#floodhazardmapping — Public Fediverse posts

Beyond The 100-Year Flood - Probabilistic Flood Hazard Assessment For King And Pierce Counties Under Future Climate Scenarios
--
https://doi.org/10.5194/nhess-26-3231-2026 <-- shared #openacess paper
--
[part of my old stomping ground as an engineering geologist]
H/T @Kees Nederhoff
“Flood maps are usually built from a single design storm. For King and Pierce Counties in the Pacific Northwest (USA), [the authors] tried the opposite - simulate 82 years of actual coastal and river conditions (plus 18 synthetic years) with SFINCS and let the statistics fall out cell by cell. That took about 5,400 yearly simulations and 194,000 CPU hours on USGS's Hovenweep HPC. Worth it!
The design-event shortcut turns out to hide a real hazard. A deterministic 10-year event underestimated flood depths by up to half a meter compared to the continuous runs.
The bigger surprise [to the authors] was how one-sided the climate signal is. One metre of sea level rise takes King County's expected annual flooded area from 161 --> 787 hectares, almost a factor of five. Changes in storminess over the same horizon barely register. And somewhere between 100 and 150 cm of SLR, land that never floods today starts flooding fast. If you plan adaptation in Puget Sound, that threshold matters more than any single return-period map.
[They] also propose Expected Annual Flooded Area (EAFA) as a probability-weighted alternative to the binary "inside or outside the 100-year zone" label…”
#USGS #supercomputing #Hovenweep #HPC #coast #coastal #PNW #Seattle #PacificNorthwest #risk #hazard #riskmanagement #model #modeling #CFRM #deterministic #probabilistic #climatechange #extremeweather #fedscience #WA #KingCounty #PierceCounty #WashingtonState #USA #flood #flooding #compoundflooding #floodmaps #SFINCS #storm #weather #climate #climatechange #rainfall #precipitation #sealevel #sealevelrise #SLR #100yearflood #floodhazardmapping #returnperiods #pluvial #fluvial #spatialanalysis #spatiotemporal #remotesensing #streamgage #history #historicflooding #projections #predictions
#USGS

Advancing Detailed Flood Hazard Identification in Alberta, Canada - Insights from Two Recent Flood Studies
--
https://doi.org/10.3390/w18131592 <-- shared paper
--
“The increasing frequency of floods and the severity of their consequences for public safety, infrastructure, and the economy demand improved methods for flood hazard identification. Flood studies that include flood hazard mapping are critical tools for informing emergency response and flood recovery, as well as for land use and mitigation planning. The methodology for such flood studies has evolved, and access to more powerful computational resources and high-resolution base data has contributed to the increased use of two-dimensional hydraulic modelling, where one-dimensional modelling previously was the default. However, local-scale flood studies face real-world constraints, including sparse data, challenging hydrologic conditions, and budget limitations, which can hinder the application of advanced techniques. This study addresses these challenges through innovative, practice-driven solutions in two case studies in Alberta, Canada: a small, partly channelised prairie stream network (Wolf Creek, Lacombe) and a laterally dynamic river on a distributary delta (Swan River, Kinuso). Three core components of flood hazard studies are described: field survey data collection, regional hydrology assessment, and hydraulic modelling. Key findings include demonstrating that LiDAR-derived terrain models alone cannot capture channel conveyance, the importance of low-flow calibration in the absence of high-water marks, the selection of a modelling methodology based on bathymetric and topographic features within a study area, and the development of inflow hydrographs for unsteady-state simulation in flat floodplains…”
#FloodMapping #FloodRisk #Hydrology #HydraulicModeling #HECRAS #WaterResources #Alberta #Resilience #RiverSurvey #spatialanlaysis #spatiotemporal #floodhazardmapping #HECRAS #model #modeling #remotesensing #LiDAR #bathymetry #floodfrequencyanalysis #unsteadysimulation #FHIMP #FHIP #WoldCreek #Lacombe #SwanRiver #Kinuso #Alberta #Canada #localscale #provincialfloodstudy # prairie #stream #river #flood #flooding #water #hydrology #risk #hazard #watershed #publicsafety #cost #damage #economics #infrastructure #use #practicedriven #floodhazard #survey #hydraulic #terrainmodels #hydrogeomorphology #topography #elevation #floodplain
@Alberta Environment and Protected Areas | @Government of Alberta | @Barr Engineering

[Canadian] National Elevation Data Strategy Newsletter [NRCAN]
--
https://gogeomatics.ca/national-elevation-data-strategy-a-significant-coverage-increase/ <-- shared technical newsletter
--
#GIS #spatial #mapping #remotesensing #LiDAR #elevation #opendata #airborneLiDAR #AutomaticallyExtractedBuildings #buildingfootprints #Canada #CanElevation #CGVD2013 #CopernicusDEM #dataacquisition #digitalelevationmodel #DEM #Digitalsurfacemodel #DigitalTerrainModel #DSM #DTM #elevationproducts #FloodHazardMapping #geographicdata #highresolutiondata #HRDEM #HRDEMmosaic #PointCloud #mediumresolutionelevationmodel #MRDEM #NAD83 #NationalElevationDataStrategy #NRCAN #topographicaldata #vectorformat #flood #flooding #extremeweather #climatechange #naturalhazard #risk #hazard #datacoverage
@NRCAN

Mapping Current And Future Flood Exposure Using A 5 Metre Flood Model And Climate Change Projections [Vancouver, B.C., Canada]
--
https://doi.org/10.5194/nhess-24-699-2024 <-- shared article
--
#GIS #spatial #mapping #climatechange #hazards #naturalhazards #flood #flooding #innundation #disaster #risk #management #planning #floodhazardmapping #Vancouver #BritishColumbia #Canada #highresolution #scenarios #builtenvironment #coast #coastal #coastalengineering #fluvial #pluvial #stormsurge #engineering #model #modeling #spatialanalysis #spatiotemporal #policy #urbanplanning #regulatory #regulations #highresolution