Episode 1: “Unraveling the Knot” Water movement in the Sacramento-San Joaquin Delta

By Bill Fleenor, Amber Manfree, and Megan Nguyen

In 2010, John DeGeorge of RMA, Inc used animated model results to illustrate specific flow and water quality issues in the Delta to the State Water Board. The Center for Watershed Sciences, working with John and using RMA software, has assembled a series of narrated animations to show some major forces acting on Delta flows and water quality. The goal is to “Unravel the Knot” of California’s Delta – at least some it – in terms of flow and water quality.

In Episode 1 we start with general background of California water and the role and significance of the Delta.

The main points are:

  • The Sacramento-San Joaquin Delta watershed covers 40% of California and most of the water used in the state by humans. Rain and snowmelt feed rivers, supporting a wide variety of habitats and large populations of wildlife.
  • The Delta is a critical hub in California’s water infrastructure, conveying fresh water from the wetter northern part of the state to farms and cities in the drier south. Water deliveries supporting intensive agriculture and supplying urban areas have spurred enormous economic growth. This has come with significant environmental tradeoffs.
  • The Delta is largely tidally influenced, and potential for rapid large-scale flooding of sunken island interiors, combined with sea level rise impacts, threaten its use as a conduit for water delivery, and raise the possibility of sudden, sweeping environmental changes.
  • Understanding how water moves in the Delta can help in planning for the future. This video series examines each component of water movement separately, and explains how shifts in water management, levee failure, and sea level rise might change the Delta and California’s water supply in the years ahead.

William Fleenor is a senior researcher who specializes in hydrodynamics and hydraulic modeling at the UC Davis Center for Watershed Sciences. Amber Manfree is a postdoctoral researcher with the UC Davis Center for Watershed Sciences. Megan Nguyen is a GIS researcher at the Center for Watershed Sciences.

Further Reading

A Tale of Two Deltas: A Comparison of Transport Processes in the Predevelopment and Contemporary Delta (Jon Burau, as summarized by Maven, 2016)

Episode 1: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Introduction

Episode 2: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Tidal Forces

Episode 3: “Unraveling the Knot” – Water movement in the Sacramento-San Joaquin Delta – Managing Flows

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9 Responses to Episode 1: “Unraveling the Knot” Water movement in the Sacramento-San Joaquin Delta

  1. What an AWESOME project. The topic of bay area water flows has fascinated us a simplewater.us for a long time. It can be very very complicated to understand, not to mention explaining these matters to other people. I’m so glad you’re doing this! Let us know if you need / want bay area water quality data !!!

  2. Gayle Garman says:

    Episode 1 of “Unraveling the Knot” is a short, introduction to the water issues in the Delta that definitely stimulates interest. The animated graphic that really caught my attention is the one that looks like blood being pumped through arteries, with pink and blue “cells” representing different water origin (I believe). I’m looking forward to hearing more.

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  4. Great video, I enjoyed it. Do you know of any contacts to run a Delta simulation? How would a shipping lock to protect the 3 bridges affect the Delta and the Salinity? Benicia has 3 bridges that span 1 mile across the straits and the shipping channel is constantly dredged to keep it deep but also allows a large amount of heavy salt water intrusion into the Delta. The shipping lock would only block about 1/12 of the straits, but I theorizes that this lock can block more than 20% of the salinity. With PPIC’s documentation that 71% of the water flows from the north are needed just to hold back the salinity, in theory this shipping lock can help the Delta environment and add more water in storage and export at the same time. This Lock is not a Dam, 11/12 of the straits would be open and free.

  5. Michael Miller says:

    Good intro to the Delta and some of the issues. I hope that when they start talking about the exports they take into account things like VAMP, the variable flow requirements for the tunnel project, the actual amount of export vs what the conceptions are and the economic benefit to the state that being able to export water when it’s in the system (winter) will have and the benefit the tunnels would be to the fisheries i.e. none of the endangered species will swim UP the Sacramento River where the do transverse the San Joaquin in the winter and spring. There are also other issues that need to be addressed like the fact that rip-rap is not a good source of food production or habitat and the trade off and who’s actually responsible for the levees under the Reclamation act that allowed for the establishment of the districts etc.

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  7. Tom Arthur says:

    Nice Video.

    Since it starts with natural water flows pre-1800s, I’d like to see a few statistics about how much flowed out the bay before man’s influence and how much flow’s out the bay now. I think we consume a little more than 50% of the historic average in a normal year? I really like how you tied the economy to the use of that water. However, I’d like to see/understand the big picture not just the agriculture picture of that use. I read ~80% is used for Ag and it produces 2% of California’s GDP? That leaves 20% of the water producing 98% of CA’s GDP? How we should prioritize our water usage becomes a clear question if overall economy is a justification for that use.

    I assume the future videos will begin to show the current reverse flows through the False River/Frank’s Tract and theory how the tunnels will hopefully solve some salinity issues? I hope you make clear/differentiate the idea of creating more stable marsh ecosystems vs exporting more total water from the delta via new tunnels. (this requires the first point above pre1800s water flow knowledge) I can’t help but think the tunnels are about exporting more water south, if not, why would southern water districts care/pay for tunnels? As Reddit would say, explaining it like I’m 5 years old (ETLI5) is critical for politicians, voters and tax payers to understand.

    Goal: Everyone should be able to follow the big picture money/water supply and demand and its effect on us and the environment. Thanks.

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