It shall, be lawful for the Flood Zoning Authority or any of the Officers generally or specially authorized by it in this behalf -
a. to enter upon and survey and take levels of any land within its or his jurisdiction;
b. to mark such levels, boundaries and lines by placing marks or boundary stones;
c. To measure the land;
d. To do all other acts necessary for the purposes of ascertaining the limits referred to in sub-section (2) of section 3; and
e. Where otherwise the survey cannot be completed and the levels taken, to cut down and clear away any part of standing crop, fence or jungle;
Provided that no Flood Zoning Authority or any other Officer shall enter into any building or open any enclosed court or garden attached to a dwelling-house (unless with the consent of the occupier thereof) without previously giving such occupier at least seven days notice in writing of its or his intention to do so.