Is Small Better? A Comparison of the Effect of Large and Small Dams on Cropland Productivity in South Africa
研究了南非大型和小型灌溉水坝对农田生产力的不同影响，发现大型水坝虽能提升下游生产力，但会抑制周边农田，而小型水坝的正面影响可被大型水坝增强，成本效益分析显示小型水坝可能更可行。
This study estimates and compares the \n effects of small and large irrigation dams on cropland \n productivity in South Africa. To this end, a panel data set \n of South African river basins is constructed. The \n econometric analysis reveals that although large dams \n increase cropland productivity downstream, they have a \n negative effect on cropland within the vicinity. However, \n their existence can enhance the relatively small positive \n impact of local small dams. Although a cost-benefit analysis \n of irrigation benefits shows that small dams may be more \n viable than large ones, large dams can play a potentially \n important role within a system of both types of dams.