Best mulching/other strategies for capture/retention of seasonally available water

I'm thinking about best strategies for capturing and retaining water in our 5 acre swaled food forest/orchard area. Here in coastal BC, there is ample water supply on an annual basis, but almost all of it falls in winter, and in recent years there's been unprecedented heat waves and months without rainfall in summer. Capturing and retaining the winter rainfall/snow is definitely the key to summer survival of plants.

The soil is sandy and rocky (sandstone) with very little organic water holding capacity.  In the three years we've had the property we've been working to improve the organic matter of the soil with cover crops, chicken tractors, addition of organic material such as manure, plant trimmings and wood chip mulch, and biodiverse understory plantings to shade/protect the soil. We mostly have the wood chip mulch in rings about 1 yard in diameter around our young trees, starting about 6 inches out from the trunk of the tree. More mulch would be nice, but we can't easily source enough to wood-mulch the whole area.

We do water as possible during the worst of the heat waves but it's challenging given the size of the area and the amount of water available. We hope to get to a point where we can hold enough of the winter's water to get through the dry season without providing additional water.

One strategy that might help condense and/or hold water that I feel we haven't utilized to its full potential is adding more large rocks around the trees or in the swale ditches. There are plenty of rocks on our land but relatively few large slabs - mostly broken up sandstone pieces typically around the size of a fist or maybe double that size. I try to throw those out of the alleys between the rows of trees into the swales, to help shade the bottom of the swales and limit evaporation. I don't think these pieces of rock would be particularly effective to promote condensation of water - I think they may be too small. Does the temperature of rocks this size follow air temperature too closely to be effective as moisture condensers? I picture rocks the size of a soccer ball being optimal for this purpose - is that right? I wonder though whether the smaller rocks would work better for this if I can get enough of them to form two or more layers of rocks in the ditch. That could be feasible with a long term rock picking effort, maybe achievable over a few years.

All of these things are helping, but are not enough. We still end up losing trees and understory plants (one could consider this selection pressure and survival of the fittest, I suppose). We've definitely selected the most drought tolerant of our trees during these three years of crazy heat and drought. The ones that are thriving are really green through the summers although I feel their above-ground growth is slower than expected - hopefully, we are in the phase where most of their energy is going into getting their roots down through the sandstone to water. We plan to plant more that we've started from seed to fill in some of the gaps; I'd like to give these the best chance of survival so I'm trying to think how to get the biggest bang for our buck in terms of interventions. What I mean by that is: we have limited time and funds to improve water capture and retention. What is the most effective approach?

I don't think these are mutually exclusive approaches, and we will likely continue to work on all of them, but I'm curious to hear what others think are best practices in this situation:
- increase organic matter of soil
- increase living cover of soil
- extend the coverage/thickness of wood chip mulch on the planting berms
- incorporate other mulches on the planting berms
- add more mulches in the swale ditches, and if so, which kind
- add more rocks, or larger rocks, for water capture through condensation - if so, should these be on the berms or in the ditches

What else?

Have you dug any test slices into the ground to see what the deeper underground layers might look like? Im thinking 2-3 meters deep, or more, if this is possible.  This should help you figure out what earthworks might make the most sense for your unique situation.  

Capturing and retaining the winter rainfall/snow is definitely the key to summer survival of plants.

There is a really cool image I just came across on social media that shows the difference between a mowed area and a non mowed area, and how this can affect water retention in the landscape in the wintertime.  Attaching below.  

It is a great example of a simple change that we can make which actually creates less work for us.  Sometimes its not about what we are doing, but what we aren’t doing.  A nice example of “Do Nothing Farming,” as coined by Matsanabu Fukuoka?

Have you shaped any infiltration basins around the property?  A crater garden could be pretty awesome.

https://permies.com/t/37563/Crater-Gardens#293578

The soil is sandy and rocky (sandstone) with very little organic water holding capacity.  In the three years we've had the property we've been working to improve the organic matter of the soil with cover crops, chicken tractors, addition of organic material such as manure, plant trimmings and wood chip mulch, and biodiverse understory plantings to shade/protect the soil. We mostly have the wood chip mulch in rings about 1 yard in diameter around our young trees, starting about 6 inches out from the trunk of the tree. More mulch would be nice, but we can't easily source enough to wood-mulch the whole area.

There is a great article that was shared in the Water Stories community by Zach Weiss recently that relates to this.  

https://www.resilience.org/stories/2023-07-17/millan-millan-and-the-mystery-of-the-missing-mediterranean-storms/

From the article: “The more life in a landscape, the more water it can “milk” from ocean flows. It’s a self-amplifying circle: water, through life, begetting more water, begetting yet more life, gathering yet more water, and around it goes, the result being increased climate cooling and moderation.”  

As mentioned in the linked article above - what we often don’t think about is the water found in living organisms. The more life there is, the more water.  It’s like having a bunch of living sponges everywhere.  Anything that goes through its own lifecycle will eventually return its stored water/nutrient, and something else will gladly take it up.

Swales (depending on context), mulching, diverse understory and cover crops, shade, and animal manures can be of a great benefit. You seem to be doing a lot of things right Andrea!

Biochar could be of additional benefit as it is a more stable carbon source, but as you may already know it can be difficult to create enough of it efficiently for a larger scale system.  In small batches over a longer period of time you could strategically, and incrementally, add it to the areas which might benefit the most.  It needs to first be charged/activated in a high nutrient and microbial environment, such as liquid fertilizer or compost pile.

If you haven’t seen it already Pearl Suttton just created her own small batch process that could be fun to replicate, or be inspired by to innovate:  

https://permies.com/t/235724/biochar-burn-Itty-bitty-Pearl#2161053

Have you looked into keyline design?  How about terracing?  Both of these are considered much more cost effective than swales and are typically much easier to work around and manage -  especially if there is machinery and farm equipment involved. Best bang for the buck. Also there is less chance of creating unintended harm to the landscape.  

One strategy that might help condense and/or hold water that I feel we haven't utilized to its full potential is adding more large rocks around the trees or in the swale ditches

I don’t think that the size of the rocks matters that much. If anything i would think that the fist sized rocks you have an abundance of are great because there will be more surface area.  This would help create more habitat for more life, which as stated above, can help you store more water.  It is possible that the soccer ball size rocks are more ideal for condensate capture, but this is something I don’t know enough about and am also beginning to look more deeply into. Thanks for bringing it up! Im also hoping to see what others respond with on this topic.  

More mulch would be nice, but we can't easily source enough to wood-mulch the whole area.

In my own practice this is something I am beginning to transition away from as much as possible.  Bringing in mulch can be very time consuming and strenuous, and there is the question of what mysterious toxicities might have snuck their way in at any stage of the process before getting to you.  It might, however, be necessary depending on the context.  If you have the land and space available to strategically grow cover crops that can be easily scythed or mowed, and placed into rows or along edges right next to where they are being cut - this might be more ideal. In Syntropic Agroforestry it is taught that 2/3 of the land can be used to fed 1/3.   Grass is a favorite mulch material because it grows fast and can be very easy to cut and harvest as needed. Plus it feeds livestock.  Cows can live on a 90% grass diet. Easy to prune or coppice tree species along other boundaries or edges might be something to consider too.  

Are you hugelkulturing at all?  

I don't think these are mutually exclusive approaches, and we will likely continue to work on all of them, but I'm curious to hear what others think are best practices in this situation:
- increase organic matter of soil

- increase living cover of soil

- extend the coverage/thickness of wood chip mulch on the planting berms

- incorporate other mulches on the planting berms

- add more mulches in the swale ditches, and if so, which kind

- add more rocks, or larger rocks, for water capture through condensation - if so, should these be on the berms or in the ditches

What else?

Living Cover - Increasing living cover of the soil comes down to seed and species selections in my opinion.  A great way to do this could be by “landracing” everything. Here is an excellent free course that covers the topic, which was recently made available by Joseph Lofthouse

https://permies.com/t/173814/Adaptation-Agriculture-online-Joseph-Lofthouse#1364479

Organic Matter - Increasing organic matter in the soil comes naturally with living roots, microbes, fungal hyphae, and sun energy being injected into the  earth via the “Liquid Carbon Pathway”.  This could also help offer insights into how to help your trees grow better.  Here is a short presentation by Dr. Christie Jones on the Liquid Carbon Pathway:



Mulching - As stated previously, it is of my opinion that focusing on mulching with wood chips or other materials can create much more work than it’s worth. We can design a system where the need is minimized, or greatly simplified, with all mulch materials coming from your own land.  Ultimately the best “mulch” is a living green cover.  

Condensation - I, too, want to learn more!  If I come across anything really good Ill try to come back and share.  

The above reply was really terrific, but I really have to say that personally I find wood mulch to be awesome. The first year or so it's not the most exciting but it really starts to pack down around year 2 or 3 and especially if you have snowy / wet winters it gets smushed into the ground and breaks away. I tend to use a lot of organic nitrogen fertilizer partially for the plants and partially to help break down the wood chips.

A couple of more exotic solutions are to create guzzlers (rain catchment) that go into an olla. I've been experimenting with some of those for my trees. If I had to do it all over I'd scrap the olla and just use a vertical mulch tube of sorts, or even a perforated pvc pipe. I built a simple 1'x3' frame with corrugated roofing on it, with a very slight angle, and routed that runoff into the olla.

Andrea Locke wrote:The soil is sandy and rocky (sandstone) with very little organic water holding capacity.

I'm in a similar ecosystem, although I've got more clay in my soil. The trick there is to get the water to actually soak in, rather than running off hydrophobic dry clay!

I've noticed one thing when having to dig holes (other than all the rocks - I grow big rocks and they are an issue in their own way!) If I came across decomposing tree roots, I usually would also find living fine tree roots infiltrating the dead wood. Is this Nature's version of hugelkulture? Are those roots harvesting nutrition or moisture? To imitate it, I've taken wood that was a bit too punky to be fire wood, but typical firewood size and buried it up-slope of trees, 6 inches to a foot below grade. Dry wood floats, so rather than risk instability, I use relatively small pieces and don't go overboard.

and wrote:

In the three years we've had the property we've been working to improve the organic matter of the soil with cover crops, chicken tractors, addition of organic material such as manure, plant trimmings and wood chip mulch, and biodiverse understory plantings to shade/protect the soil.

Have you tried compost holes? My soil is so hard to dig in, my holes end up being wider in diameter and less deep than references I've read, but the ideal is sort of like a post hole - 1 ft wide by 3 feet deep - which you dig and then fill with compostable material. It helps the water infiltrate deeply, encourages the worms, and gets organic matter down where tree roots can seek it out. I tend to do this beyond the drip line if possible to encourage the tree roots to spread and reach and secure the tree from wind storms. I can also add a bucket of water in the summer and know that it is seeping in rather than evaporating from the surface.

I also try to incorporate biochar as Arthur mentioned, and since my rocks are bigger, I'm trying to use rock piles near some of my recent plantings.

Being at the south end of the Salish Sea I am experiencing the same weather pattern.  My observations and adaptations has been to leave tall grass standing to shade the field soil and mow it just before the fall rains placing it in the swales to keep the evaporation down and start the decomposition process.  In the clay field I rake the grass out of the ponds in the swales when they remain full so that they become frog propagating and then refill them with spring mowing before they dry.
The way the land was formed by glaciers and flooding the higher sun facing portion of the farm is more sand and larger rocks at the top.  I prefer to use small rocks for pathways and larger ones as mulch on the sun side of banks. Rocks have an interesting character as a mulch. they block the evaporation under them, absorb heat more rapidly than other mulches and then radiate it to the sky at night but also to nearby vegetation.  So a stone on the sun side of a plant that prefers warmth at night is an effective permaculture plan.

I like wood chips, but interestly, I tried  prepping a bed without putting down cardboard first, which I had done previously...thank goodness.  The non-cardboard bed was riddled with weeds.  I was rather shocked, because the wood chips were two feet deep or more in places! (My neighbor had a gigantic elm cut down and didn't want the chips!)

The most moisture-retentive solution I've found has been leaves...and they are SO much lighter and easier to move around!  I have an electric leaf blower, that when run in reverse, mulches the leaves right into a large garbage can.  Originally, I was using them in my vegetable garden and out back to feed the mushroom patch, but when I saw how well they suppressed weeds and helped hold moisture, I was hooked.  I want to really do all of my pathways now, too.  Once mulched, I don't have to worry about anaerobic soil, them blowing around or weeds growing through. I have a leaf-sweeper that I pull behind my electric ride on mower.  I wish it held more leaves, as I end up doing hundreds of trips, but even so, it is much easier than wood chips.  The leaves do eventually break break down so that they need to be reapplied, but they do seem to last the year.  I also find that because they are darker in color than wood chips, they look more attractive in a bed.

Your garden is still quite young, but the sounds of it.  As the crowns of trees fill in, as do the shrub layer, etc. that will go a long way toward moisture retention, too.  My front gardens are only three years old, and I had to water them for hours every other day in their first year or two.  This past year, I think I watered once.  Although we had an extremely rainy summer, it began with drought.  We hadn't had rain for a few months, yet things had grown enough-- the roots were deeper and the crowns were fuller, so that they really were fending for themselves very well.  It sounds like you're at that turning point.  I don't know how much land you're trying to keep irrigated, but along with wood chips or leaves, there are always plant solutions.  Mint will surely cover ground as will strawberries or even purslane!

Lots of really good ideas here and appreciate them myself.
I'm soaking up all the resources I can from Geoff Lawton on Permaculture
until the online classes start since going to Australia isn't an option right now.
I've been here going on my 4th year. The first two years had been great along
with amending soil in ways that was needed and had terrific growing seasons.
There has been a lot of chemical spraying in the air and last year everything
died due to the aluminum and other things being sprayed.
So rather than stay downtrodden I'm focusing on finding solutions.
I will be using leaves as mulch and covering as much as I can with shade cloth or something I hope
will be effective once I can get the soil restored somewhat.
Also will be draining the small ponds and letting them refill again as well as covering them as well.
I don't have all the answers yet but am planning to do some biochar and
wood vinegar and do everything I can to get some healthy soil
Also growing a lot indoors.
I realize if your property is large you have to find ways to do water retention.
One way I will be trying is using two clay pots sealed together and the hole on the bottom sealed
filled with water then buried in the ground to release water
as needed in areas near the fruit trees to see if can stimulate growth and plant some carbon
producing plants near them too. I'm hopeful for some restoration.
Whoever had this property before me for some reason has tons of small rocks all over the place.
So far I've been using them in the ponds but maybe a way of retaining moisture using them will be
valuable too.
Everyone sure has me thinking now a lot more on solutions.

My advice is a gravity/ siphon well. That all depends on groundwater levels to be able to pull/siphon the water up to a barrel or tote and you'll have water year round. I use this type of water for my animals and greenhouse. They require no power once established.

Not so much a large area strategy but perhaps catching rainwater in large tanks, IBC totes or the like?

This would give you enough water to keep a garden and some fruit trees going through drought, or, do much more than that with a big tank and a bit of processing gear.

https://www.edwardsaquifer.net/rainharvesting.html

https://greatescapefarms.com/really-large-rainwater-harvesting-system-a-how-to-post/

a good read for how to have a garden pull through in unusually dry conditions would be Steve Solomon's Gardening When it Counts.  That also goes into hand watering ideas to conserve moisture and save a garden. He started out in the Pacific Northwest, so all his writing addresses the things unique to there, then he moved to Australia, where water is rare, so learned a lot about that circumstance.

One way to improve the soil is  humates.  These usually last from 4-7 years from one application (can apply 100 - 400 lbs/acre).  They hold water, stimulate biology, break down chemicals, hold nutrients so the growing plants have access to these nutrients, break up clay soils, and many other good things.  Global Humic Products out of Sherwood Park, Alberta, CA sells humates - website is  https://www.global-humic.com - They should be able to find a local store in your area to work with. They also have good information on humates at their website.  Do you have earthworms in the soil now?  Do you have a section of your acreage that earthworms can be introduced?  Earthworms will definitely get the soil broke up, pull organic matter down into the soil for the soil microbes to use, and supply calcium, nitrogen, etc. from their castings for the growing plants.  Focus on the organic matter and fungi for the soil as this will change the soil for the better - higher organic matter, improved soil biology functions, etc.  Hope this helps.  Blessings

Andrea, IMO you've already got it figured out... increase organic matter of soil
- increase living cover of soil
- extend the coverage/thickness of wood chip mulch on the planting berms
Keep doing what you're doing

Worm poop...Can't go wrong by adding worm poop

Hi.

I deal with simillar conditions in the interior of BC. Perhaps you can improve the microclimate around your trees. For example, plant some comfrey, yarrow or any hardy nitrogen fixers along with some companion berry bushes. This will reduce water needs & improve soil allowing your trees more time to get established.

Steve

Dave Bross wrote:Not so much a large area strategy but perhaps catching rainwater in large tanks, IBC totes or the like?

This would give you enough water to keep a garden and some fruit trees going through drought, or, do much more than that with a big tank and a bit of processing gear.

I love all the creative methods everyone has mentioned. Nice!

But in any situation where there is significant seasonal rainfall, I think it's imperative to grab it with both hands -- and store as much as you can. IBC totes, or hand-dug ponds with poly liners, or machine dug ponds with huge impermeable (poly?) liners. Or whatever you can arrange, even if imperfect, as long as it's not toxic.

We live in interesting times. Rainwater is liquid gold. My 2c.

Andrea, I am amazed how warm you have it there, and I am 4a but do have the sandy soil and 8-12' snow (microclimate in mountains)
I have been making increasing use of wild spinach  /  lambs quarters. I don't know if it will grow for you, or if it will grow so well it may be a pest!

I use it not just as green manure, and to eat of course, for myself, pets and livestock, but this past year, with no watering during the drought, I thinned it out a bit but mainly cut down the weeds to 3', allowing it to shade my veg crops somewhat, and again about a month later, and just left it in place until fall, effectively crowding out weeds between my veg. I had almost as successful crop as in a normal year: as if I had watered on occasion in a non drought year, and probably because the frost came so late, I still had plenty of produce.

There was a section I simply left fallow, with mostly stinging nettles and lambs quarters, and in fall, i composted the lambs quarters against a nearby new compost hill on contour, but with the roots tuxked in the hill, planted in the rain. The nettles I will transplant next spring nearby but where I am most likely to have risk of a thief trespassing. If nettles will grow I recommend you try them. They are perennial really hardy, and come up early so they should suck up a lot of spring melt.

The other thing you could try is thimbleberries.Again, super hardy, love sandy soil, come up early and drink a lot of water when they can get it, taste great, good pollinator. Rubus Odoratus.

I wish you the best of luck with your new experiments! Let us know how things go!

I don't know if you are familiar with using mushrooms as a soil remediator.  The research is astounding.  If you can get Paul Stamet's book, Mycelium Running https://www.amazon.com/Mycelium-Running-Mushrooms-Help-World/dp/1580085792/ref=asc_df_1580085792/?tag=hyprod-20&linkCode=df0&hvadid=312132076760&hvpos=&hvnetw=g&hvrand=4064424666468987306&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1027411&hvtargid=pla-435508122845&psc=1&mcid=60a0352525c232ecbfeba0ed6a49bd7d&gclid=CjwKCAiAzc2tBhA6EiwArv-i6eeXwpFoDPZ6OON4Tpews741gJrAuFIroNjIqlOtJTSacDLG961jLBoCaF8QAvD_BwE  I would highly recommend it, but basically, using mushroom spawn to clean the land of toxic chemicals can be done relatively easily and inexpensively.  See if your library has the book or can get it through Interlibrary loan.



Lots of really good ideas here and appreciate them myself.
I'm soaking up all the resources I can from Geoff Lawton on Permaculture
until the online classes start since going to Australia isn't an option right now.
I've been here going on my 4th year. The first two years had been great along
with amending soil in ways that was needed and had terrific growing seasons.

There has been a lot of chemical spraying in the air and last year everything
died due to the aluminum and other things being sprayed.
So rather than stay downtrodden I'm focusing on finding solutions.

I will be using leaves as mulch and covering as much as I can with shade cloth or something I hope
will be effective once I can get the soil restored somewhat.
Also will be draining the small ponds and letting them refill again as well as covering them as well.
I don't have all the answers yet but am planning to do some biochar and
wood vinegar and do everything I can to get some healthy soil
filled with water then buried in the ground to release water
as needed in areas near the fruit trees to see if can stimulate growth and plant some carbon
producing plants near them too. I'm hopeful for some restoration.
Whoever had this property before me for some reason has tons of small rocks all over the place.
So far I've been using them in the ponds but maybe a way of retaining moisture using them will be
valuable too.
Everyone sure has me thinking now a lot more on solutions.

Someone above mentioned keyline design, which can be tied to one concept of using a single shank ripper behind a teactor to essentially create a very narrow trench. Mine is about 18". The book "Water for any Farm" by Mark Shepard goes into detail about the positive water holding and soil building outcomes from doing this. P.A. Yeomans was the original compiler of this technique.

I'm more central/east USA and it works good around here but I unserstand your terrain, or access to that equipment might not not allow you to try it.

I have noticed the surface "sheeting" down of water during heavy rains on my 15-20° slopes has decreased. The idea is that it goes a foot or two below where it's held much longer preventing initial erosion and recharging the water saturation capacity of a landscape.

I am in a similar situation in NW California. Woodchips here have recently been harder to come by as people, including larger ag and landscaping businesses learned their value. In addition to many of the excellent suggestions above (apologies if this is a repeat of one I missed), as I thin my overgrown 60yr old forest of ladder fuels for wildfire mitigation, I use this woody debris for watershed restoration projects and mulch around fruit trees. The watershed restoration is along the lines of Bill Zeedyk’s methods, and slows the drainage of the water table as I try to reverse the incisement of stream gullies and generally make the water travel further and have more residence time for the soil and aquifer to absorb it. Where I use it for mulch, I break it down just enough to have soil contact every foot or so and this encourages saturation and fire retardant fungal inoculation of the wood. Coarse woody debris is key to forest health, and chipping wood, thereby increasing the surface area of higher C:N wood, is what creates soil N deficits as it initially decomposes. Larger pieces are also less prone to spread fire.