河流水质与土地利用及河道结构特征关系的对比分析

Correlations analysis of river water quality with land use and river structure

为了比较河道两侧土地利用和河道结构特征对河流水质的影响,以瓯江丽水段为研究对象,在半径依次为100、200、…、900 m,共9个观测尺度上,运用广义线性模型分析了土地利用方式和河道结构特征对几种水质指标的影响。结果表明:研究区内各个水质指标沿河段的空间变化程度不同,悬浮物和硝态氮的浓度变化较小,其余指标变幅均较大。河道两侧的土地利用方式和河道结构特征对于水质表现出不同的解释能力和作用强度,河道两侧土地利用方式中,农田对悬浮物和正磷酸盐、聚落用地和林地对总磷等有相对较高的方差贡献率,而河道结构特征中,滩地对总氮和氨氮、采砂坑对硝态氮和氨氮的解释能力较高。

To comprehensively understand the response of water quality to riparian land use pattern and streambed structure,we examined the correlation between seven water quality indicators and seven landscape/environmental variables in a section of Oujiang River. Correlation analysis was conducted at nine spatial scales from 100 m to 900 m using generalized linear models. The results showed that the water quality indicators,except for suspended solids and nitrate nitrogen,generally varied significantly by spatial location. Among land use types,cropland had relatively high explanatory power for concentration of suspended solids and orthophosphate in the river; total phosphorus and ammonia nitrogen was mostly explained by beach; while nitrate nitrogen was correlated with sandpit. Overall,riparian land use pattern and streambed structure had different explanatory power for phosphorus and nitrogen in the water. Nitrogen in the river was mostly influenced by streambed structure,and concentration of phosphorus was mainly determined by riparian land use pattern.