Integrated framework model for water productivity calculations “WP-Calc”: theoretical basics and evaluation
Improving agriculture and irrigation management needs to be based on more efficient and profitable use of water to produce more crops. “Water productivity” is a simple concept reflects the objectives of producing more food, income, livelihood and ecological benefits with less social and environmental cost per unit of water consumed (Molden et al., 2010). Water productivity could be determined for spatial levels; single crop, farms, irrigation zones, agricultural districts, national level, and global level. Increasing water productivity, as essential objective for irrigated agriculture in arid regions, could be achieved by applying less water to produce the same yield, or applying the same amount of the water to have higher yield (Descheemaeker et al., 2013). Water productivity analysis helps to understand and identify where and when water can be saved in an irrigation zone or system, by understanding water and salts movement and balance (Pedras and Pereira, 2006), which could give good implications of the sustainability of the irrigation practices, by investigating the short and/or long term impacts on soil and water resources. For a given watershed, irrigation requires an integrated planning including both crop level and watershed level, to avoid the planning and management gaps between the two levels. It should consider the different biophysical and hydraulic parameters of the system, under different spatial and temporal levels of analysis. This integrated concept of irrigation planning is no longer a difficult challenge, that at the recent decades the integrated irrigation management is improved as a result of the improvement in data collection and analysis tools, decision support tools, digital technology, communication tools, and communities’ awareness (Rinaldi and Ubaldo, 2007).