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<br />, <br /> <br />Because of advances in computer technology, it is relatively straightforward <br />to develop such schemes. For example, Chapra and Byars (1995) have developed <br />a fully dynamic transport and fate model to predict the movement of a water <br />wave and associated pollutant transport for Boulder Creek. Such models <br />effectively simulate both the magnitude and timing of hydrographs and pollut- <br />ographs during extreme flow events. It is relatively trivial to extend such <br />schemes to simulate the transport and fate of several interacting pollutants <br />(Runkel 1993). <br />A continuous simulation capability is essential in order to characterize <br />the expected intensity, duration, and frequency of water quality changes in <br />receiving waters. Using a continuous receiving water simulation model, what <br />is the expected variability in stream water quality especially downstream of <br />the Boulder Wastewater Treatment Plant? Given this information, what is a <br />reasonable way to formulate water quality standards that incorporate both dry <br />and wet weather inputs? <br /> <br />5.5. Blending Water Supply Deliveriss to Minimize Water Quality Changes in <br />the Distribution System <br /> <br />The City uses water from three different sources, each of which has a <br />distinctly different water quality. This mixing causes relatively wide <br />swings in water quality in the central part of the system with attendant <br />problems with corrosion. How can these sources be better mixed to reduce <br />this variability in water quality? Working in cooperation with the City of <br />Boulder, selective sampling of water quality changes in water distribution <br />systems will done. EPANET will be used along with the watershed simulation <br />to estimate the expected water quality changes under variable demand patterns <br />(Rossman 1994). The expected impact of water conservation in reducing peak <br />water demands will also be assessed. <br /> <br />5.6. Dynamic S~ula~ion of ~he Perfo~ance of ~he Wastewater ~reatmeDt System <br />during Periods of High Inflow. <br /> <br />An unprecedented construction grants program in the 1970s provided the <br />financial resources for urban areas to vastly improve their wastewater treat- <br />ment systems. As part of the construction grants program, individual appli- <br />cants were required to demonstrate that their design was cost-effective in <br />several. ways including using regionalization where appropriate, and managing <br />infiltration and inflow. As these wastewater systems approach their design <br />capacities we are seeing increased problems with sanitary sewer. overflows due <br />to inadequate capacity during peak flow events which are usually associated <br />with high water tables and storm events. The output from the continuous <br />simulation model will be used to predict seasonally high water table levels. <br />This information will be used to provide improved estimates of sewer infil- <br />tration rates. The feasibility of high-rate operation of the wastewater <br />treatment system during these peak periods will be explored using GPS-X <br />(Barnett and Tukacs 1993). <br /> <br />6.0 Workshop on Future Directions of Urban Watershed Management <br /> <br />Using the results of the first phase of this study which will demon- <br />strate the benefits of integrated evaluation of urban watershed systems, a <br />workshop will be convened to explore future directions of model andDSS re- <br />s~arch. An Engineering Foundation format is planned. Invited participants <br />w~ll be asked to present state of the art papers on their particular special- <br /> <br />13 <br />