What inference can you make about the effect of tides on health in jamestown?

Jamestown was situated on a site that was too secluded for agriculture, in fact, the entire island was isolated because it was swamp-like and infested with mosquitoes and the only water came from tidal rivers. This water was unsafe to drink, which could cause health problems such as cholera, typhoid or dysentery.  I give credit to @Barnuts
But i agree with this but hope this helps.

Reserved powers is your answer

Earthquake fault lines. map above represent