these sites. In the thermal survey, a small pocket of warmer water was observed which corresponds to a small pocket of lower pH labeled3 in figure 3. However, there is also a broader region of lower pH, labeled 4, that corresponds to deeper, colder water in the thermal survey. All of these lower pH areas are located near-shore. Figure 3 also shows one off-shore area of low pH, labeled 5, that may represent the type of subsurface seep that is the object of the detection methodology we are developing. We will revisit these areas in 2001 to conduct small-scale surveys.

 

 

II. Tasks and Activities for the Next Report Period.

A. Tasks for the Next Report Period.

    1. Assemble geological information for the Jug Bay region.
    2. Sink temporary groundwater well at Jug Bay, MD to sample groundwater. Simultaneously sample Patuxent River water at the Jug Bay NERR site.
    3. Analyze water samples and define sensor suite.
    4. Assemble sensor suite.
    5. Conduct large-scale surveys of the Jug Bay region. And analyze the resulting data.
    6. Conduct detailed surveys in regions identified in IIAe.
    7. Conduct small-scale surveys in OPC.
    8. Time and funding permitting, survey Blackbird Creek NERR site in Delaware.
    9. Produce final project report.

B. Work Plan to Accomplish Tasks.

    1. Groundwater and river water samples collected late February-early March with subsequent laboratory analysis.
    2. March 2001 - Define sensor suite.
    3. March-May, 2001 — Assemble and test sensor suite.
    4. May-June, 2001 — Conduct large-scale surveys and analyze resulting data sets. Define localization areas from the large-scale results.
    5. June, 2001 — Conduct small-scale, localization surveys.
    6. June-August, 2001 — Data analysis and interpretation. Critical assessment of results and methodology.
    7. August-September, 2001 — Preparation of project final report and a separate report detailing the developed methodology and it’s implementation for distribution to interested parties.

C. Concerns or Difficulties

The major concern for the Jug Bay and, potentially, the Blackbird Creeks sites is that the target areas are main channel areas, thus, we will need to conduct these surveys at or near slack water to ensure that seeping groundwater is not immediately mixed with overlying river water.

III. Expenditures

Report submitted separately by JHU/APL accounting. Project expenditures were within the range anticipated for the first years work.