Modeling the Linkage Between River Water Quality and Landscape Metrics in the Chugoku District of Japan

The present study was conducted using secondary database, remote sensing, geographical information system (GIS) and multivariate analysis tools in order to develop Multiple Linear Regression (MLR) models that could be able to predict level of water quality variables using compositional and spatial attributes of land cover in the river basins. The study encompasses 21 river basins with 32 000 Km² area, located in the Chugoku district in West Japan. Biological Oxygen Demand (BOD), pH, Dissolved Oxygen (DO), Suspended Solid (SS), Total Nitrogen (TN), and Total Phosphorus (TP) were considered as water quality variables of the stream. Satellite data was used to generate the land cover map of the study area. MLR models were developed using the compositional (%) and spatial attributes (landscape metrics) of the land cover at watershed and class levels for representing the land cover-stream water quality linkage. The results of the MLR modeling using the land cover data at the class level revealed that 92%, 74% and 62% of the total variations in concentration of DO, pH and TP were explained by changes in the measure of the spatial attributes of the land cover at the class level in the study area. These models can help local and regional land managers to understand the relationships between the compositional attribute (%) and the spatial features of the land cover and river water quality and would be applied in formulating plan for watershed-level management.     

The Importance of Riparian Forest Cover to the Ecological Status of Agricultural Streams in a Nationwide Assessment

Forested riparian corridors are a key management solution for halting the global trend of declining ecological status of freshwater ecosystems. There is an increasing body of evidence related to the efficacy of these corridors at the local scale, but knowledge is inadequate concerning the effectiveness of riparian forests in terms of protecting streams from harmful impacts across larger scales. In this study, nationwide assessment results comprising more than 900 river water bodies in Finland were used to examine the importance of adjacent land use to river ecological status estimates. Random forest models and partial dependence functions were used to quantify the independent effect of adjacent land use on river ecological status after accounting for the effects of other factors. The proportion of adjacent forested land along a river had the strongest independent positive effect on ecological status for small to medium size rivers that were in agricultural landscapes. Ecological quality increased by almost one status class when the adjacent forest cover increased from 10 to 60%. In contrast, for large rivers, adjacent forested land did not show an independent positive effect on ecological status. This study has major implications for managing river basins to achieve the EU Water Framework Directive (WFD) goal of obtaining good ecological status of rivers. The results from the nationwide assessment demonstrate that forested riparian zones can have an independent positive effect on the ecological status of rivers, indicating the importance of riparian forests in mitigating the impacts of catchment-level stressors. Therefore, forested buffer zones should be more strongly considered as part of river basin management.

     

Runoff Changes in the Šumava Mountains (Black Forest) and the Foothill Regions: Extent of Influence by Human Impact and Climate Change

The main aim of our research project was to determine the extent to which the outflow can be influenced by human interventions in three selected water basins in the Šumava Mountains (Black Forest) and its foothills. The rainfall-runoff analyses using both the single-mass and double-mass curves over the period of hydrologic observations were taken as a preliminary methodology. Standard statistical testing methods Wilcoxon and Mann–Kendall non-parametric tests were applied to detect the trends. Besides mean discharge, precipitation, snow and air temperature trends, analysis of land cover change and human impact on the river network and development of drainage areas were also carried out. The greatest deviations were widely observed in the period between the second half of the 1970s and the first half of the 1980s. The whole system came slowly back to its initial condition in the early 1990s. The runoff trend deviation was related to natural and human factors, mainly to current climatic changes, river network modification and changes of land cover.     

水贫乏指数的概念及其在中国主要流域的初步应用

介绍了水贫乏指数WPI(Water Poverty Index)的概念及其计算方法,指出WPI是一种可以定量评价国家或地区间相对缺水程度的综合性指标。该指标考虑了资源、工程、管理、经济、环境等多方面因素,具体包括5个要素：即潜在水资源状况、供水设施状况、利用能力、使用效率和环境状况。本文将改进的WPI均衡计算方法应用于我国主要流域,结果表明,辽河、海河、淮河、黄河流域的缺水程度严重,长江和珠江流域的缺水程度相对较低,与我国水资源的客观状况基本相符,基本反映了我国各大流域间的相对缺水现状及相应的水资源管理水平。最后,依据WPI各要素的雷达图,初步分析了导致各流域缺水的主要原因和威胁其水资源安全的主要因素。另外,文中对 WPI方法的适用性和有待改进之处也进行了讨论。     

Basin-wide Water Resources Planning by Integrating PSO Algorithm and MODSIM

Water resources planning and management at basin scale is such a large and complex problem that makes it essential to use effective modeling tools in order to obtain an optimum plan for river basins development. In this paper, a methodology is presented for optimized design and operation of the upstream Sirvan basin in Iran. The model proposed integrates MODSIM generalized river basin network flow model, with the capability of simulating various characteristics and features of water resources in a river basin, and Particle Swarm Optimization (PSO) algorithm. In the developed PSO-MODSIM model, the size of planned dams and water transfer systems, as design variables, and the relative priorities for meeting reservoir target storages, as operational variables, are varied and evolved using PSO algorithm. MODSIM is called to simulate the system performance and to evaluate the fitness of each set of those design and operational variables with respect to the model’s objective function. The PSO objective function is to maximize the total net benefit consisting of benefits due to supplying water to different types of water uses and construction costs of dams and water transfer and/or pumping systems. Varying the design and operational variables in MODSIM 8 is done using the MODSIM’s custom coding feature in VB.NET routine. The PSO-MODSIM model is used to size the planed water storage and transfer components of a river basin system and to allocate water resources optimally over time and space among competing demands, considering coordinated operation of the system components. The model results has been analyzed for different scenarios of water transfer from Sirvan to neighboring basins.     

Simulation of overflow thresholds in urban basins: Case study in Tuxtla Gutiérrez,Mexico

The space–time dynamics and the effect of urban growth on territory transformation were simulated with Iber 2D to analyze flooding events in the lower basin of the Sabinal River, Mexico. We classified the main coverages and land uses of the study area. Soil roughness and water infiltration in the soil were evaluated. Both values were used as input data in a simulation model with Iber 2D to analyze and compare the levels of water height and maximum flood level area with different precipitation values in two reference years, 1986 and 2014. Residential use land cover increased considerably while tree, pasture and agricultural use covers decreased. Consequently, in 2014, precipitation of similar magnitude led to higher values of direct runoff, increasing water levels and therefore the risk of overflowing. The water levels and moments of river overflow provided feedback for flood‐risk warning systems and tools to monitor basins lacking adequate infrastructure.     

PAST AND PREDICTED FUTURE CHANGES IN THE LAND COVER OF THE UPPER MISSISSIPPI RIVER FLOODPLAIN,USA

This study provides one historical and two alternative future contexts for evaluating land cover modifications within the Upper Mississippi River (UMR) floodplain. Given previously documented changes in land use, river engineering, restoration efforts and hydro‐climatic changes within the UMR basin and floodplain, we wanted to know which of these changes are the most important determinants of current and projected future floodplain land cover. We used Geographic Information System data covering approximately 37% of the UMR floodplain (3232 km²) for ca 1890 (pre‐lock and dam) and three contemporary periods (1975, 1989 and 2000) across which river restoration actions have increased and hydro‐climatic changes have occurred. We further developed two 50‐year future scenarios from the spatially dependent land cover transitions that occurred from 1975 to 1989 (scenario A) and from 1989 to 2000 (scenario B) using Markov models. Land cover composition of the UMR did not change significantly from 1975 to 2000, indicating that current land cover continues to reflect historical modifications that support agricultural production and commercial navigation despite some floodplain restoration efforts and variation in river discharge. Projected future land cover composition based on scenario A was not significantly different from the land cover for 1975, 1989 or 2000 but was different from the land cover of scenario B, which was also different from all other periods. Scenario B forecasts transition of some forest and marsh habitat to open water by the year 2050 for some portions of the northern river and projects that some agricultural lands will transition to open water in the southern portion of the river. Future floodplain management and restoration planning efforts in the UMR should consider the potential consequences of continued shifts in hydro‐climatic conditions that may occur as a result of climate change and the potential effects on floodplain land cover. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.     

艾比湖水盐变化及其影响研究

从湖泊水文要素出发，基于湖泊和流域的关系，对半个世纪以来艾比湖面积、矿化度等水文要素变化趋势进行了分析，并对变化原因进行了探讨。结果表明：相对封闭及较小尺度的流域面积等自身特性，决定了其水资源系统自我调节能力的脆弱性；而近年流域内的人类活动，增大了降水径流的滞留时间和蒸发作用，最终导致汇入湖泊的水量不断减少，矿化度在湖水量不断减少的情况下浓缩升高。     

Evaluating the application of a decision support system in identifying adequate wastewater treatment for small communities. A case study: the Fluvia River Basin.

The identification of adequate wastewater treatment for small communities is a complex problem since it demands a combination of data from different sources, such as aspects of the community and landscape, the receiving environment and the available wastewater treatment technologies. The Catalan Water Agency (Agència Catalana de l'Aigua) considered using an EDSS (Environmental Decision Support System) as a tool to help water managers select the most adequate treatment for the urban wastewater of nearly 3,500 small communities in Catalonia (Spain). From that moment, EDSS was applied to all the river basins in Catalonia. In this paper the authors present the results obtained for the 76 small communities located in one of these river basins: the Fluvia River Basin. The characteristics of the community used in the reasoning process of the EDSS, the list of selected wastewater treatment alternatives, the technical environmental justification for the selected treatments and the reasons for discarding, favouring or disadvantaging them are presented. Finally, some results for the Fluvia River Basin are compared with those obtained in other Catalan river basins with different characteristics in order to evaluate which are the significant features in identifying adequate wastewater treatments.     

A Pilot Global Assessment of Environmental Water Requirements and Scarcity

Abstract

This paper presents a first attempt to estimate the volume of water required for the maintenance of freshwater-dependent ecosystems at the global scale. This total environmental water requirement consists of ecologically relevant low-flow and high-flow components and depends upon the objective of environmental water management. Both components are related to river flow variability and estimated by conceptual rules from discharge time series simulated by the global hydrology model. A water stress indicator is further defined, which shows what proportion of the utilizable water in world river basins is currently withdrawn for direct human use and where this use is in conflict with environmental water requirements. The paper presents an estimate of environmental water requirements for 128 major river basins and drainage regions of the world. It is shown that approximately 20 to 50 percent of the mean annual river flow in different basins needs to be allocated to freshwater-dependent ecosystems to maintain them in fair conditions. This is unlikely to be possible in many developing countries in Asia and North Africa, in parts of Australia, North America, and Europe, where current total direct water withdrawals (primarily for irrigation) already tap into the estimated environmental water requirements. Over 1.4 billion people currently live in river basins with high environmental water stress. This number will increase as water withdrawals grow and if environmental water allocations remain beyond the common practice in river basin management. This paper suggests that estimates of environmental water requirements should be the integral part of global water assessments and projections of global food production.     

Modelling physical characteristics of river habitats

The physical characteristics of river habitats constitute the setting in which fluvial biota dwell and thrive. Determining the spatial and temporal patterns of physical habitat characteristics and the main factors that control them is extremely important to increase the efficiency of river management, conservation, and restoration. This study determined spatial patterns of physical habitat characteristics for Atlantic and Mediterranean rivers in northern Spain and developed a river classification based on hydromorphological characteristics. Data gathered from almost 600 sites following a modified version of the River Habitat Survey methodology were used. In addition to the usual River Habitat Survey variables, the sequence of hydromorphologic units (i.e., areas exhibiting similar hydraulic characteristics, in terms of water velocity and depth), water depths, and widths were recorded. Unmodified reaches were selected computing the Habitat Modification Score. Multiple Linear Regression models were employed to test relationships between Principal Component Analyses that summarized physical river habitat characteristics with ecological relevance and environmental variables (i.e., climate, topography, land cover, and geology) at different spatial scales and used to predict physical habitat attributes for all river reaches. The density of hydromorphologic units, flow turbulence, substrate size, and channel dimensions were able to discriminate river classes within the river network, with topography being the main environmental driver of habitat characteristics (although climate, geology, and land cover were also relevant). This classification scheme could constitute a useful tool to restore physical habitat conditions in modified river reaches.     

Optimal Inter-Basin Water Allocation Using Crisp and Fuzzy Shapley Games

In recent years, uneven distribution of available water resources as well as increasing water demands and overexploiting the water resources have brought severe need for transferring water from basins having sufficient water to basins facing water shortages. Therefore, optimal allocation of shared water resources in water transfer projects, considering the utilities of different stakeholders, physical limitations of the system and socioeconomic criteria is an important task. In this paper, a new methodology based on crisp and fuzzy Shapley games is developed for optimal allocation of inter-basin water resources. In the proposed methodology, initial water allocations are obtained using an optimization model considering an equity criterion. In the second step, the stakeholders form crisp coalitions to increase the total net benefit of the system as well as their own benefits and a crisp Shapley Value game is used to reallocate the benefits produced in the crisp coalitions. Lastly, to provide maximum total net benefit, fuzzy coalitions are constituted and the participation rates of water users to fuzzy coalitions are optimized. Then, the total net benefit is reallocated to water users in a rational and equitable way using Fuzzy Shapley Value game. The effectiveness of this method is examined by applying it to a large scale case study of water transfer from the Karoon river basin in southern Iran to the Rafsanjan plain in central Iran.     

Land Cover Change and Flood Risk in a Peri-Urban Environment of the Metropolitan Area of Rome (Italy)

Land cover change (LCC) is the most important factor in causing ecosystems services (ES) loss. In Mediterranean basins, coastal areas historically suffer from great anthropic pressure. These changes influence runoff, and municipal authorities often cannot estimate the impact of complex land cover transitions. In such context, the great urban and industrial development of the towns surrounding the city of Rome (Italy) represents a paradigmatic case study. In this paper, land cover evolution in a watershed located in a peri-urban environment has been studied in terms of LCC and the consequential flood risk. The information concerning land cover transformations was analyzed in following time scenarios: 1954, 1967 and 2018. The identification of occurred rainfall events, and the application of a combined hydrological and hydraulic modelling, allowed the estimation of flooded areas and volumes. The obtained results allowed to quantify the increase in the flood risk, that was more pronounced in the part of the selected area that has been more extensively interested by the soil sealing. The increase in the flood risk was larger in the hypothesis of a rainfall occurring when the soil is dry, like it can happen for the common case of summer precipitations.

     

Water Allocation in Transboundary River Basins under Water Scarcity: a Cooperative Bargaining Approach

Transboundary river basins are one of the main sources of fresh water which are facing water scarcity. When transboundary water is contested not only the allocation outcomes matter but also the allocation process should possess a certain desirable properties such as flexibility and sustainability. Therefore designing a mechanism that possesses these desirable characteristics and allocates the contested water resource is important as well. This article proposed a water allocation framework by combining the bankruptcy theory with asymmetric Nash bargaining solution concept for solving the water sharing problem in transboundary river basins under scarcity. Furthermore, the allocation framework was applied to the Nile river basin and to a hypothetical water scarce transboundary river basin. The results obtained were then compared with the allocation outcomes from classical bankruptcy allocation rules. The results showed that the proposed method can provide insights which could be useful for obtaining water allocation outcomes which are easier to implement and enforce under water scarce conditions.

     

改革中央水利国有资产管理体制的理论思考

改革水利行政事业性资产管理体制的原则是“中央、地方分级所有,水利部、流域机构分级监管,行政事业单位占有使用”。改革的思路是建立一个“权责明确,监管有力,配置灵活,有效使用”的管理体制,改革水利经营性资产管理体制与运行机制的思路是“构造运营主体,实现所有权与经营权相分离,引入竞争机制,实现运营主体产权多元化;强化约束激励机制,统筹兼顾各方利益”。流域控制性水利工程资产产权必须归流域机构,这是流域控制性资产的公益性质所决定的。     

Comparative Simulation of GIS-Based Rainwater Management Solutions

Rain Water Harvesting (RWH) as a solution for sustainable rainwater management is the focus of this research. To locate the potential sites for RWH, multi-criteria analysis following analytical hierarchy process using land-use/landcover, slope, drainage density, and runoff depth has been performed. By introducing continuous soil moisture accounting procedure in the globally used SCS-CN method, discrepancies in computed runoff values have been assessed. To appraise the usefulness of revised Soil Moisture Accounting (SMA) -enhanced SCS-CN models, a number of modifications have been compared. The models’ performance has been evaluated using R², Root Mean Square Error (RMSE), Nash Sutcliffe Efficiency (NSE), Percent BIAS (PBIAS) statistical indicators, and Rank Grading System (RGS) and the best has been selected to calculate the runoff depth for RWH potential zones. The resultant suitability map classifies Gurriala catchment into three suitability zones. 33.8% of the total area has been found as least suitable, comprised mainly of forest, residential land, and water bodies, while 46.8% and 19.4% of the area is recognized as moderately suitable and high suitable respectively. Selected suitable sites have been further classified into suitability zones for enhanced RWH structures and runoff volume contributed by each RWH structure has been computed. The total runoff potential of the area is 22.47 MCM that is enough to fulfill the water demands of suburban areas as a most inexpensive solution.

     

流域生态环境需水与缺水的快速评估（I）：理论

为识别生态环境缺水严重的区域和合理评价生态环境用水的配置效果,本文提出了一种新的流域生态环境需水与生态环境缺水快速评估方法。将流域的生态环境需水满足程度定义为,流域“实际生态环境用水”与流域在未受或少受人类活动干扰时的“自然状态条件下的生态环境用水”的接近程度。以土地利用资料为基础,运用层次分析法构建流域生态环境需水特征指标来表征流域生态环境用水的相对大小;借鉴水体生物快速评估法的思想,通过流域单元划分、参照单元选择、参照组构建、参照组匹配、观测值与期望值的比较计算等步骤,可以对不同级别流域的生态环境缺水问题进行深入分析,从而快速识别生态缺水严重区域、预测其生态缺水动态变化,并对生态环境用水配置效果进行评价。     

Risk Assessment for Ecological Planning of Arid Inland River Basins Under Hydrological and Management Uncertainties

The Shiyanghe river basin, an arid inland basin of northwest China, is taken as an example to analyze the risk for achieving the ecological planning objective in arid inland river basins under uncertainty conditions. Hydrology and management uncertainties that affect the accomplishment of ecological planning objective are analyzed quantitatively with the methods of Bayesian theory based Probabilistic model, scenario analysis and interval analysis. Bayesian probabilistic analysis method was used to analyze the hydrological uncertainties in the form of probability and interval distributions in planning period, while the scenario analysis method and interval method were used to analyze the managing uncertainties in the form of interval numbers. Instead of the ecological risk analysis, which for arid inland river basin, of studying the impact of environmental and human factor on ecological system, water resources and environment, we focused on analysing the possible impact of hydrological and management uncertainty factor on the ecological planning, and forecasting the degree of the completion under the uncertainty. Our study provided the probabilities of achieving ecological planning objective and the possible deviation of different scenarios. The more local water resources and higher level of local water resource utilization and management appeared to lead higher probability to achieve the ecological objective. This study can help environment and water resource managers and planner to formulate a rational planning for arid inland river basins under hydrological and management uncertainty.     

流域生态环境需水与缺水的快速评估(Ⅰ)：理论

为识别生态环境缺水严重的区域,合理评价生态环境用水的配置效果,本文提出了一种新的流域生态环境需水与生态环境缺水快速评估方法。将流域的生态环境需水满足程度定义为,流域"实际生态环境用水"与流域在未受或少受人类活动干扰时的"自然状态条件下的生态环境用水"的接近程度。以土地利用资料为基础,运用层次分析法构建流域生态环境需水特征指标来表征流域生态环境用水的相对大小;借鉴水体生物快速评估法的思想,通过流域单元划分、参照单元选择、参照组构建、参照组匹配、观测值与期望值的比较计算等步骤,可以对不同级别流域的生态环境缺水问题进行深入分析,从而快速识别生态环境缺水严重区域、预测其生态环境缺水动态变化,并对生态环境用水配置效果进行评价。     

国际泥沙计划案例研究综述

在全球变化等多种因素的影响下,许多流域的泥沙问题严重,泥沙管理的重要性日益突出。通过对联合国教科文组织国际泥沙计划所开展的案例研究进行综述,认识到自然地理特征、社会经济条件、水利工程建设对流域产沙、输沙和水资源利用有重要影响。土壤侵蚀加速、水库淤积、下游输沙量减少和生态平衡破坏是目前全球各大流域面临的主要问题。综合各项案例,研究泥沙管理技术,提出流域综合泥沙管理的策略,包括水库淤积管理、推移质泥沙管理、土地管理和水土保持等技术手段,以及法律、行政和组织措施。