--- title: Between the Trees Blog | cofferdam description: cofferdam | Our official blog including Brennan company news, videos, and project overviews from the field. image: https://www.jfbrennan.com/hubfs/home_page/Between-the-trees-blog.jpg --- [MENU **](https://www.jfbrennan.com/blog/topic/cofferdam#mobile-nav) Submit - ** - [About Us](https://www.jfbrennan.com/about-us) - History - [Culture](https://www.jfbrennan.com/culture) - [Contact Us](https://www.jfbrennan.com/contact-us) - [Blog](https://www.jfbrennan.com/blog) - [Careers](https://www.jfbrennan.com/careers) - [Why Brennan?](https://www.jfbrennan.com/careers/why-brennan) - [Benefits](https://www.jfbrennan.com/careers/professional-and-technical) - [Current Openings](https://www.jfbrennan.com/careers/current-openings) - Online Application - [Brennan Gives Back](https://www.jfbrennan.com/givesback) - [Plan Room](http://www.brennanopr.com/) [![J.F. Brennan Company, Inc.](https://www.jfbrennan.com/hubfs/images/j-f-brennan-company-logo-horizontal.png) ![J.F. Brennan Company, Inc.](https://www.jfbrennan.com/hubfs/images/j-f-brennan-company-logo-horizontal.png) ](https://www.jfbrennan.com/) - [Environmental](https://www.jfbrennan.com/environmental) - [Dewatering Services](https://www.jfbrennan.com/environmental/separation-and-dewatering) - [Environmental Dredging](https://www.jfbrennan.com/environmental/environmental-dredging) - [Hydraulic Dredging](https://www.jfbrennan.com/environmental/hydraulic-dredging) - [Mechanical Dredging](https://www.jfbrennan.com/environmental/mechanical-dredging) - [Amphibious Dredging](https://www.jfbrennan.com/environmental/amphibious-dredging) - [Diver-Assisted Micro Dredging](https://www.jfbrennan.com/environmental/diver-assisted-micro-dredging) - [Material Transport](https://www.jfbrennan.com/environmental/material-transport) - [Hydrographic Survey](https://www.jfbrennan.com/environmental/hydrographic-survey) - [Habitat Restoration](https://www.jfbrennan.com/environmental/habitat-restoration) - [Isolation Barriers](https://www.jfbrennan.com/environmental/isolation-barriers) - 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[Dredging](https://www.jfbrennan.com/marine-construction/dredging) - [Underwater Inspections & Survey](https://www.jfbrennan.com/marine-construction/underwater-inspections-and-survey) - [Dive Inspections](https://www.jfbrennan.com/marine-construction/dive-inspections) - [Acoustic Imaging](https://www.jfbrennan.com/marine-construction/acoustic-imaging) - [Hydrographic Survey](https://www.jfbrennan.com/marine-construction/hydrographic-survey) - [Side Scan Sonar](https://www.jfbrennan.com/marine-construction/side-scan-sonar) - [ROV](https://www.jfbrennan.com/marine-construction/rov) - [Underwater Construction](https://www.jfbrennan.com/marine-construction/underwater-construction) - [Maritime Security Barrier Systems](https://www.jfbrennan.com/maritime-security-barriers) - [Bridge Construction](https://www.jfbrennan.com/marine-construction/bridge-construction) - [Construction & Replacements](https://www.jfbrennan.com/marine-construction/construction-and-replacements) - [Piers & Abutments](https://www.jfbrennan.com/marine-construction/piers-and-abutments) - [Scour & Erosion](https://www.jfbrennan.com/marine-construction/scour-and-erosion) - [Protection Systems](https://www.jfbrennan.com/marine-construction/protection-systems) - [Marine Support](https://www.jfbrennan.com/marine-construction/marine-support) - [Dam Construction](https://www.jfbrennan.com/dam-construction) - [Concrete Placement](https://www.jfbrennan.com/dam-construction/concrete-placement) - [Mass Pours](https://www.jfbrennan.com/dam-construction/mass-pours) - [Concrete Repairs](https://www.jfbrennan.com/dam-construction/concrete-repairs) - [Precast Components](https://www.jfbrennan.com/dam-construction/precast-components) - [Preplaced Aggregate Concrete](https://www.jfbrennan.com/dam-construction/preplaced-aggregate-concrete) - [Grouting](https://www.jfbrennan.com/dam-construction/grouting) - [Leave in Place Formwork](https://www.jfbrennan.com/dam-construction/leave-in-place-formwork) - [Gates and Actuators](https://www.jfbrennan.com/dam-construction/gates-actuators) - [Intakes & Headworks](https://www.jfbrennan.com/dam-construction/intakes-and-headworks) - [Underwater Inspections & Survey](https://www.jfbrennan.com/dam-construction/underwater-inspections-and-survey) - [Dive Inspections](https://www.jfbrennan.com/dam-construction/dam-inspection-diver-services) - [Acoustic Imaging](https://www.jfbrennan.com/dam-construction/acoustic-imaging) - [Hydrographic Survey](https://www.jfbrennan.com/dam-construction/hydrographic-survey) - [Side Scan Sonar](https://www.jfbrennan.com/dam-construction/side-scan-sonar) - [ROV](https://www.jfbrennan.com/dam-construction/rov-inspections) - [Underwater Construction](https://www.jfbrennan.com/dam-construction/underwater-construction) - [Cofferdams](https://www.jfbrennan.com/dam-construction/cofferdams) - [Scour & Erosion](https://www.jfbrennan.com/dam-construction/scour-and-erosion) - [Harbor Management](https://www.jfbrennan.com/harbor-management) - [Switching and Fleeting](https://www.jfbrennan.com/harbor-management/switching-and-fleeting) - [Barge Cleaning](https://www.jfbrennan.com/harbor-management/barge-cleaning) - [Dry Dock Vessel Repairs](https://www.jfbrennan.com/harbor-management/dry-dock-vessel-repairs) - [Short Haul Towing](https://www.jfbrennan.com/harbor-management/short-haul-towing) - [Marine Assists](https://www.jfbrennan.com/harbor-management/marine-assists) - [Contact Dispatch](https://www.jfbrennan.com/harbor-management/contact-dispatch) - [Customer Login](https://www.jfbrennan.com/customer-login) - [Railroad](https://www.jfbrennan.com/railroad) - [Bridge Construction](https://www.jfbrennan.com/railroad/bridge-construction) - [Construction & Replacements](https://www.jfbrennan.com/railroad/bridge-construction-and-replacements) - [Piers & Abutments](https://www.jfbrennan.com/railroad/piers-and-abutments) - [Scour & Erosion](https://www.jfbrennan.com/railroad/scour-and-erosion-repairs) - [Protection Systems](https://www.jfbrennan.com/railroad/bridge-protection-systems) - [Demolition](https://www.jfbrennan.com/railroad/demolition) - [Underwater Inspections & Survey](https://www.jfbrennan.com/railroad/underwater-inspections-and-survey) - [Culverts](https://www.jfbrennan.com/railroad/culverts) - [Environmental Response](https://www.jfbrennan.com/railroad/environmental-response) - [Marine Support](https://www.jfbrennan.com/railroad/marine-support) [MENU **](https://www.jfbrennan.com/blog/topic/cofferdam#mobile-nav) [![Temporary Cofferdam Portadam used for dewatering hydro dam](https://www.jfbrennan.com/hubfs/2023%20Portadam%20Install%20-%20Janesville%2c%20MN-214.jpeg) ](https://www.jfbrennan.com/blog/portadam-cofferdam-installation) ## [Portadam Installation at Hydro Dam: Innovative Solutions for a Changing World](https://www.jfbrennan.com/blog/portadam-cofferdam-installation) Posted by [Sam Stemper](https://www.jfbrennan.com/blog/author/sam-stemper) on March 04, 2024 We were contracted to replace flashboards and perform apron scour repairs at a hydroelectric dam along the Rock River in the Upper Midwest. Our client is a privately owned entity that owns and operates 80+ hydroelectric facilities throughout the United States. The project’s significant goals involved increasing the dam’s retainage capacity, protecting the existing spillway structure, and providing an aesthetically pleasing spillway for the community's residents. This project was scheduled for the summer months when flow rates are at their lowest, mainly due to the volatility of the Rock River and the need for a slow-moving current to keep our divers safe.  [Read More](https://www.jfbrennan.com/blog/portadam-cofferdam-installation) [**{count-facebook}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-twitter}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-linkedin}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**](https://www.jfbrennan.com/blog/topic/cofferdam#) [![Photograph of J.F. Brennan Company's harbor and dry dock](https://www.jfbrennan.com/hubfs/St.%20Croix%20Boat%20%26%20Packet%20-%20Avalon%20Paddle%20Boat-101.jpg) ](https://www.jfbrennan.com/blog/most-impactful-2023) ## [The Year's Best: Our Most Impactful Marine Industry Articles You Won't Want to Miss](https://www.jfbrennan.com/blog/most-impactful-2023) Posted by [Kimberly Walters](https://www.jfbrennan.com/blog/author/kimberly-walters) on December 22, 2023 This year, Brennan's [blog](https://www.jfbrennan.com/blog) posts garnered an impressive readership of over 27,000. An analysis of our most searched topics identified the most significant issues in the environmental and marine construction industries, including those most relevant to our company's operations. This leads us to the question: What **were **our industry's most frequently researched topics? We've examined Brennan's most popular articles of the year -- let's count them down! [Read More](https://www.jfbrennan.com/blog/most-impactful-2023) [**{count-facebook}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-twitter}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-linkedin}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**](https://www.jfbrennan.com/blog/topic/cofferdam#) [![Photograph of Big Sandy Dam - Brennan](https://www.jfbrennan.com/hubfs/Big%20Sandy%20Lake%20Dam%20Drone%20Shot%20for%20Blog.jpg) ](https://www.jfbrennan.com/blog/sandy-dam-rehabilitation) ## [Dam Rehabilitation and Operational Updates to 100-Year-Old Structure](https://www.jfbrennan.com/blog/sandy-dam-rehabilitation) Posted by [Kimberly Walters](https://www.jfbrennan.com/blog/author/kimberly-walters) on August 09, 2023 Sandy Lake Dam is owned by the United States Army Corps of Engineers (USACE), St. Paul District. The USACE identified that the original concrete structure needed repairs and improvements to address immediate safety concerns. Because the dam structure was more than 100 years old, the USACE used this as an opportunity to have Brennan rehabilitate the dam and update many of its operational features. Our new video shows you how we did it!  [Read More](https://www.jfbrennan.com/blog/sandy-dam-rehabilitation) [**{count-facebook}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-twitter}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-linkedin}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**](https://www.jfbrennan.com/blog/topic/cofferdam#) [![Brennan cofferdam and hydropower dam](https://www.jfbrennan.com/hubfs/Cofferdam%20Chris%20Rousseu.jpg) ](https://www.jfbrennan.com/blog/hydropower-dam-expert-renewable-energy) ## [Hydropower Expert Aims to Bridge Gap in Renewable Energy Market](https://www.jfbrennan.com/blog/hydropower-dam-expert-renewable-energy) Posted by [Kimberly Walters](https://www.jfbrennan.com/blog/author/kimberly-walters) on March 01, 2023 J.F. Brennan Company, Inc. ([Brennan](https://www.jfbrennan.com/)) announces the promotion of Christopher Rousseau, P.E., F. ASCE to Hydro and Renewable Energy Market Leader. Rousseau’s promotion is announced concurrently with Brennan’s strategic objective to further invest in renewable energy development. Rousseau will use decades of experience in hydroelectric generation working for Midwest-based utility, [Minnesota Power](https://www.mnpower.com/Environment/Hydro), to support the repair and rehabilitation needs of Brennan’s hydro dam clients. Catering to a huge need for early contractor involvement; Rousseau is bridging the gap between hydroelectric dam owners, engineers, and the contractor teams that perform inspections, maintenance, and rehabilitation work. [Read More](https://www.jfbrennan.com/blog/hydropower-dam-expert-renewable-energy) [**{count-facebook}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-twitter}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-linkedin}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**](https://www.jfbrennan.com/blog/topic/cofferdam#) [![Brennan working LaGrange Lock and Dam in 2019](https://www.jfbrennan.com/hubfs/LaGrange%202019.jpg) ](https://www.jfbrennan.com/blog/major-lock-rehabilitation-lagrange) ## [Executing Major Rehab on an Existing Lock in 105 Days](https://www.jfbrennan.com/blog/major-lock-rehabilitation-lagrange) Posted by [Brady Wateland, Project Manager](https://www.jfbrennan.com/blog/author/brady-wateland-project-manager) on March 18, 2021 80 years old and 35 years since its last rehab, [LaGrange](https://www.mvr.usace.army.mil/Missions/Navigation/Lock-and-Dam-Information/LaGrange-Lock-and-Dam/) Lock and Dam in Versailles, IL was in major need of rehabilitation. Brennan partnered with prime contractor Shimmick Construction ([Shimmick](https://www.shimmick.com/)) and the U.S. Army Corps of Engineers ([USACE](https://www.mvr.usace.army.mil/)) Rock Island District, along with hundreds of crew members, to execute quality repairs through the existing lock. [Read More](https://www.jfbrennan.com/blog/major-lock-rehabilitation-lagrange) [**{count-facebook}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-twitter}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-linkedin}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**](https://www.jfbrennan.com/blog/topic/cofferdam#) [![Brennan replacing a spillway wall at hydropower dam](https://www.jfbrennan.com/hubfs/DJI_0488.jpg) ](https://www.jfbrennan.com/blog/installation-of-new-spillway-wall-at-dam) ## [How We Installed a New Spillway Wall at a Private Hydropower Dam](https://www.jfbrennan.com/blog/installation-of-new-spillway-wall-at-dam) Posted by [Ian Radcliffe](https://www.jfbrennan.com/blog/author/ian-radcliffe) on November 16, 2020 102 years of lateral earth pressure and deterioration at Pisgah Dam caused its existing spillway wall to lean. Partnering with private dam owner [Otter Tail Power Company](https://www.otpco.com/about-us/), Brennan ensured their hydropower dam received necessary repairs. The project included concrete demolition and the replacement of the dam's north spillway wall over two years. [Read More](https://www.jfbrennan.com/blog/installation-of-new-spillway-wall-at-dam) [**{count-facebook}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-twitter}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-linkedin}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**](https://www.jfbrennan.com/blog/topic/cofferdam#) [![Brennan Wisconsin Xcel Project 2019 SCHERP and Excavator](https://www.jfbrennan.com/hubfs/Nelson%20Wisconsin%20Amphibious%20Equipment%20Job.jpg) ](https://www.jfbrennan.com/blog/most-searched-read-blog-topics-of-2019) ## [Most-Searched Blog Topics of 2019](https://www.jfbrennan.com/blog/most-searched-read-blog-topics-of-2019) Posted by [Kimberly Walters](https://www.jfbrennan.com/blog/author/kimberly-walters) on January 07, 2020 Brennan blog posts were viewed 13,622 times in 2019. Reviewing our most-searched blog topics helps us construct a list of the marine industry's most critical topics and those most pertinent to our company. So, what *were* the most-searched topics? [Read More](https://www.jfbrennan.com/blog/most-searched-read-blog-topics-of-2019) [**{count-facebook}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-twitter}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-linkedin}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**](https://www.jfbrennan.com/blog/topic/cofferdam#) [![Braced Cofferdam](https://www.jfbrennan.com/hubfs/Blog_Images/2018_08_21/CofferDam_Banner2.jpg) ](https://www.jfbrennan.com/blog/cofferdams-101-different-types-and-construction-methods-on-waterways) ## [Cofferdams 101: Different Types and Construction Methods on Waterways](https://www.jfbrennan.com/blog/cofferdams-101-different-types-and-construction-methods-on-waterways) Posted by [Dillon Hogan](https://www.jfbrennan.com/blog/author/dillon-hogan) on August 21, 2018 Working around water poses a plethora of challenges. There are always two parts of a water-based project, the above and below water sections. Access to the above water section is easy, however when working below the waterline access is not that easy. One of the more apparent issues is what do you do when the water is in the way of your work? One solution is to build a cofferdam. [Read More](https://www.jfbrennan.com/blog/cofferdams-101-different-types-and-construction-methods-on-waterways) [**{count-facebook}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-twitter}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**{count-linkedin}](https://www.jfbrennan.com/blog/topic/cofferdam#)[**](https://www.jfbrennan.com/blog/topic/cofferdam#) [All posts](https://www.jfbrennan.com/blog/all) ### Subscribe Here! ### Latest Blog Posts ### Posts by Topic - [Marine Construction (70)](https://www.jfbrennan.com/blog/topic/marine-construction) - [Corporate Culture (53)](https://www.jfbrennan.com/blog/topic/corporate-culture) - [Employee Engagement (50)](https://www.jfbrennan.com/blog/topic/employee-engagement) - [Great Place to Work (44)](https://www.jfbrennan.com/blog/topic/great-place-to-work) - [Environmental Dredging (41)](https://www.jfbrennan.com/blog/topic/environmental-dredging) - [J.F. 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