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Linking climate change and geohazards
Geohazards?
1. What’s the short-list of geohazards potentially relevant to my MCCAP?
2. How are they relevant, and are they priorities?
THANK YOU!• Garth DeMont, Geoscientist with NS Department of Natural Resources• Gavin Kennedy, Hydrogeologist with NS Department of Natural Resources• John Drage, Hydrogeologist with NS Department of Natural Resources
Assessing Geological Hazards 4 of 30
. . . to develop a methodology to incorporate geology into the land use planning process
• coastal flooding & riverine flooding• coastal erosion• land sinking – sinkholes• contamination of water from heavy
metals in soil or acid rock drainage• landslides / slope failure
Geo-events that pose threats
Picture from NS DNR Geological Services Division
Assessing Geological Hazards 4 of 30
. . . to develop a methodology to incorporate geology into the land use planning process
Picture from NS DNR Geological Services Division
Geohazard—Coastal erosion
Picture from NS DNR Geological Services Division
The need to establish setbacks should be informed by geology – both bedrock and surficial
Coastal erosion risk will increase with sea level rise.
Assessing Geological Hazards 4 of 30
. . . to develop a methodology to incorporate geology into the land use planning process
Picture from NS DNR Geological Services Division
Geohazard—Karst
Picture from NS DNR Geological Services Division
Occurs inlimestone & gypsum
• sinkholes• water contamination
Under the Nova Scotia Treatment Standard for Municipal Surface Source Water Treatment Facilities, once designated, karst areas are subject to water treatment standards.
Assessing Geological Hazards 4 of 30
Picture from NS DNR Geological Services Division
Geohazard—Heavy Metals
Toenails, Tap Water and You: The Arsenic ConnectionNS DNR Report of Activities: 2009
Assessing Geological Hazards 4 of 30Geohazard—Heavy Metals
Toenails, Tap Water and You: The Arsenic ConnectionNS DNR Report of Activities: 2009
In unstable climatic conditions where rocks and soilsare saturated one week and dry the next there is ahigher risk of transport into groundwater systems.
Will that be our climate?
Assessing Geological Hazards 4 of 30Geohazard—Acid rock drainage
Pyrite and pyrrhotite oxidize when exposed to air, resulting in production of sulphuric acid and iron oxides.
Sulphuric acid is soluble.
Picture from NASA Earth Science Division
Assessing Geological Hazards 4 of 30Geohazard—Acid rock drainage
The amount of water that will fall in a ‘20 year return period’ rainfall (i.e., an event that has a 5% chance of happening any given year) will be:
5% more rain fall by the 2020s9% more rain will fall by 2050s
16% more rain fall by the 2080s.
Picture from NASA Earth Science Division
Assessing Geological Hazards 4 of 30
Picture from NS DNR Geological Services Division
Geohazard—Slope stability
• Slope angle?• What’s beneath our feet? On surface and underlying?• How saturated is it?• How warm is it?
different kind of assessment than coastal erosion Slope Stability Guidelines for Development Applications
Decision Flow Diagram
Assessing Geological Hazards
•Understand how climate change can trigger certain hazards
•Are any of these hazards present in my jurisdiction?
•Where?
•Do they impose an intolerable risk?
•How urgent is the need to respond?
