Important engineering decisions are made every day regarding sanitary sewer, combined sewer and storm sewer systems, and they often require the use of rainfall data. Although these decisions involve significant capital investment and expenditures to protect public health and the environment, the integrity of the rainfall measurements that support them is often overlooked. Kevin Enfinger, P.E., has examined guidance from a variety of professional organizations in engineering, water resources and meteorological fields and has consolidated his findings into a concise, flexible approach to obtain appropriate rainfall data to support sound engineering evaluations and decisions related to the urban sewer environment. This approach will be discussed in a two-part series.
Part 1: Successful Planning
Selecting rainfall monitor technologies and products suitable to support sewer system design and evaluation prompts two questions: What accuracy is required, and over what rainfall intensity range? Answering these questions provides insight into which technologies are most appropriate and provides a means to evaluate which products can deliver the desired results. Once suitable equipment has been selected, consideration should be given to the number of rainfall monitors required. Rainfall monitors measure rainfall at discrete locations. Therefore, multiple rainfall monitors are required to estimate rainfall variation across larger geographic areas. Technical recommendations from several professional organizations are discussed to estimate the number of rainfall monitors required and determine their preliminary locations.
Kevin Enfinger, P.E., is a product manager at ADS Environmental Services with 25 years’ experience in environmental engineering and consulting. He has worked as a project manager, project engineer, region engineer and product manager at ADS. Enfinger is a registered professional engineer in six states and is a member of the American Society of Civil Engineers and the Water Environment Federation. He has authored numerous technical papers and given various presentations through these organizations to advance the science of wastewater collections systems evaluation.
