Can anybody point me to a resource that would be useful to design a ground water tank? I have never designed one of these before (well maybe in college) so I'm starting from scratch.
How much pitting can be tolerated in a ground water storage tank before it needs to be replaced? How are repairs made? Just weld an internal patch over it? How extensive does the pitting have to be before the tank needs replacing?
Concrete - PCA pub on 'circular concrete tanks without prestressing' is a good reference & has stood the test of time. PCA also has a pub on rect conc tanks. PCA have a below ground tank design, I think.
Steel tanks - I just follow AWWA D100 (VERY conservative) or API 650.
10 States usually call for 24hours of storage. This gives you time to drive somewhere, but a well pump or part, drive back and get it back in operation before your customers run out of water!