Rocky Road to a Fresh Enough Delta

Salinity Intrusion



Rocky Road to a Fresh Enough Delta

Nothing reveals just how much the upper Estuary's seesaw of tides and freshwater flows is micro-managed than prolonged drought, and the resulting fiddling with barriers, gates, and water quality standards to prevent the ocean tides and salinity from intruding too far upstream. Come summer, managers begin to talk fearfully of "losing control of the Delta" and the dreaded outcome: salt water too near the export pumps...
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22
Jan

An emergency barrier installed to protect the state’s water supply from saltwater intrusion during the recent record-setting drought had little effect on the ecosystem.

In spring 2015 the California Department of Water Resources dropped 150,000 tons of rock into False River in the Central Delta to halt encroaching tides that had little freshwater to hold them back. A few months later, it was clear the barrier worked, as salinity rose on one side and fell on the other. But what were the effects on local plants and animals? Through six overlapping yet distinct projects funded by the state Delta Science Program and NASA, and described in the September 2019 issue of San Francisco Estuary and Watershed Science, researchers studied impacts on water quality and movement, zooplankton and phytoplankton, submerged aquatic vegetation, nutrients, and two species of clam. What they found, says Wim Kimmerer of...
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Keeping the Salt Field at Bay II

After four of California’s driest years on record, our “wet” season was so dry that state water officials panicked.Major reservoirs were drawn way down, and record-low snowpack would limit replenishment to a trickle. Water managers worried about the hot, dry months. Would reservoirs still hold enough for freshwater releases to keep saltwater from pushing deep into the Sacramento-San Joaquin Delta? So they built a barrier to block salt instead.
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03
Mar

Keeping the Salt Field at Bay

As the dry, warm days went on and on and on this winter, two guys intimate with California’s Sacramento San Joaquin River delta shifted gears. One reassigned staff from flood to drought response, and the other lay awake at night imagining barriers across various slough openings. By early February, some Sierra reservoirs were so low, and so close to “dead pool” level, that the water projects stopped pumping and delivering. Farmers had to retrench, communities realized they might only have enough drinking water for the next six weeks, and any salmon that succeeded in spawning upstream had no water to carry them down. Things got scary. The water projects asked state regulators to let them off the hook in meeting...
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