(1) Area 1 description. (Columbia River Buffer area.) An area starting at the intersection of the common boundary line between Sections 14 and 15, T6N, R32E and the Washington-Oregon state line; thence north along the section lines ten miles more or less to the southeast corner of Section 22, T8N, R32E; thence east along the section lines two miles to the southeast corner of Section 24, T8N, R32E; thence north along the section lines five miles more or less to the intersection with the Northern Pacific Railroad; thence northeasterly seven miles more or less along the railroad, including the right of way, to the intersection with State Route 124 and C.M. Rice Road at the northeast corner of Section 2, T9N, R33E; thence northerly along C.M. Rice Road, including the right of way, to the Snake River; thence southwesterly along the Snake River to a point near the east section line of Section 23 T9N, R31E; thence south approximately twelve miles to the Walla Walla River; thence west along the Walla Walla River until its intersection with the Columbia River and the Walla Walla-Benton County line; thence southwesterly along the Columbia River approximately three and one-half miles to the intersection of the Washington-Oregon state line; thence east along the Washington-Oregon state line to the point of beginning.

(2) Area 1 restrictions.

(a) The use or application of low volatile ester formulations of use restricted herbicides is prohibited on and after April 5th through October 31st.

(b) On and after April 5th through October 31st, aerial applications of use restricted herbicides are prohibited except by written permit issued by the department.