Flood plain remap moves ahead

The message to town and nearby residents was, “Whenever it can rain, it can flood,” even if you’re not in a flood plain. A team of Boulder County, Federal Emergency Management Agency (FEMA), and local officials met January 23 at the library meeting room, with about 60 residents in attendance.

The Town, Boulder County, and federal officials are in the process of remapping Lyons and adjacent areas for flood risk. That includes houses that are in the one percent and .2 percent (formerly known as “100 year” and “500 year”) flood plains. One percent means that each year there is a one percent chance of flooding, regardless of whether there was a flood the previous year. (The reason for the change in terminology is that after a 100 year flood event, residents often think that they are safe for another 100 years. Not so.)

Whatever you want to call it, it does not account for the possibility of storm water flooding hitting Lyons in areas not even close to the two Saint Vrain creeks. For example, Welch Drive had flooding in 2013 from the rain runoff, as did Kelling Drive near Second Avenue. “Water flows downhill,” said Town Administrator Victoria Simonsen. Even some residents uphill from the streams sustained water damage due to runoff.

Simonsen noted that the proposed maps of the town and nearby unincorporated Boulder properties show risk for many residences, and she urged homeowners to take out flood insurance while the maps are pending. If your property was in the flood map previously, and it moves into a 500 year (.2%) zone from a 100 year (1%) zone on the future map, you have a limited time to get a so-called preferred policy. In this instance, the homeowner could get a refund of some of their current insurance bill. If you don’t have flood insurance, you can normally get a policy with your mortgage lender at the preferred rate.

Flood insurance is required if you have a mortgage and you’re in the 1% or .2% flood plain. Simonsen said that people within the flood plains will get door hang tags to alert them if they don’t already know that they are at risk.

The Colorado Hazard Mapping Program (CHAMP) and Mile High Flood District are involved with mapping flood risk around the area. The streams they have looked at include 230 miles in the County and a total of 470 miles in the area. The process of identifying high-risk areas includes aerial mapping, which presenters said was highly accurate, and on-the-ground measurements of stream channels, floodways, and fringe (overflow) land.

While these newly mapped areas are fairly accurate, presenters urged caution that the results can be affected by dam failures, bridge and culvert clogs, debris, and fires that have burned vegetation that would have allowed for more absorption.

The terms “flood plain” and “floodway” may be confusing to some. A flood plain, whether in the 1% or .2%, has fewer building restrictions than the floodway. Basically, the County and the town of Lyons don’t allow the building of any structures in the floodway that could impede the flow of water and affect properties downstream. The current FEMA mapping dates back to the 1970s. The County is already using the new data, with the Town set to begin using it by the end of February.

Once declared to be effective, the best available data being released now will give property owners a 90-day comment-and-appeal process with a preliminary Flood Insurance Rate Map (FIRM). During the appeal period, there must be technical data in the form of a survey, certificate of elevation, or topographic maps. Legal notices of the maps’ completion will appear in local papers of record. The preliminary data shows that about 30 properties moved from the flood plain into the floodway. Conversely, other properties that had been in the floodway are now in the flood plain. And a few properties will now be totally out of even the 1% zone.

Once property owners learn their status, the results can be appealed to the Town or County, depending on the homeowner’s jurisdiction. Property owners can use their address to access the map at www.BoCoFloodplainRemapping.com. This must be done during the 90-day appeal process, which is expected to begin in March. The County will forward any appeals to FEMA. The new maps are not expected to be official until early next year. Homeowners in the town of Lyons can check with officials to see what their home’s status is.