COMPACT: The role of soil management in mitigating catchment flood risk

紧凑：土壤管理在减轻流域洪水风险中的作用

• 批准号: NE/P014399/1
• 负责人: Ian Pattison
• 金额: $ 26.39万
• 依托单位: Loughborough University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FP014399%2F1
• 关键词: COMPACT; role; soil; management; mitigating

Flood risk is an increasing challenge in the UK, with 2.4 million properties being susceptible to fluvial flooding. This type of flooding is caused by the quantity of runoff being discharged by a river exceeding the capacity of the river channel. This results in water being transferred to the floodplain, which can have severe economic and social impacts. The quantity and speed of runoff from the landscape into rivers is a major factor in generating flooding. The way in which the landscape is managed therefore can have a significant impact on this process. The intensification of agriculture, through increasing the number of animals in pasture, and the use of larger, heavier machinery for arable farming, over the past 50 years or so is hypothesised to have had an impact on the severity and frequency of flooding. These land management practices cause soil compaction, which reduces the rate of rainfall infiltration and the volume of water that can be stored within the sub-surface. This results in more rainfall being partitioned into the faster surface runoff pathway into rivers and potentially causing flooding downstream.However, the level of soil compaction is highly heterogeneous over space and time. This is because different animals i.e. cattle, sheep and horses, exert different loads on the soil and are kept at different densities. Furthermore, farm animals are known to exhibit behaviour whereby certain parts of the field are moved over more frequently than others. The same is the case in arable farming practices, whereby ploughing forms tramlines or wheelings, which are more compacted. Different forms of management practice ranging from zero-tillage to conventional cultivation exert different pressures on the soil at different times of year. However, very little is known about this variability of soil compaction levels at the sub-field level and land under different management practices.This research aims to quantify this sub-field variation in compaction severity and depths through using novel Ground Penetrating Radar (GPR) technology, and assess the impact on the physical soil properties, how water interacts with the soil and ultimately how important this effect is on catchment scale flood risk. This will be achieved through using a multi-methods approach combining field experiments, laboratory tests on soil samples and numerical hydrological modelling. First areas of high and low compaction will be identified using GPR and validated using traditional field based approaches. These will be related to loadings through GPS spatial data on where animals and machinery have moved over. A wide range of field and laboratory tests will then be carried out to quantify properties such as bulk density, porosity, saturated hydraulic conductivity, and particle size. Furthermore, X-Ray CT scanning will reveal the fine scale impacts of compaction on soil structure. This data will form the input to a physically based, reduced complexity, spatially distributed hydrological model, CRUM3. Feasible "what if?" scenarios will be co-produced with the project partners, including the Environment Agency, Trent Rivers Trust, Sustainable Land Trust, Natural England, and National Farmers Union through the Soar Catchment Partnership. This will upscale local changes in land management and soil characteristics to catchment scale flooding.This research will be undertaken with a group of catchment managers, land owners and local residents. This will both benefit the research scope and impacts of the findings. Recommendations and dissemination for industry, regulators, governmental bodies, charities and local land owners and residents will inform evidence based policy on Natural Flood Management. This will be achieved through steering group meetings, a British Hydrological Society national meeting, Project Away day, end of project riverside picnic, and the use of social media. Dissemination will also occur through more traditional academic routes.

洪水风险在英国是一个日益严峻的挑战，有 240 万处房产容易受到河流洪水的影响。这种类型的洪水是由于河流排放的径流超过河道容量而引起的。这导致水被转移到洪泛区，从而可能产生严重的经济和社会影响。从景观流入河流的径流的数量和速度是产生洪水的主要因素。因此，景观管理方式会对这一过程产生重大影响。据推测，在过去 50 年左右的时间里，通过增加牧场动物数量以及使用更大、更重的机械进行耕作，农业集约化对洪水的严重程度和频率产生了影响。这些土地管理做法会导致土壤压实，从而降低降雨入渗率和地下可储存的水量。这导致更多的降雨被分配到更快的地表径流进入河流，并可能导致下游洪水。然而，土壤压实程度在空间和时间上是高度异质的。这是因为不同的动物，即牛、羊和马，对土壤施加不同的负荷，并且饲养密度不同。此外，众所周知，农场动物表现出的行为是，田地的某些部分比其他部分更频繁地移动。耕作方式也是如此，犁耕形成更紧凑的轨道或轮机。从零耕到常规耕作等不同形式的管理实践在一年中的不同时间对土壤施加不同的压力。然而，人们对不同管理实践下子田水平和土地上土壤压实程度的变化知之甚少。本研究旨在通过使用新型探地雷达（GPR）技术来量化压实严重程度和深度的子田变化，并评估其对土壤物理性质的影响、水与土壤的相互作用以及最终这种影响对流域规模洪水风险的重要性。这将通过结合现场实验、土壤样本实验室测试和数值水文模型的多种方法来实现。第一批高压实和低压实区域将使用探地雷达进行识别，并使用传统的现场方法进行验证。这些将通过 GPS 空间数据与动物和机械移动位置的负载相关。然后将进行广泛的现场和实验室测试，以量化堆积密度、孔隙率、饱和导水率和颗粒尺寸等特性。此外，X 射线 CT 扫描将揭示压实对土壤结构的精细影响。该数据将形成基于物理的、复杂性降低的空间分布水文模型 CRUM3 的输入。可行的“如果呢？”这些情景将通过 Soar Catchment Partnership 与项目合作伙伴共同制作，包括环境局、特伦特河信托基金、可持续土地信托基金、自然英格兰和全国农民联盟。这将把当地土地管理和土壤特性的变化升级为流域规模的洪水。这项研究将与一组流域管理者、土地所有者和当地居民一起进行。这将有利于研究范围和研究结果的影响。向行业、监管机构、政府机构、慈善机构以及当地土地所有者和居民提出的建议和传播将为基于证据的自然洪水管理政策提供信息。这将通过指导小组会议、英国水文学会全国会议、项目离开日、项目结束河边野餐以及社交媒体的使用来实现。传播也将通过更传统的学术途径进行。