(a) Name. The name of the viticultural area described in this section is “Lamorinda”. For purposes of part 4 of this chapter, “Lamorinda” is a term of viticultural significance.

(b) Approved maps. The four United States Geological Survey (USGS) 1:24,000 scale topographic maps used to determine the boundary of the Lamorinda viticultural area are titled:

(1) Walnut Creek, CA, 1995;

(2) Las Trampas Ridge, CA, 1995;

(3) Oakland East, CA, 1997; and

(4) Briones Valley, CA, 1995.

(c) Boundary. The Lamorinda viticultural area is located in Contra Costa County, California. The boundary of the Lamorinda viticultural area is as described below:

(1) The beginning point is on Walnut Creek map at the water tank (known locally as the Withers Reservoir) at the end of an unnamed light-duty road known locally as Kim Road, in the Cañada del Hambre y Las Bolsas Land Grant.

(2) From the beginning point, proceed south-southeast in a straight line approximately 0.8 mile to the 833-foot peak marked “Hump 2;” then

(3) Proceed southeast in a straight line approximately 1.7 miles to the marked 781-foot peak south of the shared Lafayette-Walnut Creek corporate boundary line and north of an unnamed light-duty road known locally as Peaceful Lane; then

(4) Proceed southeast in a straight line approximately 0.3 mile to the marked 610-foot peak southwest of an unnamed light-duty road known locally as Secluded Place; then

(5) Proceed south-southwest in a straight line approximately 1.7 miles to an unidentified benchmark at the end of an unnamed unimproved road known locally as Diablo Oaks Way in section 33, T1N/R2W; then

(6) Proceed southeast in a straight line approximately 0.5 mile, crossing onto the Las Trampas map, and continuing another 0.9 mile to the substation at the southeast corner of section 4, T1S/R2W; then

(7) Proceed southeast in a straight line approximately 2.3 miles to the 1,827-foot summit of Las Trampas Peak, section 22, T1S/R2W; then

(8) Proceed south-southeast in a straight line approximately 2.1 miles to the 2,024-foot benchmark marked “Rock 2” in section 26, T1S/R2W; then

(9) Proceed west-southwest in a straight line approximately 2.7 miles to the marked 1,057-foot peak in section 29, T1S/R2W; then

(10) Proceed west-southwest in a straight line approximately 2 miles to the intersection of the 1,000-foot elevation line with the Contra Costa-Alameda County line in section 31, T1S/R2W; then

(11) Proceed northwest in a straight line approximately 0.4 mile, crossing onto the Oakland East map, then continuing another 0.1 mile to the 1,121-foot peak in section 30, T1S/R2W; then

(12) Proceed northwest in a straight line approximately 3.6 miles to the 1,301-foot peak in section 15, T1S/R3W; then

(13) Proceed northwest in a straight line approximately 1.6 miles to the 1,634-foot peak in section 9, T1S/R3W; then

(14) Proceed northwest in a straight line approximately 2.2 miles to the communication tower on the Contra Costa-Alameda County line in section 5, T1S/R3W; then

(15) Proceed north in a straight line approximately 0.1 mile, crossing onto the Briones Valley map, then continuing another 0.6 mile to the 1,905-foot summit of Vollmer Peak in the El Sobrante Land Grant; then

(16) Proceed north-northeast in a straight line approximately 3 miles, crossing over to the 1,027-foot peak in the Boca de la Cañada del Pinole Land Grant, to the Orinda corporate boundary line; then

(17) Proceed generally east along the Orinda corporate boundary line approximately 3.3 miles to the water tank at the 1,142-foot elevation in the Boca de la Cañada del Pinole Land Grant; then

(18) Proceed east-northeast in a straight line approximately 1.2 miles to the 1,357-foot benchmark marked “Russell” in the Boca de la Cañada del Pinole Land Grant; then

(19) Proceed northwest in a straight line approximately 0.8 mile to the 1,405-foot peak in the Boca de la Cañada del Pinole Land Grant; then

(20) Proceed east-northeast in a straight line approximately 0.5 mile, crossing onto the Walnut Creek map, then continuing another 1.1 miles to the beginning point.