SEA LEVEL RISE: ONE REGION'S STRUGGLE TO

PLAN FOR A RISING TIDE

Alison Meehan, CFMVirginia Dep’t of Conservation and

Recreation

Agenda

The Problem Examples Discussion

Hampton Roads, Virginia

6 Counties 9 Cities Borders the

Chesapeake Bay

Sea Level Rise

A high rate of subsidence means Hampton Roads has the highest rate of sea level rise on the east coast, totaling 1.45 feet over the last century.

Expected to be one of the worst impacted areas by sea level rise in the country – second only to New Orleans.

Mean Sea Level TrendSewell’s Point, Virginia

An Accelerating Problem

The rate of relative SLR in the mid-Atlantic is accelerating and is projected to range between 2.3 and 5.2 feet higher by 2100.

Most communities in Hampton Roads implement only a 1 foot freeboard.

An Ongoing Problem

The year 2100 is not the finish line! Sea level will continue to rise after that.

Failure to Act

Scientists warned us. It wasn’t until recently that citizens started

to really notice the change.

Now, complaints by citizens force municipalities to mitigate existing infrastructure using short-term fixes – at high costs.

Virginia Beach: Feedback from the Public

80 % - SLR in Virginia Beach is very important and a long-term problem we need to plan for.

53 % - SLR is made worse by humans and we can affect it, for better or worse.

91.5 % - SLR should be a priority for local government.

8 % - Must change their route to work whenever it rains.

2 % - Must change their route to work twice a month with each lunar high tide.

Skip Stiles of a non-profit organization: “Inaction at the state and federal level is leaving Virginians alone, blind and broke to wander across an increasingly dangerous landscape being reshaped by sea level rise."

Virginia Beach: Feedback from the Public

Norfolk: Raising a City

$90 to $180 M projected cost to elevate 2 neighborhoods 

Sea walls, removable flood gates, land purchases recommended. 

Norfolk: Raising a City

Precipitation Flooding Most all of the City of Norfolk’s Planning Districts

experience some level of flooding. Some areas have no curb, gutter, or collection systems Subsequent upstream development exceeds system

capacity

New and replacement storm water infrastructure are designed for 10-year storm.

Tidal flooding exacerbates precipitation flooding –same pipes carrying out rain carry in tide

Norfolk: Rainfall Flooding Success Story

In conjunction with water & sewer replacement full street improvement projects are completed undersized pipes replaced to 10-year design.

Installed drainage inlets, curbs and gutters to improve water flow.

$18.2 million over 10 years.

Over 50 significant storms have effected Portsmouth since the first recorded storm in 1635, averaging one storm every 8 years.

Portsmouth

Portsmouth

Making some steps forward. 18 inch freeboard. SLR mapping.

Portsmouth: Mapping

0-2 feet sea level rise would result in 0.42 square miles being lost

2-4 feet sea level rise would result in 1.16 square miles being lost

4-6 feet sea level rise would result in 2.58 square miles being lost

6-8 feet sea level rise would result 6.05 square miles being lost

Portsmouth: Mapping

Discussion

At which level of government is it best to tackle SLR?

What can be done rather than short-term fixes?

How can anything long-term and proactive be accomplished?

General advice???

Alison Meehan, CFMFloodplain Program Planner

Virginia Department of Conservation and Recreation

(804) 371-6137 Alison.Meehan@dcr.virginia.gov