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โครงการหนังสออเล็กทรอนกสด้านการเกษตร เฉลมพระเกียรตพระบาทสมเด็จพระเจ้าอยู่หัว
International Seminar on Biodiversity and Sustainable Development in the Mekong River Basin 41

corresponding to scenario B2). Next is the rice crop. Irrigation water demand of crop rice increases
at least (0.6% in 2050 and 1.9% in 2100, B2 scenario).

Study area
According to the National Center for Planning and Investigation of Water Resources
(NAWAPI), the Central Highlands in general and the SRB in particular are one of the regions most
affected by CC. With the trend of high rainfall in the rainy season and a sharp decrease in the dry
season, it has led to a serious water shortage for the study basin in the dry season. Especially in
recent years, erratic rain has caused a prolonged dry season, high temperature and frequent
droughts in the Srepok River Basin (SRB). Since the SRB is a closed basin, rainwater resources
will play an important role and be the only water source to replenish and supply water for the entire
basin.

Fig 1. DEM and drainage networks of the Srepok River Basin

Under the impact of CC, the tendency of rainfall to increase in the rainy season and
decrease sharply in the dry season has led to a serious water shortage for the basin in the dry
season. Especially in recent years, erratic rain has caused a prolonged dry season, high temperature
and frequent droughts in the SRB. The scenario of rainfall variation in the SRB is located in 4
provinces: Gia Lai, Dak Lak, Dak Nong and Lam Dong. Based on the 2017 version of CC scenario
- Ministry of Natural Resources and Environment built for the above 4 provinces to interpolate the
rainfall change of the SRB according to the above scenarios (NAWAPI). In general, the average
annual rainfall in the 4 Provinces of the SRB increased significantly (NAWAPI). The period 2016
- 2050 compared with the baseline period 1986 - 2005 has the following changes in rainfall: In Gia
Lai, the rainfall increased by 8.3% for the RCP 4.5 average scenario and 10% for the RCP 4.5
scenario. High RCP 8.5. In Dak Lak, the rainfall increases by 6.5 % for the RCP 4.5 scenario and
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