| Abstract: | Four Soviet hydrologists stress the usefulness of the water-balance principle in estimating the volume of water resources available to mankind. They carefully distinguish between the stable subsurface component of runoff, which has been mapped for the USSR at 1:5 million (and is now being mapped at 1:2.5 million) and the surface runoff, or flood, component. Measures are recommended to increase subsurface runoff at the expense of the surface component. These measures include autumn plowing to reduce sheetwash of snowmelt waters in spring, snowpack management in winter and windbreak planting. Other meliorative measures are irrigation and swamp drainage, both of which need to be placed on a more scientific basis with properly worked-out principles and norms. In discussing the world water-supply problem, the authors rule out recourse to new water sources, such as seawater desalination and glacier melting, and insist that mankind must preserve existing water resources by curbing the discharge of waste waters into natural bodies of water. The proposed recycling principles would increase consumptive use for water-supply needs, but would substantially reduce total withdrawals below the level that can be expected if present water-use practices continue to be followed. |
