The urban watershed continuum: evolving spatial and temporal dimensions
The urban watershed continuum: evolving spatial and temporal dimensions
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DOI：
10.1007/s11252-012-0226-7
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发表时间：
2012-06-01
期刊：
影响因子：
2.9
通讯作者：
Belt, Kenneth T.
中科院分区：
文献类型：
--
作者：
Kaushal, Sujay S.;Belt, Kenneth T.
城市生态系统在不断演变，随着积极的管理或退化，预计它们将在空间和时间上发生变化。城市流域连续体框架承认工程和自然水文流径的连续体，以很少考虑的方式扩展水文网络。它认识到水文连通性的性质会影响下游碳、污染物、能量和营养物质在4个空间和时间维度上的通量和转化。具体而言，它提出：（1）一级流在很大程度上被城市基础设施所取代（如雨水渠、沟渠、排水沟、管道），（2）在工程源头中，有机碳和养分保留存在广泛的纵向和横向变化（3）在物质和能量输出中存在纵向下游脉冲，这些脉冲被相互作用的陆地-（4）渗漏管道和地下水之间存在垂直相互作用，影响河流溶质运移;（5）基于水文停留时间，城市流域连续体是物质和能量的Transformer和运输者;（6）随着土地利用和城市基础设施的变化，生态系统功能和地球化学循环也会发生演变。我们提供的例子从巴尔的摩生态系统研究长期生态（LTER）网站沿着4时空维度。长期监测表明，与未开发的源头相比，工程源头增加了下游硝酸盐，磷酸盐，硫酸盐，碳和金属的补贴。有增加的碳和氮的纵向转换从郊区的源头沃茨到更城市化的接收沃茨。水文连通性沿着地下水和漏水管道之间的垂直尺寸从巴尔的摩的老化基础设施提高流溶质浓度。随着时间的推移，有越来越多的源头流埋葬，不断发展的雨水管理，和长期盐碱化的巴尔的摩的饮用水供应。总体而言，城市流域连续体框架提出了可检验的假设，即物质和能量的运输/转化如何在空间和时间上沿工程和自然水文流径的连续体沿着变化。考虑到人们对从卫生城市向可持续城市过渡的兴趣，有必要认识到基础设施与生态系统功能之间的关系在沿着城市流域连续体不断演变。
Urban ecosystems are constantly evolving, and they are expected to change in both space and time with active management or degradation. An urban watershed continuum framework recognizes a continuum of engineered and natural hydrologic flowpaths that expands hydrologic networks in ways that are seldom considered. It recognizes that the nature of hydrologic connectivity influences downstream fluxes and transformations of carbon, contaminants, energy, and nutrients across 4 space and time dimensions. Specifically, it proposes that (1) first order streams are largely replaced by urban infrastructure (e.g. storm drains, ditches, gutters, pipes) longitudinally and laterally within watersheds, (2) there is extensive longitudinal and lateral modification of organic carbon and nutrient retention in engineered headwaters (3) there are longitudinal downstream pulses in material and energy exports that are amplified by interactive land-use and hydrologic variability, (4) there are vertical interactions between leaky pipes and ground water that influence stream solute transport, (5) the urban watershed continuum is a transformer and transporter of materials and energy based on hydrologic residence times, and (6) temporally, there is an evolution of biogeochemical cycles and ecosystem functions as land use and urban infrastructure change over time. We provide examples from the Baltimore Ecosystem Study Long-Term Ecological (LTER) site along 4 spatiotemporal dimensions. Long-term monitoring indicates that engineered headwaters increase downstream subsidies of nitrate, phosphate, sulfate, carbon, and metals compared with undeveloped headwaters. There are increased longitudinal transformations of carbon and nitrogen from suburban headwaters to more urbanized receiving waters. Hydrologic connectivity along the vertical dimension between ground water and leaky pipes from Baltimore's aging infrastructure elevates stream solute concentrations. Across time, there has been increased headwater stream burial, evolving stormwater management, and long-term salinization of Baltimore's drinking water supply. Overall, an urban watershed continuum framework proposes testable hypotheses of how transport/transformation of materials and energy vary along a continuum of engineered and natural hydrologic flowpaths in space and time. Given interest in transitioning from sanitary to sustainable cities, it is necessary to recognize the evolving relationship between infrastructure and ecosystem function along the urban watershed continuum.