Estimation of Water Budget in Kathmandu Valley, Nepal
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Journal Title
Journal ISSN
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Department of Hydrology and Meteorology
Abstract
Water is essential to every human community and is essential resources for
economic development, agricultural productivity; industrial growth etc. Of all
the resources of water the primary source of water is the rain. The rainwater will
recharge the ground water and the remaining water will transformed as surface
flow.
Many studies related to hydrology and meteorology were carried out in the
Katmandu Valley. Most of those studies are discharge calculation and rainfall
variability. However there is still lack in the studies of variability of water
surplus and water deficit within the valley. Therefore the main purpose of my
study is to estimate the water balance components. Thornthwaite method is
applied for this purpose. In this study of water budget, seven stations are taken
and water balance components are found to be different for each station.
Kathmandu Valley receives 1819 mm of annual rainfall. During monsoon season
it receives about 1461 mm amounting about 80% of annual value while in premonsoon
season,
post-monsoon
season
and
winter
season
it receives about 237
mm (13%), 68 mm (4%) and 53 mm (3%) respectively. The average yearly
temperature is 17.6 ˚C. July is the hottest month with Mean Monthly temperature
of 22.9 ˚C while January is the coldest month with Mean Monthly temperature
of 9.6 ˚C.
From the climatological balance of Katmandu Valley, it is found that there is
high amount of water surplus (788 mm) compared to water deficit (23 mm).
Therefore soil water demand for dry period could be easily fulfilled by utilizing
about 3% of water surplus. The measured specific discharge of Katmandu valley
is compared with estimated water surplus and the results showed only 4.48%
difference in value. This study will provide the information of climatological
balance and specific discharge of the given area. This information will be useful
for sustainable management of water resources in local and small watershed
environment.