A new Polytunnel - oh my!

Of course, I don’t know your specific needs. I recently saw a high tunnel  where the lower edge of the covering rested in a piece of guttering. The gutter was slightly sloped to feed into a 55 gallon drum on either side of the tunnel. Of course, it does not rain inside a high tunnel, so the drums provided a source of water for the plants inside.

That's sort of my plan for the upper side of the tunnel John - I have gravity on my side there! I can collect the water run off in guttering and lead it into the tunnel into a barrel for storage and overflow (hopefully) into my raised wicking bed and overflow from there into the main growing space. I may add more barrels (if I can get hold of nice ones easily) to add more storage, as I expect still to need to water transplants and seedlings.