Two widely used software tools in the management of urban drainage systems are: * asset management systems * numerical hydrodynamic and water quality modeling systems The asset management systems are used in the daily management of inspections, permits, billings, etc. and most often they contain information about the physical systems at very detailed levels, reflecting the complexity and details of the real systems. Numerical modeling systems, on the other hand, require a much less detailed description of the physical system when applied for analysis and planning of extensions and other modification to the drainage system. Keeping the information updated and consistent at these two different levels of detail is no trivial task. Normally, the responsibilities lie within different departments, and there are no formal procedures established to ensure that changes in the layout or dimensions in the sewer system are implemented both in the asset management systems and in the models. Hence there is a great risk that further evaluation of the existing, but recently changed, systems capacity and performance will be incorrect. The proposed paper describes an ArcView application which bridges the gap between asset management systems and the advanced numerical modeling system MOUSE. The application allows the user to extract data from a number of different asset management systems, condense the network automatically - while maintaining consistency in the description of the physical system -and finally store the data as a model for further analysis in MOUSE. All decisions in the simplification process made by the program are based on user specified criteria. All changes are recorded on a separate file, which later can be replayed if an when the user wants to repeat the process, e.g. after changes in the asset management system. Further, the application enables the user to analyze results from the MOUSE simulations within the ArcView program. CSO points and volumes, exceedence of critical levels, etc. can quickly be identified. By virtue of the direct access to the asset management system, the simulation results can also be visualized in combination with parameters describing the actual conditions of the sewer system, e.g. CCTV information.
The purpose of Arcata's recently developed comprehensive stormwater drainage master plan is to identify, quantify and determine the existing stormwater drainage and discharge system including creeks, channels, culverts and pipes and consider various maintenance, repair and design alternatives to maximize the capability of the system at the lowest cost. The plan was designed to provide realistic technical solutions that are economically, socially, environmentally and institutionally acceptable to the community. PC ARC/INFO was used to inventory the infrastructure and develop coverages such as land use, impervious surfaces, soil types etc. Hydrologic modeling was conducted on all city drainage basins in order to identify potential problems and to model a build-out scenario. Workstation ArcInfo was used to model the hydrology identify flood prone areas and create digital elevation models. GIS has allowed Arcata to develop a dynamic database and modelling approach which allows the possibility of considering ever-changing conditions such as the availability of land, new urban planning strategies and goals, opportunities for natural resource enhancement, etc.
The maintenance of water and sewer networks is a serious problem world-wide. Of course, it is always more difficult in developing countries, because of the economic situation. This paper will describe the problems, discuss some of the most important system management implications, and present some solutions employing the latest GIS technology, based upon several years of experience as a water and sewer utilities service contractor around the world.