Economic
If the lake reduces in size there will be less fish so there will be less fishing which means that there will be less food for the area. Business's will be lost so the town or city wont have as much money as they used too therefore they wont be able to buy in food that was lost because of the reduction of the lake.
Social
The loss of water means that there will be less water for families to drink also meaning that there is no fish and meaning less food for people to survive on. Since there is a lack of jobs and food people might move away in search of better jobs so they can bring in food for their families. Some children born around here are born with birth defects because when the mother is pregnant she is breathing in the salt and harmful pesticides from the drying up of water.
Environmental If the lake dries up the area around the lake wont be as hydrated as it used to be so trees wont grow as well so birds and other animals that live in trees wont stay there. Also reduction of water size the fish that once lived there move to nearby streams to be able to survive in more water.
find out more here
https://www.youtube.com/watch?v=Z0Pi61SyVSM