I realised very early on that to make an efficient garden business you needed a pump. No one can water a garden day after day by pulling water from a well by hand. I know because I've tried it. After looking at all manner of pumps we decided to develop and build a prototype horse pump. This, to my mind, is the most appropriate type of pump for these gardens with the following advantages:
Local inexpensive manufacture. Local inexpensive maintenance and repair.
Horses can be fed from the by-products of normal farming (cous or groundnut straw) or forage can be gathered free or grown on the farm itself. ie No fuel costs or transportation of fuel.
Horses can reproduce themselves - generators can't do that! Horses produce manure for the garden.
The horse, if trained properly, can practically "automate" water raising.
Horses can be used for other income generating activities, eg ploughing or transport
The design and manufacture of this pump is proving to be a very long process, considering that I am no engineer myself and many of the people I work with have little formal education or previous experience. We are lucky from time to time to have some more professional help along the way and I have to say we are coming to be quite pump-making experts ourselves - after holding many trials and making numerous mistakes. Pistons, pulleys, counterbalances and bearings hold no mystery for us now. But we desperately need more committed experienced help before this pump will become a realistic working part of the Home Farm Project. We need voluntary help from someone with a knowledge of basic appropriate technology. I will be seeking out such help on my next visit to the UK. When it is operational ours will be the only working horse driven pump of it's kind in the Gambia and could have great potential for affordable water lifting in the rural areas.
Until the development of the horse pump has been finalised, we are successfully using an imported solar pump with a Gambian manufactured hand pump as a backup.