TITLE
Recommendation to receive and file report, “Elevation Changes in the City of Long Beach, November 2014 through April 2015.” (Citywide)
DISCUSSION
The City of Long Beach, through the Long Beach Gas and Oil Department (LBGO), supervises oil production and subsidence control operations in the Wilmington Oil Field. LBGO conducts elevation surveys every six months to monitor elevation changes in the oil fields and adjacent city areas. This report focuses on elevation changes that have occurred from November 2014 through April 2015. The LBGO survey includes the following areas: Civic Center, Central City, Alamitos Bay, Naples, Harbor District, and the offshore area encompassing the four oil islands.
The results of the six-month survey show that elevations were stable in the Civic Center, Central City, Alamitos Bay, and Naples. The offshore area was stable except for a small area adjacent to Island Grissom which experienced a decline of 0.06 foot (0.7 inch). The decline is within normal limits and not expected to continue. The Harbor District was stable during the six-month period.
The LBGO survey uses a series of benchmarks to determine elevation changes. Studies by the Department’s engineers and geologists show that the benchmarks may rise and fall in such a manner as to make a survey either optimistic (slightly up in elevation) or pessimistic (slightly down in elevation). These changes in elevations may be associated with tidal cycles, temperature changes, and/or deep earth tectonic changes or re-pressuring operations. Surface elevations over the active Wilmington Oil Field can be expected to fluctuate under changing water flood conditions.
This matter was reviewed by Deputy City Attorney Richard Anthony and by Budget Operations Officer Grace Yoon on July 15, 2015.
TIMING CONSIDERATIONS
City Council action on this matter is not time critical.
FISCAL IMPACT
There is no fiscal impact or local job impact associated with this action.
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