The grass in the photo looks like a dwarf Pennisetum, like 'Little Bunny,' 'Little Honey' or 'Piglet.' All are very small Fountain grasses and would do well in your application as long as you give them a bit more water than their neighbors require. You could also look at several of the Carex varieties and Festuca.

You could consider Sporobolus heterolepis, or Prairie Drop seed, which is a short prairie grass with fine foliage and delicate flower panicles. It has good color in the fall and the little birds like to eat the seeds. The seed heads have an interesting spicy scent. It is very drought tolerant and once established would not require any extra irrigation.