Large woody debris -A river restoration panacea for streambed nitrate attenuation?

大型木质碎片 - 河床硝酸盐衰减的河流恢复灵丹妙药？

• 批准号: NE/L003872/1
• 负责人: Stefan Krause
• 金额: $ 63.35万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FL003872%2F1
• 关键词: Large; woody; debris; river; restoration

For centuries, large woody debris has been removed from UK and European rivers to reduce potential flood risks caused by these obstacles and blockage. However, the removal of large woody debris has been shown to severely impact on ecosystem services provided by rivers, including habitat functioning and the potential to reduce nutrient and sediment loading by acting as both a physical and biochemical barriers. This caused detrimental impacts on in-stream and floodplain biota as well as society in the provision of clean drinking water.Recent EU and UK environmental policies (notably the European Water Framework Directive) are promoting a significant shift in management practices, strongly emphasizing the reintroduction of in-stream wood to improve the resilience of lowland river ecosystems to environmental change by increasing their capacity to attenuate excess nitrate pollution. As obstacle in the river, woody debris is expected to increase the down-welling of surface water into the streambed and enhance its contact time in the very reactive streambed zone, resulting in increased chemical turnover and nitrate attenuation. However, the impacts of large woody debris on the main drivers of biogeochemical processes in the streambed, the exchange fluxes between groundwater and surface water as well as the residence time of water in the streambed are poorly understood. To improve design of large woody debris structures to efficiently remove nitrate from the streambed, river basin management and restoration programmes require scientific evidence for the effectiveness of different large woody debris designs for water quality improvement.This project will therefore provide the scientific evidence required for assessing the efficiency of different permanent and mobile designs of large woody debris for enhancing the uptake of nitrogen in lowland rivers. Our research focuses specifically on lowland streams as these represent the majority of UK rivers under threat of critically high nitrate concentrations. The findings of this project will directly inform river restoration practice and decide whether, to what degree and with what design, large woody debris will be deployed in UK lowland streams to reduce critically high nitrate loads.We will combine novel monitoring techniques and environmental tracer technologies with innovative numerical modelling approaches to identify the occurrence of streambed hotspots of increased biogeochemical turnover that are facilitated by large woody debris. We will quantify to what degree excess nitrate concentrations can be reduced in this reactive hotspots and what different designs of large woody debris structures best facilitate this ecosystem service. We will improve sophisticated numerical models to quantify how effective permanent and mobile large woody debris may attenuate excess nitrate from lowland rivers. By developing and simulating a set of scenarios, assuming wider ranges of environmental conditions then observed experimentally, we will predict how efficiently different large woody debris structures in lowland rivers can reduce nitrate pollution under changing environmental conditions. Knowledge of how in-stream wood facilitates the occurrence of biogeochemical hotspots will assist river managers in adopting techniques which deliver benefits to both in-stream biota and water quality for human uses. This project, twinned with the proposed policy advice documents we will develop, will provide an ideal opportunity for the formation of science-based restoration activities which are able to deliver quantitative water quality improvements for little to no additional cost.

几个世纪以来，英国和欧洲河流中的大型木质碎片已被清除，以减少这些障碍物和堵塞造成的潜在洪水风险。然而，事实证明，清除大型木质碎片会严重影响河流提供的生态系统服务，包括栖息地功能以及通过充当物理和生化屏障来减少养分和沉积物负荷的潜力。这对河流和洪泛区生物群以及社会提供清洁饮用水造成了不利影响。最近的欧盟和英国环境政策（特别是欧洲水框架指令）正在促进管理实践的重大转变，强烈强调重新引入河内木材的利用，通过提高低地河流生态系统减少过量硝酸盐污染的能力，提高其对环境变化的适应能力。作为河流中的障碍物，木质碎屑预计会增加地表水流入河床的速度，并延长其在反应性非常强的河床区域的接触时间，从而导致化学周转增加和硝酸盐衰减。然而，人们对大型木质碎屑对河床生物地球化学过程的主要驱动因素、地下水与地表水之间的交换通量以及水在河床中的停留时间的影响知之甚少。为了改进大型木质碎屑结构的设计，以有效去除河床中的硝酸盐，流域管理和恢复计划需要科学证据来证明不同大型木质碎屑设计对改善水质的有效性。因此，该项目将为评估提供所需的科学证据。大型木质碎片的不同永久和移动设计对于增强低地河流氮吸收的效率。我们的研究特别关注低地溪流，因为这些溪流代表了英国大多数河流受到极高硝酸盐浓度威胁的情况。该项目的研究结果将直接为河流恢复实践提供信息，并决定是否在英国低地溪流中部署大型木质碎片、在何种程度上以及采用何种设计，以减少极高的硝酸盐负荷。我们将结合新颖的监测技术和环境示踪技术采用创新的数值模拟方法来确定由大型木质碎片促进的生物地球化学周转增加的河床热点的出现。我们将量化这个反应热点中过量的硝酸盐浓度可以减少到什么程度，以及大型木质碎片结构的哪些不同设计最能促进这种生态系统服务。我们将改进复杂的数值模型，以量化永久和移动的大型木质碎片如何有效地减少低地河流中过量的硝酸盐。通过开发和模拟一组情景，假设更广泛的环境条件，然后通过实验观察到，我们将预测低地河流中不同的大型木质碎片结构在不断变化的环境条件下如何有效地减少硝酸盐污染。了解河内木材如何促进生物地球化学热点的出现将有助于河流管理者采用为河内生物群和人类使用的水质带来好处的技术。该项目与我们将制定的拟议政策建议文件相结合，将为形成基于科学的恢复活动提供理想的机会，这些活动能够以很少甚至无需额外成本实现定量的水质改善。

项目成果

Helophyte impacts on the response of hyporheic invertebrate communities to inundation events in intermittent streams

• DOI: 10.1002/eco.1857
• 发表时间: 2017-09-01
• 期刊: ECOHYDROLOGY
• 影响因子: 2.6
• 作者: Baranov, Viktor;Milosevic, Djuradj;Krause, Stefan
• 通讯作者: Krause, Stefan

The method controls the story - Sampling method impacts on the detection of pore-water nitrogen concentrations in streambeds.

该方法控制了故事 - 采样方法对河床孔隙水氮浓度检测的影响。

• DOI: 10.1016/j.scitotenv.2019.136075
• 发表时间: 2020
• 期刊: The Science of the total environment
• 作者: Comer-Warner S

Using multi-tracer inference to move beyond single-catchment ecohydrology

• DOI: 10.1016/j.earscirev.2016.06.014
• 发表时间: 2016-09-01
• 期刊: EARTH-SCIENCE REVIEWS
• 影响因子: 12.1
• 作者: Abbott, Benjamin W.;Baranov, Viktor;Pinay, Gilles
• 通讯作者: Pinay, Gilles

Identification of floodplain and riverbed sediment heterogeneity in a meandering UK lowland stream by ground penetrating radar

利用探地雷达识别英国蜿蜒低地溪流中的漫滩和河床沉积物异质性

• DOI: 10.1016/j.jappgeo.2019.103863
• 发表时间: 2019
• 期刊: Journal of Applied Geophysics
• 影响因子: 2
• 作者: Dara R

Multitracer Field Fluorometry: Accounting for Temperature and Turbidity Variability During Stream Tracer Tests

• DOI: 10.1002/2017wr020815
• 发表时间: 2017-11-01
• 期刊: WATER RESOURCES RESEARCH
• 影响因子: 5.4
• 作者: Blaen, Phillip J.;Brekenfeld, Nicolai;Krause, Stefan
• 通讯作者: Krause, Stefan