Project Name: Songkhla Lagoon Telemetering System
Consultant Company: Asdecon Corporation Co., Ltd. (99.5%)
Partner Company: United Telecom Sales & Services Co.,Ltd. (0.5%)
Scope of work: the responsibilities are installation and set-up of telemetering system, construction of gauging stations, operation and maintenance for telemetering system.
Project Owner: The Royal Irrigation Department (RID)
Project Location: Songkhla Province, Thailand
Project Cost : 34,240,000 Baht
Project Feature: Construction and installation forecasting system
Project Description: Songkhla lagoon is the largest lagoon located in the southern part of Thailand. The Lagoon consist of 3 zones,
1) the lower zone connected to the sea in the gulf of Thailand and strongly influenced by the tide,
2) the middle zone connect with the lower zone with a canal and moderately influenced by the sea water and
3) the upper zone where water in the lagoon is usually fresh for the whole year period. However, in the very dry year, saline water is sometime could protrude this upper zone.
The Royal Irrigation Department (RID) have constructed a pumping station in the upper zone to irrigate an average of 13600 ha rice field. However, the actual planned irrigation area is varied and depend on salinity of the upper zone water.
Every year at the beginning of dry season of cropping, RID officer and farmer would together plan for the appropriate area of farming based on the 3 months forecasted salinity in the upper zone of Lagoon. However, the forecasting is based on the only one or two times grasping of water samplings in the Lagoon and experience of the personal, the accuracy of forecasting is therefore quite uncertainty and are sometime cause the damage to the farmer. It is estimated that on average, the damage due to intrusion for each crop cycle is approximately 300 million bath.
Therefore, to cope with this challenging problem, the long-term forecasting system at specific point and over the Lagoon shall be constructed. One and two dimensional salinity modeling approach were proposed as the innovative tool for water management decision supporting system.
In order to develop the decision support system for forecasting salinity, 9 telemetering stations were installed in Songkhla lagoon for acquiring and monitoring both real-time hydrological and water quality data, all observed data are automatic stored in developed database and forecasting system at master station. The decision support system is developed by using Delft-FEWS program, Delft Hydraulic product, as open and flexible program that allowed to integrate other related models.
There are 4 core computation models operated under Delft-FEWS namely (i) SOBEK as hydrodynamic and salinity model (ii) Harmonic Analysis model for forecasting tidal at mouth of lagoon (iii) Sacramento model as rainfall-runoff model for simulating freshwater discharge from each 8 sub-basins (iiii) WUSMO for estimating irrigation water demand. As the rainfall in the basin is one of the most important factor affecting the salinity in the lagoon and the difficulty in long term rainfall forecasting, the salinity in the Lagoon is forecasted based on 3 scenarios with probability statistical rainfalls of 10 %, 50 % and 90% to cope with dry and flood year.
The decision support system, forecasting system is now under operation at Regional Irrigation office 16, Songkhla province and have recently been used effectively for the crop planning during the dry season of the year 2008.
