  In this paper, we test various models of wastewater infrastructure for risk
analysis and compare their performance. While many representations are
available, existing studies do not consider selection of the appropriate model
for risk analysis. In this paper, we define two characteristics of wastewater
models: the network granularity and the fidelity of the governing equations. We
consider different combinations of these characteristics to determine 6 network
representations that could be used as the foundation for risk analysis. We test
the performance of each model as compared to predictions from the most detailed
model, the full network with dynamic wave flow equations. We demonstrate the
model selection for Seaside, Oregon. We conclude that the full network
granularity is needed as compared to a coarse network representation. For the
fidelity of the governing equations, connectivity analysis is reasonable if the
primary goal is to determine the spatial distribution of hazard impact. To more
accurately predict nodal performance measures, the dynamic wave equations are
needed as they capture important physical phenomena.
