3D Hydrography (3DHP) Interest Group

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  • 1.  Statewide Flood Hazard and Vulnerability Mapping

    Posted 04-02-2025 10:57

    Hi Folks:

    I am trying to see if anyone has done or procured statewide flood hazard and vulnerability mapping. Connecticut has a had a series of unusual flash flooding events recently and people are realizing that this is a newer significant hazard because of climate change influence rain events, aging and undersized storm water infrastructure, and land use changes (e.g. new development/conversion of forests to IC). Even a damage to a single building, culvert, or road can cost millions of dollars in an expensive and older state like CT. Any ideas or thoughts would be welcome especially on scope and scale. We do have newer DEM, LIdar, and IC data.

    Best,

    Carl Zimmerman, PhD

    CT GIS Office



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    Carl Zimmerman
    GIS Coordinator
    CT GIS Office-OPM DAPA
    Hartford CT
    8608848865
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  • 2.  RE: Statewide Flood Hazard and Vulnerability Mapping

    Posted 04-02-2025 11:45

    Hi Carl,

     

    The California Natural Resources Agency has these flood-related mapping resources, born out of various programs over the years:

     

    Best Available Maps for 100- and 200-year floodplains (required by legislation and completed in 2008). https://gis.bam.water.ca.gov/bam/

     

    Flood Risk Notification https://water.ca.gov/Programs/Flood-Management/Community-Resources/Flood-Risk

     

    Levee Flood Protection Zones  https://gis.lfpz.water.ca.gov/lfpz/

     

    Levee Evaluation Program https://ferix.water.ca.gov/lep/

     

    Dam Breach Inundation Maps https://fmds.water.ca.gov/maps/damim/

     

    Adapting To Rising Tides Bay Area Sea Level Rise and Shoreline Analysis Maps https://data.cnra.ca.gov/dataset/art-bay-area-sea-level-rise-and-shoreline-analysis-maps

     

    In December 2024 the California Geographic Information Association hosted the LiDAR for California Forum. https://cgia.org/cagiscouncil/2024/12/13/lidar-for-california-notes-and-recording/. Starting at about 55:55 is a presentation by Wayne Li of the Department of Water Resources, Risk Assessment and Mapping Section. "LiDAR Data Usage in Floodplain Management".

     

    I hope this is useful.

     

    Jane

     

    Jane Schafer-Kramer, Geographic Data Specialist (she/her)

    Technical Lead for the 3D Hydrography Data Program for CA

    Department of Water Resources, Division of Planning; Data Publication, Exchange, and Management Section

    Office phone and voicemail 279-231-0753

    jane.schafer-kramer@water.ca.gov

    https://data.cnra.ca.gov/dataset/national-hydrography-dataset-nhd

     






  • 3.  RE: Statewide Flood Hazard and Vulnerability Mapping

    Posted 04-03-2025 10:26

    Hi Carl,

    Thanks for bringing this up – I'm curious to hear what others have done and what's possible.

    There are two projects in Vermont that I'm aware of worth mentioning:

    • Transportation Flood Resilience Planning Tool. This maps out road/bridge/culvert vulnerability and criticality to come up with a risk score (and related mitigation strategies.) It was developed/funded by out AoT to help them prioritize mitigation efforts and investment. This wasn't a small effort – but others can likely leverage what went into building the model.  I highly recommend checking it out: https://roadfloodresilience.vermont.gov/#/map Background info: https://vtrans.vermont.gov/climate/trpt
    • Topographically-defined Floodplains with storm sizes reflecting 2, 5, 10, 25, 50, 100, 200, and 500 year peak floods. This work was done by the University of Vermont after creating a model ready DEM from our lidar data. It's derived from a low-complexity hydraulic model/ not a substitute for FIRMs, but by representing the variable inundation extents and including events that are more common (eg 2,5,10, year events) it can be helpful in prioritizing actions. This work is less of a lift than the above transportation work if you have the DEM.  Link to the map and more info:https://vcgi.vermont.gov/data-release/lake-champlain-basin-lidar-informed-flood-inundation-layer-now-available

    Happy to connect you or anyone else with the smart folks responsible for the above projects.

    John



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    John Adams
    VCGI Director
    State of Vermont
    (802) 522-0172
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  • 4.  RE: Statewide Flood Hazard and Vulnerability Mapping

    Posted 04-04-2025 11:57

    Hi Carl,

    Our Best Available Flood Hazard Layer is one of the most popular statewide data layers used by our state agencies. It is updated monthly as new hydrology studies are completed, and in many cases (maybe most?) it is far more up to date than FEMA layers. The data is open to the public on our open data platform, IndianaMap.org: FloodHazard BestAvai DNR Water PROD.

    We have other water-hazard related layers as well, but this is probably the most important one for flood risk mitigation in our state.

    This layer is maintained by our Department of Natural Resources Division of Water, and is the product of a pretty involved chain of tasks that has been developed over a long time. We are pretty fortunate to have some really smart people who have been working on this for a long time. If you want us to facilitate a conversation with them, let me know.

    -Steve Aldrich, PhD, GISP

    GIS Technical Specialist

    Indiana Geographic Information Office (IGIO) 

    M: 317-964-3932 (call or text) | Email: SAldrich@iot.in.gov  

    IGIO-HUB | IGIO LinkedIn 

     

     






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    Stephen Aldrich
    State of Indiana Geographic Information Office
    Indianapolis IN
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