Background

The goal of the L31N Seepage Management Pilot Project is to reduce levee seepage that moves from Everglades National Park to the east. The South Florida Water Management District (SFWMD), US Army Corps of Engineers (USACE), and 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 hydrogeologic data of the Surficial aquifer (to depth) in this area, the L-31N Seepage Management Project Delivery Team (PDT) will obtain geologic core samples and geophysical logs, including flow meter and video logs from 6 boreholes drilled along the L31N levee. This along with other hydrologic data should provide the necessary detailed hydrogeologic information to the PDT.

Objective

The objective of this data interpretation project is to provide the PDT with detailed hydrogeologic information in order to understand the movement of water in the Surficial aquifer along the L31N levee and delineate the lithology and hydrostratigraphy of the rocks and sediments underlying the levee. The geotechnical subteam needs preferential and low flow zones, porosity values, and geologic framework identified in order to establish baseline conditions, make plan design recommendations, and model the various alternatives. The USGS staff will provide this hydrogeologic information using the geophysical logs, including flow meter, video, and digital borehole image logs, and the geologic core samples obtained by SFWMD contractors from four drilled coreholes and two deep monitor wells along the L31N levee.

Scope

This project will begin after completion of the drilling and logging of four coreholes and two deep monitoring wells in the L31N Levee area. Drilling and logging of these six boreholes is expected to be completed about October 15, 2003. The data interpretation will be completed in several steps. USGS staff will examine the cores and unconsolidated sediment samples and prepare detailed hydrostratigraphic descriptions of four 70-foot cores and two 110-foot cores. USGS staff will also process the geophysical, flow meter, and video logs to construct six log montages, which include digital borehole images, computed vuggy porosity, caliper, temperature, conductivity, gamma ray, full-waveform sonic, and rock fabric facies logs. A hydrostratigraphic cross section will be delivered as a USGS Open-File report to be finalized in FY2004.

Work Responsibilities of the Parties

District Responsibilities:

• Contract with licensed drilling contractor to obtain cores and unconsolidated sediment samples and provide same to USGS.
• Be available to meet with or talk with USGS staff to discuss findings.
• Provide timely review and comments/approval of deliverables.

USGS Responsibilities:

• Provide personnel and equipment, including appropriate software necessary to complete the project.
• Provide USGS hydrostratigraphic data as needed to complete the project.
• Provide deliverables (six log montages, a hydrostratigraphic cross section as an Open-File report in the form of a plate) as scheduled. This information will not be publicly disseminated or posted on the website until the USGS review process is complete.
• Present findings to the PDT.

Schedule

This project will begin when the drilling contractor has completed the two L31N monitor wells and four coreholes. It is expected that this will occur about October 15, 2003. The detailed core descriptions and the log montages will be completed within four months. The draft Open-File report in the form of a plate will be delivered to the District within eight months of completion of the four coreholes and two deep monitoring wells.

Task/Deliverable	Due Date
Preparation of hydrostratigraphic descriptions of four 70-foot cores and two 110-foot cores that will be presented on log montages	4 months from completion of coreholes (estimated 02/15/04)
Process geophysical, flow meter, and video logs and construct six log montages	4 months from completion of coreholes (estimated 02/15/04)
Deliver log montages, and draft cross-section of select geophysical logs and hydrostratigraphy	4 months from completion of coreholes (estimated 02/15/04)
Deliver draft of USGS Open-File Report in the form of a plate	8 months from completion of coreholes (estimated 06/15/04)
Present results to the PDT	After draft report completed