Oh, garden forest sounds awesome to me, that would pay off in hot summers providing more shadows, what I love about adult trees is they don't need much watering, if any at all.
When we moved in to the house few years ago I made some calcs and it's not worth it the investment to collect rain water as during the summers here it generally doesn't rain. But still, I have 2 x 1m3 water containers that I fill at noon and then use the water in the evening giving the well enough time to "regenerate" the water volume ;)
Have a great weekend too, thank you!