Misconceptions of the 100-year Flood



The recent flooding of Indian Creek that led to the damage and closing of Coach’s Bar and Grill has brought much attention from local papers and news stations. Several local media outlets have presented the flood as a “100 year flood event.” But what makes a flood a “100 year flood”?

Due to the nomenclature of the 100-year flood, many are often confused as to the likelihood of such an event happening, and, as a consequence, may under prepare or under insure with the illusion that a flood of this magnitude is a once-in-a-lifetime event. A 100-year flood event should statistically happen once every 100 years over a long time period, or have just a 1 percent chance of occurring within any given year. When people hear that a 100-year flood has occurred on a particular river, they may incorrectly assume that a flood of that magnitude should not happen again for roughly another 100 years. This is the same logical fallacy that would lead one to believe that flipping a coin and it coming up heads four times in a row is far more unlikely that flipping alternating heads and tails four times (statistically speaking, each are equally likely). Probabilities of this time scale should only be applied over long time horizons and cannot be accurately applied to short time periods. Therefore, back-to-back rare events may be more common than one would originally believe.

In addition to misinterpreting the definition a 100-year flood, there are a few other issues that can lead to error in attempting to predict such an event.

First, there is a common misconception that a 100-year storm event will always lead to a 100-year flood. While the classification of a storm event will affect the significance of a flood, many other factors contribute to a river’s flood levels, such as the current soil saturation or the coverage of a particular storm within a watershed. For example, a 100- year storm may only affect a small portion of a dry watershed area, thus only leading to a downstream river reaching 20 year or a 50 year flood levels. On the other hand, a less intense rain event on top of fully saturated soil may lead to more significant flooding.

Second, a 100-year flood event is only an approximation based on past data and is no guarantee of future outcomes. Because of the uncommon distribution of flood levels, there is no significant correlation with any common mathematical distribution to accurately estimate the actual probabilities of flood events. Whereas a human’s height or test scores can be normally distributed and graphically represented with a bell curve, the distribution of flood events cannot. Although the U.S. government has stated that flood events should be estimated using a Log Pearson Type III distribution, this distribution is by no means a perfect way to accurately predict flood events and must be used with caution.

Finally, it must be noted that the 100-year flood level is dynamic and can be reduced with good engineering. The probability of the 100-year flood level being reached within any given year is estimated at 1 percent. Because peak river levels are largely affected by increased runoff, an increase in urbanization and development may lead to an increase in the 100- year flood levels downstream, putting more homes and businesses at risk for flooding. However, through the use of detention basins or retention ponds and technologies like permeable pavements, runoff quantities can be reduced and subsequently lead to lower river levels during 100-year flood events.

In conclusion, extra caution must be taken when designing for low probability events, such as the frequency or level of a 100 year flood, regardless of how unlikely the event may seem at first glance. Through the intelligent use of detention and retention systems, the impact and loss of major flood events can be decreased for all homes and businesses downstream of urbanized areas.

– Derrick Price, Project Engineer

Keeping the Flood Waters Away

W above Indian Creek on Holmes

The recent flash flooding of Indian Creek in South Kansas City resulted in major repercussions for homes and businesses near the creek. Storm watch rain gauges located near Holmes Road and 103rd Street in Kansas City  indicated an average of 4.69 inches of rain over a 24 hour period. The highest intensity of rainfall fell between 2AM and 5AM on July 27, 2017, totaling 3.8 inches in just that narrow three-hour window.

Several of the restaurants and businesses that run the span of 103rd Street between State Line and Wornall roads were inundated with water. We at TREKK are saddened by the damages and losses to businesses along 103rd Street, including Coach’s Bar & Grill, which has been in business for more than 34 years.

As a GIS specialist at TREKK, my focus is primarily on water and wastewater data collection and management. Events like this flood remind me why I, along with my team of amazing field personnel and fellow office staff members, work every day to help manage these problems.

Why am I so passionate about this issue?

Storm water is the leading cause of pollution to our communities. While this may seem like a significant problem only when the wet weather event is actively creating chaos, the damage will far out-live the receding waters. When flooding occurs, pollutants like the oil from vehicles, chemicals and solid deposits gather and get distributed into the waterways. These events are devastating to the aquatic life and animals that rely on these waterways. A wet weather event like this and even those with far less intensity can cause problems, such as sanitary sewer overflows into streams and creeks, as well as backups into basements.

Sanitary sewers are designed to handle domestic wastewater flows from buildings and become overloaded during these extreme rain events when excessive storm water leaks into the system. Excessive flows enter the system through defects like cracks or offset joints in the pipes and through illicit connections on private property.  When the pipe has reached full capacity, the polluted water overflows wherever there is a path of least resistance.

Local governments spend an exuberant amount of money trying to rectify the damages to both private and public property caused by flooding. It is the efforts of the government, community and the people who are passionate about water/wastewater management that create and maintain a sustainable system with the hopes that flooding can be reduced or eliminated.

– Joann Smith, GIS Analyst

With the help of Officer Kaiser of the KCMO Traffic Unit, Joann took these photos at 8:15AM, nearly three hours after the conclusion of the rain event at the Indian Creek and Holmes Road intersection. 

E above Indian Creek at Holmes N toward Indian Creek Bridge on Holmes 2 NW above Indian Creek on HolmesE above Indian Creek at Holmes 2

Delving Into Data Delivery

Delving Into Data Delivery

For our Springfield Office, 2017 is easily our biggest year for flow monitoring to date. Across seven projects, we have upwards of 70 meters in the ground and more than 20 rain gauges across southwest Missouri. TREKK’s field crews work diligently to interrogate and maintain our monitoring equipment and bring in large volumes of data. Our technicians, project managers, and clients are excited to see the data and the story that it tells.

We are often so focused on the final product, however, that we forget the journey the data goes through to be presentable to our clients.

During our first week of flow monitoring, I asked a coworker if I could help with some of the flow monitoring data. I was tasked with formatting data that would be imported into our analyzing software. We could easily spend two or three minutes formatting each file, and I realized we could save time and frustration by automating this process. This led me to start exploring Microsoft Excel macros and I was quickly able to reduce the formatting step to the click of a button. This first step grew into developing three new tools that automate, process and detect errors in the data that we collect.

Upon reflection, I realized that our motto of IMPROVING LIVES has many different applications. By working together with my coworkers, we were able to refine our process and make the job easier by eliminating some of the tedious time spent formatting and processing data. This allows for our technicians to streamline data processing and deliver quality information quickly and accurately to our project managers and to our clients. It is another way that TREKK is IMPROVING LIVES.

-Ralph Hill, Engineering Technician

It’s Not Goodbye, It’s See You Later

It’s Not Goodbye, It’s See You Later

It is rewarding, but it sometimes can be difficult to accept what IMPROVING LIVES means.  Last Monday, May 8th, Courtney walked into my office and told me the news that she was leaving to take a job with the U.S. Army Corps of Engineers.  The best word I can use to describe how I felt is heartbreak.  Many of you may not know, but Courtney is like a daughter to me.  I met her at my first job out of college.  I was working for the Missouri Department of Transportation as a Highway Designer.  Courtney’s mom, Amy Nash (Barry’s wife) was one of my first mentors.  Amy was a brilliant mentor without really ever trying to be.  She helped me to learn to think for myself, design with common sense and listen to my instincts.  She was one of the first in my professional career to help me understand the importance of IMPROVING LIVES.   Looking back, I realize that I was one of Amy’s first work “sons.”  Courtney was raised by parents that always wanted see people do their best.

When we met, Courtney was around the age of 5, so Kim and I have known her practically all her life.  We have gotten the opportunity to watch her grow from a young girl into a brilliant engineer.  Courtney has been one of our favorite examples of the value of internship program at TREKK.  She worked her way through survey, design, and construction inspection.  She benefited from seeing all the aspects of a project.  The opportunity to see our projects from multiple perspectives has helped her hone her design engineering skills.

I was sitting down with Linda discussing how I personally felt hurt about Courtney’s decision to leave.  Linda understands the back history of our relationship, and she did an amazing thing for me during that conversation.  She told me a story about a sermon she had heard from her pastor who would invite other pastors to come in share their stories.  Sometimes, his church members would leave to attend church at the guest pastor’s congregations.  Now, the pastor didn’t intend or want to lose any members, but as part of their life path, they moved on.  The pastor realized that even though members left, they took with them the foundation and beliefs that they had developed together.

Linda pointed out all the ways that TREKK improved Courtney’s life.  TREKK gave her a place to develop as an engineer and a person.  We taught her a profession, provided mentoring, guidance, and training.  We saw her through apartment moves, getting engaged, married, and buying a home.  We provided her a place where she could flourish as who she is.  She is happy at TREKK.  She understood that IMPROVING LIVES was not just a saying, but rather a mindset – a way of living your life.

I then thought about how Courtney improved our lives.  She is a great engineer. She can figure out just about anything that is assigned to her.  We laugh thinking about how she taught herself ARC GIS by watching YouTube videos.  She is not afraid to just dig in and figure things out.  Courtney shares her passion about engineering with all of us.  When asked to help lead a class with Young Women in Engineering or Take Your Child to Work Day, she was full go.  She is quick with a witty remark or rubber band.  She can make you smile with just her little grin.  She always makes us proud.

So, it was heartbreaking to hear her say she wanted to leave.  But, she wants to understand what the public sector is like, and this is understandable because her mom has spent her whole career in the public sector.  She saw how to have a family and a career by watching her mom, so it is only natural that she explore a familiar path as she considers beginning her a family of her own.

I would offer a different perspective.  IMPROVING LIVES at TREKK is not just about our clients, it is about our people as well.  We make every decision with the good of TREKK in mind.  TREKK at its purest form is nothing more than the people who work here.  That results in us making decisions for the good of our people.  We believe that sometimes as individuals our perception skews the reality of our situations, and at those times we need help to discover our true reality just as Linda helped me.  Our intention is to make sure that at TREKK, we IMPROVE LIVES internally and externally.  We want to make your work align with your personal goals, and we will do all within our ability to make that alignment possible.  We want you to describe your job as awesome.  We want to help you achieve personal and professional happiness here at TREKK.

We believe that our culture aligns with Courtney.  She will continue to IMPROVE LIVES beyond the confines of TREKK, because she believes as we do, in making the world a better place by IMPROVING the LIVES of those who are around us every day.  Maybe, just maybe, her life’s path will bring us back together at TREKK because we believe in good people, and that good people like to be surrounded by like-minded, good people.  So if you look up some day and she is sitting beside you, don’t be surprised.  Just remember that each of us at TREKK is committed to IMPROVING LIVES because it is our way of life.

– Trent Robinett

What We Did at Daddy’s Work

What We Did at Daddy’s Work

On April 27, TREKK celebrated Take Your Child to Work Day. Thanks to our guest bloggers for sharing their experiences!


What we did at Daddy’s work. One day there lived two girls and one boy. One of the girls was named Emery, the other girl was named Johanna and the boy was daddy. First we went to look at the sewers and Alex went inside the building and put green dye in the toilet and flushed it also he turned on the sink. We looked at the smoke generator. Next we sole the drone. We went inside and Trent showed us around the offices and we saw the world’s biggest printer. Then we made candy bridges out of gum drops. It was fun. And when we were done with making our candy bridges, Trent showed us a real life bridge it awesome and it was also fun too.  – Emery Smith 


Today was a great day because it was bring your child to work day and it was so fun. First me and my little sister were a little shy, but we saw people we knew and talked and we were not shy anymore. Second we looked around the offices, made name tags and ate donut holes.  Trent told us what we were going to do. Third Lucas took us outside and showed us the sewer and he opened it and Alex went inside the building and flushed the toilet and added green dye in the toilet and turned on the faucet and we looked inside the sewer and we saw the green dyed water! It was gross and pretty cool.

Next we went over to the smoke generator. Tim pulled the pull cord and smoke came out of the storm sewer inlets, and it was stinky because the air was filled with smoke! Next Trent showed us a robot that was cool too. If we stood in front of the camera you could see yourself on a screen in the truck, it was so awesome. Sixth we saw the drone and Alex drove it around really high in the air and then Alex landed it. He was really good at flying it around and landing it.

Seventh we went inside dads work.  Finally.  That stuff was cool but also the weather was really cold too, Burr! Eighth I played hide and seek with some other kids at the place. It was fun but we only got to play for one round because we had to do the next thing. Ninth Trent showed us around the offices and showed us a really gigantic printer. Tenth he led us to Derek’s office and he showed us a 2D and a 3D bridge on his computer.

Eleventh we got to make gumdrop and tooth pick “bridges” and after we built them we tested them and saw how much they could hold. Me and Emery’s held almost 2 pounds but it flipped over and the books fell off.  I was disappointed. Twelfth we played more hide and seek and then we tried to improve our towers but we didn’t really test it again though.

Thirteenth Trent said that we were going to see a real bridge but I wanted to keep “improving” my bridge, so me and Emery stayed at the work. Emery went to dad’s office and colored on paper (of course). But I played 3D tic-tac-toe with Courtney then I looked around more and waited, waited, waited and waited. The pizza got here and I realized that we had extra name tags and said ”Hello my name is pepperoni” because the name tags said Hello my name is ______ .  Courtney said “Hey! That’s a great idea” so I wrote on name tags pepperoni, supreme, sausage and cheese.  We waited and waited some more. They were finally back from the bridge so we ate lunch. The pizza was so good! After we ate pizza we made our own “roads” and I put milk duds, chocolate pudding, crushed Oreo’s and chocolate chips in mine. It was so delicious and I can’t believe Emery didn’t eat all of hers. After that we played around and then we had to leave so I found Emery and we got our certificate and left.

Today I was mostly happy because it was bring your child to work day, but there were times when I wasn’t that happy like when Emery started taking apart the bridge and eating all the gumdrops! Another reason is when I had to leave I didn’t want to go but I also did because I wanted to see what we were going to be doing at moms work too. But I always love when this day comes! I am so excited when this day will come next year and I think this is a great place to work especially my dad because the people that work here are kind, hardworking and always willing to take a challenge that’s why me and my dad and even more people love TREKK!  –Johanna Smith


Thank you for giving us an opportunity to experience the life of an engineer. It was fun when we learned smoke testing, the tools to clean a manhole, mapping out the state of Missouri, and most of all eating are roads that we made. I also liked when we made are bridges. TREKK is a really fun place, and I love when we go there. We will see you again. Thank you! –Andsew Yibekal, 4th grade


Take your children to work day at TREKK was very fun. We did smoke testing. We also put green dye in the toilet and flushed it. We saw it flow through the sewer. We saw the leaves from the storm sewer being vacumed with a massive vacume. They controlled a robot. They said it goes down the manhole. They also flew a drone to see the smoke, after the smoke testing. We learned about the street light. We saw 2 projects that people were working on. They explained it to us. We located citys on a huge Mizzouri map. We built bridges with toothpicks and gummy dots. We walked on a trail and saw a real bridge. We ate pizza. We learned about the roads then we made our own road with desserts. Everything was very fun. –Aderajew Yibekal, 5th Grader