Water Stewardship

Framework for a Hydrogeologic Study

Resource Development Environmental Impact Assessments Suggested Framework for a Hydrogeologic Study

The purpose of a hydrogeologic study for a proposed resource development (i.e. coal, metal mine, etc...) is to define the potential impacts of development on the ground water and interrelated surface water resources and to outline mitigative and monitoring measures to ensure that the quantitative and qualitative integrity of the ground water resource is maintained for future use.

The following guidelines have been prepared to assist development proponents in British Columbia in addressing site specific ground water concerns in their Stage I environmental impact assessment reports. It is recommended that the hydrogeologic study be conducted by a hydrogeologist/ground water specialist. The Ministry of Environment and Environment Canada can be contacted prior to commencement of a study for further advice or direction.

I. Inventory

Inventory and analyze available information on the ground water resource in the area, including: published reports; geologic maps; publications; well record data; exploration test holes; test pits; geophysical data; aerial photographs.

II. Field Investigation

Conduct a field investigation and analyze hydrogeologic data, including:

  • inventory of well users and ground water use;
  • locations and measurements of spring discharges;
  • measurements of water levels and water quality (see attached list of parameters) from test pits, piezometers, exploration holes, adits, test/production wells, springs;
  • pumping test data; permeability test data;
  • geophysical surveys

III. Report

  1. Prepare a hydrogeologic report outlining results of office and site investigation and analysis of data including:

    • general description of physio/geographic setting, topography, drainage, climate, soils, geomorphological conditions;
    • general description of geologic setting, bedrock types (stratigraphy and structural features) and surficial geologic conditions;
    • description of aquifers;
    • hydraulic conductivities; transmissivities;
    • ground water flow systems (local and regional) and flow patterns;
    • rates of ground water movement;
    • flow quantities, including pit inflows and from adits;
    • surface water-ground water interrelationship (i.e. quantity and quality of ground water flowing into/out-of surface waters prior to development);
    • the quantity and quality of ground water to be encountered during development; how and where is ground water to be disposed and/or used;
    • hydrochemical characteristics including anomalies and variations of the ground water quality in the area.

  2. Prepare hydrogeologic maps and cross-sections outlining the extent of unconfined/confined unconsolidated aquifers and permeable bedrock formations; locations of water wells, exploration holes, piezometers, springs, test pits; (potentiometric) water level contours; directions of ground water flows.

  3. Identify potential impacts of development on the ground water resource quantity and quality and interrelated surface water resource, and assess the significance of these impacts in terms of human and fisheries habitat needs. Include potential effects from open pit and/or underground mining development, dewatering, tailings storage facilities, waste rock dumps, ore stockpiles, settling ponds.

  4. Identify measures to be taken to mitigate any significant short and long term potential ground water resource degradation, including use of interceptor wells, grout curtains.

  5. Outline details of purpose, locations and design of monitoring wells in relation to settling ponds, tailings dams, sewage disposal sites, waste dumps, raw material stockpiles, plant processing operations, including number of wells, zone(s) to be monitored, frequency and type of data collection (i.e. water levels, water quality), method of reporting and analyzing data.

Suggested List of Parameters for Ground Water Quality Analyses

I. Field Tests: pH, temperature, conductivity, diss. oxygen

II. Laboratory Tests:
initially for a wide variety of parameters as outlined, followed on a periodic basis by analysis for selected parameters, including anomalous values (i.e. those exceeding Ministry of Environment, Lands and Parks water quality criteria guidelines).

General: pH, Total Diss. Solids, Hardness
Conductivity, Suspended Solids

Anions: Alkalinity(tot.), Nitrates, Fluorides
Chlorides, Nitrites, Cyanides
Sulphates, Phosphates (tot.& ortho)

Cations: Aluminum, Cobalt, Potassium(tot. & Diss.),
Antimony, Copper, Selenium
Arsenic, (tot) Iron, Silicon
Barium , Lead, Silver
Beryllium, Magnesium, Sodium
Bismuth, Manganese, Strontium
Boron, Mercury (tot), Tin
Cadmium, Molybdenum, Titanium
Calcium, Nickel, Vanadium
Chromium, Phosphorus, Zinc

Other: C.O.D. Ammonia-N
T.O.C. Tot. Kjeldahl-N
Tot. Carbon Tot. Phenol