The Year in Review
One of the advantages of editing this publication is that I get to read the boss’s column before writing this one. It turns out that he covers several items I was going to address, so I urge you to read his column, beginning on page 2, if you have not already done so.

We continue to be just about maxed out on development referrals, and it is a constant struggle to assure that new development doesn’t increase the flood hazard potential within the District.

Our maintenance eligibility program has expanded under David Mallory’s direction. He currently has about 110 separate projects somewhere in the process between design review and final acceptance of construction. He also put together a one day seminar on the program for local government staff and developer consultants. Although the attendance was good, a number of developer consultants who could have definitely benefited from the seminar failed to attend, and their submittals continue to show it.

Kevin Stewart continues to assure that we have the best possible flood detection system, and he continues to be in demand as a international expert in this field (see his list of professional activities on page 22 and his column in this issue). If you check out our web site at www.udfcd.org you will also see Kevin’s handiwork.

Last year I reported that I had been trying for five years to negotiate intergovernmental agreements between Denver, the Rocky Mountain Arsenal, Commerce City, Adams County and the District for the implementation of the Irondale Gulch master plan, and that I thought 1999 would finally be the year. Wrong! Although we did make progress we didn’t get it done and I am now out of the prediction business.

We have started a master plan revision process for the lower portion of the First Creek watershed, and have been working with Aurora, Denver Gateway Regional Metro District and Oakwood Homes on a cost sharing agreement for implementation of the regional detention facilities called for in the upper First Creek master plan.

We have also begun revising the South Boulder Creek master plan. Our first step was to revisit the hydrology, and preliminary results indicate that the discharges will probably be going up. Stay tuned for this one.

I have continued to represent the National Association of Flood and Stormwater Management Agencies (NAFSMA) as an advisor to the Technical Mapping Advisory Council. I really respect the amount of hard work the Council members, including Brian Hyde from the Colorado Water Conservation Board, have put into their recommendations to FEMA, and FEMA’s proposed map modernization plan. Unfortunately, unless and until FEMA receives some significant funding source ($750 million over seven years), most of these recommendations will languish.

What Colorado Can Do To Reduce Its Vulnerability To Flood Disasters

Governor Owens recently hosted a Flood and Drought Preparedness Conference. This is how I would have answered the flood part of his question: "What Can Colorado Do To Reduce Its Vulnerability To Flood and Drought Disasters?"

Background
Floods happen all the time. We only notice them when they occur in areas we have developed, and they are large enough to cause damage and/or loss of life. In response to ever increasing flood losses, efforts have been made to reduce these losses through the construction of flood control projects such as dams and levees; and later, through efforts to reduce development in floodplains. Still the losses continue to mount. Let’s examine why this is happening and what the implications are for Colorado.

The 100-year flood is the national standard for planning for floods, and has been for more than 25 years. It has a 1% chance of being equaled or exceeded in any given year, or about a 25% chance of being equaled or exceeded over the life of a 30-year mortgage. Larger floods are used in the design of some facilities; such as dams, to insure against a catastrophic failure.

The selection of the 100-year flood standard has perhaps left us with a problem similar to the Y2K situation. When early computer developers used two digits for the year, the next century was way off. So we had a multi-billion dollar problem to fix.

Similarly, the 100-year flood probably seemed like an extremely rare event when the Congress established it as the standard. We try to manage the 100-year floodplain, with some exceptions that I will discuss later, and we accept, whether intentionally or not, the damages from larger floods. However, this happens often enough somewhere in the country that the flood damages suffered by the nation continue to increase. Perhaps, as with the Y2K decision, we have gotten ourselves into a bind we need to fix.

When I first got interested in floodplain management, as a result of seeing the effects of the 1972 Rapid City flood up close and personal, the research literature had three general ways to address flood hazards: 1) keep floods away from development (structural flood control), 2) keep development away from flood prone areas (non-structural measures), or 3) spread the loss burden (flood insurance).

Where Are We Today?
Today we still have the same three basic options available to us. The themes are somewhat varied but the bottom line results are the same. When the Urban Drainage and Flood Control District began operations in 1969, one of its first decisions, and one of the most important, was to adopt a two-pronged approach of fixing past mistakes while keeping new ones from being created. This included formulation of master plans for remedial flood control projects and the construction of those flood control projects as funding permits; in conjunction with the delineation and regulation of 100-year floodplains.

Having followed that course of action for 30 years, we can now say that while the District’s population has increased by about 850,000 people, with all the structures that accompany those people, the total number of structures located within the defined 100-year floodplains has decreased by more than 4000 structures. Twenty-five years ago, flooding was almost an annual occurrence along Westerly Creek in northeast Denver, Lena Gulch in Wheat Ridge, and many other locations. Now, you seldom hear about them, even though we have had many rainfall events that would have caused the flood damages we used to experience.

While this is a real success story we still have thousands of structures located within the 100-year floodplains in the Denver area and throughout the state, and many thousands more structures at risk from larger, less frequent, floods. Obviously, the occupants of those structures are also at risk. These floods are also what are termed flash floods, which means that they happen in a hurry, limiting our ability to conduct emergency efforts to protect structures.

Earlier I said that we regulate the 100-year floodplain, with some exceptions. What I meant by that is that current National Flood Insurance Program (NFIP) regulations allow quite a bit of development in 100-year floodplains. Without getting technical, the regulations allow development in portions of floodplains that can cause the flood levels to rise as much as a foot, without protecting either the new development or any existing development from that extra foot of flood depth.

Also, the NFIP maps floodplains based on existing watershed development even though it is well known that urbanization of watersheds dramatically changes the hydrologic regime, including increasing flood discharges from any given rainfall event. Some flood control projects, such as flood control channels, can increase flood peaks downstream by reducing floodplain storage. Allowing developers to fill parts of the floodplain has the same effect.

Fortunately, within the District, the local governments use 100-year floodplains based on expected future urbanization of the watersheds; many do not allow the full one foot rise; and all of them require some amount of protection against that increase in flood depth. We also have a substantial flood detection and flood warning system in place.

We are apparently expecting an additional one million people in the Denver area over the next 20 years. Even if we can keep every structure that is built for those one million people out of every 100-year floodplain, Colorado’s vulnerability to floods is going to increase, because larger floods can and do occur, as we know from the Big Thompson flood in 1976 and the Fort Collins flood in 1997. We also have the threat of dam failures, as happened to Estes Park in 1982.

The Answer to the Governor’s Question
The only way to reduce today’s property loss vulnerability is to continue to fix the mistakes of the past by pursuing remedial projects. Those can be structural projects like flood control dams and enlarged flood control channels, or they can be non-structural projects, such as acquisition and relocation or demolition of structures, and return of the floodplain to open space uses more compatible with the flood hazard. At the current funding level we are many years away from removing even the 100-year flood threat from thousands of existing structures. There is no alternative to increased funding if a near-term reduction in vulnerability is the goal.

Therefore, we need to continue to encourage owners of structures in floodplains to obtain flood insurance. And we need to improve and expand our flood detection and flood warning and response capabilities. We can also have recovery plans ready to go so that we can respond to the next big flood, recover from it, and mitigate against it happening again in that area. These activities also require funding, but at a much lower level than traditional remedial projects.

For future vulnerability, we need to continue to keep new development out of the floodplains as much as possible, and we need improved tools to be able to do that. Tax credits for donating floodplain land for open space, wildlife habitat, etc. is one example of an improved tool.

We can also revisit the 100-year flood standard and make a conscious decision to keep it and accept the damages that come from larger floods; or decide that the State of Colorado wants to adopt a higher standard. NFIP regulations allow it and FEMA encourages it. We can also revisit the floodplain management criteria for development in the floodplain. Other states have adopted more restrictive criteria than the NFIP minimums. Colorado could do the same. NFIP regulations allow it and FEMA encourages it. These are policy matters with little budget impact.

We need to continue to produce watershed master plans which can be used to guide new development throughout the watershed, and not just in the floodplain.

Summary
Colorado has thousands of structures and their occupants at risk from 100-year floods; and thousands more at risk from larger floods and/or dam failures. We have spent the last 25 to 30 years using essentially the same tools to address those hazards, and to try to keep things from getting worse in the face of a burgeoning economy. To correct the existing hazards will cost a lot of money. There is no way around that. We can improve the tools available to us to prevent new problems from being created by new growth in Colorado.

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