Flood threat is real

(In response to an article titled "City updating flood map," published 11-10-10 in the Longmont Times-Call.)

There is no simple way to prepare for flooding of the kind that roared down the Big Thompson canyon in 1976. The National Weather Service reported that besides wreaking havoc, that storm caused 150 deaths, a new high in Colorado’s recorded history. (100 people died in a flood near Pueblo in 1904.)

Headwaters of both the Big Thompson river and the north branch of the St. Vrain river (Longmont's major stream) lie in roughly the same territory, which tells me (and I’m no expert on this subject) that, by a quirk of Nature, the 12 inches of rain that fell in five hours over the upper Big Thompson canyon could just have easily hit the St. Vrain runoff instead.

Fortunately, because of its distance from the mouth of Big Thompson canyon, the city of Loveland escaped most of the wrath of the 1976 flood. Longmont holds a similar advantage, but its flood mitigation efforts are complicated by the fact it straddles two major drainage basins: the St. Vrain river and Lefthand creek, which originates in the northern Indian Peaks Wilderness area.

Possibly most vulnerable to a 100-year flood is the city of Boulder. Unlike Loveland and Longmont’s distance factor, Boulder’s downtown sits right at the mouth of Boulder Creek canyon, with Barker Dam at Nederland providing about the only protection. Also flowing through Boulder is South Boulder Creek, downstream from Gross Reservoir.

I’m glad our city officials recognize Longmont’s vulnerability to flooding. But in this county, for reasons I don’t understand, the public seems to be much more anxious to buy land to look at, rather than investing in flood mitigation to save lives and property.

We can fight and argue over chickens, trains and airport runways. But unlike flooding, those issues are hardly of life-threatening proportions. (And no, I don’t live on a floodplain.)