Ok i plan to build a stone walkway from my carport down the side of the house to the backyard, up the carport end i plan to have a pond with a waterfall. Im not sure yet on what the exact size the pond will be but i would guess around 40 gallons of water. What im really trying to figure out is how powerful a pump i will need. the pump will of course be in the pond and will probably have to pump up about 3 foot to where the water fall will start. Is there a good rule of thumb to go by when trying to decide how powerful of a pump. I dont have a convient power source near where it will be located so i plan on going with a solar powered pump to keep it simple and they seem to be alot less powerful than others. Thanks for any advice
40 gallons is not a lot of water so you should be able to get away using even the smallest of pumps. Pumps are usually rated by how many gallons they pump per hour (GPH). If you go with an 80 GPH it will move all of the water in you pond twice per hour or once every 30 minutes. A pump serves serval functions, one of which being filtration. If you plan on having plants and fish, then 80 gph should be good. If there are no living things in your pond then you can go lower if you want. Try to selected a pump that has low wattage for the amount of water it moves.
pumps are sized by gallons per hour lifted one foot. You need to use the lift factor also. However for a pond with 30-100 gallons you use a 50 gal/hr pump with a 1/2" diameter hose. (this too is part of the factor)