Town Lake Western Dam Replacement



The City of Tempe has replaced the inflatable rubber dam system at the west end of Tempe Town Lake with a new, hydraulically-operated steel gate dam. The system will be, when complete, the country's largest hydraulically-operated steel gate dam system. The new dam will be a reliable and cost-effective solution that is expected to last for decades. More than 20 technology alternatives were explored before choosing this system, which was found by experts to be the most safe, reliable, cost-effective and durable while allowing the lake to transition into a river during major water flow events.

Final Phase of Construction 

As part of the construction process, the water from Town Lake is being moved out of the lake and into the Salt River Project (SRP) Canal System so that crews can remove the previous dam. We are using a special pump to do this. It takes until about March 15 to move the water into the canal. While the water levels are low, we will check lake infrastructure and make any necessary repairs. 

See Construction Photos

Tentative Construction Schedule

● Water from Tempe Town Lake is moved into SRP Canals – This is happening now
● Removal of previous dam system and lake maintenance
● We return water to Tempe Town Lake 
● Tempe Town Lake reopens – April 30, depending on construction and weather

Stay Safe

For safety’s sake, please stay out of the empty lakebed during this time. It might seem like a tempting place to explore, but the lakebed is a muddy no trespassing zone. Stay out of the Town Lake Marina Safe Harbor as well.     

Tempe Town Lake will close for water activities until approximately April 30. This timeline could change depending on weather and construction progress. All parks and pathways around Town Lake are expected to remain open. All land-based events at parks around Tempe Town Lake will continue as planned. 

Our Water

Water is a precious resource. Being able to use the water from Town Lake was important to us. The water will become irrigation for parks and lawns and could have other urban irrigation purposes. When it's time to return water to Town Lake, SRP will give us water credits, saving us money, too.

Our Fish and Wildlife 

We are taking many steps to protect and preserve the fish and wildlife of Tempe Town Lake. Read more
- Not stocking fish as normal in fall 2015 in order to lower the number of fish that would need assistance.
- Removing the limit on the number of fish that people could catch at Town Lake.
- Moving a representative portion of some fish into protected areas of the lake that will retain water. There will be no fishing in this area as we want the fish to prosper.
- Monitoring pockets of water within the lake that contain fish, since fish can survive in small space for such short amounts of time.

There is no fishing and no trespassing in the Town Lake Safe Harbor at the Marina during this time. 

We understand that some fish may not make it through this time. Those fish will contribute the well-being of other animals. We have reached out to the Phoenix Zoo, World Wildlife Zoo and the Herpetological Society and hope to provide fish to them. 


We are proactively working to minimize the number of midge flies and mosquitoes in the lake area. We have an expert on board who has prepared an aggressive plan to treat for mosquitoes and other insects. 

Please be Patient

Tempe knows that Town Lake is a very popular place to visit in the spring. We thank you for your patience during this time as we secure the lake's long-term future with this new dam system.  

How the New Dam Will Work 

The steel gate system consists of eight fabricated steel gates mounted onto a new roller-compacted concrete foundation and new reinforced concrete spillway slab about 100 feet downstream from the existing dam.

Using hydraulic lifts, these gates can be lowered to allow storm waters to pass through and raised to capture the tail end of the flow to re-establish the lake.  About two feet of water can pass over the top of the gates while they are in the fully-upright position. 




Each gate is: 
106 feet long 
17 feet tall 
Weighs 260,000 pounds 

The new piers will be about nine feet wide on the upstream side and four feet wide on the downstream side. 

The new dam should be complete in April, pending weather conditions. 

In Tempe, we believe in shopping local and working with the best experts available. For this project, we have been able to do both. Contractors for this project include: 

Tempe-based PCL Construction is the prime contractor.
Phoenix-based Gannett-Fleming is the engineering consultant.
Steel Fab fabricated the gates with Phoenix-based Schuff Steel

Arizona Department of Water Quality
Army Corps of Engineers
Flood Control District of Maricopa County

The cost of this project, including removal of the previous dam system, is approximately $47 million.  

Beyond providing flood control to make our city safer and allow development, Town Lake has benefitted our city so far with about $1.5 billion of economic impact. Approximately 40,000 people work within a mile of Tempe Town Lake and 4,000 people live near its shores.

As a result of Town Lake, Tempe now hosts many world class events and people can take part in a variety of recreation opportunities. It has transformed a dry riverbed into beautiful, relaxing community gathering place known throughout the world.  

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Information Release Oct. 26: 

A selection of coverage about the dam replacement project
Horizon PBS/ KAET 8
Arizona Family TV 3
East Valley Tribune

Previous Tempe City Council Decisions
Nov. 7, 2013 – Council considers award of contract to hire PCL Construction to replace western dam
Council Meeting Agenda Item: 5B12
Contracts Document

Sept. 19, 2013 – Council awarded contract to manufacture steel gates
PDF - Dam Replacement
Council Meeting Agenda Item: 5B19
Contract T14-004-01

June 25, 2015 - Change Order
Council Meeting Agenda Item: 5B13

Inflatable Bladders Report

Project Updates

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