STRUCTURAL BMP/SUDS MAINTENANCE – ACTIVITIES AND ASSOCIATED COSTS

This paper presents the results of the maintenance assessment aspects of a major stormwater research program undertaken in both the United States and the United Kingdom. The primary source of maintenance information was derived from facility inspections, monitoring, and direct interviews with stormwater agency and unitary authority personnel together with other operators and experts in the US and UK. The most detailed information was obtained for the most commonly used systems: retention ponds, extended detention basins, and vegetated swales. This maintenance assessment sought to:Gather comparative maintenance data and information from the U.S. and UK.Define the maintenance inputs (tasks, person-hours, equipment, etc.) and frequencies required to keep structural controls functioning and avoid failure.Define the tasks which give aesthetic benefits (non-essential to function) as opposed to functional benefits (performance or public health failure).Obtain information to derive costs and provide information for a Whole Life Cost Model which was being developed as a separate strand of the project.Evaluate possible variation of maintenance requirements by climate or geography.Identify designs that will reduce maintenance costs and inputs.A wide variety of maintenance practices and preferences were noted over the many agencies and organizations interviewed for this project across two nations. Detailed maintenance tasks and respective costs were estimated for each of the six system types. The basis for the estimations is presented and explained, especially where data is limited or varies. Maintenance data were collected and organized specifically for inclusion in the Whole Life Cost model.This paper summarizes the findings and conclusions of a three-year international stormwater research study funded by the Water Environment Research Foundation (WERF), United Kingdom Water Industry Research (UKWIR), and the American Water Works Association Research Foundation (AwwRF). The project team was directed by Black & Veatch Corporation and its subsidiary in the United Kingdom (UK), Black & Veatch Consulting, Ltd. Project team members included H.R. Wallingford, UK; the Urban Water Technology Centre, Abertay University, Dundee, Scotland; Center for Research in Water Resources, University of Texas at Austin; and Glenrose Engineering, Inc., Austin, Texas. The project was managed by WERF as project 01-CTS-21T.