求翻译：湖南地势呈东、 西、 南三面高、 北面低的马蹄形状盆地。三湘四水的面源污染——农田化肥、 生活污水、畜禽粪便、 工业废水、 矿物燃料等等， 长年累月， 随流水顺势而下。而三峡大坝的耸立， 洞庭湖与长江换 水的频率和强度大幅度降低， 这些污染物没能像以前一样随滚滚长江漂移东海， 而是集结于此。近年来 ， 洞庭湖夏季秋天温度很高,日照很强.的频率和强度大幅度降低， 这些污染物没能像以前是什么意思？

Hunan terrain was on three sides, east, west, south and north of the horseshoe shape of the basin. Sanxiang four-point source pollution of water - irrigation and fertilizer, sewage, animal manure, industrial wastewater, mineral fuels, etc., over many years, with the water flow under. The Three Gorge

Hunan Province is lying south east, west, north, and 3 high-low horseshoe-shaped basin. Hunan Province 3 OF THE 4 water-source pollution - farm fertilizers, sewage, manure, wastewater, and fossil fuels, and so on, all year long, with the sequential homeopathy. And it stands out of the Three Gorges D