What actions can be taken to reverse eutrophication in a lake?

Answer 1

Straw in the lake would not help against already developed algae, because it would be suppressed by them (algae are bigger enemies to straws than straws to algae).
To decrease or reverse eutrophication you have to limit input of nutrients to the lake.
Several steps should be done for this. First, you have to determine which of the sources make the biggest input of nutrients (NPK) to the lake (streams or surrounding lands). Additionally, you can define the limiting nutrient at your lake ecosystem (N, P or K).

Then, if the highest input of nutrients comes from streams or rivers (it is the easiest case), then you might enhance treatment towards the limiting nutrient in water treatment plant (if there is such). In case there is no water treatment plant, you may introduce weeds to the streams, and they would take away nutrients before they enter the lake.

If the major input is made from the surrounding lands (farmlands), some negotiations with farmers should be made to decrease (limit) input of fertilizers to soils. Maybe it is possible to convince them in that ecofarming is more profitable.

Answer 2

I think this may help . Grow barley on the shore ,harvest the barley and put the straw in the lake. It is a natural enemy of algae and will make the water safer to drink and clean up in general.

Answer 3

Cause for funding.