Doing a little more research over these pump. I found this
site, Go to the Link - Ramp Pump Design Specifications (Institute for Appropriate Technology). What I like about it, is the site layouts how to find out your rate of water flow and other info all in Metric. It also breaks down the make up of the system and the layouts that work.
Mr. Harsey,
From doing more reading, yes these pump do have a water waste at the beginning or startup of the pump. This is two fold: First because the main chamber (pressure) is filled with air, and this acts as the pressure mechanism to push the water out of the pump. This chamber must fill up with water. This chamber acts as an "air bladder" to prevent water-logging or air-logging. The homemade Ram Pump site list a Bike Tube, I've also seen a Ball. Also there is a poppet or release valve at the beginning of the Pump on the down hill side (Inlet).
Anyone used these before?