Taking Stormwater Real Time Controls to the Watershed Scale: Evaluating the Business Case and Developing an Implementation Roadmap for an Oregon MS4
With increasingly stringent MS4 Permit requirements and other watershed management challenges, the need to attain higher performance from existing and future stormwater management facilities has never been greater. Clean Water Services (District), an Oregon MS4 permittee, is evaluating the use of real time control of stormwater facilities as part of is long term strategy for stormwater management, specifically as an approach to help improve hydromodification control and water quality performance of existing facilities and improve the efficiency and adaptability of future facilities.
In 2013 and 2014, two full scale pilot projects of real time controls were completed for retrofit and new development applications to improve hydromodification control and water quality performance while preserving the original flood control purposes of the facilities. Based on the initial successes of these pilots, the District has explored additional opportunities for retrofit projects, and evaluated the cost and benefits of this approach (i.e., the “business case”). This evaluation included:
(1) Retrospective analysis of performance data and lessons learned from the existing pilot projects (i.e., how well are the current systems performing and how can this be further improved?)
(2) Identification and prioritization of opportunities for additional real time control retrofits, including a District-wide GIS-based screening of existing stormwater assets and future proposed development areas (i.e., how many potential opportunities are there for real time control-based projects?)
(3) Modeling case studies of the benefits of real time controls at the scale of individual facilities, and for multiple facilities networked within a subwatershed (i.e., what improvements in level of service could be achieved via broader implementation of retrofit projects, particularly if systems could “talk” to each other at a watershed scale and incorporate watershed data such as streamflow in making automated operation decisions?)
(4) Modeling case studies of flow duration control design for land development (i.e., how much smaller could flow duration control BMPs be made for new development and redevelopment projects with the use of real time control?)
(5) Cost implications of real time control approaches.
The District is also developing a long term strategy or “roadmap” for broader implementation of real time controls, including integration with existing monitoring and information technology systems, installation methods, system operations and adaptations to maintain and improve performance, facility operations and maintenance, integration with flooding emergency response, and project phasing. District IT staff, maintenance personnel, capital improvement engineers, and system operators have contributed to this effort. The results of this planning effort will also help prioritize enhancements to the online platform that supports the current pilot projects.
This presentation will include: (1) lessons learned from pilot project implementations, (2) highlights of data analysis and modeling case studies, (3) findings from the evaluation of potential opportunities, and (4) highlights of the District’s implementation roadmap. The findings from this effort are expected to be transferrable to California and Western US permittees and stormwater designers who are considering real time control strategies and whom face significant hydromodification control requirements.