The challenging issue of irrigation on Prince Edward Island

Wednesday, July 16th, 2014

The economy of Prince Edward Island, in Canada’s east coast maritime provinces, is dependent to a large degree on its primary sector. Fishing, aquaculture, and agriculture produce the majority of the province’s gross domestic product. The largest agricultural sector is potato growing.


The potatoes grown are both table supply and supply for processing into end products such as potato chips and French fries. Irrigation is already used in the potato industries, and is considered ‘supplemental’, as the island receives a regular supply of rainfall. Although it is variable across the Island, average precipitation is 1100 millimetres per year. Irrigation is not used every season, and when it is, it is only at certain critical times of the potato growing cycle. Sometimes this is necessary to ensure that the potatoes grown are of a suitable size, shape, and quality for the processing companies. In many years, only 50 millimetres of irrigation is applied in a season.


Irrigation water is sourced primarily from groundwater, although there is also some surface water abstraction.


Prince Edward Island is entirely reliant on groundwater for its drinking water. The deepest drinking water wells are at a depth of around 800 metres, but the most productive wells are less than 200 metres in depth. Most private bores for drinking water extend to a depth of around 60 metres. Although the Island abstracts a fairly high volume of groundwater for irrigation, drinking water, aquaculture, and food processing, its aquifer levels are maintained through extremely high recharge rates. Thirty four per cent of precipitation goes directly to groundwater recharge.


In 2002, in order to limit the amount of groundwater which can be abstracted, the Provincial government paced a moratorium on new groundwater abstraction for irrigation purposes.


In order to ensure that there is adequate water supply for irrigation during the critical growth phases, there have been requests to allow for further abstraction of groundwater from deep groundwater sources, using ‘high capacity’ wells which draw water at a rate of up to 50 litres per second. These requests have been led by a producing and processing company, Cavendish Farms who have requested that the government lift the moratorium.


The Ministry for the Environment’s abstraction policy which calculated the amount of water that can be withdrawn was previously related to the amount of recharge. In 2013, in response to some community concerns around the effects of increased abstraction should the moratorium be lifted, a new policy was developed which linked the amount of water available for abstraction to the effects of abstraction on connected surface water stream flows. However, this new policy has not alleviated the community concerns, and many on both sides of the debate are unconvinced as to the accuracy of the scientific modelling of the aquifers which has been undertaken.


It should be noted that irrigation for agricultural purposes only accounts for one percent of the Island’s groundwater abstraction, with the same amount of water being abstracted for the watering of golf courses, thirty percent used for industry and food processing, and sixty percent used for residential purposes. No moratorium applies to abstraction for any of these other water uses, and are still granted.


A complicating factor is that nitrate levels in the Island’s groundwater is increasing. A government appointed commission to examine the issues of nitrates made a series of recommendations to the government in 2009 as to how nitrate rates should be reduced. There have been some improvements in farming practices in recent years, due to programmes such as the Alternative Land Use Services programme, which provides financial incentives to farmers to undertake actions above and beyond basic compliance, in consideration for the provision ecological goods and services. This programme is cost-shared between the Federal and Provincial governments.


The government has also supported the development of Community Watershed Planning Groups, to undertake stream enhancement projects across eighty per cent of the Island’s 255 watersheds.


Despite these good processes, water quality issues remain concerning, with anoxic events occurring frequently in the Island’s estuaries, and fish kills occurring due to pesticide contamination.


In order to address all of these thorny issues, the Provincial government has announced that it intends to legislate in the form of a new Water Act. Ostensibly, the policy direction and content of the Act has not yet been determined, rather it is intended that the Act will reflect the will of the community. A third party is to be engaged to lead an extensive process of community consultation, the outcomes of which will inform the content of the legislation. As well as setting new rules around abstraction, the Act could include regulations around nutrient management to control nitrates entering ground and surface water.


The government is attempting to bridge the gap between public opinion on the one hand, and the need to support economic development through support for the Island’s largest employer.


Winston Churchill Fellowship to Canada – water management, farming practices, and research programmes

Saturday, July 12th, 2014

As Policy Manager for the Waitaki Irrigators Collective, I have been fortunate to have been made a 2014 Churchill Fellow and was awarded a travel grant from the Winston Churchill Memorial Trust.


I am using my travel grant to journey to Canada, to spend some time in most of the country’s provinces, learning about the Canadian approach to water management, various assessments of beneficial farming practices, and integrated research programmes. The Canadian Water Network (CWN) links different groups together in various watersheds to develop programmes and assessments of all issues related to water management. The CWN are hosting my trip, and have been very generous with their time and support in helping me develop my itinerary and linking me up with people on the ground.


My journey started in New Brunswick, where I spent time touring the nuclear power facility at Point Lepreau with the New Brunswick Energy Institute, followed by time with New Brunswick government representatives who showed me the new dam and reservoir at Turtle Creek which provides municipal water supply to the town of Moncton. I then visited a New Brunswick dairy farm, where I learnt about the dyke system which prevents the inundation of farmland from the high tidal bores experienced in the Bay of Fundy. I explained the dyke system in more detail in my first post.


Following New Brunswick, I moved on to Prince Edward Island (PEI) where issues around water quality and the use of groundwater for supplemental irrigation are creating considerable debate amongst the local community. My next report will be on irrigation in the potato industry on PEI. My trip to the island was made more exciting by the arrival of the post-Hurricane Arthur storm which hit the Atlantic seaboard of the USA and Canada! Power went out on much of the Island for several hours and a large number of trees and property were damaged.


I then went on to Ottawa, where I will be met with various groups, including the Canadian Federation of Agriculture, Agriculture and Ari-Food Canada, the Canadian Federation of Dairy Farmers, and the Ottawa Riverkeeper. I also be met with an academic and writer, and the New Zealand High Commissioner and our First Trade Secretary for Trade and Economy. I was able to spend time with a representative from the South Nation watershed Conservation Authority, when I learnt about their nutrient trading programme, which is made successful through their incentive funding for the implementation of farm management practices to reduce nutrient runoff.


Following on from there, I have been to Toronto and regional Ontario, and I will then be going on to Manitoba, Alberta, and finally British Columbia. I will try and provide regular updates on this site about what I have learned, including case study reports like the one on the dyke system.


Thanks to all those who have supported me so far on my trip, and I hope you enjoy reading about my travels and experiences.


Elizabeth Soal

The New Brunswick dyke system: 300 years of water management

Saturday, July 5th, 2014


During the Acadian settlement of New Brunswick during the 1700s, in the Atlantic Maritimes area of Canada, the settlers recognised the productive potential of the clay soils adjacent to the Petitcodiac River. This land provided a much more stable soil base from which to farm, compared to the more mobile soils in the rolling downloads further from the River.

However, the Petitcodiac River is not like any we know of in New Zealand. It drains into the Bay of Fundy which, due to its unique funnel shape, creates the highest tides in the world. The tides near Moncton are known as tidal bores. The incoming tide creates a wave down the river, historically up to nearly two metres high. The tide’s sheer size and speed would create an audible roar, and would travel upstream at an average velocity of 13 kilometres per hour. This tide would inundate the fertile land on the riparian margins. Conversely, the retreating tide leaves the entire fairway in a condition more akin to an estuary than a river. The tidal events became a significant tourist attraction and curiosity.

In order to prevent the daily inundation, the settlers built a system of hydraulically controlled dykes, which would prevent the tidal flood, but would still allow water to drain off the farmland in times of heavy rain. The system proved highly effective, and the dykes continued to work as flood control mechanism for over 200 years. The ultra-high tides that occurred annually would over-top the dykes and so some natural inundation remained. The stable soils mean that there is little in the way of run-off, despite its close proximity to the River.

However, in the 1960s, it was determined at a political level that there must be a better, more permanent

solution could be developed. Where the River passes through the city of Moncton, a large causeway and dam structure was built to allow traffic to cross the River, and stop the tide before it reached the farmland upstream. Initially, this seemed to be an effect solution. However, the Petitcodiac River is naturally very high in silt, and much of this was carried up the River by the tide as suspended sediment.

The introduction of the causeway meant that this silt could no longer be distributed over a wide area of river bed, and instead it started to build up on the downstream side of the causeway at a rate of 1cm per high tide or 2cm per day.

This gradual build-up of sediment meant that the River could no longer perform in any way close to its natural function. The Moncton bore was reduced to a normal tidal event, with little wave and no sound. It was felt widely that something important had been lost.

In 2010, the dam was permanently opened, and the dykes again became crucial structures for flood control. The sediment loads in the River bed are reducing, and the tidal bore is now able to be surfed! The causeway remains, but it will likely be replaced in the future by an alternative transport route, likely a bridge.

Geological movement means this part of New Brunswick is sinking, whilst climate change increases sea levels. The dyke system may become even more important for protecting New Brunswick’s productive farmland than ever before.

An interesting aspect of the system is that maintenance of the dykes rests with the provincial government, rather than the landholder on whose land the dyke exists and protects. The Province recognises the importance of the dyke system to its economic wellbeing, and maintains a management partnership with its farming community.