City, homeowners play the percentages on flood control

Aug. 13--BARSTOW -- The sound of rushing water is something most desert homeowners don't expect, but it can become their worst nightmare.

The percentages say that nightmare will probably never happen to most Barstow homeowners. Unfortunately, just about every year disaster does strikes for just a few homeowners.

"The rule of thumb, about every 10 years the Mojave River will overflow. It doesn't always happen," Brad Merrell said. He is the consulting engineer for the City of Barstow. He grew up and lived most of his life in Barstow.

He also has been involved in all of the recent flood-control projects in the city. He has the FEMA flood plain maps to determine where the city's flood plains are located. But he can't determine where Mother Nature intends to strike during the summer months.

"These conventional thunderstorms. They hit every year, but we can't predict where they are going to be," Merrell said. "Sometimes they are in the Barstow Heights, sometimes they are in East Barstow. Sometimes they are in North Barstow. We are fighting storms every year."

According to Reference.com, convectional rainfall occurs when the warm air deflected from a landform rises and forms rain clouds. The storms caused by the convection process are known as air-mass storms and cover a small portion of land.

That is what happen July 1 in a small portion of Barstow above Rimrock Road. A small but destructive thunderstorm hit with hail and rain. In a matter of minutes, a wall of rushing water carrying mud and debris overflowed the Guadalupe Channel and caused severe damage to two homes on Creosote Court.

"The Guadalupe Channel, or East Barstow Channel, right now, is designed for a 100-year (flood). Where it (water) goes under the roads, Rimrock and Armory, I don't think it's 100-year. I haven't done the calcs (calculations) on it," Merrell said.

A 100-year flood is a flood event that has a 1 percent probability of occurring in any given year. A 500-year has a 0.2 percent probability.

"Unless we have a rain gauge (at site), I can't determine the event year. Just based on the intensity of the flows, it (storm) had the intensity of 500-year," he said. "It's really local where the clouds rise up. They go 30,000 feet and they dump their rain. We had rain turn into hail. It was the size of quarters. It did a lot of damage. It's all happening in this one area."

In this particular storm event, neither homeowner on Creosote Court had purchased flood insurance.

"To be honest, I went over there and talked to the two people that got flooded recently. They were not in a flood zone and required to purchase flood insurance," said City Councilman Tim Silva, who operates a mortgage business in Barstow.

The longtime Barstow resident knows where the various flood zones are located.

"I know Barstow very well. I can tell them (home buyers) right away if they are in a flood zone," Silva said.

But typically, Silva said most mortgage companies will require a homeowner to purchase flood insurance if the home is in a particular zone. There are different zones, according to the Federal Emergency Management Agency.

Homeowners can go to fema.gov to find out if their home is located in a flood zone. The Flood hazard areas identified on the Flood Insurance Rate Map are identified as a Special Flood Hazard Area (SFHA). SFHA are defined as the area that will be inundated by the flood event having a 1-percent chance of being equaled or exceeded in any given year. The 1-percent annual chance flood is also referred to as the base flood or 100-year flood.

According to the FEMA site, the moderate flood hazard areas, labeled Zone B or Zone X, are also shown on the maps, and are the areas between the limits of the base flood and the 0.2-percent-annual-chance (or 500-year) flood. The areas of minimal flood hazard, which are the areas outside the SFHA and higher than the elevation of the 0.2-percent-annual-chance flood, are labeled Zone C or Zone X.

Flood insurance can be purchased on the site as well. Barstow insurance agent Steven Stewart said the flood zone will determine the cost of the flood insurance. He said a homeowner in Barstow could spend $400 to $1,200 a year.

"It depends where you are in the community," Stewart said.

Often times, home buyers visit his office after receiving bad news from their lender that flood insurance is required.

"It's not that they are worried about having a flood in Barstow, 'please sell me flood insurance.' They only get it when they are forced to buy," Stewart said.

Merrell recommends that homeowners who may be worried about possible flooding look at several landscaping techniques instead of purchasing expensive flood insurance.

"I realize you have to pay that (insurance) every year. But doing that for several years you could have done some substantial improvements that would have protected you," Merrell said.

"I looked at some of the houses up there (Creosote Court). Some of the houses in the front yards they built walls on the front of their houses that don't allow the water to get out. That's the biggest problem you have. When you build a house, you want to elevate your house a foot above the low point and maintain a positive drainage around the house."

Merrell said homeowners also cause flooding issues by building fences, swimming pools and moving dirt around after final permitting is done when the home is built.

"They disrupt the positive drainage around the house," he said. "If you are in an active flood plain, you need to have good positive drainage that allows the water to go out before it goes through the house.

"If you are looking at 0.2 percent chance of flooding in your house, you are paying $450 a year. I mean, what's the payback on that? If it was me, I wouldn't buy flood insurance, but I would have positive drainage around the house. You spend money on landscaping, but you don't lose the house. But on the other hand, if I'm the type of person who doesn't worry about it, I would get the insurance.

"You can take the $450 a year, you could put that into a wall in the back of your house to keep water from coming in. That might be better spent. It's an individual decision and it's not something the city can say 'hey, you have to do this.'"

Merrell also said the city may make the builder of a new home follow certain requirements. That was the case with a home that is currently being built on Country Club Road.

"We required him to to raise the house up a couple feet so he's out of the flood plain. If the flood does come, his house will be high and dry, but he will not be able to leave his house because of all the flooding," he said.

"You can take your house out of the flood plain by filing with FEMA and a confidential letter of amendment. That takes an engineer and some paperwork."

The city recently finished several flood control projects and is in progress on others.

The Kitchen Dean Wash drainage project is among three improvement projects the city has worked on, courtesy of an $8.6 million grant. That drainage system is now protecting the east side of city from storm events.

Two other planned drainage improvements projects will be located at Laverne Avenue and Avenue I. Merrell warned the City Council in January the Laverne Flood Control Improvement project will not work as well as the Kitchen Dean Wash until the entire project is completed. He said staff would take El Nino into consideration, so additional measures like a cut-off wall would be added to prevent damage to the system.

Merrell said the improvements will not guarantee 100 percent protection.

"Nobody builds for a 500-year flood," he said. "That's a 0.2 percent chance of it happening every year. You can't justify the cost for that type of protection. That doesn't mean you shouldn't be actively working on protecting what we have and we are doing that. We have spent a lot of money the past year.

"I think we are more prepared than we ever have been," Merrell said. "The problem is Mother Nature comes up with these weird storms in one little area and it looks like we are not prepared."

Mike Lamb can be reached at 760-957-0613 or [email protected]. You can also follow him on Twitter @mlambdispatch.

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