试论曹娥江上游低山丘陵区的水土流失及其治理

曹娥江上游地区，由于受自然条件和人类活动的影响，导致严重的水土流失，成为浙江省水土流失最为严重的河流。水土流失破坏了生态平衡，威胁着流域内人民的生产和生活安全，极需治理。

ON THE SOIL EROSION AND ITS CONTROL IN AREAS OF LOW MOUNTAINS AND HILLS IN THE UPPER CAO'E RIVER

: The areas of low mountains and hills in the upperreaches of the Cao'e River, the largest fributary of the Qiantang in its lower reaches, are those where soil erosion has become the most serious problem in Zhejiang Province. The average silt content of the Chengtan River, its main stream, has amounted to 0.2-0.5kg/m3 for years, and the average erosion modulus to 405 t/km2. The worsened soil erosion, in accelerating the barrenness of the soil, the continual silting of reservoirs and the river course, and the disastrous aggravation of floods and wa- terlogging, lead to the over-all deterioration of the naturaI environment. The soil erosion is mainly effected by such physiographical factors as rock character. soil, geomorphology, and rainfall, combined with such artificial factors as deforestation, land recla- mation on steep slopes, etc. To bring the soil erosion under permanent control, biological measures should be taken in combination with engineering ones, namely, to put stress on free-planting and afforestation, fanse gullies and ravines by means of such a method as applicable to the whole valley, put an end to land reclamation on the slopes, and reform the cultivated slope land. The soil erosion in the upper Cao'e has been a deep concern of the people, and a series of measures, taken in recent years in particular. have achieved certain positive results. soil ero- sion, owing to various reasons, however, is still one of the serious problems that demands a prompt solution.