Runoff response and sediment yield of a landslide-affected fire-climax grassland micro-catchment (Leyte, the Philippines) before and after passage of typhoon Haiyan

Jun Zhang, H. J.(Ilja) van Meerveld, Roger Tripoli, L. Adrian Bruijnzeel*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


Decades of logging and slash-and-burn agriculture have turned vast tracts of land in tropical South-east Asia into unproductive fire-climax grasslands whose hydrological functioning is poorly known. To help fill this knowledge gap, a 3.2 ha landslide-affected Imperata grassland micro-catchment with perennial flow on Leyte Island (Philippines) was instrumented and monitored for a year. The area was hit by typhoon Haiyan on 8 November 2013, one of the largest events on record. Landslide surfaces covered 3.4% of the catchment prior to typhoon Haiyan and contributed to ‘direct runoff’ (Qq). This basic ‘contributing area’ increased to 7.7% by activation of old landslides and formation of new ones during typhoon Haiyan. Median storm runoff coefficients (Qq/P) based on straight-line hydrograph separation were 9% and 23% before (48 events) and after the typhoon (43 events), respectively, but the ratios of period-total Qq and P were much larger (24% and 47%, respectively). Both storm runoff volumes and peak discharge increased rapidly once a mid-slope water storage threshold for the upper 60 cm of soil of 250 mm was exceeded. Storm runoff contributions above those generated on landslides were most likely in the form of overland flow given the prevailing very low soil hydraulic conductivities. Post-typhoon water use of the heavily disturbed vegetation was reduced initially by nearly 70%, recovering to nearly 80% of the pre-typhoon value after ∼3 months. The high annual sediment yield (∼27 t ha−1) was heavily dominated by post-Haiyan sediment transport (94%); bedload contributed ∼8% of the total sediment yield.

Original languageEnglish
Pages (from-to)524-537
Number of pages14
JournalJournal of Hydrology
Early online date15 Aug 2018
Publication statusPublished - Oct 2018


Financial support for this work from the China Scholarship Council (to Jun Zhang), VU University Amsterdam, and the Australian Council for International Agricultural Research ( ACIAR Grant no. ASEM/2010/050 to Professor J. Herbohn) is gratefully acknowledged. We thank the leaders of Barangay Basper for their permission to work in the Basper catchment, Mr. José June Bagay for assistance in the field, Miss Ofelia Maranguit and Miss Jertz Escala for help with the laboratory analyses under the supervision of Professor Angela Ferraren (Visayas State University, VSU ). Professor Alfredo Lagmay and Miss Maricar Rabonza of the University of the Philippines kindly provided the DTM-files that enabled the preparation of the catchment map. We are especially grateful to Dr. Antonio Daño (Ecosystems Research and Development Bureau, Laguna) for sharing the unpublished Angat grassland data, and Marc Vis ( University of Zurich ) for help with the HBV-model. Dr. Nestor Gregorio ( ACIAR project and University of the Sunshine Coast , USC ) and Professor Arturo Pasa ( VSU ) are thanked for overall facilitation of the project and Professor John Herbohn ( USC ) for his continuous support. The manuscript benefited from the constructive comments of three anonymous reviewers which is gratefully acknowledged. Appendix A

FundersFunder number
Australian Council for International Agricultural Research
University of Southern California
Research and Development
Valdosta State University
Australian Centre for International Agricultural ResearchASEM/2010/050
University of the Sunshine Coast
Vrije Universiteit Amsterdam
China Scholarship Council
Universität Zürich
University of the Philippines


    • Hillslope hydrology
    • Imperata grassland
    • Landsliding
    • Runoff generation
    • Tropical hydrology


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