Active Hydromodification Control

Date / Time:
Wednesday, Oct 21 11:30am to 12:00pm
Big Sur
Track / Session:
Stormwater Treatment / BMPs and Urban Streams

The state of the practice for hydromodification management for new development is to mimic long-term pre-development site hydrology. The theory is that if the pre-development distribution of in-stream flows is maintained, then the baseline capacity to transport sediment, a proxy for the geomorphic condition, will be maintained as well. A popular method of mimicking the pre-development flow regime is via flow duration control (FDC) which can be achieved by routing post-development runoff through structural stormwater BMPs such that runoff is stored and slowly released to match pre-development flow rates and durations. Storage requirements for FDC tend to be much larger than that for surface water treatment requirements, particularly when the BMPs are small, distributed LID facilities with simple outlet structures.

This presentation describes a recently invented methodology for active stormwater controls to optimize sizing and design of Hydromodification Control BMPs to achieve FDC. An actively controlled BMP outlet consists of a modulating valve, orifice, or pump in place of a passive stagnant orifice. With the use of active stormwater controls and the methodology described, benefits are three-fold. First, new BMPs can be optimized to be smaller and, thus, more feasible to implement. Second, existing stormwater facilities designed for flood control or other management objectives can be retrofitted to provide hydromodification control. Third, when utilized with real-time flow and water level monitoring equipment and data, the flow release logic can be adaptively adjusted based on calibrated data without physical retrofit of the BMP’s outlet.

Primary Speaker:
Judd Goodman, Geosyntec Consultants
Mr. Goodman is a Water Resources Engineer with ten years of experience in planning, design, and adaptive management of surface and potable water systems. Judd’s professional passion lies in providing flood and erosion protection for the public while preserving natural riparian and earth processes. With Geosyntec Consultants, his most significant technical contributions have been made solving surface water problems, which require both an engineering and geomorphic perspective. Mr. Goodman has been involved in a variety of projects including hydromodification planning and impact analysis, stream channel rehabilitation design, geomorphic field assessment and monitoring, erosion and sediment control inspection, design of stormwater management systems, and storm event characterization for litigation support. Project contributions have included project management, hydrologic modeling, hydraulic calculations, sediment budget and transport analysis, geographic data analysis, historical document review, and field reconnaissance.