Storm Drain CIP Projects: Capacity Upgrades along East Meadow Drive and Connection to Adobe Creek Pump Station from East Meadow Circle (SD-22000 & SD-26000)

General work description: This project is comprised of two Storm Drain Master Plan CIP projects, the East Meadow Drive East of East Meadow Circle to Adobe Creek Pump Station Project (East Meadow Drive) and East Meadow Circle North of East Meadow Drive Project (East Meadow Circle). The Storm Drain Master Plan identifies both projects as a high-priority improvement to the City’s storm drain system. The first project location is on East Meadow Drive where the existing 36-inch pipe on East Meadow Drive is currently undersized and lacks the capacity to convey a 10-year storm runoff to the Adobe Pump Station. This project proposes to upsize the pipe to a 48-inch pipe to achieve a 10-year level of service. The second project on East Meadow Circle requires changes to the existing storm drain system by creating a bypass to allow flows from Barron Creek to overflow to the Adobe Creek pump station. The existing storm drain pipe lacks the capacity to convey a 10-year storm runoff. The proposed bypass proposes to add a new storm drain line to connect to the existing manhole on East Meadow Circle and the existing manhole on East Meadow Drive. This bypass will divert partial storm drain runoff to Adobe Creek during a storm event when water level on Barrow Creek is higher than that flap gate and flows within the pipes are not able discharge into Barron Creek. Additional storm drain work for the Storm Drainage System Replacement and Rehabilitation Project (SD-06101) is proposed to address locations where a storm drain pipe failed during recent storm events as a bid alternate. Over the past several years, Public Works Operations Maintenance group have compiled an ongoing list of storm drain pipes and structures that are in need of repair and/or replacement. Over time, the pipes have cracked due to age, tree roots, construction activities, etc. and in some cases, pipe material such as corrugated metal pipe (CMP) has rusted, rotted where there are holes in the pipes. Some of the rusted pipes have large holes on the sides of the pipes and collapsed on itself. There are several locations throughout the City where storm drain pipes failed during the past storms and will require replacement. Due to the complexity of work required, the repair cannot be completed by City of Palo Alto Public Works Operations group. To preserve the integrity of the storm drain system, these pipes need to be repaired. The purpose of the replacement is to preserve, if not improve, the integrity of the storm drain system.