Floodplain connection buffers seasonal changes in urban stream water quality
Floodplain connection buffers seasonal changes in urban stream water quality
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洪泛区连接缓冲了城市河流水质的季节性变化
DOI：
10.1002/hyp.10210
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发表时间：
2015
影响因子：
3.2
通讯作者：
L. Lautz
中科院分区：
文献类型：
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作者：
S. Ledford;L. Lautz
美国东北部的城市河流在冬季有大量的道路盐输入，无机氮的非点源增加，营养物质的短期和永久储存减少。恢复活动，重新建立溪流和河岸环境之间的联系，可能是有效的改善城市溪流水质。Meadowbrook Creek是纽约州锡拉丘兹的一级河流，它为探索河流-洪泛区连接的影响提供了独特的环境，因为它沿着负的城市化梯度流动，从渠化和装甲源头流向具有河岸含水层的广阔植被洪泛区。在这项研究中，我们调查了如何重新连接到地下水和引进河岸植被影响城市地表水化学的溪流水化学从2012年5月至2013年6月的双周纵向调查。我们使用多种方法测量了沿着小溪的地下水排放率。氯化物浓度在上游，断开河段的影响，道路盐在融雪事件的排放，范围从161.2至1440毫克/升。由于地下水排放的缓冲作用，下游相连河段的氯化物浓度随时间变化较小，范围为252.0至1049 mg/l，因为地下水氯化物浓度范围为84.0至655.4 mg/l。在夏季，有很少或没有硝酸盐在断开的河段，因为有限的来源和高初级生产力，但浓度达到1毫克N/升以上的连接河段，因为河岸植被的存在。在冬季，当温度降至冰点以下时，断开河段的硝酸盐浓度增加到0.58 mg N/l，但仍低于连接河段，平均为0.88 mg N/l。恢复洪泛区连接的城市溪流恢复项目可能会通过在冬季溢出事件期间储存高盐分道路径流并全年排放这些水来影响水质，从而减弱氯化物的季节性波动。与以前的研究结果相反，我们观察到，洪泛区连接和河岸植被可能会改变硝酸盐的来源和汇，硝酸盐浓度增加纵向连接的城市河流。版权所有© 2014约翰威利父子有限公司.
Urban streams in the Northeastern United States have large road salt inputs during the winter, increased nonpoint sources of inorganic nitrogen and decreased short‐term and permanent storage of nutrients. Restoration activities that re‐establish connection between streams and riparian environments may be effective for improving urban stream water quality. Meadowbrook Creek, a first‐order stream in Syracuse, NY, provides a unique setting to explore impacts of stream–floodplain connection because it flows along a negative urbanization gradient, from channelized and armoured headwaters to a broad, vegetated floodplain with a riparian aquifer. In this study, we investigated how reconnection to groundwater and introduction of riparian vegetation impacted urban surface water chemistry by making biweekly longitudinal surveys of stream water chemistry in the creek from May 2012 until June 2013. We used multiple methods to measure groundwater discharge rates along the creek. Chloride concentrations in the upstream, disconnected reach were influenced by discharge of road salt during snow melt events and ranged from 161.2 to 1440 mg/l. Chloride concentrations in the downstream, connected reach had less temporal variation, ranging from 252.0 to 1049 mg/l, because of buffering by groundwater discharge, as groundwater chloride concentrations ranged from 84.0 to 655.4 mg/l. In the summer, there was little to no nitrate in the disconnected reach because of limited sources and high primary productivity, but concentrations reached over 1 mg N/l in the connected reach because of the presence of riparian vegetation. During the winter, when temperatures fell below freezing, nitrate concentrations in the disconnected reach increased to 0.58 mg N/l but were still lower than the connected reach, which averaged 0.88 mg N/l. Urban stream restoration projects that restore floodplain connection may impact water quality by storing high salinity road run‐off during winter overbank events and discharging that water year‐round, thereby attenuating seasonal fluctuations in chloride. Contrary to prior findings, we observed that floodplain connection and riparian vegetation may alter nitrate sources and sinks such that nitrate concentrations increase longitudinally in connected urban streams. Copyright © 2014 John Wiley & Sons, Ltd.