Road network analyses elucidate hidden costs of road flooding under accelerating sea level rise

Introduction: As sea level rises and coastal communities simultaneously grow, road flooding has the potential to significantly disrupt travel along road networks and make houses, businesses, and critical facilities difficult to reach. The impacts of tidal and storm surge flooding on roadways present challenging social and economic considerations for all coastal jurisdictions. Maintenance, public and private accessibility, evacuation routes, emergency services are just a few of the common themes local governments are beginning to address for low-lying roadways currently known to flood. Continuation of these services allows a community to thrive, to maintain or increase its tax base, and to ensure the safety and well-being of its citizenry. Methods: A traditional approach to analyzing road flood overlays flooding areas on roadways and focuses only on impacts within the actual zone of inundation. However, road flooding can also cut-off access to non-flooded roads and properties, closing the transportation corridor into or out of their downstream dwelling/service areas and other areas that may be impacted. In this study, we examined changing road inaccessibility under accelerating sea level rise for urban and rural localities. Results: Inaccessibility of roads and properties increased nearly twice as much as would be suggested by the length of flooded roads. Overall vulnerability of a locality was primarily dependent on its elevation; however, the redundancy of the road network appears to affect the rate at which properties became inaccessible. Areas with complex and redundant road networks-maintained access to coastal properties longer, suggesting increased resilience in the near term. Discussion: Road inaccessibility will impact property values and emergency response times but understanding the connection between flooding areas and inaccessible properties allows prioritization of road upgrades, improving overall coastal resilience

York County Shoreline Situation Report 1999

This report represents the first attempt to update the earlier Shoreline Situation Reports. It \u27s purpose is to present recent shoreline conditions, and evaluate, where possible, the change in shore condition since previous reports. New information is presented for areas not previously surveyed. Additional attributes have also been added in phase two. Some information, however, was not computed as part of this second reporting phase, and reference to earlier conditions may be presented. For example, revised shoreline erosion and accretion rates were not computed, but knowledge of previous rates may be of interest in some areas. These are included in this report

James City County Shoreline Situation Report 1999

This report represents the first attempt to update the earlier Shoreline Situation Reports. It\u27s purpose is to present recent shoreline conditions. and evaluate, where possible, the change in shore condition since previous reports. New information is presented for areas not previously surveyed. Additional attributes have also been added in phase two. Some information, however, was not computed as part of this second reporting phase, and reference to earlier conditions may be presented. For example, revised shoreline erosion and accretion rates were not computed, but knowledge of previous rates may be of interest in some areas. These are included in this report

Summary Tables: New Kent County, Virginia Shoreline Inventory Report

The Shoreline Inventory Summary Tables quantify observed conditions based on river systems, such as the combined length of linear features (e.g. shoreline miles surveyed, miles of bulkhead and revetment), the total number of point features (e.g. docks, boathouses, boat ramps) & total acres of polygon features (tidal marshes)

King and Queen County Shoreline Situation Report

The data inventory developed for the Shoreline Situation Reports are based on a three-tiered shoreline assessment approach. This assessment characterizes conditions in the shorezone observed from a small boat moving along the shoreline. Handheld GPS units record data observations in the field. The three tiered shoreline assessment approach divides the shorezone into three regions: the immediate riparian zone, evaluated for land use the bank, evaluated for height, stability, cover and natural protection the shoreline, describing the presence of shoreline structures for shore protection and recreational purposes. Three GIS coverages are generated from the collection technique. They can be downloaded at this site. The GIS coverages use a digitized 1:24,000 scale USGS high water line (HWL) shoreline as the baseline coverage. However, if the position of the digitized HWL differs greatly from the observed shoreline on a 1994 color infra-red digital ortho quarter quadrangle (DOQQ), the shoreline position is corrected to align more closely with the land-water interface observed in the DOQQ. Using ArcInfo, the base shoreline is re-coded with the attributes defined in each coverage. The KQ_lubc coverage are features related to the land use in the riparian zone, and conditions at the bank. The KQ_sstru coverage includes information pertaining to structures for shoreline defense. Finally, KQ_astru identifies structures which are typically built for access and recreational activities at the shore. A metadata file is provided to describe each coverage

Summary Tables: Northampton County, Virginia Shoreline Inventory Report

The Shoreline Inventory Summary Tables quantify observed conditions based on river systems, such as the combined length of linear features (e.g. shoreline miles surveyed, miles of bulkhead and revetment), the total number of point features (e.g. docks, boathouses, boat ramps) & total acres of polygon features (tidal marshes)

Summary Tables: Westmoreland County, Virginia Shoreline Situation Report

The Shoreline Inventory Summary Tables quantify observed conditions based on river systems, such as the combined length of linear features (e.g. shoreline miles surveyed, miles of bulkhead and revetment), the total number of point features (e.g. docks, boathouses, boat ramps) & total acres of polygon features (tidal marshes)