Farmers Branch stormwater engineer outlines floodplain, drainage and water-quality work

Eric Mueller, the city’s stormwater engineer, told the Farmers Branch Sustainability Committee that his office balances FEMA floodplain requirements, local drainage criteria, capital projects and stormwater-quality permits as part of a single program funded by the city’s stormwater utility.

Mueller said the city helps enforce FEMA floodplain maps so residents can participate in the National Flood Insurance Program. "If we didn't participate in that, then our citizens would not have access to flood insurance, which would be a very bad thing," he said. He described local drainage rules and a stormwater criteria manual used to size sewers, set detention requirements and guide capital improvements.

The nut graf: The presentation explained how the city pays for drainage projects through a stormwater utility fee, how billing is based on impervious area, and how compliance with state and federal permits drives water-quality work — framing why the committee’s interest in green infrastructure and public outreach matters to erosion, water quality and long-term costs.

Mueller said stormwater funding comes from a dedicated utility charge separate from the general fund and that residential billing uses three tiers based on impervious area. "We bill based off of impervious area," he said, and commercial properties are billed individually by impervious area. He described capital projects paid from that fund, including recent gabion-wall installations along Farmers Branch Creek and a culvert foundation replacement at Valley View at Rawhide Creek near City Hall.

On drainage capacity, Mueller said Farmers Branch has a Farmers Branch Creek master plan (final draft submitted about 2018) that has driven many creek projects. He described an upcoming project to upgrade the severely undersized storm sewer under Valley View Lane and an effort to start a master drainage plan for other parts of the city where deficiencies are known but not yet studied.

On stormwater quality, Mueller cited the Clean Water Act, the Texas Commission on Environmental Quality permit requirements and EPA standards as the basis for illicit-discharge elimination, construction-site controls and public-education obligations. He described response work after a recent call about a mysterious black substance on Tahoehorn and cited a mobile car‑wash event that left suds in the street as the kind of discharge the city investigates.

Mueller outlined green measures the city could pursue or encourage: vegetated or "green" bank stabilization instead of gray solutions such as gabion walls and concrete; more "grow zones" of native vegetation along creeks; incentives or mass‑order programs for rain barrels; and resident-installed green infrastructure such as rain gardens and redirecting downspouts to vegetated areas to slow runoff. He noted constraints including limited right-of-way, existing built environment and limited stormwater funds.

Committee members pressed for ways to quantify cost savings from resident action. Mueller said the direct dollar savings are difficult to quantify precisely but that preventing erosion and sedimentation can avoid expensive dredging and erosion repair projects that can cost millions. He agreed to explore existing studies—citing Austin and other jurisdictions as places that may have data—and to research grant opportunities and other funding sources.

Mueller also described routine enforcement tools: field inspections, citations and work orders for noncompliant construction sites, and public-education events required under the city’s permit. He invited committee participation in outreach and said a tabling event is planned next month.

Ending: Mueller provided contact information and the city stormwater web pages and the committee discussed follow-up ideas, such as pursuing rain‑barrel initiatives, testing how to better define allowed naturalized yards in code enforcement and adding an agenda item about code enforcement visuals. No formal action was taken on the presentation; it was received for information.