Using Pathways For Rain Catchment

Here in the drylands of San Diego we need to be especially sure to catch whatever rain may fall. Building good soil is vital for the entire planet because humans are going through decent topsoil like nobody’s business.  Here at Finch Frolic Garden we’ve sheet mulched around trees to replicate decades of leaf drop, and on pathways to block weeds, prevent compaction and create good soil for shallow plant roots.  We’ve also continued making our pathways work more for us by burying wood (hugelkultur) in the paths themselves.  Most of our soil here is heavy clay, so creating drainage for roots is imperative. In sandy soils, creating more fungal activity to hold together the particles to retain water is important. We also need to store rain water when we get it, but not drown the roots of plants. This all can be accomplished by burying wood, the older the better.

Miranda and I have worked on many pathways, but for a few months this year the garden was given a huge boost forward with the help of Noel, a permaculture student and future farmer, who can move mountains in an afternoon with just a shovel.

The chosen pathways had these features: they were perpendicular to water flow, or were between trees that needed supplemental drainage, food and water access, and/or were where rainwater could be redirected.  Eventually we’d like to do all the pathways like this but because of time, labor and materials we worked where it was most needed.

The existing sheet mulch was pulled aside.  Sections of the pathways were dug up (Noel’s work was very neat; my work is usually much less so).  Wood was laid in the hole, and layered back with the dirt.

Notice I said dirt, not soil.  We don’t want to disturb good soil because we’d be killing microbes and destroying fungal networks.  Dirt is another story; it needs amendment.  As we’ve already buried all of our old wood, we timed these pathway ‘hugels’ to coincide with some appropriate tree removal.

Trees were cut down and some climbing roses pruned back out of the pathway, and the green ‘waste’ was used in the nearby pathways.

Old palm fronds went in as well.  No need to create additional work – good planning means stacking functions and saving labor.

After the wood was layered back with the dirt, the area was newly sheet mulched.  Although the pathways are slightly higher, after another good rain (whenever that will happen) they’ll sink down and be level.  They are certainly walkable and drivable as is.  Although the wood is green, it isn’t in direct contact with plant roots so there won’t be a nitrogen exchange as it ages.  When it does age it will become a sponge for rainwater and fantastic food for a huge section of the underground food chain, members of which create good soil which then feeds the surrounding plants.  Tree roots will head towards these pantries under the paths for food.  Rain overflow that normally puddles in these areas will penetrate the soil and soak in, even before the wood ages because of the air pockets around the organic material.

The best part about this, is that once it is done you don’t have to do it again in that place.  Let the soil microbes take it from there.  Every time you have extra wood or cuttings, dig a hole and bury it.  You’ve just repurposed green waste, kept organics out of the landfill, activated your soil, fed your plants, gave an important purpose to the clearing of unwanted green material, and made your labor extremely valuable for years to come.  Oh, and took a little exercise as well.  Gardening and dancing are the two top exercises for keeping away dementia, so dig those hugels and then dance on them!

Burying wood and other organic materials (anything that breaks down into various components) is what nature does, only nature has a different time schedule than humans do.  It takes sometimes hundreds of years for a fallen tree to decompose enough to create soil.  That’s great because so many creatures need that decomposing wood.  However for our purposes, and to help fix the unbelievable damage we’ve done to the earth by scraping away, poisoning and otherwise depleting the topsoil, burying wood hastens soil reparation for use in our timeline.

Another pathway is hard clay and isn’t on the top of my priority list to use for burying wood.  However it does repel water due to compaction and because rainwater is so valuable I want to make this pathway work for me by catching rain.  I’ve recommended to clients to turn their pathways into walkable (or even driveable) rain catchment areas by digging level-bottomed swales.

A swale is a ditch with a level bottom to harvest water rather than channel water.  However many pathways are on slopes or are uneven.  So instead of trying to make the whole pathway a swale in an established garden, just look at the pathway and identify areas where the land has portions of level areas.  Then dig slight swales in those pathways. Don’t dig deeply, you only have to gently shape the pathway into a concave shape with a level bottom.  The swales don’t need to connect.  You can cover the pathway and swales with bark mulch and they will still function for harvesting rain and still be walkable.

If the pathways transect a very steep slope, you don’t want to harvest too much water on them so as not to undermine the integrity of your slope.  This is a swale calculator if you have a large property on a steep slope.

So up-value your pathways by hugelkulturing them, and sheet-mulching on top.  Whatever your soil, adding organics and mulching are the two best things to do to save water and build soil.  And save the planet, so good going!