Sukanlaya Trewitthayanuruk. Application of a mathematical model for water balance studies of Petchaburi sub-watershed . Master's Degree(Technology of Environmental Management). Mahidol University. : Mahidol University, 2003.
Application of a mathematical model for water balance studies of Petchaburi sub-watershed
Abstract:
The objectives of this thesis were to study the physical characteristics,
hydrometeorology, water mass balance and water resource management in Petchaburi
sub-watershed area. Petchaburi sub-watershed area is a part of Petchaburi watershed
area, which Petchaburi river is the main river and, Huai Phak and Huai Mae Prachan
creeks are the branches. There is one large water source development project, Kaeng
Krachan reservoir.
This study used various water management programs. MIKE BASIN combination
with ArcView GIS program was used to construct a mathematical model to examine the
potential of the water resource, water requirements and water balance of this watershed.
The model was adjusted in four topics, 1) the development condition of the watershed:
current year, short-term future, medium-term future and long-term future, 2) the
potential of the Petchaburi irrigation project, 3) the Rule Curve consideration or nonconsideration
of the Kaeng Krachan reservoir, and 4) the development of the Huai Phak
and Huai Mae Prachan reservoirs in the future, 36 watershed condition models were
constructed. The other programs were used to construct the time series of the rainfall,
runoff and water requirement in various activities.
The result revealed that the watershed condition model in the current year and the
short-term future had the similar trend of water resource management. The irrigation
efficiency of the Petchaburi irrigation project during the wet to dry seasons was 35-45 %
and considered the Rule Curve of Kaeng Krachan reservoir. Petchaburi sub-watershed
had the total water available of 1,992 MCM/year, water requirement of 1,347
MCM/year and non-water requirement of 1,005 MCM/year. From the data of past 30
years, the model predicted water shortages in 10 years in the lower Petchaburi subwatershed,
15 years in Huai Phak sub-watershed and 6 years in Huai Mae Prachan subwatershed.
The medium-term future of the watershed model had 35-45% of the
irrigation efficiency during the wet to dry seasons and considered the Rule Curve. The
model predicted that there would be water shortages in 8 years in Huai Mae Prachan
reservoir and 1-4 years in the upper and lower Huai Mae Prachan sub-watershed,
respectively. The model of the watershed development condition in the long-term future
showed irrigation efficiency of 40-50% and considered the Rule Curve. The model
predicted that water shortages would occur in 8-10 years in the lower Petchaburi subwatershed
and 11-12 years in the upper and lower Huai Phak sub-watershed,
respectively. However, there would not be water shortages in Huai Phak reservoir.