DB46T 664-2025水生態(tài)監(jiān)測與評價技術(shù)規(guī)范

4646 5.3生境調(diào)查 5.4水環(huán)境監(jiān)測 5.5水資源監(jiān)測 6.2標(biāo)準(zhǔn)與分級 6.4整體評價 水生態(tài)監(jiān)測與評價技術(shù)規(guī)范HJ1172全國生態(tài)狀況調(diào)查評估3.13.2水環(huán)境質(zhì)量監(jiān)測waterenvironmental3.33.4和秋季（9-11月）分別開展一次。參照《河湖生態(tài)緩沖帶保護(hù)修復(fù)技術(shù)指南》（環(huán)辦水體函(2021〕558號）劃定河湖岸線生態(tài)緩沖），Ai=∑(xj×yj)·····································································(2)xj—二級指標(biāo)層第j個指標(biāo)的得分；yj—二級指標(biāo)層第j個指標(biāo)的權(quán)重；按照監(jiān)測單元為最小評價單元，根據(jù)評價單元的二級指標(biāo)按照綜合評價方法經(jīng)加權(quán)求和得到該點湖庫水生態(tài)環(huán)境質(zhì)量評價：按照湖庫所有評價單元水生態(tài)環(huán)境質(zhì)量評價指數(shù)的算術(shù)平均值進(jìn)行評優(yōu)、良好及中等評價單元比例＜75％，且較差、很差評價單較差、很差評價單元比例≥50％，且很差評價單元比例＜20%111···························································），····················································································································HI—香農(nóng)-維納多樣性指數(shù)；Ns—物種數(shù)。HI—香農(nóng)-維納多樣性指數(shù)；Ns—物種數(shù)；N—生物個體總數(shù)。河湖(庫)岸帶自然生態(tài)用地占比=················指以生長草本植物為主，覆蓋度在5％以上的····································································(B.7)采用河流縱向連通阻隔系數(shù)法，對不同類型的攔河建筑物賦予相應(yīng)的阻隔系數(shù)來表示其對河流的·······················································80＜zj≤10060＜zj≤8040＜zj≤6020＜zj≤400≤zj≤20·················································