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The Rancho Murieta Community Services District provided information Tuesday about its pumping operations, the debris issue affecting the pumps used to divert water from the Cosumnes River, and the amount of time it will take to fill the reservoirs.

The CSD's response to drought conditions includes taking water from the river whenever flows exceed the 70 cubic-feet-per-second threshold. The CSD was able to pump briefly Feb. 1, the first time since the diversion season began Nov. 1, before river levels dropped again. The storm that occurred over the weekend raised river levels to levels that will allow for days of pumping.

In normal years, the CSD would wait until storm debris subsides and the river runs clear to begin pumping. But this isn't a normal year. "Due to the dire water situation, we have been directed to pump to storage as soon as water is available," Paul Siebensohn, director of field operations, explained in an email.

Siebensohn wrote that the pumps shut down when the diversion intake screens at the Granlees pump station became clogged and limited flow to the pumps.  "The pumps kept shutting off on Sunday due to the system plugging and tripping out the pumps," he wrote.

Here is Siebensohn's email: 

The District has been pumping water from the Cosumnes River since early Sunday morning, however the pumping has not been consistent due to plugging up of the diversion intake screens, hydraulically limiting the flow into the pumps and causing them to shut off.

Why two or more pumps did not run yesterday:

As an analogy for the water draw through the fine mesh intake screens at the Granlees pump station, consider what it would be like mixing a few pebbles and sand up in water and then pouring it through a coffee filter (normal pumping).  The flow would not be too bad.  Try again but mix up a scoop of soil, sand, leaves, sticks, aquatic plants, etc. and try to pour it through a coffee filter (pumping after a large rain event).  It won't flow well at all.

Also imagine what sort of scour you will get through your pump and within the pipelines with water flowing through the pump at high velocities.  It will "sand blast" the impellers and walls of the pumps, wearing down the steel and creating a loss in efficiency and possibly permanent damage.  We can't pump it we break the pumps, plus repair would be a long and costly.  This is why we typically allow the "first flush" of the river to pass by, along with not wanting to divert poor water quality water to our potable supply reservoirs.  Due to the dire water situation, we have been directed to pump to storage as soon as water is available.

Yes, we did test the pumps prior to the pumping.  I even set up the testing day with SMUD to avoid a peaking charge that would be assessed to our power bill due to the test.  The pumps worked fine.  Water quality was much better in the river too.

We also pressure washed the intake screens prior to the pumping season when the river was low, which we do each season.

The pumps kept shutting off on Sunday due to the system plugging and tripping out the pumps.  There is no alarm system there to notify staff when this occurs, so our Chief Plant Operator came in to babysit it to try to keep it running.  Why is there no alarm system there?  It is over a mile from the nearest phone line connection.

As of today, two 500hp pumps are consistently running as the river has cleared up a bit since yesterday.  Why not three today?  Because, we would run into the same issue as Sunday and yesterday.

Below is a table as of 2/5/2014 for estimated pumping times to fill the reservoirs.

Pump chart

Our goal, as always, is to top off our reservoirs to the top of the stop-logs to capture as much water as possible.

Bunky Svendsen's picture
Joined: 08/07/2007
Posts: 165
Post rating: 210

Keeping the screens clean

If you need me to stand there with a pressure washer to keep those screens clean in order that you can continue to pump into the reservoirs i will do so for free. Just call me.354-1259

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