Rapid Hydrological Appraisal: two case studies in inte- grating knowledge of watershed functions in Indonesia Betha LUSIANA 1.2 , Rudy Harto WIDODO 1 , Meine VAN NOORDWIJK 1 , Elok MULYOUTAMI 1 and Dudy Adi NUGROHO 1 The World Agroforestry Centre - Southeast Asian Programme, Jl. CIFOR, Situ Gede, Bogor, Indonesia; 2 Institute of Plant Production and Agroecology in the Tropics and Subtropics, Garbenstr. 13, Stuttgart, Germany KEY WORDS: hydrological modelling; local knowledge; rapid environmental service assessment; watershed function WHY RAPID HYDROLOGICAL APPRAISAL? Increasing awareness of the importance of maintaining watershed functions has triggered various form of initiatives including providing incentives for people in upper watershed areas to protect watershed functions (Landells-Mills and Porras, 2002). It is known that land use can significantly affect watershed functions such as water quality, water flow, erosion control and sedimentation in downstream areas. However, to develop an effective reward mechanism requires clarity on relations between land use and environmental services that are of sufficient value to become the basis for reward mechanisms (Wunder, 2004). Rapid Hydrological Appraisal (RHA) is a tool that aims to provide such clarity, providing answer on (i) how the watershed function is provided, (ii) who could be responsible for providing this service, (iii) how watershed function is being impacted upon at present, and (iv) how rewards can be channeled to effectively enhance or at least maintain the function (Jeanes et al., 2006). The approach is based on the following activities that can be carried out in less than 6 months: (1) land cover/land use change analysis, (2) exploration of stakeholders’ local knowledge on hydrological functions, water movement and consequences of land use options on the landscape, (3) analysis of existing hydrological data and (4) modelling watershed water balance including scenario analysis of plausible land cover change and their likely impact on watershed functions. APPLICATION OF RHA APPROACH The RHA approach was applied in two contrasting watersheds in Indonesia: Talau watershed, Belu-East Nusa Tenggara and Kapuas Hulu basin, Kapuas Hulu-West Kalimantan (Table 1; Figure 1). Talau is a small watershed located in dry climatic region with strong seasonal difference in rainfall, causing water scarcity problem or low flow during dry season. The landscape water balance (Figure 2) Table 1. Site characteristics of Talau and Kapuas Hulu watershed Site characteristics Talau-Belu Kapuas Hulu Sub-catchment area 720 km 2 9800 km 2 Total rainfall 1600 mm/year 4100 mm/year Main land cover grassland (66%) forest (90%) Water use Farming, household consumption Household consumption, transportation Main issues for local people Scarcity of water for farming and consumption Stable river flow throughout the year for transportation Main issues for policymaker Soil erosion/degradation, water distribution Water quality (impact of mining and logging)