No action shall be brought or maintained against any county alone or when acting jointly with any other county under any law, its or their agents, officers or employees, for any noncontractual acts or omissions of such county or counties, its or their agents, officers or employees, relating to the improvement, protection, regulation and control for flood prevention and navigation purposes of any river or its tributaries and the beds, banks and waters thereof: PROVIDED, That nothing contained in this section shall apply to or affect any action now pending or begun prior to the passage of this section.

[1921 c 185 § 1; RRS § 9663. Formerly RCW 87.12.180.]