ICRAF Publication Detail Page

  • Contact persons
  • Melinda Firds
    Program Management Unit Assistant
    World Agroforestry (ICRAF)
    Jl. CIFOR, Situ Gede, Sindang Barang,
    Bogor Barat - Indonesia 16115
    Tel: +62 2511 8625415
    Fax: +62 2511 8625416
    Email: icrafseapub@cgiar.org

Publication Details

Poster
PO0163-08
TitleDeforestation or Climate Change: What is changing the flow regime of the Way Besai?
AuthorBruno Verbist and Rudy Harto Widodo
Year2008
PublisherWorld Agroforestry Centre - ICRAF, SEA Regional Office
CityBogor, Indonesia
Call NumberPO0163-08
Abstract:
‘Deforestation’ is often perceived to be the cause of loss of watershed functions. The strong association of ‘forest’ and ‘water’ in public perception has very frequently led to conflicts when forest areas were converted to other productive systems. The Way Besai watershed (Sumberjaya) is an example of this, where conversion of forest to coffee gardens on slopes was considered to have led to a reduction of discharge of the Way Besai river, a reducing functionality of the Hydropower plant. This reduced discharge is, in public discourse, attributed to past deforestation and catchment degradation. While the earlier policies of evictions by the Department of Forestry were based on this perception, environmental activists still claim that under-performance of the hydropower schemes of Batutegi (2 X 14 MW) and Way Besai (2 X 45 MW) are due to deforestation of catchment areas, causing shortfalls in the electric power crisis in Lampung province (Oyos Saroso, 2004). By analysis of the long term data records of flow of the Way Besai and rainfall in the area, we explored the possible role of land use change in the catchment versus the alternative explanation of variability (and/or trends) in rainfall as cause of changes in flow. The IHACRES model is a parsimonious (‘few-parameter’) model that has been fitted to data sets derived in various climatic conditions (Croke et al., 2004). Model fits were obtained on the basis of the daily rainfall and discharge data for the1975 – 2007 period. Model parameter sets were derived for each consecutive 3-year period to expose the model to some inter-seasonal variability. All these models were then used on the rainfall data for the whole period 1975-2007. Model parameters for 1975-8 reflect a time that the catchment had 63% forest cover, the model parameters for the last few years a condition with only 13% forest. The results of IHACRES model showed that the impact of annual variation in rainfall on discharge is a factor 4 larger than the possible effects of land use change. The changes in overall catchment hydrology are non-linear with time and may reflect a recovery of vegetation other than ‘forest’. In the public debate, variation and changes in rainfall pattern are insufficiently recognised as major driver of changes in discharge patterns.
Download file(s): Click icon to download/open file.
  File Size Description
download file 648 KB Softcopy
GRP 5: Improving the ability of farmers, ecosystems & governments to cope with climate change
Viewed in 1725 times. Downloaded in 337 times.