Hydroecological Organization and Dynamics in Urbanizing Watersheds

水通过景观运动的机制和途径与控制陆水营养负荷的人类/生态系统过程之间的联系尚未得到清楚的认识。这一领域的研究已被引用为地理、水文和生态系统科学的优先需求。本项目具体评估和量化了流域水文和生态系统形态和过程的空间组织和连通性对城市化流域氮循环和输出动态的作用。这项工作将包括自然和人为改变的景观，重点是我们目前正在监测的地区，作为巴尔的摩生态系统研究的一部分，这是一个由美国国家科学基金会资助的长期生态研究站点。该项目包括对土壤湿度、水流流量和养分浓度模式进行实地采样。将开发一个综合空间水文生态数据和模拟系统（即地理信息系统GIS）和一套指数，以预测和解释生态系统和流域氮输出对地表覆盖和水文流道变化的敏感性。该项目将发展重要的数据、理论和技术，以评估人类在景观水平（例如小集水区或社区）对综合水文和生态系统过程的影响。GIS/建模系统代表和模拟了生态系统、水、碳和营养物质的储存和沿着山坡尺度（山脊到溪流）的排水路径循环的模式。这些排水序列反过来影响城市化流域典型细分尺度上的流域养分输出效率。该项目通过提供更高的空间和时间分辨率信息，增强和补充了巴尔的摩生态系统研究的长期监测组成部分，这些信息集中在适合设计和修复工作的小流域内的水文和生态系统过程。这项研究将使人们更好地了解自然和设计景观格局对流域累积影响的作用，提高评价流域发展和恢复备选方案的能力，以及快速筛选现有发展模式以获取养分出口潜力的工具。

The linkages between the mechanisms and pathways of water movement through landscape, and the human/ecosystem processes controlling terrestrial-aquatic nutrient loading, have not been clearly understood. This area of research has been cited as a priority need in geographic, hydrologic, and ecosystem sciences. This project specifically assesses and quantifies the role played by the spatial organization and connectivity of watershed hydrologic and ecosystem form and process on the dynamics of nitrogen cycling and export in urbanizing watersheds. The work will include both natural and human modified landscapes, focussing on areas we are currently monitoring as part of the Baltimore Ecosystem Study, an NSF funded Long Term Ecological Research site. The project includes field sampling of soil moisture, stream discharge, and nutrient concentration patterns. An integrated spatial hydroecological data and simulation system (i.e., a geographic information system GIS) and a set of indices will be developed to predict and explain the sensitivity of ecosystem and catchment export of nitrogen to alterations in surface cover and hydrologic flowpaths.The project will develop important data, theory, and techniques assessing the impacts of human modification of integrated hydrologic and ecosystem processes at the landscape level (e.g., small catchments or neighborhoods). The GIS/modeling system represents and simulates the pattern of ecosystem, water, carbon, and nutrient storage and cycling along drainage flowpaths at the hillslope scale (ridge to stream). These drainage sequences in turn influence catchment export efficiency of nutrients at the scale of typical subdivisions in urbanizing watersheds. This project augments and complements the long term monitoring components of the Baltimore Ecosystem Study by providing higher spatial and temporal resolution information focussing on hydrologic and ecosystem processes within small watersheds that are amenable to design and restoration efforts. The research will generate a better understanding of the role of natural and designed landscape patterns on cumulative watershed impacts, a capability to evaluate alternative watershed development and restoration scenarios, and tools to rapidly screen existing development patterns for nutrient export potential.