Stormwater & Urban Drainage

Green infrastructure uses natural processes to manage stormwater, including rain gardens, bioswales, permeable pavements, green roofs, and infiltration basins. These systems reduce runoff volume, filter pollutants, and recharge groundwater. We model green infrastructure performance to optimize designs and demonstrate compliance with stormwater regulations.

Detention pond sizing involves modeling the entire drainage area to determine peak flows for various storm events, then designing storage volume and outlet structures to reduce peak discharge to pre-development levels. We use SWMM to simulate different storm scenarios and optimize pond geometry for both flood control and water quality treatment.

CSOs occur when combined sewers carrying both stormwater and sewage exceed capacity during heavy rain, causing untreated discharge to waterways. Solutions include separating sewers, increasing pipe capacity, adding storage tunnels, and implementing green infrastructure to reduce runoff. Our models help identify the most cost-effective combination of solutions.

Urban drainage modeling requires pipe network data (sizes, slopes, materials), catchment boundaries and imperviousness, topographic data, rainfall records, and flow monitoring data for calibration. We can work with GIS data, as-built drawings, and field surveys to build accurate models of your drainage system.

LID is a stormwater management approach that mimics natural hydrology by infiltrating, filtering, and storing runoff close to its source. LID practices include rain gardens, bioretention cells, permeable pavements, and green roofs. We model LID effectiveness to help developers meet stormwater requirements while minimizing traditional infrastructure costs.

Real-time control (RTC) uses sensors and automated gates/pumps to optimize drainage system performance during storms. Our models simulate RTC strategies to reduce flooding and CSOs by dynamically managing storage and flow. We help utilities design and optimize RTC systems for maximum benefit.

Urban flooding results from undersized drainage, increased imperviousness, blocked inlets, or extreme rainfall. Prevention strategies include upgrading pipe capacity, adding storage, implementing green infrastructure, and improving inlet maintenance. Our models identify the most cost-effective combination of solutions for your specific situation.

We simulate future scenarios by adjusting land use, imperviousness, and drainage infrastructure based on development plans. This helps identify where existing systems will be inadequate and what upgrades are needed. Proactive planning prevents costly retrofits and flooding problems as development occurs.

Detention ponds temporarily store stormwater and release it slowly, reducing peak flows but not total volume. Retention ponds permanently hold water, reducing both peak and volume through infiltration and evaporation. We design both types based on site conditions, regulatory requirements, and water quality objectives.

It has a supporting role, and it is mostly about the monitoring data. A short calibration campaign produces depth and flow series in which real hydraulic responses are mixed with silted sensors, blocked inlets and surcharge from a downstream connection nobody had on a drawing. An anomaly detection model is a faster and more consistent way of separating those than reading every trace by eye, and it is repeatable, which matters when a reviewer asks why a particular storm was excluded. Rainfall is the other half: daily gauge totals need disaggregating to the five-minute steps the model runs at, and imperviousness can be classified from imagery rather than inferred from a zoning map that is a decade old. The design storm simulation itself stays with SWMM, because a drainage system has to hold for a storm the city has not had yet.