Reducing the Vulnerability of Societies to Water Related Risks at the Basin Scale (Proceedings of the third International Symposium on Integrated Water Resources Management, Bochum, Germany, September 2006). IAHS Publ. 317, 2007, 325–329.

Database improvement for better land management and natural disaster prevention in a tropical watershed

JÜRGEN BAUMANN¹, ISIDRO GAYTAN¹, JOSÉ LUIS ARELLANO¹, JOSE LUIS MIRANDA¹ & JUAN ALBERTO RODRIGUEZ²

1 National Water Commission, Av. Insurgentes Sur 2416, Col. Copilco El Bajo, 04340 México, DF, Mexico

jh_baumann@web.de

2 Autonoumus University of State of Chiapas, Faculty for Agricultural Sciences, Campus IV, Estación Huehuetán, 30660 Huehuetán, Mexico

Abstract The Tropical Pacific Coastal Region of the Chiapas State in Mexico is frequently affected by highly erosive rainstorms and rainfall accumulations. A broad database of rainfall intensity and erosivity characteristics and hydrological responses of four micro-catchments under different land-use systems were obtained during a six-year investigation period in the Huehuetán watershed. Overall classification of rainfall data showed that highly erosive single rainstorms contribute considerably to annual rainfall. Major soil types present a great heterogeneity of physical conditions, and soil texture is an important factor for determining runoff behaviour. The effect of slope was compared in two adjacent micro-catchments under coffee production systems. Rainfall erosivity–runoff equations were established for the catchments. The database and the results will allow for the calibration and use of hydrological and erosion models as planning tools for land-use and disaster prevention measures in the tropical watersheds at the Coastal Region.

Key words rainfall erosivity; runoff coefficient; small catchments; slope gradient; soil heterogeneity; tropical watersheds