In such an economy, the value of cr is critical to the potential for long run growth in this economy. If firms and households can take advantage of the increasingly abundant capital to invest in water-saving or reuse technologies, and if these technologies are sufficiently effective, then growth will proceed apace. This is indicative of an economy with a large value of a. Indeed, provided <j>\, even in the absence of water-saving technological change, the share of water in GDP will diminish over time as the economy becomes more and more water-efficient through capital-water substitution.