By: Julie Steenson, Office of Performance Management
Few people realize it, but KCMO has more than 5,000 road crossings of streams, generally via pipes and culverts that run under roadways. Also, over 2,400 structures currently fall within the regulatory floodplain – or areas that could easily flood. There are also perhaps 5,000 to 6,000 structures (industrial, commercial residential) in high flood risk areas throughout the City limits.
Let’s put this in perspective on what it could mean for you – a crest of flood waters on Blue River, which is located right in the heart of Kansas City, will travel from State Line north to the Missouri River in approximately 12 hours. That is the amount of time emergency management and public safety officials have to close streets and structures at risk in the potential flood area and evacuate this highly populated area.
In this post, we want to highlight how one of our data points is collected and how it may just save your life.
Over the last 15 years, the Water Services Department, in partnership with the Office of Emergency Management, have quietly created and carefully installed a sophisticated system of rainfall and stream level sensors that monitor areas prone to flooding. These sensors help to anticipate changing conditions of our rivers and creeks throughout the city. Data collected from the sensors, called the Flood Warning System, can provide emergency responders with enough time to barricade, close and evacuate areas identified as flood threats. These warnings and data also assist the City in coordinating and communicating critical messages to the public both directly and through the National Weather Service. The flood warning system allows the City to mobilize many forms of emergency response even before floods occur on streams and rivers.
Here’s how they work in a nutshell: A sensor site creates time stamped “tips” (amounts) of rainfall over time at a location which is transmitted by radio to computers in real-time. The timestamps and amount of rain data allows staff to determine the amount and intensity of the rain fall and determine the duration of each rain event. This combined info lets staff determine how severe a rain event was. But rainfall totals do not easily tell you what will happen on the ground. Will the sidewalks in Brush Creek or Barry Road by Maple Woods Community College flood? And if so, when will this happen? Rainfall alone cannot easily predict or confirm how bad water levels in streams may get. For this reason, most sites with rainfall sensors also have a Pressure Transducer that can report on the weight/height of water above the Pressure Transducer sensor. As a stream elevates in response to rain, runoff, etc. the pressure/stage level will increase.
This data is then paired with data collected at other sites and used to predict what might happen at the next bridge, culvert, pipe and/or road crossing downstream. Looking at the full picture, staff can see that when A happens upstream, B will happen also in about 15 minutes or 4 hours somewhere downstream. Knowing this, emergency management and public safety staff can, as mentioned above, respond in a timely manner with barricades and evacuation plans.
The most recent data shows that 96.89% of our flood warning sensors are fully functioning at the highest level of performance. Periodically, a sensor gets damaged, but out of 225, only 7 are currently offline. A map of sensor locations shows where they are distributed across the city.
But remember, in the end the flood warning system is only as good as the warnings we’ve built into it for the sites we have. Warnings are meant to help our community mobilize to respond to an emergency situation, but it is not a foolproof system. The flood warning system in place can assist in mitigating the losses experienced during a flood, but it and all of the public safety staff that support it, cannot win against Mother Nature in all places at all times. Do not EVER cross water over roads! If you end up in a flooded area, please call 911.
And because this is a post about emergency preparedness, it cannot go unsaid that you as an individual have a responsibility to have a plan of action in the event of a natural disaster or emergency. The Office of Emergency Management has plenty of resources to help you learn more about proper emergency preparation. Stay safe out there!