Interactions Between Streams and Groundwater Along the River Continuum: Scaling up to a Stream Network

9909564Wondzell我们的研究的目的是评估控制潜流交换流的因素的相对重要性，并提供所需的数据，以完善概念模型，描述的范围内的潜流区及其对河流生态系统的影响跨尺度范围从单个流达到整个流网络。 我们将使用广泛的流调查，以表征在山区溪流网络的通道和谷底形态特征的变化范围，并使用MODFLOW作为一种工具，探索hyporheic交换流的形态特征的敏感性。 根据现有研究中心校准的MODFLOW模拟将作为这些敏感性分析的起点。 一系列的模拟将进行分析，以确定交换流量的敏感性，存在和不存在的二级渠道，不同的渠道弯曲度，沉积物深度，饱和导水率（k），和空间异质性的k，存在或不存在的日志堵塞，以及不同的组合的纵向通道梯度和池步骤结构。 模型预测将使用保守的示踪剂时间的溪流水到威尔斯在一个子集的流达到我们的调查。 我们将研究这些控制因素的相对重要性，在不同大小的流和不同程度的渠道约束。 此外，我们将比较流达到管理森林与荒野地区，以确定土地管理措施的影响，控制潜流交换流量的因素。

9909564Wondzell The objective of our study is to assess the relative importance of the factors controlling hyporheic exchange flow and provide the data needed to refine conceptual models that describe the extent of the hyporheic zone and its influence on stream ecosystems across scales ranging from individual stream reaches to entire stream networks. We will use extensive stream surveys to characterize the range of variability in channel and valley floor morphologic features in mountain stream networks, and use MODFLOW as a tool to explore the sensitivity of hyporheic exchange flows to morphologic features. MODFLOW simulations calibrated to existing study sites will serve as the starting point for these sensitivity analyses. A series of simulations will be analyzed to determine the sensitivity of exchange flows to the presence and absence of secondary channels, differing channel sinuosities, sediment depth, saturated hydraulic conductivity (k), and spatial heterogeneity of k, presence or absence of log jams, and different combinations of longitudinal channel gradient and pool-step structure. Model predictions will be verified using conservative tracer time of stream water to wells in a subset of the stream reaches we survey. We will examine the relative importance of these controlling factors in streams of different sizes and with differing degrees of channel constraint. Further, we will compare stream reaches in managed forests with those in wilderness areas to determine the effect of land management practices on the factors controlling hyporheic exchange flows.