A Real-Time Water Level Sensor Network and SWMM Model for the Design and Assessment of Low Impact Development Techniques

Large cities like New Orleans have embraced green infrastructure (GI) strategies to help absorb, delay, and treat stormwater to reduce flood risk and improve environmental resilience. The Gentilly Resilience District, for example, is the City’s first ever resilience district with a focus on projects that reduce flood risk, and support the area’s recovery and revitalization. With the University of New Orleans (UNO) Lakefront campus located within the area along the north shore of Lake Pontchartrain, it is an ideal location for this campus-wide case-study.

UNO investigators are developing a cost-effective network of water level sensors for real-time monitoring and calibration of a Stormwater Management Model (SWMM) for the campus and will implement this tool to study the effectiveness of GI systems. Currently, SWMM calibration for large-scale site-specific simulation is cost prohibitive because observed subsurface drainage flow data is needed in multiple locations during the same event. Investigators are testing an inexpensive unit that includes a microcontroller, Wi-Fi antennae, battery pack within a waterproof junction box and an adjustable linkage to a Maxbotix ultrasonic distance sensor mounted inside the manhole. It is installed simultaneously with a Teledyne area-velocity meter recording observed water level for data correlation to provide improvement in the ultrasonic sensor’s corresponding measurement estimates. The Wi-Fi antennae allows communication through the cloud-based IoT Thingspeak open data platform allowing real-time adjustment of sampling rate for an expected storm event and display of adjusted water level readings.

The SWMM model can be used to design/assess low impact development (LID) storage structures with respect to volume, peak flow, timing and provide comparison to required permitting of peaks and volumes for evaluating long-term impacts of LID structures. The development of this system will allow the designers to assess the condition of the stormwater drainage system and the efficiency of the LID alternatives.