Background

The goal of the L31N Seepage Management Pilot Project is to reduce levee seepage that moves from Everglades National Park to the east. As participants in this pilot project, the South Florida Water Management District (SFWMD), the US Army Corps of Engineers (USACE), and the United States Geological Survey (USGS) are working together to provide a hydrogeologic characterization of the Surficial aquifer underlying the L31N Levee in Miami-Dade County, Florida. Because there is little detailed hydrogeologic data of the Surficial aquifer (to depth) in this area, the L-31N Seepage Management Project Delivery Team (PDT) will install two clusters of monitor wells and four additional coreholes along the levee to provide the necessary detailed hydrogeologic data to the PDT.

Objective

The objectives of this data acquisition project are to provide the on-site geologic expertise while the four coreholes and the deepest well in each cluster are drilled and constructed, and to complete the downhole geophysical logging including video and flow meter logging of these boreholes. The USGS on-site geologist will provide technical guidance to the drill crew, describe the lithology of the core and unconsolidated sediments, and store the cores and sediment samples for the duration of the project. USGS staff will provide and run gamma ray, fluid conductivity and temperature, EM-induction, 3-arm caliper, full wave form sonic tools, a heat-pulse flow meter, an OBI-40 Mark III digital optical tool, and the Laval video tool.

Scope

This project is scheduled to begin in the summer of 2003 (concurrent with the installation of the L31N Seepage Management Pilot Project monitor wells) and will be completed in approximately five months. The purpose is to provide the L31N PDT with knowledgeable hydrogeologic staff with experience in the general area, to guide geologic data acquisition and, to summarize drilling results.

The USGS geologist will be on site while the drill crew is preparing to drill and while drilling, developing, and constructing the four coreholes and the deepest well in each cluster. The site geologist will:

• Monitor the drilling contractor for adherence to the work order specifications including environmental limitations/requirements, borehole development, and well construction,
• Collect, label, and store all geologic samples (cores and liners from SPTs),
• Describe geologic samples in field log book, and
• Summarize hydrogeologic data and other information from the wells and provide to the District staff. This information will not be publicly disseminated or posted on the website until the USGS review process is complete.

USGS staff will run USGS geophysical tools, flow meters, and video tools to log the four coreholes and deepest well in each cluster and will calibrate the sonic velocity log to the seismic reflection profile prepared by Jack Kindinger in 2002.

Work Responsibilities of the Parties

District Responsibilities:

• Contract with licensed drilling contractor to install monitor wells and coreholes,
• Coordinate schedule with drilling contractor and the USGS staff,
• Be available to meet with or talk with on-site geologists to discuss the new data and select well screen intervals, and
• Provide timely review and comments/approval of deliverables.

USGS Responsibilities:

• Provide personnel and equipment, including geophysical tools, flow meters, and video tools required to complete the project,
• Monitor the performance of the drilling contractor to assure adherence to the established scope of work,
• Use USGS geophysical tools, flow meters, and video tools to log four coreholes and the deepest well in each cluster,
• Provide lithologic and geophysical data and other information to District staff to select well-screen interval depths and make other geotechnical decisions,
• Provide deliverables including digital logs, MPG file (mini-movie of borehole video), and computed vuggy porosity logs, as scheduled,
• Calibrate geophysical log data to seismic reflection profiles using newly acquired sonic velocity data, and
• Meet with geotechnical sub-team to discuss findings, if requested.

Schedule