Heat Budget in the Hyporheic Zone of a Large, Gravel-Bed River

大型砾石床河潜流区的热量收支

• 批准号: 0538075
• 负责人: Stephen Lancaster
• 金额: --
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-15 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0538075&HistoricalAwards=false
• 关键词: Heat; Budget; Hyporheic; Zone; Large

This project is a quantitative physics-based study of the heat budget in the hyporheic zone of a large river. It is relevant to current research in the interactions between stream temperature and hyporheic water flux. Understanding heat transfer in hyporheic zones has important implications for water quality and its regulation in the western US, and may be a new tool for researchers, regulators, and water treatment professionals. Preliminary results indicate that warm river water undergoes hyporheic cooling during its transit beneath gravel bars. River-restoration and pollution-credit-trading schemes are being designed around hyporheic cooling strategies, and this makes a full understanding of this phenomenon an imperative. Initial hypotheses include: (1) warm, daytime water is not actually cooled in the hyporheic zone but does push out cool, nighttime water during the day, (2) warm, daytime water is significantly cooled by a) heat flow by conduction to and mixing with deeper groundwater with longer flow paths, b) heat flow by latent and sensible heat fluxes to the vadose zone, and/or c) temporary heat storage in gravels and dead zones in the hyporheic zone. Preliminary tests of these hypotheses will be accomplished through field instrumentation and modeling of water and heat fluxes beneath a gravel bar on a large, gravel-bed river, the Willamette River, Oregon. The research site represents a recently deposited gravel bar of the type found to provide significant apparent cooling. Field data from, site surveying and mapping, shallow wells, seismic profiles, and tracer tests, will characterize and facilitate modeling of the substrate and associated fluxes. This characterization and modeling will constrain the scope and methods for a follow-up study of (1) the adequacy of the platform layout of wells to measure laterally advective heat fluxes, (2) the need for additional wells to measure deeper heat fluxes and storage, (3) the need for three-dimensional seismic data acquisition and/or full tomographic analysis and waveform modeling, to determine boundary conditions.

该项目是对一条大河流潜流带热收支的基于物理的定量研究。 它与当前河流温度和潜流水通量之间相互作用的研究相关。 了解潜流区的传热对于美国西部的水质及其监管具有重要意义，并且可能成为研究人员、监管人员和水处理专业人员的新工具。 初步结果表明，温暖的河水在砾石坝下传输期间经历了潜流冷却。 河流恢复和污染信用交易计划正在围绕潜流冷却策略进行设计，这使得充分了解这种现象势在必行。 最初的假设包括：(1) 温暖的白天水在潜流带中实际上并未被冷却，而是在白天排出凉爽的夜间水，(2) 温暖的白天水通过以下方式显着冷却：a) 通过传导到具有较长流动路径的较深层地下水并与之混合的热流；b) 通过潜热和显热通量流向包气带的热流；和/或 c) 在砾石和死区中临时蓄热。 潜流区。 这些假设的初步测试将通过现场仪器以及对俄勒冈州威拉米特河上砾石坝下的水和热通量进行建模来完成。 该研究地点代表了最近沉积的砾石坝类型，被发现可以提供显着的表观冷却。来自现场勘测和测绘、浅井、地震剖面和示踪剂测试的现场数据将表征并促进基质和相关通量的建模。 这种表征和建模将限制后续研究的范围和方法：(1) 测量横向平流热通量的井平台布局的充分性，(2) 需要额外的井来测量更深的热通量和存储，(3) 需要三维地震数据采集和/或完整的断层扫描分析和波形建模，以确定边界条件。