Quantifying Urban Groundwater in Environmental Field Observatories: A Missing Link in Understanding How the Built Environment Affects the Hydrologic Cycle

尽管城市景观的足迹及其对水文和生物地球化学循环的影响越来越大，但对城市水收支的全面实地研究很少。城市基础设施(建筑物、道路、涵洞、雨水渠、蓄水池、泄漏的供水和污水管网)对地下水储存、通量和流动路径的时空格局的累积影响尚不清楚。任何环境观测网络都必须包括了解城市景观中的关键过程的努力，而城市环水可以公平地描述为我们对自然和建筑环境综合功能的理解中缺失的一环。该项目的目标是开发城市地下水系统的专业知识和分析工具，为未来的环境观测站规划提供信息，并可与在其他城市环境工作的研究团队共享。我们的工作计划借鉴了马里兰州由巴尔的摩生态系统研究(BES)、美国地质调查局和美国森林服务局与来自多个机构的大学科学家和工程师正在进行的监测工作提供的一组强大的信息资源。巴尔的摩市和巴尔的摩县都与美国环保局签署了同意法令，以缓解卫生下水道网络的故障，这导致更多地部署了降雨、地下水和废水流量传感器，包括用于实时数据收集的无线遥测。拟议的项目将利用这些资源，在监测、建模和数据库开发方面进行战略投资，以制定对城市地区地下水系统进行量化的协议。一个主要关切是利用天气实地调查、遥感、数值模拟、数据挖掘和可视化工具，弥合小规模密集实地研究与较大规模和较长期水文模式之间的差距。以城市水预算为统一主题，我们建议对预算的各个要素进行估算，以量化城市基础设施对地下水的影响。拟议的工作包括：(1)在0.8至171平方公里的四个不同空间尺度上比较一组嵌套流域的水流计的基流行为，这些流域具有不同的防渗覆盖和城市基础设施模式；(2)对井水位进行天气调查，以确定区域地下水位的特征；(3)利用航空热红外图像来确定地下水渗入各种城市发展模式的河流的位置；(4)利用渗流横断面和示踪试验来量化进入选定分流域的排水网络的地下水通量的空间模式；(5)使用用于天气雷达产品偏差校正的记录雨量计，在170平方公里的网格上建立降水质量平衡；(5)使用Penman-Monteith方法计算城市蒸散量，并与涡旋相关站的结果进行比较；(7)在筛选模式下使用数值地下水模型来估计地下水的地表水流深度；(8)对公共机构的饮用水和废水流量记录进行数据挖掘，以估计与径流和地下水通量有关的泄漏率和流动路径；以及(9)评估应用于城市环境的CUAHSI水文信息系统数据建模工具。该项目将为环境观测站的发展提供指导，这些观测站不仅为基础科学提供重要信息，而且为影响人类和生态系统未来健康和福祉的重要资源的管理提供重要信息。该项目还将有助于研究生和本科生的教育。研究生将在夏季实地考察期间作为研究助理参加，由密歇根大学城市环境研究和教育中心协调。我们将重点招聘密歇根大学迈耶霍夫奖学金项目的本科生助理，该项目在培养致力于理工科研究生教育的少数民族人才方面享誉全国。通过巴尔的摩生态系统研究LTER，由BES教育协调员管理的一个广泛的外展教育计划已经在巴尔的摩市中心的学校和巴尔的摩县郊区的学校中实施，其中包括在环境科学课程中包含一个水文科学模块。拟议工作的成果可有助于/加强这一正在进行的课程开发工作。

0610009WeltyDespite the growing footprint of urban landscapes and their impacts onhydrologic and biogeochemical cycles, comprehensive field studies of urban water budgets are few.The cumulative effects of urban infrastructure (buildings, roads, culverts, storm drains, detentionponds, leaking water supply and wastewater pipe networks) on temporal and spatial patterns ofgroundwater stores, fluxes, and flowpaths are poorly understood. Any environmental observatorynetwork must include efforts to understand critical processes in urban landscapes, and urbangroundwater can fairly be characterized as a missing link in our understanding of the integratedfunctioning of the natural and built environment. The goal of this project is to develop expertise andanalytical tools for urban groundwater systems that will inform future environmental observatoryplanning and that can be shared with research teams working in urban environments elsewhere.Our work plan draws on a robust set of information resources in Maryland provided by ongoingmonitoring efforts of the Baltimore Ecosystem Study (BES), USGS, and the U.S. Forest Serviceworking together with university scientists and engineers from multiple institutions. Consent decrees,signed by both Baltimore City and Baltimore County with U.S. EPA to mitigate failures in the sanitarysewer network, are leading to increased deployment of rainfall, groundwater and wastewater flowsensors including wireless telemetry for real-time data collection. The proposed project will leveragethese resources with strategic investments in monitoring, modeling and database development toestablish protocols for quantifying groundwater systems in urban areas.A key concern is to bridge the gap between small-scale intensive field studies and larger-scale andlonger-term hydrologic patterns using synoptic field surveys, remote sensing, numerical modeling,data mining and visualization tools. Using the urban water budget as a unifying theme, we proposeto estimate the various elements of the budget in order to quantify the influence of urbaninfrastructure on groundwater. Proposed efforts include: (1) comparison of base flow behavior fromstream gauges in a nested set of watersheds at four different spatial scales from 0.8 to 171 km2, withdiverse patterns of impervious cover and urban infrastructure; (2) synoptic survey of well waterlevels to characterize the regional water table; (3) use of airborne thermal infrared imagery to identifylocations of groundwater seepage into streams across a range of urban development patterns; (4)use of seepage transects and tracer tests to quantify the spatial pattern of groundwater fluxes to thedrainage network in selected subwatersheds; (5) development of a mass balance for precipitationover a 170 km2 area on a 1x1 km2 grid using recording rain gages for bias correction of weatherradar products; (5) calculation of urban evapotranspiration using the Penman-Monteith methodcompared with results from an eddy correlation station; (7) use of numerical groundwater model in ascreening mode to estimate depth of groundwater contributing surface water flow; (8) data mining ofpublic agency records of potable water and wastewater flows to estimate leakage rates andflowpaths in relation to streamflow and groundwater fluxes; and (9) evaluation of the CUAHSIHydrologic Information Systems data modeling tools for application to urban environments.Broader Impacts. The project will provide guidance for development of environmentalobservatories, which are envisioned as providing critical information not only for basic science but formanagement of vital resources affecting the future health and well-being of both human populationsand ecosystems. The project also will contribute to the education of graduate and undergraduatestudents. Graduate students will participate as research assistants during the summer field season,as coordinated through UMBC's Center for Urban Environmental Research and Education. We willemphasize recruitment of undergraduate student assistants from UMBC's Meyerhoff Scholarsprogram, which has a national reputation for training of talented minority students committed tograduate education in science and engineering. Through the Baltimore Ecosystem Study LTER, anextensive outreach educational program managed by the BES education coordinator is already inplace with inner city Baltimore schools and with suburban Baltimore County schools, which includesa hydrologic science module within the environmental science curriculum. Results from theproposed work can contribute to/enhance this ongoing curriculum development effort.