The diagram below show the problem of flooding in a UK town and two possible solution

The given map illustrates the picture of two solutions for the problem of flooding in England town.
Overall, the town experienced a process of changes to prevent water. The first solution was beneficial to the environment but the cost was high. For the second measure, it had low cost but the land could be affected.
In solution one, all three buildings were built out of the flooding zone. The industrial area and residential area were moved to the north of the flooding area. The commercial building located in the south of the flooding area was constructed out of that.
In solution two, a dam was built in the north of river A to separate a reservoir and the river. For the west of the river, there was a dam which was constructed to prevent water from the west reservoir.