This is explained by the fact that design and implementation of regional policies relies heavily on sub-national governments. Obstacles to coherence between water and other policy areas in OECD countries (cont.) Besides, overlapping, unclear and nonexistent allocation of responsibilities is more problematic when it comes to co-ordinating water and regional development policies than for the energy and agricultural sectors, for several reasons. First, OECD countries have generally set up more co-ordination mechanisms between water, energy and agricultural policies than in the areas of regional development and spatial planning. Second, water and energy policies are frequently led within an environment ministry and water resources management are often handled, at least in part, within a ministry of agriculture.