However I can't be absolutely sure that those effect you mentioned can always be ignored but it is very hard to know right input values for them even though I wanted to take them account.
This is closely related to one of the interesting things in life. If one looks at many finite element calculations, microscopic particle simulations, etc one has to notice that most of the effects cancel each other and where they do not, simple phenomena arise together with phenomenological laws. Laws that do not depend much on details of the underlying interactions.
I am leader of the
www.urbanflood.eu consortium that creates an early warning system for dike failures. In the Netherlands we have about 2400km of realy crucial dikes and some 16000km dikes that are a bit less important. However as the composition of dikes are only partly known, if any, as the measurement of this composition is neither technical possible and feasible, we realy can not rely on fundamental theory to understand sensor readings. Instead, I stimulate the uptake of data driven modelling techniques. As dikes are "exited" by passing ships, tides, cars, rains we model their response.
The more scientific side of me is drilling down on "emergence" and the control of complex systems. Appart from dikes, "swarms" of spacecraft, telecommunication networks, wafer steppers are application cases.