A small shopping mall, behind which is a stream, was flooded during a heavy rainfall. The owner of the stores in the mall sue the owner of a large arena that was built recently upstream of the mall. The arena has a large parking lot. The store owners indicate that they had never experienced flooding in the last 20 years prior to the construction of the arena. The owner of the arena believes that the recent storm is unusually large and his arena is not a factor for the flooding. If you are hired as a hydrologist to help resolve this legal matter, how would you approach? Explain.