Abstract:Abstract:To make a better choice about the energy dissipation forms for the arch dam downstream

the hydraulics indicators of three forms were compared in this paper. The test results showed that under the scheme of the long apron

the flow regime was poor

the baseplate and revetment was unstable; that under the scheme of the water cushion pond and second dams

the flow regime and hydraulics indexes met the requirements

however

the hydraulic optimization of water cushion pond was complex and the cost ofsecond dam was high; that under the scheme of the short apron

the position and depth of scouring pit were within the scope of the permit

but it could harm the security and stability of the arch dam for the geological conditions of factors. Based on the test results

the scope of the short apron can be determined preliminarily. Thus

combined with the test results

engineering experience

geological conditions and project cost，the first choice for scheme of downstream energy dissipation was short apron scheme.