Andrew Bennett
How resilient is your farm to the boom and bust of water extremes, and how can you improve?
For many, the first thought is better irrigation equipment. The main reason farms call me is for water plans to get funding for upgrades. You know the problems: patchworks of old mismatched nozzles, pipes that leak or don’t release air, high maintenance intakes and filters, low pressure slop and high-pressure mist, clogged drippers, wet spots, dry spots, and so on.
Fixing these problems is important. Water must be applied evenly to the crop’s roots at a known application rate or else you’re guaranteed to waste water.
Others want a total overhaul to increase irrigation efficiency and effectiveness, and to reduce labour. They’re making the move to automated solid set sprinklers, low pressure pivots, booms, microspinklers, or drip. Again, great plans.
Scheduling, however, often gets completely ignored. Proper timing has the potential to improve efficiency more than any equipment fix, but very few farms have a reliable method to match water application to the weather, the soil, and their crops’ changing needs.
But let me back up a step further. Before we consider new equipment or tackle questions like whether your wheelmove cycle ping pongs the crop between flood and drought (it often does), let’s begin with fundamentals: How secure is your access to water in the first place?
Where does your water come from? Do you have more than one source? Are they clean, reliable, and viable, and for how much of the season?
What would happen if your watershed were logged or burned, shredding the “ecosystem sponge” of wetlands and deep soils that normally mete out water through the summer?
What would you do if your aquifer were contaminated, or if snowpacks were low, spring came on fast, creeks slowed early, and drought set in?
Can your farm capture the water that falls on your land from snowfall or a big storm? (That water is yours to use, no license required!) Or does it erode soil, puddle and drown plants, leach nutrients and, worse than useless, flush away?
Who controls your water? Are you licensed for the full amount you require, or do you need to apply for a new license? Do other water users have precedence over you? Did you get that well licensed? Are you part of a water system and subject to their infrastructure, governance, priorities, and restrictions (whether you agree with them or not)?
Further upstream, all water sources are tightly linked to, and depend upon, ecosystems that have vital water requirements. BC’s water managers will tell you that many sources have been over-allocated to irrigation licenses, making future restrictions almost inevitable. Is your license at risk of being curtailed in a drought?
Globally, the toxic combination of corporate greed and political misinformation has left international co-operation on climate change in tatters. What will happen in your region as Earth’s average temperature soars above the fabled 1.5°C goal to 3°C and beyond?
Every fractional increase in global temperature represents an unfathomably large increase in the energy held by our atmosphere and oceans, and manifests (among many effects) as extreme and unpredictable weather. Make no mistake, as our planet hurtles towards an uncertain future, farms are on the front lines.
This may sound like doom and gloom, and it is, but there are good strategies and solutions. As the crux arrives, we’ll all depend on farms and working together in communities more than ever before. We have the know-how, we have the tech, so it’s time to get ready.
For your community to ride this wave, survive, and hopefully thrive, it starts with clear-eyed attention to the facts on your land, a willingness to consider new ideas, and the tenacity to do what it takes—time, money, and sweat—to build your farm’s resilience to the many unwelcome scenarios we might face.
At the very core of resilience, farms must look critically at their water supplies and demands. In my work as a farm advisor, irrigation designer, and water planner, I’ve had the opportunity to visit many farms and help find solutions. Every farm’s needs and circumstances are unique, but I’ll take a stab at some universal truths…
Build Soil
Soil is every farm’s primary water storage. When the tap turns off, you’ll ride out what you’ve stored in your soil. A compacted hard-pan might not store any water at all. A foot deep of thoroughly wetted sand might only have half an inch of water available to plants.
But the same sand—after years of growing the roots of cover crops and filled with worm-chewed mulch, livestock leftovers, and the carbonaceous crud of generations of thriving microorganisms—might have one to one and a half inches of available water in each foot of soil.
Like magic, the same soil life processes can also improve poorly drained soils high in clay or silt, and make both water and nutrients more plant-available.
Deep roots help too. If a foot of soil holds an inch of water, an acre holds 100 cubic meters (26,000 gallons). If you grow plants that send dense roots to four-feet deep, multiply by four!
Shape Your Land
Many of us farm on slopes and should shape the land to catch runoff. Consider terracing or other earthworks designed to slow, sink, and store water, while at the same time improving access and operations. As with all excavation, be very picky to peel off all the topsoil first, and sprinkle it loosely back on top at the end.
If you have space, build water storages. You can get some costs funded, including engineering for dams, a water management plan to map out the big picture, and help apply for the water license amendments you’ll require.
Think big: an acre of farmland might require from 1,000 to 5,000 cubic meters of water in a season, depending on the crop, the microclimate, and the efficiency of the irrigation system. About 2,000 cubic meters is typical, or 10,000 50-gallon rain barrels!
Storage requirements depend on when water is available. If you only have access to the spring freshet, you’ll need to store every drop, plus more to account for evaporation and seepage. But if you have access to a steady low flow all season long, then you only need storage to meet the deficit in peak season.
Farms often don’t want to give up “productive land” for a reservoir or, as I prefer, a constructed wetland. That’s fair, but if your alternative is no water at all, dryland agriculture in much of BC is hardly productive. Where I work in the southeast, well-managed dryland typically produces less than one tonne of hay per acre. A half or quarter tonne is quite normal. Give that land regular water and enough fertility, and you will likely exceed 5 tonnes per acre.
And let’s keep reminding our regulators: When farms grow 10 times more biomass, that’s 10 times more carbon sequestration, some of which is locked in longer term soil storage. Time for carbon credits yet?
Assess Your Irrigation
There are so many ways to waste water. A good bet is to get an assessment by a certified irrigation designer and discuss options with them. You can use your Environmental Farm Plan to get an irrigation or water management plan 100 percent paid for by the government’s Beneficial Management Practice program.
An aside: there are not nearly enough qualified water planners, and very few are independent of a supply company. If you’ve got the chops, consider a career as a professional agrologist (BCIA) and/or irrigation designer (IIABC).
Physical upgrades can be costly, and sticker shock often delays or kills good projects. But better irrigation systems don’t just save water. They should also pay back in higher yields of higher quality crops, all with less labour and maintenance. Centre pivots that replace wheelmoves, for example, usually pay back in about five to 10 years.
If that doesn’t balance the books for you, the business case is clinched if you can get some of your project funded.
Scheduling, by contrast, is totally free and absolutely critical, so make sure you ask your designer for a method to assess your crop, soil, and weather to get the right amount of water to your crop at the right time. There are also plenty of free online resources, including some factsheets and videos I’ve produced.
Monitor Your Irrigation
Finally, you can’t manage what you don’t know. If no weather station near you reliably measures evapotranspiration (see farmwest.com) then install one. Install soil moisture sensors to know if your irrigation schedule needs a tweak. Install a flow sensor to know how much water your system uses when it’s in good shape, and to tell you when it’s clogged or leaking. The sensor can also track how much water your crops actually use through the season. And yes, you can get all that funded too.
This may sound like a lot of work, and it is, but it’s worth it. For too long we’ve treated water as cheap and easy. The time has come to value water for what it is: the essential basis for all life.
Additional Resources:
Five factsheets and four farm case studies (2023)
Four webinars with Bruce Naka (2021)
Kootenay & Boundary Farm Advisors
Andrew Bennett, MSc PAg CID, works with farms across Southeast BC through the Environmental Farm Plan program, the Kootenay & Boundary Farm Advisors, and other programs to improve water and soil management and to regenerate agricultural landscapes. He and Caley Mulholland run a small farm in Rossland with their three young boys. andrew@livinglands.ca
Featured image: The dugout at Amara Farm increases water security in the face of increasing drought. Credit: Amara Farm.
