The issue of spatial scale in hydro-economic modeling of global and national food and water systems to address sustainable agriculture and natural resources management
K. Strzepek; A. McCluskey
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SANREM CRSP, Virginia Polytechnic Institute and State University
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Introduction: There are numerous models available that aim to address food and water policy at different spatial scales. The question to be asked of these models is “What is the importance of spatial scale on hydro-economic modeling used to address environmental and hunger policy questions?” The research set forth in this document aims to answer not only that question but also take it to another level and evaluate the importance of spatial scale and management on river basin modeling for global food production.
The first part of this research is provided in chapter 2 and evaluates the importance of spatial scale in hydro-economic modeling of global and national food and water systems to address environmental and hunger policy questions. Background to this research includes the driving force behind this research, a review of the existing models for policy, and a Summary of available global water and food models.
The International Food Policy Research Institute’s (IFPRI) IMPACT-Water model was evaluated at 2 different spatial scales (69 basins vs 281 basins) and the results from each version were compared to evaluate the importance of spatial scale on environment and hunger policies. Most indicators and results such as those related to hunger require comparison at the local/regional scale. In order to provide a detailed analysis comparing the results between the two different spatial scales of IMPACT-Water, three case studies at the regional scale were chosen to represent different hydro-climates and economic heterogeneity: Central Asia, Europe, Southern Sub-Saharan Africa.
The second part of this research is presented in chapter 4 and focuses on evaluating the importance of spatial scale and management on river basin modeling for global food production. Background to this research includes previous studies on scale, examples of global river basin modeling, and basin characteristics used to assess the importance of a basin representation’s spatial scale. Case studies for this analysis include a theoretical analysis on the sequence of supply, storage and demands along a river, and four river basin case studies (Missouri River Basin, Senegal River Basin, Yellow River Basin, Volta River Basin).
Findings from these case studies were applied to 2 different global river basin representations; one with 69 basins and another with 126 basins and conclusions were made about the importance of spatial scale and management on river basin modeling for global food production.
Conclusions from both parts of this research are presented in chapter 5 and can be summarized by the following key findings:
– Spatial scale does have an impact on model results used to inform environment and hunger policy.
– Impacts are stronger in regions of economic and hydro-climate heterogeneity. – One risks the possibility of overestimating available water in basin representations where rivers are in parallel which could lead to overestimating the potential of global irrigated agriculture.
– Properly representing the sequence of supply, storage, and demand is very important. – Recognizing the level of a basin’s infrastructure is important. – Modeling the correct management may be a significant issue if a basin is heavily managed.