home » experience » environmental geology and hydrogeology

Environmental Geology and Hydrogeology


Keltic Petrochemicals Inc.

Keltic Petrochemicals Inc. hired earth-water Concepts inc. as part of a scientific team to conduct the surface water hydrology, geology and hydrogeology components of environmental impact assessments for: 1) a proposed petrochemical plant, co-generation electrical power plant, and LNG receiving terminal at the community of Goldboro on the eastern shore of Nova Scotia; and 2) a 58 km long stretch of new 100-series-type highway proposed to extend from east of the plant site, across the province to the Trans-Canada highway at Antigonish on Nova Scotia's north shore.

The proposed petrochemical plant site is located at a former gold district and contains several dozen mine shafts, extensive underground workings, and four former gold mill (mercury amalgam) tailings disposal ponds. The ~300 hectare site is underlain by a thin layer of glacial till and low-permeability metasediments that are significantly folded and faulted. Fault zone fracture flow and old unmapped mine workings, some known to be in direct hydraulic contact with the ocean, have the potential to produce complex groundwater flows at the site. The plant also needs a 20.3 million US gpd water supply (see here) that requires raising a lake level and flooding an area about twice the size of the lake. The proposed highway route traverses an entire geologic cross-section of the province, and crosses 38 streams in 21 secondary watersheds located in 5 primary surface watersheds.

Working closely with the terrestrial biologists on the science team, earth-water Concepts inc. undertook comprehensive investigations that included:

  • in-depth library reviews of old mining reports to locate mine workings, underground maps and former tailings disposal areas at the proposed plant site,
  • field mapping of the plant site geology, extensive soil, stream water and stream sediment sampling to assess past mining legacies and serve as a new baseline,
  • installation, hydraulic testing and groundwater sampling at several piezometer nests located on and off the proposed plan site,
  • a detailed well survey and water quality sampling program that incorporated all wells within the community of Goldboro and beyond,
  • assessment of potential groundwater, surface-water and ecosystem interactions related to land form changes necessary for plant-site construction,
  • assessment of predicted global climate changes and possible tsunami on the long-term viability of the proposed site and sustainability of the petrochemical and LNG project,
  • general surveys of several hundred water supply wells within a 1 km buffer zone along the entire proposed highway alignment,
  • geological map and exploration assessment file review for base metal interests along the entire proposed highway alignment to identify areas with potential acid generating rock,
  • road and helicopter visits to evaluate all proposed road-stream crossings, and preliminary numerical assessments of annual and seasonal stream flows at all crossings.

Trans-Canada Highway Twinning

While employed at Public Works and Government Services Canada, the principal at earth-water Concepts inc. was assigned to carry out the geology and hydrogeology components of an environmental assessment along approximately 60 km of existing road for the twinning of Highway 104 from Oxford to Kemptown, Nova Scotia. This provincial-federal construction project required a significant widening of the existing highway right-of-way, and land surface grading changes that could potentially impact streams and water supply wells due to changes in water levels during construction and the application of additional road salt during winter highway operation. Working closely with associate biologists, a comprehensive investigation was carried out that included:

  • desktop and field mapping of the soil and bedrock geology along the entire section of highway under assessment,
  • review of mineral exploration assessment files for base metal interests along the entire route to identify areas with potential acid generating rock,
  • surveys of all water supply wells located within anticipated zones of influence,
  • evaluation of all stream crossings to identify and assess the potential for new impacts due to surface flow changes,
  • evaluation of possible groundwater sensitive ecosystems and possible impacts to them due to construction and operational changes along the subject stretch of highway.

Imperial Oil Divestitures

Following the purchase of a number of former McColl-Frontenac (Texaco) bulk fuel distribution and service station properties in Atlantic Canada, Imperial Oil Canada was ordered by the Federal Government under terms of the Competition Act to divest of a number of the newly acquired sites. While it had purchased the sites as-is, there were concerns of pursuing liability during the resale of properties, and Imperial Oil embarked upon a broad environmental assessment and clean-up program for all sites.

While employed by others, the principal at earth-water Concepts inc. staff directly managed and carried out the geology, geochemistry, and hydrogeology components of the investigations and remediation design of over two dozen petroleum sites. All sites were worked on simultaneously and on a very tight schedule to meet property resale conditions. The work, where individual projects were valued at over $1 million at some sites, included the development and implementation of unique and innovative site investigative and clean-up techniques that were borrowed from past experience while doing petroleum resources exploration work. All of the assessment and remediation work was completed on time and below budget.

Advise to Insurance Companies

The predecessor company to earth-water Concepts inc. was called upon regularly by a number of insurance company clients to help in subsurface assessments for the clean-up of residential and other heating oil and gasoline spills. Typical projects, with assessment and clean-up costs ranging from several tens to several hundred thousand dollars, usually involved multiple properties on which there had been multiple spills over time. The earth-water Concepts inc. staff members were called upon to evaluate site water and soil samples and analyse laboratory data for proper petroleum product fingerprinting in efforts to differentiate various spill events and spill ownership. This data was used by client firms to seek proper subrogation where other insurance firms were involved.

All contents © 2010 earth-water Concepts inc. All rights reserved.