Complete Chain

Prediction of the behavior and persistence of oil in intertidal habitats is based on an understanding of the dynamics of the coastal environments, not just the substrate type and grain size. The intensity of energy expended upon a shoreline by wave action, tidal currents, and river currents directly affects the persistence of stranded oil. The need for shoreline cleanup activities is determined, in part, by the slowness of natural processes in removal of oil stranded on the shoreline. The potential for biological injury, and ease of cleanup of spilled oil are also important factors in the ESI ranking. Generally speaking, areas exposed to high levels of physical energy, such as wave action and tidal currents, and low biological activity rank low on the scale, whereas sheltered areas with associated high biological activity have the highest ranking. The list below includes the shoreline habitats delineated for Puerto Rico, presented in order of increasing sensitivity to spilled oil: 1A) Exposed Rocky Cliffs; 1B) Exposed, Solid Man-made Structures; 2A) Exposed Wave-cut Platforms in Bedrock; 2B) Scarps and Steep Slopes in Muddy Sediments; 3A) Fine- to Medium-grained Sand Beaches; 4) Coarse-grained Sand Beaches; 5) Mixed Sand and Gravel Beaches; 6A) Gravel Beaches; 6B) Riprap; 7) Exposed Tidal Flats; 8A) Sheltered Rocky Shores; 8B) Sheltered, Solid Man-made Structures; 9A) Sheltered Tidal Flats; 9B) Sheltered, Vegetated Low Banks; 10D) Mangroves. In many cases, the shorelines are ranked with multiple codes, such as 10D/6A. The first number (10D, mangroves) is the most landward shoreline type, with gravel beach (6A) being the shoreline type closest to the water. | Description Source: Research Planning, Inc.

Where marshes, bogs, floodplain forests, swamps, and other wetlands are associated with streams, they can add measurably to the biological sensitivity of a stream reach. Many of the more extensive marsh areas of Puerto Rico are found in the coastal zone and are closely associated with the ESI classification rather than the RSI. Though many smaller, low-gradient, streams in Puerto Rico have an abundance of streamside marsh and aquatic vegetation, none of these areas were found along the inland stream reaches mapped during this project. Likewise, none of the remaining coastal Pterocarpus swamps of Puerto Rico were located directly adjacent to the streams mapped (some were mapped as rare habitats, more closely associated with the coastal ESI classification). Though once numerous, almost all of the coastal and lowland Pterocarpus swamps of Puerto Rico have been lost; only a few rare stands remain (Cintron, 1983). Though not often recognized, large portions of the inland mountain areas of Puerto Rico described as wet forest and rain forest are considered forested wetlands (Lugo and Brown, 1988). Specific wetland forest types in montane areas include Sierra palm breaks (palm slope forest), Colorado forest (titi or Cyrilla forest), and cloud forest (dwarf or elfin forest) (Lugo and Brown, 1988). The narrow floodplain forests of Sierra palm that border many montane stream reaches should also be considered wetlands, as would the rare montane Pterocarpus stands (Frangi and Lugo, 1985; Lugo and Brown, 1988). Wetland types associated with floodplain areas would be highly vulnerable and sensitive to spilled oil released into streams, especially during flood events. Unfortunately, due to data limitations, small inland and montane floodplain wetlands could not be adequately mapped during this project, though they are included as an RSI class (RSI = 10). One montane, streamside, Pterocarpus stand was mapped as a rare habitat type on a small tributary (RSI = 9) of the R\xEDo Mameyes (map 26). When floodplain forests and other wetland areas are identified, either by resource experts or during observations in the field, the adjacent stream channel should be considered an RSI = 10 reach (especially during high water or flood conditions). The list below outlines the stream reach classification for Puerto Rico, presented in order of increasing sensitivity to spilled oil: 1) Quiet Pool, Low-sensitive Banks; 2) Straight Channel with Currents, Low-sensitive Banks (Mud Dominant); 3) Meandering Channel, Sand Point Bars; 4) Meandering Channel, Vegetated Point Bars; 5) Rapids over Bedrock; 6) Meandering Channel, Sand and Gravel Point Bars; 7) Split Channels With Coarse Gravel, Some Rapids; 8) Small Falls, Boulders in Channel; 9) Large Falls, Boulders in Channel; 10) Channels with Associated Vulnerable Wetlands. | Description Source: Research Planning, Inc.

Type of geographic feature | Description Source: Research Planning, Inc.

Data source of the ESI arcs | Description Source: Research Planning, Inc.

Regional environment | Description Source: Research Planning, Inc.