it is 20x20x3ft deep how high can the canopy be off the pond? like enough for me to woalk under it or really low?How big is the pond, Herons are a real problem because once they find a food source they keep coming back and can feed to about 30-36" deep. If the pond is small enough us bamboo poles and garden shade netting to create a raised pavilion over it, They can be attractive and have the added benifit of reducing temperature swings and slowing algae growth.Very few herons will go under canopies like that.