Let me tell you what I know. Little knowledge is a dangerous thing, however. Susta is a vdc in Nepal bordering India in the edge of the Narayani river in Nawalparashi district. I have been there once to take a holy deep in Triveni when I was a Kid and nearly drowned! India has constructed a barrage just in the broder. It's called Gandak Barrage. It was constructed in the early 1960's probably during the BP Koirala government. Mahendra was the KIng for sure. BP and the Nepali congress govt. is blamed for 'selling Gandaki ' for this reason. So there is a barrage just in the border which regulates the flow of Narayani river as soon as it enters the Indian territory. Besides the river itself , In the south of the barrage, a channel(nahar) that irrigates the sitamadhi district of BIhar is built and subsequently in the north there is another nahar built in Nepals territory. this as a gesture of Indian goodwill to Nepal. So when monsoon comes Indian irrigation people block the flow of Narayani river in its course and limit the level of water going through the southern channel towards Bihar. In the mean time they open up the channel through Nepal to flush the flodded water which result in heavy flooding in the villages around the nahar.Every monsoon, the locals are hit by severe flooding. This should be the susta prakanran. And the Nepalese are complaining that Indians are encroaching Nepal's territory by building the border check point and moving them further north year by year. as far as I know.