s time , Houay Por HPP is to be developed by means of trans-basin, it is to build a dam near Ban Senvang on Xe Set River ( referred to as the main dam site), and it is to build a low dam on Houay Por River through the channel to Houay Por River for power generation. Measuring from 1:50,000 topographic map of Lao PDR, the water catchment area U/S of the main dam site of Houay Por HPP is 436km2, the river length is 66.6km, and the gradient is 17%, while the water catchment area U/S of the saddle dam site is 4.2km 2, the river length is 5.2km, and the gradient is 19%.