The canal was able to receive the water that came down and gradually drained it out to the sea,
which is the function of the lagoon as a "monkey cheek".
From the preliminary study of the Royal Initiated Kaem Ling or literally monkey side cheeks (detention) Project that His Majesty the King suggested November 1995 for mitigating flood water, it was deemed appropriate to construct a lagoon or reservoir by utilizing the area near Sanpasamit and Sahakorn canals. Nevertheless, it was found later on that the topography of the area and social impact was not amenable for project implementation, and investment costs were rather high. On 23rd January 1996, H.M. the King visited the reservoir near Queen Suriyothai Royal Monument in Ayudhya province and suggested Mr.Banharn Silpa-archa the Prime Minister and Dr.Sumet Tantivejkul, member and Secretary-General of the Chaipattana Foundation and the officials of the government agencies concerned to carry out a study to solve the flooding problems of the lower part of the Tha-Chin river basin in the form of Detention (Kaem Ling)Project. It will be necessary to construct drainage regulator together with large-scale pumping stations to block off the northern part of the Tha-Chin river from Samut Sakhon upward.
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.