When It Rains, It Pours and What Does the Rain Do to the Drainage Ways in Nacogdoches
“If the good Lord is willing and the creek don’t rise,” is a common adage in these parts, but the City of Nacogdoches public works department can’t use the creek rising as an excuse. At the end of 2018, the creek literally rose with our community receiving two feet of precipitation beyond our normal annual rainfall amount of 49 inches. While this maybe just a drop in the ocean to some, it can certainly be problematic for the City of Nacogdoches facilities as rainwater makes its way to the final destination. These hard rains translate to several trillion gallons of extra storm water which had to find its way through our yards, streets, and creeks to ultimately end up in the Gulf of Mexico.
Overloaded creeks and streets can flood our property, erode soil in our yards, and stop progress on building projects and numerous outdoor activities. Managing an excess of storm water is a challenging and sometimes futile exercise for both property owners and City staff alike.
Drainage is influenced by the slope of the land, soil type, vegetation, and changes in ground cover. As Nacogdoches continues to grow, development brings new pavements and buildings which increase the runoff. This additional water can eventually overload our creeks, streets, and storm drains.
Our City’s topography generally confines most of our flooding to areas along our two main waterways, Lanana Bayou and Banita Creek, and most modern-day drainage concerns are related to development within the flood plain zones which are typically situated within 1,000 feet or less from either waterway. While other areas away from the creeks may also experience flooding due to poor localized drainage problems, the flooding can often be cured with minor construction.
In order to mitigate these challenges, the City of Nacogdoches adopted a Drainage Ordinance in 1992, which outlined minimum design standards for projects and defined the conditions when a new development would need to construct on-site storm water detention ponds. These ponds temporarily hold excess runoff from a storm and slowly release it back into the natural drainage systems at a rate similar to before the land was developed. Many of these storage areas are incorporated into parking lots or shallow earthen ponds.
Our development ordinances and permitting processes help control how and where buildings are built so that they are above the predicted 100 year storm flood level. Interestingly, the so-called 100 year storm is not an event that happens once every 100 years, but actually refers to the probability of a theoretical storm that has a 1% chance (1 chance in a hundred) of happening in any given year. The “100 year storm” for Nacogdoches is commonly defined as 11.3 inches of rain over a 24 hour period.
Steve Bartlett is the City of Nacogdoches Engineer. He began working in this role in 2015. Prior to this, he served as a consultant for the #cityofnac while also operating his private eningeering firm in Nacogdoches, BarWin Consultants.
Steve has three children and four grandchildren. He enjoys hunting, fishing, and being bossed around by his wife, Cheryl.