Worry and suspicion reign as once-dry Tulare Lake drowns California farmland

[Zorro]

Sixth Avenue used to cut through miles of farmland. Now, the road has disappeared under muddy water, its path marked by sodden telephone poles that protrude from the swelling lake. Water laps just below the windows of a lone farmhouse that sits alongside the submerged route.

Thousands of acres of cropland have been inundated in this heavily farmed swath of the San Joaquin Valley. And the water just keeps rising.

For the first time in decades, Tulare Lake is reappearing in the valley, reclaiming the lowlands at its historic heart. Once the largest freshwater lake west of the Mississippi River, Tulare Lake was largely drained in the late 19th and early 20th centuries, as the rivers that fed it were dammed and diverted for agriculture.

This month, after a historic series of powerful storms, the phantom lake has reemerged. Rivers that dwindled during the drought are swollen with runoff from heavy rains and snow, and are flowing full from the Sierra Nevada into the valley, spilling from canals and broken levees into fields that usually teem with lucrative plantings of tomatoes, cotton and hay.

https://www.latimes.com/environment/story/2023-03-24/as-tulare-lake-reappears-floodwaters-raise-tensions-in-san-joaquin-valley

Who could have thought farming on a dry lakebed might have some issues?

[dem4decades]

1. I've seen reports of deleted aquifers, like ridiculously depleted. Well any

Of this rain recharge them or is it all runoff and surface capture?

[efhmc]

2. Yes.

"During the hydrologic cycle, replenishment occurs naturally when rain, storm water and the flow from rivers, streams and creeks seeps into an aquifer. Water also gets into the ground as farmers irrigate fields and orchards."

[dem4decades]

3. I get that but some of these aquifers are down almost 100 feet, does that ever get recharged?

[efhmc]

4. More from google.

"The rainfall that seeps into the ground on your property moves through the soil at a rate of only 10 feet per year. Since aquifers (where your well gets its water supply) are hundreds of feet below ground, it might take more than a decade for that rain to reach an aquifer or water-bearing strata! But that’s a good thing – as it slowly moves through the soil, the water chemistry changes and the water is purified of most surface contaminants.

So is rainfall still an important factor in your well? YES! Rainfall has a direct impact on the local water table, which may immediately impact your residential well if it is supplied by shallow aquifers. With less rain, or changes in aquifer structure, the well becomes non-water bearing – i.e. dry. Your well may not ‘fill up’ when it rains, but it does reap the indirect benefits."

[2naSalit]

5. The governor has mandated...

Governor Newsom Issues Executive Order to Use Floodwater to Recharge and Store Groundwater

Published: Mar 10, 2023

WHAT TO KNOW: As storms bring rain and snow to California, Governor Newsom signed an executive order that makes it easier to capture floodwater to recharge groundwater – temporarily lifting regulations and setting clear conditions for diverting flood stage water without permits to boost groundwater recharge storage.
SACRAMENTO – Governor Gavin Newsom signed an executive order to enable local water agencies and other water users to capture water from the latest round of storms to recharge state groundwater supplies.

The order suspends regulations and restrictions on permitting and use to enable water agencies and water users to divert flood stage water for the purpose of boosting groundwater recharge. The order includes wildlife and habitat protections, ensuring that any diversions would not harm water quality or habitat or take away from environmental needs.WHAT GOV. NEWSOM SAID: “California is seeing extreme rain and snow, so we’re making it simple to redirect water to recharge groundwater basins. This order helps us take advantage of expected intense storms and increases state support for local stormwater capture efforts.”

https://www.gov.ca.gov/2023/03/10/governor-newsom-issues-executive-order-to-use-floodwater-to-recharge-and-store-groundwater/

The EO: https://www.gov.ca.gov/wp-content/uploads/2023/03/3.10.23-Ground-Water-Recharge.pdf?emrc=641e14ca3b61a

[hatrack]

6. There's also a compression problem, meaning parts of the aquifer can no longer recharge

EDIT

Fine-grained sediments (clays and silts) within an aquifer system are the main culprits in land subsidence due to groundwater pumping. Fine-grained sediments are special because they are composed of platy grains (imagine the shape of dinner plates). When fine-grained sediments are originally deposited, they tend to be deposited in random orientations (imagine haphazardly placing your dinner plates in the sink). These randomly oriented sediment grains have a lot of room between them to store water. However, when groundwater levels decline to historically low levels, those randomly oriented sediments are rearranged into stacks (imagine plates stacked in the cupboard). These stacks occupy less space and also have less space between them to store water.

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The effects of compaction fall into two categories: those on manmade infrastructures and those on natural systems. The greatest effects occur to infrastructures that traverse a subsiding area. In the San Joaquin Valley, the main problems reported are related to water conveyance structures. Many water conveyance structures, including long stretches of the California Aqueduct, are gravity driven through the use of very small gradients; even minor changes in these gradients can cause reductions in designed flow capacity. Managers of the canals, such as the California Department of Water Resources, the San Luis Delta-Mendota Authority, the Bureau of Reclamation, and the Central California Irrigation District, have to repeatedly retrofit their canals to keep the water flowing...albeit at reduced amounts. While water conveyance structures tend to be the most sensitive to subsidence, damage to roads, railways, bridges, pipelines, buildings, and wells also can occur.

While more focus has been placed on the highly visible infrastructure damage from subsidence, which generally can be repaired, compaction of the aquifer system, sight unseen, may permanently decrease its capacity to store water; subsidence occurring today is a legacy for all tomorrows. Even if water levels rose, compacted sediments would remain as-is; most compaction that occurs as a result of historically low groundwater levels is irreversible. Additionally, as the topography of the land changes by varying amounts in different places, the low areas, such as wetlands, will change size and shape, migrate to lower elevations, or even disappear. Rivers may change course or erosion/deposition patterns to reach a new equilibrium.

EDIT

https://www.usgs.gov/centers/land-subsidence-in-california/science/aquifer-compaction-due-groundwater-pumping