The supervisors may authorize the construction, extension, enlargement, or acquisition of necessary flood control or stormwater control improvements within the zone or any participating zones. The improvements may include, but shall not be limited to the extension, enlargement, construction, or acquisition of dikes and levees, drain and drainage systems, dams and reservoirs, or other flood control or stormwater control improvements; widening, straightening, or relocating of stream or water courses; and the acquisition, extension, enlargement, or construction of any works necessary for the protection of stream and water courses, channels, harbors, life, and property.