Opinion: Don’t do flood planning using the rear view mirror
Back almost 30 years ago, when I was on the City Council, we engaged in a very detailed study of the major drainages that flow through Boulder, and the likely damage that could result from floods. Our objective was to come up with appropriate risk mitigation standards. Council member Spense Havlick and I even went to CSU and tried to walk across their artificial flume at various flow rates and depths to test our ability to walk through a flood. Out of this study came Boulder’s regulatory standard using the 100-year and 500-year flood maps and also the high hazard areas, which were based on such flows. The “100 year flood” is a statistical notion that uses historical data to attempt to indicate what areas would have a 1 percent probability of flooding in a given year. The “500 year flood” has an annual probability of 0.2 percent. Setting the rules based on these standards was a compromise. The council did end up requiring some buildings that were at very serious risk to be torn do