This may not work at all but I might try this since you have no fish in your pond. The water should run in a straight line fromwhere it is exiting the pond. I might buy many of the blue discs that you put in a commode. Put several of them in a mesh bag that is weighted down so that it doesn't move. Start at the dam, drop it as close to the dam as possible. If it doesn't get blue water move it straight back 5 feet and repeat the process. It may or may not work but Mr.Tidy will think you for the business.
