Climate change impacts on Virginia water resources
Carl Hershner
Currently anticipated changesby 2100
• Temperature +2oC to +5oC– more hot days
• Storm frequency?– intensity may increase
• Precipitation – more intense events– more draughts ?
• Sea level +3 to +7 +9 ft
‐1.5
‐1
‐0.5
0
0.5
1
water level relative to NAV
D88
in fe
etSewells Point water level 1970 through 2015
relative to NAVD88
observed water level linear trend mean sea level 1983 ‐ 2001
Relative sea level rise in Virginia
• Global sea level rise (NASA)– Melting ice caps (1.26mm/yr)
– Warming (expanding) ocean water (1.58mm/yr)
– Land water storage (0.32mm/yr)
• Land sinking (USGS)– Isostatic glacial rebound (1mm/yr)
– Local subsidence • Ground water withdraw (0.1 – 3+mm/yr)• Meteor crater sediment compaction (0mm/yr)
• Ocean circulation
Cumulative change in the total mass (in Gigatonnes, Gt) of the Greenland Ice Sheet between April 2002 and April 2015 estimated from GRACE measurements. Each symbol is an individual month and the orange asterisks denote April values for reference. Tedesco et al, 2015. Greenland Ice Sheet, Arctic Report Card: Update for 2015 available at: http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html
Greenland Ice Sheet massmelting ice caps
http://www.ncdc.noaa.gov/indicators/
World ocean heat content ‐ top 700 meters
warming ocean water
glacier
100,000 yrs ago
20,000 yrs ago
today
isostatic glacial rebound
land subsidencedue to
groundwater withdrawals
after Pope and Burbey, 2004
Atlantic MeridionalOverturning Circulation
Sverdrup = 1 million
0
1
2
3
4
5
6
7
8
9
1992 2002 2012 2022 2032 2042 2052 2062 2072 2082 2092
feet abo
ve 1992 level
year
Relative Sea Level Rise for SE Virginiain feet above 1992 level
highest
high
low
historic
2066+2.2ft
2046+1.2ft
2016
Pamunkey River
Hill Marsh
high marsh communityin tidal freshwater
low marsh communityin tidal freshwater
low marsh communityin tidal freshwater
1 ft 2 ft 3 ft 4 ft 5 ft 6 ft 7 ft 8 ft 9 ft 10 ftAccomack County 100 100 100 100 100 100 100Virginia Beach city 20 20 20 20 20Norfolk city 8 8 31 39 54Portsmouth city 25 75 75 75Hampton city 17 17 17 33 33Newport News city 14 29 29 29
Percent of hospitals flooded at these water levels
Climate Central (2014). Sea level rise and coastal flood exposure of Hopitals by County in VA, in Surging Seas Risk Finder. Retrieved from http://ssrf.climatecentral.org/#state=Virginia&level=10&category=Hospitals&geo=County&pt=p&target=&p=S&protection=tidelthresh&folder=Critical
1 ft 2 ft 3 ft 4 ft 5 ft 6 ft 7 ft 8 ft 9 ft 10 ftAccomack County 7.7 7.7 7.7 7.7 15.4 23.1 23.1 23.1 23.1 23.1Virginia Beach city 1.1 1.1 1.1 3.4 5.6 7.9 11.2 18Norfolk city 1.6 3.3 4.9 6.6 9.8 14.8 26.2 42.6Chesapeake city 1.9 1.9 7.5 7.5 7.5 28.3Portsmouth city 3.6 3.6 14.3 17.9 39.3 50Hampton city 5.7 17.1 28.6 34.3 40Newport News city 2 3.9 3.9 3.9York County 5Poquoson city 50 50 100 100 100 100 100Gloucester County 10 10 10 10
Percent of schools flooded at these water levels
Climate Central (2014). Sea level rise and coastal flood exposure of Public Schools by County in VA, in Surging Seas Risk Finder. Retrieved from ssrf.climatecentral.org/#state=Virginia&category=Schools_public&geo=County
Langley Air Force Base
Fort Eustis Army Base
Norfolk Naval Base
Portsmouth Naval Shipyard Oceana Naval Air Station
Fort Monroe
Currently anticipated changesby 2100
• Temperature +2oC to +5oC– more hot days
• Storm frequency?– intensity may increase
• Precipitation – more intense events– more draughts ?
• Sea level +3 to +7 +9 ft
Southeast Temperature: Observed and Projected
Figure source: adapted from Kunkel et al. 2013
Variation in storm frequency and intensity during the cold season (Nov to Mar)
frequency intensity
The intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5) hurricanes, have all increased since the early 1980s.
http://www.chesapeakedata.com/changingchesapeake/
Watershed Implementation Plans
Projected Changes in Water Withdrawals
Figure source: Brown et al. 2013
http://www.chesapeakedata.com/changingchesapeake/
http://www.intechopen.com/books/evapotranspiration
• 77oF to 80.6oF
• +16% ET
evapotranspiration
Trends in Water Availability
Figure source: adapted from Sun et al. 2013
Water Stress in the U.S.
Watersheds are considered stressed when water demand (from power plants, agriculture, and municipalities) exceeds 40% (water supply stress index of 0.4) of available supply. (Figure source: Averyt et al. 20111
September 2002
September 2003
Rappahannock River at Fredericksburg
Walkers Dam on the Chickahominy River
10
9 8
76
5
4
3
2
1
VA Coastal Plain Aquifer Cross‐Section
McFarland & Bruce, 2006
1. sea level is rising2. it’s getting warmer3. a bit more precipitation4. more intense storms5. BMPs underperform6. beneficial uses may
suffer
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