Reach 2B and Mendota Pool Bypass

Creating a passable San Joaqin River for salmonids between Mendota Dam and the confluence with Merced River is critical for the Program. In order to accomplish this, Reclamation must provided a fishway to circumvent the Mendota Dam and Pool, a large agricultural water diversion point. The Mendota Pool Bypass and Reach 2B Project will accomplish this by creating a river-like channel over a half-mile around Mendota Pool. By doing so, the Program will meet a key goal of providing volitional fish passage so salmon and other anadromous fish can complete their lifecycle while allowing water deliveries to farms continue. Other characteristics of the project include set-back levees to create floodplain habitat. Below is a schematic map showing the Reach 2B Project.

A description of the inset, depicting the major project appurtenances:

  • Mendota Pool Bypass channel and levees
    • Provides unimpeded fish migration and 4500 cfs conveyance capacity
  • Reverse Flow Facility
    • Reduces Mendota Dam releases which causes false attraction for adult salmonids
  • Mendota Pool Bypass Control Structure & Fish Ladder
    • Enables Restoration Flow deliveries to Mendota Pool while providing upstream salmon passage
  • Fish Recapture Facility & Bypass Pipe
    • Allows for fish sampling, rescue, and downstream passage
  • Mendota Pool Fish Screen
    • Provides downstream passage for fish during Mendota Pool deliveries
  • South Wing Dam
    • Maintains Mendota Pool water surface elevation

In September 2021, the Program completed the first Reach 2B construction project  — the replacement of Mowry Bridge. Started a year earlier, this project replaced a condemned bridge spanning the Fresno Slough at the upstream end of the Mendota Pool. The bridge replacement serves several purposes for the Mendota Pool Bypass and Reach 2B Project including providing a haul route during construction as well as the primary operation and maintenance access point for the Reach2B control structures and the Mendota Pool Bypass. The project also provides another key benefit: a stable structure for the economically disadvantaged City of Mendota’s municipal water supply line – the City’s primary source of drinking water. The City oversaw the construction effort and key milestones are highlighted below.

L to R: Old bridge and encroaching vegetation; vegetation removal; building the crane pads.

L to R: Crane placing steel support piles for use during construction which will be removed following construction of the new bridge; attaching the old city water line temporarily to the support piles; continuing demolition of the concrete top of the old bridge.

L to R: Removing remaining concrete slabs from old bridge; starting removal of old wood structure; complete removal of an old bridge section.

L to R: Driving sheet piling in order to create the coffer dam needed to create dry working conditions during construction; driving the bridge support piles using a vibrating crane hammer; the rebar cages that will be placed into the support piles.

L to R: Inserting a rebar cage into a driven pile; rebar cages protrude from a pile following concrete pouring; a completed bridge support.

L to R: Completed bridge supports stand in the river following removal of the coffer dam; pre-cast concrete slabs lowered into place.

L to R: Rebar placed on the slabs; pouring the concrete deck.

L to R: Completing installation of the new city water line; the completed Mowry Bridge; aerial view showing the completed bridge spanning Fresno Slough.

Project Information

Project Map

NameCategoryDateYearKindSizeTags
Draft 508 MLT July 05 Summary And Photographs 093019 (1)Data-reportingSeptember 30, 2019pdf0 B
DEIS/R – Executive SummaryReach 2bAugust 14, 2017pdf4.2 MiB
DEIS/R – Chapters 1-6Reach 2bAugust 14, 2017pdf6.3 MiB
DEIS/R – Chapters 7-11Reach 2bAugust 14, 2017pdf6.3 MiB
DEIS/R – Chapters 12-16Reach 2bAugust 14, 2017pdf5.5 MiB
DEIS/R – Chapters 17-23Reach 2bAugust 14, 2017pdf4.4 MiB
DEIS/R – Chapters 24-30Reach 2bAugust 14, 2017pdf4.8 MiB
DEIS/R – Appendices Part 1Reach 2bAugust 14, 2017pdf4.8 MiB
DEIS/R – Appendices Part 2Reach 2bAugust 14, 2017pdf4.0 MiB
DEIS/R – Appendices Part 3Reach 2bAugust 14, 2017pdf6.1 MiB
Project Description Technical Memorandum (TM), October 2012Reach 2bAugust 14, 20172012pdf6.2 MiB
Environmental Field Survey Reports TM, November 2011Reach 2bAugust 14, 20172011pdf2.9 MiB
Regulatory Compliance TM, August 2011Reach 2bAugust 14, 20172011pdf1.3 MiB
Selection and Use of Analytical Tools TM, October 2010Reach 2bAugust 14, 2017pdf0.8 MiB
Initial Options TM, April 2010Reach 2bAugust 14, 20172010pdf2.9 MiB
Existing Environmental Conditions TM: Data Needs and Survey Approach, March 2010Reach 2bAugust 14, 20172010pdf3.0 MiB
Public Scoping Report, February 2010Reach 2bAugust 14, 20172010pdf0.3 MiB
Public Scoping Report Attachment A, February 2010Reach 2bAugust 14, 20172010pdf0.6 MiB
Public Scoping Report Attachment B, February 2010Reach 2bAugust 14, 20172010pdf12.8 MiB
Public Scoping Report: Attachment C, February 2010 Reach 2bAugust 14, 20172010pdf18.1 MiB
Federal Notice of IntentReach 2bAugust 14, 2017pdf42 KiB
State Notice of PreparationReach 2bAugust 14, 2017pdf0.6 MiB
Press Release – July 13, 2009 (Español)Reach 2bAugust 14, 20172009pdf0.1 MiB
Fresno Slough Dam, Narrow Flood PlainReach 2bAugust 14, 2017pdf2.9 MiB
Fresno Slough Dam, Wide Flood PlainReach 2bAugust 14, 2017pdf2.9 MiB
Compact Bypass and Wide Flood PlainReach 2bAugust 14, 2017pdf2.9 MiB
Compact Bypass and Narrow Flood Plain, South CanalReach 2bAugust 14, 2017pdf2.8 MiB
Reclamation Memo Regarding Floodplain Habitat Related to AlternativesReach 2bAugust 14, 2017pdf90 KiB
United States Fish and Wildlife Service – Endangered Species Act: Biological Assessment – February 24, 2016Reach 2bAugust 14, 20172016pdf6.0 MiB
United States Fish and Wildlife Service – Endangered Species Act: Transmittal Letter – February 24, 2016Reach 2bAugust 14, 20172016pdf60 KiB
United States Fish and Wildlife Service – Endangered Species Act: Biological Opinion – August 9, 2016 Reach 2bAugust 14, 20172016pdf2.3 MiB
United States Fish and Wildlife Service – Fish and Wildlife Coordination Act Report – May 24, 2016Reach 2bAugust 14, 20172016pdf8.8 MiB
National Marine Fisheries Service – Endangered Species Act: Programmatic Biological Assessment – March 14, 2016Reach 2bAugust 14, 20172016pdf15.5 MiB
National Marine Fisheries Service – Endangered Species Act: Transmittal Letter – March 14, 2016Reach 2bAugust 14, 20172016pdf45 KiB
Programmatic Biological Opinion – October 24, 2016Reach 2bAugust 14, 20172016pdf5.5 MiB
Columbia Canal Intake and Siphon Biological Assessment – December 6, 2016Reach 2bAugust 14, 20172016pdf0.8 MiB
United States Army Corps of Engineers – Section 404 Permit: Preliminary Jurisdictional Determination – January 24, 2017Reach 2bAugust 14, 20172017pdf3.2 MiB
Compact Bypass 90% Hydraulic Design Report – March 2017Reach 2bAugust 14, 20172017pdf29.8 MiB
Compact Bypass 60% Hydraulic Design Report – November 2016Reach 2bAugust 14, 20172016pdf6.6 MiB
Compact Bypass 30% Design Hydraulic Report – October 2015Reach 2bAugust 14, 20172015pdf8.5 MiB
Conceptual Hydraulic Design Technical Report – August 2015 Reach 2bAugust 14, 20172015pdf4.8 MiB
Conceptual Hydraulic Design Technical Report: Appendix A – August 2015 Reach 2bAugust 14, 20172015pdf0.2 MiB
Conceptual Hydraulic Design Technical Report: Appendix B – August 2015 Reach 2bAugust 14, 20172015pdf14.5 MiB
Conceptual Hydraulic Design Technical Report: Appendix C – August 2015 Reach 2bAugust 14, 20172015pdf3.9 MiB
Geomorphic Analysis – April 2011Reach 2bAugust 14, 20172011pdf3.6 MiB
Vegetation Modeling – January 2011Reach 2bAugust 14, 20172011pdf4.6 MiB
Aug 12 SJRRP R2B landowner Meeting PresentationReach 2bJanuary 10, 20172015pdf3.3 MiB
Aug 12 R4B Landowner Meeting AgendaReach 2bJanuary 10, 20172015pdf50 KiB
Draft EIS/R AlternativeD MapReach 2bJanuary 10, 20172015pdf2.6 MiB
Draft EIS/R Preferred AlternativeB MapReach 2bJanuary 10, 20172015pdf2.6 MiB
July 10 MPB Draft EIS/EIR Meeting Sacramento AgendaReach 2bJanuary 10, 20172015pdf45 KiB
July MPB Draft EIS/EIR Meeting AgendaReach 2bJanuary 10, 20172015pdf0.2 MiB
Feb 12 Reach 2B Project Hydraulic and Sediment Transport Modeling WorkshopReach 2bJanuary 10, 20172015pdf45 KiB
SRH-2015-26 Appendix BReach 2bDecember 21, 20162015pdf14.5 MiB