Section 251 in Rajasthan Land Revenue (Land Records) Rules, 1957
251. Locality of Rain-guage.
- (i) It has been found that a rain-gauge exposed on a perfectly open space registers less than the true amount of rain. This arises because the wind forms an eddy over the mouth of the gauge and carries away small drops which would otherwise have entered the gauge. Accordingly a certain amount of protection from the wind is advantageous, at the same time no obstacle should be so near to the gauge as actually to shield it from rain which may be falling at a considerable angle.(ii)The following rule has been found to be most satisfactory in practice.(a)The distance between the gauge and the nearest object should be at least twice the height of that object.(b)If this rule is followed the presence of trees and bushes in the neighbourhood of a gauge is rather to be encouraged than otherwise. But as trees may be allowed to grow without being effectively lopped, no tree should be planted within thirty yards of the gauge.(c)The gauge should never be situated on the side or top of a hill if a suitable site on level ground can be found. In the hills, where it is difficult to find a space, the site for the gauge should be chosen where it is best shielded from high winds, and where the wind does not cause eddies.(d)Only under very exceptional circumstances should a gauge be exposed on a roof. It is not intended that all the gauges, now on roofs, should be at once removed to ground sites. Opportunities should, however, be taken as they arise for effecting a change, for example, when an office is removed from one building to another, or when a site on a roof becomes unsuitable.
