During the flooding season, these flood gates will allow the excess water to drain into the Gulf of Thailand. But during the high tides, these flood gates will prevent the sea water from inundating the land. During the flooding season, it is also possible and desirable to pump the flood water into the river, or to rechannel the flood water to the left or right sides into the Gulf or Thailand. Such an operation will enable the Tha-Chin river on the northern side of the flood gates to serve as "Kaem Ling" or "detention" which can detain the flood water and eventually drain the water into the Gulf of Thailand in an efficient manner.
The Detention Project of the lower part of the Tha-Chin river is a large-scale project which requires a proper feasibility study, and which takes account of possible impacts. The implementation period is five years which has already been included in the plan to solve flooding problems of Bangkok and surrounding provinces.
Subsequently on 5th, 9th, 12th and 24th of February 1996 at Dusit Throne Hall of the Grand Palace, His Majesty the King further suggested to Prime Minister Banharn Silpa-archa, Dr.Sumet Tantivejkul (Secretary-General of the Chaipattana Foundation), and officials from other concerned agencies to speed up the study and consider the implementation of the Detention Project at Mahachai-Sanamchai canals and other connecting canals. This is because the area surrounding Mahachai-Sanamchai canals is the low land into which the water drains and is near to the flooded area covering Samut Sakhon, Nakhon Pathom and Bangkok provinces. The project may entail construction of flood gates to block off all the canals together with installation of water pumps. Such project should not require high investment cost and should be well worth the investment. Furthermore, it can also be networked with the "Detention Project" of the lower part of the Tha-Chin river. Together, they should represent a system to relieve flood problems of Bangkok and surrounding provinces in an efficient manner.
For the implementation of this project, the Royal Irrigation Department will carry out a study and analyze details concerning buildings and other construction work which should be consistent with the physical environment, land use, hydrological conditions of all the canals and other social and environmental factors. The design will be completed within budgetary year 1997 and construction of flood gates for water drainage of Mahachai canal and pumping stations may start thereafter.