A hydraulic ram or impulse pump is a device which uses the energy of fallingwater to lift a lesser amount of water to a higher elevation than the source.See Figure 1. There are only two moving parts, thus there is littleto wear out. Hydraulic rams are relatively economical to purchaseand install. One can be built with detailed plans and if properlyinstalled, they will give many trouble-free years of service with no pumpingcosts. For these reasons, the hydraulic ram is an attractive solutionwhere a large gravity flow exists. A ram should be considered whenthere is a source that can provide at least seven times more water thanthe ram is to pump and the water is, or can be made, free of trash andsand. There must be a site for the ram at least 0.5m below the watersource and water must be needed at a level higher than the source.