Real-Time Storm Water Management Keeps Pace with Mother Nature

Managing stormwater is an increasingly challenging environment. Sea-level rise, increased frequency and intensity of storms, and continued urbanization mean that more and more people, property and critical infrastructure are subjected to the potential of flooding. With increased regulatory scrutiny being applied to stormwater management there is a growing need to understand the real-time operational conditions existing in this vital infrastructure. By understanding how stormwater systems respond in real-time, we can maximize the utility of the fitted infrastructure and wring every drop of capability and capacity out of it, saving significant capital investment. Storm water management is an increasingly challenging requirement. Sea-level rise, increased frequency and intensity of storms, and the continuing urbanization of our landscape mean more and more people, property and critical infrastructure are subjected to the potential of flooding. With increased flooding potentials comes an increase in the regulatory oversight afforded our stormwater management systems. In particular, combined and sanitary sewer overflows, non-point source pollution, and flooding abatement are driving a need to understand the real-time conditions of our stormwater management infrastructure. The problem is particularly acute in coastal regions where much of the developable land was originally natural wetlands. Municipalities designed and built during the 19th and 20th centuries in low lying regions like Florida used canals to drain and channel water to provide land on which to grow. While they were very successful in recovering the land, the result is that these canals and drainage systems are now critical to maintaining the economic prosperity of these communities. THE PROBLEM: INCREASING VOLATILITY The increasing volatility of the water cycle is resulting in more frequent and more intense flooding conditions — and these are becoming more difficult to predict and manage. This increase in stormwater volume and velocity is placing more pressure on municipal infrastructure, and by extension impacting municipal finances. Faced with an evolving threat, municipalities are staring down significant infrastructure costs and billion-dollar consent decrees to protect property and receiving waters. Despite these potential penalties and the prospect of massive water control projects, the benefits they may produce are decades in the making and consume billions of dollars of municipal revenue. It is imperative, then, that we begin to understand the real-time response of our currently fitted infrastructure such that we can maximize its utility in the provision of this vital service. Florida's Lake Worth Drainage District (LWDD) is a case study in maximizing the potential of fitted infrastructure. The LWDD encompasses approximately 200 square miles in southeastern Palm Beach County. LWDD was created in 1915 specifically for the purposes of draining, reclaiming, and irrigating the lands within its boundary and to provide water control and water supply to support the livelihood of communities along Florida's Atlantic Coast. Today, LWDD provides comprehensive flood control, water conservation and water supply protection for 13 municipalities serving more than 750,000 residents. As part of its mandate, LWDD monitors and controls a complex system of canals — nearly 500 miles in total length — 20 major water control structures and numerous minor structures across over 200 square miles — a daunting task given the potential for large storm events in the District. THE PLAN: ADAPTIVE STORMWATER MANAGEMENT In its 100-year existence, the practice of water control had been the same — keep the water moving. LWDD was not, however, adapted to the new reality of stormwater. In preparing the District to meet the needs of the 21st century, staff was hampered by infrastructure mired in an 18th century operational philosophy. While the District had installed a SCADA system to control flood gates and other infrastructure there was a lack of real-time knowledge about what was happening in their canals, upstream of the District and downstream of their system — critical information to know when moving water. The District lacked a system-wide view of the condition of their canal network, requiring the staff to be on the road continually checking that status of the District's infrastructure and attempting to prepare for upcoming events. Often, the process involved driving to a canal staff gauge, reporting the condition, making an operational decision, driving to the control gate to implement the control decision, then driving back to the original point to check the results. It was often a two-hour exercise to implement one decision — in an era where events were changing by the minute. Additionally, the District lacked an integrated view into the current and projected meteorological conditions (like radar and rainfall intensity) and real-time level information from adjacent systems upstream and downstream of the District. As a result, operators found themselves continuously in a reactive mode, struggling to react quickly enough to protect their customers. LWDD's vision was to replace the human-centric decision and reaction system, with one based on data, information and control. The District's solution was to acquire and deploy SmartCover real-time flow monitoring devices using satellite communication to constantly communicate the dynamic conditions within the District's flood control infrastructure. Level sensors feed the SmartCover platform which integrates with National Oceanic and Atmospheric Administration (NOAA) rainfall information, regional radar data and tidal information and works in conjunction with the District's remote-control SCADA system for gate operation. This architecture has revolutionized the District's response time, allowing changes in conditions to be monitored in near real-time, while reducing the uncertainty around the conditions in the flood control network. Importantly, the SmartCover system has proven to be invaluable in identifying those conditions that could result in both anomalous readings and could restrict system performance. Identifying in real-time when canals need to be cleaned has been a corollary benefit of the SmartCover installation. Overall, the District has noted a high degree of precision in the readings and Doppler integration. This has given the operations team a level of confidence in decisions and enabled them to quickly move water out of the system and lower the probability of flooding and reduce operational response time to minutes as opposed to hours. With a real-time view into the dynamics of the system, LWDD can make adaptive decisions in advance of storm events. In this balance, it is important that actions reflect real potential as lowering canals and reservoirs can result in water supply issues should the storm event not impact the region. THE PROOF: IMMEDIATE PROTECTION This system was put to the test during Hurricane Irma in September 2017. Hurricane Irma was an extremely powerful hurricane, which brought devastating winds and flooding to a large swath of the eastern Caribbean and the eastern US seaboard. Irma was the strongest storm on record to exist in the open Atlantic region and the national Hurricane Center observed that the combined effect of storm surge and the tide produced maximum inundation levels of 4 to 6 ft above ground level for portions of Miami-Dade County in southeastern Florida. With the integrated system giving combined visibility on the canal status as well as rainfall intensity and duration, the District was able to predict the performance of its flow control infrastructure, project peak stages and make educated, proactive decisions on managing this historic event. This adaptive stormwater system allowed the District to operate with no interruption in service before, during, or after Irma. THE PAYBACK: EFFICIENCY Using SmartCover's strategic sensor placement process, the District was able to maximize the impact while minimizing costs, resulting in a 2-year payback simply in reduced manpower costs. That benefit is independent of the operational efficiencies in maximizing the capacity within the District's built infrastructure, reducing the requirement for capital improvements, and preventing property losses. Overall, LWDD has deployed 11 sensor field units throughout its canal network. The deployment provided an immediate economic benefit by reducing the manpower requirements to read staff gauges and respond to events. Real-time information and control have also dramatically reduced overtime costs. In developing the business case, the District estimated the payback on the investment in SmartCover in the order of two years. With the new platform, LWDD is realizing additional benefits such as understanding how to prepare flood control networks for upcoming storms.