Here's a great resource page: irrigationtutorials.com They have lots of information covering just about anything and everything you might want to know about irrigation systems. Great resource, especially the section on drip emitters.
wildrose: The water rationing requirements forced on state residents by the idiots in Sacramento during the drought were not very carefully thought out. Many trees died as a result and many trees wound up falling on buildings and causing a lot of damage because their root system deteriorated. When water is rationed provisions should be made for trees and home owners should get a subsistance allowance per tree. Something like 100 cu ft per tree per month would be about right.
cactuspete: Trees are an important environmental resource. If we are actually in the midst of global warming or climate change, then allowing trees to die only makes matters worse. If not, then a drought is just a temporary issue and its best not to allow trees to die over something that will be over within a couple years. Either way better to defray the damage than to accelerate the downward spiral.
No doubt that trees are a big investment and that allowing them to die would be short-sighted to say the least. Any rationing system should most definitely take into account the pre-existing trees and shrubs already planted at a residence and provide adequate water credits to keep those plants alive. Bureaucrats seldom realize the long term effects of their actions and so I wouldn't count on this happening, but if intelligent people are running things then this would be something you would be able to count on.
tronagirl: It almost seems like whoever made this is something close to resourceful, but the usefulness of this little project is obviously very limited. On top of that it looks really tacky! LOL