Geodynamics

Accurate information about built-up land cover and population density is
essential for sustainable urban growth, especially in lesser developed countries.
Unfortunately, this data is often too expensive for planning agencies, prompting use
of outdated and unreliable information. As a proxy for estimating population density,
a linear regression model is proposed to test the relationship between the percentage
of built-up land cover and vegetation in Pucallpa, Peru. Expert knowledge, low-cost
moderate-resolution sate llite imagery, and high-resolution Google Earth images are
used to estimate the percentage of built-up land cover at randomly assigned reference
locations. Normalized Difference Vegetation Index (NDVI) data, acquired at each
reference point, is the independent variable in a linear regression model constructed
to predict the percentage of built-up land cover. The results were successful, with an
adjusted R2 = 0.774 at 95% confidence. Strength and accuracy are further evaluated
against zoning maps and population estimates provided by local authorities.

Shorelines are a primary source of attraction for the nearly two million tourists who visit Palm Beach County annually. Many of Palm Beach County beaches are located on barrier islands, separated by a series of inlets which serve as access points to the Intracoastal Waterway. However, inlets are often cited as a source of erosion, through interruption of littoral drift and interaction with nearshore hydrodynamics (e.g., causing wave diffraction or refraction). In an effort to mitigate potential negative impacts of the economically important tidal inlets, Palm Beach County has installed a sand transfer plant (STP) at two inlet locations, the Lake Worth Inlet and the South Lake Worth Inlet. Through analysis of annual aerial photography and beach profile surveys taken between 2000 and 2009, this study will determine what effect, if any, these sand transfer plants are having on the inlet-adjacent shorelines north and south of the two inlets with STP, as well as an inlet without an STP (Boca Inlet). This study hopes to increase the understanding of shoreline dynamics in Palm Beach County, which could recognize important alongshore patterns, such as the occurrence of erosional hot spots, to assist in future mitigation efforts.