Preparing for a Disaster

As I muddle through the plethora of options on flood recovery and mitigation in Downingtown, I have been struck by the FEMA and PEMA staff's professionalism. We have been able to make inroads in flood recovery due to their involvement and participation.

It appears that I will be able to effectuate a buyout of a couple of blocks of homes, and we are looking to create a way for people to alleviate the repeated damages. There is a metric for discussing damages, and it involves addressing each property and determining the level of damage as a subset of the impact on the community. 

I have been able to access an Excel spreadsheet of properties in the flood plain and now have a pretty good idea of the size of the problem. As I looked at the flood maps and the designations of flood-prone areas, it followed the Brandywine and all of the tributaries. If there is not something done soon to mitigate the flooding, there will be issues in the future that will lessen the value of the properties.  

I thought about it for a while and pondered what would be a good strategy. I believe that the best-case scenario for the borough would be to train some people to interpret the aid packages for future flooding. There will need to be about ten people schooled in the programs available to meet the demand when there is an emergency.

When you look at the possibility of having quick response, having the procedures institutionalized locally will be of great benefit to the people who are affected by the disaster. The common thread during the last recovery was lack of information and putting people in a position where they need to fix after a disaster.

There are a lot of plans and publications out there that I never would read. For example, as I look through the planning documents that Chester County has for Downingtown emergency response, I read the following:

Within Chester County there are 36 dams that meet the state's definition of a high hazard dam. Of those, there are thirteen that meet the category 1 criteria meaning there is a substantial population at risk (numerous homes or small businesses or a large business or school) in the inundation zone.

I had to read through the County Plan during the buyout program because the flood destroyed the Downingtown Flood Mitigation Plan. If the plan had remained intact, I never would have learned that. However, I felt a little uneasy once I learned it. It is a paragraph in the Downingtown section of the plan. If a dam breaks above me, I could die if I do not get the word. I could be sitting in my living room, sipping the beverage of my choice, watching CNN, and the next thing you know, my house would be destroyed in a water surge.  

Downingtown had a 1000-year flood. A 1,000-year flood has a 0.1 percent chance of happening in any given year. But Records only date back about 150 years depending on location, as we don't have records that date back to 1021. 1000-year floods have been proven to occur multiple times in a given location. For example, New York City had "Ida" classified as a 500-year flood. "Superstorm Sandy" was also a 500-year flood, and there were only nine years between Ida and Sandy. Southeast Texas had 500-year floods for five straight years, starting in 2015.

If you look out west recently, Seattle, Bellingham, and Quillayute set records for 90-day rainfalls. Blizzard warnings on Hawaii's Big Island’s summits with 12 inches of snow and 100 mile an hour winds. Meanwhile, Denver has had the third-longest stretch in history with no snowfall.

The borough is starting a technical committee to assess the flood and make recommendations for flood control, but this seems like it has to be a separate committee. Therefore, I will seek to form a third committee, the Dam Committee. 

The Dam Committee will be a complicated committee both in makeup and task. There need to be oligarchical members of the community, there need to be people who speak Dam Speak, and there will probably need to be people with a sense of purpose. Having people with a sense of purpose is a key in any effort.  

The Dam Committee will seek to work with Probable Maximum Precipitation (PMP) to derive the greatest depth of precipitation for a given duration meteorologically possible for a given size storm area at a particular location at a particular time of year. 

Once the Dam Committee is comfortable with the PMP. They will have to look into the Probable Maximum Flood (PMF), which is the largest flood that could conceivably occur at a particular location, resulting from the probable maximum precipitation (PMP) and, where applicable, snowmelt, coupled with the worst flood- producing catchment conditions that can be realistically expected in the prevailing meteorological conditions. 

It seems complicated, but I think … once all the information is available, all the analysis is complete … Dam Committee will end up looking at creating a Dam. But, I also feel that there will be opposition to any conclusion that the Dam Committee wishes to enact.

Barry Cassidy is a freelance grant and economic development consultant. He can be reached at