Structures & Equipment
Water and irrigation
Water efficiency Inside View: January 2015
By Gary Jones
Tapping into high costs of water and drought
By Gary Jones
Wouldn’t you know it? I’m asked to write this month on “water management” and there are rainfall warnings in effect in the Fraser Valley. North Vancouver is cleaning up after a night of heavy rain with six creeks overflowing, causing localized, but severe, flooding and property damage.
At the other extreme, California produces nearly 50 per cent (by value) of the U.S. vegetables and non-citrus fruit and we’ve all heard of their drought and its claimed links to rising food prices.
But drought is only partly to blame: “price increases are lagged due to the time it takes for weather conditions and planting decisions to alter crop production, which then influence retail prices…. However, other factors such as energy prices and consumer demand also affect retail produce prices. For example, prices for fresh produce fell in 2009 despite drought conditions, as the 2007-09 recession reduced foreign and domestic demand for many retail foods.”1
WATER EFFICIENCY IS CRITICAL
Aside from numerous other reasons, partial contribution to higher food prices is a fair reason to be conscious of water use. Efficiency is critical. Greenhouse growers have known for a long time that their production systems are water-efficient. At least compared to field crops.
Can we do even better?
“The MIT CityFARM team has already grown produce such as lettuce and tomatoes, using hydroponic, aquaponic and aeroponic production systems. Coupled with new diagnostic, sensing, automated and autonomous delivery and harvest systems, the team says their process has the potential to cut water use for agriculture by 98 per cent.”2 They also claim a faster crop growing time – roughly three to four times faster.
In the U.K., urban agriculture startup Zero Carbon Food “has found that growing produce in abandoned London Underground (subway) tunnels, away from light and fresh air, has a host of benefits, including 70 per cent less water usage than open-field farming.”2 A good move, since agriculture accounts for 70 per cent of the world’s fresh water use.
THE COST OF WATER
One of the options for encouraging more efficient water use is through pricing. How much does water cost? In (wet) Vancouver, there are two rates as determined by the season: “During the rainy season, when the city’s water supply is at its peak (November through May), residents and commercial businesses will enjoy a low off-peak rate. During the drier months, when demand on the water system is high, rates [will] increase by about 25 per cent, to reflect the added cost of supplying water to the city.3
“This summer surcharge will help [Vancouver] meet its Greenest City 2020 goal of reducing water consumption by 33 per cent, which has two benefits for all Vancouver residents:
Reduce the strain on existing water system, eliminating the need for costly system upgrades that could lead to higher utility rates,
Help [citizens] live within [their] water means, ensuring that all residents have access to abundant safe, clean water, no matter how much the city grows.
“Metered water and sewer rates are measured in units. [In Vancouver] one unit equals: 2,831.6 litres (= 2.83168466 cubic metres or 100 cubic feet). For 2014, the costs in Vancouver are
Oct. 1 to May 31 CDN, $2.385 / unit, and June 1 – Sept. 30, $2.988.”3
IMPACT OF DROUGHT CONDITIONS
In drier areas, e.g. California, recent prices reflect increasing levels of drought.
“Farmers in California‘s Central Valley, the world’s most productive agricultural region, are paying as much as 10 times more for water than they did before the state’s record drought cut supply. Costs have soared to US $1,100 per acre-foot from about $140 a year ago in the Fresno-based Westlands Water District, which represents 700 farms, said Gayle Holman, a spokeswoman. North of Sacramento, the Western Canal Water District is selling it for double the usual price: $500 per acre-foot, about 326,000 gallons (1.2 million litres).4”
But, do the math (and if I’m correct): something is a little odd. Water costs about half as much in drought-ridden Sacramento than it does in rain-soaked Vancouver. I’ll leave you to ponder that and we’ll catch up later…gotta’ dash; it just stopped raining.
- Source: www.ers.usda.gov, accessed October 2014.
- www.HortiDaily.com, accessed October 2014.
- www.Vancouver.ca, accessed November 2014.
- Alison Vekshin in Bloomberg, accessed July 23, 2014.
Gary Jones is co-chair of Horticulture at Kwantlen Polytechnic University, Langley, B.C. He serves on several industry committees and welcomes comments at Gary.Jones@kpu.ca.