So I want to put in several raised beds in my garden, surrounded by a green ground cover that will stand up to my 3 dogs. Something that is both tougher and uses less water than grass (I live in a mediterranean climate). Any suggestions? I have heard white clover may be a solution, but my understanding is that grows quite tall...
The ideal sustainable ground cover will:
require minimal watering, once established
enrich the soil with nitrogen (for most soils)
build topsoil, aka green manure
tolerate foot traffic
Produce food (in lawns; in your case, only in the foot-traffic area)
Crimson clover is a popular choice, as it's nitrogen-fixing, soft underfoot, and feeds bees -- if you keep bees, they will pollinate your other plants, and you can harvest honey. However, because its flowers are very low, walking on it barefoot carries a real risk of bee stings (been there!).
If your dogs pee in the area, a nitrogen fixer may not be a good choice. Already plenty of nitrogen from the pee, so these plants won't thrive.
If you really like grass, there are a few things you can do to make it more sustainable:
pick a slow-growing variety, so you can mow less often
set your mower blade high. The grass will be healthier, need less water, and compete with weeds better.
water less often, but more deeply. The trick is to get the water to soak in deep, so the grass roots reach down to it.
Trifolium repens (white clover) only grows to about 6" tall and tolerates mowing and foot traffic. It also does well in mixes with grass -- it fixes nitrogen from the air, so helps to feed the grass.
Another option to consider is to let the lawn go wild a bit and see which weeds flourish. Choose those that you like the best, harvest seeds, and scatter them around. You'll end up with the ground cover that is best suited to your particular environment.