Beyond Flooding: Why Drainage Drives Municipal Decision-Making

Introduction:

Ashleigh Scott is a Civil Project Manager in RLG’s Fort Worth office with almost 10 years of experience supporting municipal infrastructure projects across North Texas. Her work includes civil engineering design and coordination for roadway, drainage, utility, and site development improvements, working closely with public sector clients to help deliver practical solutions that support growing communities.

Effective drainage systems are a critical part of municipal infrastructure, helping cities manage flooding, protect roadways, and support long-term growth. But for municipalities, stormwater management and drainage planning are often some of the earliest and most important considerations in a project. From flooding concerns and aging infrastructure to future development and roadway impacts, drainage plays a major role in how cities plan, prioritize, and design public improvements.

We spoke with Ashleigh Scott about why drainage is such a critical part of municipal engineering and what cities are paying closer attention to today.

 

---

Why does drainage become such an early focus for cities when planning infrastructure projects?

"Drainage is a critical topic of discussion for municipalities because it affects all other aspects of an infrastructure or development project. If stormwater management is not evaluated or addressed early in the design process, cities risk having to redesign streets, utilities, and even entire developments later to address drainage deficiencies.

From a municipal design perspective, stormwater considerations primarily affect roadway grading and utility alignments. Roadway profiles must be designed to promote positive drainage and avoid adverse impacts on adjacent properties, including those downstream of the project limits. Proposed utility alignments must also coordinate with existing or proposed storm drain infrastructure to avoid conflicts, maintain functionality, and maximize cost effectiveness."

What are some of the most common drainage challenges cities are dealing with right now?

"As city populations expand, infrastructure becomes outdated and unable to accommodate increased demand. New development and increased impermeable surface areas generate more stormwater runoff, requiring storm infrastructure to handle greater flow volumes.

With rapid growth, like what North Texas has experienced over the last few decades, cities are struggling to keep pace with the infrastructure improvements needed to support said growth. At the same time, municipalities are experiencing more frequent and intense storm events, increasing the need for resilient stormwater systems.

While FEMA floodplain maps identify flood risk along waterways, they do not capture every area that experiences flooding. Municipalities are beginning to take matters into their own hands. The City of Fort Worth, along with other cities in North Texas and across the country, has begun mapping Non-FEMA Flood Risk Areas where flooding is known to occur outside federally mapped hazard zones. Cities are increasingly requiring additional stormwater management measures in these areas for new developments, even when FEMA regulations would not otherwise apply."

How does drainage planning affect other parts of a project like roadways, utilities, or site development?

"Improving roadways in developed areas is different from roadway design on undeveloped land. Our goal is to improve drainage conditions for property owners within the project area. This can range from correcting small low points in roadways where standing water collects, often called bird baths, to designing storm drain infrastructure, including pipes, inlets, and culverts.

For the City of Fort Worth's Bond Year 2, Contract 9 Water, Sanitary Sewer, and Paving Improvements project, although storm drain infrastructure design was not included in the project scope, full paving improvements, which include curb & gutter, required positive drainage to be maintained throughout the corridor while not disrupting existing drainage patterns. All runoff within the public right of way was required to drain toward the street rather than toward adjacent properties. In areas without existing curb and gutter, this often required lowering the roadway profile to ensure the right-of-way elevation remained above the top of the curb elevation. To achieve proper drainage while tying into existing conditions, split curbs with different elevations on each side of the roadway were sometimes necessary.

On the City of Dallas Corinth Street Improvements project, RLG designed a storm drain system that connected to an existing culvert to convey runoff collected along the corridor from within and beyond the project limits. Inlet locations were coordinated with the proposed roadway profile to maintain positive drainage, while drainage area analysis and inlet calculations were performed to determine the required inlet and pipe sizes."

What is one thing people often misunderstand about drainage or stormwater infrastructure?

"Many people only notice drainage infrastructure when flooding occurs, but effective stormwater systems are designed to prevent problems before they happen. A significant amount of planning, analysis, and coordination goes into designing systems that safely convey stormwater while protecting roadways, utilities, businesses, and homes. When drainage infrastructure is working properly, most people never have to think about it."

How can cities benefit from addressing drainage concerns early instead of later in the project process?

"Addressing drainage early helps municipalities make better decisions throughout the design process. It reduces the likelihood of costly redesigns, minimizes conflicts with utilities and roadway improvements, and helps identify potential flooding concerns before construction begins. Early planning also allows cities to prioritize infrastructure investments more effectively and develop solutions that will continue to serve the community as it grows."