我国北方闸控河流水质变化特征研究

基于2013年潮白新河(天津段)水体COD、NH+4-N、TN和TP的监测数据,通过研究影响研究区水质变化的主要因素,按照农作物的生长周期(将全年分为播种期、生长期和收获期)分析我国北方闸控河流水质时间变化特征和空间变化特征。结果表明,农业面源污染是该流域的主要污染源;在气候、闸坝调度和污染来源的共同作用下,各监控断面水质变化较大,各监测指标值存在明显时空差异。其中,COD和TN污染负荷由大到小为播种期、收获期、生长期,NH+4-N和TP污染负荷由大到小为播种期、生长期、收获期。不同时段水质的空间分析表明,河流上游NH+4-N、TN和TP污染负荷偏高,河流中、下游COD污染较严重。因此,在分析北方闸控河流水质状况时,应综合考虑影响水质的主要因素,分时段、分河段进行水质评价。

On the variation characteristics of water quality in dammed river in Northern China

To solve the water resources shortage and control the serious water environment pollution in Northern China,this paper has chosen Tianjin section of Chaobaixin River (in the north of Haihe Basin) as the study object to investigate the status and variation characteristics of the water quality during 2013.Based on the monitoring data of the chemical oxygen demand (COD),ammonia nitrogen (NH4+-N),total nitrogen (TN) and total phosphorus (TP) concentration collected at the five monitoring sections and the three main influential factors of water quality,we have made an analysis of the spatial and temporal variation features of the water quality in the aforementioned section of the dammed river.In proceeding with our study,we have divided the weather and climatic changing situation of a full year into three different seasons for analyzing the water quality,that is,the planting season,the growing season and the harvest season in correspondence with the crop growing cycle and the climatic temperature variation.The results of our investigation show that the non-point source agricultural pollution tends to be the main pollution source for the study area.In the said area,the whole annualround variation of water quality in the different monitoring sections and seasons proves quite great and therefore significantly intense,that is to say,there exists remarkable spatial-temporal variation of water quality due to the climate change,the dam operations and the pollution sources distribution.And,statistically,the pollution load of COD and TN can be shown in a descending order,i.e.the planting season ＞ the harvest season ＞ the growing season.In terms of the pollution load of NH4+-N and TP,the order should be:the planting season ＞ the growing season ＞ the harvest season.The spatial analysis of the water quality in different periods indicates that the pollution load of NH4+-N,TN and TP turns to be generally heavier in the upper reaches of the river,with the pollution of COD in the middle and lower reaches being serious.Therefore,it can be concluded that it is necessary to avoid treating the monitoring data as the mere standard for the analysis of the variation characteristics of water quality.Rather,it is necessary to pay more attention to the effects of the climatic change,the pollution sources distribution and some other influential factors on the water quality of the dammed river,in addition to conducting a more strict water quality management and control for the said different sections af the river and the different periods of a year circle.