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Source-of-Supply Investigation
Isaacs Harbour River Watershed
In this project-in-progress, earth-water Concepts inc. was hired to conduct a regional study on Nova Scotia's Eastern Shore for a 76,800 m3/d (20.3 million US gpd) water supply for a petrochemical plant, LNG receiving terminal, and 200 MW power plant. The site is in a rural area where shallow wells dug into clayey glacial tills are the local source of water for residences and small industry.
The
study involves four watersheds that are 900, 7745, 8340 and
32460
hectares in size and each discharge via well developed
drainage
systems into the Atlantic Ocean. The
larger watershed drains to the east and is underlain by relatively well
drained soils and permeable sandstone.
The other watersheds are situated topographically below the larger one,
drain to the south, and have a thin glacial till cover over
impermeable meta sediments that also form the basement bedrock
complex beneath the sandstone units at the larger watershed. Major
faults with several kilometers of lateral displacement along them in
the meta sediments, are believed to also extend
under the
sandstone horizons beneath larger watershed.
The 7745 hectare Isaacs Harbour River watershed and the 900 hectare Goldbrook sub-watershed were identified as primary and possible short-term backup water source candidates, respectively, based on proximity to the plant site, and availability of lakes that could serve as reservoirs. earth-water Concepts inc. performed a comprehensive investigation that:
- included installing rain guages on the coast and inland where data was missing, large-scale GIS precipitation modeling based on field and government data, and installation of four stream guages to record continuous stream flows for 20 months,
- characterized water balances and capacity for the subject watersheds, defined reservoir requirements, and preliminary criteria for water taking, dam, and fish way design,
- identified river discharge surplus, flash vs. base flow, and contributions to river discharge via groundwater sub-flow from the northern watershed via the regional faults,
- forms the basis for doing range of variability determinations for ecological stream flow maintenance, and for withdrawal permitting.
Chester Water Supply Options
The village of Chester, Nova Scotia, is a coastal community
of about 2,000
people that has a central sewage collection and
treatment system, but where individual
water wells service its residents and businesses. Many of the water
supplies consist of shallow dug wells with a history of going
dry during the summer. There is concern, with the
possibility of groundwater draining through 
the
backfill in the sewer-line trenches, and with decreased groundwater
recharge possible due to climate change, that the
numbers and duration of wells going dry could
increase.
Earlier groundwater work by earth-water Concepts inc. suggests that wells drilled into the local meta sedimentary bedrock could meet water demand, but high iron concentrations are likely to require treatment. A lake situated in a relatively pristine watershed and within a reasonable distance of the village, could also serve as a water source. earth-water Concepts inc. was hired to perform a study that:
- monitors groundwater levels in drilled and dug wells within the village,
- defines the effects that sewer collection-system trenches may have on groundwater through 3-D mapping and groundwater level modeling,
- characterizes the nearby watershed capacity and water quality through a comprehensive water sampling program and installation of lake level and stream guaging stations,
- systematically evaluates the groundwater and surface water supply options.
Town of Yarmouth Reservoir
The
Town of Yarmouth wanted to evaluate their surface water supply
reservoir before doing reconstruction work on an existing
earth and concrete
dam. earth-water Concepts inc. was hired by the
municipality's civil engineering firm to define total watershed
capability, the ability of the storage reservoir to meet
existing demand, storage requirements to meet future demand,
and an overall water balance to help confirm estimates of
withdrawals from the lake. The assessment identified a
significant difference between water
into and out of the lake, which was accounted for
eventually through the discovery of large leaks in the town's
water distribution system.
Sherwood Golf Course Expansion
The Sherwood Golf Course is a private course located on the south shore of Nova Scotia. The site is situated within a granite batholith terrain where fracture flow is the only form of aquifer permeability, and where soils are generally thin, offering very little groundwater storage.
The owner is considering expanding the golf course, but first wants to assess the potential for irrigating the additional lands, and the ability to design the expansion in a way that will not interfere with source development but instead, will enhance it. earth-water Concepts inc. was hired to conduct a study of the local watershed that evaluates:
- the total amount of water falling onto, and available within, the watershed
- groundwater recharge and discharge areas, and the potential total recharge,
- well yield potentials, and
- surface water and groundwater interactions.
The study required a detailed lineament analysis to
help locate possible bedrock faults, define rock
fracture density, and identify the potential for groundwater
flow, the most likely groundwater flow paths relative to the
golf course, and locations with the potential for
greatest well yields.
Private Hydro Project
earth-water
Concepts inc. was hired to conduct a regional surface water study in
northern Nova Scotia. The purpose of the
study was to investigate water resources in the area and to
find and help develop a water source to support a proposed
hydro-electric project to produce electrical power for market and for research on new water turbine technologies.
There are no guaged watersheds nearby, so for this study in progress, work was begun by installing stream guages at select locations within key watershed systems. This study will evaluate: total annual availability of water in the guaged watersheds; seasonal and longer-term variability of supply, and seasonal variability of flows possibly available for power generation; reservoir storage needs to reduce seasonal variability in water volumes and flows; terrain and slope analysis to identify the best locations for water taking in order to meet power generating requirements; and water taking and reservoir management criteria and schedules to maintain ecological systems both at the reservoir, water taking location, and downstream of the power generating facility.