News & Operations Blog

Managing Cordova Creek: Staying ahead of Star Thistle

A native to Mediterranean Europe, the yellow star thistle (Centaurea solstitialis) made its way to California during the mid-19th century, likely via Chile through contaminated alfalfa mixes. With the lack of natural herbivores, the star thistle has the ability to create monotypic stands along disturbed landscapes. Their voracious nature eliminates and prevents other plants from growing, which degrades ecosystems and acts as a physical barrier for animal and human movement in wild spaces. Currently, it is estimated that star thistle occupies over 15 million acres of California’s floristic zone, and Cordova Creek, along with the American River Parkway, is no exception.

An unseasonably wet winter ‘16-17, hot summer, and the recently disturbed soil from Cordova Creek’s construction, all aligned to create an ideal habitat for star thistle to thrive in. As a result, the population exploded to an unprecedented level that the Water Forum and our partners were unprepared to fully manage. However, we are using the knowledge that we learned from last year’s experience to guide our current management strategies.

Starting in April, work crews have diligently hand-pulled and removed thousands of young star thistle growing throughout Cordova Creek. Despite their hard work, star thistle persistently exists in a few problem areas. To help address these problem areas, the Cordova Recreation & Park District and Soil Born Farms kindly agreed to each donate a day of mowing at Cordova Creek. Mowing star thistle can be extremely effective as a removal technique if timed correctly – once the plants have matured, bolted, and are at ~10% flowering. Mowing during this critical period prevents seeds from developing, and, without rain, the plants will be unable to regrow and flower this season.

We appreciate the help of both Cordova Parks and Recreation and Soil Born Farms to eliminate star thistle. We are confident that the combined efforts will ensure the success of Cordova Creek and the immense amount of ecosystem services that it provides to the community.

For more information on how to manage star thistle in your own area: Yellow Star Thistle Management Guide

A Day on the Farm

Posted on Thursday, May 31st, 2018

A Rock-ing Day on the Farm

All photos in this post are copyright Joan Cusick Photography.

Over 1,000 visitors explored Soil Born Farms during what’s become a regional favorite event, “A Day on the Farm.” Soil Born annually coordinates this event to celebrate the seasonal opening

of their farm stand and allow visitors a chance to learn more about the farm and its surrounding environment, eat local food, play, and create.

The Water Forum hosted a booth at Farm Day, to highlight Cordova Creek and emphasize its abundant resources and unique history. As you might recall, from 2014-2017 the Water Forum collaborated with multiple organizations, including


Soil Born, to naturalize Cordova Creek which had previously been a cement-lined drain. Though only a year since completion, the native plants continue to grow and mature, and a charismatic beaver has built a dam and made Cordova Creek its home. Though the Water Forum and  Sacramento County Regional Parks are coordinating the maintenance in the early years, Soil Born Farms is poised to be the stewards of the creek.

In addition to raising awareness of the creek, the Fellows lead a children’s rock painting

booth. The perpetually crowded booth soon became enveloped in rocks of all colors and designs – unicorns, basketballs, marbleized, narwhals, and more! They were able to paint rocks to keep and to donate to Cordova Creek. Since Cordova Creek is only a year old, many of the plants are still quite young. To ensure that they grow big and strong, we want to make sure that they are visible. The rocks that the community helped decorate will be placed around the native plants as a border. The colorful, painted rocks will make them stand out so that they do not get accidentally stepped upon, pulled out, or mowed.

Next time you visit Cordova Creek, be on the lookout for colorful rocks sprinkled along the trail!

Change Order

Posted on Thursday, May 24th, 2018

Date: Wed, May 23, 2018 at 9:54 AM
Subject: Nimbus Dam – Change Order

Please make the following release changes to the American River at Nimbus:

Date Time From (cfs) To (cfs)
5/26/18 0800 3,000 3,500

Comment: Delta Salinity

Issued by: Peggy Manza

Change Order

Posted on Tuesday, May 22nd, 2018

Date: Tue, May 22, 2018 at 9:52 AM
Subject: Nimbus Dam – Change Order

Please make the following release changes to the American River at Nimbus:

Date         Time    From (cfs)      To (cfs)

5/24/18       0800      2,500            3,000

Comment:  Delta Salinity

Issued by: Peggy Manza

Change Order

Posted on Friday, May 18th, 2018

Date: Thu, May 17, 2018 at 2:46 PM
Subject: Nimbus Dam – Change Order

Please make the following release changes to the American River at Nimbus:

Date         Time    From (cfs)      To (cfs)

5/22/18       0800      1,750            2,500

Comment:  Delta Salinity

Issued by: Peggy Manza


Sutterville Elementary School Science Night

Posted on Wednesday, May 9th, 2018

Sweet Science at Sutterville Elementary School Science Night 


Amid hand-made solar system displays, shoeboxes transformed into rainforests, caverns, colorful coral reefs, and other miniature habitats, and a few slime-making booths, our Water Fellows Kat and Cassie set up a table focused on Chinook salmon life cycle in the Lower American River.

Sutterville Elementary School hosts a large Science Night for students and their families annually. The night is a chance for the students to show off their science projects and learn from local scientists. Kat and Cassie spent the evening talking with students explaining the salmon lifecycle, the importance of gravel, and the Water Forum’s restoration projects in the Lower American River. After listening to the fellows speak, the students had the opportunity to make their own candy redds, using chocolate rocks, gummy fish, and nerds to symbolize salmon eggs! They also had the chance to observe preserved salmon eggs and their development, kindly lent to the Water Forum for the night from the Nimbus Hatchery.

The event created a space to spark curiosity and an early interest in science for the young learners, provide examples of scientific careers, and to ameliorate understanding of how the world fits together so that we can all care for it accordingly.

Change Order

Posted on Friday, May 4th, 2018

Date: Thu, May 3, 2018 at 9:34 AM
Subject: Nimbus Dam – Change Order

Please make the following release changes to the American River at Nimbus:

Date             Time           From (cfs)           To (cfs)
5/07/18        2100           2,000                   1,900
5/07/18        2200           1,900                   1,800
5/07/18        2300           1,800                   1,750

5/10/18        0800           1,750                   2,500
5/10/18        0900           2,500                   3,500

5/11/18        2100           3,500                   3,400
5/11/18        2200           3,400                   3,300
5/11/18        2300           3,300                   3,200
5/12/18        0000           3,200                   3,100
5/12/18        0100           3,100                   3,000

5/12/18        2100           3,000                   2,900
5/12/18        2200           2,900                   2,800
5/12/18        2300           2,800                   2,700
5/13/18        0000           2,700                   2,600
5/13/18        0100           2,600                   2,500

5/13/18        2100           2,500                   2,400
5/13/18        2200           2,400                   2,300
5/13/18        2300           2,300                   2,200
5/14/18        0000           2,200                   2,100
5/14/18        0100           2,100                   2,000

5/14/18        2100           2,000                   1,900
5/14/18        2200           1,900                   1,800
5/14/18        2300           1,800                   1,750

Comment: pulse flow operation, coordinated with fisheries agencies

Issued by: Peggy Manza

The pulse flow accompanies the May 10th hatchery release of juvenile Chinook. This schedule results in a net water balance by dropping to the minimum river release (MRR) before and after the pulse.