Dec 02

Publication | Sea level rise, land use, and climate change influence the distribution of loggerhead turtle nests at the largest USA rookery (Melbourne Beach, Florida)

MEPSJ.S. Reece, D. Passeri, L. Ehrhart, S.C. Hagen, A. Hays, C. Long, R.F. Noss, M. Bilskie, C. Sanchez, M.V. Schwoerer, B. Von Holle, J. Weishampel, S. Wolf (2013). “Sea level rise, land use, and climate change influence the distribution of loggerhead turtle nests at the largest USA rookery (Melbourne Beach, Florida).” Marine Ecology Progress Series, 493, 259-274, doi:10.3354/meps10531

Anthropogenic climate change adds to the existing suite of threats to species, such as habitat degradation, by increasing extinction risk and compromising the ability of species to respond adaptively to these stressors. Because threats from anthropogenic climate change often interact synergistically with other threats, integrated assessments of the factors and processes that affect species persistence and distribution are required. We assessed the influence of coastal land use and climate change (specifically sea level rise) on the spatial distribution of nests within the largest loggerhead Caretta caretta marine turtle rookery in the Atlantic Ocean, at Melbourne Beach, Florida, from 1986 to 2006. We generated a multiple regression model based on climate change, sea-level rise and land use that describes 47% of the spatial variation in loggerhead nesting. Nests have shifted northward (likely in response to warming temperatures), away from intensive coastal development, and, surprisingly, toward areas of increased erosion. Using the Bruun Rule (an approximation of the response of the shoreline profile to sea level rise), we modeled the impacts of sea level rise of 0.25 and 0.5 m in conjunction with extrapolations of coastal development and a continued northward shift in nest distribution. We project up to a 43% decrease in beach area from 1986 to a future with 0.5 m of sea level rise and predict that loggerhead nesting will shift northward and become increasingly crowded on narrowing beaches. An implication of this study is that areas currently protected for large rookeries may not overlap with their future distributions.

Permanent link to this article: http://www.mattbilskie.com/sea-level-rise-land-use-and-climate-change-influence-the-distribution-of-loggerhead-turtle-nests-at-the-largest-usa-rookery-melbourne-beach-florida/

Nov 27

Climate and Hydrologic Analysis of Silver Springs, FL

SS-Aerial-DEM-RainQ-PETCourse Project: Climate and Hydrologic Analysis of Silver Springs, FL

The once popular vacation destination in north Central Florida has experienced a decline in spring discharge since the mid-1980s.  A dramatic drop in discharge was observed around the turn of the millennium, and the spring, 12 years later, has yet to recover to pre-2000 conditions.  This study models the inter-annual hydrologic cycle, including a change in storage, using the Budyko framework based on the equity principle to determine the cause of the drop in discharge.  The drop in discharge can be attributed to both climate and human impacts, but the analysis shows that severe drought conditions in 1998 to 2001 is the major contributing factor of the decline of the springshed discharge.  The spring has yet to rebound to pre-2000 conditions because some of the physical characteristics of the springshed were naturally changed and were highly sensitive to the severe drought conditions.

Download Presentation Files (PDF)

Permanent link to this article: http://www.mattbilskie.com/climate-and-hydrologic-analysis-of-silver-springs-fl/

Nov 25

Hydraulic Engineering Guest Lecture – Introduction to Lidar

Bilskie-Intro-to-Lidar-CWR5205Guest Lecture for CWR 5205 at the University of Central Florida

Introduction to Lidar: Applications In Engineering

Nov. 25,2013

Download Lecture Notes (PDF)

Permanent link to this article: http://www.mattbilskie.com/hydraulic-engineering-guest-lecture-introduction-to-lidar/

Oct 17

EWRI Central Florida Branch Luncheon

Pascagoula-DEM-TiltM.V. Bilskie, S.C. Hagen, S.C. Medeiros, D. Passeri, D. Cogging, “Tide, Surge, and Wave Modeling in the Northern Gulf of Mexcio: Development & Application.” Central Florida EWRI October Luncheon, Orlando, FL, October 17, 2013.

Permanent link to this article: http://www.mattbilskie.com/presentation-ewri-central-florida-branch-luncheon/

Sep 19

NOAA Invites Professor To Speak About Climate Change

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“A University of Central Florida professor is one of only eight scientists and engineers in the nation who has been asked to present his findings Oct. 1 at the National Oceanic and Atmospheric Administration’s Science Day to educate the public about the potential impact of climate change.

Engineering professor Scott Hagen will talk during the “Advancing Climate Science for a Climate-Smart Nation” segment of the program that will include a webinar that scientists and policy makers can view.” UCF Today

Continue for the full article…

Permanent link to this article: http://www.mattbilskie.com/noaa-invites-professor-to-speak-about-climate-change/

Sep 09

Marsh Organ Harvest – Grand Bay, MS

GrandBayMarshHarvest

A team lead by Professor Morris from the University of South Carolina and Dr. Medeiros from the University of Central Florida, along with research associates, graduate, and undergraduate students traveled to Grand Bay, MS to harvest marsh organs.  The experiment is used to determine how different specious of salt marsh (Spartina alterniflora & Juncus) respond to growing at different elevations.  In addition, several high-accuracy GPS points were recorded along with several sediment cores within the Grand Bay salt marsh.  Thanks to the great people at the GBNEER (Grand Bay National Estuarine Research Reserve) for their hospitality!

Permanent link to this article: http://www.mattbilskie.com/marsh-organ-harvest-grand-bay-ms/

Aug 27

Hydrodynamic Modeling of Tides and Hurricane Storm Surge for Pre- and Post-Dredging Conditions in the Lower St. Johns River, Florida

LSJR-LULC-ChannelM.V. Bilskie, “Hydrodynamic Modeling of Tides and Hurricane Storm Surge for Pre- and Post-Dredging Conditions in the Lower St. Johns River, Florida.” ASCE COPRI PORTS ’13, Seattle, WA, August 25-28, 2013.

The United States Army Corps of Engineers (USACE), Jacksonville District, is conducting a study for improving navigation near Jacksonville Harbor in the lower St. Johns River (SJR), Florida. A two-dimensional hydrodynamic model (ADCIRC) of the SJR is employed to study the effects that deepening the channel may have on circulation within the river. Model results from an inlet-based modeling domain, forced with astronomic tides, show low sensitivity to mean low water (MLW) and mean high water (MHW) between pre and post-dredging conditions. Results from a large-scale hydrodynamic model (ADCIRC+SWAN), forced by astronomic tides and winds from Hurricane Dora, show minimal difference in peak surge, timing of peak surge, and inundation area. The model is then used to determine possible impacts a 30 cm rise in sea level may have on flooding. Model results demonstrate that peak surge elevations do not increase by the rise in sea level, depicting the dynamic nature of the estuary.

Permanent link to this article: http://www.mattbilskie.com/hydrodynamic-modeling-of-tides-and-hurricane-storm-surge-for-pre-and-post-dredging-conditions-in-the-lower-st-johns-river-florida/

Aug 27

PORTS ’13 – Seattle, WA

timucuanM.V. Bilskie, “Hydrodynamic Modeling of Tides and Hurricane Storm Surge for Pre- and Post-Dredging Conditions in the Lower St. Johns River, Florida.” ASCE COPRI PORTS ’13, Seattle, WA, August 25-28, 2013.

Abstract: The United States Army Corps of Engineers (USACE), Jacksonville District, is conducting a study for improving navigation near Jacksonville Harbor in the lower St. Johns River (SJR), Florida. A two-dimensional hydrodynamic model (ADCIRC) of the SJR is employed to study the effects that deepening the channel may have on circulation within the river. Model results from an inlet-based modeling domain, forced with astronomic tides, show low sensitivity to mean low water (MLW) and mean high water (MHW) between pre and post-dredging conditions. Results from a large-scale hydrodynamic model (ADCIRC+SWAN), forced by astronomic tides and winds from Hurricane Dora, show minimal difference in peak surge, timing of peak surge, and inundation area. The model is then used to determine possible impacts a 30 cm rise in sea level may have on flooding. Model results demonstrate that peak surge elevations do not increase by the rise in sea level, depicting the dynamic nature of the estuary.

Permanent link to this article: http://www.mattbilskie.com/ports-13/

Jul 28

US Congress on Computational Mechanics (USNCCM12)

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M.V. Bilskie, S.C. Medeiros, S.C. Hagen, “Development of a High-Resolution Tide-, Wind-, and Wave-Driven Ocean Circulation Model for the Northern Gulf of Mexico.” 12th International Congress on Computational Mechanics, Raleigh, NC, July 22-25, 2013.

Abstract:The northern Gulf of Mexico is a complex hydrodynamic system including low-lying topography and networks of rivers, bays, marshlands, the Intracoastal Waterway system, along with a wide and flat continental shelf. The intricate geometry creates an interesting scenario for studying sea level rise and hurricane storm surge. To capture the hydrodynamic response to sea level rise and hurricane storm surge, a large-scale, high-resolution wind-wave, tide, and hurricane storm surge model was developed that incorporates a tightly coupled shallow water coastal circulation model and wind wave model (ADCIRC+SWAN). With any coastal inundation model, the overland topography and frictional parameterizations are crucial to the simulated hydrodynamics. Sub-scale terrain features were incorporated into an unstructured finite element mesh and elevations were assigned from interpolating lidar- and survey-derived digital terrain models using a cell averaging method to minimize vertical errors in elevation (Bilskie and Hagen, 2013).

In addition, surface roughness parameters (i.e. Manning’s n, surface canopy, and surface directional effective roughness length [Z0]) were generated from an enhanced parameterization scheme that uses lidar point cloud data to augment look-up tables based on land cover databases. The preliminary finite element mesh contains ~4 million nodes and provides full coverage from the Bay of St. Louis, MS to Apalachee Bay, FL. Mesh resolution in the Gulf is near 5 kilometers, 1 kilometer on the continental shelf, 100 meters along the shoreline, and down to 40 meters in marsh regions and small channels.
Validation consisted of two historical events, Hurricane Katrina and the Deepwater Horizon oil spill (DWH). Hurricane Katrina was simulated and results were compared to observed water levels and recorded high water marks. Simulated inundation area for the DWH was compared to satellite-based observations of the inundation area from processed SAR (synthetic aperture radar) imagery (Medeiros, et al., 2012).

REFERENCES

Bilskie, M. V., and Hagen, S. C. (2013). “Topographic Accuracy Assessment of Bare Earth Lidar-Derived Unstructured Meshes.” Advances in Water Resources, 52, 165-177.
Medeiros, S. C., Hagen, S. C., Chaouch, N., Feyen, J. C., Temimi, M., Weishampel, J. F., Funakoshi, Y., and Khanbilvardi, R. (2012). “Assessing the Performance of a Northern Gulf of Mexico Tidal Model Using Satellite Imagery.” Coastal Engineering, In Review.

 

Permanent link to this article: http://www.mattbilskie.com/us-congress-on-computational-mechanics/

Jul 25

Publication | Topographic Accuracy Assessment of Bare Earth lidar-derived Unstructured Meshes

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M.V. Bilskie, S.C. Hagen (2013). “Topographic Accuracy Assessment of Bare Earth idar-derived Unstructured Meshes.” Advances in Water Resources, 52, 165-177,http://dx.doi.org/10.1016/j.advwatres.2012.09.003

This study is focused on the integration of bare earth lidar (Light Detection and Ranging) data into unstructured (triangular) finite element meshes and the implications on simulating storm surge inundation using a shallow water equations model. A methodology is developed to compute root mean square
error (RMSE) and the 95th percentile of vertical elevation errors using four different interpolation methods (linear, inverse distance weighted, natural neighbor, and cell averaging) to resample bare earth lidar and lidar-derived digital elevation models (DEMs) onto unstructured meshes at different resolutions. The results are consolidated into a table of optimal interpolation methods that minimize the vertical elevation error of an unstructured mesh for a given mesh node density. The cell area averaging method performed most accurate when DEM grid cells within 0.25 times the ratio of local element size and DEM cell size were averaged. The methodology is applied to simulate inundation extent and maximum water levels in southern Mississippi due to Hurricane Katrina, which illustrates that local changes in topography such as adjusting element size and interpolation method drastically alter simulated storm surge locally and non-locally. The methods and results presented have utility and implications to any modeling application that uses bare earth lidar.

Permanent link to this article: http://www.mattbilskie.com/topographic-accuracy-assessment-of-bare-earth-lidar-derived-unstructured-meshes/

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