Study of Water Budget for the Yom River in Sukhothai-Phitsanulok Floodplain
Sombat Chuenchooklin (1)
(1) Department of Civil Engineering, Faculty of Engineering, Naresuan University
In this research which was sponsored by our faculty-fund since year
1999. The simple water balance model was chosen for calculating the
storage of water in such model. By using local hydro-meteorological data
include rainfall and stream-flow data to be analyzed according to the
statistics for hydrological analysis. The natural storage such as
streams, swamps and wet areas also were collected together with land-use
in this studied area, which is large flood and losses. The analysis of
evapotranspiration, crop water requirement, consuming use, and surface
storage were carried out. The studied area is 1,601.81 km2. It is
located in Sukhothai-Bangrakam floodplain, which the altitude is ranged
between +36.00 to +54.00 m(msl). There is the Yom river flow via the
middle of the area and there are many inundation canals connect to both
banks of the Yom. The amount of storage was 5.94 km2 and 253.73 km2 for
streams and wet area, respectively. The reference evapotranspiration was
calculated by Penman-Monteith method with amount of 1,520.33 mm/yr.,
while annual rainfall was 1,147.7 mm. Flood analysis from various
gagging stations compare to Kaengluang (Y6) result fair to good with
0.767-0.976. Flood reducing was great amount between the reach of
Srisamrong (Y33) to Sukhothai (Y4) while the excess flood was increased
more in the end of the studied area in Bangrakam (Y16). Due to the
reduction of shape of the Yom, it is could not carry of existing flood
and it will be flooded over the area in both banks of the river and go
to natural storage areas in 259.7 km2. The crop water requirement was
calculated by CROPWAT (FAO) by using crop data in 1995-1997 with 1.19 of
crop intensity. The total amount of crop water needs 472.88 million
cubic meters annually plus some water for consuming, evaporating and
deep percolating is totally 530.21 million cubic meters per year. From
the water balance, total flood amount about 600-700 million cubic meters
had flown to the lowest area in 255.3 km2 and in natural streams and
ponds 67.8 km2 with the mean depth was 2.57 m. The other reason for the
reduction of flood is clearly seen from the recharging water to
groundwater. It is the evident of using many tube-well pumps in the
studied area with total 331 number of wells and 204 deep wells neighbor
of the bound. This reason shown by the using water budget principle that
if the water table is not declined, so that the amount of water recharge
will be assumed to be equal to flood reduction.
Submittal Information
Name :
Date :
Dr. Sombat Chuenchooklin
07-May-01-09:27:36
Organization :
Theme :
Department of Civil Engineering, Faculty of Engineering, Naresuan University
