No action, claim, or other proceeding for compensation for damage occasioned by the construction or maintenance of works under this Act shall be maintainable unless:
(a) notice in writing stating the nature and extent of the damage complained of has been furnished to the constructing authority within six months after the damage in respect of which the notice is given has been occasioned, and
(b) after giving the notice the person claiming compensation proceeds without unreasonable delay to obtain such compensation.