Discuss the problem, being sure to include:
Some background. Describe the geography of the area.
Some history. When did this occur? Is it ongoing?
Some background. Be sure to define any terms that are particular to your problem (like eutrophication)
Some chemistry. What chemicals are involved? Include molecular formulas, reactions, and equations if applicable.
Some effects. What problem(s) did this cause?
Some solutions. What has happened to address this problem?
Anything else particular to your problem.