I see....

Canie had mentioned that a water purification plant in the LB area conducts water injection (to keep the sub-surface water fresh by keeping seawater out ??)

Maybe the pond's level rising by that much is an effect of water injection being used to fill aquifers (with excess rain run-off). In this case, the "water injection" part would suggest an increase in seismicity in the region.

Looking at the linked map...it appears that things have perked up a tad. So you may very well be on to something (using the pond level as an indicator of aquifer saturation levels and {inferred} water injection going on in the area).

Perhaps you could stick a marked yardstick ruler in the pond to enhance the measurments of change? Just an idea....

• quake map - LA /LB area