Influence of hyporheic flow and geomorphology on temperature of a large, gravel-bed river, Clackamas River, Oregon, USA
Influence of hyporheic flow and geomorphology on temperature of a large, gravel-bed river, Clackamas River, Oregon, USA
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DOI：
10.1002/hyp.6984
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发表时间：
2008-03-30
影响因子：
3.2
通讯作者：
Wampler, Peter J.
中科院分区：
文献类型：
--
作者：
Burkholder, Barbara K.;Grant, Gordon E.;Wampler, Peter J.
潜流带影响河流的热状况，通过在一定时间尺度内储存和释放热量来缓冲温度。我们研究了克拉克马斯河下游 24 公里河段沿线的潜流交换与温度之间的关系，克拉克马斯河是俄勒冈州西北部的一条大型砾石河床河流（中位流量 = 75.7 m(3)/s；2006 年 8 月最小月平均流量 = 22-7 m(3)/s）。通过一个简单的混合模型，我们估计了在炎热的夏季有多少潜流交换使河流冷却。地下交换主要是通过温度异常来识别的，温度异常是指与主水道至少存在 1 摄氏度温差的水斑。 2006 年夏季，通过现场调查和热红外辐射测量 (TIR)，发现了 40 个次流温度异常。异常的位置与特定的地貌特征相关，主要是作为次流优先通道的坝河道和坝头。三个克拉克马斯砾石坝的详细现场特征和地下水模型表明，潜流水的停留时间可能从几小时到几周甚至几个月不等。这很大程度上是由水力传导率决定的，而水力传导率又受到砾石坝最近形成或改造的影响。将模型流量和水文参数从这些条形图升级到 Clackamas 网络上的其他异常表明，异常引起的潜流流量只占一小部分（
The hyporheic zone influences the thermal regime of rivers, buffering temperature by storing and releasing heat over a range of timescales. We examined the relationship between hyporheic exchange and temperature along a 24-km reach of the lower Clackamas River, a large gravel-bed river in northwestern Oregon (median discharge = 75.7 m(3)/s; minimum mean monthly discharge = 22-7 m(3)/s in August 2006). With a simple mixing model, we estimated how much hyporheic exchange cools the river during hot Summer months. Hyporheic exchange was primarily identified by temperature anomalies, which are patches of water that demonstrate at least a 1 degrees C temperature difference from the main channel. Forty hyporheic temperature anomalies were identified through field investigations and thermal-infrared-raiometry (TIR) in summer 2006. The location of anomalies was associated with specific geomorphic features, primarily bar channels and bar heads that act as preferential pathways for hyporheic flow. Detailed field characterization and groundwater modelling on three Clackamas gravel bars indicate residence times of hyporheic water can vary from hours to weeks and months. This was largely determined by hydraulic conductivity, which is affected by how recently the gravel bar formed or was reworked. Upscaling of modelled discharges and hydrologic parameters from these bars to other anomalies on the Clackamas network shows that hyporheic discharge from anomalies comprises a small fraction (