Metro Vancouver Agricultural Water Forum: British Columbia’s Agriculture Water Calculator – a presentation by Stephanie Tam, Water Management Engineer with Ministry of Agriculture

TEST DRIVE IT! The Water Licensing Calculator is available at

TEST DRIVE IT! The Water Licensing Calculator is available at

Licensing Groundwater Use under BC’s new Water Sustainability Act

“Following a request from the agricultural industry, the Ministry of Agriculture (AGRI) partnered with the Ministry of Environment (MOE), Partnership for Water Sustainability in BC (PWSBC), and Okanagan Basin Water Board (OBWB) to develop an online tool called the BC stephanie-tam_bc-ministry-of-ag_120pAgriculture Water Calculator to assist with water licence applications,” stated Stephanie Tam, Water Management Engineer with the BC Ministry of Agriculture.

“This tool calculates irrigation and livestock water requirements to assist agricultural producers in determining how much water to apply for in their water licence applications, for both surface water and groundwater.”

“Since there are about 20,000 non-domestic wells that will be required to be licensed by March 1, 2019 under the Water Sustainability Act (WSA), the Ministry of Forests, Lands and Natural Resource Operations (FLNRO) also uses this tool to assess groundwater licence applications more efficiently.”

“The tool was launched in March 2016, and is publicly available at:”


Application of Agriculture Water Demand Model

“The database for the Water Calculator is generated by the Agriculture Water Demand Model (AWDM). This tool calculates water demand using downscaled climate data on a 500 m by 500 m grid. The climate data uses information Digital Elevation Model (DEM)  that takes into account a number of parameters such as elevation, latitude and longitude, slope and other factors.”

“Combined with irrigation efficiency and soil texture information, water demand can be calculated for each grid cell using forage as a base crop, sprinkler as a base irrigation system, and sandy loam as a base soil texture.”

“Factors are applied to determine the water requirement for other crops and soil conditions.”

“For this calculator, ten years (2001 to 2010) of historical climate observations dataset were modelled to produce annual irrigation water demands and 10-day peak evapotranspiration.”

“The irrigation water demand results were averaged over 10 years as the “new normal” of water requirements, and serve as inputs in the BC Agriculture Water Calculator. For peak evapotranspiration data in this tool, the maximum 10-day value from the 10-year period was used.”

To Learn More:

Download BC Agriculture Water Calculator to view a PDF copy of the PowerPoint presentation by Stephanie Tam, Water Management Engineer with the BC Ministry of Agriculture. Her focus is primarily on irrigation and drainage, weather station network, and development of online tools for irrigation management. In the past two years, she has been collaborating with the Ministry of Environment developing regulations under the Water Sustainability Act.