Introduction

Abstract

Countries and organizations around the world are working to reduce stormwater runoff volumes and increase the quality of runoff before it enters receiving water bodies. These efforts have resulted in the development of stormwater treatment practices, designed to retain contaminants such as suspended solids, nutrients, bacteria, metals, and others. The stormwater treatment practices are designed to perform at a certain level of treatment, but, over time, the performance level will decline due to factors such as clogging with sediment, reaching some finite contaminant storage capacity, excessive vegetative growth, and a host of other factors. Stormwater treatment practices must receive intentional and regular maintenance to perform at predetermined, desired levels of runoff volume reduction, contaminant load reduction, or other primary objective over an extended period of time. In order to perform cost-effective maintenance at optimal time intervals, the practice must be regularly assessed. Assessment, as defined in this book, is the determination of the level of performance of a stormwater treatment practice with regard to the treatment goals of the practice and/or the determination of the state of a stormwater practice. For example, the former may include determining the percent load reduction a practice obtains with regard to suspended solids, while the latter may involve inspecting inlet and outlet structures of a pond for structural integrity and potential blockage from trash and debris. Only after a practice is assessed can optimal maintenance actions be planned and performed. This chapter presents three levels of assessment, including visual inspection, testing (including capacity and synthetic runoff testing), and monitoring. The levels increase in complexity as presented and should be used selectively in accordance with stormwater management goals.