I have this idea of pipe irrigation. Following is an explanation of the various elements.
- The bottom layer represents the limestone bedrock or caliche base common to areas around Central Texas. It can be used as a foundation for the overall setup.
- The blue in the front represents typical water flow pattern. See this document for a more detailed analysis of how water flow actually is expected to occur.
- Just above the water flow graphic, there is a trough. The top of the trough is at ground level. The bottom is just deep enough to contain a porous clay pipe. After the pipe is laid into the trough (which must be horizontal), the trough is filled with pea gravel and then topped off with stone or brickwork. This setup allows for easy maintenance.
- The round disks represent flat stones or brickwork laid above the soil. The soil occurs in the 18 inches from these stones down to the bedrock.
Plants are planted between the flat stones. The stones, appropriately chosen to not be hot stones, serve to shade the soil and to physically block evaporation directly from the soil. They also block weeds. If preferred, a mulch layer could be used instead.
The pipe is closed at each end. And elbow or T-joint somewhere goes up to the surface providing a place for water to be introduced to the system. Alternatively, the clay pipes could extend into a pond whose surface is at or above the top of the pipe shown. In that case, the pond would simply need to be maintained at an appropriate level to facilitate irrigation.
Fish raised in the pond would also provide a very low dose of fertilizer to the plants.