一、引洪淤灌的必要性西拉木伦河位于昭盟北部,是西辽河上游主要支流之一,两岸属半干旱草原区有草原3400万亩,其中缺水草原近2000万亩,由于干旱缺水,风沙大,加以过度放牧,造成草场严重退化,现已有退化草场1850万亩,其中严重退化的草场1320万亩,大部分退化草场为沙地和丘陵草场。 First, the need to divert flood silt Westlammun River is located in northern Zhao League, is one of the main tributaries of the upper reaches of the West Liaohe River, the semi-arid prairie area is a grassland 3400 acres, of which nearly 2,000 acres of waterlogged grasslands, due to Drought, lack of water, large sandstorms and overgrazing cause severe degradation of pastures. There are now 18.5 million mu of degraded pastures, of which 13.2 million mu are seriously degraded. Most of the degraded pastures are sandy and hilly pastures.