Process_Description:
A single geodatabase (GDB) and feature class was created to digitize the shoreline for 2010. Subtypes and domains were used to increase the quality of the shoreline classification.
For the 2010 shoreline, orthophotos were downloaded from the website NOAA Digital Coast Data Viewer. The tile index file was used to download each of the images (2009-2010 USACE NCMP 4-Band 8 Bit Imagery). Areas that were not covered by the 2010, the 2006-2007 Orthophotos were used digitize the shoreline. The total shoreline digitized using the 2006-2007 and 2009-2010 orthophotos was 2% and 98%, respectively.
The main island of Puerto Rico was digitized in different sections: North East, South East, North West and South West. For Vieques and Culebra, the digitization was conducted per municipality.
The land cover and the benthic areas were used to understand the shoreline areas. To best classified the shoreline, different datasets were used as reference: land cover and benthic areas. Also, the DEM was collected to calculate the Slope. This helped to identify cliff areas in the classification.
The digitizing scale was at 1:500. The digitization was conducted clockwise. The digitized line was continuous line with their respective exceptions (rocky barrier, sand bars, etc). When digitizing the type of coast termed "Beach," the high-water line (HWL) will be used as a proxy (Boak and Turner, 2005). If the HWL is not visible, the shoreline proxies will be digitized following this order: Wet/Dry Line or Run Up Maxima, Groundwater Exit, Instantaneous Line.
To merge the digitization and avoid overlaps, transition line features were made when each person finished their assigned classification.
Digitization Decisions: Summary
The main requirement to classify the shoreline features was to answer the question: “What is in contact with the highest water level?” Using this information, the shoreline was digitized as beach, concrete forms, vegetation, and others described in the attribute information. However, the variability of Vieques and Culebra's coasts do not make it possible to answer this question with a single answer for each type of coastline. Therefore, some decisions were taken to homogenize the digitization of the Puerto Rico Main Island, Vieques, and Culebra. One of the goals was to digitize a continuous line describing the coastal areas and the shoreline. Some exceptions were considered when digitizing rocky barriers, vegetation formations in the ocean such as mangroves, and rock formations off the coast. This summary was generated mainly from the inconsistencies that were found during the digitization process.
Beach
High Water Line
In beaches with coarser grain size, the HWL was defined following the line of sediment accumulated along the beach. For this analysis, the benthic layers (2000-2002 Benthic Habitat) helped to identify features like coral reefs and understand the granulometry of the beach. When bluff areas were seen, the HWL was digitized in the color contrast between the bluff and beach berm. If the HWL was not visible, areas with shadows were classified as “No Visibility>Shadows”
When the HWL was not visible, and sand accumulation was seen in the shoreline, other proxies were digitized: instantaneous line, wet/dry line, or groundwater exit point. For beaches with terrigenous sand, the HWL was identified by the highest contrast between wet and dry areas.
Tombolo sand formations were digitized using the instantaneous line or HWL indicators if visible.
When sargasso was present, the continuous line of sargasso accumulated around the last highest tide mark was digitized, avoiding sargasso deposited by a storm or extreme event.
Rocky
The coast is characterized as rocky when water is observed to impact the rock. The instantaneous lines were digitized in the Rocky formation.
The DEM for 2015-2017 was used to calculate the slope in the coastal areas in order to classify the cliff areas. Areas with a slope greater than 40 degrees digitized as “CLIFF.” However, some cells between "cliff" areas could be 20 degrees. In cliff areas where the instantaneous line was seen on the ocean side, the area was digitized as "Bare Land" with a description of "Rocky land." For the shoreline type of "Rocky," the area can have a description of "Cliff," "Bare Land” or "Rocky Barrier."
Rocky areas off the coast within a 300 meters buffer of the shoreline were digitized as “Bare Land” or “Cliff.”
The slope information and Google Earth were used to help distinguish the vegetated shoreline amongnst rocky areas.
Rocky Barriers
The rocky barriers were identified as areas where rocky land and sandy beaches were divided by water. This feature was classified as a reference for further shoreline change analysis. To identity rocky barriers, the benthic layers helped to identify features like coral reefs. Pocket beaches mostly between rocky areas were mostly digitized using the instantaneous line proxy.
Anthropogenic
Marina areas like boating docks were digitized up to 500 meters inland of the shoreline area.
Tourism areas were classified using other sources such as Puerto Rico Land Cover 2010. When no information was available, the concrete forms were classified as “Housing.”
Vegetation
To classify the vegetation, the land cover classification was followed.
In small sandy areas around mangroves, the HWL was digitized to capture sand accumulation.
No Visibility
Palms trees or shadows created by them were classified as “Shadows.” In cases where areas mostly shadows were present, even small sections of the HWL were digitized if visible. If the HWL or any other indicator was not visible, it was classified as "Other." When no orthophoto was available, the area was classified as "Not Surveyed."
In areas where the HWL was not visible, but sand accumulation was seen, other proxies were digitized: instantaneous line, wet/dry line, or groundwater exit point.
Hard Structures
When multiple hard structures were seen, it was classified as “Multiple Structures.” For example, when mitigation structures and construction filling areas were seen, it was classified as “Multiple Structures." Rip-rap covered by water was also digitized if visible.
Other Considerations
River mouth areas were digitized up to 500 meters inland and where some of the water or vegetation connect the shoreline area.
The sandy areas around the river mouth were digitized as HWL.
If a continuous beach was seen along the river mouth areas, the river mouth was not digitized.
Source_Used_Citation_Abbreviation: 2015-2017 USGS Lidar DEM Puerto Rico
Source_Used_Citation_Abbreviation: 2000-2002 Benthic Habitat
Source_Used_Citation_Abbreviation:
Sargassum and Beach Erosion: Potential Costs and Benefits for Coastal Managers
Source_Used_Citation_Abbreviation: Puerto Rico Land Cover 2010
Source_Used_Citation_Abbreviation: 2009-2010 USACE NCMP 4-Band 8 Bit Imagery
Source_Used_Citation_Abbreviation: 2009-2010 Orthophoto
Source_Used_Citation_Abbreviation: 2006-2007 Orthophoto
Process_Date: 20200101
Source_Produced_Citation_Abbreviation: Shoreline of Puerto Rico Main Island, Vieques and Culebra 2010
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
Coastal Research and Planning Institute of Puerto Rico (CoRePI-PR), Graduate School of Planning, UPR-RP.
Contact_Person: Loderay Bracero Marrero
Contact_Position: Research Assistant Lead
Contact_Address:
Address_Type: mailing and physical
Address: Station 1001
City: San Juan
State_or_Province: Puerto Rico
Postal_Code: 00925
Country: Puerto Rico
Contact_Voice_Telephone: 787764000, ext. 85118 or 85119
Contact_Electronic_Mail_Address: loderay.bracero@upr.edu; coastal.planning@upr.edu