Flood Control Project Underway To Shore Up Logandale Levee

By VERNON ROBISON

Moapa Valley Progress

Heavy equipment operators have been hard at work since earlier this year on a major flood control project at the north end of Logandale. Their work site is along the Muddy River flood channel, just below the Well Siding diversion dam, near the west end of Wells Ave.

The site has long been an area of concern for flood control planners. A high embankment meant to keep the stream in its channel is merely an earthen berm with an unclear history. It is apparently the work of generations of local farmers who built and rebuilt the embankment over the years; bringing in dirt and other materials from the fields and piling it up as a flood barrier to keep the stream flow contained during floods.

That may have been good enough when there were just agricultural fields and only a handful of farm houses in the area below the levee. But with growth in the community over the past two decades, the neighborhood has changed.

The old earthen levee has never been completely reliable in the event of a major flood event. In 1981, for example, a major cloudburst hit the California Wash drainage area near I-15 south of Glendale. The storm produced a huge floodflow that came right through the Moapa Valley. During that event, the stream broke out of the north end of the levee, just below the diversion dam. From there it swept through the fields and homes in the area that is now Country Lane Estates and its surroundings. As a result, the damage to homes and property was catastrophic in the area.

A similar event nearly occurred again in the flood of 2005. That year, the levee began to give way in nearly the same location. If not for the quick action of a local resident of the area who had access to heavy equipment, the outcome might have been much worse. The breach was hastily repaired and the disaster was averted.

After that, County authorities identified the levee as a place that needed attention. They began planning a project to redesign rebuild the levee.

By 2010, the project was still in design phase. It was around that time that the Federal Emergency Management Agency (FEMA) took a close look at the levee in Logandale and declared that it did not meet federal standards as a flood control structure.

As a result, a large area of Logandale just south and east of the levee was suddenly mapped into a 100-year flood zone. This zone includes much of the lowland valley areas south of Wells Avenue running south as far as the Cram Avenue alignment. The change required more than 200 Logandale households in that area to purchase expensive flood insurance policies.

Since that time, Clark County officials have worked to acquire the necessary rights of way along the channel, which were privately owned, to commence with the project.
In 2013, Waite Avenue was paved by the county, with the idea that it would prepare for the heavy equipment traffic that would need access to the area when the project commenced.

A request for bids on the levee project went out in 2015. Late last year, the bidding project was closed. And earlier this year, the bid was awarded to Trade West Construction in the amount of $6.7 million.
The project involves reworking about a half mile of the flood channel. The contractor began earlier this year, removing all of the vegetation and other debris from the project area.

Crews are currently in the process of removing the old levee. Since no one is sure what materials lie beneath the earthen structure, the contractor is being required to remove it all and relocate the material to an adjacent site to the north. It is expected that much of the same material will be brought back to the site to form the base for the sloping embankment walls that will the be built.

With the levee being removed, though, it could leave the surrounding community in a bind if a major flood event were to occur before it is rebuilt. Thus, the contractor is under the gun to get the project completed before flood season returns in the late summer.
“We will all just be crossing our fingers that we don’t get a big flood within the next few months,” said Janice Ridondo, of Commissioner Marilyn Kirkpatrick’s staff, during a tour of the site last week.

The design for the project calls for concrete lining of the channel. On the east bank the slope down to the stream will be concrete from the Wells Siding diversion dam for around 2600 feet down the length of the entire project. Along the foot of the slope, the contractor will first pour a concrete cut-off wall which will extend down eight feet deep. This will provide a solid footing for the slope lining wall which will be poured later.

On the west bank, along the railroad tracks, there will be somewhat less concrete. Stone rip-rap will line the channel for the first 300 feet below the diversion dam. This will then transition to a concrete slope similar to the east bank.
The bottom of the channel is expected to be left in a mainly natural state.

In the early design of the project, local residents of the area had asked that their traditional access down to the stream would be somehow preserved. They were particularly interest in accessing a natural pond located in the stream about 1,500 feet below the diversion dam.
In response, county planners included access points to allow members of the public to climb down the concrete channel to access the pond area.

Unfortunately, residents might find quite a different stream there than they remember, by the time the project is completed. The cherished pond has recently been posing a problem to county engineers. They are concerned about being able to place the 8 foot cut-off wall through the area directly adjacent to the pond. It is unknown just how deep the pond is, or what exactly the soils are comprised of at the bottom of it.
“The engineers are wanting us to drain the pond completely so that we can look and see what we are dealing with there,” said Dean Mills, Quality Control Coordinator for Trade West Construction, last week.

If done, that process would most likely do away with the small pond as it has naturally existed in the past, Mills said. But a final course of action was far from being decided on the matter last week.
Once this major project is completed, a large segment of Logandale is expected to be safe from a major flood event. The county staff will then work with FEMA officials to order a remap of the area. If all goes according to plan, the flood plain designation to the area will then be lifted and the residents in the area will receive some relief from high flood insurance premiums.