| Title | Halifax Harbour extreme water levels in the context of climate change: scenarios for a 100-year planning horizon |
| Download | Downloads |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Forbes, D L ;
Manson, G K; Charles, J; Thompson, K R; Taylor, R B |
| Source | Geological Survey of Canada, Open File 6346, 2009, 26 pages, https://doi.org/10.4095/248196  Open Access |
| Image |  |
| Year | 2009 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| File format | pdf |
| Province | Nova Scotia |
| NTS | 11D/12 |
| Area | Halifax Harbour; Halifax |
| Lat/Long WENS | -63.7500 -63.4500 44.7500 44.5000 |
| Subjects | environmental geology; marine geology; Nature and Environment; water levels; sea level changes; sea level fluctuations; floods; flood potential; mapping techniques; LiDAR; Climate change |
| Illustrations | photographs; location maps; plots; graphs; aerial photographs |
| Program | Climate Change Geoscience |
| Released | 2009 11 19 |
| Abstract | A Halifax Harbour Plan is being developed within the context of the 25-year Regional Municipal Planning Strategy in the Halifax region of Nova Scotia. This strategy recognizes the importance of climate
change and the need for a precautionary approach to minimize negative impacts of rising sea level. Airborne LiDAR data were acquired in 2007 to produce a high-resolution digital elevation model (DEM) as a basis for mapping flood limits. The selection
of flood levels for adaptation planning required an understanding of present and future sea-level rise (SLR), vertical land motion, extreme water levels (combined tide and surge), harbour seiche and wave runup. Relative sea level in Halifax Harbour
has risen at 3.2±0.13 mm/a since 1920 through a combination of regional subsidence (1.6±0.3 mm/a) and local SLR (~1.6 mm/a). Scenarios of future extreme water levels were developed using (1) current local SLR, (2) the upper limit of the 2007 IPCC
projections, and (3) a higher projection based on a growing scientific consensus that the IPCC upper limit may have been overly conservative. These projections of SLR (0.16, 0.59, and 1.3 m over ~100 years) were combined with regional subsidence and
extreme water levels for 2-, 10-, and 50-year events derived from a generalized extreme values distribution of annual extreme water levels in Halifax Harbour. The resulting water levels were applied to the LiDAR DEM to visualise the extent and depth
of flooding for each event. A plausible upper limit with very low probability was developed by superimposing the record storm surge on the highest tide with a sea-level rise of 1.3 m. A buffer ranging from 1 to 2 m was considered to account for
observed values of seiche and wave runup in various parts of the harbour. This study provides the scientific basis for a set of plausible scenarios for a 100-year planning horizon, but the choice of water level for planning purposes is a policy
decision. |
| GEOSCAN ID | 248196 |
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