I have a customer who has a pond in the back yard. The pond collects runoff from the neighborhood. The customer would like to extend his grass about 6 feet into the pond. At 6 feet out, the depth of the water is approx. 2 ft. deep. Please refer to the picture (attached) for an idea of the situation (the green line indicates the desired outer edge). Do you think I can simply add dirt/fill to elevate the shoreline? Or do I need to use a pond liner, retaining wall, etc. to ensure the shoreline holds? Thanks in advance for your suggestions!