- Scott Brookhart PE, CFM, Associate Cary, NC
This week’s blog was written by MA Engineering’s Scott Brookhart, Associate, Hydrology. View MAEC’s Hydrology projects.
Recently, Mr. Bookhart was instrumental in helping MA Engineering receive approval from NCDOT to perform Tier III Complex Hydraulic Design (Work Code 479) and Tier IV UHE-National Flood Insurance Program (Work Code 480), in addition to our existing prequalification for Tier I & Tier II.
On the evening of July 16, 2016 approximately 3-5 inches of rain from a slow moving line of thunderstorms fell in the Raleigh-Cary, NC area over the course of a few hours. For the Town of Cary this was an exceptional albeit short duration event that resulted in significant flash flooding. It took only minutes for creeks, road crossings, and drainage networks to surcharge or overtop resulting in stranded cars, water rescues and personal property and infrastructure damage.
As a water resources engineer who has spent years modeling floodplains and studying watershed management I expected to see areas designated as regulatory flood zones inundated, but what surprised me about this flash flood was how much the upper reaches of smaller watersheds were impacted. Just down the road from where I live our local street overtopped with approximately 3-4’ of water making it impassable for short period of time. This was in a non-regulatory flood zone with a drainage area of less than 0.4 square miles. Thanks to strong buffer and stormwater management requirements enforced when this sub-watershed was developed, the natural stream had room to flood and only had impacts at the crossings and in a few yards. However, it reiterated for me the power of the natural system and the futility of trying to contain it. We should be focused on working within the natural framework as much as possible.
With the mix of climate change, the potential for higher frequency and intensity storm events, and continuing development in our communities, it is inevitable that events like this one will have more and more impact as the levels of runoff increase, despite implementation of many solid stormwater programs. Older infrastructure will continue to have a hard time keeping up, and the level of flood risk to individual property owners and communities can increase without continued action.
There are efforts at the national, state, and local levels to better identify flood risk and focus on building resilient and sustainable communities. Resilient communities will be better able to identify and mitigate flood risk through access to better flood risk data and outreach methods. As a Water Resources Engineer I view it as my responsibility to promote watershed management that not only looks at solutions for stormwater management and water quality but for floodplain management as well. A complete watershed approach is necessary to give the natural systems a chance to function as intended and/or restore functionality within our growing communities.
Whether the project is a roadway improvement project, a subdivision, a park, a stream restoration, or a commercial development; we can look at these projects from a complete watershed approach and think beyond the minimum regulatory requirements. There are obviously many challenges to promoting these concepts within the industry and the public arena such as changes to the regulatory environment, the cost of implementation, and raising public awareness.
At MA Engineering we support continuing the conversation and advancing the science to help our clients see the benefits of these enhanced approaches to complete watershed management for resilient and sustainable communities.
View MAEC’s Hydrology projects.