City of Union City-Public Works Department
Line M Detention Basin-Pump Station, City Project No. 03-25 Initial Excavation, Development and Maintenance Memo
Prepared July 21, 2025
Initial Excavation
In the early 2000’s, excavation was done along the alignment of the future State Route 84 within the PSSC site between the Niles Subdivision and the BART trackway/Oakland Subdivision as a way to mine or generate clean fill for remediation of the site and to address Caltrans comments about encountering hazardous materials within the future State Route 84 right of way during the preparation of the State Route 84 EIR/EIS. This excavation work was approved by the California Department of Toxic Substances Control (DTSC).
Development of the Detention Basin
After the excavation of the future State Route 84 area was completed, the City, in coordination with the developer, discussed using the excavated area as a temporary drainage basin. The Line M Detention Basin-Pump Station, City Project No. 03-25 was initiated in 2003 with project completion by June 2005. This interim project served the following purpose before the anticipated construction of the future Route 84 project by 2010:
1) Serve as temporary site and roadway storm water detention basin for the adjacent KB Homes development during a storm event. When the water surface level in the nearby Line M Flood Control Channel drops to a certain level, the pump station in the Line M Detention Basin automatically turns on and discharges the storm water in the basin directly into the channel. 2) Because Line M Channel did not have sufficient capacity, the City agreed to allow the Alameda County Flood Control District to utilize this detention basin to serve as an overflow basin. When the water surface reaches certain levels during major storm event in the channel, the stormwater drains directly into the detention basin.
3) The design of this detention basin included a ramp down to the bottom of the basin to allow equipment access for maintenance of the detention basin.
The Detention Basin plan sheet shows the grading, the pump station, the gravity line from Line M Channel and access ramp. See plan below.
Maintenance of the Detention Basin
The Public Works Grounds Crews performs routine maintenance of the Line M Detention Basin area by cutting back weeds and grasses and specifically before the July 4th Holiday since Union City does allow the use of “Safe and Sane” Fireworks. They also pick up illegal dumping when reported.
From time-to-time homeless encampments have been reported at the top of the basin area, and the City contracts with specialized environmental cleanup contractors for cleanup of these encampments.
The Public Works Engineering Department maintains the pump station operations. Staff periodically turn on the pump to ensure it is operational, especially before a storm event. During and after a storm event, the Public Works Inspectors confirm the operations of the pump and will report back to City Hall in case the KB Townhome residents contact City Hall about the water level of the basin.
Public Works does not have separate, detailed maintenance records for the Line M Detention BasinPump Station as it is included in the overall annual maintenance budget and maintenance work is performed by City staff. However, based on research of available project files, phone calls and emails, the maintenance of the detention basin and the pump station is noted below with a few attachments.
Dates Description of Maintenance Responsible Staff
2005-2010 Maintenance Division- Cut and trim
weeds and grasses
Engineering Division-Check status of
pump operations
Phil Sachs, Grounds Supervisor (Retired)
Carlos Jocson, City Engineer (Retired)
and Public Works Inspector (John Marks
and Travis Golden, retired)
2010-2018 Same as above Nelson Kirk, Ground Supervisor
(Retired), Bill Bontadelli, Grounds
Supervisor (Retired)
Thomas Ruark, City Engineer (Retired)
and John Flood, Public Works Inspector
20218-2021 Same as above plus cleanup of
illegal dumping and coordinate
removal of homeless encampments
Bill Bontadelli, Ground Supervisor
(Retired) and Jesus Banuelos, Ground
Supervisor
Farooq Azim, City Engineer and John
Flood, Public Works Inspector
(Deceased)
2021-Present Same as above plus cleanup of
illegal dumping and coordinate
removal of homeless encampments
Jesus Banuelos, Ground Supervisor
Jose Gutierrez, Supervising Public Works
Inspector
ATTACHMENTS
Attachment A: Pacific States Steel Corporation Site Fact Sheet (Public Notice June 2003) Attachment B: Pictures of Pump Inspection (February 2012) Attachment C: Brief Maintenance Record from Public Works Inspector (2010-2011) Attachment D: Email from Supervising Inspector during “Atmospheric Storm” event (January 2023) Attachment E: Email from Ground Supervisor on Annual Maintenance (June 2025) ATTACHMENT A:
ATTACHMENT B:
Pictures of Pump Station Maintenance Record (by John Flood, Public Works Inspector (Feb 2012)
LINE M DETENTION BASIN/PUMP STATION
ATTACHMENT C:
Maintenance Record prepared by John Flood, Public Works Inspector
LINE M DETENTION BASIN/PUMP STATION
35902 Green Street Union City, Ca. 94587
2010/2011 Maintenance Record
May 2010 knocked down weeds and hauled away debris.
January 2011 Inspected pumps (2) pump cistern, detention pond inlet screen, and outlet pipe to Line M. Control panel operation normal, set to automatically alternate pumps with each use. All panels and vault lids secure and locked.
Fencing secured and locked. No Alarms!
June 2011 knocked down weeds and haul away debris. Remove litter in detention pond.
Trash separators on Platinum inspected and cleaned every four months. Debris and overgrowth removed around vault lids.
ATTACHMENT D
Email from Jose Gutierrez, Supervising Public Works Inspector on January 4, 2023 (Major Storm in 2023) From: Jose Gutierrez <[email protected]>
Sent: Wednesday, January 4, 2023 9:08 AM
To: Joan Malloy <[email protected]>; Marilou Ayupan <[email protected]> Cc: Tommy (Wai Chee) Cho <[email protected]>; Richard Tanaka <[email protected]>; Farooq M.
Azim <[email protected]>; Bob Calderon <[email protected]> Subject: Re: Line M Detention Basin and Line M Channel
Hello Joan and Marilou,
As of this morning at 8:00am the water levels of the Line M channel and detention basin remain approximately the same as yesterday at 5:00 pm. Some water from the Line M Channel is flowing into the detention basin but more of it is being pumped out than flowing in.
I turned the pumps off to give them a break and set them on auto, a few seconds later they started on their own because the water levels are above the set limit. The pumps are operating as designed.
Jose Gutierrez
Supervising Construction Inspector
City of Union City
(510)760-3542
ATTACHMENT E
Email from Jesus Banuelos, Public Works Grounds Supervisor on Annual Maintenance From: Jesus Banuelos <[email protected]>
Sent: Monday, July 21, 2025 9:05 AM
To: Marilou Ayupan <[email protected]>
Subject: M Line Detention Basin
Marilou,
For the last three years, the Line M Detention Basin maintenance has consisted of weed abatement, etc. and below is a summary of our maintenance operations.
Date Maintenance By Type of Labor
May 5, 2025 Contractor- Reynoso Tree Care Manual Weed Abatement & Other Clean Up June 6, 2024 Contractor- Reynoso Tree Care Manual Weed Abatement & Other Clean Up June 30, 2023 Public Works Ground Crews Rented Equipment (track mower) for Weed Abatement and Other Clean Up
We have contracted Reynoso Tree & landscape Services for our weed abatement over the last couple of years. They do all weed abatement and debris clean up in the Green St Detention Basin and 11th St Hill Cap by the 4th of July deadline.
Other years before contracting with Reynoso, we rented equipment and did all weed abatement in house.
If you need more details, let me know.
Regards,
Jesus Banuelos
Ground Supervisor.
Jesus Banuelos
Public Works Grounds Supervisor, City of Union City
Office: 510.675.5422 Cell: 510.737.1271
34009 Alvarado-Niles Rd
Union City • CA • 94587
www.unioncity.org