46 10' N , 60 10' W
Information supplied by
Dated Fri Apr 23 22:18:51 1999
Growth of the area has been controlled by coal mining and the steel industry; fishing and forestry provide secondary employment. During World War II, Sydney Harbour was critically important for the formation of North Atlantic shipping convoys. The harbour facilities presently include the main shipping link to the Island of Newfoundland, loading facilities for coal and steel, as well as docking for cruise ships.
The Sydney Coalfield is the oldest mined coalfield in North America, with mining commencing in the early 1700's. Systematic mining began in 1825 with the mid 1940's being the period of greatest production. By the 1960's only half of the original mines remained in operation. During the 1980's, the province ranked fourth in Canadian coal production, the bulk of which was produced from four mines in this coalfield.
The major towns formed along the shore, associated with the surface facilities of the subsea coal mines. Sydney was founded in 1785 along the shores of the largest harbour; later to be the center of an integrated steel plant - coke oven complex commencing in 1900.
Back to Topics
The east coast of Canada is situated where practically all cyclonic storms of North America leave the continent. This, coupled with the moderating effect of the Atlantic Ocean, gives the area a humid continental climate.
The annual precipitation of 1,480 mm has a good seasonal distribution with maximum precipitation occurring during the fall rains. The Atlantic Hurricane season impacts the region primarily during September to November. Occasionally, the area suffers a direct hit, the latest being by Hurricane Hortense in 1996. Approximately 27% originates as snow. Although intensities are high, the reliability of snow cover is low due to the moderating effect of the ocean.
The mean annual air temperature is 5.5 C with maximum monthly values in July and August; minimum values are below freezing peaking in February -6.5 C. The advent of warmer temperatures is delayed in spring due to pack ice, creating some 80 days of fog/year, with maximums in May, June, and July.
A water balance diagram is provided in Figure 2. There is a large average annual water surplus of approximately 290 mm, occurring predominately in the fall.
Due to the prevailing winds the province lies within the airshed of many densely populated, highly industrial areas on the eastern US seaboard and the central part of the continent. Further there have been up to five major, local, anthropogenic emission sources within the coalfield. The pH of the rainfall varies from 4.5-5.5. Concentration and loading of H+ is greater in the winter.
There are two "long term" climatic trends in evidence. The decadal means of total annual precipitation have increased over 250 mm between the mid 1950's and the late 1980's; since then declines are in evidence. Simultaneously decadal means of mean annual air temperature declined over 1 C .
Back to Topics
The coalfield lies within the Northeastern Appalachian Hydrogeologic Region of North America. It is positioned in a coastal plain setting, best characterized as thin glacial till over bedded sedimentary rock.
The sedimentary rock assemblage comprises a 4000 m thick upward trending sequence of conglomerates, carbonates/evaporites, argillaceous sediments, massive sandstones and a thick coal bearing sequence. The assemblage dips gently northeast under the ocean and has been deformed by a number of gentle northeast trending folds.
The principal hydrostratigraphic unit is the Lower Morien Aquifer comprising the 1,000 m thick massive sandstones (Figure 3) . A secondary aquifer is the Upper Morien Aquifer, comprising the coal bearing sequence.
Flow in the Lower Morien aquifer is fracture controlled with hydraulic conductivities in the 10-3 to 10-6 cm/sec range within the top 100 m. The higher values are found within a 1-5 m thick highly weathered/ fractured zone just below the subcrop surface. Bulk transmissivities derived from open hole water wells with saturated thickness up to 150 m range from 1 to 7 x 10-4 m2/s, with storage coefficients of 5 to 10-4 to 1 x 10-5.The aquifer exhibits a total dissolved solids of 50 - 250 mg/L. It is soft to moderately hard, corrosive, predominately calcium-bicarbonate type water. The pH ranges between 7-8. Iron and manganese create the dominate natural water quality problems.
Given the large water surplus, the bedrock aquifers are for the most part fully saturated throughout the year. Seasonal fluctuation are in the order of 0.5 to 3 m within 100 m open boreholes. Peaks are associated with spring and fall recharge. Minimum values occur primarily during August and September.
Recharge to the bedrock is restricted by the lower permeability of the overlying glacial till and interflow in the podzol soil horizons, which directs shallow subsurface flow to the nearest stream. Estimates of annual recharge for the east coast region from stream baseflow analysis indicate rates from 15-30 cm/yr.
Back to Topics
Back to Topics
A wide variety of groundwater related issues present themselves within the CBRM:
1. Coal-Fuel Cycle: Groundwater problems are associated with the mining, preparation, transportation and end use of relatively high sulfur (2-5%) coal. Acidic drainage from disposal of coarse stone waste and fine tailings as well as, springs issuing from flooded mine workings create the majority of concerns.
2. Steel Plant/Coke Oven Complex: This industrial complex positioned within the City of Sydney (Figure 4) has been operating since 1900; coking operations ceased in 1988. A local estuary named the Tar Ponds received liquid wastes from this complex. It is presently regarded as the largest known chemical waste site in Canada, comprising 700,000 m3 of coal tar contaminated sediment. The Lower Morien Aquifer under the coke oven site is contaminated with a variety of dissolved and NAPL phase organic compounds.
3. Incinerated Municipal/Biomedical Waste: The CBRM operates the only incineration facility for these two waste streams in the province. The determination of the chemical composition of the ash and its leachate is ongoing to aid design of the proper disposal methodology for the ash.
4. On-Site Septic-Well systems: A number of subdivisions are on individual well and septic systems. The appropriate design and the sizing of the lots is becoming critical to ensure individual water supplies are not contaminated.
5. Utilization of groundwater resources for water supply: The commencement of urbanization along the sea coast greater than 100 years ago over the less productive Upper Morien Aquifer, resulted in the development of surface water resources in the interior. Given water quality concerns and stricter guidelines placed on trihalomethane concentrations the push is now to develop the underlying groundwater resources. The City of Sydney has recently developed a groundwater well field to supplant the former surface water system.
6. Coal Fired Thermal Generating Stations: Power generating stations were constructed in proximity to the mine sites. Two stations are presently in operation, supplying a total of 765 MWe to the provincial grid (Figure 3). Groundwater issues center around the proper design and monitoring of the ash disposal sites. The utilization of groundwaters at the Circulating Fluidized Bed plant has required extensive testing and monitoring to ensure the drawdown does not impact domestic wells.
7. Well Head Protection Stratagies: Legislation enacted in the early 1900's provided the provincial government with ownership of all fresh water. Allocation is through a water rights permitting program, well head protection is up to the owner. The City of Sydney is presently implementing a well head protection strategy for its well field. Design of protection guidelines for smaller central groundwater supplies within subdivisions is proving more difficult.
8. Fish Habitat: A number of streams are recognized as important habitat and spawning areas for trout and Atlantic Salmon. The importance of the sport fishery to the economy and the recent decline in Atlantic Salmon is pushing the importance of groundwater- stream interaction to the forefront.
9. Marine Oil Spills: All ship traffic moving into the heart of the North American Continent, passes through the Cabot Strait (Figure 1). The proximity and current movement within the Strait places the shoreline of the CBRM at high risk from marine oil spills. This has highlighted the need to develop large scale oily waste disposal sites, which to date utilize a natural attenuation design philosophy. In 1979 the tanker Kurdistan broke apart in the Strait, releasing 17.3 million litres of bunker C. This required four disposal sites within the CBRM.
10. Mine Water: Seepages and localized flooding events of hypersaline groundwaters (TDS up to 170,000 mg/L) have occurred in workings positioned 1-3 km off shore at depths of 200-600 m below seal level. Studies are on-going to ensure the source is not sea water (thereby minimizing risks to miners) and to understand the source of the elevated TDS, iron, manganese, and ammonia (up to 50 mg/L) in an effort to develop successful treatment strategies for mine water discharge.
11. Salt Water: The recent movement of people out of urban areas and importance of tourism have resulted in the development of shore front properties and difficulties in obtaining suitable individual well supplies not effected by saline formation waters or sea water intrusion.
12. Geotechnical: Groundwater is critical in understanding the collapse of abandoned underground mines through flooding and inadvertent dewatering, as well as stabilizing road side embankments and wave cliff erosion which, along the Atlantic ocean shoreline, ranges from 0.1 to 2 m per year.
13. Large Coal Stockpiles: Large ( 50,000 Tonnes), above grade coal stockpiles are exposed to ambient weather conditions at the power plants and coal preparation plant. Due to the high methane content of Sydney coals, any such product designated for overseas transport by ships must be left exposed for a minimum of 30 days to allow for degassing. Given the high precipitation such exposure increases the moisture content of the coal, which reduces the price, and compounds handling problems. Research into groundwater flow through these piles developed more effective handling operations.
14. LUST: Leaking underground storage tanks have continued to create problems. Legislation enacted in the early 1990's requires the replacement of tanks greater than 15 years old. More recently the increasing demand for environmental audits prior to real estate transactions has highlighted problems with old tanks, residential above ground tanks and spills.
Back to Topics
The concerns centre around the risk posed to homes along the perimeter of the facility, the removal of such a large block of land for building and tax base, as well as the impact of continual transport of contaminants into the harbour. This has resulted in the closure of the lobster fishing industry within the harbour.
Since the late 1980's, monies spent on just the Tar Ponds alone has exceeded $50,000,000, with no cleanup scheduled to date. The complexity of hydrogeological investigations and design of remedial alternatives at the Coke Ovens site is enhanced by the long operational period and size of the site, the wide variety of chemicals handled and the transport of a wide range of organic chemicals in both dissolved and NAPL phases within a fractured bedrock aquifer.
Back to Topics
The initial phase of the Tar Ponds clean up was carried out by provincial and federal governments. Since 1996 it has has been headed up by a coalition of community and government known as the Joint Action Group (JAG). A web page is presently being developed, but is not operational at the present time.
To date hydrogeological studies have focused on delineating the extent and chemical characterisics of groundwater contamination under both the Coke Oven site and the upgradient disposal area, as well as tracking off-site transport into a built up area abutting the northern perimeter of the site.
Solutions to the other issues are site specific and can be obtained by contacting the author.
A second unique community based solution to overall environmental problems in the area is headed up by the Atlantic Coastal Action Program (ACAP) - Cape Breton (web page at ccen.uccb.ns.ca). Their efforts have concentrated on public education, action items (i.e. clean the stream) and development of a comprehensive environmental management plan. The action items when fully achieved would result in the achievement of three components of sustainable development in the local area - A Clean Environment, Sustainable Economy and a Healthy Community.
Back to Topics
- Baechler, F. (1986 ) Water Resources Evaluation of the Sydney Coalfield, Nova Scotia, NS Department of the Environment, 111 pages
- Baechler, F. and MacFarlane, D. (1992), Sydney Tar Ponds Clean-Up: Hydrogeolgoic Assessment
- Coke Oven Complex, in Subsurface Contamination by Immiscible Fluids, ed: Weyer, Balkerma, Rotterdam, pgs 543 - 550.
- Nolan Davis and Assoc. Ltd., 1984, Coal and the Fresh Water Resources of the Bridgeport Basin Watershed, Cape Breton, Nova Scotia, prepared for Environment Canada, 188 pages.
- Randall, A., Francis R., Frimpter, M., and Emery, J., (1988 ) Region 19, Northeastern Appalachians, in The Geology of North America Volume 0-2 Hydrogeology ed by Back, W. Rosenshein J., and Seaber, P. Geological Society of America, Inc., Boulder, Colorado
- Porter Dillon Ltd. 1995, City of Sydney Groundwater Development Phase 3, report to City of Sydney, 45 pgs.
Back to Topics
Fred Baechler, Chief Hydrogeologist, ADI Limited
PO Box 1688, Sydney, Nova Scotia, Canada B1P 6R7
Telephone: 902-562-2394, Fax: 902-564-5660
Mr. Frank Potter, P.Eng.
Cape Breton Regional Municipality
320 Esplanade, Sydney, Nova Scotia, Canada B1P 7B9
Telephone: 902-563-5034, Fax: 902-564-0481
Back to Topics