Transient storage in Huey Creek, January 1992 - Field and Modeling data

Abstract copied from Runkel, R.L., McKnight, D.M. and Andrews, E.D., 1998, Analysis of transient storage subject to unsteady flow: Diel flow variation in an Antarctic stream: Journal of North American Benthological Society, v. 17, no. 2, p. 143-154. Transport of dissolved material in streams and small rivers may be characterized using tracer-dilution methods and solute transport models. Recent studies have quantified stream/substream interactions using models of transient storage. These studies are based on tracer-dilution data obtained during periods of steady flow. We present a modeling framework for the analysis of transient storage in stream systems with unsteady flows. The framework couples a kinematic wave routing model with a solute transport model that includes transient storage. The routing model provides time-varying flows and cross-sectional areas that are used as input to the solute transport model. The modeling framework was used to quantify stream/substream interaction in Huey Creek, an Antarctic stream fed exclusively by glacial meltwater. Analysis of tracer-dilution data indicates that there was substantial interaction between the flowing surface water and the hyporheic (substream) zone. The ratio of storage zone area to stream cross-sectional area (As/A) was bigger than 1 in all stream reaches, indicating that the substream area contributing to hyporheic exchange was large relative to stream cross-sectional area. The rate of exchange, as governed by the transient storage exchange coefficient (α), was rapid because of a high stream gradient and porous alluvial materials. Estimates of α generally exceed those determined for other small streams. The high degree of hyporheic exchange supports the hypothesis that weathering reactions within the hyporheos account for observed increases in solute concentration with stream length, as noted in other studies of Antarctic streams.本摘要转载自Runkel RL、McKnight DM及Andrews ED于1998年发表于《北美底栖生物学会期刊》（*Journal of North American Benthological Society*）第17卷第2期，页码143-154的学术论文《非恒定流条件下的瞬态存储分析：南极溪流的日流量变化》。 溪流与小型河流中的溶解物质输运过程，可通过示踪稀释法（tracer-dilution method）与溶质输运模型（solute transport model）进行表征。既往研究已通过瞬态存储（transient storage）模型量化了溪流与亚溪流间的交互作用，此类研究均基于恒定流条件下获取的示踪稀释数据。本文提出一套适用于非恒定流溪流系统的瞬态存储分析建模框架：该框架将运动波汇流模型（kinematic wave routing model）与包含瞬态存储模块的溶质输运模型进行耦合，汇流模型可输出随时间变化的流量与断面面积，作为溶质输运模型的输入参数。 本建模框架被用于量化休伊溪（Huey Creek）的溪流-亚溪流交互作用，该南极溪流仅由冰川融水补给。对示踪稀释数据的分析结果表明，流动地表水与底流带（hyporheic zone，即亚溪流带）之间存在显著交互作用。存储带面积与溪流断面面积之比（As/A）在所有溪流河段中均大于1，表明参与潜流交换的亚溪流面积相较于溪流断面面积占比可观。由瞬态存储交换系数（transient storage exchange coefficient，α）控制的交换速率较快，这源于较高的溪流坡度与多孔冲积河床物质。α的估算值普遍高于其他小型溪流的测定结果。高强度的潜流交换验证了如下假说：正如其他南极溪流研究中所观察到的现象，潜流带内的风化反应是导致溶质浓度随溪流长度增加而升高的原因。