Ontario Grain Farmer March 2021

24 Water is a precious resource. The success of farm businesses and the health of our families depend on having a clean and abundant supply. Historically, agricultural technology has allowed us to manipulate the quantity and quality of water supplies to increase productivity. Today, this continues, with new technologies and a better understanding of natural processes. This article is the sixth in a series focusing on modern management of water for grain farms. Go to www.ontariograinfarmer.ca for more information and previous articles. PORTIONS OF ONTARIO grain production areas have suffered from significant droughts in three of the last 10 years (2012, 2016, and 2020). With improved genetics and significant investments in crop inputs, some farmers are looking to irrigation as a way to eliminate drought related losses and optimize crop production. When we consider an average of all the grain production areas across Ontario, irrigation is not economically beneficial. However, some soils, locations, and business constraints may make irrigation attractive to some grain farmers. If you are considering investing in irrigation, this article will walk through the main considerations: water supply, permitting, equipment, operating costs, and labour. Planning and developing an irrigation water supply involves considering the source, costs, convenience, reliability, environmental impacts, and permitting requirements. Options include wells, lakes, rivers/streams and ponds, including landowner constructed ponds. The first step is to estimate how much water will be needed and at what flow rate; then match the demands to a water source which can sustainability provide that volume and flow of water. WATER NEEDS Current Ontario grain corn production could benefit from three applications of 25mm of irrigation in dry summers (total of 75mm/ three inches). The flow rate needed is commonly calculated by multiplying five U.S. gallons per minute (gpm) for every acre irrigated. So, for a 100 acre parcel, you would require a source that can provide 500 U.S. gpm and Water management IRRIGATION CASE STUDY Rebecca Shortt Agronomy Activity Agency Act or regulation Digging (movement of fill), Placement of fill or construction in Flood Plain Conservation Authority Conservation Authorities Act Removal of fill (i.e. during reservoir construction) MNRF Aggregate Resources Act Activities in and around municipal drains Municipality Drainage Act In-stream construction, digging, holding back water, diverting or forwarding water MNRF Lakes and Rivers Improvement Act Using water for irrigation >50,000L MECP Ontario Water Resources Act (Permit to Take Water) Using water during droughts Conservation Authority, MNRF Ontario Low Water Response (voluntary program) TABLE 1: REGULATORY CONSIDERATIONS. a seasonal total of at least eight million U.S. gallons (31 million litres). Will your water source be available in times of drought and meet your needs without interfering with other water takers or impacting the natural environment? Do you need a reservoir or holding pond in combination with another water source? For more information on developing irrigation reservoirs see the Fact Sheet: www.omafra.gov . on.ca/english/engineer/facts/16-009.htm. Your water supply must be on the farm or nearby so that the distance and vertical lift between it and your irrigation system are minimized; this will minimize the pumping and infrastructure costs. It is important to consider the environmental implications associated with taking water. Taking large amounts of water from a well may cause reduced water in nearby wetlands, streams, or other farm wells. Taking large amounts of water from a small stream can have a major impact on the stream flow. It is illegal to restrict stream flow either by pumping or by constructing a temporary dam (such as with sandbags) to create a pool for irrigation without the necessary permits. Table 1 shows a list of some of the relevant regulations that apply to water supply development and use. PERMITS A Permit to Take Water (PTTW) from the Ontario Ministry of Environment, Conservation and Parks (MECP) is required for any irrigation taking of more than 50,000 L/day (that is ~0.5 acres irrigated with one inch of water). The PTTW program helps to make sure water is safeguarded and shared fairly among all water users, while maintaining necessary flows to protect the environment. A permit is required even if the taking only occurs one day per year. It applies to all water sources used for irrigation, such as wells, streams, lakes, and ponds, and includes water supplies