Important points in desert water harvesting strategies:
--Reduce evaporation! The definition of a dryland is that there is more evaporation than precipitation.
--Slow, spread and sink the flow. Water usually comes to the desert in downpours that don't have a chance to soak in.
This particular location is undeveloped in terms of it's planting, which could be altered to make more productive use of the abundant soil moisture.
Similarly I imagine that a trickle irrigation system could be installed if the trapped sand and silt were used as a reservoir to extraction.
Bret Glassett wrote:Are check dams really beneficial to natural systems or are they actually disruptive? As I watch the video I'm thinking that check dams are all great - but I also recently watched the documentary DamNation and it points out the many issues with using dams and how they disturb natural watersheds. What's the difference? Are check dams okay only on seasonal drainages? Or?
I would argue that logic is human biased. By that I mean there where a lot more beaver dams around until the mountain men hunted them to near extinction. Who knows what a natural watershed actually looks like?
The effects of these events are usually short lived as the water has rapidly flowed away down stream and out to sea. With a check dam a portion of that surface water (and a pretty small portion at that!) is held back in the silt and soil behind the dam wall where it spreads laterally to the surrounding soil and down stream. Where these systems are used plants can thrive on the increased soil moisture and whole ecosystems can be revived.
In my own work, I have built hundreds of check dams and rather than relying on the structural stability of the stone, intend to use taprooted and shallow-rooted plants to stabilize the structures as they retain more and more water. I think with plants stabilizing the hydrology and slowing down erosion, and by using large boulders instead of small stones, we can avoid the pitfalls of check dams and create structures that will last a very very long time.
Check dams are not for the untrained to use though; they're tremendously easy to do poorly, but poorly done they almost never function well. Furthermore, I don't think they should be used at all in eroded gullies, but in more stony and mountainous regions where erosion is less likely to undercut them.