基于遥感数据的大汶河流域济南段水体面积变化分析及生态流量评价

Analysis of Water Body area Changes and Ecological Flow Evaluation in the Jinan Section of the Dawen River Basin Based on Remote Sensing Data

气候变化与人类活动对大汶河生态健康影响日益显著,为维持河流生态健康的稳定性,开展生态流量评价至关重要。以大汶河流域济南段为研究范围,采用多源遥感资料提取水体面积信息,由水体面积与实测流量构建拟合方程,推求基本生态流量对应的生态水体面积,开展基于遥感数据的生态流量评价。研究结果显示:1985-2021年大汶河流域济南段水体面积41.84 km^(2),水体面积呈增加趋势,其中季节性水体占32%,永久性水体占68%。6种水体指数中EWI、NDWI适用于大汶河流域济南段,精度达到90%。由线性拟合方程推求,陈北、马小庄流域生态水体面积分别为13.98 km^(2)、18.49 km^(2)。1985-2021生态流量保障率分别为65%、42%。受自然因素与人为因素影响,2004年前后生态流量保障率变化明显,分别由43%、7%提高到83%、73%,至2020年均达到100%。交叉小波与小波相干谱分析表明,水体面积与气候因素中降水、平均湿度呈正相关,与平均风速呈负相关,与平均温度的相干性不显著,降水与平均湿度是影响水体面积变化的主要因素。土地利用因素中,水体面积变化主要受耕地、草地面积影响,呈负相关。由不同水体面积比例,确定流域内雪野水库生态水体面积10.82 km^(2),生态水位228.97 m,生态库容1.02亿m^(3)。研究成果可为大汶河流域生态流量评价、监管与调度提供技术支撑。

Climate change and human activities have increasingly significant impacts on the ecological health of the Dawen River.To main⁃tain the stability of river ecological health,it is crucial to carry out ecological flow evaluation.This study focuses on the the Jinan section of the Dawen River Basin,utilizing multi-source remote sensing data to extract water body area information.A fitting equation is constructed from the water body area and the measured flow,to determine the ecological water body area corresponding to the basic ecological flow.Ecological flow evaluation is then conducted based on remote sensing data.Research results show that,from 1985 to 2021,the water body area of the Jinan section in the Dawen River Basin is 41.84 km^(2),and the water body area shows an increasing trend,of which seasonal water bodies account for 32%and permanent water bodies account for 68%.Among the six water body indices,EWI and NDWI are suitable for the Jinan section of the Dawen River basin,with an accuracy of 90%.Through linear fitting analysis,the ecological water body areas of the Chenbei and Maxiaozhuang watersheds are 13.98 km^(2) and 18.49 km^(2) respectively.The ecological flow guarantee rates from 1985 to 2021 are 65%and 42%respectively.Affected by natural factors and human factors,significant changes in the ecological flow guarantee rates were observed around 2004,increasing from 43%and 7%to 83%and 73%respectively,and reach 100%by 2020.Cross wavelet and wavelet coherence spectrum analysis results show that the water body area is positively correlated with the climate factors of precipitation and average humidity,negatively correlated with average wind speed,and has no significant coherence with average temperature.Precipitation and average humidi⁃ty are the main factors affecting changes in the water body area.Among land use factors,changes in water body area are mainly affected by the area of cultivated land and grassland,showing a negative correlation.Based on the different water body areas ratio in the basin,it is de⁃termined that the ecological water body area of Xueye Reservoir is 10.82 km^(2),the ecological water level is 228.97 m and the ecological stor⁃age capacity is 102 million m^(3).The research results can provide technical support for ecological flow evaluation,supervision and dispatch in the Dawen River Basin.