Changla, at about 15000ft above MSL. This is a reservoir built to check the flow of water from the glaciers. Norphel’s simple technique checks the flow of water by using diversion canals at heights of 12000-15000 ft. He builds simple bunds using stones and very little mortar. They are held together by an iron mesh. Water thus collected in the reservoir is let down slowly through narrow outlets. Reduction in the speed of the flow helps to refreeze it.