Building an irrigation system in the Ark

There are a number of things in the pipeline here, and after just receiving torrential rain in Catalonia I wished I could have got this done earlier. Basically the head pressure to operate the drip irrigation comes from a small water tower which needs to be raised by another two levels. It works at the moment with a battery-operated water timer which opens and closes a valve once a day feeding water into 7 irrigation lines; each can be turned on and off according to what is growing at the time. The small pond I am building in front of the central bed will be waterproofed and house beneficial wildlife all the year round. It stays continually topped up because the next stage in construction is to waterproof the paths also between the beds, thus collecting quite a lot of run-off after it rains. This is then directed into the pond, and a bilge pump with a float switch will control the level by starting up, triggered by a 12-volt battery