Central Alabama Water (CAW) is undertaking a large project to prepare Lake Purdy Dam to serve customers for decades to come.
Latest Update
Press Release: Experts visit Lake Purdy Dam construction site, 11/5/2025
Press Release: Central Alabama Water conducts dye test at Lake Purdy Dam, 11/4/2025
Media Advisory: Central Alabama Water to conduct dye test at Lake Purdy Dam, 11/3/2025
Press Release: Central Alabama Water Board hires experts to review Lake Purdy Dam project, 10/29/2025
Press Release: CAW Board provides updates on Lake Purdy Dam project, 10/21/2025
Lake Purdy Dam presentation to CAW Board, 10/20/2025
November 2025 Update
- Completed two-thirds of the Left Training Wall vertical installation which used 42 cubic yards of concrete. The last section of the left training wall will connect the dam to the training wall. That section should be completed by early January 2026.
- Completed mapping of the left wall for cast-in-place concrete steps.
- Started site preparations for grouting and micropile subcontractor mobilization.
- Completed capturing the seeping water at the base of the dam and directing it away from the dam. This is to prepare for placing the first base layer of roller compacted concrete (RCC).
- Completed placement of left side backfill which used 72 cubic yards of concrete.
- Completed installation of #10 dowels and poured the first three steps which used 520 cubic yards of RCC. Each step is three feet high.
- Completed pouring the first eight concrete steps at the buttress which used 118 cubic yards of RCC. Each step is three feet high.
- Continued cleaning and placing dental concrete on the left slope in preparation for RCC.
Project Overview
Lake Purdy Dam and Reservoir are located in northern Shelby County. The original construction of the dam was completed in 1910. Another project in the late 1920s raised the dam to its current height. It’s a major drinking water source for a large portion of the CAW’s service area including Birmingham, Homewood, Hoover, Mountain Brook, Vestavia Hills and surrounding areas.
The CAW has begun Phase 1 of a project that seeks to strengthen and modernize Lake Purdy Dam. In Phase 1, engineers and contractors are installing buttresses and structural supports to strengthen the dam and help prevent water seepage. This phase of construction is expected to be completed in January or February 2026, weather permitting.
This web page is updated monthly to track progress and provide recent images and videos of the site.
Frequently Asked Questions (FAQs)?
Lake Purdy is a 990-acre reservoir owned by Central Alabama Water and is an important source of drinking water for customers. It has a capacity of 5.59 billion gallons of water.
The water from Lake Purdy that is treated at the Shades Mountain Filter Plant serves people living in Birmingham, Homewood, Hoover, Mountain Brook, Vestavia Hills and surrounding areas.
Lake Purdy was constructed between 1906-1910. From 1927-1929, the dam was raised 20 feet to its current height of 73 feet and length of 445 feet.
Lake Purdy is located in northern Shelby County, Alabama, along the Little Cahaba River.
The water stored in Lake Purdy is eventually sent to Central Alabama Water’s Shades Mountain Filter Plant located along U.S. Highway 280 in Birmingham. The water is filtered and treated and then delivered to Central Alabama Water’s customers.
Lake Purdy Dam was constructed more than 100 years ago. Just like any ageing structure, it requires regular maintenance and sometimes needs extensive renovations to make it safer and suitable for modern purposes. The last major work to improve the dam’s operation was completed in the 1970s. Water is seeping underneath the dam and the dam is not strong enough according to modern standards. This project will strengthen the dam and help prevent seepage. .
The CAW estimates construction on Phase 1 will be completed in April 2026.
We estimate it will cost $28 million to construct the buttresses and structural supports.
Who are our design and construction partners?
Central Alabama Water’s Engineering Department is leading the project with the help of several contractors. Here is a list of who is involved:
- Design Engineers
- Independent Support Services
- Bhate Geosciences – field services and material testing
- TTL and Sidney May PE – environmental compliance oversite
- Contractor
Videos of Construction Site
The Lake Purdy Dam rehabilitation project update, December 11, 2025.
First batch of roller compacted concrete (RCC) installed at Lake Purdy Dam, November 14, 2025.
First batch of roller compacted concrete (RCC) installed at Lake Purdy Dam, November 14, 2025.
Experts visit Lake Purdy Dam construction site November 5, 2025.
Central Alabama Water conducts dye test at Lake Purdy Dam November 4, 2025
Video of the Lake Purdy Dam construction site from October 14, 2025.
Video of the Lake Purdy Dam construction site from September 12, 2025.
Video of the Lake Purdy Dam construction site from August 14, 2025.
Video of the Lake Purdy Dam construction site from July 14, 2025.
Previous Updates
October 2025 Update
- Completed the structural concrete encasement of the two 36-inch Low Level Outlet pipes with 940 cubic yards of concrete.
- Completed commissioning of new batch plant for Roller Compacted Concrete (RCC).
- Completed the foundation concrete for the Left Training Wall and began installing rebar for the vertical wall.
- Continuing to capture the seeping water at the base of the dam and directing it away from the dam to prepare for placing the first base layer of RCC/Concrete.
- Completed drilling 46 bore holes on the right-side base of the dam to confirm bedrock depth location. This information will be used to develop the engineering solution to provide a foundation slab for RCC placement.
- Completed the first layer of leveling concrete (dental concrete) at the left side of the dam in preparation for the initial RCC layer scheduled for November 11, 2025.
- Started the first concrete steps at the buttress in preparation for placement of RCC.
- Completed removal of all trees and stumps on the right side of the dam.
- Completed the right-side soil retaining wall.
September 2025 Update
- Crews poured more than 305 cubic yards of structural concrete over the two 36-inch Low Level Outlet pipes. The remaining concrete is scheduled for completion by the middle of October.
- Paved approximately 2,300 feet of the construction access road with asphalt. The pavement is near the road’s intersection with Highway 119/Cahaba Valley Road and on the section of the road that is closest to houses. This will help minimize dust for homeowners and limit dust and debris along the highway.
- Installed a new batch plant to boost Roller Compacted Concrete (RCC) production capacity and enhance the quality of the RCC used on the dam.
- Continued rebar placement and formwork preparation on the Left Training Wall foundation. Concrete pouring is scheduled to begin in mid-October. The entire wall is expected to be completed by February 2026 for Phase 1.
- Completed the Little Cahaba River crossing to allow access to the right side of the dam.
- Began the water control phase of capturing the seeping water through drains at the base of the dam and letting it flow away from the dam to allow the first base layer of RCC/Concrete to be placed.
- Started dewatering of the work area near the dam where the RCC will be placed.
- Water quality monitoring system is installed to monitor water quality at upstream and downstream locations of the Little Cahaba River.
August 2025 Update
- Access road
- All excavation, backfill and culverts along the access road from Highway 119 to the dam have been completed.
- Completed the placement of 19,133 tons (13,700 cubic yards) of stone along the access road. The stone covers approximately 12,800 linear feet.
- Asphalt paving of the access road’s entrance at Highway 119 and paving of the portion of the road near houses will take place in September. The pavement will limit the amount of dust near the homes and along Highway 119.
- Low-Level Outlet
- Completed the tie-in of two permanent 36-inch pipes that will serve as a low-level outlet (LLO). The pipes allow Central Alabama Water to safely discharge water from the reservoir during construction.
- Completed the first structural concrete pour under the two 36-inch LLO pipes. The plan is to have the final LLO pipe concrete encasement completed by the end of September.
- Roller Compacted Concrete
- More than 3,750 cubic yards of material have been excavated and backfilled with 251 cubic yards of concrete in preparation for placement of Roller Compacted Concrete (RCC) to strengthen the dam.
- Completed the commissioning of the RCC batch plant, which has produced 260 cubic yards of test RCC. An RCC test pad is scheduled to start on September 11 to verify the quality of the RCC for buttressing of the dam.
- Other updates
- Began excavation and preparation for forming the Left Training Wall foundation. Concrete is scheduled to be poured by mid-October.
- Began construction of the Little Cahaba River crossing. The crossing will allow construction access to the right side of the dam. This project is scheduled to be completed in September.
July 2025 Update
- Completed widening of the two-mile access road.
- Installed 19 reinforced concrete pipe culverts along roadway to support drainage.
- Finished grading of the road.
- Completed stone placement along 1,715 linear feet of the roadway.
- Currently installing 500 linear feet of stone per day.
- More than 2,500 cubic yards of material and backfill have been excavated.
- 131 cubic yards of concrete have been poured to prepare for the installation of Roller Compacted Concrete to strengthen the dam.
- Installed temporary, 36-inch outlet piping to facilitate releases of water from the reservoir during construction.
- Currently commissioning the Roller Compacted Concrete (RCC) batch plant. It will produce RCC onsite to support strengthening of the dam.
- Installed a water quality monitoring system upstream and downstream of the worksite to ensure water quality is maintained.