Constructed wetlands have gained acceptance as a means of treating stormwater runoff from urban developments. Much of the available data regarding the performance of these facilities is based upon monitoring conducted over the course of less than two years, and as such inherently assumes that the period of analysis represents the “typical” or “design” conditions under which these facilities are intended to operate. While this information has provided guidance regarding the mechanisms by which wetlands provide quality treatment of urban runoff, it does not fully reflect the variability of conditions under which the facilities operate over the fullness of time, which is of particular concern to designers and operators. The construction of the Dartnall Road Interchange, as part of Hamilton's Lincoln Alexander Parkway, required a monitoring program—which included five years of water quality sampling—as a condition of approval by the Department of Fisheries and Oceans. This paper reports on the quantitative and qualitative wetland water quality monitoring data (sediment, nutrients, metals) obtained over the course of a total seven-year program, and provides information regarding the operating conditions and estimates on contaminant removal efficiencies from the facilities.

Stonnwater management systems for new urban development have been traditionally designed and analyzed with the aid of computer models employing design stonn events [such as the Soil Conservation Service (SCS) temporal distribution], rather than continuous modeling using long tenn historical rainfall data and associated frequency analyses. It has generally been accepted that the latter method provides a more rigorous and realistic design; however, the differences in the results (i.e. designs) generated by the two methods have not typically been understood during the planning and design process. Tlus chapter describes a case study in the Town of Milton (Sixteen Mile Creek Watershed) in which, based on a unique oppotiunity, both methods were applied in the analysis and preliminary design of end-of-pipe stonnwater management facilities. The different flow and storage regimes generated by the alternate methods are highlighted, along with a number of modeling and physical factors which are considered to contribute to the differing results.

No abstract

Development (LID) systems on a Watershed basis. The FMS has determined that, due to the intrinsic effects of runoff timing, distributed precipitation patterns and runoff volume increases, conventional practices are not suitable for flood control.

The objective of this chapter is to present an investigation of the robustness of an algorithm for storm direction and speed. The algorithm is used in a utility called "Rainpak,. in PCSWMM. In this chapter we first present an approach for estimating the mean speed and direction ofamulti-cellularrainstorm using rateof-rain gages. The code for spatial analysis of storms and their cells is described. Then we present a Monte Carlo analysis of rain storms observed in Toronto and Hamilton, Ontario, in which we demonstrate the robustness of the analysis with respect to observational uncertainty.