Category: Landslide Mitigation

Oroville Dam Engineering: What Happened?

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The California Department of Water Resources stopped the spillway flow on Thursday morning to allow engineers to evaluate the integrity of the structure after water had been released at 20,000 cubic feet per second through the night.

(Courtesy of the California Department of Water Resources).

Last week California’s Oroville Dam, the tallest dam in the United States, almost failed due to a surplus of water filling Lake Oroville. As the lake filled higher and higher, water was being released, via spillways, into the Feather River. The volume of water caused erosion of the dam’s main spillway, causing it to crater and break apart. As a result, the dam’s emergency spillway began to erode. That spillway had never been used and was unlined. The lack of concrete lining may have led to its erosion as well.

Nearly 200,000 people were evacuated from the area, many of them fleeing to higher ground cities like Sutter. As the water began to recede, residents began to travel back home.

But what went wrong? What caused the damage in the first place?… Continue Reading Oroville Dam Engineering: What Happened?

Avoiding Surface Water Drainage Issues

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Avoid Surface Water Drainage Issues with a Gutter SystemStanding water can ruin a property and pose serious issues to a community’s health. It can be a breeding ground for bacteria and mosquitos, and can lead to structural issues for buildings on the property. There can also be issues for adjoining properties, which can in turn will draw the ire of neighbors and possibly result in increased litigation risks. If you’ve ever had a property that has issues with surface water drainage, then you know full well the damage and headache it can cause.

… Continue Reading Avoiding Surface Water Drainage Issues

Combating Coastal Bluff Erosion

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Coastal Bluff ErosionLiving near the ocean is a dream for many, but the reality can be anything but. Property damage or loss caused by coastal bluff erosion can destroy the reward of a lifetime of hard work. First, what is a coastal bluff and what can happen to a property when erosion occurs? Coastal bluffs consist of the entire slope that lies between a marine terrace and the sea. They are formed when there’s a rapid uplift of the shore relative to sea level. Erosion is a natural process that occurs to bluffs over time and through various mechanisms, leading to instability.

Coastal bluffs are subject to erosion via several mechanisms, including creep, sheetwash, rilling and gullying and sudden collapses. Creep refers to the slow, downslope movement of a mass of sediment. A large factor in the promotion of creep is groundwater seepage, and engineering solutions include irrigation restriction and the installation of horizontal drains, or hydroaugers, and pumping wells.… Continue Reading Combating Coastal Bluff Erosion

Preparing Your Property for Seismic Retrofitting

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Los Angeles Requires Seismic Retrofitting

Los Angeles, California now requires Seismic Retrofitting.

As Californians, many of us have been waiting for “the big one” for years.

In 2015 Los Angeles set the nation’s strictest earthquake regulations. 15,000 of the city’s buildings will need to be retrofitted so that they can withstand the shaking of severe earthquakes.

Seismic retrofitting involves the process of securing buildings that may not have been adequately anchored prior to current retrofitting standards.

Most of the retrofitting will need to be done to the city’s apartment-style structures.

Smaller and medium-sized complex owners may not have the capital to complete their projects, but the city is offering various programs to help fund the cost. Also, many contractors have banks behind them and can offer financing to help fund the retrofit process.… Continue Reading Preparing Your Property for Seismic Retrofitting

How Can I Repair My Building and Property To Code?

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Code Compliance On Old Home Construction

Code compliance differs between old and new construction and repairs.

If you’ve ever been to Redlands, California, you may have seen its many historic buildings. There are dozens of Victorian-style residences and Craftsman era homes that date back more than 100 years.

I was recently talking with an acquaintance here in town that owns (and was looking to sell) an older home from the late 1800’s. He was telling me all about some of the renovations that he thought were necessary in order to bring the home up to code and make it habitable as a residence. There was a lot of work that needed to be done – ranging from replacing old electrical and plumbing work to repairing some damage to the structure that was a result of age and unstable land.

At one point, I was asked what I thought should be done about the structural issues due to the unstable land beneath the home? He was very concerned about what the city’s building department might require to repair the structure in order to sell it.  Since Helfrich-Associates has performed many investigations of structures that were built on unstable property, I knew he was probably dealing with issues that could range anywhere from minor cracks in the floors, walls, and ceilings, to difficulty operating doors and windows, to significant and serious foundation movement. If not repaired, these issues could discount the property value.… Continue Reading How Can I Repair My Building and Property To Code?

Weather Watch: El Niño And Slope Stability

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Weather Watch: El Niño And Slope Stability

Hurricane image courtesy pixabay.com

As we get closer to California’s rainy season, which is usually between November and March, meteorologists are warning of a record-breaking El Niño. El Niño is a warm weather pattern that can cause heavy rain in the Pacific Ocean and surrounding land masses, such as the Pacific Rim countries, including portions of the Western United States.

Over the last six months, California has experienced several major rainstorms. While this has been great for our rain-deprived residents, it’s wreaked havoc on the parched landscape created by the state’s record drought.  In fact, the drought has caused the soils to dry out, leading to surface cracks that will fill with rainwater.… Continue Reading Weather Watch: El Niño And Slope Stability

Warning: Falling Rocks

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Alpine: Photo of Damage

A photograph of the damage from falling rock.

Remember when, at the beginning of the Indiana Jones movie, Raiders of the Lost Ark, the scene where Indy takes a golden statue off of a pedestal and a giant boulder begins to tumble down a ramp, almost crushing our hero? Well, imagine that boulder at the top of a hill near your property. Now imagine it rolling down the hill, except your home or commercial structure isn’t Indiana Jones, and it can’t escape!

Helfrich-Associates recently was invited to help resolve just such a situation in Alpine, California. … Continue Reading Warning: Falling Rocks

Landslide Mitigation: Overcoming the Risk

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Landslide mitigation can help in areas prone to landslides, such as in Malibu, California. Image Courtesy Pixabay.com

Landslide mitigation can help in areas prone to landslides, such as in Malibu, California. Image Courtesy Pixabay.com

The city of Malibu is one of California’s most beautiful coastal destinations. Located along the famed Pacific Coast Highway, the area is framed by the Pacific Ocean as well as the Santa Monica Mountains.

While coastal zones and properties are highly desirable, they can be difficult to build on. In part, this is due to erosion, rainfall, soil composition, and poor grading. Malibu has steep, clay slopes that are prone to landslides.… Continue Reading Landslide Mitigation: Overcoming the Risk