Some water is used to wet the surface of instrument. The rain recorded may be less than the actual rainfall due to the direction of the rainfall as affected by wind. Dents in the collector and tube may also cause error.

There are different types of spillways that can be provided depending on the suitability of site and other parameters. Generally a spillway consists of a control structure, a conveyance channel and a terminal structure, but the former two may be combined in the same for certain types. The more common types are briefly described below: Drop, Ogee, Siphon Chute,

Slight inaccuracies in time keeping by the satellites can cause errors in calculating positions. Satellites drift slightly from their predicted orbits which contributes to errors. Let the GPS receiver receive signals from 4 satellites, then there are two cases: The satellites are at 90° to each other w.r.t the GPS receiver. For demonstration purpose we will take 2 satellites

Stability analysis have been carried out for structures for most severe conditions of horizontal and vertical forces. Stability criteria are aimed at ensuring the overall safety of structure against overturning, flotation and sliding. The structures have been designed so that it should be safe against overturning at any horizontal plane within the structure at the base, or at a plane below

Streams, rivers and lakes are the major sources of surface waters. Usually these sources fulfill the requirements of municipal supplies. Water in these sources originates partly from groundwater outflows and partly from rainwater which flows over the terrestrial areas into the surface water bodies. Outflows from groundwater brings in, the dissolved solids.