California Code, Public Resources Code - PRC § 5093.57

Nothing in this chapter shall be construed to prohibit any measures for flood protection, structural or nonstructural, necessary for the protection of lives and property along the Eel River as described in subdivision (d) of Section 5093.54, except for dams, reservoirs, or other water impoundment structures;  provided, however, that such measures for flood protection may include facilities for temporary flood storage or flood storage basins on tributaries of the Eel River.