Las Cruces Study Says FEMA Flood Maps Contain Errors

The Federal Emergency Management Agency’s draft flood plain maps for Las Cruces, N.M., contain significant errors that could force some homeowners to pay more in insurance, officials said.

Public concern over the accuracy of the maps prompted FEMA to suspend a 90-day comment period when the maps were presented in May.

Since then, a study done for the city by Bohannan Houston Inc., confirmed there are errors in FEMA’s maps — old information, high estimates for rainfall and drainage projects that weren’t accounted for.

Rob Richardson, senior vice president of Bohannan Houston, told a City Council work session that hydrology studies about historic runoff patterns and flood control infrastructure under U.S. 70 were not taken into consideration.

FEMA, for example, didn’t show water crossing U.S. 70, said the company’s Brad Sommerall. The flood plain could be significantly smaller with those crossings factored in, and with plans to construct a 125-acre retention pond.

“There were some assumptions made that need to be rectified,” Sommerall said.

He said that not every area identified in FEMA’s preliminary maps will be removed from the flood plain, but that more analysis is needed before the project moves forward.

The flood plain could affect up to 9,000 properties throughout Dona Ana County in terms of insurance, including many on the city’s east mesa off U.S. 70.