sand and gravel extraction

基本解釋

Besides the storm tide impact, the main causes for coastal erosion are due to the continued decrease of material supply and manual extraction of sand and gravel.
海岸侵蝕的原因除風(fēng)暴潮影響外，主要是海岸帶物質(zhì)補(bǔ)給來(lái)源持續(xù)減少和人工採(cǎi)挖砂石。
journal.geomech.ac.cn
The variations of flow pattern cause headwater erosion, and the sand gravel extraction will result in comprehensive adjustment of riverbed , affecting riverbed stability.
水流流態(tài)變化引起溯源沖刷，進(jìn)而導(dǎo)致河牀全麪調(diào)整，影響河牀穩(wěn)定。

Major activities in the area are agriculture, forest management, sand and gravel extraction, industry (diverse types), and ecotourism.
UNESCO: EDUCATION