Question: In what county is the university at which Walter Oechel teaches located?

Context paragraphs:
Walter Johnson (historian): Walter Johnson (b. in Columbia, Missouri) is an American historian, who teaches history and directs the Charles Warren Center at Harvard University.

Walter Scheidel: Walter Scheidel (born 9 July 1966) is an Austrian historian who teaches ancient history at Stanford University, California.  Scheidel's main research interests are ancient social and economic history, pre-modern historical demography, and comparative and transdisciplinary approaches to world history.

Walter C. Oechel: Walter C. Oechel works in the areas of plant eco-physiology, systems ecology, global change, and biosphere-atmosphere interaction.  At the San Diego State University he is as a Distinguished Professor of Biology, as well as at the Open University, UK.  He is also co-director of the Center for Climate and Sustainability Studies (C2S2) and the director of the Global Change Research Group at SDSU.

Walter van Laack: Walter van Laack (born 1957 in Cologne ) is a German specialist in orthopedics, Special Orthopaedic Surgery and Sports Medicine.  He lay at the University of Cologne from his state examination and attained a doctorate 1982 at the RWTH Aachen University.  Van Laack practiced in an orthopedic group practice in Herzogenrath and teaches at the Fachhochschule Aachen the subjects medical, orthopedic and border areas of medicine.  2014 he was appointed professor here.  He is also managing director and co-owner of his own book publishing company.

Walter Everett (musicologist): Walter Everett is a music theorist specializing in popular music who teaches at the University of Michigan.

Walter Bortz II: Walter Michael Bortz II, (born March 20, 1930) is an American physician and author who teaches medicine at Stanford University.  He is one of America's leading scientific experts on aging, and promotes the possibility of a 100-year lifespan.

Walter Kofler: Walter Kofler (born May 27, 1945, Tyrol, Austria) is an Austrian physician and philosopher of medicine.  Until 2010 he was professor at the Innsbruck Medical University and teaches since 2012 at the I.M. Sechenov First Moscow State Medical University.  He is President of the International Academy of Science, Munich.

Mary Mackenzie (mezzo-soprano): Mary MacKenzie is an American classical mezzo-soprano and voice teacher.  She earned both bachelor and master of music degrees from the Juilliard School.  In 1955, she won the Walter W. Naumburg Foundation competition, and in 1960, she won the Metropolitan Opera National Council Auditions.  She was also twice awarded the Martha Baird Rockefeller Fund grant and was a recipient of the Sullivan Award.  Her performance credits include appearances with The Bach Choir of Bethlehem, the Dallas Opera, the Lyric Opera of Chicago, the Metropolitan Opera, the NBC Opera Theatre, the New Orleans Opera, the San Diego Opera, and the Santa Fe Opera among others.  She was formerly the head of the vocal pedagogy department at San Diego State University where she taught for more than 20 years.  She currently teaches private voice lessons at Point Loma Nazarene University and is the administrative vice-President of the Board of the National Association of Teachers of Singing (NATS).  She previously served as the Vice-President of NATS for five years.

Florence Marina State Park: Florence Marina State Park is a 173 acre Georgia state park located near Omaha on the eastern shore of Walter F. George Lake.  The park is known for its deep-water marina and its water recreation sports, such as fishing and waterskiing.  The park also attracts bird-watchers with the chance of seeing herons, egrets and, possibly, bald eagles.  The park is home to the Kirbo Interpretive Center, which teaches visitors about Native Americans and displays snakes, turtles, fish, and other artifacts from prehistoric times to the early 20th century.  Located just southeast of the park is Providence Canyon State Outdoor Recreation Area.

San Diego State University: San Diego State University (SDSU, San Diego State) is a public research university in San Diego, California, and is the largest and oldest higher education institution in San Diego County.  Founded in 1897 as San Diego Normal School, it is the third-oldest university in the 23-member California State University (CSU).  SDSU has a Fall 2016 student body of 34,688 and an alumni base of more than 280,000.

Supporting paragraphs: Walter C. Oechel San Diego State University
Answer: San Diego County