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Full-Text Articles in Engineering

Development Of Digital Bathymetry Maps For Lakes Azuei And Enriquillo Using Sonar And Remote Sensing Techniques, Michael Piasecki, Mahrokh Moknatian, Fred Moshary, Jorge Gonzalez May 2019

Development Of Digital Bathymetry Maps For Lakes Azuei And Enriquillo Using Sonar And Remote Sensing Techniques, Michael Piasecki, Mahrokh Moknatian, Fred Moshary, Jorge Gonzalez

Publications and Research

This article presents an improved algorithm for optimization and development of a digital bathymetric model (DBM) for Lake Azuei (LA) (Haiti) and Lake Enriquillo (LE) (Dominican Republic) using the ANUDEM method. Both sonar data and contour lines of the lakes’ layout extracted using Landsat imagery were compiled for bathymetry development. We show that the performance of the ANUDEM method was strongly dependent on the density and irregularity of the spatial distribution of the data. Changing the resolution of the output grids and deriving auxiliary topographically corrected contours improved the ANUDEM performance and minimized the systematic errors of the method. Statistical ...


Observational Time Series For Lakes Azuei And Enriquillo: Surface Area, Volume, And Elevation, Mahrokh Moknatian, Michael Piasecki Jan 2019

Observational Time Series For Lakes Azuei And Enriquillo: Surface Area, Volume, And Elevation, Mahrokh Moknatian, Michael Piasecki

Publications and Research

In this report, we present historical time series of surface area, volume, and elevation for lakes Azuei (Haiti) and Enriquillo (Dominican Republic). The intention is to present a history of the lakes’ levels for both bodies of water as derived from Landsat imagery that is augmented by reports and narratives that reach further back in time. We also summarize lake level time series data collected and developed through various other efforts and compare these data sets to our time series. The time series contains 45 years’ worth of data ranging from 1972 to 2017 which we developed from Landsat imagery ...


Development Of Geospatial And Temporal Characteristics For Hispaniola’S Lake Azuei And Enriquillo Using Landsat Imagery, Mahrokh Moknatian, Michael Piasecki, Jorge Gonzalez May 2017

Development Of Geospatial And Temporal Characteristics For Hispaniola’S Lake Azuei And Enriquillo Using Landsat Imagery, Mahrokh Moknatian, Michael Piasecki, Jorge Gonzalez

Publications and Research

In this paper, we used Landsat imagery for water body identification to create a novel 36-year surface area extent time series for lakes Azuei (Haiti) and Enriquillo (Dominican Republic) aimed at illuminating the dramatic temporal changes of these two lakes not just at yearly but at monthly or even sub-monthly scales. We used the Normalized Difference Water Index (NDWI) to extract water features and we also used spatial differentiation and thresholding techniques to remove clouds and associated shadows from the scene that were then passed through gap filling algorithms to complete and extract the lake extent polygons. We also explored ...


Shift Towards P Limitation With N Deposition?, K. F. Crowley, B. E. Mcneil, G. M. Lovett, C. D. Canham, C. T. Driscoll Jan 2012

Shift Towards P Limitation With N Deposition?, K. F. Crowley, B. E. Mcneil, G. M. Lovett, C. D. Canham, C. T. Driscoll

Civil and Environmental Engineering

Atmospheric nitrogen (N) deposition is altering biogeochemical cycling in forests and interconnected lakes of the northeastern US, and may shift nutrient limitation from N toward other essential elements, such as phosphorus (P). Whether this shift is occurring relative to N deposition gradients across the northeastern US has not been investigated. We used datasets for the northeastern US and the Adirondack sub-region to evaluate whether P limitation is increasing where N deposition is high at two geographic scales, based on N:P mass ratios. Using a model- selection approach, we determined that foliar N for dominant tree species and lake dissolved ...


Transport By An Intrusion Generated By Boundary Mixing In A Lake, Danielle J. Wain, Chris R. Rehmann Aug 2010

Transport By An Intrusion Generated By Boundary Mixing In A Lake, Danielle J. Wain, Chris R. Rehmann

Civil, Construction and Environmental Engineering Publications

A dye study was conducted to track an intrusion generated at the boundary of a small lake. Persistent turbid layers offshore presented evidence of possible intrusions from boundary mixing. After high winds, a streak of Rhodamine WT was injected at the boundary of the lake where the slope was between 5% and 10%. Both vertical profiles and longitudinal transects of the dye concentration were measured. The three-dimensional dye mapping showed a distinct dye intrusion, ranging between 0.5 and 1 m thick, over 200 m in horizontal extent offshore, 1 day after the injection. Profiles of temperature microstructure measured soon ...


Strategy Of Water Pollution Prevention In Taihu Lake And Its Effects Analysis, Shuqing Yang, P.W. Liu Jan 2010

Strategy Of Water Pollution Prevention In Taihu Lake And Its Effects Analysis, Shuqing Yang, P.W. Liu

Faculty of Engineering - Papers (Archive)

Taihu Lake, the third largest freshwater lake in China, is located in the Chanjiang Delta of the Yangtze River. Its waters are used by agriculture, industry and as major drinking water for several cities including Shanghai and Wuxi. The lake also is important for tourism, aquaculture and flood control. Taihu Lake and its surrounding areas are facing three major water-related threats: deteriorating water quality with inflow and runoff from its watershed; flooding during the rainy seasons; and water shortages during drier months. Noxious algae blooms are occurring with increasing frequency and water quality continues to decline. Remedial actions implemented to ...


Long-Term Trends From Ecosystem Research At The Hubbard Brook Experimental Forest, John L. Campbell, Charles T. Driscoll, Christopher Eagar, Gene E. Likens, Thomas G. Siccama, Chris E. Johnson, Timothy J. Fahey, Steven P. Hamburg, Richard T. Holmes, Amey S. Bailey, Donald C. Buso Oct 2007

Long-Term Trends From Ecosystem Research At The Hubbard Brook Experimental Forest, John L. Campbell, Charles T. Driscoll, Christopher Eagar, Gene E. Likens, Thomas G. Siccama, Chris E. Johnson, Timothy J. Fahey, Steven P. Hamburg, Richard T. Holmes, Amey S. Bailey, Donald C. Buso

Civil and Environmental Engineering

The Hubbard Brook Experimental Forest was established by the U.S. Forest Service in 1955 as a major center for hydrologic research in the Northeast. The Hubbard Brook Ecosystem Study originated 8 years later with the idea of using the small watershed approach to study element flux and cycling and the response of forest ecosystems to disturbance. Since that time, the research program at Hubbard Brook has expanded to include various physical, chemical and biological measurements collected by researchers from a number of cooperating institutions. Collaborative, long-term data are the keystone of the Hubbard Brook Ecosystem Study and have provided ...