SIMULATING URBAN HYDROLOGY USING ARTIFICIAL SEWER NETWORKS

Simulating urban hydrology using actual sewer networks can be tedious and even practically impossible for large and/or old areas, especially when considering high spatial resolution requirements of physically-based models. Is there an alternative to using actual sewer networks? What if the general presence of watershed features at a certain scale and configuration is important (e.g. the model needs to have gutters at a certain density connected to catch basins), but their exact location and exact configuration within the watershed is not important. If that is true, then we could generate an artificial network based on some user specified characteristics (e.g. land use, slope, …) and use that as input to the model. The idea is that, although the artificial network may look different, it will produce the same results when applied in a model.

We are currently working on developing algorithms for generating artificial sewer networks for hydrologic simulations in urban hydrology. This paper presents our first model results. A number of artificial sewer networks were generated for the highly-urbanized Faneuil Brook sub-basin in Boston. The artificial networks were created using the Artificial Network Generator (ANGel), which uses the dendritic and space-filling ‘Tokunaga' fractal tree geometry. Actual and artificial networks were used as input to the SWMM model. Comparisons of the various sewer networks are based on the flood hydrograph and various other parameters (e.g peak flow).