Drought-tolerant grass for sunny, wet Texas clay

Question

I live in Texas, and my back yard is on the bottom of a hill; thus it gets lots of run-off from other houses in the subdivision. The run-off causes problems you'd normally expect:

• Soft, boggy lawn especially in the shallow drainage swales that were put around the house to deflect downhill run-off
• Tough to keep grass looking good because foot traffic easily flattens it (due to high moisture content in the clay). We have a young child, and it would be nice to have BBQs / backyard kiddie-pool parties that didn't cause lawn damage.

I have considered planting St Augustine, which has a good reputation in hot, boggy soil, but there is another problem. St Augustine requires a lot of water, and our area of Texas has had problems with drought.

Is there any other grass that will accomplish all of the following?

1. Tolerate drought without a lot of water
2. Stabilize persistently-damp clay soil

Our house faces south, so the lawn is on the north side of the property (if that matters). We do have a mature Spanish Oak on one side of the lawn (the tree gives some shade to a corner).

Answer 1

Of course, the best solutions to a drainage problem is to divert water, re-grade the slope, and/or improve the soil. That said, these solutions are not always possible.

My suggestion for suitable plants would be to try Carex praegracilis:

A short, rich-green sedge selected by John Greenlee as an alternative to turf grass. Growing to 6-8 inches tall and spreading by rhizomes to form a carpet that tolerates moderate foot traffic. A good plant as a solid ground cover, between and around stepping stones or mixed with other bulbs, perennials and grasses to create a natural meadow look. It tolerates full sun to partial shade but has a period of summer dormancy in warmer, drier climates. Moderate water requirements make this plant not quite drought tolerant but certainly lower than most lawn grasses. It is hardy to at least 10 F and likely to come back from the underground rhizomes after lower temperatures. from San Marcos Growers

Another possibility is Carex divulsa [C. tumulicola, Hort.]:

It is a very versatile plant for use in coastal full sun to fairly deep shade. It tolerates boggy wet soils but is also fairly drought tolerant once established. from San Marcos Growers