The first day we were in Mendoza we drove an hour or so into the mountains to go white water rafting on the Mendoza River. Apparently the water was especially high that day so conditions were better than a typical day. We didn't lose anyone, but we came awfully close to flipping the whole raft at one point, I was only saved by my right foot being slipped into a pocket attached to the floor of the boat. It was awesome, that was the best part.
Despite being quite lush, we were told that due to lack of rainfall Mendoza is technically a desert. They are able to grow all the grapes for wine production by skillful irrigation using the Mendoza River, which is fueled by plenty of snow melt coming off the Andes. There is an intricate series of irrigation ditches and gates to divert the waters to specific properties and they each have designated time periods and allowances to coordinate the water usage. A large benefit is that the vineyards can carefully control the water flowing to the vines to specifically tailor the amount to the plant's needs. Eliminating this one variable of nature's whim is a great boon to the winemakers, as a late season rainstorm before harvest can wreak havoc with the quality of the grapes in other wine growing regions of the world. There is, as always, a trade off however, because what little precipitation Mendoza does get often comes in freak hailstorms which can wreak havoc of their own. One winery we visited, Achaval-Ferrer, had recently lost the entire crop at its main vineyard two years in a row! (They make really excellent wines, if you are curious.)
We also visited one of my favorite bodegas, Catena Zapata. Here is the view of their main finca, or vineyard, from the top of their (faux Aztec pyramid) winery: