Water for irrigation

Agricultural irrigation is the only use of water that falls under a moratorium on high capacity wells put in place by the P.E.I. government in 2002, and the P.E.I. Potato Board wants the moratorium lifted.

New wells can and have been dug for industrial, municipal and other agricultural use, such as water for livestock. In the last 10 years, 23 freshwater extraction permits have been approved by the province.

Government originally put the moratorium in place to study the issue. The Potato Board argues the province has had ample time to do that, and that the province’s new policy on high-capacity wells, from January 2013, suggests there is an abundance of resources that could be tapped into by potato farmers.

Twelve to 15 irrigation wells were grandfathered under the moratorium, and they currently draw about two per cent of the total water used on P.E.I. Of the major water draws in the province - residential, industrial, livestock and irrigation - irrigation is by far the lightest user.

The Potato Board, in a presentation to the P.E.I. Watershed Alliance, has suggested it would like the province to approve in principle irrigation for another 30,000 acres, with enough water to cover that land in five inches of water over the course of a growing season (12,000 hectares with 12 cm of water). That would amount to adding about 15 million m3 of irrigation water a year.

In a separate presentation to the P.E.I. Watershed Alliance, the Innovative Farm group, an independent group of farmers experimenting with new agricultural practices, said the experience of irrigation at their farms is that on average only half that amount of water would be required.

The chart below illustrates how the Potato Board proposal could impact total water use on the Island.

Irrigation would no longer be the lightest water user on the Island under this proposal. It could also add about 10 per cent to the total water being drawn from the ground every year.

It should be pointed out this is the extreme case. As the Innovative Farm group said, five inches of water a year is not necessarily required. Nor would the province very quickly see 30,000 acres under irrigation. Lifting the moratorium would simply allow individual farmers to apply to drill for an irrigation system. These systems are expensive, costing between $150,000 and $200,000, and are beyond the reach of many farmers.

Farmers with irrigation systems, however, have found that the returns can be significant. The potato board presented information from one farm that was gathered in 2012, a particularly dry summer. It found yields were 50 to 60 per cent higher on irrigated fields when compared to fields on the same farm that were not irrigated.

Other studies have noted a decrease in residual nitrate level of more than 30 per cent in irrigated fields. The presumption is the irrigated plants absorb the applied nitrate fertilizer more efficiently.

Environmental objections

Environmentalists have come out strongly against lifting the moratorium, with groups such as the P.E.I. Wildlife Federation and the P.E.I. Watershed Alliance lining up to have their say at the legislature’s agriculture committee’s hearings on the matter.

These presentations have not only questioned the wisdom of lifting the moratorium. They have suggested the province needs to go back and look at the basics of its water policy.

In particular, the presentations focused on the allowable 35 per cent reduction in the base flow of streams. The P.E.I. Wildlife Federation pointed out this could lead to first order streams being 100 meters shorter. That amounts to significant loss of habitat, the federation said.

Daryl Guignion, a biologist who has worked extensively with environmental groups in the province, was specific.

Guignion pointed out the area around a spring never dries up, and will have old growth vegetation on it dating back 100 years or more. If that spring dries up, the plants will die. Guignion also presented the example of the Bradshaw River, in the Bedeque area. He blamed potato irrigation for two branches of the river running dry in July 2013.

Guignion said a 35 per cent reduction in baseflow in the Morell River could cause the entire east branch to run dry.

The P.E.I. Wildlife Federation also expressed concern about the current impacts of high capacity wells on the Island’s rivers, and not just ones used for irrigation.

In its presentation to the agriculture committee, it said there are three high capacity wells that it knew of in the West River system: one at Bluefield high school and two at a private commercial rainbow trout hatchery. The group said the West River aquifer has not fully recharged since at least 2009.

The federation also questioned the province’s calculation of recharge rate, saying its analysis overstates how much rainfall actually makes it into the groundwater, and that getting that wrong calls into question the foundation of the strategy.

As the 2014 growing season started, the moratorium on wells for irrigation was still in place. Hearings of the legislature’s agriculture committee are continuing through June.