Transcript
Today’s Talk
• Introduction• Why is the OGS doing 3-D mapping?
• Where are we working?
• What are the goals?
• How do we go about 3-D mapping
• What do we produce?
Why is the OGS doing 3-D mapping?
• Contaminated municipal water
• Walkerton Inquiry
• Provincial legislation!!!!!
Legislation
Source Water Protection Plans• Watershed characterization• Water budget• Aquifer recharge• Aquifer vulnerability• Well head protection areas• Threats to drinking water Greenbelt Act
Places to Grow Act
Build a 3D model of Quaternary deposits
that form regional-scale aquifers and
aquitards
• Reconstruct the regional Quaternary history and develop a conceptual geological framework
• Construct a 3D model of key sediment packages
• Characterize the properties of modelled sediment packages
Glaciolacustrine sediments
Till
Peat
Shallow water glaciolacustrine Glaciolacustrine
Outwash
Peat
Shallow water
Beverly Swamp
Southern WetlandsDune
Reactivation
Glaciolacustrine
Sediments
Peat
Till
Dune Reactivation
Glaciolacustrine
Sediments
Peat
4440 BP 8235 BP
Till
Deformed deep water
glaciolacustrine sediments
Shallow water glaciolacustrine
sediments
Shore
Till
Deformed deep water
glaciolacustrine sediments
Deep water glaciolacustrine
sediments
Shore
Ground-based gravity surveys• Show the least sensitivity
to cultural interference.
• Not affected by stratigraphy (velocity contrasts of stratigraphic units) and depth to water table.
• Simple and cheap
Reduce and translate
SandSandyQuicksandMedium sandCoarse sand
Sand
New Term Original Term 1
Original Term 2
Original Term 3
Gravel Gravel Packed Water-bearing
Sand Sand Sand Silt
Sand Sand Soft Clean
Clay Clay Sticky Soft
Diamicton Clay Sand Gravel
Diamicton Hardpan NA NA
Surficial GeologyWe are a long way from Niagara…
• Lots of till (green)
• Lots of sand and gravel (orange and beige)
• LANDFORMS!!!!
What about those tills?• Tiny windows into older glaciations
• Some tills look different, some don’t
• PSA, Chittick, HM, Pebbles, fabrics
• LANDFORMS
Older Sediments
• Weathered bedrock and contact aquifer
• Older tills (aquitards)• Stratified sediments
overlying the tills (aquifers)
NW
SE
5 cm
5 cm
5 cm
5 cm
Late Wisconsin Glaciation
• Early lobate flow• Main glaciation
characterized by regional flow
NW SE
5 cm
5 cm
5 cm
Breakup of Catfish Creek Ice• Ice thins and
begins to break up• Glaciolacustrine
sediments and fine-textured diamicton deposited
• Rare coarse-textured glaciofluvial sediments
NW SE
5 cm
5 cm
5 cm
Orangeville Moraine
• Paleoflow directions to the southwest
• Coarse-textured proximal sediments
• Fine-textured distal sediments dominant
NW SE
Ice from all directions
• Port Bruce advance of Ontario, Huron and Simcoe lobe ice
• Advanced over the flanks of the Orangeville moraine
• Drumlins, streamlined landforms, till fabrics
NW SE
5 cm
5 cm
5 cm
What our clients want to know
• Aquifer or aquitard?
• Location / continuity?
• Thickness / volume?
• Surface elevation?
• Pathways?
• Characteristics?
• Reliability?
Products: guiding principles
• Standardized from one project area to the next
• Terminology and geologic conceptualizations need to be standardized to allow for merging of models
• Products need to be useable by a wide range of clients
• Need to release products that eliminate the need for high-end computers or software to use the data.
Products
Groundwater Resource Studies
Datamine exports of volumes and grids for hydrogeologists
and geoscience specialists
Interactive drillhole data
Maps and Cross-Sections
Prepared cross-sections
Aquifer recharge and vulnerability maps
Structural contour and isopach maps
Groundwater Applications
• Source water protection
• Search for new water supplies
• Groundwater flow models
• Tier 2 and 3 water budgets
• Monitoring wells (PGMN)
• Sanitary landfill planning
• Remediation of Ontario’s brownfields
• Nutrient management plans
Resource Applications
• Protection of sensitive ecosystems
• Environmental Bill of Rights
• Geotechnical studies
• Bridges and overpasses
• Building foundations
• Resource development
• Search for buried aggregate
Scientific Applications
• Stratigraphic studies
• Improved regional framework
• New radiocarbon dates
• Climate Change
• The past is the key to the future
Measured sections, borehole logs and geophysical profiles are excellent primary data
sources
Summary
• Rural and urban Ontarians rely on overburden aquifers for their water supply.
• The OGS is engaged in the effort to find, assess and protect Ontario’s
groundwater resource through regional scale and targeted 3-D surficial
aquifer mapping projects.
• Each 3-D project addresses
• Quaternary history
• Conceptual framework
• 3-D mapping
• Interpretation
• Groundwater resource reports, digital datasets, maps, cross-sections and
Google Earth applications are key products.
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