I've discussed in past posts that there is a lot of vacant land near Denver that could be used for urban farms, but most of it does not have water access and getting water installed is prohibitively expensive. With only 15 inches of rain a year, there is a very limited range of vegetable crops that can be grown without irrigation.
What if a farm was laid out in alternate rows on contour 8 feet wide, and every other row was a plastic covered low tunnel. However, the plants would not be growing in the low tunnels, but in the open rows. On the long sides of the tunnels the plastic would be buried in the bottom of shallow mulched trenches.
This would give the uncovered plots the equivalent of 30 inches of rainfall. Furthermore, light rains that would have merely evaporated off open ground would be concentrated into the trenches and sink into the soil, thus boosting efficiency of water usage.
Would this set-up work to grow standard vegetable crops? (Combined, of course, with mulching, varietal choice, etc.)