It can be a big deal how physical systems can effect the ecological systems. Living in an area with lakes I have seen how changes to the ecology of the lake has been effected by man made physical systems. The have been some spill ways added to streams that lead in to lake. These streams drain wet lands but in the spring the water is high and bate fish reproduce in those wet lands. The young fish grow and then follow the streams out to the lake in the summer. Those streams are blocked off and the bate fish have no place to reproduce. That is just a small effect of of how Physical systems can effect ecology of an area. I would use this as a lesson to teach students about how the ecosystem work in our area.
A big project that has been proposed over the years by a major land owner in the area is to build a dam on the Milford River that flows out of Lower Gar Lake of the Iowa Great Lakes. The goal would be to flood the land and create more lake shore property. I think I would use this idea and create a unit for students determine the effect on the environment, the flooding of farmland and wild life management area. It going to make a big change to the Ecosystem in the area. The students would take a look at the positive economic benefits of creating more water front property in the area. They could look at what could be the revenue for the county from the taxes. They would lastly have to take a look at the politics that it would take to get this accomplished. The possible pros and con of taking farmland and wildlife area in to a lake.