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Hydrological Disasters

Hydrological Disasters

According to the United Nations Office for Disaster Risk Reduction (UN), hydrological disasters are those that originate from the occurrence, movement, and distribution of surface and subsurface freshwater and saltwater. These violent events are related to the changing and movement of water on and below the surface or in the atmosphere.

A yellow urban building on a street, flooded up to its red awning.
Image Credit: NOAA, “Flooding in Virginia.” https://www.weather.gov/safety/flood-states-va

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Examples of hydrological hazards (as defined by FEMA) include:

  • Floods – “a temporary overflow of water onto land that is normally dry.”[i]
  • Waves and tsunamis – tsunamis are a “series of enormous ocean waves caused by earthquakes, underwater landslides, volcanic eruptions, or asteroids.”[ii]
  • Storm surges – “an abnormal rise of water, generated by a storm, over and above normal tides.”[iii]
  • Other hazards driven by water dynamics, such as mudslides.

Hydrological disasters are also referred to as water-related disasters, which encompasses a water driven event’s

  • Magnitude
  • Frequency
  • Seasonality
  • Characteristics

The hydrological disaster type that Virginia is most at risk for is floods, and the related event types. A flood is an overflow of a large amount of water beyond its normal limit onto land that is normally dry. They occur due to rainfall, snow, coastal storms and surges, and other water systems such as the overflowing of dams. The flood results in a large body of water that spreads out causing damage to buildings and transportation, power outages, and can result in other hazards such as mudslides. Floods can form slowly or very quickly with no warning, such as a flash flood caused by heavy rainfall. [iv]

For more information on Floods and Risk Planning see: https://community.fema.gov/ProtectiveActions/s/article/Flood

Overview of Virginia’s Risk for Hydrological Disasters

Floods are the most common disaster type in the United States, with 90% of natural disasters involving flooding. They can occur during any season across every state, but are more likely to occur in coastal areas, river systems, floodplains, and mountainous areas. The areas at most risk to flooding in Virginia are primarily eastern coastal cities such as Virginia Beach, Norfolk, Hampton, and Chesapeake. However, many towns in western Virginia are also at higher risk of flooding due to their proximity to the Appalachian Mountains and various river systems.

The first documented floods in Virginia were recorded by Virginia colonists in the 18th century; however, it is likely that Virginia Indians had experienced flooding events long before their arrival. The first major flood was recorded on May 27, 1771 when the James River valley in Henrico County flooded 45 feet above the normal level after days of heavy rain, killing an estimated 150 people. The deadliest flood in Virginia occurred August 19-20, 1969 in much of central Virginia. Heavy rains from Hurricane Camille led to the overflowing of many rivers including the James, Rivanna, and Maury, killing 153 people and causing up to $1.2 billion (2024 USD) in damages. The most damaging flood in Virginia occurred November 4-5, 1985 in central and western Virginia. Rains from Hurricane Juan caused flooding in major cities such as Roanoke and Richmond, killing 22 people and around $2.3 billion (2024 USD) in damages. [v]

Government or Organizational Representatives

I am a Local, Regional, or State Government or Organizational Representative: 

Disaster Preparedness

For Local Governments

While some floods occur slowly and can be detected, or may be anticipated due to their association with impending storms, flash floods usually have no early warning and can take only a few minutes to develop. However, there are still actions that Local Government Representatives can do regularly and routinely that can help prepare their community in the event of a flood.

  • Identify, Evaluate, and Document Resources
    • Keep an up-to-date list of all local resources listed in the Virginia Landmarks Register and the National Register of Historic Places, as well as all local easement properties
    • Identify areas or resources that may be most vulnerable to damage from floods
      • Evaluate their needs and consider if there are actions that could reduce their vulnerability to damage from floods.
      • Document their current conditions.
    • Utilize historic resource surveys to document areas or resources before an event strikes. Pre-disaster documentation through historic resource surveys not only provides a locality with an inventory of historic resources, but can provide a point of comparison for post-disaster damage assessments. Include vulnerability assessments as part of the survey to better understand which resources or areas are most vulnerable to threats such as floods.
    • Encourage owners of historic properties to document their properties and engage in regular maintenance/ disaster preparedness actions.
  • Be familiar with your local Hazard Mitigation Plan, and how Cultural and Historic Resources are addressed.
    • Update your locality’s Hazard Mitigation Plan as needed to adequately address Cultural and Historic Resources. This may include:
      • Incorporating National Register, Virginia Landmark Register, and locally designated resources into flood mitigation planning and mapping.
      • Planning and undertaking historic resource surveys. Create a prioritization system to determine survey priorities based on risk.
      • Implement guidelines for flood retrofits and mitigation strategies.
      • Identifying funding opportunities for flood and disaster risk mitigation for vulnerable historic resources.
      • Developing a disaster preparedness and recovery toolkit specific to residents and owners of historic properties.
      • Utilizing existing and/or incorporating new language in your locality’s zoning ordinance that enables exemption or variance requests from FEMA-required flood risk reduction measures for designated historic properties.
        • FEMA’s National Flood Insurance Program (NFIP) permits localities to incorporate relief options for specifically defined historic structures into their ordinances through substantial improvement definition exemptions or variance options; these options are intended to provide relief when typical flood retrofit requirements would be detrimental or ineffectual for an historic structure, they are not intended as blanket exemptions and exceptions. For additional information on historic structures in special floodplain areas and the NFIP, see FEMA P-467-2 National Flood Insurance Program (NFIP) Floodplain Management Bulletin: Historic Structures.
      • Update regional and state cultural resource professional contact list
      • Develop a system for addressing Cultural and Historic Resources post-disaster, such as a priority matrix or tiered system.
For Museums, Cultural Institutions, and Other Organizations

Similar to property owners and local government representatives, staff, volunteers, and board members of cultural institutions and museums, who are responsible for ensuring proper stewardship of their collections and facilities, should evaluate and assess their risk for potential disasters and develop a plan for mitigating potential impacts.

Cultural institutions and museums should take the following steps to prepare for future flooding:

  • Evaluate and assess risk.
    • What are the most at-risk objects or collections? Creating a ranking system for prioritizing protection and implementation of needed retrofits should be considered.
    • Identify if your institution is located in an area at increased risk of flooding, as well as the type of flooding it is at risk for (tidal flooding, flash floods, riverine flooding, etc.).
    • Identify and incorporate any pre-disaster risk mitigation opportunities that may help reduce the impacts of flooding, such as flood barriers, retaining water resistant historic materials, etc. Consult a professional for additional assessments and recommendations.
  • Consider digitizing everything possible to allow for remote access/ visiting if the institution is required to close as the result of a disaster.
  • Develop a plan for budgeting and saving for operational continuity and/or repairs and damages not covered by insurance.
  • Develop a plan, train staff, volunteers and board members of use of the plan, and PRACTICE using the plan. Utilize the resources below to develop your plan.

Disaster Recovery

For Local Governments

After a flood, enact and follow your locality’s Hazard Mitigation Plan and any Emergency Response Procedures. Once it is safe to do so, the following steps can be used to guide you through the disaster recovery process:

  • Follow the direction provided in your locality’s Hazard Mitigation Plan for how to address Cultural and Historic Resources that are damaged by flooding.
    • If your locality’s Hazard Mitigation Plan does not address Cultural and Historic Resources, continue following the recommended steps below.
  • Identify resources that have been damaged by the flooding.
    • This may be accomplished through a survey (conducted by locality staff and/or professional consultants), and/or through property owner submissions
    • Cross reference the list of damaged resources with your locality’s list of historic resources protected by easement and/or listed on the Virginia Landmarks Register and/or the National Register of Historic Places.
  • Create a checklist, or use this sample, to help guide your locality’s actions following a flood.
  • Share information and resources with your community for what to do with their historic properties following a flood.
    • Types of information and resources could include: checklists, recommended professionals, or opportunities for assistance.
  • Identify state/ federal opportunities for disaster recovery assistance for historic resources. Contact DHR and/or submit information using the Disaster Recovery Survey Form.

 

For Museums and Cultural Institutions

In the event of a flood, cultural institutions and museums should follow safety guidelines from their locality and the Virginia Department of Emergency Management: https://www.vaemergency.gov/threats/floods.

Once it has been determined that it is safe to return to your facility, the following steps can be taken to begin the recovery process:

  • Assess the impact and any damage to the facility. Ensure it is safe to access.
  • Document any damage to facility, collections, and/or exhibit spaces.
  • Implement your organization’s Disaster Preparedness and Recovery Plan.

General Resources

See the Virginia Department of Emergency Management’s website for information on what to do during a flood: https://www.vaemergency.gov/threats/floods

State and Federal agencies to contact post-disaster for assistance:

FEMA P-467-2: National Flood Insurance Program (NFIP) Floodplain Management Bulletin: Historic Structures: https://www.nj.gov/dep/hpo/Index_HomePage_images_links/FEMA/FEMA%20historic_structures.pdf

FEMA P-312: Homeowner’s Guide to Retrofitting: Six Ways to Protect Your Home from Flooding: https://www.fema.gov/sites/default/files/2020-08/FEMA_P-312.pdf

FEMA Technical Bulletin 2: Flood Damage-Resistant Materials Requirements for Buildings Located in Special Flood Hazard Areas in accordance with the National Flood Insurance Program: https://www.fema.gov/sites/default/files/2020-07/fema_tb_2_flood_damage-resistant_materials_requirements.pdf

NPS Guidelines on Flood Adaptation for Rehabilitating Historic Buildings: https://www.nps.gov/articles/000/guidelines-on-flood-adaptation-for-rehabilitating-historic-buildings.htm

NCPTT Disaster Preparedness and Recovery of Cultural Resources: https://www.nps.gov/subjects/ncptt/disaster-preparedness-and-recovery-of-cultural-resources.htm

Resources for Museums & Cultural Institutions & Organizations

FEMA 533: Before and After Disasters: Federal Funding for Cultural Institutions: https://www.arts.gov/sites/default/files/DisasterRecovery.pdf

Smithsonian Cultural Rescue Initiative Resources: https://www.culturalrescue.si.edu/resources/preparedness

American Alliance of Museums: Facilities & Operations Resources: https://www.aam-us.org/topic/facilities-operations/

Virginia Association of Museums Disaster Response Resources: https://www.vamuseums.org/disaster-response-resources

dPlan|ArtsReady Emergency Preparedness and Response Tool: https://www.dplan.org/

NPS Museum Handbook, Part 1, Chapter 10: Emergency Planning: https://www.nps.gov/museum/publications/mhi/Chap10.pdf 

Cemetery Disaster Planning (Chicora Foundation, Inc.): http://www.chicora.org/pdfs/Cemetery%20Disaster%20Planning.pdf

Property Owners

I am a property owner:

Is my property designated as historic?

  • Not all old buildings and structures are considered historic. When evaluating if a resource is historic the following criteria are considered:
    • Is the resource at least 50 years old?
    • Does it have integrity of location, design, setting, materials, workmanship, feeling, and association?
    • Does it have significance in history, architecture, archaeology, engineering, and/or culture?
  • Is it individually listed on the Virginia Landmarks Register or National Register of Historic Places?
    • Not sure? Click HERE to search for your property.
  • Is it protected by an historic preservation easement?
    • Not sure? Click HERE for information on easements and how to determine if your property is protected by an historic preservation easement.
  • Is it within a local historic district and/or locally recognized as an historic resource?
    • Not sure? Click HERE to search for your neighborhood, or contact your local officials.

Is there survey data held by DHR on the property?

  • While this does not mean a property is historic, it is useful to know if your property has been part of an historic resource survey. Data from an historic resource survey creates a record of the property’s conditions and known history and can assist with disaster planning and recovery.
  • Not sure? Click HERE to search the VCRIS Map Viewer for your property, or contact VDHR.
  • If you would like to provide information on an unrecorded resource, contact DHR’s Architectural Survey Manager, Mae Tilley: tilley@dhr.virginia.gov; 804-482-6086

 

Disaster Preparedness

Some flood risks may be predictable; however, there are sometimes no advanced warnings for a flood. Regardless, there are still things a property owner can do regularly and routinely that can help prepare their property in the event of a flood.

Depending on the severity of the flood, a range of damage levels may occur to a property. Common types of damage include (but are not limited to):

      Structural Damage or Collapse

Regardless of the level of severity, a building or structure may be at risk of structural damage or collapse as a result of a flood. The level of risk may be dependent on the building’s construction methods and materials, and its condition at the time of the event. Newer buildings must meet certain requirements to help protect them from potential floods, but since older buildings were not required to meet standards like this when they were built, there are changes you can make to help protect your property from flood damage. Additionally, many historic building materials have inherently resilient qualities that, if handled properly, can be salvaged after a flood. An inspection of your historic building can help you determine what actions, if any, should be taken to help protect your property from flood damage. (NOTE: preparedness efforts may not prevent damage).

Most localities with areas at risk of potential flooding will adopt floodplain ordinances with regulations and requirements for structures located in floodplains. FEMA’s National Flood Insurance Program (NFIP) permits localities to incorporate relief options for specifically defined historic structures into their ordinances through substantial improvement definition exemptions or variance options; these options are intended to provide relief when typical flood retrofit requirements would be detrimental or ineffectual for an historic structure, they are not intended as blanket exemptions and exceptions. For additional information on historic structures in special floodplain areas and the NFIP, see FEMA P-467-2 National Flood Insurance Program (NFIP) Floodplain Management Bulletin: Historic Structures. The Virginia Existing Building Code also provides requirements and flexibility for historic buildings in Chapter 9: Historic Buildings. Additional guidance on flood adaptations for historic structures can be found in NPS’ Guidelines on Flood Adaptation for Rehabilitating Historic Buildings. Property owners should consult their local floodplain administrator and other professionals for guidance and recommendations.

A flood may cause structural or aesthetic damage to any of a building’s materials. To ensure historic materials are handled and repaired appropriately, consult the National Park Service (NPS) Preservation Briefs that apply to the damaged material for guidance on preservation best practices: https://www.nps.gov/orgs/1739/preservation-briefs.htm.

 

Mold or Moisture Damage

Mold may grow on almost any surface type when certain conditions are present. Mold growth is triggered by the presence of moisture and may rapidly spread with high humidity and high temperatures. Extended durations of moisture exposure, such as prolonged exposure that may occur during flooding, combined with humidity and temperatures, will also promote mold growth. High water levels can lead to moisture getting into areas that lack waterproofing, such as inside a building, and foster an environment for mold to grow. Additionally, the water itself can damage paint and soften building materials, compromising their integrity.

While older buildings were not required to meet certain standards to help protect them from flooding and reduce mold and moisture damage, many historic building materials have inherently flood resilient qualities that can help them recover after a flood if handled properly. An inspection of your historic building can help you determine what actions, if any, should be taken to help protect your property from mold or moisture damage as a result of flooding. Example steps that can be taken to help reduce the risk of mold or moisture damage after a flood may include:

  • Retaining historic building materials that have inherently flood resilient properties
  • After a flood, ensure there is sufficient airflow and ventilation; materials should not be dried out too quickly, as this may result in additional damage.
  • Remove vegetation and organic materials away from the building
  • Ensure gutters and downspouts are functioning properly, and the site is graded to promote waterflow away from the building. Take actions to correct areas that collect standing water, especially under the building.

To ensure historic materials are handled and repaired appropriately, consult the National Park Service (NPS) Preservation Briefs that apply to the damaged material for guidance on preservation best practices: https://www.nps.gov/orgs/1739/preservation-briefs.htm, and the NPS Guidelines on Flood Adaptation for Rehabilitation Historic Buildings.

Environmental Damage or Erosion

The ground surrounding or beneath a structure may be at risk of damage or erosion as a result of a flood. The large amount of water and strength of the current in a flood can lead to the ground being eroded away extremely quickly. This can result in dangerous terrain forming and compromise the integrity of a building’s foundation, potentially leading to further structural damage. Ground comprised of softer soils, lack of vegetation, and sloped terrain may be at higher risk of erosion and damage from flooding. An inspection of your historic building and its site can help you determine what actions, if any, should be taken to help protect your property from erosion or other site damage that may increase risk of structural damage.

Use the VDHR Disaster Planning Checklist to help prepare your property for disasters.

Although you don’t always have advanced warning of a flood, this checklist could be used for regular/periodic checks of a home to help better prepare it in the event of a flood. It is recommended that property owners complete these checks (including updating supplies and other emergency preparedness actions) at least once a year.

Periodically document the conditions of your property; this will allow for comparisons/repairs/etc. post-disaster if an unanticipated disaster such as a flood.

Inquire with your insurance company about whether a Flood rider is required in addition to your regular insurance. Review your insurance policy annually to make sure you have adequate coverage in the event of a disaster.

Disaster Recovery

In the event of a flood, property owners should follow safety guidelines from their locality and the Virginia Department of Emergency Management (https://www.vaemergency.gov/threats/floods)

Once it has been determined that it is safe to return to your property, the following steps can be taken to begin the recovery process:

  • Contact local officials to inquire about recovery efforts
  • Document damage to your property; if damage is severe, and/or if there are safety concerns, have a professional assess your property and document.
    • Note: health and safety should be prioritized during the recovery process. Return to your property and documentation should occur only if health and safety concerns have been properly addressed. Consult a professional for additional guidance as needed.
  • Use the VDHR Checklist to help guide you through the recovery process.
  • If your property is historic, provide pre- and post-disaster photos and damage information to VDHR by contacting Megan Melinat (melinat@dhr.viginia.gov; 804-482-6455) and/or submit information using the Disaster Recovery Survey Tool
    • If your property is located in a locally-designated historic district, contact local officials to determine whether a certificate of appropriateness is required.
  • Do not throw away any broken/ damaged components of your building/property. These may be able to be repaired, reused and/or referenced to replace materials and features in-kind.
  • Contact your insurance provider to report any damage and file a claim if necessary. Ask about any documentation they require before you begin clean-up or repair work.

Resources

For post-disaster assistance, contact: Megan Melinat (megan.melinat@dhr.virginia.gov; 804-482-6455)

For information about what to do during a flood, visit the Virginia Department of Emergency Management’s website: https://www.vaemergency.gov/threats/floods

Pre-and Post-Disaster Checklists: https://www.dhr.virginia.gov/pdf_files/SandyGrant/Checklists_for_Officials_Homeowners.pdf

FEMA P-467-2: National Flood Insurance Program (NFIP) Floodplain Management Bulletin: Historic Structures: https://www.nj.gov/dep/hpo/Index_HomePage_images_links/FEMA/FEMA%20historic_structures.pdf

FEMA P-312: Homeowner’s Guide to Retrofitting: Six Ways to Protect Your Home from Flooding: https://www.fema.gov/sites/default/files/2020-08/FEMA_P-312.pdf

FEMA Technical Bulletin 2: Flood Damage-Resistant Materials Requirements for Buildings Located in Special Flood Hazard Areas in accordance with the National Flood Insurance Program: https://www.fema.gov/sites/default/files/2020-07/fema_tb_2_flood_damage-resistant_materials_requirements.pdf

NPS Guidelines on Flood Adaptation for Rehabilitating Historic Buildings: https://www.nps.gov/articles/000/guidelines-on-flood-adaptation-for-rehabilitating-historic-buildings.htm

NCPTT Disaster Preparedness and Recovery of Cultural Resources: https://www.nps.gov/subjects/ncptt/disaster-preparedness-and-recovery-of-cultural-resources.htm

[i] FEMA, “Flood,” FEMA Preparedness Community. Accessed July 22, 2024. https://community.fema.gov/ProtectiveActions/s/article/Flood#:~:text=Flooding%20is%20a%20temporary%20overflow,on%20the%20hazard’s%20Information%20Sheet.

[ii] FEMA, “Tsunami,” FEMA Preparedness Community. Accessed July 22, 2024.   https://community.fema.gov/ProtectiveActions/s/article/Tsunami.

[iii] FEMA, “Lesson Summary: Lesson 4,” from “IS-321 Hurricane Mitigation Basics for Mitigation Staff,” (2013). Accessed July 22, 2024. https://emilms.fema.gov/IS321/HM0104summary.html

[iv] United Nations Office for Disaster Risk Reduction, “Hazard,” https://www.undrr.org/terminology/hazard (accessed 31 May 2024); Virginia Department of Emergency Management, “Floods,” https://www.vaemergency.gov/threats/floods (accessed 31 May 2024); Centers for Disease Control and Prevention, “Floods”, https://www.cdc.gov/healthywater/emergency/extreme-weather/floods.html (accessed 31 May 2024), Ready, “Floods”, https://www.ready.gov/floods (accessed 31 May 2024).

[v] Department of Homeland Security, “Natural Disasters”, https://www.dhs.gov/natural-disasters (accessed 31 May 2024); First Street Foundation, “The First National Flood Risk Assessment”, https://assets.firststreet.org/uploads/2020/06/first_street_foundation__first_national_flood_risk_assessment.pdf (accessed 31 May 2024); National Weather Service, “Flooding in Virginia”, https://www.weather.gov/safety/flood-states-va (accessed 31 May 2024); Henrico Country Virginia, “The Flood of 1771”, https://henrico.us/locations/flood/ (accessed 31 May 2024).