Agricultural Water Use Survey

Detailed information for 2007

The Agricultural Water Use Survey is conducted to gather information on water use, irrigation methods and practices, and sources and quality of water used for agricultural purposes on Canadian farms.

Data release - June 6, 2008

• Questionnaire(s) and reporting guide(s)
• Description
• Data sources and methodology
• Data accuracy

Description

The Agricultural Water Use Survey is conducted to gather information on water use, irrigation methods and practices, and sources and quality of water used for agricultural purposes on Canadian farms.

This survey is part of the Canadian Environmental Sustainability Indicators (CESI) initiative and is also the result of a collaboration between Statistics Canada, Health Canada, and Environment Canada. The data collected will be used in CESI's reporting activities. The information will also be used by Agriculture and Agri-Food Canada to inform water use policy and development of programs for Canadian irrigators. Statistics Canada will also use the survey results to improve the modelling of irrigation volumes by type of crops and as part of the water accounts.

Reference period: Calendar year

Collection period: February to March following the reference period

Subjects

• Agriculture and food (formerly Agriculture)
• Environment
• Environmental quality
• Land use and environmental practices

Data sources and methodology

Target population

The target population for this survey is the Canadian farm operations that do irrigation. The surveyed population includes agricultural operations with sales of at least $10,000 that reported irrigation or owning irrigation equipment on the 2006 Census of Agriculture. Operations excluded: farms in the territories (Yukon, Northwest Territories, Nunavut), institutional farms (e.g. government, university and prison farms), Indian reserve farms, community pastures, pure hatcheries and farms producing only Christmas trees.

Instrument design

The Agricultural Water Use Survey (AWUS) questionnaire was designed to collect new data on agricultural water use, water sources and water quality.

The AWUS questionnaire was designed by a project team made up of Statistics Canada's Agriculture Division and Environment Accounts and Statistics Division, Agriculture and Agri-Food Canada, Environment Canada employees and provincial experts. Questionnaire design specialists from Statistics Canada's Questionnaire Design Resource Centre (QDRC) were consulted. There were two phases of testing. In January, 2007 moderated focus groups were conducted in Lethbridge, Alberta (22 respondents), Kelowna, British Columbia (16), and Brantford, Ontario (21). The questionnaire was updated based on feedback from the first round of testing. In March 2007, one-on-one in-depth interviews were used to test the updated draft versions of the questionnaire with 26 farm producers interviewed in four regions: Ste Catharine, Ontario; Joliette, Quebec; the Annapolis Valley, Nova Scotia; the Abbotsford area (Central Fraser Valley), British Columbia, and in the Moose Jaw-Swift Current area in southwest Saskatchewan. Participants represented various types of agricultural operations. The questionnaires were then revised based on questionnaire design specialist recommendations and a second round of consultation with Agriculture and Agri-Food Canada employees and provincial focal points or experts.

Sampling

This is a sample survey with a cross-sectional design.

The survey frame came from the 2006 Census of Agriculture (CEAG) and included all farm operations that reported irrigation area or ownership of irrigation equipment and that correspond to the criteria mentioned in the target population section. The sampling unit was the farm operation.

Stratification was done by province. Since the survey was conducted for the first time, the derived variable Total Irrigation Water Use (WU) was used to stratify the population into homogeneous groups. WU was obtained by using CEAG 2006 data with an irrigation model that considers the province and the area of crops irrigated and adjusted by the ratio of the total irrigated area to the total reported area by general type of crops. Four strata were targeted by province (0 WU, very large WU, some WU (x2)), with the exception of Prince-Edward Island and Newfoundland and Labrador where only three strata were used since the number of units in these provinces is small (0 WU, very large WU, some WU (x1)).

The sample size was set at 2,000 units across Canada. Sample was first allocated among provinces using proportional square-root allocation based on the number of farm operations in each province. This method keeps the existing relations between provinces while reducing the impact of larger provinces. It was found that the initial sample size in Newfoundland & Labrador and in Prince Edward Island was so close to the population size that the whole population for these provinces was taken. Provincial sample was then distributed to all WU strata using multidimensional distribution method. A sample coordination process with other surveys was also used to take into account the cumulative burden on common units for different surveys. In other words, within a stratum, the units with a smaller cumulative burden had more chance of being selected. Once the sample was selected, the inactive units were replaced by active ones to reach the objective of sending 2,000 units to data collection. Inactive units were kept in the sample to reflect the frame, i.e. they represent other inactive units that we do not know about.

Data sources

Data collection for this reference period: 2008-02-04 to 2008-03-02

Responding to this survey is voluntary.

Data are collected directly from survey respondents.

Interviews for the AWUS were conducted from Statistics Canada's regional offices in Winnipeg, Sherbrooke and Halifax. A Computer Assisted Telephone Interview (CATI) data collection application was developed for this survey. Prior to collection, a letter explaining the goal and objectives of the survey, along with a description of the information asked in the questionnaire, was sent to the respondents. No paper questionnaires were sent. Since it is a voluntary survey, no follow-up was done.

The target response rate was 75%. The national collection response rate was 81.4%, which yields an effective sample of 1,628 completed surveys.

View the Questionnaire(s) and reporting guide(s) .

Error detection

Edits were built into the AWUS CATI application. When an edit failed, the interviewer was prompted to correct the information, with the help of the respondent. Once data collection was completed, edits were made at the micro-data level to correct capture errors. A set of variables were derived from the data to compare records and identify the outliers for water use. Finally, at the macro level, the survey results were compared with the total water volumes estimated through modelling.

Imputation

This methodology does not apply.

Estimation

After edits were performed, the initial weights were adjusted to reflect the sample response. Two sets of weights were used to produce estimates for the survey population: one set for the water volumes and another set for all the other variables. This was done because a questionnaire was considered to be completed even if data on water volumes were missing, in order to lower the response burden. Estimates were produced at the provincial level. The quality of these estimates was assessed using their coefficient of variation (CV). CVs were calculated with the Jackknife method, using the software used by the Agriculture Division for their surveys.

Quality evaluation

A comparison of AWUS's resulting water volumes was made with previous estimates obtained through modelling. Data were also compared with administrative data sources where available. However, the possibilities to confront data with other published sources were limited, given the fact that the AWUS is the first study of its kind in Canada.

Disclosure control

Statistics Canada is prohibited by law from releasing any data which would divulge information obtained under the Statistics Act that relates to any identifiable person, business or organization without the prior knowledge or the consent in writing of that person, business or organization. Various confidentiality rules are applied to all data that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.

Tabular results were produced by methodologists from the Business Survey Methods Division (BSMD) using the software that was developed for the Agriculture Division. Statistics Canada's standard rules for confidentiality were applied by using the random rounding method.

To reduce duplication and to ensure more uniform statistics, Statistics Canada has entered into an agreement under Section 12 of the Statistics Act, for the sharing of information from this survey with Agriculture and Agri-Food Canada, Environment Canada, the Prince Edward Island Department of Agriculture, the New Brunswick Department of Agriculture and Aquaculture, the Manitoba Department of Agriculture, Food and Rural Initiatives, Saskatchewan Agriculture and Food, Alberta Agriculture and Food, the British Columbia Ministry of Agriculture and Lands, and the Institut de la statistique du Québec. Under Section 12, Statistics Canada will not share any name, address or other identifying information, except for the case of the Institut de la Statistique du Québec. The information is required to be kept confidential and used only for statistical and research purposes. These various provincial data sharing partners will only have access to respondents within their respective province who agreed to share survey information.

Revisions and seasonal adjustment

This methodology does not apply to this survey.

Data accuracy

While considerable effort is made to ensure high standards throughout all stages of collection and processing, the resulting estimates are inevitably subject to a certain degree of error. These errors can be broken down into two major types: non-sampling and sampling.

Non-sampling error is not related to sampling and may occur for many reasons. For example, non-response is an important source of non-sampling error. Population coverage, differences in the interpretation of questions, incorrect information from respondents, and mistakes in recording, coding, and processing data are other examples of non-sampling errors.

Of the units contributing to the estimate, the response rate was 81.4%. Non-responding units, for example, no contacts and refusals, are dealt with by adjusting the initial sample weights.

The estimates published are based on a probability sample of farming operations. The potential error introduced by sampling can be estimated from the sample itself by using a statistical measure called the coefficient of variation (CV). Over repeated surveys, 95 times out of 100, the relative difference between a sample estimate and what should have been obtained from an enumeration of all farming operations with respect to the sample estimates would be less than twice the coefficient of variation. The sample estimate, plus or minus twice the CV is referred to as the confidence interval.

CVs were calculated for each estimate.

The qualities of CVs are rated as follows:
. Excellent 0.01% to 4.99%
. Very good 5.00% to 9.99%
. Good 10.00% to 14.99%
. Acceptable 15.00% to 24.99%
. Use with caution 25.00% to 34.99%
. Too unreliable to be published 35.00% or higher

Coefficients of variation for Agricultural Water Use Survey key variables are available in the publication "Agricultural Water Use Survey 2007, Methodology Report", catalogue no. 16-001-MWE2009008 (see the "Publications" sidebar above).