为了保持人类社会经济可持续发展,在某一地域或范围,水资源开发(取水量)应控制在一定的安全极限内。目前国内外有关人士多认为,这个安全极限大体是当地水资源总量的20%~40%。如果超出这个安全极限,通常由于水资源的时空分布不均、农业用水的季节性较强而城市与工业供水保证率又 In order to maintain the sustainable development of human society and economy, in a certain area or range, water resources development (water withdrawal) should be controlled within certain safety limits. At present, many people at home and abroad think that this safety limit is roughly 20% to 40% of the total amount of local water resources. If beyond this safety limit, usually due to the uneven distribution of water resources in time and space, agricultural seasonal strong and urban and industrial water supply guarantee rate