Unless the context clearly requires otherwise, the definitions in this section shall apply throughout RCW 89.08.450 through 89.08.510.

(1) "Watershed restoration plan" means a plan, developed or sponsored by the department of fish and wildlife, the department of ecology, the department of natural resources, the department of transportation, a federally recognized Indian tribe acting within and pursuant to its authority, a city, a county, or a conservation district, that provides a general program and implementation measures or actions for the preservation, restoration, re-creation, or enhancement of the natural resources, character, and ecology of a stream, stream segment, drainage area, or watershed, and for which agency and public review has been conducted pursuant to chapter 43.21C RCW, the state environmental policy act. If the implementation measures or actions would have a probable significant, adverse environmental impact, a detailed statement under RCW 43.21C.031 must be prepared on the plan.

(2) "Watershed restoration project" means a public or private project authorized by the sponsor of a watershed restoration plan that implements the plan or a part of the plan and consists of one or more of the following activities:

(a) A project that involves less than ten miles of streamreach, in which less than twenty-five cubic yards of sand, gravel, or soil is removed, imported, disturbed, or discharged, and in which no existing vegetation is removed except as minimally necessary to facilitate additional plantings;

(b) A project for the restoration of an eroded or unstable stream bank that employs the principles of bioengineering, including limited use of rock as a stabilization only at the toe of the bank, and with primary emphasis on using native vegetation to control the erosive forces of flowing water; or

(c) A project primarily designed to improve fish and wildlife habitat, remove or reduce impediments to migration of fish, or enhance the fishery resource available for use by all of the citizens of the state, provided that any structure other than a bridge or culvert or instream habitat enhancement structure associated with the project is less than two hundred square feet in floor area and is located above the ordinary high water mark of the stream.