Berkshire Creek Area Improvements Project

4550 Oak Grove Drive


The proposed Project site includes approximately 4.7 acres within the Oak Grove area of the City of Pasadena’s (City’s) approximate 1,300-acre Hahamongna Watershed Park (HWP). The Oak Grove area is situated in the southwestern portion of the Hahamongna Watershed Park Master Plan (Master Plan) area; and the Master Plan area is, in turn, an approximate 300-acre portion of the HWP that includes open space extending northward from Devil’s Gate Dam into the Arroyo Seco Canyon.

The primary goal of the Project is to improve the ecological, hydrological, and recreational conditions throughout the lower third of the Oak Grove area. This would be achieved by addressing the degraded conditions downstream of the Berkshire Place Storm Drain No. 12 storm drain outlet (Berkshire Drain); replacing asphalt with a permeable surface and native meadow garden at the equestrian picnic area; installing interpretive signage; and conducting riparian, oak woodland, and California sage scrub habitat restoration.

The Project proposes to implement the HWP Master Plan recommendation that the Berkshire Drain outlet location be extended downstream allowing the damage to the creek, downstream of the current outlet, repaired. The proposed engineering concept would replace the existing 30-inch-diameter drain pipe beneath the surface road with two separate drain pipes with different sizes, lengths, angles, and outfall locations, one for low flows and one for high flows. After installation of the replacement storm water infrastructure, the creek bed would be raised through placement of soils to repair the incised canyon and provide slope stabilization in preparation for habitat restoration. This engineering concept would stabilize Berkshire Creek and create sustainable long-term hydrologic conditions consistent with the hydrologic regime present in the Berkshire Creek watershed prior to land development (i.e., impervious surfaces). In addition to the engineering concept to manage outlet flow rates and locations at Berkshire Creek, a multi-use (i.e., pedestrian and equestrian) bridge crossing would be installed that would remain above storm water flows year-round.

The proposed Project would be constructed beginning in Fall 2019 over a period of three months and would be completed in a single phase. Project construction would occur from Monday through Saturday, without activity on Sundays or federal holidays, within an 8-hour period between the hours defined in Section 9.36.070 of the City of Pasadena Municipal Code (PMC) (7:00 AM to 7:00 PM Monday through Friday and 8:00 AM to 5:00 PM on Saturday).

Berkshire Creek Regional and Local Vicinity Map from MND


The City of Pasadena has completed an Initial Study (IS) and proposed Mitigated Negative Declaration (MND) for the Project.  The IS/MND and corresponding Notice of Intent to Adopt an MND can be downloaded from the following links.



City Council approval is needed for adoption of the Initial Study and Mitigated Negative Declaration and award of the Project construction contract. Urban Forestry Advisory Committee review is needed for public tree removal. Dates for these approvals and reviews have not been set.

A presentation on the Project will be part of the next regular meeting of the Hahamongna Watershed Park Advisory Committee at 6 PM on May 28, 2019 at the Pasadena City Yards, 233 West Mountain Street, 2nd Floor, Pasadena, California.

CASE MANAGER: Brent Maue, Assistant City Engineer (Public Works)