Along with the sequent completion of Manwan and Dachaoshan Dam, the river continuum of the middle and lower reaches of the Lancang River was separated into three types of segments: reservoir, below-dam segment and downstream flowing segment. The long-term series of water quality and river flow data over 20 years were analyzed in order to study the impact of dam construction and operation on water quality and water self-purification capacity of these different river segments. From pre-dam period to the first 7 years after Manwan Dam had been accomplished, the water quality of Manwan Reservoir became worse due to the accumulation of pollutants, and then to the next 5 years the water quality became better in virtue of the water self-purification of the reservoir. The cooperative operation of Manwan and Dachaoshan Dam had cumulatively positive impacts on water quality of their below-dam segment but no impacts on that of downstream flowing segment. From pre-dam period to the first 7 years after the closure of Manwan Dam, the water self-purification capacity of Xiaowan–Manwan segment for BOD5, CODMn and NH3–N decreased. Also, the water self-purification capacity of Manwan–Dachaoshan segment for BOD5 and CODMn decreased but for NH3–N increased. However, the water self-purification capacity of Jinghong–Ganlanba segment changed contrary to Manwan–Dachaoshan segment. In general, the construction of Manwan Dam negatively affected the water self-purification capacity of reservoir and below-dam segment but impose little impact on that of downstream flowing segment. This study suggested that it is necessary to pay attention to the effect of complicated temporal and spatial characteristics of dam on aquatic ecosystem.

Impact of Dam Construction on Water Quality and Water Self-Purification Capacity of the Lancang River, China

The flood risk management plan challenges both water engineers and spatial planners. It calls for a new mode of governance for flood risk management. This contribution analyses how this mode of governance distinguishes from prevalent approaches. Spatial planning and water management in Europe are explored in terms of their actor relation, their institutional context, and their approach to the object. These three characteristics of the modes of governance are compared with the governance requirements that flood risk management demands. It is concluded that the governance of flood risk management in Europe should strike a balance between comprehensive and hierarchical planning on the one hand, and interactive planning on the other hand, leading to a spatial water governance.

The flood risk management plan: towards spatial water governance

PREFACE. 1 INTRODUCTION. 1.1 Principles of Water-Quality Control. 1.2 Sources of Water Pollution. 1.2.1 Point Sources. 1.2.2 Nonpoint Sources. 1.3 Laws and Regulations. 1.3.1 Clean Water Act. 1.3.2 Safe Drinking Water Act. 1.4 Strategy for Water-Quality Management. 1.4.1 Use-Attainability Analysis. 1.4.2 Total Maximum Daily Load Process. Summary. Problems. 2 WATER-QUALITY STANDARDS. 2.1 Introduction. 2.2 Measures of Water Quality. 2.2.1 Physical Measures. 2.2.2 Chemical Measures. 2.2.3 Biological Measures. 2.3 U.S. Surface-Water Standards. 2.3.1 Designated Beneficial Uses. 2.3.2 Water-Quality Criteria. 2.3.3 Antidegradation Policy. 2.3.4 General Water-Quality Management Practices. 2.4 U.S. Ground-Water Standards. 2.5 Background Water Quality. 2.6 Computer Codes. Summary. Problems. 3 FATE AND TRANSPORT IN AQUATIC SYSTEMS. 3.1 Mixing of Dissolved Constituents. 3.2 Properties of the Diffusion Equation. 3.2.1 Fundamental Solution in One Dimension. 3.2.2 Principle of Superposition. 3.2.3 Solutions in Higher Dimensions. 3.2.4 Moment Property of the Diffusion Equation. 3.2.5 Nondimensional Form. 3.3 Transport of Suspended Particles. Summary. Problems. 4 RIVERS AND STREAMS. 4.1 Introduction. 4.2 Transport Processes. 4.2.1 Initial Mixing. 4.2.2 Longitudinal Dispersion. 4.3 Spills. 4.3.1 Governing Equation. 4.3.2 Fate of Volatile Organic Compounds in Streams. 4.4 Continuous Discharges. 4.4.1 Oxygen Demand of Wastewater. 4.4.2 Reaeration. 4.4.3 Streeter-Phelps Model. 4.4.4 Other Considerations. 4.5 Restoration and Management. 4.5.1 Nonstructural Techniques. 4.5.2 Structural Techniques. 4.6 Computer Codes. Summary. Problems. 5 LAKES AND RESERVOIRS. 5.1 Introduction. 5.2 Natural Processes. 5.2.1 Flow and Dispersion. 5.2.2 Light Penetration. 5.2.3 Sedimentation. 5.2.4 Eutrophication and Nutrient Recycling. 5.2.5 Thermal Stratification. 5.3 Water-Quality Models. 5.3.1 Zero-Dimensional (Completely Mixed) Model. 5.3.2 One-Dimensional (Vertical) Models. 5.3.3 Two-Dimensional Models. 5.4 Restoration and Management. 5.4.1 Control of Eutrophication. 5.4.2 Control of Dissolved-Oxygen Levels. 5.4.3 Control of Toxic Contaminants. 5.4.4 Control of Acidity. 5.4.5 Control of Aquatic Plants. 5.4.6 Attainability of Lake Uses. 5.5 Computer Codes. Summary. Problems. 6 WETLANDS. 6.1 Introduction. 6.2 Natural Wetlands. 6.2.1 Marshes. 6.2.2 Swamps. 6.2.3 Bogs. 6.2.4 Fens. 6.3 Delineation of Wetlands. 6.3.1 Vegetation. 6.3.2 Soils. 6.3.3 Hydrology. 6.4 Wetland Hydrology. 6.4.1 Net Surface-Water Inflow. 6.4.2 Net Ground-Water Inflow. 6.4.3 Evapotranspiration. 6.5 Case Study: The Everglades and Big Cypress Swamp. 6.6 Constructed Treatment Wetlands. 6.6.1 Surface-Flow Wetlands. 6.6.2 Subsurface-Flow Wetlands. 6.6.3 Wetland Regulations in the United States. 6.6.4 Basic Principles for Wetland Restoration and Creation. 6.6.5 Design of Constructed Treatment Wetlands. 6.6.6 Wetlands for Treating Roadway Runoff. Summary. Problems. 7 GROUND WATER. 7.1 Introduction. 7.2 Natural Ground-Water Quality. 7.3 Contaminant Sources. 7.3.1 Septic Tanks. 7.3.2 Leaking Underground Storage Tanks. 7.3.3 Land Application of Wastewater. 7.3.4 Irrigation and Irrigation Return Flow. 7.3.5 Solid-Waste Disposal Sites. 7.3.6 Waste-Disposal Injection Wells. 7.3.7 Agricultural Operations. 7.4 Fate and Transport Models. 7.4.1 Instantaneous Point Source. 7.4.2 Continuous Point Source. 7.4.3 Continuous Plane Source. 7.5 Transport Processes. 7.6 Fate Processes. 7.6.1 Sorption. 7.6.2 First-Order Decay. 7.6.3 Combined Processes. 7.7 Nonaqueous-Phase Liquids. 7.8 Remediation of Subsurface Contamination. 7.8.1 Remediation Goals. 7.8.2 Site Investigation. 7.8.3 Remediation Strategies. 7.9 Computer Models. Summary. Problems. 8 OCEANS AND ESTUARIES. 8.1 Introduction. 8.2 Ocean-Outfall Discharges. 8.2.1 Near-Field Mixing. 8.2.2 Far-Field Mixing. 8.3 Water-Quality Control in Estuaries. 8.3.1 Classification of Estuaries. 8.3.2 Physical Conditions. 8.3.3 Chemical Conditions. 8.3.4 Biological Conditions. 8.3.5 Use-Attainability Evaluations. 8.4 Computer Models. Summary. Problems. 9 WATERSHEDS. 9.1 Introduction. 9.2 Source-Water Protection. 9.3 Watershed-Generated Pollutant Loads. 9.4 Urban Watersheds. 9.4.1 Sources of Pollution. 9.4.2 Fate and Transport Processes. 9.4.3 Best Management Practices. 9.5 Agricultural Watersheds. 9.5.1 Sources of Pollution. 9.5.2 Fate and Transport Processes. 9.5.3 Best Management Practices. 9.6 Airsheds. 9.6.1 Nitrogen Compounds. 9.6.2 Mercury. 9.6.3 Other Metals. 9.6.4 Pesticides. 9.6.5 Combustion Emissions. 9.7 Computer Models. Summary. Problems. APPENDIX A UNITS AND CONVERSION FACTORS. A.1 Units. A.2 Conversion Factors. APPENDIX B FLUID PROPERTIES. B.1 Water. B.2 Organic Compounds Found in Water. B.3 Air at Standard Atmospheric Pressure. APPENDIX C U.S.WATER-QUALITY STANDARDS. C.1 Water-Quality Criteria for Surface Waters. C.2 Water-Quality Criteria for Drinking Water. C.3 Priority Pollutants. APPENDIX D STATISTICAL TABLES. D.1 Areas Under the Standard Normal Curve. APPENDIX E SPECIAL FUNCTIONS. E.1 Error Function. E.2 Bessel Functions. E.2.1 Definition. E.2.2 Evaluation of Bessel Functions. E.3 Gamma Function. APPENDIX F PIPE SPECIFICATIONS. F.1 PVC Pipe. F.2 Ductile Iron Pipe. F.3 Concrete Pipe. REFERENCES. INDEX.

Water-Quality Engineering in Natural Systems

The computationally difficult problem of the optimal placement of excitations and sensors to maximize the observed measurements is studied within the framework of combinatorial optimization, and is solved numerically using a variation of the simulated annealing heuristic algorithm. Results of numerical experiments including a square plate and a 960 degrees-of-freedom Control of Flexible Structure (COFS) truss structure, are presented. Though the algorithm produces suboptimal solutions, its generality and simplicity allow the treatment of complex dynamical systems which would otherwise be difficult to handle.

Optimal placement of excitations and sensors for verification of large dynamical systems

This review paper critically examines one of the most popular flood hydrograph modelling techniques for ungauged basins, the synthetic unit hydrograph (SUH), and its recent developments and advances. For this purpose, the SUH models were first grouped into four main classes, as follows: (a) traditional or empirical models; (b) conceptual models; (c) probabilistic models; and (d) geomorphological models. It was found that the geomorphological class is the most useful and interesting, since it is able to employ topographic information, so limiting the role of the calibration parameters. This review is expected to be helpful to hydrologists, water managers and decision-makers searching for models to study the flood hydrograph, modelling techniques and related processes in ungauged basins. It was completed as the International Association of Hydrological Sciences (IAHS) Decade (2003–2012) on predictions in ungauged basins (PUB), drew to a close. Editor D. Koutsoyiannis; Associate editor S. GrimaldiCit...

https://www.tandfonline.com/doi/pdf/10.1080/02626667.2013.870664

A review of the synthetic unit hydrograph: from the empirical UH to advanced geomorphological methods

The conversion of rainfall to surface runoff in urbanized watersheds is represented by a model composed of three main elements. The first element receives the total rainfall hyetograph as input and produces two rainfall excess hyetographs as output. These are used as inputs to the other two elements which are in parallel. The two elements, representing the impervious and the pervious portions of the watershed, were taken to be composed of cascades of linear reservoirs. The elements produce as their outputs two hydrographs that are added to produce the direct surface runoff hydrograph of the watershed. The first element of the model is nonlinear but the other two are linear. The model, viewed as one unit converting total rainfall to runoff, is thus nonlinear. Data from a semi-arid urban watershed in Arizona were used to demonstrate the use of the model.

Parallel Cascades Model for Urban Watersheds

For people who are involved in the applied aspects of hydrology, it is refreshing to find a textbook that begins with a meaningful disclaimer, albeit in fine print on the back side of the frontispiece:

“The present book and the accompanying software have been written according to the latest techniques in scientific hydrology. However, hydrology is at best an inexact science. A good book and a good computer software by themselves do not guarantee accurate or even realistic predictions. Acceptable results in the applications of hydrologic methods to engineering and environmental problems depend to a greater extend (sic) on the skills, logical assumptions, and practical experience of the user, and on the quantity and quality of long-term hydrologic data available. Neither the author nor the publisher assumes any responsibility or any liability, explicitly or implicitly, on the results or the consequences of using the information contained in this book or its accompanying software.”

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/97EO10318

Hydrology for Engineers, Geologists, and Environmental Professionals

Potentially useful market solutions to minimize flood damageinclude purchase of space in existing reservoirs, purchase offlooding rights from farmers and other land owners, and privately produced levees to protect housing and commercialdevelopment. These private solutions are often limited by risk considerations, free riders, and the transactions costsassociated with large groups, necessitating public sector provision of flood control measures. Thus, most market participants will be public entities.

Integrating Market Solutions into Government Flood Control Policies

Model studies and analysis of oceanographic and littoral drift data were undertaken to advise Howe India (Private) Ltd. on littoral drift, siltation and shore erosion problems to be encountered during and after the construction of Visakhapatnam Outer Harbor Project. Distorted fixed-bed and movable-bed models with a horizontal scale of 1:300 and a vertical scale of 1:80 were calibrated to reproduce the integrated net effect of an average southwest and northeast monsoon season. Experiments were conducted to assess and predict seasonal changes resulting from the construction of the system of breakwaters under normal and extreme conditions. Recommendations were made concerning breakwater and sand trap location, shore protection, dredging and disposal of dredged material.

/pdf/field-and-model-studies-for-visakhapatnam-harbor-31gn0la586.pdf

Simon Ince

Papers

Parallel Cascades Model for Urban Watersheds

Hydrology for Engineers, Geologists, and Environmental Professionals

Integrating Market Solutions into Government Flood Control Policies

Field and Model Studies for Visakhapatnam Harbor

Sediment-Freshwater Interaction