High Mountain Soil Stabilization, Guanica Watershed, Puerto Rico, US Territory

Problem

In the high mountains of Guanica, soil was exposed due to a former road being washed out and reconstructed. This area of the watershed receives 80 - 100 inches of rain (>100cm) annually and is a major source area for sediment that is transported through the watershed to the nearshore coral reefs. Sediment runoff from destabilized high mountain soils is a major source of sediment that is transported through the watershed to the nearshore coral reefs. Additional sediment in reef systems blocks sunlight in the water column that the reef needs to survive and degrades critical habitat for species that rely on the reefs.

Solution

Reestablishing vegetation in high mountain soils provides root structures which hold soil together and absorb groundwater. This vegetation also slows rainfall runoff, resulting in higher water infiltration and less overall sediment erosion. Stabilizing high mountain soils in the Guanica watershed is part of a larger effort to implement the restoration plan for the watershed.

Implementation

The technical staff at Ridge to Reefs and Protectores de Cuencas purchased a hydroseeder. Working with experts from the Natural Resources Conservation Service of the United State Department of Agriculture, North Carolina State University, the National Oceanic and Atmospheric Administration, and Fish and Wildlife Service, we developed mulches and seed mixes optimal for encouraging and supporting the growth of natural vegetation cover. The roots of this growth stabilizes steep slopes in the mountains, naturally working with high seasonal rainfall of Puerto Rico.

Outcomes

Stabilization of these soils supports a healthy vegetated ecosystem in the high mountains by preventing additional soil loss. It also prevents sediment from flooding the watershed downstream, protecting the health of the nearshore reefs. Healthy coral reefs protect and support local and migrating species, provide subsistence fishing areas, and support an ecotourism economy. Strong reefs also provide protection to coastal areas, as they naturally attenuate the energy from storm waves which provides a valuable buffer for coastal communities.