• M.S., Marine Science-Geology, University of South Florida, 1984 • B.A. Geology, Cum Laude, New England College, 1980

• Professional Geologist (P.G.) in the State of Florida
• Certified in Ground Water and Unsaturated Zone Monitoring and Sampling, 1984
• Certified in Health and Safety for Hazardous Waste Site Activities, 1988
• Certified in Project Manager’s health and Safety for Hazardous Waste Site Activities, 1989

• Association of Ground Water Scientists and Engineers

• Contamination assessments
• RCRA investigations and closures
• Feasibility studies
• Remedial action planning
• Computer modeling
• Water resource evaluations
• Water-supply development

Mr. Walker has managed and participated in a wide range of hydrogeologic and environmental investigations and projects including consent order negotiations, contamination assessments, RCRA closures, landfill closures, remedial investigations, feasibility studies, remedial action plans, remedial actions, water resource availability evaluations, and water-supply development projects. Mr. Walker possesses an in-depth knowledge of local, regional, state, and federal regulations and is experienced in the development and implementation of work plans that meet the requirements of CERCLA (Superfund), RCRA, state and other regulations governing contaminant and water resources investigations. Mr. Walker also has provided technical assistance, regulatory advice, and litigation support to clients and attorneys involved in negotiations or litigation regarding environmental issues.

Prior to forming Terra Environmental Services, Inc., as one of four founding Principals, Mr. Walker was an Associate (Officer of the Firm) of Geraghty & Miller, Inc., in Tampa, Florida. In this capacity, Mr. Walker served as project manager for numerous contamination and water resources studies. Mr. Walker also served as project officer for numerous investigations and was responsible for providing technical review and quality assurance/quality control for these and other projects conducted by the firm.

Prior to joining Geraghty & Miller, Mr. Walker held the position of Hydrologist II at the Southwest Florida Water Management District in Brooksville, Florida. While at the District, Mr. Walker participated in the design and sampling of a regional background water quality monitoring network, and developed a database for regional water-quality data.

• Project Manager for soil and ground water investigations conducted at an operating chemical plant in southeast Texas, including evaluation of reported releases to soil and ground water, analysis of potentially-active migration pathways including potential discharge to surface water and sediments, and soil and ground water investigations associated with multiple chemical waste landfill closures.

• Project Manager and Officer for closure of two large industrial process water ponds in north-central Florida. The work was conducted under a RCRA closure permit and involved project planning, negotiations with the FDEP and USEPA, oversight of physical closure activities, and preparation of the closure certification report.

• Co-Project Manager and Officer for negotiating and writing a CERCLA Statement of Work on behalf of a PRP group and implementing response actions at a former metals smelting and fertilizer plant in west-central Illinois. The work has included drilling and testing programs, ground-water sampling and analysis, soil quality investigations, closure of plant facilities and infrastructure, waste characterization and disposal, closure of a 125-acre chemical waste landfill, settling pond closures, pilot testing of various vegetative cover options, storm water management and permitting, treatment wetland design and installation, surface water and sediment investigations, and other tasks.

• Project Officer for a contamination assessment and remedial action for organic chemicals in soil and ground water at a consent order site in west-central Florida. • Project Manager and Officer of a feasibility study conducted for a Superfund site in central Florida. The project involved the evaluation, selection and conceptual design of a preferred remedial action system to clean up ground water impacted with organic chemicals.

• Project Officer for planning, bidding, construction oversight, and reporting for closure of eight above-ground fuel storage tanks in west-central Illinois. The tanks ranged in size from 5,000 to 125,000 gallons.

• Project Manager of source elimination project at a chemical plant in west-central Florida involving the characterization and removal of impacted soils, sludges, and facilities. The project also included the selection and permitting of soil and sludge treatment technologies, reconstruction of remediated areas to minimize future environmental concerns, and development of a contamination assessment plan to address ground-water quality impacts.

• Project Manager and Officer of a contamination assessment at a municipal landfill in west-central Florida, including participation in consent order negotiations, and the design and implementation of a monitor well installation, sampling, and analysis program.

• Project Manager for a perimeter air monitoring program at a CERCLA site in west-central Illinois.

• Project Officer of a Superfund remedial investigation/feasibility study at a former phosphate fertilizer production facility in northwest Florida.

• Project Manager of a supplemental feasibility study at a consent order site in central Florida involving the evaluation of remedial action alternatives for the recovery, treatment, and disposal of ground-water impacted with organic chemicals.

• Project Manager of an investigation involving consent order negotiations, contamination assessment, and remedial action at an mine in central Florida.

• Project Manager and Officer of a contamination assessment in west-central Florida involving consent order negotiations, and the evaluation of metals and organics contamination in soils and ground water.

• Principal author of a water resources feasibility study report for the siting of a major well field in central Hillsborough County, Florida. • Principal author of the hydrogeologic section included in a regional water-supply system operations and management plan for a three-county area in west-central Florida.

• Project Manager of several water-supply development projects for municipalities and private organizations in west-central Florida.

• Project team member for a hydrogeologic investigation conducted in preparation for major litigation regarding riparian rights in central Florida.

• Project Manager and Officer for more than forty hydrocarbon contamination projects involving storage tank removal, soil excavation, soil and ground-water contamination assessments, remedial action planning, and remedial action.

• Project Officer for numerous Phase I, II, and III environmental site audits conducted as conditions of real estate transactions.

• Walker, S.T., 1984, Sedimentary Structures of the West Florida Slope and Eastern Mississippi Cone, Masters Thesis, University of South Florida, Tampa, Florida.

• Moore, D.L., D.W. Martin, S.T. Walker, and J.T. Rauch, 1986, Design and Establishment of a Background Ground-Water Quality Monitor Network in the Southwest Florida Water Management District, Southwest Florida Water management District, Brooksville, Florida.

• Moore, D.L., S.T. Walker, D.W. Martin, and J.T. Rauch, 1986, Ambient Monitor Well Supplemental Report: Potential Monitor Well Locations, Point and Non-Point Source Locations and Hydrogeologic and General Water Use Maps; Ambient Project, Southwest Florida Water Management District, Southwest Florida Water Management District, Brooksville, Florida.

• Moore, D.L., D.W. Martin, S.T. Walker, J.T. Rauch, and G.W. Jones, 1986, Initial Sampling Results of an Ambient Background Monitor Network in the Southwest Florida Water Management District, Southwest Florida Water Management District, Brooksville, Florida.

• Walker, S.T., 1986, A Graphic and Non-Graphic Data Base of Potential Point and Non-Point Sources of Groundwater Pollution in Southwest Florida, in Proceedings-Monitor Wells and Computer Applications to Water Resources, Southeastern Ground Water Symposium, Florida Water Well Association Technical Division, October 30-31, Orlando, Florida.

• Walker, S.T., 1995, Sound Remedial Engineering Design Requires a Marriage of Technical Disciplines, in Proceedings - Florida Environ-mental Expo, September 1995.