ICRAF conducts first water sampling in Layawan Watershed

Research team composed of Professor Moises Dorado from the University of the Philippines Los Baños and Leo Kris M. Palao conducted the first water sampling activity in Layawan Watershed last September 9-13, 2011 for the Ridge to Reef project. Five cross-sections have been selected for the quantification of sediment transport and river discharge along the main river of Layawan Watershed. This water sampling activity is undertaken to measure and record transfer of materials in the river during the start of the rainy season. Sampling sites were located in the localities of Barangay Upper Lancangan, Villaflor Purok 2, Buntawan, Toliyok, and Mialen. Current meter was used to measure flow velocity to quantify river discharge. On the other hand, DH-48 Depth Integrating Suspended-Sediment Sampler and Helley-Smith Hand-Held Bed Load Sampler were used to measure sediment load transport. A bottom-dredge sampler was used to obtain bed materials from each cross section to characterize the initial condition of the streambed at each cross-section.

To gain a deeper understanding on the processes that contributes to sedimentation, ICRAF is planning to construct erosion plots to assess the relative contribution of each land use to erosion vis-à-vis sedimentation. This will provide an avenue to improve existing agricultural and forestry practices to sustain soil and water resources. Moreover, focus group discussion is one of the lined-up activities of ICRAF to assess the various sources that contribute to sedimentation in the watershed, and identify the impact of material transfer to coastal ecosystem.

The result of the study will also contribute to the packaging of environmental payment scheme that will be developed by project 2 (Addressing non-optimal use of resources through valuation and environmental payments). The identification of the material flow from the ridge to the coastal areas will provide basis for the quality of the water as the environmental service to be valued in the PES design. Furthermore, this activity can provide the baseline scenario necessary for any PES scheme as the current status of the Layawan River will be evaluated prior to any proposed land-use change for the sustainability of the PES program. (10/21/2011)