One of the best things about my house in Carbondale, CO is that it's adjecent to the town ditch. It's a simple and logical system which could easily be applied to any new commuminty design if there is a river nearby.
The Carbondale Ditch is water re-directed from the Crystal River during the spring and summer months. Originally designed to irrigate the ranching community in the valley, the town ditch now runs in a network throughout the various neigborhoods and town parks of Carbondale. Anyone who owns property adjacent to the ditch in this relatively dry valley may connect a pump and use free irrigation water.
Envisioning a new community where people will be usings thier lawns for food production, and public areas will support several community gardens, the design of a ditch network similar to Carbondale's would allow for irrigation without a complex system of pipes and municipality-controlled water usuage, and wouldn't require everyone's home to be along a river.
The ditch system also provides a network of pedestrian and bike paths which go right through people's back yards, allowing a more open and integrated social network than your typical suburb.