河流近域土地利用格局与水质相关性分析——以巢湖流域为例

以河流近域土地利用构成与水环境质量间定量关系为研究对象,基于巢湖流域40个水质监测断面和320个河流近域作用区,运用GIS空间分析功能计算不同尺度作用区内土地利用构成,借助相关分析、冗余分析(RDA)等数理统计手段,分析土地利用构成与水质指数间的相关关系;并分析和比较了流域内山区和平原地区土地利用构成与水质之间关系。结果表明,巢湖流域近河道地区土地利用构成对各水质指数有重要影响,且受地形因素影响。其中,建设用地对河流水质恶化具有明显作用;河流沿岸林地布局能显著改善水质,尤其是对氨氮和高锰酸盐指数敏感;耕地面积变化与水质相关性不显著。RDA冗余分析证实了不同尺度下的土地利用类型对水环境影响具有尺度效应。研究成果对巢湖流域水环境管理具有重要的实际指导意义,并为同类研究提供借鉴     

基于遥感和GIS的赤水河水质对流域土地利用的响应研究

利用2009年TM影像和11个断面的水质监测数据,同时在缓冲区和子流域尺度上,分析了赤水河流域内土地利用方式与水质指标（溶解氧、高锰酸盐指数、氨氮）之间的相关关系,并建立水质对土地利用结构的空间响应模型。由相关性分析得：从缓冲区尺度到子流域尺度,建设用地与氨氮的相关性由显著正相关变为高度正相关,相关系数达到0836;与高锰酸盐指数的相关性则由普通正相关变为显著正相关,相关系数为0776。耕地与高锰酸盐指数的相关性由显著正相关增加为高度正相关,相关系数达到0913;与氨氮的相关系数也增加到0782;而耕地与溶解氧则由缓冲区尺度的一般负相关变为子流域尺度的显著负相关,相关系数达0609。在缓冲区尺度上,林地与氨氮、高锰酸盐指数呈负相关,相关程度总体上随着缓冲半径的增大而增大;而当研究尺度为依自然属性划分的子流域时,林地与氨氮呈现出显著负相关,相关系数达到0673;与高锰酸盐指数呈现出高度负相关,相关系数达到0822;且在子流域尺度上林地对溶解氧的“汇”的作用才充分表现出来,相关系数达0718。研究结果表明：赤水河流域土地利用方式对水质有重要影响。赤水河流域内的城镇建设用地和耕地对流域水质有着严重的负面影响,承载在其上的城市生活、工业污水和农业面源污染(种养殖)是河流水质污染的重要污染源。林地对流域的水质污染有重要的缓解作用。总体上,各水质参数与土地利用类型间的相关性在子流域和缓冲区两种尺度下表现出一致的规律,但这种相关性在子流域尺度下表现的更为显著。研究成果可为赤水河流域的水污染防治、土地利用方式优化提供科学依据,并为同类研究提供借鉴     

土地整治视角下流域土地利用变化研究综述

研究目的:以流域为研究单元,从流域土地利用变化及其驱动力,流域土地利用模拟预测,流域景观格局变化及驱动力角度对已有的研究进行总结;而后将土地利用与景观格局改变对流域引发的生态环境影响进行理论总结与分析。研究方法:文献综述法。研究结果:在接下来的研究中应加强以下方面的研究工作:1加强对流域土地利用和景观格局变化驱动力对变化过程的累积效应研究;2强化对研究尺度与粒度探讨研究;3综合探讨土地利用与景观格局变化的关系及二者对流域的环境影响;4加强理论应用于实际的探索研究,优化流域土地合理利用与景观规划。     

土地利用变化对流域水文过程时空分异的影响 ——以赣江流域为例

土地利用变化引起的水文分量时空变化对认识流域产汇流过程,优化流域土地利用结构和水资源规划具有重要意义。基于SWAT模型,本研究以赣江流域为例,结合1980、2000、2015年3期土地利用数据从水文响应单元的角度,系统分析了单纯土地利用变化对流域产流、蒸发、入渗以及径流等主要水文过程时空分布的影响。结果表明：1980~2015年间,流域内的土地利用变化主要表现为耕地和林地的减少,城乡建设用地的增加;林地的减少和城乡建设用地的增加是产流增加,蒸发和入渗减少的主要原因;总体上,土地利用变化对局部地区水文过程影响较大,但因土地利用类型之间的相互转化和其影响的叠加,流域尺度上的综合水文效应明显降低;土地利用变化导致整个赣江流域平均径流量增加了2.33×108m3,相比较近年来赣江径流的减小幅度其影响十分有限。近年来,赣江入湖径流量的下降主要是由气候变化和其他人类活动作用特别是流域工农业用水的大幅增长所致。流域水文过程模拟应充分考虑土地利用变化水文效应的时空分异,注重天然和社会水循环的耦合,才能更为真实的反映流域水文过程,更好的为流域土地利用结构优化和水资源的高效管理提供科学依据。     

岷江流域土地利用结构对地表水水质的影响

当点源污染得到有效控制时,非点源污染,尤其是农业非点源污染将成为影响地表水水质的主要因素。利用遥感和地理信息系统技术获取岷江流域土地利用类型,并在分析该流域内地表水水质监测数据的基础上,研究了不同土地利用结构与地表水水质的相关关系。结果表明,在以单一土地利用类型为主控制的区域中,林地和草地控制的小流域的地表水水质明显优于耕地;在不同土地利用类型的组合结构中,地表水水质的优劣状况介于林地、草地和耕地为主控制的小流域之间;在其他条件相似时,随着小流域内林地和草地比例的增加,非点源污染降低,而随着耕地比例的增加,非点源污染有增大的趋势。此外,土地利用结构对地表水水质的影响不仅表现在数量结构上,同时表现在空间分布上.     

典型流域土地利用/覆被变化及对水质的影响--以太湖上游浙江西苕溪流域为例

利用1985、1995和20D0年的TM数据及水质资料，运用GIS和水质指数法研究西苔溪流域的土地利用／覆被变化及其水环境效应。结果表明：流域内耕地不断减少，建设用地持续扩大，林地前期减少后期缓慢增加；林地和耕地是流域内的主要土地利用类型，二者面积之和占流域面积的比例在三个时段均在92％以上；空间集中性及斑块碎化是土地利用空间格局变化的主要表现，建设用地斑块数量增多且斑块面积明显增大，饼地面积减少但斑块数量增多。研究时段内流域水质在时间上呈逐步恶化趋势，在空间上则表现为自上游至下游逐渐下降，其中，1996-2000年，研究河段内水质指数下降幅度达30％左右；只治理点污染源仅使水质指数增加6．5％左右，表明影响水质的主要因素是土地利用变化导致的面源污染。     

涑水河流域近18年土地利用/覆被变化及驱动力研究

本研究以涑水河流域的1990年和2008年两期TM影像为主要数据源,在ENVI和ArcGIS软件支持下,采用土地资源数量变化模型、土地利用转移矩阵和土地利用程度变化模型分析了涑水河流域18年间土地利用时空演变的情况及驱动机制。研究表明:涑水河流域林草地、耕地、建设用地呈现出较快增长的趋势,水域、未利用地呈现出逐渐减少的趋势;土地利用单一动态度变化不大,土地综合利用动态度为4.383。人口、政策以及城镇化经济增长是该流域土地利用/覆盖变化的主要驱动因子。     

怒江云南北段的村域土地利用及驱动力分析

驱动力分析是土地利用研究的重要内容。选择怒江流域北段高黎贡山自然保护区周边4个自然村为研究对象,应用高分辨率SPOT 5遥感影像数据,结合实地逐块核实,对土地利用/覆被进行分类,并建立土地利用类型分类系统,用Fragstats 33分析得到村域土地利用格局和特征;同时,采用入户调查、半结构访谈和问卷调查等方法,获得的村域详细社会经济数据,建立土地利用与社会经济之间的关联,分析村域土地利用的驱动力。结果显示：村域土地利用主要受自然条件、受教育程度、生活习俗等因子的驱动,且经济收入主要依赖于粗放的土地利用。研究结果能为怒江云南北段的土地资源合理利用和村域经济发展提供数据支持;研究方法可作为局域尺度土地利用研究的参考     

后寨河流域岩溶含水层脆弱性及其对土地利用方式的响应

由于强烈的溶蚀作用,岩溶地区溶蚀裂隙、管道等高度发育,并相互贯通,形成岩溶区特有的地下、地表“双层空间”结构体系,地下空间成为地下水存储和运移的重要场所。岩溶地区由于土层浅薄或缺失,并且溶蚀裂隙、管道、落水洞、竖井等高度发育,使含水层更易受地表状况的影响,土地利用/覆被变化在很大程度上影响着地下水的水质、水量,岩溶水质的变化能集中反映人类活动胁迫下岩溶含水层脆弱性程度的增加。以典型岩溶单元--贵州普定后寨河流域为例,分析了流域水文地质背景下的岩溶含水层本质脆弱性,结合流域地下河水近20年的水化学资料,分析了含水层脆弱性对土地利用变化的响应。结果显示：土地利用/覆被变化、农业活动、城镇建设及居民活动都对地下水质变化有明显影响。因此,调整土地利用结构,恢复岩溶植被,改善生态环境是保护和改善岩溶水资源的重要途径。     

长江中游城市群土地利用转型和城镇化之间的空间关系

城市群正成为中国新型城镇化主体形态,城市群集聚区的快速城镇化对土地利用转型产生了前所未有的影响。但是不清楚的土地利用转型特征和城镇化之间的空间关系,会影响土地利用政策制定和城镇化的健康发展。该文借助1995～2015年间5期土地利用现状遥感监测数据,在5和10 km格网尺度上,从土地利用综合动态度、土地利用程度和土地利用多样性等3方面测度了长江中游城市群土地利用转型水平。借助普通最小二乘法（OLS）、空间滞后模型（SLM）、空间误差模型（SEM）和加入空间滞后项的空间误差模型（SEMLD）探测了土地利用转型和城镇化之间的空间和非空间关系。研究结果显示：（1）1995～2015年间长江中游城市群土地利用发生了深刻转型,耕地面积净减少 6 153.80 km²,建设用地面积净增加 6 205.25 km²;（2）地级市以及周边格网和主要的交通道路沿线格网土地利转型速度、土地利用程度变化和土地利用多样性变化显著高于其他地区;（3）不同格网尺度城镇化和土地利用转型之间具有显著的正向空间自相关关系;（4）回归结果显示,SEMLD模型可以更好地解释土地利用转型与城镇化之间的空间关系,在不同尺度回归分析中发现土地利用转型水平对城镇化具有显著的空间依赖性。未来的土地利用管理以及城镇化发展中需要考虑二者之间的显著的空间依赖性。     

太湖流域水供给服务供需时空演变分析

太湖流域是我国经济发展最快、人口最密集的地区之一。受土地利用和降水条件变化的影响,太湖流域水供给服务供需关系也发生着变化。通过分别设置1995～2015年太湖流域不同降水条件和土地利用变化情景,利用Invest模型定量评估水资源供给量,同时利用空间离散法定量评估水资源需求量,并进一步分析供需赤字和盈余区域的时空变化。结果表明:1995～2015年随着土地利用变化,尤其是建设用地的扩张(20年来涨幅达106%),水资源需求占供给量的比重由73%升至90%,需要依赖外来客水的县域面积占整个流域的比重由19%升至33%;2015年在不同降水条件下供需关系变化更为明显,降水量越少,供需赤字的县域越多,在干旱年份整个流域需求量占供给量的117%,供给量已不能满足需求量,且赤字县域的面积占整个流域的47%。两种情境下,太湖流域东北部水供给服务供需关系均比西南部紧张。作为影响太湖流域水资源供需变化的主要因素,土地利用和降水条件变化分别通过影响需求量和供给量改变供需关系。     

An agent-based model of groundwater over-exploitation in the Upper Guadiana, Spain

Irrigated agriculture is a main user of groundwater. Achieving a sustainable use of groundwater will often require agricultural land-use changes such as shifting to entirely different kinds of crops and/or technologies. Enhanced understanding of land-use change is hence required for developing policies for a sustainable water future. We use an agent-based model to investigate the history of irrigated agriculture in the Upper Guadiana Basin, Spain, in order to learn about the influence of farmers’ characteristics on land-use change and associated groundwater over-use. A shift from vineyards and cereals to horticultural crops would provide a possibility for higher income with less water use. Such a shift cannot be observed historically. The model results suggest that risk aversion and path dependency are insufficient to explain this observation, and the organisational set-up of farms limiting the maximum labour force needs to be considered as additional explanatory factor. Furthermore, it is shown that different types of farms existing in the UGB can be expected to exhibit distinct responses to drivers of land-use change such as agricultural policies. It is concluded that a sound understanding of the social system making use of a resource is required to solve problems of resource over-use. This article demonstrates that agent-based models can be useful tools to enhance such an understanding even in situations of scarce and uncertain data that are often encountered when dealing with resource-use problems.     

Development of a land-use forecast tool for future water resources assessment: case study for the Mekong River 3S Sub-basins

Land-use change is one of the major factors that alter local and regional hydrology. For areas experiencing fast expansion of urban and agriculture areas, land-use changes often adversely affect stream flow and water resources at the local and watershed scale. The Sekong, Sesan, and Srepok (3S) Sub-basins are a part of the Lower Mekong River Basin and include land in Cambodia, Lao People’s Democratic Republic (Laos), and Viet Nam. The region is experiencing a dynamic land-use transition because of rapid changes in its economy, society, and environment. Major land-use changes include deforestation of native rain forest, expansion of agricultural and urban areas, and expansion of commercial plantation such as rubber trees. These land-use alterations have affected local and regional hydrologic processes, resulting in stream flow shortages during the dry season and flash flooding due to deforestation. In this research, deforestation in the 3S Sub-basins over the period 1993–1997 was analyzed using multi-logistic regression. The regression analysis indicated that density of agricultural cells within a 5-km radius from each forest cell and slope strongly affected the deforestation process. A land-use forecast model to simulate deforestation and urbanization sites was developed in GIS based on local land-use change trends. The model was applied to 2003 land use to forecast 2033 land use and future water demand, which was further compared with present stream flow measurements during the dry season at various places in the region. The entire approach from the land-use forecast to its impact assessment on stream flow could help local stakeholders understand watershed-wide future water resources risks and develop future water resources plans. With the 3S Sub-basins being used as a case study area, this article presents a land-use forecast tool; simulated 2033 land-use and water demand; and the estimation of the impact of the forecasted future water demand on the local stream flow.     

A Methodology Framework for Regional Land-use Change Studies based on Landsat TM images: A Case Study in Northeast China

Land-use change is an important aspect of global environment change. It is, in a sense, the direct result of human activities influencing our physical environment. This paper analyzed the land-use change in Northeast China during 1985-2000 based on Landsat TM images. It divides Northeast China into five land-use zones based on the dynamic degree model of land-use: woodland/grassland-arable land conversion zone, dry land-paddy field conversion zone; urban expansion zone, interlocked zone of farming and pasturing and reclamation and abandon zone. The findings include the obvious increase of cropland area, paddy field and dry land increased by 75 and 276 thousand hm2 respectively; urban areas expanded rapidly, areas of town and rural residence increased by 76.8 thousand hm2; areas of forests and grassland decreased sharply with the amounts of 1399 and 1521 thousand hm2 respectively; areas of water body and unused land increased by 148 and 514 thousand hm2 respectively. This paper also discusses the driving     

Climate change adaptation,flood risks and policy coherence in integrated water resources management in England

Integrated water resources management (IWRM) assumes coherence between cognate aspects of water governance at the river basin scale, for example water quality, energy production and agriculture objectives. But critics argue that IWRM is often less ‘integrated’ in practice, raising concerns over inter-sectoral coherence between implementing institutions. One increasingly significant aspect of IWRM is adaptation to climate change-related risks, including threats from flooding, which are particularly salient in England. Although multiple institutional mechanisms exist for flood risk management (FRM), their coherence remains a critical question for national adaptation. This paper therefore (1) maps the multi-level institutional frameworks determining both IWRM and FRM in England; (2) examines their interaction via various inter-institutional coordinating mechanisms; and (3) assesses the degree of coherence. The analysis suggests that cognate EU strategic objectives for flood risk assessment demonstrate relatively high vertical and horizontal coherence with river basin planning. However, there is less coherence with flood risk requirements for land-use planning and national flood protection objectives. Overall, this complex governance arrangement actually demonstrates de-coherence over time due to ongoing institutional fragmentation. Recommendations for increasing IWRM coherence in England or re-coherence based on greater spatial planning and coordination of water-use and land-use strategies are proposed.

     

A Methodology Framework for Regional Land-use Change Studies based on Landsat TM images: A Case Study in Northeast China

Abstract

Land-use change is an important aspect of global environment change. It is, in a sense, the direct result of human activities influencing our physical environment. This paper analyzed the land- use change in Northeast China during 1985–2000 based on Landsat TM images. It divides Northeast China into five land-use zones based on the dynamic degree model of land-use: woodland/grassland-arable land conversion zone, dry land-paddy field conversion zone; urban expansion zone, interlocked zone of farming and pasturing and reclamation and abandon zone. The findings include the obvious increase of cropland area, paddy field and dry land increased by 75 and 276 thousand hm² respectively; urban areas expanded rapidly, areas of town and rural residence increased by 76.8 thousand hm²; areas of forests and grassland decreased sharply with the amounts of 1399 and 1521 thousand hm² respectively; areas of water body and unused land increased by 148 and 514 thousand hm² respectively. This paper also discusses the driving forces in each land-use dynamic zone and finds that some key biophysical factors affect conspicuously the conversion of different land-use types. The relation between land-use conversion and DEM, accumulated temperature (≤10°C) and precipitation was analyzed and represented. The land-use changes In Northeast China resulted from the changing macro social and economic factors and local physical elements. Rapid population growth and management changes can explain the shaping of woodland/grassland-cropland conversion zone. The conversion from dry land to paddy field in the dry land-paddy field conversion zone, apart from the change of physical elements promoting the expansion of paddy field, results from two reasons: one is that the implementation of market economy in China has given farmers the right to decide what and how they plant their crops, the other factor is originated partially from the change of the dietary habit along with the social and economic development. The conversion from paddy field to dry land is caused primarily by the shortfall of irrigation water, which in turn is caused by poor water allocation managed by local governments. The shaping of the reclamation and abandon zone is partially due to the lack of environment protection consciousness among pioneer settlers. The reason for the conversion from grassland to cropland is the relatively higher profits of farming than that of pasturing in the interlocked zone of farming and pasturing. In Northeast China, the rapid expansion of built-up areas results from two factors: the existence of a small number of towns and the huge potential for expansion of the existing towns and cities. The urban land expanded mainly in areas with a gentle topographic relief and low population density.     

Modeling changes in paddy rice sown areas in Asia

Paddy rice fields in Asia account for over 90% of global total rice cultivation area, and the major rice-producing countries of Asia account for over one-half of the world’s population. Monitoring and understanding the dynamic changes in paddy rice agriculture in Asia are very important for agricultural sustainability, food and water security, and greenhouse gas emissions. This paper presents a crop choice decision model that dynamically simulates future changes in sown areas of paddy rice in Asia. This model was developed under the framework of Action-in-Context (AiC) with the aim of understanding land users’ decisions on crop choices among a set of available alternatives using a crop utility function. Empirical validation for the model conducted after model construction indicated the reliability of the model for addressing the complexity of current agricultural land-use change and its capacity for investigating long-term scenarios in the future. Finally, the model was applied for future scenario analysis over a time frame of 30 years with 5-year increments, beginning from the year 2005. The simulation results provided insights into rates and trajectories of changes in Asian rice areas over the test period, with the resulting implications for future agricultural sustainability in Asia. These outcomes can improve understanding of projected land-use changes and explain their causes, locations and consequences, as well as providing support for land-use planning and policy making.     

流域土地利用变化的长周期水文效应及管理策略

长周期水文效应作为不同强度暴雨事件的综合反映，对流域规划和管理决策非常重要。以太湖地区蠡河流域为研究区，通过解译1984年、1995年和2000年3个时段TM/ETM获得土地利用分布地图，分析其土地利用变化的模式，并基于研究区30年的降水序列，应用长周期水文分析模型L-THIA（Long-Term Hydrologic Impact Assessment），计算3个时段土地利用特征对暴雨地表径流的影响，分析不同土地利用类型水文效应的敏感性，在此基础上总结了减少流域水文效应的土地利用管理策略。分析结果显示，该区土地利用有明显变化，主要表现为水田、旱田向建筑用地的转化，从1984年到2002年，城镇及居民地扩展占流域总面积的4.199 4 ％，地表径流量增加了6.170 ％，不同土地利用方式的水文效应有较大差别，林地、湖滩湿地的敏感性最大，其次是水田和旱田。     

干旱地区土地利用结构变化与生态服务价值的关系研究——以酒泉市为例

利用酒泉市1997-2006年土地利用变更调查数据和相关统计资料,计算土地利用结构异质性指数和生态服务价值,分析土地利用结构与生态服务价值的变化及其相互关系.结果表明:1997-2006年酒泉市耕地、林地、园地面积在增加,其中耕地增加最多,增加了9 803.15hm2,牧草地、水域和未利用地面积不断减小,其中牧草地减少最多,减少了207 470.56 hm2;酒泉市土地利用结构多样性指数和均匀度增加而优势度降低,土地利用趋于多样化和均匀化;各类土地的生态服务价值都有不同程度的增加,土地利用生态服务价值总体呈增加趋势;土地利用生态服务价值与土地利用结构线性相关,通过增加牧草地、水域和耕地等生态用地面积,提高土地利用集约度,调整土地利用结构促进土地利用的多样化、均匀化,可以增加生态系统稳定性和提高生态系统服务功能的经济价值.     

湖北省近期土地利用变化的遥感分析

土地利用，覆盖变化研究是全球变化研究的前沿和热点之一。采用遥感、GIS一体化技术．利用1989～1990年和1999～2000年获取的陆地资源卫星图像，建立了湖北省近10年来两个不同时期的同比例尺土地利用动态变化数据库，并对变化的时空特征进行了分析。结果表明，耕地减少了0．68％，林地减少了0．18％，各类建设用地总计增加了。7．92％．水域面积增加的幅度为3．01％。土地利用与土地覆盖变化的转型主要发生于上述4类之中．尤其是耕地与水域相互之间的转变比较频繁。动态度计算表明，土地利用变化最快的区域均处于大中城市及其周边地区；江汉平原、鄂东的大部分地区及鄂西的宜昌．土地利用变化较快；鄂西山区绝大部分、大别山区部分县及鄂东南幕阜山区的通山县，土地利用变化不大。