Dryness Index Study in High Mountain Catchment at Langtang Valley, Nepal Himalaya

Abstract

A simple test of SVAT Model and it’s components is performed to find the dryness index of soil in a High Mountain Catchment, in Langtang Valley,Nepal Himalaya. The details description and application of SVAT model is found in MAet. al. 1999., and was carried out in Kamitani Basin (5km )which is source area of Yura River in the central Japan in 1993 to 1994 and proved that the SVAT model can be used to find the soil condition, the dryness index or wet index of a high mountain basins covered by snow and natural vegetative cover under Humid Climate.Although the geographical position of Langtang Valley is different comparing to Kamitani Basin, but considering other components (high mountain location,snow cover area in winter, Hydrometeorological conditions, monsoon Climate(Rainy summer season) nearly same, I carry out this study to calculate theradiative dryness index using simple formula described as in the SVAT model and its component part to find out the soil index of Langtang Valley by using available Meteoeological (Precipiatation P and Net radiation Q ) Data of1996. Because of the importance of dryness index to the soil parametric information and for the crop production rate over the High Mountain Basins or Valleys of Nepalese Himalaya, the part of equation of the SVAT model is used and compared with our investigated results and found similarities in quantitative values. Therefore, it is applicable in High Mountain Basins in Nepal Himalaya, in order to find out soil dryness index under Monsoon Climatic Condition.