Inland Feeder
Encyclopedia
The Inland Feeder is a 44 mi (70.8 km) high capacity water conveyance system that connects the California State Water Project
to the Colorado River Aqueduct
and Diamond Valley Lake
. The Metropolitan Water District of Southern California
designed the system to increase Southern California
's water supply reliability in the face of future weather pattern uncertainties, while minimizing the impact on the San Francisco Bay
/Sacramento-San Joaquin Delta environment in Northern California. The feeder takes advantage of large volumes of water when available from Northern California, depositing it in surface storage reservoirs, such as Diamond Valley Lake, and local groundwater basins for use during dry periods and emergencies. This improves the quality of Southern California drinking water by allowing more uniform blending of better quality water from the state project with Colorado River
supplies, which has a higher mineral content.
The feeder system includes three large tunnels, two running through the San Bernardino Mountains
and one running under the Riverside Badlands between Redlands and Moreno Valley. Construction began in 1997 and water began flowing through the system in mid-2010. It is currently the primary source of water for Diamond Valley Lake.
, where water is received from Silverwood Lake, and makes its way through the Arrowhead West and Arrowhead East tunnels into Highland. From there the Highland pipeline and Mentone pipeline carry water to Redlands and the northern end of the Riverside Badlands Tunnel. The Riverside Badlands Tunnel runs south into Moreno Valley where a series of pipelines carries and deposits water into Diamond Valley Lake
near Hemet.
and Tactical to Practical
on the History Channel, and Discovery Channel
’s Build It Bigger. Because of the challenges faced during construction of the tunnels, the project received the 2010 E3 Environmental Sustainability Honor Award by the American Academy of Environmental Engineers
.
The west tunnel was the most difficult of the three tunnels to excavate. It was excavated using a tunnel boring machine
(TBM) that took over four years to bore its way through the mountain. The TBM was launched from the Waterman Portal and tunneled in a westerly, uphill direction toward the Devil Canyon portal at a slight uphill gradient of approximately 2 inches per 100 linear feet. Crews faced many challenges during the excavation including the 2003 Old Fire
which destroyed construction equipment at the Waterman Portal and halted tunneling for ten days. Later that year, a flash flood engulfed the Waterman Portal site and submerged the TBM. It took four months to restore operations in the aftermath of the flooding.
The TBM faced many challenges during the tunneling. Much of the tunneling took place in water-bearing strata
of metamorphic and granitic rock. The presence of water, coupled with the depth of the tunnel, up to 1,100 feet underground, forced the tunneling team to deal with water pressures in excess of 150 pounds per square inch. Additionally, the tunnel alignment crossed or traversed near several significant faults and shear zones, including branches of the San Andreas
and Arrowhead Springs Faults. In these faulted areas, the massive blocks of rock were broken into fine debris that were treated with grout before tunneling could safely cross through these zones. A particularly challenging reach of the tunnel alignment was encountered in the last 1,500 feet of the tunneling work as the TBM crossed five significant fault and shear zones along the tunnel alignment on its way to completion at the Devil Canyon Portal. While tunneling in this zone in mid-2008, the TBM began dipping as it encountered a 40-foot-wide fault zone of completely crushed, weak rock. Concrete and steel foundation pads were constructed in front of the cutterhead to stabilize the TBM and correct the alignment of the machine as it crossed the weak ground within the fault zone. The tunnel was completed in August 2008 with installation of pipeline being completed in 2009.
The tunnel was constructed in two segments. Original construction commenced in early 1997 at the City Creek Portal, and mining progressed along an uphill gradient from east to west. After two years of mining effort, and more than 8,000 feet into the tunnel alignment, groundwater flows into the excavated tunnel began to steadily increase. Following extensive consultation with the U.S. Forest Service, MWD decided to halt mining on the east tunnel and install the final 12-foot diameter pipe liner in the excavated portion of the tunnel. MWD and the U.S. Forest Service worked to determine how best to complete the remaining 22,458 feet of the tunnel. This collaboration resulted in significant revisions to the original design, revisions that would ultimately allow the tunneling effort to meet the strict groundwater inflow requirements of the U.S. Forest Service Special Use Permit. The tunnel was redesigned to use bolted and gasketed precast concrete tunnel segments. Not only were these segments designed to provide structural support to the mined tunnel, but they also were capable of delivering a nearly watertight environment inside the tunnel to dramatically limit the amount of groundwater inflow during the mining operations. Construction resumed from the Strawberry portal working towards the original City Creek Portal construction.
The tunnel was constructed using a TBM, originating from the Strawberry Portal and mining at a slight downhill gradient of approximately 18 feet per 100 linear feet. Much like the West Tunnel, the TBM in the east tunnel encountered water-bearing strata of metamorphic and granitic rock. The presence of water, coupled with the depth of the tunnel below the surface, up to 2,100 feet underground, forced the tunneling team to deal with water pressures in the tunnel heading in excess of 200 pounds per square inch. Also much like the West tunnel mining efforts, the TBM had to traverse branches of the San Andreas fault, and on one occasion in late 2006, the TBM became stuck as mining efforts approached some particularly difficult ground. Hand-mining efforts above the TBM shield were eventually employed to free the stuck machine. The tunnel was completed in May 2008 with the installation of pipeline being completed in 2009.
Construction of the tunnel began in October 1998 with the excavation of the Gilman Portal and dewatering work at the two intermediate shafts. Tunnel excavation was carried out from November 1999 through July 2001 using a shielded TBM. Construction of the tunnel included many challenges. The TBM had to bore its way through diverse ground conditions consisting of weak sedimentary rocks; strong, fractured metamorphic rocks; and alluvium
, all of which were below the groundwater table. Special measures such as probing and grouting ahead of the TBM and, in particular, deep dewatering wells, were demonstrated to be effective for controlling adverse ground conditions. The project also showed the advantage of working from a portal. The Gilman Portal site proved to be ideal, supporting very efficient mining and muck disposal operations and also allowing long pipe sections to be installed in the tunnel, significantly reducing the amount of field welding required.
California State Water Project
The California State Water Project, commonly known as the SWP , is the world's largest publicly built and operated water and power development and conveyance system. The SWP was designed and is operated by the California Department of Water Resources...
to the Colorado River Aqueduct
Colorado River Aqueduct
The Colorado River Aqueduct, or CRA, is a water conveyance in Southern California in the United States, operated by the Metropolitan Water District of Southern California . The aqueduct impounds water from the Colorado River at Lake Havasu on the California-Arizona border west across the Mojave...
and Diamond Valley Lake
Diamond Valley Lake
The embankment required of crushed rock. An on-site crushing plant crushed and processed over 14 million tons of rock in 20 months to supply the dam's materials. The cut-off wall, which consists of a thick plastic concrete mix constructed through the weathered portion of bedrock, varies in depth...
. The Metropolitan Water District of Southern California
Metropolitan Water District of Southern California
The Metropolitan Water District of Southern California is the largest supplier of treated water in the US. The name is usually shortened to the "Metropolitan Water District" or simply "MWD". It is a cooperative of 14 cities and 12 municipal water districts that indirectly provides water to 18...
designed the system to increase Southern California
Southern California
Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...
's water supply reliability in the face of future weather pattern uncertainties, while minimizing the impact on the San Francisco Bay
San Francisco Bay
San Francisco Bay is a shallow, productive estuary through which water draining from approximately forty percent of California, flowing in the Sacramento and San Joaquin rivers from the Sierra Nevada mountains, enters the Pacific Ocean...
/Sacramento-San Joaquin Delta environment in Northern California. The feeder takes advantage of large volumes of water when available from Northern California, depositing it in surface storage reservoirs, such as Diamond Valley Lake, and local groundwater basins for use during dry periods and emergencies. This improves the quality of Southern California drinking water by allowing more uniform blending of better quality water from the state project with Colorado River
Colorado River
The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...
supplies, which has a higher mineral content.
The feeder system includes three large tunnels, two running through the San Bernardino Mountains
San Bernardino Mountains
The San Bernardino Mountains are a short transverse mountain range north and east of San Bernardino in Southern California in the United States. The mountains run for approximately 60 miles east-west on the southern edge of the Mojave Desert in southwestern San Bernardino County, north of the...
and one running under the Riverside Badlands between Redlands and Moreno Valley. Construction began in 1997 and water began flowing through the system in mid-2010. It is currently the primary source of water for Diamond Valley Lake.
Geography
The feeder begins at the Devil Canyon afterbay in the foothills of San BernardinoSan Bernardino
San Bernardino, California is a large city in the Inland Empire Metropolitan Area of Southern California.San Bernardino may also refer to:-Landforms:*San Bernardino , a torrent that flows through the Italian province of Verbano-Cusio-Ossola...
, where water is received from Silverwood Lake, and makes its way through the Arrowhead West and Arrowhead East tunnels into Highland. From there the Highland pipeline and Mentone pipeline carry water to Redlands and the northern end of the Riverside Badlands Tunnel. The Riverside Badlands Tunnel runs south into Moreno Valley where a series of pipelines carries and deposits water into Diamond Valley Lake
Diamond Valley Lake
The embankment required of crushed rock. An on-site crushing plant crushed and processed over 14 million tons of rock in 20 months to supply the dam's materials. The cut-off wall, which consists of a thick plastic concrete mix constructed through the weathered portion of bedrock, varies in depth...
near Hemet.
Construction
Construction of the Inland Feeder began in 1997 with the excavation of the Riverside Badlands Tunnel followed by the excavation of the two Arrowhead tunnels. Water began flowing through the system in mid-2010. Construction of the tunnels was such a large project that it was featured in the television shows Modern MarvelsModern Marvels
Modern Marvels is a documentary television series that premiered on January 1, 1995 on History. The program focuses on how technologies affect and are used in today's society....
and Tactical to Practical
Tactical to Practical
Tactical to Practical was a short-lived History Channel program that ran from 2003 to 2005. Each episode documented ways in which technologies utilized by the civilian public were originally developed to serve military purposes. The show was hosted by Hunter Ellis....
on the History Channel, and Discovery Channel
Discovery Channel
Discovery Channel is an American satellite and cable specialty channel , founded by John Hendricks and distributed by Discovery Communications. It is a publicly traded company run by CEO David Zaslav...
’s Build It Bigger. Because of the challenges faced during construction of the tunnels, the project received the 2010 E3 Environmental Sustainability Honor Award by the American Academy of Environmental Engineers
American Academy of Environmental Engineers
The American Academy of Environmental Engineers is a society of professional engineers who have demonstrated special expertise in environmental engineering beyond that normally required for professional practice, in a process similar to what is required for medical and other professional specialty...
.
Arrowhead West Tunnel
The Arrowhead West Tunnel is 3.8 mi (6.1 km) long and 12 ft (3.7 m) in diameter. The tunnel begins at Devil's Canyon and is the first of the three tunnels in the feeder project. It continues east to the Waterman portal at Old Waterman Canyon Road and State Highway 18. The tunnel was constructed with a grade to allow water to flow by gravity; from the time the water enters the Devil Canyon Portal until it exits the Waterman Portal, the tunnel will have dropped about 31 feet in elevation.The west tunnel was the most difficult of the three tunnels to excavate. It was excavated using a tunnel boring machine
Tunnel boring machine
A tunnel boring machine also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They can bore through anything from hard rock to sand. Tunnel diameters can range from a metre to almost 16 metres to date...
(TBM) that took over four years to bore its way through the mountain. The TBM was launched from the Waterman Portal and tunneled in a westerly, uphill direction toward the Devil Canyon portal at a slight uphill gradient of approximately 2 inches per 100 linear feet. Crews faced many challenges during the excavation including the 2003 Old Fire
Old Fire
The Old Fire was a wildfire that started on October 25, 2003 in the San Bernardino Mountains, in San Bernardino County of southern California.It was one of over a dozen wildfires burning in Southern California wildlands at the same time...
which destroyed construction equipment at the Waterman Portal and halted tunneling for ten days. Later that year, a flash flood engulfed the Waterman Portal site and submerged the TBM. It took four months to restore operations in the aftermath of the flooding.
The TBM faced many challenges during the tunneling. Much of the tunneling took place in water-bearing strata
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
of metamorphic and granitic rock. The presence of water, coupled with the depth of the tunnel, up to 1,100 feet underground, forced the tunneling team to deal with water pressures in excess of 150 pounds per square inch. Additionally, the tunnel alignment crossed or traversed near several significant faults and shear zones, including branches of the San Andreas
San Andreas Fault
The San Andreas Fault is a continental strike-slip fault that runs a length of roughly through California in the United States. The fault's motion is right-lateral strike-slip...
and Arrowhead Springs Faults. In these faulted areas, the massive blocks of rock were broken into fine debris that were treated with grout before tunneling could safely cross through these zones. A particularly challenging reach of the tunnel alignment was encountered in the last 1,500 feet of the tunneling work as the TBM crossed five significant fault and shear zones along the tunnel alignment on its way to completion at the Devil Canyon Portal. While tunneling in this zone in mid-2008, the TBM began dipping as it encountered a 40-foot-wide fault zone of completely crushed, weak rock. Concrete and steel foundation pads were constructed in front of the cutterhead to stabilize the TBM and correct the alignment of the machine as it crossed the weak ground within the fault zone. The tunnel was completed in August 2008 with installation of pipeline being completed in 2009.
Arrowhead East Tunnel
The Arrowhead East Tunnel is 5.8 mi (9.3 km) long and 12 ft (3.7 m) in diameter and runs under McKinley Mountain. It begins at the Strawberry Portal in Strawberry Canyon near State Highway 18 and continues east to the City Creek Portal near State Highway 330. The East tunnel was also constructed at a slight downhill grade to allow water to flow by gravity; from the time the water enters the Strawberry Portal until it exits the City Creek Portal, the tunnel will have dropped about 55 feet in elevation.The tunnel was constructed in two segments. Original construction commenced in early 1997 at the City Creek Portal, and mining progressed along an uphill gradient from east to west. After two years of mining effort, and more than 8,000 feet into the tunnel alignment, groundwater flows into the excavated tunnel began to steadily increase. Following extensive consultation with the U.S. Forest Service, MWD decided to halt mining on the east tunnel and install the final 12-foot diameter pipe liner in the excavated portion of the tunnel. MWD and the U.S. Forest Service worked to determine how best to complete the remaining 22,458 feet of the tunnel. This collaboration resulted in significant revisions to the original design, revisions that would ultimately allow the tunneling effort to meet the strict groundwater inflow requirements of the U.S. Forest Service Special Use Permit. The tunnel was redesigned to use bolted and gasketed precast concrete tunnel segments. Not only were these segments designed to provide structural support to the mined tunnel, but they also were capable of delivering a nearly watertight environment inside the tunnel to dramatically limit the amount of groundwater inflow during the mining operations. Construction resumed from the Strawberry portal working towards the original City Creek Portal construction.
The tunnel was constructed using a TBM, originating from the Strawberry Portal and mining at a slight downhill gradient of approximately 18 feet per 100 linear feet. Much like the West Tunnel, the TBM in the east tunnel encountered water-bearing strata of metamorphic and granitic rock. The presence of water, coupled with the depth of the tunnel below the surface, up to 2,100 feet underground, forced the tunneling team to deal with water pressures in the tunnel heading in excess of 200 pounds per square inch. Also much like the West tunnel mining efforts, the TBM had to traverse branches of the San Andreas fault, and on one occasion in late 2006, the TBM became stuck as mining efforts approached some particularly difficult ground. Hand-mining efforts above the TBM shield were eventually employed to free the stuck machine. The tunnel was completed in May 2008 with the installation of pipeline being completed in 2009.
Riverside Badlands Tunnel
The $119 million Riverside Badlands Tunnel is 8 mi (12.9 km) long, the longest tunnel in the feeder project, with a diameter of 12 ft (3.7 m) and runs from Redlands, underneath the Crafton Hills and San Timoteo Badlands through to Moreno Valley. The tunnel ranges in depth from 50 to 850 feet and contains 1500 feet (457.2 m) of pipeline. It has two primary portals; the Gilman portal in Moreno Valley and the Opal portal in Redlands, each with permanent concrete structures. Along with the two portals are two access-ventilation shafts: one along San Timoteo Canyon road and another along Live Oak Canyon road. The tunnel was finished in 2003, a year ahead of schedule.Construction of the tunnel began in October 1998 with the excavation of the Gilman Portal and dewatering work at the two intermediate shafts. Tunnel excavation was carried out from November 1999 through July 2001 using a shielded TBM. Construction of the tunnel included many challenges. The TBM had to bore its way through diverse ground conditions consisting of weak sedimentary rocks; strong, fractured metamorphic rocks; and alluvium
Alluvium
Alluvium is loose, unconsolidated soil or sediments, eroded, deposited, and reshaped by water in some form in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel...
, all of which were below the groundwater table. Special measures such as probing and grouting ahead of the TBM and, in particular, deep dewatering wells, were demonstrated to be effective for controlling adverse ground conditions. The project also showed the advantage of working from a portal. The Gilman Portal site proved to be ideal, supporting very efficient mining and muck disposal operations and also allowing long pipe sections to be installed in the tunnel, significantly reducing the amount of field welding required.