This morning we installed a blinking light that floats in the water on 16. The battery is solar powered and the yellow light will start blinking at dusk and will turn off when the sun rises. Many golf course managers have told me that this really does work at keeping the geese and their mess away from the golf course.
We attached the unit to a rope and lowered a cinder block to the bottom of the lake. It will be able to float in a six foot radius and we can remove it this winter.
I had to give this a try plus it's 100% refundable if it doesn't work.