Arroyo Viejo Park Creek Restoration

Oakland, CA

Alameda County Public Works Agency
Summer/Fall 2001

Arroyo Viejo Park is located near 73rd Avenue between Bancroft and East 14th Street in Oakland, CA. Arroyo Viejo runs west through the park, exiting a concrete walled channel upstream and entering a pipe downstream. Most of the Arroyo Viejo watershed has been placed in a network of flood control channels and pipes under the neighborhoods of East Oakland.

Prior to construction, the channel was bounded by failing concrete and rock walls, with little evidence of past channel morphology. Furthermore, the park facilities immediately adjacent to the creek existed in a deteriorated condition, serving minimal use to the surrounding neighborhoods.

Designed by Wolfe Mason Associates of Oakland, this creek restoration and park construction project included demolition of existing park facilities and creek structures, creek channel realignment and structure installation, and installation of park amenities.

Hanford ARC (prime contractor) completed the demolition of an existing amphitheater, asphalt paths, and concrete stream structures. Tree removal and preparation (for use as wood chips and log stream structures) was subcontracted to Atlas Tree Surgery.

Once cleared, Hanford ARC excavated and graded the new 700 foot-long stream channel and surrounding uplands. The channel has a perennial flow, which required dewatering prior to construction. A gravity bypass was installed using a cofferdam and steel pipe routed in the channel. An active pump bypass was temporarily used to dewater the channel during installation of the gravity bypass. Additionally, regular pumping of subsurface flow was required throughout channel grading.

Approximately 3,000 yards of soil were removed from the site to allow for lower bank slopes. The lower sloped banks integrated into the park features will promote access to the restored stream environment by park users. Two vortex weirs and 200 feet of anchored log deflectors were installed to stabilize the channel bed and create the designed thalweg. The stream channel sinuosity was increased to allow for a lower gradient longitudinal section, reducing the risk of incision.

The newly cut banks were stabilized with coir fabric and willow cuttings. A mix of native plantings and conventional landscape plantings were installed on the stream banks and among the new park amenities. Four brush mattresses of willow whips and cuttings were installed to establish bank roughness in areas of transition from newly graded areas to existing slopes.

The old concrete amphitheater was replaced by a new concrete and decomposed granite amphitheater with a lower profile. Decomposed granite paths, picnic areas, a stream overlook, and a 70-foot pedestrian bridge encircle the newly restored stream channel, and allow many views of the stream environment. Several lawn areas were seeded and an extensive irrigation system was installed across the entire site, above the stream banks.