Once upon a time the Kandy Lake had been designed as a private pool for the King, but since then it had also been used as a destination for wastewater.
Overall, the Kandy Lake is not that big but it offers boat rides and it gives the city some kind of a special center in conjunction with the Dalada Maligawa Temple.
Also the view across the Kandy Lake up on big white Buddha can be amazing depending on the character and intensity of the daylight and that's perhaps why so much romance can be seen around the Kandy Lake.