LAMORINDA WEEKLY | Moraga Road drainage improvements slowly on track for Rheem intersection


Flooding last winter at the end of the existing turnout along northbound Moraga Road. Photo courtesy Public Works Dept.

Last winter’s substantial rains created havoc on the town’s roadways, but the Moraga Road and Rheem Boulevard intersection always seems to pay a heavy price when it comes to flooding.
The street directly below what locals have dubbed Painted Rock, but is officially titled John Muir Land Trust Painted Rock Open Space, typically bears the brunt from inclement weather, and even the existing 9-inch Asphalt Concrete Berm, designed to keep runoff from pouring over into the Lafayette-bound lanes, has proven insufficient to hold back the flood waters from pooling onto the 500-foot stretch of Moraga Road between Dolores Street and Hansen Court.
The town awarded an engineering design services agreement to CSG Consultants, Inc. (Pleasanton) in February 2022, in the amount of $57,500 to complete their agreement by the end of October 2022. In April, CSG’s subconsultant, LSA Associates, Inc., determined that the area where the runoff was being trapped could potentially be wetlands. In July 2022, the U.S. Army Corp of Engineers (USACE) verified and agreed with the assessment, to which CSG began developing stormwater improvement concepts that would allow construction outside of the wetland area.
The project suffered delays due to analyzing multiple layouts for vehicle, bicycle, and storm drain improvement concepts within the limited existing pavement width. During this time, the town’s project manager departed, and replacement staff needed to be recruited and brought up to speed. This delay increased the engineering design hours.
Back on track again, staff has proposed two feasible project design options according to a Sept. 27 staff report by Public Works Director/Town Engineer Shawn Knapp and Associate Civil Engineer Edrianne Aguilar. The first option is to “collect and convey stormwater runoff to the existing drain inlet by constructing either a dirt or concrete swale [a low or hollow place] outside the existing pavement, potentially impacting the proposed wetlands area. For the town to construct within the dirt shoulder, either USACE will need to officially move or remove the proposed wetlands area, or the Project will need to provide mitigation measures per permitting agencies.”
The second option is to “collect and convey stormwater runoff to the existing drain inlet by replacing the existing AC Berm with a taller concrete Berm intended to retain runoff from overtopping.”
Moraga’s staff has requested to be present during a second USACE site visitation to determine their next course of action as to whether the AC Berm can be eliminated or moved.
In the meantime, the town council has approved a $17,490 increase to CSG’s originally contracted $57,500 for a new total amount not to exceed $74,990 in order to complete the additional engineering design services.