Escondido, CA
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Yes, the fishing is great, but Lake Wohlford’s real value is key part of local water system


The view from behind Lake Wohlford. Photos by Jeff Epp

Introduction

Sometimes the best way to preserve history is to build something new.  The replacement of Lake Wohlford dam may be an “expensive dam project” but the value of the Lake’s water supply will preserve this meaningful investment for many more years.   With a need to improve the current dam at Lake Wohlford, the City of Escondido has done the math, compared alternatives, and determined that constructing a new dam immediately below the current dam will is actually safer, more efficient, and more economical in the long run.  

A Complete Local Water System

Many residents of the Escondido and Valley Center area know Lake Wohlford primarily for the fishing.  And indeed, fishing is great.  A 19 pound 3 ounce Largemouth bass was caught in 1986 and remains in the world’s “top 20” to this day.  Other monsters caught in the Lake include a 3 ½ pound Crappie in 2016, a 63.6 pound Blue Catfish  this year and a 16.95 pound Rainbow Trout in 2013.  

The Lake is also known for its scenic beauty.  Nestled in a pleasant valley below the historic Rancho Guejito, Lake Wohlford is a regional recreational amenity offering fishing areas, trails, and opportunities for active and passive recreation.  The Lake is home to other wildlife including Bald Eagles that nest and fledge their young, and many other species of raptors and migratory birds. There is boat access to the reservoir based around a marina facility on the north, a public park with picnic facilities and a ranger station, as well as the reservoir’s main parking areas.  Hiking trails surround the area, which is also adjacent to Bottle Peak, providing panoramic views of the entire inland valley.  

But while the Lake is pleasing to the eye and great for fishing, it is a key part of a complete local water system.  The first drops fall into the basin surrounding Lake Henshaw just outside the windows of the Henshaw Café, a local eatery and popular stopping point at the base of Palomar Mountain.  A vast groundwater basin lies underneath from which water is pumped into Lake Henshaw, controlled by the Henshaw Dam, then flows down the San Luis Rey River through the popular campground and recreation area owned by the La Jolla Band of Mission Indians.  

The next stop is a diversion structure which can either allow water to pass down the river through the Rincon, Pauma and Pala reservations, and ultimately into the Pacific Ocean.  However, most of the water is diverted into the Escondido Canal, a 14 mile concrete channel constructed in the 1890’s.  The Canal winds its way through the Rincon Reservation on the hillside to the east of Harrah’s, siphons across Hellhole Canyon, through the San Pasqual Reservation and into Lake Wohlford.  

Even then, the journey is not complete.  Leaving Lake Wohlford, water flows in pipes under the road, dropping sharply 495 feet into the Bear Valley Power plant.  After generating clean, energy, a siphon takes it under the busy Valley Center road below, up the other side, and into the Lake Dixon.  Mixed with imported water, the local water is then treated at the Escondido-Vista Water Treatment Plant and flows to Escondido faucets and through a flume to others in the Vista Irrigation District . . . with rarely a thought about the journey.  

Most southern California cities import all of their water from places as far away as Wyoming, Colorado, and Utah. The City of Escondido, the Vista Irrigation District, and the five local Bands of Indians have taken advantage of unique geography and thoughtful ancestors to preserve and save almost 16,000 acre feet of water from this area, which is then used to match another 16,000 acre feet via the federal government, conserved from lining canals in the Imperial Valley.  For all of the number geeks, the local portion is 5.2 billion gallons of water, which serves the needs of 40,000 homes.  But wait, there is more: The local water also provides a  valuable local supply in times of shortage or emergency if water cannot be imported from elsewhere.

A Rich Dam History

Engineering marvels aside, the Lake Wohlford Dam is part of a rich history surrounding the Escondido community.  Only because of the canal and dam was the city able to grow and thrive, especially with agriculture.  There was no imported water, and wells in the area were simply not sufficient to meet the needs of the early settlers and farmers who came to the Hidden Valley. 

Initial attempts to develop a local system started 140 years ago with early failed efforts—not due to engineering or design, but to politics and financing.  It wasn’t until the early 1890’s that permits were obtained, bond issues passed, contracts awarded allowing the original canal and dam to be constructed.  The original construction was of rock and dirt. Originally called “Bear Valley Dam” it was the first rockfill dam constructed in California for irrigation storage. The construction cost for both the dam and the land site was $110,000.  As originally constructed, the dam had a capacity of a little over 2,850 acre feet.

In July of 1895 the first water was released from the lake.  Originally known as the Bear Valley Reservoir, the Board of the Escondido Mutual Water Company (which later merged with the City of Escondido) voted on August 18, 1924 to change the name to “Lake Wohlford” in honor of Alvin Webster (A.W.) Wohlford.  A.W. Wohlford was a local farmer and owner of the Bank of Escondido. Originally from Nebraska, he had moved to the area and served on the Mutual Board of Directors starting the same year the dam was constructed.  He was the first of the Wohlford family to be key players in the Escondido community and the development of the local water supply.  

In 1924, the City enlarged the original dam using a hydraulic fill process, which is dirt pumped from the reservoir bottom through a pipe and placed on the upstream side of the existing rockfill dam. The enlargement of the dam increased the dam’s height to 100 feet and expanded Lake Wohlford’s storage capacity to 6,900 acre feet to serve the City’s growing population.  

Work has started on the Lake Wohlford Dam replacement, which is projected to cost about $68 million. Work should be completed by 2025. Photos by Jeff Epp

A Long And Winding Road through the Dam Bureaucracy

Nearly a decade and a half ago, in 2007, one of many routine seismic evaluations was conducted by the California Division of Safety of Dams (“DSOD”).  For the first time, engineers determined that the upper hydro fill section of the dam, added in 1924,  had the potential to liquefy and fail in the event of an earthquake with magnitude greater than 7.5.

The City reacted immediately to address this issue by simply lowering the water level of Lake Wohlford, so the maximum level of the lake does not exceed the level of the original, seismically-sound rock structure.  While this immediate solution completely addressed all of the safety issues, it was not a good long term solution because it did not take full advantage of either the storage or recreation opportunities available at the lake.

Over the next few years, the city evaluated alternatives, and in 2012, the Escondido City Council authorized a $3.4 million contract for design and environmental services for the Lake Wohlford Dam Replacement Project.  Although the contract was executed in 2012, the ensuring nine years have seen four significant amendments increasing the cost of this work more than a million and a half dollars.  

As one might imagine, building a dam requires multiple approvals from local governments and from federal, state, and local regulatory agencies.  A draft environmental report was first circulated in October of 2016  but it was not until 2020 that the Escondido City Council was finally able to approve the final report.  

Other regulatory activities include submitting a Notice of Intent to the State Water Resources Control Board for coverage by the general National Pollutant Discharge Elimination System permit for construction.  Because the new dam would occur within designated “waters of the U.S.” and would affect a jurisdictional stream, Escondido Creek, additional permits are required  under the California Fish and Game Code and the Federal Clean Water Act (“CWA”).  

From an engineering perspective, approval of the design and construction is also required by the California Department of Safety of Dams and the Federal Energy Regulatory Commission.   County permits and approvals were required for the Oakvale Road realignment work within County right-of-way.  And if everything goes roughly according to plan, the new dam will be completed in 2025.

The New Dam

Although studies began in earnest in 2012, it was not until 2017 that a final design was completed, based upon work by teams of consultants and regulatory agencies.  A design for a new, replacement dam to be constructed just downstream of the existing dam was completed in 2017.  

There are three core parts to the new dam: the foundation, the dam itself, and the spillway, settling basin and outlet tower.  The foundation will consist of material from the downstream canyon floor and rocky slopes to create a foundation on solid bedrock. About half of the excavated material will be re-usable in the new foundation.  A double-row grout curtain would be installed in the foundation to strengthen the foundation and reduce seepage.

The new dam will be constructed just downstream of the existing dam, about 125 feet above the foundation grade, with an elevation of 1,490 feet above sea level, with a width of about 650 feet. Both pedestrian and vehicle access will be constructed across the dam, but for maintenance purposes only. 

The actual construction starts with a “double walled grout curtain” which is not a type of window covering but an epoxy-like material injected into the area surrounding the dam foundation. Next comes “roller-compacted concrete” which is the same technique used in constructing the nearby Olivenhain Dam above Lake Hodges. With this method, conventional concrete (a mixture of cement, coarse aggregate, sand and water) is still used, but the amount of water is minimized.  This allows the material to be placed using conveyers, dump trucks, dozers, and roller compactors rather than a large, wet concrete pour used in older dams, such as the Hoover Dam.  The mix is dry enough to prevent equipment from sinking but wet enough to allow it to be firmly and evenly distributed.  Starting with 12 inch layers at the base of the dam, about 100,000 cubic feet of this material will form the new Lake Wohlford Dam.   

The third component is the additional outlet tower, spillway and settling basin.  The outlet tower is simply a structure which sticks out of the Lake just above the dam.  The outlet tower connects to the dam’s downstream emergency release valve and works with the settling basin to handle discharges into Escondido Creek, either very rapidly for safety issues, or more slowly drain the reservoir without eroding or washing out the creek.  

As the name implies, the spillway works in overflow situations, such as a maximum winter storm.   The Lake Wohlford spillway would be constructed in the center of the dam and be built of traditional of cast-in-place concrete.  

Finally, an expensive but important part of the new dam project involves re-aligning Oakvale Road, which skirts a steep rock face just southwest of the existing left abutment of the existing dam and conflicts with the proposed location for the replacement dam’s left abutment. Construction has already started on this part of the project and will realign and straighten about 1,200 feet of the road.  However, the new road portion will include two 12-foot lanes in each direction, a 10-foot lane for non-motorized traffic on the northern shoulder, and drainage improvements.  

The road leading to the Lake Wohlford dam replacement construction.
Photos by Jeff Epp

Paying for Construction

Ratepayers should be quite pleased with the City’s Deputy City Manager and Director of Utilities, Chris Mckinney.  While he has spent more than a few nights lying awake over the project, the package assembled to pay for the new dam, and adopted by the City Council is protective of the ratepayers.  

The cost of construction of the dam as designed is projected to be $68 million dollars, with proposed environmental mitigation projected to cost about $3.5 million.  Here’s the great news: impacts to ratepayers are already included in current water rates.  Low interest funding comes from the federal government through the Water Infrastructure Finance and Innovation Act.  The State of California awarded the city a $15 million California Proposition 1E Grant and Assemblymember Marie Waldron just completed efforts to successfully enact legislation extending the term of this funding.  

New Capacity and Opportunities

The replacement dam will not make any changes to Lake Wohlford’s historic high water level or storage capacity, thus retaining the original historic vision. Before the mandatory drawdown in 2007, the average elevation of Lake Wohlford was 1,462.2 feet, with a storage capacity of approximately 6,200 acre feet.  

The substantial benefits of the project not only include restoring water levels to historic elevations, which would be beneficial to groundwater supply and recharge rates but permanently solving any potential seismic or safety related issues with modern construction methods and materials.  In turn, the life expectancy of the dam will stretch out at least another century, providing years and years more of local water availability, storage, and clean power generation. 

And of course, great fishing.  

Jeff Epp is the former city attorney and city manager of Escondido. He worked for a total of 36 years for the city, and is intimately knowledgeable about the history of Lake Wohlford and its dam.

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