Groundwater Pollution in the San Fernando Valley – II

Today we continue looking at the decades-old problem of groundwater pollution in the San Fernando Valley. In the previous blog, we looked at how the water got polluted in the first place — we blamed “Rosie the Riveter.” Today, we look at how this problem has migrated from the holes where the wastes were buried into our drinking water wells.
There are two basic hydraulic principles that we need to grasp before we go any further. First, water flows downhill. Simple, yet absolutely important. Second, when we operate a well, the water level in the aquifer around the well drops — we call this the “drawdown.” If we turn this same well off, the water level will return to normal, usually within a few hours — we call this “recovery.”
Wastes are buried below the ground surface (obviously!), but usually above the groundwater level. (If the person doing the burying dug a hole that reached the groundwater level, there would be water in the hole, and they probably would not bury the waste there, and would choose another location instead.) So, the waste starts “uphill.”
The operating wells in the SFV become the low points in the groundwater, due to the drawdown. So where do the wastes go? Downhill! Right into the operating wells.
This doesn’t happen immediately. Water travels very slowly through the ground, typically at just a few feet per day. So it took several years for these wastes to make their way to the operating wells.
The City of Los Angeles (and Burbank and Glendale), being responsible public agencies, shut down the now contaminated wells. Then recovery happened, and the contaminated wells were no longer the low points in the groundwater. These cities still needed water, so they used other wells — existing ones or wells intended to replace the lost production of the contaminated wells. What happened next is really very predictable: drawdown at the newly operated wells shifted the low points in the groundwater. And where did the wastes go? Downhill! So shut those wells down, and shift to others. And the cycle continues.
What we have in the SFV is a game of “Whack-a-Mole” happening on a grand scale. Only instead of the mole popping up out of a hole, the waste “mole” is racing to the lowest “hole” in the groundwater. When we shut down a well, we “whack-a-mole,” but the waste “mole” just moves to the next “hole.”
In a way, the water agencies are acting irresponsibly here: their whack-a-mole game is causing the waste “plume” to migrate much more than it would otherwise. But what options do they have?
It’s high time for someone to step forward and consistently operate a large well or group of wells near the source of the original contamination. This will draw the waste to that operating well field, and allow us to remove it from the aquifer altogether. But that extracted water needs to be treated before it can be used for any purpose. Otherwise, our whack-a-mole game boundaries continue to migrate to wherever we pump this water.
My opinion is that this should be done by the City of Los Angeles, and that the city attorneys should continue to pursue the real responsible parties so that — someday — they can be made to pay for the contamination. But continued inaction only makes the problem worse.

One Response to Groundwater Pollution in the San Fernando Valley – II

  1. avatar mikesac says:

    Interactions between groundwater and surface water are complex. By its very nature, groundwater aquifers are susceptible to contamination from sources that may not directly affect surface water bodies.A spill or ongoing releases of chemical or radionuclide contaminants into soil causes ground water pollution as they seep into the ground.

    Manhattan Air Specialists

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