The Sungai Selangor Dam (SSD) and the Sungai Tinggi Dam (STD) are regulating dams located respectively at the riverheads of Sungai Selangor  and Sungai Buloh, a major tributary of Sungai Selangor.

If in the past rain water during the rainy season would  wastefully free-flow to the sea, with the existence of these regulating dams,  the rain water would be collected and stored in their reservoirs. During the dry season, this stored water will  be released into the drying Sungai Selangor to augment the flow of the river, ensuring  sufficient water to meet the demand from the water treatment plants while  helping the river maintain its eco-system.

SPLASH is tasked to  efficiently manage and regulate the water releases from these two dams to  enable sustainable storage and to ensure sufficient quantity of raw water in  the river to meet the water treatment plant demand and other functional needs.