Bryan A. Oakley

Mapping Shallow Coastal Ecosystems: A Case Study of a Rhode Island Lagoon

Abstract In order to effectively study, manage, conserve, and sustain shallow-subtidal ecosystems, a spatial inventory of the basic resources and habitats is essential. Because of the complexities of shallow-subtidal substrates, benthic communities, geology, geomorphology, and water column attributes, few standard protocols are fully articulated and tested that describe the mapping and inventory processes and accompanying interpretations. In this paper, we describe a systematic approach to map Rhode Islands shallow-subtidal coastal lagoon ecosystems, by using, integrating, and reconciling multiple data sets to identify the geology, soils, biological communities, and environments that, collectively, define each shallow-subtidal habitat. We constructed maps for these lagoons via a deliberate, step by step approach. Acoustics and geostatistical modeling were used to create a bathymetric map. These data were analyzed to identify submerged landforms and geologic boundaries. Geologic interpretations were verified with video and grab samples. Soils were sampled, characterized, and mapped within the context of the landscape and geologic boundaries. Biological components and distributions were investigated using acoustics, grab samples, video, and sediment profile images. Data sets were cross-referenced and ground-truthed to test for inconsistencies. Maps and geospatial data, with Federal Geographic Data Committee (FGDC)-compliant metadata, were finalized after reconciling data set inconsistencies and made available on the Internet. These data allow for classification in the revised Coastal and Marine Ecological Classification Standard (CMECS). With these maps, we explored potential relationships among and between physical and biological parameters. In some cases, we discovered a clear match between habitat measures; in others, however, relationships were more difficult to distinguish and require further investigation.

Benthic Geologic Habitats of Shallow Estuarine Environments: Greenwich Bay and Wickford Harbor, Narragansett Bay, Rhode Island, U.S.A

Abstract Oakley, B.A.; Alvarez, J.D., and Boothroyd, J.C., 2012. Benthic geologic habitats of shallow estuarine environments: Greenwich Bay and Wickford Harbor, Narragansett Bay, Rhode Island, U.S.A. An integrated mapping approach using high-resolution side-scan sonar, surface sediment grab samples, digital aerial and orthophotography, and underwater video imagery was used to map Holocene sediment cover and Late Wisconsinan glacial outcrop in two shallow embayments in Narragansett Bay, Rhode Island, U.S.A. The use of side-scan sonar to characterize the seafloor has become common in a variety of different marine environments. Challenges remain in classifying side-scan or other acoustic data into a naming convention that is useful to scientists and managers. We characterize the benthic geologic habitats of these areas utilizing a flexible naming convention that combines information about geologic processes, morphologic form, particle size, biota, and anthropogenic impacts. Benthic geologic habitats were separated into three habitat groups (depositional environments) (estuarine bayfloor, estuarine cove, and estuarine marginal habitats), and further divided on the basis of morphologic form, surface sediment texture, geologic features, biologic characteristics, and anthropogenic impacts. There is a general trend of decreasing grain size with increasing distance from the open water of Narragansett Bay; however, the types and distribution of facies is complicated, and this work adds to the developing sedimentary models of estuaries. The methods outlined in this paper have been successfully applied in other estuarine, lagoon, and shoreface environments, providing a concise method of imaging and characterizing benthic geologic habitats on the seabed.

Mapping the coastal risk for the next century, including sea level rise and changes in the coastline: application to Charlestown RI, USA

A source–pathway-receptor method is used to assess the risk of the coastal community of Charlestown, RI, USA, to the 100-year storm, including effects of sea level rise (SLR) and shoreline/dune erosion. The 100-year storm is simulated using a chain of stochastic and physics-based models combined with a scenario-based approach. Storm surge and wave spectral parameters, obtained from the U.S. Army Corps of Engineers’ North Atlantic Coast Comprehensive Study (NACCS), are used as boundary conditions for high-resolution wave simulations, performed in the coastal and inundation zones using the steady-state spectral wave model STWAVE. Selected scenarios are defined to assess the magnitude of the variability in predicted damage resulting from the uncertainty in SLR, erosion rate, and time at which the 100-year storm would occur. Erosion rates are based on empirical analyses of historic rates of shoreline change, SLR measurements, and coastal erosion theory. The risk is measured in terms of damage to individual houses, based on damage curves developed in the U.S. Army Corps of Engineers, NACCS study. In addition, remediation scenarios are explored, demonstrating that a combination of dune replenishment and an increase in the residential resilience by elevating structures can significantly diminish the risk to the coastal community.

The Block Island Bluff Image Project: Using Google Earth™, Spreadsheet Mapper, and Google Drive™ to Build a Database of Spatially Located Field Images of Coastal Bluffs

ABSTRACT Oakley, B.A.; Manzi, M.A.; Sumeersarnauth, B.J., and Boyle, S., 2017. The Block Island Bluff Image Project: Using Google Earth™, Spreadsheet Mapper, and Google Drive™ to build a database of spatially located field images of coastal bluffs. Spatially located field photography provides a mechanism to gather and share images for the purposes of creating virtual fieldtrips, examining change, and conducting outreach. Uploading images to Google Earth™ or other commercial sites is a common way of sharing images; however, these images are not accessible in a central, organized location, and the spatial control is limited. This paper presents a method of providing quick access to spatially located images using standard equipment (i.e. camera and GPS) and then linking these images to Google Earth using Spreadsheet Mapper, a free tool developed by Google. This technique allows image locations to be shared via a single small >10 kB file, and individual images can be viewed and downloaded as needed. A systematic approach was developed to photograph and mosaic a large number of locations, but this technique could also be applied to individual images (to examine change at one site over time) or to images collected using unmanned aerial systems.