Modeling of extreme freshwater outflow from the north-eastern Japanese river basins to western Pacific Ocean

This study demonstrates the importance of accurate extreme discharge input in hydrological and oceanographic combined modeling by introducing two extreme typhoon events. We investigated the effects of extreme freshwater outflow events from river mouths on sea surface salinity distribution (SSS) in the coastal zone of the north-eastern Japan. Previous studies have used observed discharge at the river mouth, as well as seasonally averaged inter-annual, annual, monthly or daily simulated data. Here, we reproduced the hourly peak discharge during two typhoon events for a targeted set of nine rivers and compared their impact on SSS in the coastal zone based on observed, climatological and simulated freshwater outflows in conjunction with verification of the results using satellite remote-sensing data. We created a set of hourly simulated freshwater outflow data from nine first-class Japanese river basins flowing to the western Pacific Ocean for the two targeted typhoon events (Chataan and Roke) and used it with the integrated hydrological (CDRMV3.1.1) and oceanographic (JCOPE-T) model, to compare the case using climatological mean monthly discharges as freshwater input from rivers with the case using our hydrological model simulated discharges. By using the CDRMV model optimized with the SCE-UA method, we successfully reproduced hindcasts for peak discharges of extreme typhoon events at the river mouths and could consider multiple river basin locations. Modeled SSS results were verified by comparison with Chlorophyll-a distribution, observed by satellite remote sensing. The projection of SSS in the coastal zone became more realistic than without including extreme freshwater outflow. These results suggest that our hydrological models with optimized model parameters calibrated to the Typhoon Roke and Chataan cases can be successfully used to predict runoff values from other extreme precipitation events with similar physical characteristics. Proper simulation of extreme typhoon events provides more realistic coastal SSS and may allow a different scenario analysis with various precipitation inputs for developing a nowcasting analysis in the future

Soil Erosion

In the first section of this book on soil erosion, an introduction to the soil erosion problem is presented. In the first part of the second section, rainfall erosivity is estimated on the basis of pluviograph records and cumulative rainfall depths by means of empirical equations and machine learning methods. In the second part of the second section, a physically-based, hydrodynamic, finite element model is described for the computation of surface runoff and channel flows. In the first part of the third section, the soil erosion risk is assessed in two different basins. In the second part of the third section, the soil erosion risk management in a basin is evaluated, and the delimitation of the areas requiring priority planning is achieved

Spatial and Long-Term Temporal Changes in Water Quality Dynamics of the Tonle Sap Ecosystem

Tonle Sap lake-river floodplain ecosystem (TSE) is one of the world’s most productive freshwater systems. Changes in hydrology, climate, population density, and land use influence water quality in this system. We investigated long term water quality dynamics (22 years) in space and time and identified potential changes in nutrient limitation based on nutrient ratios of inorganic nitrogen and phosphorus. Water quality was assessed at five sites highlighting the dynamics in wet and dry seasons. Predictors of water quality included watershed land use, climate, population, and water level. Most water quality parameters varied across TSE, except pH and nitrate that remained constant at all sites. In the last decade, there is a change in the chemical nutrient ratio suggesting that nitrogen may be the primary limiting nutrient across the system. Water quality was strongly affected by development in the watershed i.e., flooded forest loss, climatic variation, population growth, and change in water level. Seasonal variations of water quality constituents were driven by precipitation and hydrology, notably the Mekong’s distinct seasonal flood pulse

TIMBER HARVEST ADJACENCY ECONOMIES, HUNTING, SPECIES PROTECTION, AND OLD GROWTH VALUE: SEEKING THE OPTIMUM

Spatial forest management models recognize that nontimber benefits cat1 be influenced by the status of adjacent land. For instance, contiguous old growth provides habitat, aesthetic value, and environmental services. Conversely, edge areas provide forage and cover habitat for game and non-game wildlife. However, adjacency externalities are not limited to nontimber concerns. Larger harvest areas generate average cost savings as fixed harvesting costs are spread across greater acreage, a problem excluded from most literature on optimal harvesting. Hence, it is typical that economies and diseconomies of adjacency in harvesting occur simultaneously. This complicates the determination of optimal ecosystem management behavior, which recognizes timber, aesthetic, wildlife protection, and hunting values. This paper conceptually portrays economies of adjacency in competing objectives using multiple management strategies.Resource /Energy Economics and Policy,

Urban Runoff Control and Sponge City Construction

The rapid urbanization, sometimes lacking adequate planning and design, has led to worsening city syndrome situations, such as urban flooding, water pollution, heat island effects, and ecologic deterioration. Sponge city construction have become the new paradigm for a sustainable urban stormwater management strategy. Deviating from the traditional rapid draining approach, the new paradigm calls for the use of natural systems, such as soil and vegetation, as part of the urban runoff control strategy. It has become a widespread focus in urban water management research and practices globally. In this Special Issue reprint, there are 13 original scientific articles that address the different related urban runoff control issues. We are happy to see that all papers presented findings characterized as innovative and methodologically new. We hope that the readers can enjoy and learn deeply about urban runoff control and sponge city construction using the published material, and we hope that sharing of the researches results with the scientific community, policymakers and stakeholders can prompt the urban runoff control and sponge city construction globally

Improved water and land management in the Ethiopian highlands: its impact on downstream stakeholders dependent on the Blue Nile; Intermediate Results Dissemination Workshop February 5-6, 2009, Addis Ababa, Ethiopia

River basin management, Watershed management, Farming systems, Water balance, Reservoirs, Water supply, Irrigation requirements, Irrigation programs, Simulation models, Sedimentation, Rainfall-Runoff relationships, Erosion, Soil water, Water balance, Soil conservation, Institutions, Organizations, Policy, Water governance, International waters, Institutional and Behavioral Economics, Land Economics/Use, Resource /Energy Economics and Policy,

The Effect of Climate Change, Human Activity, and Water Management Interventions on Environmental and Socio-Economic Outcomes in the Mekong Delta Region

The Vietnam Mekong Delta (VMD) is the southernmost part of the Mekong River watershed basin and plays a critical role in Vietnam’s socio-economic and ecological wellbeing. Because of both climate change and anthropogenic activities, such as hydropower dam construction and overwhelming water extraction, the area has recently experienced severe droughts, changing rainfall patterns, and decreasing water resources, collectively heightening disaster risks. Understanding the interactions among these evolving factors is key to preserving resources in the VMD and similarly afflicted regions. Therefore, this dissertation included three objectives. The first objective was to estimate potential impacts of changes in the available water resources in the research area by predicting soil moisture and drought risk in the Mekong Delta using the Variable Infiltration Capacity (VIC) model. The second objective was to develop and validate an Artificial Neural Networks (ANNs) that would be able to predict soil moisture in the Mekong Delta. This process entailed using historical soil moisture data and comparing those data with the ANNs predicted model data. The third objective was to evaluate the willingness of the inhabitants of the VMD to engage in potential tradeoffs to avoid potential disaster risk in the region and to use this information to assist the Vietnamese government in developing environmental policies in the VMD. The VIC model showed that land cover change would have minimal impact on soil moisture in the area, that an increase in cropland would result in a decrease in soil moisture, and that there would be notable differences in soil moisture during the wet versus dry season. Also, the model showed that there would be severe drought in the period between the wet and dry season along the VMD’s western coastline. The ANNs model resulted in a high correlation between the historical data and the predicted soil moisture. In brief, both the VIC model and the ANN model have the ability to predict soil moisture. After the Vietnamese government introduced a flood management system, altering the natural flood pattern, VMD residents of both the area immediately downstream from the flood management structures and those who lived farther downstream were negatively affected socioeconomically. We conducted a survey of residents of the VMD and found that residents were willing to trade off some shortterm benefits for long-term stability, but the residents farthest downstream were more willing to accept tradeoffs than those residing immediately below the flood management system, as those farther downstream were more negatively affected by the new flood plan

Climate Change and Environmental Sustainability-Volume 4

Anthropogenic activities are significant drivers of climate change and environmental degradation. Such activities are particularly influential in the context of the land system that is an important medium connecting earth surface, atmospheric dynamics, ecological systems, and human activities. Assessment of land use land cover changes and associated environmental, economic, and social consequences is essential to provide references for enhancing climate resilience and improving environmental sustainability. On the one hand, this book touches on various environmental topics, including soil erosion, crop yield, bioclimatic variation, carbon emission, natural vegetation dynamics, ecosystem and biodiversity degradation, and habitat quality caused by both climate change and earth surface modifications. On the other hand, it explores a series of socioeconomic facts, such as education equity, population migration, economic growth, sustainable development, and urban structure transformation, along with urbanization. The results of this book are of significance in terms of revealing the impact of land use land cover changes and generating policy recommendations for land management. More broadly, this book is important for understanding the interrelationships among life on land, good health and wellbeing, quality education, climate actions, economic growth, sustainable cities and communities, and responsible consumption and production according to the United Nations Sustainable Development Goals. We expect the book to benefit decision makers, practitioners, and researchers in different fields, such as climate governance, crop science and agricultural engineering, forest ecosystem, land management, urban planning and design, urban governance, and institutional operation.Prof. Bao-Jie He acknowledges the Project NO. 2021CDJQY-004 supported by the Fundamental Research Funds for the Central Universities and the Project NO. 2022ZA01 supported by the State Key Laboratory of Subtropical Building Science, South China University of Technology, China. We appreciate the assistance of Mr. Lifeng Xiong, Mr. Wei Wang, Ms. Xueke Chen, and Ms. Anxian Chen at School of Architecture and Urban Planning, Chongqing University, China

Strategic Analyses of the National River Linking Project (NRLP) of India, Series 1. India’s water future: scenarios and issues

River basinsEnvironmental flowsDevelopment projectsWater requirementsIrrigated farmingWater demandFood demandGroundwater irrigationIrrigation efficiencyWater harvestingSupplemental irrigationWater productivityWater conservationDrip irrigationSprinkler irrigationRainfed farmingAgricultural policy