It is unlawful for any person to swim within fifty feet of a public boat landing or ramp located on a lake or reservoir constructed or developed by an investor-owned utility for hydroelectric generation. For the purposes of this section, a public boat landing or ramp is one owned or maintained by an investor-owned utility for hydroelectric generation and is available to the public at large. The no swimming area must be clearly marked and signs must be posted to give public notice that no swimming is allowed in the area. Watercraft shall slow to no wake speed when operated within two hundred feet of the landing or ramp. The department shall issue a sufficient number of signs to inform operators of motorboats that the area is a no wake zone. The signs must have printed on them "SLOW TO NO WAKE SPEED". The provisions of this section do not apply in that portion of Game Zone No. 4 in Lancaster County.