美國還有9.1萬個水壩,中國有9.8萬個, 歐洲國家有1.2million 水利設施。 非洲據說有1000個左右大壩

There are over 91,000 dams in the US, with some estimates reaching over 500,000, many of which provide benefits like flood control, water supply, and hydroelectric power. Despite the large number of dams, many are aging, deteriorating, and no longer serve their original purpose, leading to safety hazards and environmental concerns that prompt ongoing efforts to repair or remove them. 
 
Why we still need dams
  • Flood control: Dams help prevent flooding by holding back excess water and releasing it in a controlled manner.
  • Water supply: They act as reservoirs, storing water for drinking, agriculture, and industrial use.
  • Hydropower: Many dams generate electricity through turbines, providing a source of renewable energy.
  • Irrigation: Dams supply water for agricultural irrigation, which is crucial in many parts of the country.
  • Navigation: They create or maintain navigable waterways for commercial and recreational boats.
  • Recreation: The reservoirs created by dams are often used for recreational activities like boating and fishing. 

 

China has over 98,000 dams, and they are still needed for hydropower, flood control, and water security, though climate change and dam management present new challenges. These dams are crucial for generating electricity, providing water for agriculture and industry, and preventing catastrophic floods, which have historically caused immense damage along major rivers. However, the construction of numerous dams, particularly the mega-dams, has had negative environmental impacts. 

 

 

 

here are likely between 600 and 800 large dams in Africa, though a precise number is difficult to confirm. Dams are still needed for crucial functions like irrigation, providing clean drinking water, and generating hydropower, which is a key source of renewable energy for many countries. However, building dams is often controversial due to negative impacts like development-induced poverty, social displacement, and inequitable distribution of benefits. 
 
How many dams are in Africa?
  • The exact number is not definitively known, but estimates for large dams and reservoirs range from 600 to 800.
  • One source states there are over 1,270 large dams in Africa, but this number may be less up-to-date or use a different definition. 

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大壩數量也是國家實力的指標之一。說大壩破壞環境的人就像說建房子破壞環境一樣,他們應該住山洞裏,那樣最保護環境。 -為人父- 給 為人父 發送悄悄話 為人父 的博客首頁 (167 bytes) () 11/11/2025 postreply 13:43:52

要絕對環境保護,可以考慮自戕, -大洋bridge- 給 大洋bridge 發送悄悄話 大洋bridge 的博客首頁 (0 bytes) () 11/11/2025 postreply 13:48:20

根據西方學者的數據,人是最大的環境破壞者。沒人了,地球生態就會恢複如初。 -為人父- 給 為人父 發送悄悄話 為人父 的博客首頁 (321 bytes) () 11/11/2025 postreply 13:55:08

AOC說現在牛放屁都是問題。climate change是主黨的主題。有問題可以請教他們 -Uusequery- 給 Uusequery 發送悄悄話 (167 bytes) () 11/11/2025 postreply 13:55:48

我覺得你們的觀點和民主黨差不多,都反對建大壩,說大壩破壞環境。 -為人父- 給 為人父 發送悄悄話 為人父 的博客首頁 (167 bytes) () 11/11/2025 postreply 14:04:17

幾時說到反對建大壩,隻是提到美國近年來在拆大壩。說說民主黨如何反對建大壩?美國近年討論過修水壩? -Uusequery- 給 Uusequery 發送悄悄話 (325 bytes) () 11/11/2025 postreply 14:08:01

拆不拆是有經濟考量的,美國的大壩大部分都是老化嚴重,有的早該拆卻因為沒錢拆不了,直到被洪水衝垮反而成了比較省錢的辦法。 -dakinglaile- 給 dakinglaile 發送悄悄話 dakinglaile 的博客首頁 (0 bytes) () 11/11/2025 postreply 14:21:04

每條河流上能建水電站的壩址是固定有數的,美國從建國到現在,能建設且有經濟效益的壩址早都建了,所以基本沒有新建的需要。 -天青水藍- 給 天青水藍 發送悄悄話 天青水藍 的博客首頁 (0 bytes) () 11/11/2025 postreply 14:22:55

現在拆除的都是年代比較久遠,年久失修有潰壩危險的,如果在洪水中被衝垮,會給下遊帶來危險,主動拆除可以避免這種危險 -天青水藍- 給 天青水藍 發送悄悄話 天青水藍 的博客首頁 (0 bytes) () 11/11/2025 postreply 14:25:05

明州前兩年被衝垮的一個就是因為沒錢拆才拖到洪水衝的。 -dakinglaile- 給 dakinglaile 發送悄悄話 dakinglaile 的博客首頁 (0 bytes) () 11/11/2025 postreply 14:36:20

不建的理由就更多了。畢竟過去百年裏美國先輩們早就把能建的都建了一遍了。現在環保要求和建造費用這麽高,想建個新的難如登天。 -dakinglaile- 給 dakinglaile 發送悄悄話 dakinglaile 的博客首頁 (0 bytes) () 11/11/2025 postreply 14:23:29

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