This lake is also our drinking water source (after much treatment), so I think that rules out chemical, and I really think mechanical is going to be out of the question.
This may be too late for consideration - but fluridone may still be a viable option. Potable water treated at rates less than 150 ppb (which is an excessively high dose for coontail) may be used without delay, providing that no treatments are literally applied (directly placed) within 1/4-mile of a "functioning" potable water intake. And, if applied at lower dosages (between 6 and 20 ppb), areas immediately adjacent to functioning potable water intakes may be treated. Overall, a single 60-70 ppb dose would probably be quite effective - or, a long-term sustained concentration of 25 ppb.
Have you already pursued a course of action?
Edit: The above applies to the US label. You would need to verify and adhere to local regs for Iraq - if any.
