Water Level Monitoring and Flood Hazard Emergency

Management in Chesapeake BayJohn D. Boon John M. Brubaker

Virginia Institute of Marine Science

C.R. BerquistDepartment of Geology, College of William and Mary

Should we care about climate

change?

Jamestown Water Levels and Flood Hazard Emergency Management Project

Project Goals:• To provide emergency managers with water

level data in near real-time during tropical storm and hurricane events via the Internet

• Establish a data base of measured water level extremes as an aid to community planning

• Provide water level histories needed to verify numerical models

7 OCT 2006 ‘NORTHEASTER’ www.worldtidesandcurrents.com

Photo courtesy of Dr. David Forrest, VIMS

www.vims.edu/physical/

Jamestown Water Levels and Flood Hazard Emergency Management Project

Project Goals:• To provide emergency managers with water level data

in near real-time during tropical storm and hurricane events via the Internet

• Establish a data base of measured water level extremes as an aid to community planning

• Provide water level histories needed to verify numerical models

Jamestown Water Levels and Flood Hazard Emergency Management Project

Project Goals:• To provide emergency managers with water level data

in near real-time during tropical storm and hurricane events via the Internet

• Establish a data base of measured water level extremes as an aid to community planning

• Provide water level histories needed to verify numerical models

In the coastal zone, extreme flooding is caused by

STORM TIDES

Storm Tide:Sum of a Storm Surge and the

Astronomical Tide

Storm Surge: Water level change due to storm effects (wind, low pressure)

Astronomical Tide: Water rise and fall due to gravity of earth, moon and sun

ERNESTO Storm Surge: 3.56 feet

Storm Tide: 5.51 feet

What a Difference a “Phase” Makes …

September, 2006

8/318/318/318/31 9/19/19/19/1 9/29/29/29/2 9/39/39/39/30000

1111

2222

3333

4444

5555

6666Hampton Roads (Sewells Pt), VA

storm tideastronomical tidestorm surgemmsl (lunar)

2006

‘ERNESTO’

8/318/318/318/31 9/19/19/19/1 9/29/29/29/2 9/39/39/39/30000

1111

2222

3333

4444

5555

6666

Windmill Point, VA

storm tideastronomical tidestorm surgemmsl (lunar)

Water Level (feet above MLLW)

2006

‘ERNESTO’

50 Years of Storm Tides at Sewells Point

1957 – 2006Four Northeasters and a Hurricane

Water levels from U.S. National Oceanic and Atmospheric Administration

Sea Level Change at Hampton Roads, Virginia

1930 - 2005

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1930

1934

1939

1943

1948

1952

1956

1961

1965

1970

1974

1979

1983

1987

1992

1996

2001

Fee

t ab

ove

198

3-20

01 M

LL

W Monthly Mean Sea Level, Hampton Roads (Sewells PT), VA

Sea Level Trend: 1.4 ft/century

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1930

1934

1939

1943

1948

1952

1956

1961

1965

1970

1974

1979

1983

1987

1992

1996

2001

Fee

t ab

ove

198

3-20

01 M

LL

W Monthly Mean Sea Level, Hampton Roads (Sewells PT), VA

Sea Level Trend: 1.4 ft/century

Aug33

Sep03

Sep44Oct54Aug55

Sep60Mar62

Sep99

Water levels from U.S. National Oceanic and Atmospheric Administration

Lower Chesapeake Bay Storm Tide Comparisons‘ERNESTO’ - September, 2006

Northeaster – October, 2006Northeaster – November, 2006

Extratidal High Water (XHW)

A new metric for comparing storm tides

HAT

LAT

HAT

LAT

? ? ?

HAT

LAT

0.83

1.98 feet

HAT

EXTRATIDAL HIGH WATER

LAT

0.83

JAMES RIVER (SEWELLS POINT)

0

1

2

3

4

5

6

Sep-06 Oct-06 Nov-06

EX

TRA

TID

AL

HIG

H W

ATE

R Feet

‘ERNESTO’

RAPPAHANNOCK RIVER (WINDMILL POINT)

0

1

2

3

4

5

6

Sep-06 Oct-06 Nov-06

EX

TRA

TID

AL

HIG

H W

ATE

RFeet

‘ERNESTO’

YORK RIVER (USCG TRAINING CENTER)

0

1

2

3

4

5

6

Sep-06 Oct-06 Nov-06

EX

TRA

TID

AL

HIG

H W

ATE

R

Feet

‘ERNESTO’

November 2006

YORK RIVER (USCG TRAINING CENTER)

0

1

2

3

4

5

6

Sep-06 Oct-06 Nov-06

EX

TRA

TID

AL

HIG

H W

ATE

R

Feet

‘ERNESTO’

2.5

HURRICANES

0

1

2

3

4

5

6

AUG, 1933 ISABEL KATRINA

EX

TRA

TID

AL

HIG

H W

ATE

R

Feet

Work in Progress at Jamestown …

Jamestown water level station