Although there is a very large inequality in the volume of freshwater availability between the two country sub-groups, the impact on trade is much smaller due to a relatively low elasticity. Policy conclusions for aid for trade investments should be drawn by comparing these outcomes with the cost and feasibility of actually achieving the improvements being discussed. The econometric approach, while suffering from data limitations, serves to highlight the relative importance of different constraints to agricultural development in developing countries, and the need to take into account country-specific circumstances in designing aid for trade programmes.