LA HIGHWAY 1 Values and Vulnerabilities. 2011 Update illustrating the Frequency of Inundation over...
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Transcript of LA HIGHWAY 1 Values and Vulnerabilities. 2011 Update illustrating the Frequency of Inundation over...
2011 Update illustrating the Frequency of Inundation over
Louisiana Highway 1between Golden Meadow and
Leeville, LA
Illustrations calculated by NOAAHighway Elevations data by Dr. Roy Dokka
Existing Deepwater Structures in GOM:90% are serviced by Port Fourchon!
LA 1 Toll Road Update January 2010
3 Week Loss of Services of Port Fourchon National Economic Impacts:
• $9.9 Billion in Sales Loss *
• $2.9 Billion in Household Earnings Loss
• $77,440 Jobs Loss Nationally
* Based on $66/barrel Oil
Source: The economic impacts of Port Fourchon on the National and Houma MSA Economies.PREPARED BY: LOREN C SCOTT & ASSOCIATES, February 2008.
Bench Mark “8762084 B 1986” 1.24m
Leeville Station Datum 0.00m
Mean Higher High Water (MHHW) 1.21m
Local Mean Sea Level (MSL) 1.08m
Mean Lower Low Water (MLLW) 0.94m
Tidal Datum Elevations based on 1983-2001 Modified National Tidal Datum Epoch (2002-2006 MSL)
Leeville, LA NOAA Tide Station Bench Mark Elevation Relationship to Tidal and Geodetic Datums using data from 1987-1990
Elevation difference 0.78m
Highest observed water level 3/23/1987 1.53m
NAVD88 (1993) no longer published; LA-1 Average NAVD88 Elevation from Mallory (2011)(Note: There is a high degree of uncertainty in NAVD88 elevations due to ongoing subsidence)
1.56m“5%” Elevation of LA-1 (Golden Meadow to Leeville)
Elevation difference 0.03m
NOAA 2/2011
Estimated NAVD88 (1993) 0.78m
Estimated Effects of RSLR on Frequency and Duration of Inundation for Leeville, LA using observations 1987-1990 and then projecting this 4-year time period forward using
present rate of sea level rise
Using “5%” LA-1 elevation of 0.78m NAVD88 (1993)
Occurrences of Inundation
(over 4-years)Duration of Inundation
(over 4- years)Elevation Rise
Above 1990 MSL
4-yr Time PeriodRSLR rate mm/yr) (# of tides)
(hours (percent of total time)) (meters)
1987- 1990 9.24 0 0 (0%) -2027-2030 9.24 124 960(6%) 0.32047- 2050 9.24 1127 19163(55%) 0.62097- 2100 9.24 1334 33699(96%) 1.0
The elevation of LA-1 will become increasingly inundated even if the present day relative
sea level rise (RSLR) remains constant in the future.
Note: NAVD88 elevations for bench marks and for LIDAR elevations for road surface are only estimates and have significant uncertainty