This year our restoration project is located at El Manto, just a short jog down from the 2016 site, Sacramento Bar. Late May, cbec started the pre-project survey and we hope to have a preliminary design for our project team to review next month.

Looking downstream to the project

The design will include a side channel carved in the southern bank for rearing habitat, with the excavated materials placed into the river for spawning habitat (to the left). Due to the wet year, we hope to be in the river during September when the flows will be down to 3,500. We also plan on jumping downstream of San Juan Rapids (picture to the right) to fix a stranding problem from a backwater area.

Downstream of El Manto and San Juan Rapids (off to the left). This backwater presents stranding issues, and we are planning on doing some light grading to fix that.

El Manto and San Juan Rapids at 35,000 cfs

During the high flows this winter, we were able to get this aerial of the inundated at 35,000cfs.

When designing a project, we aim to understand all aspects and possible consequences. We use many methods of data collection to get a handle on optimum design for fish and to model flood control. Mary Maret, from Sacramento County Parks, joined us to identify rare populations of native plants for so we could try to avoid them during design. cbec conducts a series of surveys and other data collection techniques in order to build a robust and accurate model of the existing condition. As with each of these projects, we aim to make only positive changes in the landscape.

cbec has installed stage monitors to validate their model by collecting depth information over time for different flows. To the left is Ben Taber collecting bathymetric RTK GPS elevation data. They also collected foot and drone based topographic data. A 2D hydraulic model will be developed and used to design the best habitat suitability (depth and flow)

Keep an eye out in September for this exciting project!

Foothill penstemon. Penstemon heterophyllus

Date: Tue, May 23, 2017 at 10:02 AM
Subject: Nimbus Dam – Change Order

Please make the following release changes at Nimbus Dam:

Date               Time         From (cfs)      To (cfs)

05/24/2017      2000            9,500             9,100

05/24/2017      2100            9,100             8,700

05/24/2017      2200            8,700             8,300

05/25/2017      2000            8,300             8,000

05/25/2017      2100            8,000             7,650

05/25/2017      2200            7,650             7,300

05/26/2017       2000            7,300             7,000

05/26/2017       2100            7,000             6,700

05/26/2017       2200            6,700             6,400

Comment:  Reduce flows for Memorial Day weekend

Issued by:  P. Manza

Reclamation aims to fill the reservoir by late June, with a possible lowering to 5,000 – 6,000 cfs for Memorial Day weekend for boater & rafter safety.

Initial iCPMM modeling suggests that ATSP schedule 23 (64 degrees with one-degree buffer at Watt Avenue) can be achieved. This is based on all upper shutters being lowered. Currently only the lower and middle shutters are lowered units 1 and 2 (unit 3 is our for maintenance). The upper shutters are not in place because of a large amount of debris. This will impact the cold water pool if not resolved. Divers may be able to clear the debris, but that is not known.

May – Sep Storage & Flow Projection

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