The 2013 Colorado Floods

In 1994, Gilbert White created the Boulder Creek Flood Notebook (BCFN), a comprehensive plan, available both in print and on-line, for studying the next great flood to strike Boulder, Colorado. The proposed research would examine both the effects of such a catastrophe – the loss of life, property damage, social disruption, and environmental destruction – and the decisions that made those effects possible. The Notebook includes a detailed directive for disseminating the findings of that research to decision makers, both locally and nationally, to ensure that the mistakes made in Boulder will not be repeated. Gilbert also donated funds to the University of Colorado to support the research once the next great flood occurred.

The resultant report was to be entitled "The Boulder Creek Flood of [year]: A Community Choice." As Gilbert says in the preface to the BCFN, it is

"intended to provide an initial estimate of the catastrophe... From it, the citizens of Boulder may be helped to understand how their community came to be vulnerable to the flood, and the kinds of decisions that may either reduce or enlarge the human consequences of the next large flood."

Gilbert first became interested in what was happening in the Boulder Creek floodplain in 1957 when he began spending summers in Boulder County while still chair of the Department of Geography at the University of Chicago. Subsequently, in 1994, after he had moved to the University of Colorado, Gilbert described the major decisions that had exacerbated risks along Boulder Creek over the previous century. (A summary of those findings is available on the BCFN web site.)

The BCFN remains a remarkable document and undertaking, as well as a tribute to the prescience and wisdom of Gilbert White. Still, in two respects (that Gilbert probably could not have foreseen) it is incomplete as a guide for studying the massive floods of September 2013 in Boulder County.

Payson Sheets: Gilbert White's vision saved Boulder during flood http://t.co/IdHCQXYImk Well said, my friend, well said! #boulderflood

— Terri L Turner (@floodplaingeek) September 19, 2013

First, the BCFN was designed to examine, almost exclusively, poor decisions that increased risk – typically, decisions that enabled the construction of inappropriate structures and other uses in the floodplain. But the floods of September 2013 demonstrated a much wider range of decisions and effects, including positive actions that unquestionably limited damage and injury. Warning systems, for example, appear to have worked well. Perhaps even more importantly, the renovation of the Boulder Creek floodplain over the previous several decades, involving the removal of inappropriate structures and the institution of more suitable uses, well demonstrated Gilbert’s notion that humans should adapt to the hazard posed by floods as much as (or more than) floodplains should be structurally modified to allow human uses. As Gilbert said in his landmark doctoral dissertation,

"Dealing with floods in all their capricious and violent aspects is a problem in part of adjusting human occupance to the floodplain environment so as to utilize most effectively the natural resources of the plain."

Next City explores Boulder's flood planning and the influence of Gilbert White

Unfortunately, not all of the neighborhoods and communities along the other drainages of Boulder County were as well prepared.

And that points out the second mistaken assumption of the BCFN: that the next great flood disaster affecting Boulder would be a flashflood along Boulder Creek. That supposition is entirely understandable; floods in Colorado and, indeed in most of the arid American West, are typically associated with severe inundation over a single drainage system – i.e. with flashfloods. As a flashflood, however, the inundation along Boulder Creek in September 2013 was not unprecedented. In fact, the flood apparently only reached the “50-year” level. What was unprecedented was the geographical and temporal extent of the severe precipitation that occurred during the week of September 9, 2013. (Some meteorologists have described the 15” to 17” of rain that fell along the northern Front Range as a “1,000-year” event, although ascribing a frequency interval to such an extremely rare event is a bit ridiculous.) Virtually every drainage along the northern Front Range incurred severe flooding, and areas far beyond usual drainages were also deluged. Indeed, Boulder got off relatively easy compared to the neighboring towns of Lyons, Jamestown, and Longmont. Again, Gilbert designed a study to examine a flash flood on Boulder Creek; the BCFN did not anticipate the breadth of the disaster that occurred in September 2013.

Visualization of the extreme precipitation the Front Range experienced. A 38-second version is also availabe. Courtesy of NOAA NCDC

These problems notwithstanding, the BCFN remains a tribute to its author. Gilbert was 83 years old when he created the Boulder Creek Flood Notebook. Clearly he wanted to establish a program that would continue his work and further his goals after he was gone. Ironically, the Boulder flood of September 2013 not only provided an opportunity to do just that, it also provided vindication for all that Gilbert had done in the seven decades of his career as an advocate of wise floodplain use and adaptation to floods. The flood did uncover failures in planning and decision making, but it also showed that humans are learning to adapt to their sometime hostile environments – albeit not quite as quickly as Gilbert would have hoped.

-- David Butler