基于友好度函数的流域初始水权分配模型

针对目前流域初始水权分配模型中指标体系不一致的问题,提出了初始水权分配友好的概念,并确定了粮食安全保障原则、生态用水保障原则、尊重历史与现状原则、公平性原则、高效性原则以及环境保护原则作为初始水权分配的具体原则,建立了基于各原则的初始水权分配友好度子函数,提出了以初始水权分配系统友好度最大为目标的友好度分配模型。将此模型应用到湖北省府环河流域初始水权分配中,结果表明,该模型概念清晰,无需构造指标体系,可有效避免指标体系非一致性问题,同时能定量表达初始水权的分配过程及初始水权分配中各要素之间的友好关系,所建立的模型为流域初始水权分配的研究提供了一种新方法。     

考虑水转化过程的干旱区内陆河流域适宜灌溉规模

农业适水发展是保障干旱区水土资源高效利用和生态健康的关键,其核心在于如何科学确定灌溉规模,进而控制农业灌溉用水量。该研究以石羊河流域为研究区,在明确非灌溉需水量的基础上,基于水均衡模型计算考虑水转化过程的不同水文年农业灌溉可用水量,并构建多目标种植结构优化模型对作物种植结构进行调整,最后改进水热平衡模型构建考虑水转化过程的旱区适宜灌溉规模计算模型,分析流域不同情景下的适宜灌溉规模。结果表明：地表水地下水联合调控下,石羊河流域丰、平、枯水年的灌溉可用水量分别为18.97亿～21.57亿、14.75亿～17.51亿、12.31亿～14.95亿m³;优化作物种植结构后能够以减少2.94%的经济效益实现14.13%的灌溉节水;构建的适宜灌溉规模计算模型在干旱区内陆河流域具有较好的适用性,采用该方法得到现状条件下石羊河流域丰、平、枯水年的适宜灌溉规模分别为27.73万～31.66万、21.55万～25.76万、18.01万～22.03万hm²,提高节水水平、调整种植结构后,流域的适宜灌溉规模有所增加。现状2020年(平水年)的实际灌溉面积高于当地水资源...     

Adaptive management frameworks for natural resource management at the landscape scale: implications and applications for sediment resources

Purpose  

The management of natural resources over large spatial scales is inherently complex due to numerous biophysical and socioeconomic factors and the uncertainty associated with environmental systems and human behavior. Numerous approaches have been put forward to facilitate the decision-making process, including adaptive management (AM) which was developed in the 1960s and 1970s as an alternative to more rigid management frameworks. In recent years, it has been utilized for the management of water and river basin resources, particularly in North America. Its use for sediment resources is less well developed. This paper presents a review of the AM approach, including its characteristics, steps, and barriers to implementation. It also gives some recent examples where the AM approach has been used for sediment quantity and quality issues. Finally, it considers the potential of the AM approach for sediment resource management given Water Framework Directive and other legislative requirements.     

渭河(咸阳段)表层沉积物中重金属形态分布特征

采用欧共体修正BCR四步连续提取法对渭河(咸阳段)的表层沉积物的重金属(Pb,Cr,Cu,Ni,Mn和Zn)形态进行了研究.结果表明,Cr,Ni和Zn主要以残渣态的形式存在,分别为97.91%,66.36%和73.68%,表现出很高的稳定性.而Pb和Mn仅在乙酸提取态含量分别达27.66%和38.49%时表现出一定的生物有效性和潜在危害性."非稳定态"重金属的空间分布特征是沣河渭河交汇处上游位含量最高,其次为渭河3号桥下,沣河渭河交汇处下游含量最低.     

Deriving river networks and catchments at the European scale from medium resolution digital elevation data

The extraction of drainage networks and catchment boundaries from digital elevation models (DEMs) has received considerable attention in recent years and is recognized as a viable alternative to traditional surveys and the manual evaluation of topographic maps. However, most studies have covered limited areas due to the lack of detailed information and/or the lack of highly efficient algorithms. In this paper we present an application that delineates river networks and catchment boundaries across the European continent from a medium resolution (250 m) DEM. We exploit novel algorithms based on the concepts of mathematical morphology and implement a landscape stratification for drainage density.A flow direction grid is computed using an efficient algorithm for the removal of spurious pits. River networks are then derived by imposing a variable threshold for the minimum contributing area needed to form and maintain a channel. This is achieved through a landscape stratification that reflects the ability of the terrain to develop different drainage densities. It is shown that the analysis of environmental characteristics coupled with the analysis of local slope versus contributing area enables river network mapping with a spatially varying drainage density. The result has been validated by comparing the derived data to digital river and catchment data from other sources and with varying scales of observation.     

Phosphorus transfer across boundaries: from basin soils to river bed sediments

Purpose  

The study of phosphorus (P) transfer from soils to rivers is a subject of interest as there is a clear relation between land use and water quality. P transfer in the soil/sediment system was evaluated by comparing the concentrations of total (P_T) and bioavailable P (P_A).     

上方来水来沙对细沟侵蚀产沙过程的影响

利用双土槽系统径流小区 (供沙土槽和试验土槽 ),定量研究了不同上方来水含沙量和不同降雨强度下 15^°坡面上方来水来沙对坡下方细沟侵蚀产沙过程的影响。结果表明,坡上方来沙量不但被径流全部搬运,且坡上方来水在坡下方细沟侵蚀槽引起另外的侵蚀产沙量 S。坡面细沟侵蚀过程以侵蚀—搬运过程为主。上方来水对细沟侵蚀产沙的贡献受上方来水含沙量和降雨强度的影响。降雨强度的增加或上方来水含沙量的减少,使 S值的增加更为显著.     

上方来水来沙对细沟侵蚀产沙过程的影响

利用双土槽系统径流小区 (供沙土槽和试验土槽 ) ,定量研究了不同上方来水含沙量和不同降雨强度下 15°坡面上方来水来沙对坡下方细沟侵蚀产沙过程的影响。结果表明 ,坡上方来沙量不但被径流全部搬运 ,且坡上方来水在坡下方细沟侵蚀槽引起另外的侵蚀产沙量 S。坡面细沟侵蚀过程以侵蚀—搬运过程为主。上方来水对细沟侵蚀产沙的贡献受上方来水含沙量和降雨强度的影响。降雨强度的增加或上方来水含沙量的减少 ,使 S值的增加更为显著     

基于不同PTF_S的流域尺度土壤持水特性空间变异性分析

利用点估计模型、线性回归模型、非线性回归模型和人工神经网络模型等四种PTFS分别预测大沽河流域90个土壤样本的田间持水量(θ-30 kPa)和凋萎含水量(θ-1 500 kPa),借助传统统计学和地统计学方法对其空间变异性进行了比较分析。传统统计学分析认为非线性回归模型预测的效果最好,无论是实测值还是估计值,所有土壤样本θ-30 kPa的变异系数总是小于θ-1 500 kPa,两者均属于中等变异性;地统计学分析表明实测值和预测值的θ-30 kPa和θ-1 500 kPa均存在不同程度的块金效应,且θ-30 kPa总是表现出较θ-1 500 kPa更强烈的空间相关性,通过分析θ-30 kPa和θ-1 500 kPa的半方差函数模型参数,发现人工神经网络模型最能真实地反映试验区土壤持水特性的空间变异性特征。     

汀江长汀段水沙变化及其与水土保持关系探讨

对汀江流域长汀段1972~2014年共43年实测资料统计、分析,结果表明:汀江长汀段降雨量主要集中在3~6和8月间,径流和输沙量也集中在这段时间,反映了该流域水沙年内分配一致性的特点;汀江长汀段径流和输沙量都有显著的上升和下降波动,突变年份并不完全一致,相同的是在2000年后,径流和输沙都有明显的下降趋势;对水土流失治理前后期的年均水沙变化及相同降水条件下水土流失治理前后期的水沙变化分析表明,水土保持对流域水沙影响较大,做好水土保持可以减少输沙量。     

Soil nitrogen balance and nitrogen utilization of winter wheat affected by straw management and nitrogen application in the Yangtze river basin of China

Straw incorporation is a useful management practice in sustainable agricultural systems to improve soil fertility and to reduce air pollution from straw burning. A three-year field experiment was conducted under two rice straw managements and four nitrogen (N) application rates in Rugao, China during 2010–2013, to examine whether straw management practices integrated with fertilizer N applications affect crop yield, N balance and N use efficiency in the wheat season of rice-wheat cropping systems. The results showed that straw incorporation had positive effects on plant N uptake and grain yield. This may be attributed to the greater soil water content and lower amount of seasonal rainfall. However, straw incorporation resulted in lower soil inorganic N and more N surplus at the early growth stage. Grain yield had a significant relation with wheat N uptake from sowing to jointing and from jointing to anthesis with straw incorporation. Therefore, our results suggest that in adjusting the ratio of basal and topdressing N fertilizer, it is important for the supply of optimum N to the crop and to maintain grain production with straw incorporation.     

Application of an incomplete factorial design for the formation of an autotrophic biofilm on river bed sediments at a microcosms scale

Purpose  

River bed sediments are often colonized by microorganisms which can produce large amounts of extracellular polymeric substances (EPS) forming biofilms that may increase the resistance of the bed sediment towards erosion and affect the nutrient and pollutant exchange between water and sediments. The objective of this work was to study the influence of organic carbon, ionic concentration (NaCl) and N/P ratio on the growth of autochthonous biomass and the production of EPS in autotrophic biofilms by measuring the extracellular carbohydrates produced, a specific component of the EPS.     

岷江上游1974-1995年间景观变化

Landscape changes were traced over the 20 years from 1974 to 1995 in the upper Minjiang River basin, one of the most important forest regions in China, based on satellite image interpretation to provide basic data for local decision-making as well as sustainable landscape use and management. Results revealed that landscape from 1974 to 1995 changed at the regional scale as the area of forestland decreased, while cropland, shrubland, economic forest, grassland, and built-up land increased. Landscape changes mainly occurred in forestland, shrubland, grassland, economic forest, and built-up land. Moreover, the changes among forestland, shrubland, and grassland were the largest, influencing the whole characteristics of the changes in the basin. Analysis of the changes between 1974 and 1995 in the study area indicated that landscape heterogeneity and fragmentation increased, whereas landscape connectivity decreased. There were multiple reasons for landscape changes. A principal component analysis （PCA） was used to quantitatively study driving forces of landscape changes. The PCA results showed that economic and population factors were the principal driving forces of landscape changes from 1974 to 1995 in the upper Minjiang River basin, and that PCA was a suitable method for investigating driving forces of landscape changes.