This chapter describes the background and methodology for integrating gauge and radar rainfall measurements into hydraulic and hydrologic modeling projects. Considering the importance of rainfall in modeling physical systems such as watersheds or sewer systems, attention to the accuracy, precision, spatial resolution, and processing protocol is essential for successful project completion. Using rain gauge network to adjust radar rainfall requires assessment of the rain gauge network and historical data that can help ensure accurate and reliable data. Radar is growing in acceptance in the management, monitoring, and design of sewer system improvements. Important aspects of how radar measures rainfall include understanding how measured reflectivity is converted to rainfall rates and then adjusted using rain gauges. Limitations and advantages of incorporating this data source depends on quality control and assurance procedures applied by project personnel and by the operators of the radar. The NEXRAD (WSR-880) radar deployed in the U.S. is a nationwide system that can be used in urban drainage system applications with appropriate postand real-time processing. Services are available that provide both real-time products useful in sewer system management and real-time control. Retrospective studies are possible for reconstructing events using radar data from multiple or single radar installations, and for which flow monitored data was collected. Comparison ofhydrographs produced using rain gauges versus radar reveals that radar is capable of producing accurate hydrographs. Calibrating hydraulic models to account for infiltration and inflow induced by rainfall is
The demand for large-scale watershed and sewershed planning studies in the United States has been increasing steadily over the past ten years. In large part, the demand is driven by major government programs regulating combined sewer overflows (CSO), sanitary sewer overflows (SSO), and storm water discharges. The implementation of these regulatory programs often results in local or regional public agencies embarking upon large multi-year studies requiring a comprehensive inventory of watershed and sewershed infrastructure, a characterization of the hydrologic and hydraulic function of that infrastructure, and analyses into the mechanisms by which pollutants are discharged into receiving waters. Significant monetary investments are made into comprehensive field investigations and surveys, hydrologic and hydraulic models, and regional facilities planning to develop and implement short-and long-term CSO and SSO control strategies.Accurately determining the quantity of extraneous flow that enters public sewers and private service laterals is a critical component of these comprehensive studies. The amount of rainfall dependent inflow and infiltration (RDII) entering the separate sewer systems varies from site to site and event to event as precipitation over a sewershed may produce different RDII responses within the sewers at different times of the year. The Lower Ohio hydrologic and hydraulic modeling project in Pittsburgh, Pennsylvania provided a unique opportunity to improve upon the accuracy and reliability of model simulations by incorporating monthly variations in sewer system responses to rainfall events. The completed analyses and model implementation were successful in quantifying site specific and seasonal variations observed in RDII responses.
The demand for large-scale watershed and sewershed planning studies in the United States has been increasing steadily over the past ten years. In large part, the demand is driven by major government programs regulating combined sewer overflows, sanitmy sewer overflows, and storm water discharges. The implementation of these regulatory programs often results in local or regional public agencies embarking upon large multi-year studies requiring a comprehensive inventory of watershed and sewershed infrastructure, a characterization ofthe hydrologic and hydraulic function ofthat infrastructure, and analyses of the water-polluting elements and processes. Significant monetary investments are being made into comprehensive field investigations and surveys, hydrologic and hydraulic models, and regional facilities planning to develop and implement short-and long-term combined sewer overflmv (CSO) and sanitary sewer overflow (SSO) control strategies. The amount and rate of rainfall and snowfall are the key driving force in the quantity of extraneous flow that enters public sewers and private service laterals and the frequency and duration of wastewater discharges into receiving water bodies. However, it is not uncommon to observe that disproportionately small investments are being made to improve the precision and accuracy of regional rainfall measurement. It has been demonstrated and documented in cities throughout the United States and around the world that calibrated radar-rainfall systems can provide accurate and precise rainfall measurement for large geographic areas. However, quantitative evaluations are relatively sparse that document whether
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.