Integrated keyhole raised beds & irrigation design

I'm sold on the strength of keyhole designs over simple rows, and have determined that the best method for establishing a front-yard garden is to combine blocks of 10x10 keyholes in 50x20 mega-rows. One thing the front yard could really use more of, however, is water, and so I intend to bring as much of it from the back to the front as possible by collecting it via contour swales and carrying it to the front through irrigation ditches. As I've heard time and time again that creating as much edge as possible in undulating patterns is the most effective method for making use of a resource, I've figured that these irrigation ditches carrying the water should be cut right at the base of each raised bed, following the keyhole patterns and bringing the water past a multitude of plants along the way. I'm thinking about alternating each end of each raised bed mega-row with small ponds, and perennial shrubs (to the south) and fruit tree guilds (to the north). I'm thinking about making the paths white clover and lining the irrigation mini-ditches with gravel to cut down on erosion.

So, how do you think this would work? My biggest question is this: if the raised beds are hugelkultur beds and stacked pretty high, will the water rushing past down at the base even have any effect on them? Or would it all be for show and with no genuine benefits?

Also: in retrospect, looking at the design, those ponds are way too large. Being able to draw it out like this has made me realize that the ponds, which I wouldn't want to be much larger than 5x5 for fear of gobbling up all the spring rainfall, would only take up about 1/4th of the raised beds' end caps. More room for fruit trees!

Patrick,

Did you ever build the mega keyhole garden? I am thinking of doing something like that for my new market garden. I would love to know how you built it, including the hugelkultur part. Thanks!

Leela
Kindred Hill Farm
NH