Application of SWAT Model to assess the climate change impact on water balance over the cereal crops in the West Seti River Basin
Vol. 15,
EGU2013-7933-2, 2013
EGU General Assembly
2013
© Author(s)
2013. CC Attribution 3.0 License.
Pabitra Gurung (1), Luna Bharati (1), and Saroj Karki (2)
(1) International Water Management Institute (IWMI), Kathmandu, Nepal
(p.gurung@cgiar.org),
(2) Institute of Engineering, Pulchowk Campus, Tribhuvan
University, Kathmandu, Nepal
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The West Seti River basin located in the far western region of
Nepal has catchment area of 7,438 km2 and annual rainfall is about 1921 mm. According to report
on climate change and vulnerability mapping in watersheds in middle and high
mountain regions (Siddiqui et al., 2012), this basin is one of the most
vulnerable river basin of Nepal. The average elevation of the basin is 2505 m
but it varies from 314 m at basin outlet to 7043 m of Api and Nampa high
mountain ranges. Agricultural land in the basin is categorized in three types;
cultivation in level terraces, cultivation in slope terraces and cultivation in
valley. Based on the landuse classes basin has approximately 377 km2
area of level terraces, 227 km2 area
of slope terraces and 67 km2 area
of valley cultivation. In the basin, major
summer cereal crops are rice, maize and millet; and major winter cereal crops
are wheat and barley. The Soil and Water
Assessment Tool (SWAT) is used to simulate the water balances in the different
cropping pattern under current and future
climatic condition. The result shows that total precipitation over the rice,
maize, millet, wheat and barley field are 1002
mm, 818 mm, 788mm, 186 mm and 169 mm respectively whereas total simulated actual evapotranspiration (ET) are 534 mm, 452
mm, 322 mm, 138 mm and 177 mm respectively under current climate. In similar cropping pattern, actual ET will change by
+0.7% in rice, +3.4% in maize, -3.4% in millet,
+41.2% in wheat and +36.2% in barley under future climate projection. Result of
cropping yield shows that rice, maize and
millet yield will decrease by 10%, 7.9% and 26.1% whereas yield of wheat and
barley will increase by 7.8% and 5.8%
accordingly. Therefore, climate change result shows that yield of summer crops
are in decreasing trend and winter crops are
in increasing trend.
Key
Words: Water Balance, Hydrological Modeling, Climate Change, Crop Yield, SWAT
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Abstract selected for the European Geosciences Union General Assembly, April, 2013.
Vienna, Austria
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