Interesting discussion all. Wanted to weigh in here as I research water management in Yunnan. From my perspective there are many factors contributing to what is technically a "drought". Population growth, industrial needs, agricultural needs (tobacco, the most profitable industry in the province is highly water consumptive - note water use and consumption are different), and mismanagement (over irrigating crops, under the table allocation) are all contributing elements.
In my opinion there is one key contributing factor that has not been discussed which has been crucial to the water shortages we now have (due to a decline in rainfall) in the center of the province. *note, HFCAMPO is right, look at rainfall patterns spatially rather than numbers for the whole province, there has been a decline in the dry areas in recent years*
That is deforestation.
Some great reporting done by ChinaDialogue on the issue here: www.chinadialogue.net/[...]
Deforestation contributes in two ways:
One, by removing original forest and re-planting with monocrop trees (or nothing at all) rainfall no longer slowly moves through the soil. A balanced ecosystem will hold rainfall like a water tower in the soil and gradually release that water into rivers. As soil drys, water passes through rapidly, causing flash floods and making irrigation access difficult.
Two, fewer trees means less evapotranspirated water into the atmosphere, which means rainfall patterns change. I hypothesize that that element has greatly altered the amount of rain the "drought" ridden parts of the province now receive. Rainfall will vary year to year, but I would not be surprised if the next 20 years we see less rainfall in these drought areas than in the past 20.
Anyway, deforestation is just part of a large management problem. It would be nice to see demand-side water conservation incentives rather than simple rationing (as we all fill buckets before the water turns off anyway, neutralizing the rationing effort) and many of the points you all brought up above. Just thought I would raise your attention to yet another environmental issue.