Landscape-Scale Determinants of the Hydrological and Hydrochemical Responses of Mountainous Catchments

山区流域水文和水化学响应的景观尺度决定因素

• 批准号: 9304794
• 负责人: George Hornberger
• 金额: $ 33.35万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-15 至 1997-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9304794&HistoricalAwards=false
• 关键词: Landscape; Scale; Determinants; Hydrological; Hydrochemical

A quantitative understanding of the hydrochemical response of upland catchments is a fundamental goal of hydrologists and environmental chemists. Such knowledge is needed to ascertain the potential and realized effects, for example, of atmospheric deposition of acids and agricultural chemicals on the catchment (terrestrial and aquatic) ecosystems, of changes of climate on water quality, and of the role of hydrology in the transport of heavy metals and other trace contaminants. In particular, an improved understanding of the factors controlling the variation of dissolved organic carbon (DOC) in headwater streams is of scientific concern for at least two reasons. First, the overall carbon budget of lotic systems is of primary interest to aquatic ecologists seeking a fundamental scientific understanding of these systems. Second, DOC interacts strongly with other dissolved substances (heavy metals in particular) and therefore plays an important role in the transport of contaminants in streams. Heterogeneities in the amount of precipitation delivered to the surface of a catchment, in soil properties and vegetation coverage, and in incident solar radiation can pay an important role in the hydrological response of mountainous catchments. These heterogeneities may be particularly important in influencing how chemicals (e.g., DOC) are delivered from the terrestrial catchment to the stream. Complete characterization of heterogeneities over a catchment is essentially impossible, but is likely to be unnecessary for descriptions of hydrochemical dynamics at the scale of a whole catchment. A possibly fruitful hypothesis is that the heterogeneities that dominate the catchment response are relatively large scale and hence can be identified from readily available data--topography, aerial photography, and satellite imagery -- in conjunction with a modest data-collection program in the field. The proposed work will explore this idea. The effects of spatial patterns in topography, vegetation cover, snow accumulation and melt, and soil transmissivity on the hydrochemical response of the Snake River in Summit County, Colorado will be determined. Spatial data will be analyzed using techniques embodied within geographic information systems (GIS) and synthesized in the context of a hydrological model (TOPMODEL) that will be modified to take into account the identified landscape-scale heterogeneities. Field data on precipitation, flow, hydraulic conductivity, and dissolved constituents (sulfate and DOC, in particular) will be used to evaluate the working hypothesis of the links between large-scale heterogeneity, hydrology, and hydrochemical response.

定量了解高地流域的水化学反应是水文学家和环境化学家的基本目标。 需要这些知识来确定潜在的和实际的影响，例如，酸和农业化学品的大气沉降对流域（陆地和水生）生态系统的影响，气候变化对水质的影响，以及水文学在重金属和其他微量污染物迁移中的作用。 特别是，出于至少两个原因，更好地了解控制源头水流中溶解有机碳（DOC）变化的因素受到科学关注。 首先，水生系统的总体碳预算是寻求对这些系统进行基本科学理解的水生生态学家的主要兴趣。 其次，DOC 与其他溶解物质（特别是重金属）发生强烈相互作用，因此在河流中污染物的输送中发挥着重要作用。 流域表面降水量、土壤性质和植被覆盖度以及入射太阳辐射的异质性在山区流域的水文响应中发挥着重要作用。 这些异质性对于影响化学品（例如 DOC）如何从陆地流域输送到河流可能特别重要。 完整表征流域的异质性本质上是不可能的，但对于描述整个流域规模的水化学动力学可能是不必要的。一个可能富有成果的假设是，主导流域响应的异质性规模相对较大，因此可以从现成的数据（地形、航空摄影和卫星图像）结合现场适度的数据收集计划来识别。 拟议的工作将探讨这个想法。 将确定地形、植被覆盖、积雪和融化以及土壤渗透率等空间格局对科罗拉多州萨米特县斯内克河水化学响应的影响。 空间数据将使用地理信息系统（GIS）中包含的技术进行分析，并在水文模型（TOPMODEL）的背景下进行合成，该模型将被修改以考虑到已识别的景观尺度异质性。 有关降水、流量、导水率和溶解成分（特别是硫酸盐和 DOC）的现场数据将用于评估大规模异质性、水文和水化学响应之间联系的工作假设。