| Overview
of Hydrogeological Services
Davis & Floyd, Inc. geologists and hydrogeologists are experienced
in the technical aspects of hydrogeologic investigations and the Federal,
State, and local regulations that relate to these investigations. Our hydrogeologists have investigated the hydrogeologic
characteristics of numerous sites within the varied geologic terrains
of the Southeastern U.S., from unconsolidated, stratified Coastal Plain
sediments to complex, highly fractured bedrock.
Hydrogeological
services provided include evaluation and
development of groundwater supply sources, investigation of soil and
groundwater contamination problems, and remedial design, implementation,
and monitoring.
Our hydrogeologists are experienced
in all aspects of investigation and development of groundwater supply
sources, including analysis of local and regional aquifer characteristics;
well design, construction oversight, and testing; interpretation of
downhole geophysical logs; testing and analysis of aquifer hydraulic
characteristics; groundwater sampling and water quality analysis; and
preparation of groundwater use permit applications. Our hydrogeologists
and engineers have designed wells and water distribution systems for
municipalities and State and Federal governments, industries, and recreational/residential
developers.
Soil
and Groundwater Contamination Assessments
Our hydrogeologists have considerable experience
investigating soil and groundwater contamination due to spills,
leaks, or other sources. We have designed and implemented numerous groundwater
assessment and monitoring programs at landfills, underground storage
tank sites, lagoons, land application sites, uncontrolled hazardous
waste sites, etc.
Remediation Design, Implementation, and
Monitoring
Assessing the extent and
severity of soil and groundwater contamination at numerous sites as
the basis for remedial engineering design, our hydrogeologists have developed and
implemented monitoring programs to evaluate the effectiveness of remedial
efforts.
We have overseen the removal of hazardous wastes and hazardous
materials from controlled (permitted) facilities and uncontrolled sites.
We have prepared sampling and analysis plans, provided field sampling
and laboratory analytical services for characterization of hazardous
materials, and fulfilled regulatory reporting requirements for waste
disposal.
We have designed conventional pump-and-treat groundwater
remediation systems as well as in-situ systems for treatment of contaminated
groundwater and soils. Groundwater extraction systems have been designed
for low-yield, water-table aquifers to high-yield, regional aquifer systems
providing drinking water sources. Our multi-disciplined staff of engineers
designs treatment systems ranging from physical/chemical and biological
systems to complex, ultraviolet radiation/peroxide treatment systems.
Experience
in Hydrogeological Characterization Methods
Experienced in the traditional methods of hydrogeological site characterization,
our geologists and hydrogeologists routinely investigate new and innovative technologies for hydrogeologic
site characterization.
Exploratory
Drilling and Well Construction Oversight
Our geologists have extensive experience in drilling
and downhole sampling methods including conventional rotary techniques,
(air, mud, reverse circulation), conventional and wire-line coring,
air percussion techniques, power auger drilling, split-spoon sampling,
and Shelby-tube™ sampling .
Our hydrogeologists have designed and provided construction
oversight of single- and multiple-cased monitoring wells, immiscible-liquid
recovery wells and groundwater extraction wells, and water supply wells.
We maintain working relationships with drilling
contractors throughout the Southeastern U.S., offering a wide range
of drilling support services at competitive prices.
Aquifer Testing
Our hydrogeological group is experienced
in using and interpreting aquifer tests, including constant-rate
and stepped-rate pumping tests, and borehole permeability (slug) tests
to determine aquifer hydraulic characteristics necessary for evaluation
of groundwater resources and design of groundwater remediation systems.
Geophysical Survey Techniques
Our hydrogeological group has performed
surface geophysical surveys using electromagnetic methods, surface resistivity
methods, and magnetometer for mapping of geologic features, detection
of buried metal, tanks, drums and other objects, delineation of landfill
boundaries, and delineation of groundwater contaminant plumes. Our hydrogeologists
are also experienced in using borehole geophysical logs including resistivity, self-potential, natural gamma, and caliper logs, to determine
subsurface lithologic characteristics.
Direct-Push Technologies
Our geologists have used various methods
of direct-push technology such as cone penetrometer testing; soil, soil-gas,
and groundwater sampling with the Geoprobe™; and groundwater sampling
with the HydroPunch™.
Award Winning Innovative Hydrogeologic Characterization
Technologies
Constantly searching for innovative approaches
to hydrogeologic characterization to arrive at more cost effective and
environmentally sound approaches, we developed a comprehensive
approach to site characterization that was awarded the Consulting Engineers
of South Carolina’s 1997 Engineering Excellence Award.
This technique uses a small diameter depth-discrete sampling port (DDSP),
developed by Westinghouse Savannah River Company, combined with an innovative
drilling method ("Rotasonic") to promote borehole integrity
and produce a high-quality continuous core. This technique also minimizes
investigation-derived waste, employs field screening utilizing a mobile
laboratory to analyze the core and select monitoring zones, and includes
geophysical logging to enhance geologic characterization.
Our approach is
rapid and cost-effective, providing detailed characterization of subsurface
conditions and contaminant distribution. The DDSPs are a simple, yet
effective and inexpensive, tool to characterize subsurface contamination,
providing depth-discrete sampling capabilities in stratified, fractured,
or otherwise heterogeneous geologic settings. The specialized drilling
technique minimizes the quantity of contaminated cuttings that needs
to be disposed, and the use of the field screening allows for quick,
on-site decisions.
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