粤港澳大湾区金山湖流域水质变化规律

Water quality variations of Jinshan Lake Basin in Guangdong,Hong Kong and Macao Great Bay Area

针对粤港澳大湾区城市河湖水质变化规律复杂、机制不确定等问题,建立了金山湖流域耦合陆面单元、河网、湖泊等不同尺度的“空地水”一体化模型,模拟了2017年水量、COD质量浓度和TP质量浓度的变化规律,3个指标的相对误差均在15%以内。模型模拟结果表明,金山湖流域内水质超标严重,枯水期相对丰水期水质较差,典型枯水月12月湖区逐日劣Ⅴ类面积占比大于96.66%;年内中小雨共出现31次,在中小雨后的1~3 d易出现水质下降现象;大雨共出现8次,在大雨后水质得到改善;金山湖流域水质指标浓度与耕地、农村居民点面积呈显著正相关关系,与林地面积呈显著负相关,人类活动强的区域水质相对较差。

Aiming at the complicated variations of water quality and uncertain change mechanism of urban rivers and lakes in Guangdong,Hong Kong and Macao Great Bay Area,the“air-ground-water”integrated model of the Jinshan Lake Basin coupling different scales of land surface unit,river network and lake was established.The variation laws of water volume,COD mass concentration and TP mass concentration in 2017 were simulated,and the relative errors of the three indexes were within 15%.The simulation results show that the water quality in the Jinshan Lake Basin exceeds the standard seriously,and the water quality in the dry season is worse than that in the wet season.In December of the typical dry month,proportion of area with daily water quality inferior to class V standard is more than 96.66%.There are 31 times of moderate and light rain in the year,and the water quality in the basin tends to decline in 1-3 d after moderate and light rain.There are 8 times of heavy rain in the year,after which the water quality is improved.The concentration of water quality index in the Jinshan Lake Basin has a significant positive correlation with cultivated land and rural residential area,and a significant negative correlation with forest land area,indicating that the water quality in areas with strong human activities is relatively poor.