Flood Barrier USA

Tiny Nevada Town Flooded by Failed Dam

Author: Donna Conneely

In early February a Nevada earthen dam failed and caused major flooding, in spite of the fact that the dam had passed an inspection just months before. The dam did not pass the inspection with flying colors, however, and the participating hydro-engineers produced a list of recommendations for improvements that did not receive follow-up attention. This type of lapse is very common, especially in rural areas that may be burdened with low budgets and aging infrastructure.

The dam that failed is called the Twentyone Mile Dam, and it is designed to hold water to be used for irrigation in Elko County, Nevada. The dam is not considered a high priority installation, because it is located in a deeply rural area — any failure of the dam is not expected to cause loss of human lives. Nevertheless, the failure caused major flash flooding that wiped out a nearby state highway and flooded out nearby homes and ranches.

About thirty homes were flooded by the dam failure, and a full ten miles of the main highway was closed due to the washed-out roadway. It is impossible to overstate the importance of a main highway to a rural community — without this lifeline, transportation and access becomes almost impossible for the entire community. The community most affected by this event is a tiny town called Montello, Nevada, population 84. All the residents of Montello were impacted by the flooding caused by the failed dam — either due to direct flooding of their homes or from being cut off due to the highway closure. Not many people were affected by this flooding, thanks to the sparse population of the area, but those who were affected have suffered massive inconvenience; and in some cases, moments of terror.

Unusually heavy rainfall is being blamed for the failure of the dam. Earthen dams can be weakened by many factors, including seepage, root systems, erosion, and age. In the case of the Twentyone Mile Dam, a sudden and catastrophic breach occurred, causing almost instantaneous flash flooding that coursed through the countryside and directly across the important state highway that leads to Utah. One trucker who was on the highway at the time of the flash flooding came very close to losing his life. Seeing that the road was breaking up beneath the wheels of his truck, this lucky driver floored the truck’s gas pedal for several miles, surrounded by rising water and watching in the rear-view mirror as the road crumbled behind him. He made it to safety, but had to spend a nerve-wracking night in his stranded truck, watching roiling high water all around him throughout the night.

Repairing the dam and the damage caused by its sudden failure was at first thought to be a matter of weeks. Now, however, engineers have had a chance to more completely survey the extensive damage caused by the flooding, and the repair schedule — with its hefty price tag — is known to be much more onerous than initially hoped. Tiny Montello is now nationally famous for this disastrous flood, which all but wiped it off the map.

March 20th, 2017  |  Posted in Flood Protection  |  No Comments »

Winter Storms Cause Widespread Flooding in California

Author: Donna Conneely

After destructive wildfires ravaged large swaths of Southern California last summer, all those living close to the burn areas immediately began to fear large rainstorms. This may seem counter-intuitive; wouldn’t rain help heal the burned zones and begin the process of re-forestation? While it is true that rain is sorely needed in this drought-ravaged region, and this copious precipitation will indeed promote new vegetation, the storms that struck this week came too soon. There has not yet been enough time for new plants to develop the deep root systems needed to hold the soil together, and the heavy storms swiftly washed away the loose, sandy soil that had been denuded by the fires.

Southern California is not often affected by the type of dreadful flooding that regularly scours the southeastern region. As floods are infrequent and relatively harmless, most property owners do not carry flood insurance and are likely to lose everything in the event of a heavy flood. That nightmare scenario became a reality for some this week, as three consecutive winter storms lashed the area, causing major flooding and widespread damage to roads, bridges, and other infrastructure. Two deaths have been attributed to the storm, and there were many evacuations and rescues, including at a homeless encampment and a popular recreational campground.

California is still struggling to emerge from a drought that has devastated agriculture, wildlife, and even the famous ancient sequoias that have surely seen many severe droughts. The past year has brought much more rain than usual, and it is hoped that the silver lining of these recents storms will be a replenished water table- at last! But this future silver lining does nothing to assuage the immediate suffering that has ravaged almost the entire state — from San Diego to Sacramento. For the past three weeks, rain has pelted the state relentlessly, with very few breaks, and major flooding has caused havoc in many areas.

In particular, dramatic news photos show horrific damage at a low-lying campground called El Capitan, which is close to Santa Barbara. Fortunately, the campers managed to seek higher ground in time to avoid loss of life, but several cars were washed away and were later found mired to the roof in sand and seaweed on a nearby beach. In addition to the heavy flooding, the storms also caused widespread mudslides and rockslides that damaged major roadways badly enough to warrant closure. Trees loosened by soggy soil and heavy winds crushed homes in several areas, and flash flood warnings were announced across the state.

All this rain that fell at lower elevations appeared as snow at higher elevations. Some parts of the Sierra Nevada mountain range currently have double the average snowfall so far this year! This is very good news for ski resorts, and the reservoirs that are now brimming with water will delight farmers. But the threat of flooding from what is likely to be record-breaking snowmelt will continue to be a cause for worry through the spring and into the summer months.

January 23rd, 2017  |  Posted in Flood Protection  |  No Comments »