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Modelling water quality response to climate and large-scale land-use change using the world's longest water quality time series (1868 to date)

使用世界上最长的水质时间序列（1868 年至今）模拟水质对气候和大规模土地利用变化的响应

基本信息

批准号：
NE/H000704/1
负责人：
Nicholas Howden
金额：
$ 11.92万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FH000704%2F1
关键词：
Modelling water quality response climate

项目摘要

Estimates suggest human activity has doubled the rate at which biologically available nitrogen enters the environment when compared to pre-industrial levels. This has led to nutrient enrichment of surface and groundwaters causing low dissolved oxygen levels, loss of habitat and freshwater and riparian biodiversity, lowered drinking water quality and, in some places, increased occurrence of algal blooms. Globally, Western Europe is regarded as a 'hot spot' of riverine nitrogen flux and some of the highest nitrate concentrations are found in UK rivers, particularly the River Thames. This is due to the population density, the extent of high-input agriculture within the country, and the small, relatively unimpeded nature of UK rivers. The potential for human impact on riverine nutrient and carbon fluxes by large-scale land-use and management change has been demonstrated, and suggested to be of potentially greater water quality significance than projected climate change impacts. Recent UK work has shown that groundwater-dominated river catchments exhibit a long-term (i.e. >30 year) nitrate response linked to agricultural intensification in the 1950s, 60s and 70s. This is particularly significant because groundwater flows are slow so transfers from the land to rivers via groundwater may take up to tens or even hundreds of years. In the past uncertainty about what is presently contained in the groundwater led to talk of a possible nutrient 'time bomb', due to affect rivers at some point in the future. It has been shown that groundwater-dominated river responses to changes in the catchment require many years of monitoring data (possibly going back further than the 1940s) in order to fully understand the rate and magnitude of land to river transfers. This has provided a crucial new perspective on the importance of long-term catchment function, but alarmingly, in England, there are few data from before the establishment of the water authorities in 1974 to support interpretation of such processes. In response to this researchers have used archived paper records to construct the world's longest water quality time series comprising monthly average nitrate concentrations for the River Thames upstream of London for the period 1868 to the present. This allows a unique insight into water quality changes affected by direct human influences over the period, the timing and character of catchment responses to changing land use and land management policy, and comparison of the magnitude of these influences with potential impacts of climate change over a sufficiently long period. The proposed research will use this Thames record to develop new methods and models, coupled with traditional statistical methods, to characterise and predict changes in river nutrient concentrations in both the short- and long-term. This will allow the rates at which groundwater nutrient transport can make land to river transfers and will help to identify whether projected climate change impacts will be as big a threat to water quality as large-scale changes in land use. This will enable freshwater and catchment scientists to gain a better understanding of long-term processes and will help policymakers to prioritise actions and make decisions. It will also show the ways in which monitoring programmes need to be managed to provide appropriate data, and the ways in which those data need to be interpreted if we are to manage our natural resources effectively and sustainably in the long-term.

估计表明，与工业化前水平相比，人类活动使生物可用氮进入环境的速度增加了一倍。这导致地表水和地下水的营养物质富集，导致溶解氧水平降低，栖息地和淡水及河岸生物多样性丧失，饮用水质量下降，在一些地方，藻华现象增加。在全球范围内，西欧被认为是河流氮通量的“热点”，在英国的河流中发现了一些最高的硝酸盐浓度，尤其是泰晤士河。这是由于人口密度，国内高投入农业的程度，以及英国河流较小，相对畅通的性质。人类通过大规模土地利用和管理变化对河流养分和碳通量的潜在影响已得到证实，并表明其对水质的潜在影响可能比预估的气候变化影响更大。英国最近的研究表明，地下水占主导地位的河流集水区与20世纪50年代、60年代和70年代的农业集约化有关，表现出长期（即50至30年）的硝酸盐响应。这一点尤其重要，因为地下水流动缓慢，因此通过地下水从陆地转移到河流可能需要数十年甚至数百年的时间。在过去，由于不确定目前地下水中含有什么，人们谈到可能存在一颗营养“定时炸弹”，因为它在未来的某个时候会影响河流。研究表明，地下水主导的河流对集水区变化的响应需要多年的监测数据（可能要追溯到20世纪40年代以前），以便充分了解土地向河流转移的速度和规模。这为长期集水区功能的重要性提供了一个至关重要的新视角，但令人担忧的是，在英国，1974年水务局成立之前的数据很少，不足以支持对这一过程的解释。为了回应这一问题，研究人员利用存档的纸质记录构建了世界上最长的水质时间序列，包括1868年至今伦敦上游泰晤士河的每月平均硝酸盐浓度。这使我们能够独特地了解这一时期内受人类直接影响影响的水质变化，流域对土地利用和土地管理政策变化的反应的时间和特征，以及在足够长的时期内将这些影响的幅度与气候变化的潜在影响进行比较。拟议中的研究将利用泰晤士河的记录来开发新的方法和模型，结合传统的统计方法，来描述和预测河流营养物质浓度的短期和长期变化。这将允许地下水养分运输使土地向河流转移的速率，并将有助于确定预测的气候变化影响对水质的威胁是否与土地利用的大规模变化一样大。这将使淡水和流域科学家能够更好地了解长期过程，并将帮助决策者确定行动的优先次序和做出决策。它还将说明如何管理监测方案以提供适当的数据，以及如果我们要长期有效和可持续地管理我们的自然资源，需要如何解释这些数据。