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The irrigation ditches her father dug have given way to automatic drip systems but Lorraine Bennest knows that even the most sophisticated system is useless if there’s no water to run through it.

Bennest, who has 15 acres of apple trees in Summerland, British Columbia, Canada, was on the front lines of the issue in 2003, when Canada’s Department of Fisheries and Oceans shut down access to Trout Creek—the main source of water for the town—to protect fish habitat. While growers were still able to harvest a decent crop that year, it was a sign that things had to change if local water supplies were to continue to serve the needs of all users, including fruit growers.

"When we have a drought year, when there isn’t enough water available to us, that same year is likely to be a really high demand year," she said. "Now the question is, will we still have enough water? I can put it on really ­efficiently, but will it still be there for me?"

The closure of Trout Creek was one of the reasons Bennest ran for Summerland council in 2005, and is active with the Okanagan Basin Water Board, a regional body established by the province in 1969 to oversee the region’s water resources. It is coordinating a federal-provincial study of water supply and demand in the Okanagan Valley in order to better understand the situation and help the region plan for the future. A final report should be ready in 2009.

Writing checks

The study is the first comprehensive survey of local water resources since 1974. It will estimate present and future water demands and potential supplies, accounting for a variety of factors including population growth, ­climate change, and land use.

"The first principle is to really find out how much water there is in the basin, because we don’t feel like you can manage it before you know what you’ve got and what you’re working on," said Anna Warwick Sears, executive director of the water board. "We’ve kind of been writing checks without knowing how much is in the account."

A crisis isn’t imminent, Sears says, but she notes that changes are needed to manage the growth expected in the valley. The population of the Okanagan is projected to top 395,000 by 2020, up from approximately 343,000 today, and a recent study of food security for the province’s Ministry of Agriculture and Lands suggests that significant new acreage will be needed to meet the province’s domestic food requirements.

Water will be critical to the growth of both the local population and agriculture, meaning greater existing supplies and future demand will require greater attention. Sears thinks it is foolish to think the Okanagan is beyond the kind of crises that have hit other parts of the world (such as the wildfires that swept through California last year or the drop in levels of the Great Lakes).

A change in climate could have an especially significant impact, as it promises not just higher temperatures but new patterns of precipitation delivering less snow, more rain and less runoff into the lakes that are the ­traditional holding areas for the basin’s water.

"The predictions here are that we’ll have longer, hotter, drier summers, which means that crop water demand will increase," Sears said. "Then, at the same time, we’re going to have warmer winters with less snowpack, so we’ll have less water available during the height of the irrigation season to supply that increased demand… It’s that pinch point in the late summer that we’re most ­concerned about preparing for."

And the pinch could be severe.

Hotter weather

Projections by Dr. Denise Neilsen, a research scientist at the Pacfic Agri-Food Research Centre in Summerland, suggest that some parts of the Okanagan Valley could post extreme temperatures up to 12°C (22°F) higher within 50 years.

Those increases would accelerate evapotranspiration in orchards and vineyards, boosting water requirements unless steps are taken to better manage demand—­something the province is encouraging.

"When you start targeting the Okanagan and how we’re going to manage water, you really start to look at what we’re doing with our irrigation for agriculture and landscaping," explained Ted van der Gulik, an engineer with the resource management branch of the B.C. ­Ministry of Agriculture and Lands.

Van der Gulik notes that irrigation of agricultural, residential, and commercial properties account for about 85 percent of current water demand. Just 15 percent is for other types of home use. Answers about how much water exists in the Okanagan watershed and what the actual demand is won’t be known until the water study is complete next year, but van der Gulik said it’s clear that the onus of ­management is on those who irrigate.

"We’re probably not going to want to give up any water for agriculture, because we know we’re going to need more water down the road. I don’t think we’re going to be able to get any more water, so the challenge is to be able to make do with what we have," he said. "We’re going to have to manage way better than we do now."

Water metering, which has been in place since 1994 in the South East Kelowna Irrigation District and is being tested in five other districts, is one tool to manage water use, but improving on-farm irrigation systems is also important.

More efficient

A federal-provincial planning initiative administered by the B.C. Fruit Growers’ Association has supported approximately $2 million worth of irrigation upgrades, with grants to orchardists and vineyard owners totalling more than $500,000. The improvements make irrigation systems at least 15 percent more efficient.

This spring, van der Gulik expects the province to release a host of new on-line tools that pair water study data with real-time climate information to help farmers better gauge irrigation requirements.

The tools include an on-line application that will allow growers to compare their water use with the benchmark for their area, which should tell them if they’re doing a good job or not in managing water. A pilot version will run in Summerland and Vernon prior to its launch in other areas.

A dedicated Web site, www.irrigationbc .com, will help growers establish an irrigation schedule that suits local conditions. Growers will be able to enter soil type, crop type, irrigation system type, area under cultivation, and other variables to determine how frequently and for how long they need to irrigate. "You have to give people the key to see if they’re doing a good job or not," van der Gulik said.

That’s fine by Bennest, who is keen on the growing wealth of information available and the advances being made in technology that help deliver water more efficiently. "It’s a great time to be farming I tell you—it’s really interesting. Really interesting," she said. "It’s not that these [water issues] aren’t real challenges. But I think we’re really well positioned."