A Linear Programming Optimization of Water Resource Management with Virtual Water through Global Trade: A Case Study of Germany

The embodied water in globally traded goods is an increasing share of water consumption. An application of linear programming is presented to optimize Germany's crop production and trade. The 47 primary crops considered account for 38% of the world's total crop water use (1997–2001). Germany's baseline (1997–2001 average) production of primary crops resulted in the use of 41.5 Gm³/yr domestic freshwater and 9.6 Mha/yr of domestic land; of this, 19% of water and 18% of land were used for exports. From imports, there was an 18% water and 23% land dependency on foreign nations. For Germany to be self-sufficient (producing all primary crops domestically) it would require 11.19 Mha/yr (∼95% of total arable land) and 47.7 Gm³/yr water (∼15% increase from baseline). The minimum water footprint for German consumption of primary crops is 46.3 Gm³/yr; resulting in a 16% water dependency on imports at a cost of $1.53 billion/yr.