摘要
为揭示合肥地区不同类型源头溪流暂态存储能力及氮磷吸收滞留的基本特征,在城区和城郊筛选4条典型源头溪流,并以NH4Cl、KH2PO4为添加营养盐,以Na Cl为保守型示踪剂,开展现场示踪实验.在此基础上,利用OTIS模型水文参数(D、A、As和α),计算暂态存储指标(Ts、Tc、Ls、Rh和F200med),进而开展暂态存储能力分析,并以NH+4-N和SRP一阶吸收系数(λ、λs)解析氮磷滞留特征.结果表明:4条溪流水体的α值均处于10-4~10-3数量级;各溪流Tc基本都显著超过Ts,意味着这些溪流水体溶质滞留效应主要来自主渠道流动水体,而不是暂态存储区;根据Tc、Ts、Ls和Rh等指标,得到各源头溪流暂态存储能力排序为:二十埠河二级支流>二十埠河一级支流>十五里河源头段>关镇河支渠;4条源头溪流主渠道流动水体与暂态存储区的NH+4-N、SRP滞留特征存在很大的差异,并且二十埠河一、二级支流和十五里河均不同程度出现λ-NH+4、λs-NH+4为负值的现象,意味着这些水体对于NH+4-N既具有短期存储作用,也起着'源'的作用.
To investigate the capacity of transient storage and characteristics of nitrogen and phosphorus retention of different sorts of headwater streams in Hefei,four typical headstreams were chosen in urban and suburban areas. A series of instantaneous tracer experiments were carried out on the chosen stream reaches by taking NH+4Cl and KH2PO4 as nutrient additions and Na Cl as conservative tracer. Transient storage metrics( i. e. Ts,Tc,Ls,Rhand F200med) were estimated according to the hydrological parameters( i. e. D,A,Asand α) in OTIS model to explore the capacity of transient storage,and first-order uptake rates of NH+4-N and SRP arising from OTIS model calculation were also used to delineate the characteristics of nitrogen and phosphorus retention for above headstreams. The results showed that the values of exchange coefficient α for the four headstreams were all in the order of magnitude of 10- 4~ 10- 3. Nearly all the Tcvalues were remarkably higher than that of Ts,suggesting that the solute retention effect should be dominated by main channel rather than transient storage zone for the four streams. After considering all these metrics of Ts,Tc,Lsand Rh,the order of transient storage capacity were obtained as the second-order stream of Ershibuhe River > the first-order stream of Ershibuhe River > the headwater stream of Shiwulihe River> Guanzhenhe Creek. Great difference in the NH+4-N and SRP retention between the main channel running water and transient storage zone was found among the four studied streams. Moreover,some negative values of λ-NH+4and λs-NH+4 were obtained in the first-and second-order streams of Ershibuhe River and the headstream of Shiwulihe River,implying that these stream reaches acted as a short-term storage zone and nutrient source for NH+4-N.
出处
《环境科学学报》
CAS
CSCD
北大核心
2015年第1期128-136,共9页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.51179042)~~
关键词
源头溪流
OTIS模型
水文参数
暂态存储指标
氮磷滞留
headwater stream
OTIS model
hydrological parameters
transient storage metrics
nitrogen and phosphorus retention
