Piloting Real Time Control Retrofits for Improved Hydromodification and Water Quality Control: Two Oregon Case Studies
Existing flood control and storm water quality infrastructure (e.g., detention basins, water quality basins) represent substantial historic investments in both land allocation and construction and maintenance costs. These existing facilities are increasingly being identified as opportunities for potential retrofit projects to improve or expand their functions for water quality and/or hydromodification control. However, the mandate to preserve the original function of the facility and/or work within the inherent limitations of the existing passive drainage infrastructure can often interfere with achieving the full potential of these retrofits. For example, when using passive outlet controls it can be challenging or impossible to maintain the original peak flow control function of a basin for large design storms while also improving flow duration control for more frequent storms.
Recent advances in information technology infrastructure as well as hardware systems and software solutions (known collectively as the “Internet of Things”) are providing inexpensive opportunities to achieve higher performance from stormwater controls by making real-time decisions about how to operate the control. Geosyntec has conducted pilot implementations of real-time control of distributed stormwater infrastructure across the country as part of a WERF research project. At its simplest, the approach involves aggregating information from on-site sensors (e.g., water level, flowrates), weather forecasts (e.g., probability of precipitation, quantitative precipitation forecast), and other potential information (e.g., streamflow data, precipitation data) and implementing custom logic based on these data to make automated decisions about when and how to store or release water. This type of improvement in function can often be achieved with minimal changes to the current physical infrastructure.
This presentation will highlight two current pilot projects using real-time control technology near Portland, Oregon. The first system involves retrofitting an existing stormwater pond to improve hydromodification performance for a 120-acre watershed. The project was completed in 2014 for a “fully loaded” cost of less than $1,000 per acre and is expected to substantially improve flow duration performance despite being undersized for its watershed area. Monitoring data will be presented to summarize observed performance to date. The second system will be installed on a detention basin in a new residential development (to be constructed in Summer 2014) to enhance the hydromodification control performance the basin, which was originally designed to provide flood control only (e.g., peak event matching). Both systems are also expected to achieve improvements in water quality performance compared to passive systems.
The presentation will discuss how actively managed systems may be able to help realize the full potential of stormwater retrofits in California watersheds, create new opportunities, and/or improve monitoring capabilities. It will also provide guidelines for identifying conditions that are favorable for consideration of active controls. We will also discuss the public outreach and education benefits associated with using modern online tools for stormwater management and monitoring.