TITLE
Recommendation to receive and file the report, “Elevation Changes in the City of Long Beach, November 2020 through November 2021.” (Citywide)
DISCUSSION
The City of Long Beach (City), through the Energy Resources Department (Energy Resources), supervises oil production and subsidence control operations in the Wilmington Oil Field. Energy Resources 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 2020 through November 2021. The Energy Resources 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 last two six-month surveys indicate that elevations were stable in the Civic Center, Central City, Naples, the offshore islands, and the City north of Wilmington Oil Field. During the first six-month period, the Alamitos Beach shoreline experienced a rise in elevation of up to 0.06 foot (0.7 inch), a trend that reversed during the second half of the year, possibly due to temporary changes in fluid injection volume. The decline is not expected to continue. The central portion of the Harbor District experienced an annual rise in elevation of as much as 0.08 foot (1 inch). The northwest corner of the Harbor District experienced an annual decline in elevation of as much as 0.07 foot (0.8 inch). The elevation changes are minor, and fluid injection and production will be closely monitored and adjusted to mitigate future changes. Finally, elevation changes of up 0.1 foot (1.2 inches) were observed outside of the Wilmington Oil Field operated areas, specifically near the Recreation Park District, Marine Stadium and the Colorado Lagoon. The changes are considered minor and are possibly due to normal tectonic movement along the active Palos Verdes and Newport-Inglewood fault zones.
The Energy Resources survey uses a series of benchmarks to determine elevation changes. Studies by Energy Resource’s engineers and geologists show 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, drought, temperature changes, deep earth tectonic changes, dewatering activities, and/or re-pressuring operations in the oil field. Surface elevations over the active Wilmington Oil Field can be expected to fluctuate under changing waterflood conditions.
This matter was reviewed by Deputy City Attorney Richard F. Anthony on February 22, 2022 and by Revenue Management Officer Geraldine Alejo on March 3, 2022.
TIMING CONSIDERATIONS
[Timing Considerations]
FISCAL IMPACT
This recommendation has no staffing impact beyond the budgeted scope of duties and is consistent with existing City Council priorities. There is no fiscal or local job impact associated with this recommendation.
SUGGESTED ACTION
Approve recommendation.
Respectfully Submitted,
ROBERT M. DOWELL
DIRECTOR OF ENERGY RESOURCES
APPROVED:
THOMAS B. MODICA
CITY MANAGER