Lake Hodges Projects

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About This Project

 

 

The Lake Hodges Projects are part of the San Diego County Water Authority's Emergency Storage Project, a system of reservoirs, interconnected pipelines and pumping stations designed to make water available to the San Diego region in the event of an interruption in imported water deliveries.

The Lake Hodges Projects connect the city of San Diego’s Hodges Reservoir, also called Lake Hodges, to the Water Authority’s Olivenhain Reservoir. The connection provides the ability to store 20,000 acre-feet of water in Hodges Reservoir for emergency use. The connection also allows water to be pumped back and forth between Hodges Reservoir and Olivenhain Reservoir. From Olivenhain Reservoir, water can be distributed throughout the region by the Water Authority’s delivery system.

When water is transferred downhill from Olivenhain Reservoir into Hodges Reservoir, it generates up to 40-megawatts of peak hydroelectric energy, enough power to annually sustain nearly 26,000 homes. This energy helps offset project operating costs and support future Water Authority projects. The Lake Hodges Projects will also help keep Hodges Reservoir at a more constant level during dry seasons, capture runoff during rainy seasons and prevent spills over Hodges Dam.

ABOUT THIS PROJECT - DETAILS
 

Project Components

The Lake Hodges Projects has four components:  

  1. Pipeline Tunnel
    It is a 10-foot diameter underground pipeline, contained in a 1.25 mile long tunnel, and connects the two reservoirs.
     
  2. Pump Station
    It moves water back and forth between the two reservoirs and generates electricity.
     
  3. Electrical Switchyard 
    It provides electricity to the pump station and sends electricity from the pump station to a local transmission system.
     
  4. Inlet-outlet Structure
    It is located below the water surface in Hodges Reservoir. It draws and discharges water between the Hodges Reservoir and the pump station.

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SCHEDULE
 
 

Construction began in 2005 and was completed in 2012.

 

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MAP
 
 
Lake Hodges Projects
 

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MULTIMEDIA
 
 
Photos
To view a diagram of the Lake Hodges Projects components, click on the "Map" section above. 
 

Pipeline Tunnel

Completed in spring 2007, the pipeline tunnel is 1.25 miles-long and contains a 10-foot diameter steel pipeline that rises 770 feet in elevation from Hodges Reservoir to Olivenhain Reservoir.
 

Water will flow back and forth between Hodges and Olivenhain Reservoirs within this 10-foot diameter steel pipe. The pipe’s epoxy coat protects the steel pipe from internal corrosion. In total, 148 sections of pipe were used.
 

This is a “pipe carrier” was used to lift and place the steel pipe within the 1.25-mile-long pipeline tunnel.
 

A mucking machine pushes the pipe carrier into the pipeline tunnel.
 

In this image, the pipe section is placed within the pipeline tunnel and attached to another installed section of pipe.
 

The pipe section is secured inside the pipeline tunnel using timber bracing. The bracing keeps the pipe from moving and allows the area between the outside of the pipe and the tunnel wall to be backfilled with grout.
 

One by one, each section of pipe was welded together and formed the pipeline inside the tunnel.
  

After each pipe segment is welded together, the space between the 12-foot diameter tunnel and the 10-foot diameter pipeline was filled with grout.
Grout is a fluid material injected into soil, rock, concrete, or other construction material. Once hardened, it forms a permanent impervious, watertight bond that provides structural strength to the pipeline tunnel. This picture shows the grout being pumped through a grout port installed in the pipe.
 

Construction crews inspect the inside of the pipeline tunnel prior to completion in spring 2007.

Once completed, the pipeline tunnel was sealed in May 2007. The seal was removed when the pump station contractor connected the pump station to the pipeline.
 
 
 

Pump Station

The Hodges Pump Station extends 12 stories underground and houses two 28,000 horsepower pump turbines that will generate 40 megawatts of electricity as water flows down the pipeline tunnel from Olivenhain Reservoir to Hodges Reservoir. Electricity generated by the pump turbines is transmitted to an outdoor switchyard, then to a 69kV, 1/4-mile-long power line that connects to the existing local transmission system.
 
 

Construction equipment and materials used to excavate the pit that houses the below-ground pump station were lowered and lifted in and out using a crane.
 
 

Looking down from the top pump station pit, you can see the excavators removing material that was blasted. The material was put in a dumpster-sized bucket and hauled out of the pit using a crane.
 
 

At the bottom of the pit that now houses the pump station, construction workers drilled pilot holes horizontally towards Lake Hodges. This construction method is referred to as a drill & blast method, in which pilot holes are drilled for explosive charges. Once the explosive charges are set off, the resulting debris is carried out and the process is repeated.
  
 

The two-pronged inlet/outlet tunnel will draw or discharge water back and forth from the inlet/outlet structure, located at the bottom of Hodges Reservoir, and the pump station.
 

After construction crews completed excavation of the 12-story Hodges Pump Station pit in June 2007, construction of the pump station’s foundations, walls, and floors started. Here, a construction worker places steel reinforcing bars within the Pump Station floor. The reinforcing bars were encased within concrete to strengthen and hold the concrete together.

Construction crews started pouring the foundation of the pump station in June 2007. Here, concrete is lowered in a large bucket and poured onto the steel framework.
 
 

Another method of delivering concrete form the top of the pump station excavation to lower sections was the use of a concrete pump truck.
 
 
 

As concrete is poured, a construction worker levels the concrete with an extension trowel.
 
 

Here workers smooth and level a floor within the pump station.
 
 

As construction continued within the pump station, steel-reinforced walls were poured.
 

Steel-reinforced concrete walls within the pump station reached ground level in April 2008.
 
 

As concrete work on floors and walls took place, some of the water pipes and equipment was installed. This image captures the installation of equipment that now houses the two pump turbines. The pump turbines will generate electricity as water flows from Olivenhain into Hodges Reservoir. The pump turbines will also send water from Hodges Reservoir uphill 1.25 miles to Olivenhain Reservoir.
 

Equipment for the Lake Hodges Projects came from all over the world. This 98-ton section of pipe is 21 feet in length and width and arrived to the site in May 2009. The Y-shaped bifurcated pipe now connects the pump station to the 1.25 mile-long pipeline between the Hodges and Olivenhain reservoirs and splits the tunnel’s water flow that feeds two pump turbines housed in the pump station.
 
  
 

This long section of pipe is part of a connecting series of pipes that link the Y-shaped bifurcated pipe that enters the pump station with the pipeline that connects to the Olivenhain Reservoir. The wood inside reinforces the pipe, keeping the pipe round, and is removed once the pipeline exterior is encased in concrete.
 
 

This section of pipe connects to the 10-foot diameter pipeline already encased in the 1.25 mile long tunnel that connects to the Olivenhain Reservoir.
 
 

An aerial view of the facility as construction neared completion. The two four-foot diameter penstock pipes exiting the left side meet at the Y-shaped pipe and then form one pipe going under a construction access road visible at the far left of the photo.
 

This 48-inch diameter pipe inside the pump station connects to one of the two 28,000 horsepower pump turbines. The pipe will be completely enclosed by the pump station when work is completed.
  

Workers are preparing to pour concrete to secure the two pump turbines inside the pump station.
 

Workers created wood forms to prepare for pouring concrete to erect a concrete encasement around a 200-foot section of pipe. The pipe connects the pump station to the 1.25 mile tunnel originating at Olivenhain Reservoir. The encasement and pipe are now located under 25 feet of soil.
  

Two 28,000 horsepower pump turbines will move the water in and out of the pump station. Each pump turbine can generate up to 40 Megawatts of energy, enough for 26,000 homes. This photo shows the top of one turbine in place inside the pump station. A centering device used during installation is visible on the top of the head cover.
 
  

In April 2009, community members from the Lake Hodges surrounding communities viewed sample varnish colors on the concrete walls of the pump station. Their preferred color choice was applied to the pump station's walls that extend 9 feet above ground to help blend it in with the natural surroundings. The pump station also extends 10 stories below ground.
 
  

A small jib crane will remain on the roof of the pump station. It will be used to lower heavy equipment in and out of the pump station for repairs or maintenance. The crane was painted brown at the recommendation of the Lake Hodges Community Landscape Committee.
   

Electrical Switchyard - Power line and Substation

The electrical switchyard provides electricity to the pump station and sends electricity from the pump station to a local transmission system. As water flows downhill from the Olivenhain Reservoir, it generates up to 40 megawatts of peak hydroelectric energy, enough power to annually sustain nearly 26,000 homes. This energy helps offset project operating costs and supports future Water Authority projects. 
 
 

Electricity generated by the pump turbines will be transmitted to an outdoor switchyard. San Diego Gas & Electric’s construction crews started work on the switchyard in June 2007.
 
 

This 69kV, quarter-mile-long power line connects the electrical switchyard to the existing San Diego Gas & Electric local transmission system.
 

The San Diego Gas & Electric substation was completed in February 2008. Shortly afterwards, the Water Authority constructed electrical facilities adjacent to the substation.
 

Taken in 2008, this picture shows an overall view of the construction site with the electrical substation seen in the left foreground.
 

Inlet/Outlet Structure

The Hodges Inlet/Outlet Structure is located below the surface of Hodges Reservoir. The structure is connected to the pump station by a 200-foot-long tunnel. The pump station draws or discharges water from the reservoir through the inlet-outlet structure. A trash rack, located at at the west end of the structure, prevents large debris from entering the pump station. At the east end of the pump station, water travels through a 10-foot diameter underground pipeline to the Olivenhain Reservoir, 1.25 miles away.
 
 

A cofferdam was constructed around the work site in Hodges Reservoir. The cofferdam is a temporary enclosure from which water is pumped to create a dry area to allow construction of the inlet/outlet tunnel and structure.
 

The inlet/outlet structure was constructed within the walls of the cofferdam. Crews excavated material until they reached the lake bottom.

The cofferdam walls were reinforced with shotcrete and rock bolts, which supported the excavation of the inlet/outlet structure.

Pumps inside the cofferdam cells in the dam structure kept the area dry so that workers could install the inlet-outlet structure and tailrace tunnel.

The cofferdam was completely installed by March 2007. Dismantling began in April 2009. The horse-shoe shaped structure held back the reservoir water while the contractor built the inlet-outlet structure and its connecting tunnel on the lake floor. (photo February 2009)

Two large cranes were brought on to the site to dismantle the cofferdam. As the cofferdam was dismantled, the components were removed from the site and hauled to a metal scrap yard for recycling. The small rocks that had been inside each cell were removed by an excavator and then used as backfill around the pump station walls.
 

Before the contractor could begin dismantling the cofferdam, the entire area had to be flooded so that the water level inside the cofferdam could be the same as the reservoir water level.
 

The cofferdam was made of 13 connecting cells of steel sheets and pilings. A crane lifts up one of the pilings from a cell. The pilings extended 5 to 15 feet below the reservoir bottom, depending on their location. At the shoreline, the exposed portion was about 55 feet high.
 

A crane lowered a circular template into the center of each cofferdam cell to stabilize it. Then each of the cell’s steel sheets could be removed and the pilings were pulled out from the reservoir bottom.

The template is lowered into place and secured.

During construction for the inlet-outlet structure and related equipment, a string of buoys helped keep boaters from the cofferdam. Connected to the string of buoys was a mesh-like underwater net called a silt curtain, which reduced the amount of underwater dirt that could flow out into the reservoir.

Once the cofferdam was completely removed in September 2009, the shoreline was stabilized with riprap made of large rocks. A new buoy system was installed (visible red line) to protect the submerged inlet-outlet structure from boaters.
 

Construction of the facility is nearing completion.  Trailers were installed around the pump station to support the final build and commissioning activities.  These were removed when the facility was fully tested and placed in commercial operation.
 
 

 

 

 

 
Videos (None available)
 
 
Other (None available)
 

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PUBLICATIONS
 
 
Newsletters:
icon_pdf.pngCommunity Letter (April 21, 2010) 
icon_pdf.pngCommunity Letter (February 12, 2010)
icon_pdf.pngCommunity Letter (November 24, 2009)
icon_pdf.pngCommunity Letter (June 10, 2009)
icon_pdf.pngGoing Green Announcement (March 23, 2009)
icon_pdf.pngElectronic Notification Postcard (February 10, 2009)
icon_pdf.pngCommunity Letter (December 4, 2008)
icon_pdf.pngCommunity Letter (September 15, 2008)
icon_pdf.pngCommunity Letter (July 25, 2008)
icon_pdf.pngCommunity Advisory (May 16, 2008)

 icon_pdf.pngCommunity Letter (May 9, 2008)
icon_pdf.pngCommunity Letter (April 11, 2008)
icon_pdf.pngCommunity Letter (January 11, 2008)
icon_pdf.pngCommunity Letter (October 12, 2007)
icon_pdf.pngCommunity  Letter (June 22, 2007)
icon_pdf.pngLake Hodges Hills Community Introduction Letter (June 20, 2007)
icon_pdf.pngCommunity Letter (May 11, 2007)
icon_pdf.pngCommunity Letter (April 27, 2007)
 icon_pdf.pngCommunity Letter (January 19, 2007)
icon_pdf.pngCommunity Letter (December 11, 2006)
icon_pdf.pngCommunity Letter (July 31, 2006)
icon_pdf.pngCommunity Letter (April 26, 2006)
icon_pdf.pngCommunity Letter (March 27, 2006)
icon_pdf.pngCommunity Letter (January 26, 2006)
icon_pdf.pngCommunity Letter (January 6, 2006)
icon_pdf.pngCommunity Letter (November 4, 2005)
icon_pdf.pngCommunity Letter (September 9, 2005)
icon_pdf.pngCommunity Letter (July 7, 2005)
icon_pdf.pngCommunity Letter (May 26, 2005)
icon_pdf.pngCommunity Letter (March 25, 2005)
icon_pdf.pngProject Update (December 2004)
icon_pdf.pngCommunity Letter (December 14, 2004)
 

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COMMUNITY OUTREACH
 
Meeting Summaries:
icon_pdf.pngDel Dios Town Council (November 10, 2010)
icon_pdf.pngDel Dios Town Council (May 17, 2010)
icon_pdf.pngDel Dios Town Council (February 10, 2010)
icon_pdf.pngDel Dios Town Council (September 9, 2009)
icon_pdf.pngDel Dios Town Council (February 11, 2009)
icon_pdf.pngDel Dios Town Council (October 8, 2008)
icon_pdf.pngDel Dios Town Council (May 14, 2008)
icon_pdf.pngDel Dios Town Council (February 20, 2008)
icon_pdf.pngSan Dieguito Planning Group (January 31, 2008)
icon_pdf.pngDel Dios Town Council (January 16, 2008)
icon_pdf.pngDel Dios Town Council (June 13, 2007)
icon_pdf.pngDel Dios Town Council (January 10, 2007)
icon_pdf.pngDel Dios Town Council (September 13, 2006)
icon_pdf.pngDel Dios Town Council (May 10, 2006)
icon_pdf.pngDel Dios Town Council (February 8, 2006)
icon_pdf.pngDel Dios Town Council (October 12, 2005)
icon_pdf.pngDel Dios Town Council (July 13, 2005)
icon_pdf.pngDel Dios Town Council (June 8, 2005)
icon_pdf.pngDel Dios Town Council (March 9, 2005)
icon_pdf.pngDel Dios Town Council (November 10, 2004)
icon_pdf.pngDel Dios Town Council (July 14, 2004)
icon_pdf.pngLake Hodges Multi-Agency Update (April 28, 2004)
icon_pdf.pngDel Dios Town Council (March 10, 2004)
icon_pdf.pngDel Dios Town Council (November 12, 2003)
icon_pdf.pngDel Dios Town Council (June 11, 2003)
icon_pdf.pngDel Dios Town Council (February 12, 2003)
icon_pdf.pngDel Dios Town Council (October 9, 2002)

 

 

Lake Hodges Community Landscape Committee
The Water Authority formed the Lake Hodges Community Landscape Committee to provide community input to help design and develop the future landscaping of the Lake Hodges Projects. Landscaping will be limited to sections surrounding the Lake Hodges pump station building site, along the Coast to Crest Trail within the project site, and at the windsurfer parking lot just south of the pump station. The committee, comprised from community members from Del Dios, Lake Hodges Hills, Lake Hodges Native Plant Club, and the San Diego Windsurf Association, met with Water Authority staff from September 2007 through January 2008.

Meeting Summaries:
icon_pdf.pngLandscape Committee Meeting Summary (January 24, 2008)
icon_pdf.pngLandscape Committee Meeting Summary (September 27, 2007)
icon_pdf.pngLandscape Committee Meeting Summary (September 8, 2007)

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ENVIRONMENTAL DOCUMENTS
 

Click here to view the report and other environmental documents for this project.

 

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CONTACT INFORMATION
 

For more information about this project, please call toll free (877) 682-9283, ext. 7001 or email espinfo@sdcwa.org.

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