One of His Majesty's most innovative flood prevention projects is called Kaem Ling which means Monkey Cheek Project. In 1995, he explained that his inspiration for the project originated from his childhood memory of monkeys: "I remember that when I was five years old, we had monkeys and we gave them bananas. They would munch.[on the bananas] and then keep the food in their cheeks." His Majesty applied this concept to the storage of water for use in times of need by constructing ".a retention area to keep back water when the sea water surges up and we cannot evacuate the floodwater." we must [therefore] have a 'Monkey Cheek' and let the water out whenever it is possible.

The project was first undertaken in Thonburi. Watergates were constructed and high-powered pumps were installed; polders were built across streets with lanes leading to the river's edge. Today, when heavy rainfall threatens to flood the streets the Kaem Ling Project helps move the excess water into the Chao Phraya River so the city remains dry.

The success of the project spawned similar efforts in other areas such as Rangsit, Saraburi, Ayutthaya, Pathum Thani, and Samut Prakan. Similar watergates were installed along the rims of other rivers, like the Tha Chin River, which drains the floodwater from the Central Plains into the Gulf of Thailand.