We see water problems every day on television: too much, too little, too early, too late.
I closely monitor water flow across my property before planting. For fruit trees I create berms to hold soil and catch water as it moves downhill. I have also increased the humus in the soil as well as adding clay for water retention. I have done all this without cash. I berm with rock found on my property, and site berms where there is evidence of water runoff from rain. The berms slow and hold water for longer periods, allowing trees to uptake water and the nutrients dissolved in it. Using runoff from a larger area increases the total inches of rainfall received by my fruit trees.
Another flow of water is when tree leaves pump soil moisture into the atmosphere. This is an important part of the water cycle, but in this arid area, leaves sometimes pump more water out than the tree can take up from the ground. This is why watered plants in moist soil can dry up and wither away. This problem increases with wind and sun exposure. I soften this problem by siting my fruit trees downwind of a pinyon or juniper because they block the harsh winds all year.
I am glad to base my New Mexico food forest on pinyon pine and Juniper. These trees block and diffuse the wind, helping reduce water loss. The also create shade pockets that stay moist longer. I create mini berms for plants in these pockets. They are easy to see if you pay close attention to the plant life.
In the steepest and driest parts, I plant my most drought tolerant native seeds. When I say native seeds, most of the time that means I collected seed myself within a few miles. I use mostly natives. For example, I found a native Golden Currant and will collect seed later this year.
Water catchment from my roof is going to waste and it would be enough to water fruits or vegetables. I repaired the fascia, cut back a tree, and am ready to install the gutter (in my spare time). I have a tank to catch the water.
I have a bare area with erosion developing. Last fall I built a series of mini dams to catch water and soil. The small catchment areas looked like a series of ponds and waterfalls every time it rained last winter but now are filled with soil. I will increase the dam size this year while watching for seedlings.
It is less book knowledge and more observing what happens when it rains. When I am off work, like today, I walk my property before, during, and after rain. How dry was it? How much water fell? Did my diversions focus water where I wanted it? Is my soil retaining water without drowning plants?
What gets past flows down into our valley and creates a pond, where it joins the groundwater or evaporates.