35 Pa. Stat. § 2106
Where any dam, breast, ramp, power house or other structure located on any navigable stream or river or on any stream or river declared by law to be a public highway and the pond or reservoir created thereby is used or being prepared to be used by any individual, partnership, association or corporation of or authorized to do business in this State, or by the Commonwealth or any political subdivision thereof for the generation, manufacture, transportation and distribution of electricity or for the storage of water for domestic, industrial or water power purposes, the Water and Power Resources Board of the Department of Forests and Waters, with the approval of the Governor, may at the request of and at the expense of such individual, partnership, association, corporation or political subdivision, or at the expense of the Commonwealth where no private interest is involved, post along each side of the pond or reservoir created by such dam or breast at intervals of not more than three hundred feet of water front from such dam or breast or any ramp and at intervals of not more than three hundred feet of water front on each bank of the river or stream below such dam, breast, ramp, power house or other structure, as the case may be, signs reading "No Entry on These Waters or Property Without Permission: Commonwealth of Pennsylvania, Water and Power Resources Board".
Whoever, without permission of the Water and Power Resources Board, shall wilfully enter or approach upon any dam or breast or on the waters of the pond or reservoir so posted during a period of national emergency or war, shall, on conviction thereof in a summary proceeding, be sentenced to pay a fine not exceeding fifty dollars ($50.00), or to undergo imprisonment not exceeding ten (10) days, or both.
35 P.S. § 2106