Q. How to observe water level?

Site for installing gauges should be properly selected. The reach should be reasonably straight and of uniform cross· section and slope. The length of such a reach should not be less than 400 m and need not be more than 1600 m. When the length is restricted upstream of the measuring section, it should be double of that on the downstream side. When near a confluence, the site, if on a distributory, should be beyond backwater effect and if on the mainstream, should be beyond the disturbance due to tributary or structures like weirs. The site should be easily accessible even during floods.