A simplified version of these artificial beaver dams will work great in a desert gully or runoff channel where a “plug and spread” dam is impractical because there is nowhere to spill the water.
Substitute t-posts and use old net wire on the downslope side. Fill with logs, branches and grass. A series of these are “speed bumps” that protect the spreader dams from flood crest top-overs. Like the recoil reducer in a shotgun, these man-made dams briefly absorb the flow and energy of water and then release it relatively slowly. Intensity—speed and peak volume—are reduced as the flow period is lengthened and dispersion width is increased. There is no effort to permanently capture or impound water which is spread and temporarily backed up therefore soaking the dam’s uphill side. As it slowly spreads across a wider area, it then more effectively soaks the downhill side.
These artificial dams reverse erosion because the slowed runoff deposits its sediment which raises gully or channel bottoms. Build other dams above and below as needed. Where opportunities exist, employ these in combination with plug and spread dams to evacuate the water from the gully onto adjoining flats.
We can’t make it rain more but practices like these make the rain we get more effective—and that’s just like getting more rain.