fairfax county mt. vernon climate change presentation

8/9/2019 Fairfax County Mt. Vernon Climate Change Presentation

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Adaptationto

Climate Change

Fairfax County Board of SupervisorsEnvironmental Committee

March 6, 2009


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Board Assignment

Create a plan to incorporate climate changeinto the Countys long range planning,

including but not limited to, floodplaindelineation and building requirements inareas that will be affected by sea level rise.

Report to the Boards EnvironmentalCommittee.


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The Players

Local

State RegionalNational

International

COG Climate ChangeProgram

Regional

Sustainable Shorelines andCommunity Management Project


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Major Reports

http://www.mwcog.org/http://www.ipcc.ch/


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Major Reports


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Major Reports

http://www.deq.virginia.gov/info/climatechange.html http://www.chesapeake.org/stac/


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Issues

Time Horizon for Planning

What Sea-level Rise to Plan for

Certainty of Available Information

What Impacts need to be Addressed in Near Term


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Sea Level Rise

Governors Commission Estimate

YR 2050 --- 1.0 - 1.6 ft. (0.3 - 0.5 m) [Interpolated]

YR 2100 --- 2.3 - 5.2 ft. (0.7 - 1.6 m)

Current rate of sea level rise at Washington D.C. Tide

Gage 3.13 + 0.21 mm/yr [Zervas, C.; NOAA; 2001]

YR 2050 --- 0.48 0.56 ft. (0.16 - 0.17 m)

YR 2100 --- 0.96 1.10 ft. (0.31 - 0.33 m)


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Impacts

Rising water levels will convert tidal wetlands to open water andadjoining low lying forested areas to wetlands (Dyke Marsh).

Shoreline erosion along estuaries will result in a loss of land orhardening by property owners to protect land eliminating intertidalwetlands and beaches.

As seal level rises, coastal flooding will become more frequent.

In some older communities, high tides during new and full moonswill flood areas that currently do not flood (New Alexandria).

Increase in annual rainfall (11%).[Governors Commission on Climate Change Final Report; 2008]

Change in the frequency of severe storms.


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Areas Vulnerable to Impacts of Sea Level Rise

Areas Inundated at Elevation 5.0 ft. (shown In red)


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Areas Vulnerable to Impacts of Sea Level RiseCameron Run, Bell Haven & New Alexandria



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Areas Vulnerable to Impacts of Sea Level RiseNew Alexandria



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Areas Vulnerable to Impacts of Sea Level RiseLittle Hunting Creek



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Areas Vulnerable to Impacts of Sea Level RiseLittle Hunting Creek (upper portion)



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Areas Vulnerable to Impacts of Sea Level RiseGunston Manor & Hallowing Point



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Vulnerable Public Facilities

New Alexandria Tide Gate andPumping Station

Lower Potomac Treatment Plant


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Governors Commission

Key Recommendations(Implementation of Action Plan)

Establish a Sub-Cabinet on Climate Change Response.

Secretary of Natural Resources should lead an inter-

agency and intergovernmental effort to develop a SeaLevel Rise Adaptation Strategy by January 1, 2011.

General Assembly should, with the assistance of theVirginia Municipal League (VML) and the VirginiaAssociation of Counties (VACo), undertake a review ofauthorities of local governments, and enact any enabling

authority that is needed.


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Key Recommendations(Implementation of Action Plan)

Local governments should include projected climatechange impacts, especially sea level rise and stormsurge, in comprehensive plans and land use plans and

revise zoning and permitting ordinances to requireprojected climate change impacts be addressed.

State agencies and local governments should developclimate change adaptation plans for criticalinfrastructures for which they are responsible.


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Key Recommendations(Transportation & Infrastructure)

Secretary of Transportation should ensure that climatechange impacts, particularly sea level rise and stormsurge vulnerability in coastal areas of Virginia, are taken

into account in all transportation projects.

Require that all infrastructure projects receiving statefunding are designed to be resistant to climate changeimpacts over the projected life of the project andestablish policies that discourage expenditure of publicfunds on development of public infrastructure in areas

highly vulnerable to climate change effects.


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Key Recommendations(Floodplain Management)

DCR should revise the Virginia Floodplain ManagementPlan and update model floodplain managementordinances to address more specifically sea-level rise

and increasing storm surge impacts due to climatechange.

Direct local governments to update floodplain ordinancesand maps to incorporate sea-level rise and increasingstorm surge impacts where applicable.


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Key Recommendations(Shoreline Management)

Virginia Marine Resources Commission (VMRC) shouldadopt shoreline protection policies that emphasize theuse of living shorelines and seek to avoid shoreline

hardening (bulk heads, sea walls, rip rap) whereverfeasible.

Require local governments to develop integratedshoreline management plans in coordination with VMRC.


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Key Recommendations(Shoreline Management)

DCR should assess the need to expand VirginiasResources Protection Area buffer designations beyondthe current 100-foot requirement to accommodate theimpact of sea level rise.

State and local agencies should establish policies suchas rolling easements, tax incentives, or mandatory

setbacks to discourage new development in vulnerablecoastal areas.


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Key Recommendations(Data & Information Resources)

The General Assembly should provide funding for theVirginia Geographic Information Network to acquire andprocess LiDAR data for the entire state. LiDAR datashould be first acquired for the coastal zone, which will

cost approximately $6 million, and then for the rest of thestate. The resulting data should be made available to allpublic agencies.

Persons purchasing or developing property in vulnerablecoastal areas or floodplains should have ready access toaccurate data on the current and potential futurevulnerability of their property.


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Staff Recommendations

Base adaptation strategy on YR 2050 projection of a 1.0 - 1.6 ft.rise in sea level.

Incorporate sea level rise in the design of all new buildingsrequiring SE approval.

Evaluate the impact of sea level rise during the design of plannedflood protection projects in coastal areas.

Investigate larger freeboard and/or setback for proposedconstruction in areas influence by tidal flooding (Zoning OrdinanceAmendment).

Inventory public facilities in vulnerable areas and evaluateimpacts.

Acquire tools to perform a more detailed analysis of impacts ofsea level rise on floodplain elevations in coastal areas.

fairfax county mt. vernon climate change presentation

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