The study documented the impact of Hugo on recreational beaches, particularly in the San Juan area, where historical beach-profile measurements were available. A second field study examined the impact of Hugo on a large offshore sand and gravel deposit, the Escollo de Arenas, a deposit of significant economic potential for Puerto Rico. In a corollary study, USGS scientists investigated the effect of storm events on sediment of the shallow insular shelf in order to assess the amount of nearshore sand and gravel supply and to determine the fate of sand eroded from the shoreline. A fourth study documents the effects of Hugo on coral reef complexes around the island of Culebra. Corals in Puerto Rico and elsewhere are important because the reefs are a source of carbonate sand production, buffers to storm-wave induced coastal erosion, sites of high biologic productivity, as well as tourist attractions.
USGS studies indicate that shorelines have recovered to pre-Hugo conditions.
Long-term accretionary trends have occurred within embayments between headlands in the San Juan area where there are few engineering structures impinging the coastal zone, whereas slightly erosional trends have occurred at headlands. Thus, USGS scientists have documented the apparent long-term trend of shoreline straightening through headland erosion and embayment infilling. During the passage of Hugo, damage to beaches occurred as a result of elevated water levels through a combination of storm surge, wave setup, and wave swash. The typical beach profile change was one of a general flattening shaped by erosion of the upper beach and deposition on the lower beach. The net effect of Hugo on sandy beaches appeared to be one of beach-face erosion with eroded sediment transported both seaward and landward away from the beach face.