Students from Professor William Berry's ES 125 class, Environments of the San Francisco Bay Area, have been volunteering in the garden for the past few weeks to work on the creek project. We have been clearing the invasive blackberries and Algerian ivy and other invasive species from the creek area to study the creek channel, and uncovering and assessing an earlier bank renovation. As we are clearing we have been mulching the area to slow the regrowth of weeds and to add organic matter to the very heavy clay soil. We have also been removing years of trash and debris that has washed in and blocked the flow of the creek.
The creek restoration project began about a year ago when we started removing Himalayan Blackberry bushes and Algerian Ivy from the creek bed and trees. The creek is an upper part of Cerrito Creek and is fed mostly by urban runoff when it rains. The creek fills at an alarming rate (see time lapse video). We wanted to see where this water was coming from, and assess the condition of the creek bed and creek bank. We soon uncovered a rotting bridge, an older restoration project done in the 1970's with retaining walls made of concrete bags, some pools that had been made, lots of chatter was strewn in the creek bed, some undercutting and erosion.
[nggallery id=12] PHD candidate Kristen Podolak and MLA candidate Jessica Ludy surveyed the creek that had been opened up by staff and volunteers to start to create a new plan for restoration. (download Kristen & Jessica's paper)
[nggallery id=11] Later Nathanial Behrends, Master of Landscape Architecture Candidate, from LA 227 Restoration of Rivers and Streams, after reviewing Kristin's work and evaluating the condition of the newly uncovered upper area recommended a series stepped pools for the creek to slow the water coming through the channel to decrease the cutting of the banks. (download Nathanial's paper)
[nggallery id=15] After more removal of berries on the upper part we then discovered the creek was blocked with silt and urban debris that was diverting it from the original channel and creating scouring and cuts in the upper part of the garden. We removed the debris and restored the water to the original channel. [nggallery id=13] A group called The Weed Warriors led by Susan Schwartz of Friends of Five Creeks came in recently to eradicate some of the blackberries. (view time lapse video of The Weed Warriors at work) As we clear more weeds from the creek new opportunities emerge.