posted 13 years ago
Hi
15 meters head is roughly equal to town water pressure and the larger the pipe the less frictional loss of pressure and more volume capacity so the most efficient and cost effective would be 50mm (2 inch) otherwise the fittings would be cost prohibitive. You would be best using your high dam as your header tank and fill it when needed from your lower dam and reverse sysphon back down the same line, making it very easy to reset your syphon anytime you need to. Ar 3.8m head you will probaly be able to run low pressure sprinklers on short stand pipes.