1 Opening Speech Time: 08:45 - 09:00 President’S Speech: Jian Guo Zhou, 10 Min Dean’S Speech: Baoshan Cui, 5 Min

Home , Caohai Lake, East Lake (Wuhan), Tangxun Lake

Sponsored by

National Key R&D Program of China （2018YFC1406400, 2016YFC0500402, 2017YFC0506603, 2018YFC0407403）

Key Lab of Water and Sediment Science of the Ministry of Education （IAHR）

International Association for Hydro-Environment Engineering and Research

Scientific Committee

Name School Country

John Bridgeman The University of Bradford U.K.

Stuart Bunn Griffith University Australia John Cater The University of Auckland New Zealand

Muk Chen Ong University of Stavanger Norway Taiwan, Jianzhong Chen Fooyin University China Carlo Gualtieri University of Naples Italy China Institute of Water Resources and Wei Huang China Hydropower Research Magnus Larson Lund University Sweden

Yiping Li Hohai University China

Pengzhi Lin Sichuan University China China Institute of Water Resources and Shu Liu China Hydropower Research William Nardin The University of Maryland U.S.A.

Ling Qian Manchester Metropolitan University U.K.

Benedict Rogers The University of Manchester U.K.

Xinshan Song Donghua University China

Marcel Stive Delft University of Technology Netherlands

Guangzhi Sun Edith Cowan University Australia

Xuelin Tang Chinese Agricultural University China

Roger Wang Rutgers University U.S.A.

Zheng Bing Wang Delft University of Technology Netherlands

Yujun Yi Beijing Normal University China

Xiao Yu University of Florida U.S.A.

Zhonglong Zhang Portland State University U.S.A.

Conference Committee

Chair: Jian Guo Zhou, Manchester Metropolitan University Co-Chairs: Baoshan Cui, Beijing Normal University Alistair G.L. Borthwick, The University of Edinburgh Jianmin Zhang, Sichuan University Jinhai Zheng, Hohai University

Organizing Committee

Chair: Haifei Liu Co-Chairs: Tao Sun Wei Yang Dongdong Shao Xiaohua Yang Yujun Yi Jing Qi

Programme

Date Time Content Venue

Conference Center July 7th 14:00-21:00 Registration Xijiao Hotel

08:45-09:00 Opening Speech 3rd Floor Gingko Hall 09:00-10:20 Keynote Speech 1&2 Conference Center

10:20-10:50 Group Photo 3rd Floor 10:50-12:10 Keynote Speech 3&4 Gingko Hall July 8th Conference Center 2nd Floor 12:10-14:00 Lunch Building No.5

14:00-15:20 Keynote Speech 5&6 3rd Floor Gingko Hall 15:35-16:55 Keynote Speech 7&8 Conference Center

1st Floor 18:00-20:00 Banquet Building No.5 Theme Session 1: 09:00-10:30 nd Hydraulic Modelling Ⅰ 2 Floor Conference Room 6 Theme Session 2: 10:45-12:15 Conference Center Hydro-environment Modelling Ⅰ 2nd Floor July 9th 12:15-14:00 Lunch Building No.5 Theme Session 3: 14:00-15:30 nd Hydro-ecology Modelling 2 Floor Conference Room 6 Theme Session 4: 15:45-17:15 Conference Center Experiment and Software Theme Session 5: 09:00-10:30 nd Hydraulic Modelling Ⅱ 2 Floor Conference Room 6 Theme Session 6: 10:45-12:15 Conference Center Hydro-environment Modelling Ⅱ 2nd Floor July 10th 12:15-14:00 Lunch Building No.5 Theme Session 7: 14:00-15:30 nd Water Management Modelling 2 Floor Conference Room 6 Theme Session 8: 15:45-17:15 Conference Center Marine Ranching Study

I. Day 1 (Monday, July 8th)

1 Opening Speech Time: 08:45 - 09:00 President’s Speech: Jian Guo Zhou, 10 min Dean’s Speech: Baoshan Cui, 5 min

2 Keynote Speech Time: 09:00-16:55 Chair: Jian Guo Zhou (Manchester Metropolitan University)

Time Topic Speaker

Uncertain Power from Shallow Alistair G.L. Borthwick 09:00-09:40 Water The University of Edinburgh, U.K.

Zheng Bing Wang Modelling Response of Tidal 09:40-10:20 Delft University of Technology, Basins to Relative Sea-level Rise Netherlands

10:20-10:50 Group Photo and Tea Break

Physical-biological Process David Hamilton 10:50-11:30 Coupling to Improve Simulations Griffith University, Australia of Cyanobacteria Blooms

From River to Reservoir and Zhenyao Shen 11:30-12:10 Estuary: Case Studies for Water Beijing Normal University, China Quality Modelling in China

12:10-14:00 Lunch

Time Topic Speaker (School, Country)

Sustainable Marine Environment Jun Sasaki 14:00-14:40 and Coastal Disaster Mitigation in The University of Tokyo, Japan Tokyo Bay

Paul Craig The Development History of 14:40-15:20 Dynamic Solutions-International, EFDC LLC, U.S. A

15:20-15:35 Tea Break

Mixing in Environmental Flows: Carlo Gualtieri 15:35-16:15 Theory, Field Measurements, University of Naples Federico II, Physical and Numerical Modelling Italy

Mechanisms and Numerical Tao Sun 16:15-16:55 Simulation of Eco-hydrological Beijing Normal University, China Processes in Coastal Ecosystems

3 Banquet Time: 18:00 - 20:00 Venue: 1st Floor, Building No.5

II. Day 2 (Tuesday, July 9th)

1 Session 1: Hydraulic Modelling Ⅰ

Time: 09:00 - 10:30 Chair: Zheng Bing Wang (Delft University of Technology, Netherlands) Page: P15-P27

Time Topic Speaker

Evaluating the Influence of Slope Xiangming Cao 09:00-09:15 Limiters on Wave Simulation in a Hohai University Non-Hydrostatic Model

Investigations into Assimilating Lei Ren 09:15-09:30 High Frequency Radar Data for a Sun Yat-sen University Coastal Water Body

Python-based Graphical User Elysia Barker Interface for a Lattice Boltzmann 09:30-09:45 Manchester Metropolitan Model Solving the Shallow Water University Equations

Research on Morphological Bixuan Dong 09:45-10:00 Characteristics of Rip Current in Hohai Uinversity Dadonghai, Sanya

Churui Wan Performance Prediction of Ice- 10:00-10:15 Marine Design & Research Classed Propeller Institute of China Shanghai

Parametric Sensitivity Studies on Obai Kargbo 10:15-10:30 Sloshing of a Layered Fluid Hohai Uinversity

10:30-10:45 Tea Break

2 Session 2: Hydro-environment Modelling I

Time: 10:45 - 12:15 Chair: Carlo Gualtieri (University of Naples, Italy) Page: P28-P37

Time Topic Speaker

Effects of River Mouth Dongxue Li 10:45-11:00 Progradation on the Evolution of Beijing Normal University River Longitudinal Profile

Application of MIKESHE Model in Water Environmental Yutong Li 11:00-11:15 Management for Anning River Beijing Normal University Basin

Hydrologic Response to Land Use Sameh Adib Abou Rafee 11:15-11:30 Changes in the Upper Paraná River Lund University Basin

Study on Ecological Water Jinglan Qin 11:30-11:45 Requirement of Hongze Lake for Beijing Normal University Bird Habitat Protect

Wind Effects on Hydrodynamics and Implications for Ecology in a Xuemei Liu 11:45-12:00 Hydraulically Dominated Shallow Chinese Academy of Sciences Lake System: Chagan Lake

Study on Eco-water Requirement Xintian Qiu 12:00-12:15 Accounting Method Based on Beijing Normal University Regime Shifts of Shallow Lakes

12:15-14:00 Lunch

3 Session 3: Hydro-ecology Modelling

Time: 14:00 – 15:30 Chair: Guangzhi Sun (Edith Cowan University, Australia) Page: P38-P51

Time Topic Speaker

Analysis of Ecological Hydrological Variation in the Yingshan Sun 14:00-14:15 Upstream of Baiyangdian Basin University of Jinan Based on Iha-Rva Numerical Investigation on Characteristics of Vortices at Cheng Zeng 14:15-14:30 Equal-Width Open-Channel Hohai University Confluences Hydrological Processes Governing the Ecological Degradation of Yuexin Zheng 14:30-14:45 Isolated Wetlands in Nenjiang Chinese Academy of Sciences River Basin Impact of Three Gorges Reservoir on Spawning Activity and Eco- Wenxian Guo 14:45-15:00 hydrologic Conditions of Four North China University of Water Major Chinese Carps in the Middle Resources and Electric Power of Yangtze River, China Quantitative Assessment on Yanfeng Wu 15:00-15:15 Watershed-Scale Hydrological Chinese Academy of Sciences Services of Wetlands

Response of Carbon Emission to Xiaomin Yuan 15:15-15:30 Fluctuation of Water Level in a Beijing Normal University Typical Shallow Wetland

15:30-15:45 Tea Break

4 Session 4: Experiment and Software

Time: 15:45 - 17:15 Chair: Dongdong Shao (Beijing Normal University, China) Page: P52-P63

Time Topic Speaker

Nanoparticle Impregnated Beads for In-Situ Removal of Nitrate Guangzhi Sun 15:45-16:00 from Contaminated Groundwater: Edith Cowan University Experimental Study and Mathematical Modelling Impact of Structures of Different Scale on Heat Transfer and Yuan Gao 16:00-16:15 Performance of Proton Exchange Tongji University Membrane Fuel Cells Investigation on Computing Method of Martian Dust Fluid Tianxiang Ding 16:15-16:30 based on the Energy Dissipation Harbin Institute of Technology Method

Wake Characteristics and Near- Dongdong Shao 16:30-16:45 field Mass Transport Processes Beijing Normal University through a Fishing Net Panel

CFD Investigations of Transient Cavitation Flows Based on Xiangyu Duan 16:45-17:00 Weakly-Compressible Model in China Agricultural University Pipeline

Distribution, Source and Tendency Xuan Chang 17:00-17:15 of Fe, Mn and Trace Metals in Beijing Normal University Urban Environmental Media

III. Day 3 (Wednesday, July 10th)

1 Session 5: Hydraulic Modelling II

Time: 09:00 - 10:30 Chair: Yong Peng (Sichuan University, China) Page: P64-P75

Time Topic Speaker

Effects of Obstacles on Lid-Driven Andrew Cunningham 9:00-9:15 Cavity Flows Using the Lattice- Manchester Metropolitan Boltzmann Method University

Parallel Lattice Boltzmann Method Zhiming Ru 9:15-9:30 for Shallow Water Equations on Beijing Normal University Quadtree Grids

A Method for Defining the Scope Kai Tian 9:30-9:45 of River-Lake Transition Zone Beijing Normal University Based on Velocity Gradient

Uncertainty and Sensitivity Yuanyuan Shi 9:45-10:00 Analysis of Phosphorus Model Hohai University Parameters in Large Shallow Lakes

Uncertainty of Runoff Time Series Yan Ye 10:00-10:15 at Multi-temporal Scales Southwest University

Simulation of Hydraulic Yunsong Cui 10:15-10:30 infrastructures in 2D High- Hohai University Resolution Urban Flood Model

10:30-10:45 Tea Break

2 Session 6: Hydro-environment Modelling II

Time: 10:45 - 12:15 Chair: Yujun Yi (Beijing Normal University, China) Page: P76-P86

Time Topic Speaker

A Study of Minimum Ecological Dan Liu 10:45-11:00 Water Level of Lake Baiyangdian, Beijing Normal University North of China

A 1D-2D Coupled Lattice Hongda Wang 11:00-11:15 Boltzmann model for Shallow University of California, Davis Water Flows

Analysis of Water Quality Scenario Di Liu 11:15-11:30 Simulation in the Yellow River in Beijing University of Civil Ningxia Section Based on EFDC Engineering and Architecture

Effects of Dam Regulation on the Hydrological Alteration and Mawusi Amenuvor 11:30-11:45 Morphological Evolution of the Beijing Normal University Volta River Delta Numerical Study of Hydrodynamics and Water Quality Wei Huang 11:45-12:00 in Qinhuangdao Coastal Waters, China Institute of Water Resources China—A Well-known Region for and Hydropower Research Its Bathing Beaches Temporal Changes of Baseflow Xiaojing Ma 12:00-12:15 and Its Implication for Beijing Normal University Environmental Flow

12:15-14:00 Lunch

3 Session 7: Water Management Modelling

Time: 14:00 – 15:30 Chair: Yiping Li (Hohai University, China) Page: P87-P95=6

Time Topic Speaker

Min Li Urban Fluvial Flood Modelling 14:00-14:15 China Institue of Water Resources Study and Hydropower Research

Experimental Investigation of Air Chun Hoi Chiu 14:15-14:30 Entrainment in a Submerged The Hong Kong University of Plunging Dropshaft Science and Technology

Numerical Study of Environmental Chenguang Xiang Characteristics and Ecological 14:30-14:45 China Institue of Water Resources Water Supplement of Caohai Lake and Hydropower Research in Guizhou Province

Study on Locating Warning Hongwei Ding 14:45-15:00 Stations for Drinking Water Hohai University Sources Safety at Tidal Reaches

Evaluation of Water Resources Carrying Capacity in the Yangtze Qirui Xue 15:00-15:15 River Delta Region Based on Beijing Normal University Factor Index Method Assessing the Impact of the Three Hongxiang Wang Gorges Reservoir on Eco- 15:15-15:30 North China University of Water hydrological Regimes in the Resources and Electric Power Dongting Lake, China

15:30-15:45 Tea Break

4 Session 8: Marine Ranching Study

Time: 15:45 - 17:15 Chair: Tao Sun (Beijing Normal University, China) Page: P97-P105

Time Topic Speaker

Application of Stable Isotope Shanshan Ge 15:45-16:00 Technology in Modern Marine Marine Biology Institute of Ranching Shandong Province

Numerical Analysis of the Flows Gangqin Tu 16:00-16:15 around Fishing Plane Nets Using Beijing Normal University Lattice Boltzmann Methods Hydrodynamic Driving Mechanism and Process Qianzhao Sun 16:15-16:30 Simulation of Typical Beijing Normal University Biocompatible Habitat Pattern Changes in Estuary Parameterisation and Application Yanyu Li 16:30-16:45 of Dynamic Energy Budget Model Nankai University to Hexagrammos Otakii Modeling the Spatial Distribution of Reef Fish Populations around an Yue Zhang 16:45-17:00 Artificial Reef-field：Based on a Beijing Normal University Trade-off between Foraging Success and Predation Risk The Changing Characteristics and Ziyue Zhang 17:00-17:15 Driving Factors of Marine Fishery Beijing Normal University Resources in China

IV. Day 4 (Thursday, July 11th) Day trip: please contact the reception for more information.

Abstracts

Session 1: Hydraulic Modelling Ⅰ

Evaluating the Influence of Slope Limiters on Wave Simulation in a Non-Hydrostatic Model

Xiangming Cao1,*, Jinhai Zheng1, Jian Shi1, and Chi Zhang1 1 College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing 210024, China * Correspondence: Xiangming Cao, [email protected]

Keywords: slope limiter; wave simulation; numerical dissipation; non-hydrostatic model

1. Introduction

In the context of high efficiency wave models, the non-hydrostatic model has experienced rapid advances and has been tested for a diversity of coastal/ocean processes. However, when dealing with wave breaking, the non-hydrostatic term is treated differently in different models. In the benchmark of SWASH using a finite difference method, Smit et al. described the need to introduce the hybrid effect of turning off non-hydrostatic corrections, unless vertical grid resolution is increased significantly [1]. On the contrary, for NHWAVE based on a Godunov-type finite volume method, handling wave breaking does not require either adoption of a hybrid model strategy or an increase of vertical resolution [2]. It has been noted that the numerical dissipation induced by the slope limiters is important part of the total energy dissipation, and may even be dominant [3]. In this paper, we look into the impact of slope limiters on wave propagation in a non-hydrostatic model.

2. Methodology

Performances of the three slope limiters implemented in NHWAVE are examined in numerical experiments in which simulations of a solitary wave propagation are carried out. They are used to study the influence of slope limiters on phase speed and the dissipation characteristics of different slope limiters. The slope limiter results are compared with the solitary wave theory.

3. Results and Discussion

Table 1 lists the percentage changes between theoretical wave height and the wave height at 100s for different grid sizes with different slope limiters. The percentage listed in the table are calculated by (H1-H2)/H1, H1 denotes the theoretical wave height, H2 denotes the wave height at t=100s. The negative sign in the table indicates that the simulated wave height is higher than the theoretical value.

The model accuracy is affected by both the choice of limiters and the grid size. The minmod limiter is the most dissipative, which leads to a lower surface elevation and a smaller wave speed. It should be noted that even when the grid size reaches 0.02m, the damping rate after 100s remains 16.60%, which is still much higher than the others. The van Leer limiter 16

is the most stable for almost all the cases, except for the grid size 0.5 case. In this case, the van Leer limiter is dissipative with an uplift of the surface in the wave tail. However, for superbee limiter, in the coarse grid case, it leads to a higher surface elevation, which can be caused by its compressive character. With the refinement of the grid, the van Leer and superbee results reach the same stable state. With the unsmooth characteristic of the minmod limiter, overly refined grids may make the numerical simulation too time consuming, which is not suitable for engineering applications.

4. Conclusions

A good prediction of the solitary wave propagation is the combination of grid accuracy and grid convergence. The refinement of grids improves the grid accuracy for all slope limiters. The grid size 0.05m was proved accurate when comparing with wave theory for all slope limiters. However, the minmod limiter and the superbee limiter may not converge to the theoretical steady profile in the numerical simulation with grid size 0.05m. For the dissipative minmod limiter, the grid size needs to be finer in order to eliminate the numerical dissipation. For the anti-dissipative superbee limiter, the grids need to be coarser in order to achieve accurate wave height and avoid extra oscillations.

5. Acknowledgement

This work was supported by the National Natural Science Foundation of China (41706087, 51879096), the National Science Foundation for Distinguished Young Scholars (51425901), the Natural Science Foundation of Jiangsu Province (Grant No. BK20170867, BK20161509), Marine Science and Technology Innovation Project of Jiangsu Province (HY2018-15), the Fundamental Research Funds for the Central Universities(2017B2151, 2018B653X14), Postgraduate Research & Practice Innovation Program of Jiangsu Province(KYCX18_0613).

References

1. Shi, J., Shi, F., Kirby, J. T., Ma, G., Wu, G., Tong, C., Zheng, J., 2015.Pressure decimation and interpolation (pdi) method for a baroclinic non-hydrostatic model. Ocean Modelling 96, 265-279.

2. Ma, G., Shi, F., Kirby, J. T., 2012. Shock-capturing non-hydrostatic model for fully dispersive surface wave processes. Ocean Modelling 43-44, 22-35.

3. Kirby, J. T., 2016. Boussinesq models and their application to coastal processes across a wide range of scales. Journal of Waterway, Port, Coastal, and Ocean Engineering 142 (6), 03116005.

Investigations into Assimilating High Frequency Radar Data for a Coastal Water Body

Lei Ren1,2,*, Michael Hartnett3 1 School Marine Engineering and Technology, Sun Yat-sen University, Zhuhai 519000, China 2 Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China 3 School of Engineering and Informatics, National University of Ireland, Galway, Ireland * Correspondence: Lei Ren, [email protected]

Keywords: surface currents, data assimilation, radars, forecasting, coastal water

1. Introduction

Accurate forecasting of surface currents in coastal areas is of great importance for operations such as search and rescue, fishing, and pollution monitoring. Observations, scaled physical modelling, and numerical modelling are commonly used methods to study dynamic processes of coastal waters. Each of these provides meaningful information to analyze dynamic processes of relevant phenomena. However, each approach has its own constraints and shortcomings. Observations based on remote sensing are a desirable way to obtain data of real states, but they are usually expensive. Moreover, observation biases from observers or measurement tools can reduce the reliability of recorded data. Scaled physical experimentation is a useful way to investigate variations of dynamic processes, but such experiments are usually time-consuming and expensive to perform. In addition, limitations exist when extrapolating data obtained from a scaled model to a prototype, such as scaling, friction, and viscosity; experimental errors are also inevitable. In order to best utilize the above methods for improved simulation (both hindcasting and forecasting), a blending of useful and reliable information from measurements, and physical experiments with numerical model results, has been broadly developed. This blending process, called data assimilation (DA), has been applied in atmospheric modelling for a few decades, and currently is becoming more widely used in oceanography, due to increased monitoring of oceanic data in space and time [1,2].

2. Methodology

A variety of data assimilation approaches have been applied to enhance modelling capability and accuracy using observations from different sources [3]. The algorithms have varying degrees of complexity of implementation, and they improve model results with varying degrees of success. This work will allow researchers to directly compare most common data assimilation algorithms being used in operational coastal hydrodynamics. The suitability of practical data assimilation algorithms for hindcasting and forecasting in

shallow coastal waters subjected to alternate wetting and drying using data collected from radars was assessed.

3. Results and Discussion

Cross-comparison among different DA algorithms were undertaken. Results indicated that a forecasting system of surface currents based on the three-dimensional model EFDC (Environmental Fluid Dynamics Code) and the HFR data using a Nudging algorithm was considered the most appropriate for Galway Bay. Because of its ease of implementation and its accuracy, this data assimilation system can provide timely and useful information for various practical coastal hindcast and forecast operations.

4. Conclusions

In summary, the assimilation of remotely sensed HF radar data using a nudging algorithm is a powerful tool for improving model performance. This research presented evidence of the effects of changes in nudging parameters and data assimilation cycle lengths on hydrodynamic forecasting, when applying this algorithm. The nudging algorithm has been shown to be particularly useful when updating is applied at each model computational timestep. These forecasts can provide useful information for a variety of applications, such as search and rescue and oil spill operations.

5. Acknowledgement

This research was supported by China Scholarship Council (CSC), National University of Ireland, Galway (NUIG) and Basic Start-up Research Fund by Sun Yat-sen University (76170-18831100). We would like to thank Informatics Research Unit for Sustainable Engineering (IRUSE) for providing the weather data, Oregon State University (OSU) for providing the OTIS tide software, and Ireland’s High-Performance Computing Centre (ICHEC) for providing computation service.

References

1. Marmain, J.; Molcard, A.; Forget, P.; Barth, A.; Ourmières, Y. Assimilation of HF radar surface currents to optimize forcing in the northwestern Mediterranean Sea. Nonlinear Processes in Geophysics 2014, 21, 659-675.

2. Schmid, C.; Majumder, S. Transport variability of the Brazil Current from observations and a data assimilation model. Ocean Science 2018, 14, 417-436.

3. Bowler, N.E.; Clayton, A.M.; Jardak, M.; Jermey, P.M.; Lorence, A.C.; Wlasak, M.A.; Barker, D.M.; Inverarity, G.W.; Swinbank, R. The effect of improved ensemble covariances on hybrid variational data assimilation. Quarterly Journal of the Royal Meteorological Society 2017, 143, 785-797.

Python-based Graphical User Interface for a Lattice Boltzmann Model Solving the Shallow Water Equations

Elysia Barker 1,*, Jian Zhou 1 1 Department of Computing and Mathematics, Manchester Metropolitan University, Manchester, M1 5GD * Correspondence: Elysia Barker, [email protected]

Keywords: lattice Boltzmann method; shallow water equations; GUI; Python; MATLAB

1. Introduction

The lattice Boltzmann model for the shallow water equations (LABSWE) [1,2] is an effective and competitive way of describing shallow water flows and it has become a very successful modern numerical method in computational hydraulics for water flow problems. In order to provide an interactive and efficient way of modelling shallow water flows using this method without going into detailed code, it is essential to develop a front-end graphical user interface (GUI). In this paper, Python is applied to develop a GUI for fast and simple use of the model without knowledge of programming to solve shallow water problems in practical engineering.

2. Methodology

Python is used as a basis to develop a graphical user interface to launch the LABSWE as Python has become an increasingly powerful programming language which is widely used in software engineering [3] and becoming a more and more popular choice in science and engineering [4]. There is an excellent integrated development environment for Python (IDLE) [5], which is used along with several imported packages such as MATLAB engine [6], Python imaging library (PIL) [7], and tkinter [8]. Using a combination of these packages, the front-end graphical user interface (GUI) for the LABSWE was developed by integrating the IDLE with the LABSWE coded in MATLAB. This allows data input into the GUI to run the LABSWE program and simulate shallow flows; and the corresponding results are then depicted using flow velocity vectors.

3. Results and Discussion

Custom data for initial conditions and geometries of the problem can be inputted into the GUI to start the simulations. This interface is clear and simple, allowing users to input data into the program without having to understand the code itself so the implementation of the LABSWE can be easily achieved and the results are then shown through a plot of flow parameters such as velocity vectors, which can be applied to identify flow characteristics for further research.

Fig.1 shows the GUI: the left graph displays the initial state of the GUI and the right graph gives an example for one flow case over time. The interface consists of various input parameters such as the computational nodes in the x and y directions, length and width of

computational domain such as a channel or a river, Manning’s coefficient for channel/bed friction, and other computational parameters such as time step and spatial step. The LABSWE takes these variables from Python and uses them to simulate water flows. In this case as shown in the figure, a water flow around a cylinder is modelled as presented in Fig.2, in which the correct flow field has been demonstrated through the velocity vectors.

Fig.1 Initial GUI interface for input data and initial setup (Left) Interface after data input and simulations, particularly right bottom subgraph shows dynamic visualization with time (Right)

Fig.2 Flow pattern with velocity vector flow around a solid cylindrical object

4. Conclusions

In this paper, the development of the GUI using Python for easy implementation and application of the LABSWE is reported. This provides a fast way of using this method without knowing the detailed programming to model shallow water flows in water engineering. The GUI is simple and easy to use. The methodology may be extended to other numerical methods for efficient solutions to problems encountered in science and engineering.

References

1. Zhou, J. (2002). A lattice Boltzmann model for the shallow water equations. Computer Methods in Applied Mechanics an Engineering. 191(32), pp.3527-3539 2. Zhou, J. (2004). Lattice Boltzmann Methods for Shallow Water Flows. Springer- Verlag. 3. https://www.python.org/about/apps/ (06/06/2019) 4. https://www.techrepublic.com/article/why-python-is-so-popular-with-developers-3-reasons-the- language-has-exploded/ (09/06/2019) 5. https://docs.python.org/3/library/idle.html (03/06/2019) 6. https://uk.mathworks.com/products/matlab/matlab-and-python.html?requestedDomain= (03/06/2019) 7. https://en.wikipedia.org/wiki/Python_Imaging_Library (07/06/2019) 8. https://www.tutorialspoint.com/python/python_gui_programming.htm (01/06/2019)

Research on Morphological Characteristics of Rip Current in Dadonghai, Sanya Xi Feng1,*, Bixuan Dong, Jun Kong, Weibing Feng 1 Hohai University, Nanjing 210098, P.R.China * Correspondence: Xi Feng, [email protected]

Keywords: rip current, morphological characteristics of rip current, headland beach, nearshore circulation, numerical simulation

1. Introduction

Dadonghai is located in Sanya, Hainan Province, China. It is a natural headland beach. The third quarter of each year is the most frequent period that rip current often occurs in Dadonghai. Rip current is a kind of nearshore wave-generated current. It has fast speed and almost perpendicular to the shoreline, which often leads to drowning accidents in coastal tourist areas. It is also one of the "killers" of beach safety. Since the 1940s, researchers have carried out scientific research on the generation mechanism and influencing factors of rip current. Castelle [1] et al. classified the rip currents into three categories and six sub- categories according to the different mechanisms of how rip current induced. The six types of rip current are, for example, shear instability rips, channel rips, etc. Short and Maslink [2] discussed the effect of headland structure on break-zone circulation in 1999. The hydrodynamic circulation of headland beach was divided into three modes: (1) normal beach circulation (2) cellular beach circulation (3) transitional beach circulation. The corresponding rip currents are normal rips, headland rips and transitional rips. Castelle and CoCo [3] studied the development of rip current on headland beach in 2012. On this basis of Castelle and CoCo’s research, Razak [4] used Xbeach model to explore the shape of break zone circulation and the development of rip currenrt under different wave heights. The study of rip current in China started very late. There are few studies on the morphology and mechanism of rip current under the actual topography. As the most representative headland beach in South China, it is of great significance to study the morphological characteristics of the rip current in Dadonghai. In this paper, numerical simulations were carried out on triple-nested grid domains by utilizing Delft3D Flow- Wave coupling model. The model was validated against measurements of tidal level and wave. The tidal level is verified by the measured tidal level data of Sanya, Dongfang, Beihai and Hailingshan Island. The measured wave data of Janson-3 satellite altimeter is used to verify the wave height. The hydrodynamic conditions in the innermost region are calculated by the outer grid. The nested model is shown in Figure 1.

Previous researchers believed that the alongshore currents would lead to headland rips when they encounter rigid boundaries such as breakwaters, headlands and so on. The simulation results show that in the absence of rip channels, there would be no rips near the headland and sometimes there would be a large circulation, which is caused by the

reciprocating current with rotation in the tidal current of Dadonghai. In the case of rip channels, the rip current was occurred in the rip channels. Then, the influences of the number and location of the rip channels on the generation and intensity of the rip current were further discussed. The simulation results showed that under the same hydrodynamic conditions, when there was only one rip channel, there would be obvious rip current and the flow velocity was about 0.2m/s. When there were two rip channels, the rip current does not induce. When there were three rip channels, the rip current existed at the channels, but the intensity of the rip currents was weaker than that of a single channel.

Through the analysis of the simulation results, the following preliminary conclusions are drawn:

1. There were no rip current in Dadonghai under the condition of uniform coastline. In the case of rip channels, rip current would occur at the rip channels. The flow and velocity pattern of channel rips are shown in Fig. 2.

2. The rips in Dadonghai belongs to the channel rips. The reason is that the existence of channels leads to the asymmetry of the coastal topography. When waves propagate to the coast, the asymmetry of the topography will produce different wave surges, which would generate pressure gradient. The pressure gradient made the alongshore currents gathered and flow to the sea.

3. The number of rip channels has a certain influence on the generation and intensity of rip current.

Figure1.Bathymetry of numerical nesting model. (a)is computation scope of layer 1;(b) is computation scope of layer 2; (c) is computation scope of layer 3.

Figure 2. (a) Flow field in the terrain with rip channels; (b)The velocity map under the topography with rip channel.

References

1. Castelle B, et al., Rip current types, circulation and hazard[J]. Earth-Science Reviews, 2016. 163:1-21.

2. Short A D, Masselink, G. Embayed and structurally controlled embayed beaches. In: Short, A.D. (Ed.), Handbook of Beach and Shoreface Morphodynamics[J]. 1999. Wiley, Chichester, pp. 230–250.

3. Castelle B, Coco G. The morphodynamics of rip channels on embayed beaches[J]. Continental Shelf Research, 2012, 43(none).

4. Razak M S A, Dastgheib A, Suryadi F X, et al. Headland structural impacts on surf zone current circulations[J]. Journal of Coastal Research, 2014, 70:65-71.

Performance Prediction of Ice-classed Propeller Churui Wan1, Weiping Kong1, Ju Ding1,2*, Jianqiang Wang1, Zhenghao Liu1, Min Zhou1 1 Marine Design & Research Institute of China Shanghai, China 2 Water Jet Propulsion Laboratory Shanghai, China * Correspondence: Churui Wan, [email protected]

Keywords: ice-classed propeller; pressure fluctuation; cavitation; blocking effect.

1. Introduction

An important problem of ice breaker propellers design is the choosing of blade parameters to provide less cavitation at extremely low speed and high power rates in very thick ice condition. Problems which are deficiently investigated are the following: the forming and behavior of the cavitation systems near the blades, especially taking into account the presence of the ship hull and ice block. Sea trials and model tests of icebreaker propellers have always shown the cavitation working at bollard pull and ice-breaking modes1. In this paper the results of numerical simulations using URANS for the cavitation pattern of ice- classed propellers are presented. The open water calculation results are compared with the experimental results. Then the numerical simulations of bottom fluctuating pressure are performed at the same as the test conditions in the cavitation tunnel and compared with the experimental results.

2. Methodology

Model tests to measure fluctuating pressure of cavitation flow on an ice-classed propeller were carried out in SSRI K15 Cavitation Tunnel. The principal particulars of the test section of SSRI K15 Cavitation Tunnel are summarized in Table and the set-up of ice block and propeller is shown. The diameter of the model propeller was 248mm in this research. The propeller rotation speed was set with the thrust identity method based on the results of open water test in a towing tank.

A commercial CFD software FLUENT was used for the numerical simulations, in which the cavitation flow solved by a mixture model based on a single-fluid multiphase mixture flow approach. The grid near the detection point is especially refinement. In order to save time, the steady calculation is used first, and then change to the unsteady calculation. Calculating conditions include cavitation and non-cavitation flow. As the numerical model for cavitation flow, Schneer & Sauer(2001)2 was applied in this research.

3. Results and Discussion

Firstly, the open water performance of propeller is numerically studied. The comparison between numerical calculation results and experimental results is shown. Near the design conditions, the calculated results are almost consistent with the test results, with an error of

less than 1%. This proves the validity of the calculation method.

The other work was to study the fluctuating pressure on the bottom of a ship under different working conditions. The results with and without cavitation are compared with the experimental results, respectively. The numerical results show that the fluctuating pressure frequency is consistent with the blade frequency and the amplitude is also close to the experimental results in cavitating flow. However, when cavitation occurs, the fluctuating pressure amplitude increases rapidly, but it is still smaller than the experimental results. Obviously, when cavitation occurs, the flow field environment will change dramatically. Accurately capturing the evolution process of cavitation is the key to predict fluctuating pressure.

4. Conclusions

Numerical simulation and experimental studies were presented in this paper. A computational domain including a block in front of ice-classed propeller was used to simulate directly the wake field for ice blockage. Some pressure sensors are arranged above the propeller to measure the fluctuating pressure at the bottom of the ship. The predicted results of fluctuating pressure in non-cavitation flow show high accuracy. When cavitation occurs, the flow field structure becomes complex and the fluctuating pressure increases sharply. The inaccurate prediction of cavitation morphology evolution leads to large deviation of fluctuating pressure results.

For future work, it is necessary to improve the prediction accuracy of fluctuation pressure in cavitation flow. The first is to improve the grid, which needs to be encrypted between the bottom and the blades. In a word, capturing the evolution of cavitation is the key to solve the problem.

5. Acknowledgement

The study was supported by the Foundation of Science and Technology on Water Jet Propulsion Laboratory (No. 6142223180101)

References

1. Lobachev M, Saifullin T, Taranov A, et al. CFD application for an icebreaker propeller design[C]//Proceedings of the Fifth International Symposium on Marine Propulsors- smp’17. 2017: 398-403.

2. Schnerr G H, Sauer J. Physical and numerical modeling of unsteady cavitation dynamics[C]//Fourth international conference on multiphase flow. ICMF New Orleans, 2001, 1.

Parametric Sensitivity Studies on Sloshing of a Layered Fluid

Obai Kargbo1,2, Mi-An Xue1,2, Jinhai Zheng1,2 1 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210024, China 2 College of Harbour Coastal and Offshore Engineering, Hohai University, Nanjing 210024, China * Correspondence: Obai Kargbo, [email protected]

1. Introduction

Sloshing refers to the motion of a fluid having a free surface due to the motion of its confined environment. The effect of sloshing motion is that it transmits hydrodynamic forces on the boundaries of its domain structure or environment, with the propagation of sloshing waves. Layered sloshing further complicates these dynamics as it has the tendency of creating internal waves which transmit energy and loadings on internal structures. A numerical Model was developed to study the layered sloshing phenomenon in a rectangular fluid domain having a free surface and an interfacial layer between the layered fluid boundaries. The behaviour of the internal wave is studied with internal wave time-series and spectral analysis being observed for various fluid-fluid layer height ratios of the layered fluid, with the effect of sloshing input parameters such as excitation amplitude and frequency being considered. The model was compared with available experimental literature and results showed that it was able to effectively conduct studies on the layered sloshing phenomenon.

Session 2: Hydro-environment Modelling I

Effects of River Mouth Progradation on the Evolution of River Longitudinal Profile

Weilun Gao1, Dongxue Li1, Zheng Bing Wang1,2,3, Dongdong Shao1,*, and Baoshan Cui1,* 1 State Key Laboratory of Water Environment Simulation and School of Environment, Beijing Normal University, Beijing, China 2 Deltares, Delft, The Netherlands 3 Delft University of Technology, Delft, The Netherlands * Correspondence: Dongdong Shao, [email protected], Baoshan Cui, [email protected]

Keywords: river longitudinal profile; river mouth progradation; numerical modeling

1. Introduction

River channel is typically characterized by a concave upward profile along longitudinal direction. Previous studies such as [1] [2] [3] have investigated the effects of sediment abrasion, distributary, subsidence, and water diversion etc. on the evolution of river longitudinal profiles. Although outbuilding delta [2] has been theoretically recognized as one of the driving factors contributing to the formation of concave upward profile, how river mouth progradation affects the evolution of river longitudinal profile is still elusive. In this study, numerical experiments were conducted to quantify the contribution of river mouth progradation to the formation of the concave upward profile measured by a proposed concavity index and equilibrium parameter.

2. Methodology

A 1-D numerical model, which incorporated shallow water equation, Engelund and Hansen’s formula for total bed-material transport, and Exner equation for evolution of channel bed level, was developed to simulate the evolution of river longitudinal profile. Constant bank-full discharge and sediment load were imposed at the upstream boundary, whereas a constant water level (0 m) and progradation rate of river mouth were prescribed at the downstream boundary. The initial river bed, with a river length (L) of 200 km, was set to a linear bed level at its equilibrium slope. Changes of river width, distributaries, subsidence and abrasion of sediment were neglected in this study. Simulation scenarios with different combinations of specific river discharges (qw, 0.2-25

m2/s), sediment concentration (Cs, 0.1-10 kg/m3), river width (B, 100-500 m), sediment

grain size (D50, 0.065-0.5 mm) and river mouth progradation rate (, 0-0.001 L per year).

A concavity index, , which was defined as the ratio of  and m (the bed level at half way the river length), was proposed to quantify the concavity of the river longitudinal

profile. Bed level difference  was defined as (u+d)/2-m, where u and d are the bed levels at the upstream and downstream river boundary, respectively. A dimensionless

equilibrium parameter, Te, which was defined as the ratio between the potential sediment

load to keep the equilibrium slope and the sediment load supplied at the upstream boundary, was proposed to quantify the ability of the river channel to maintain the quasi- linear profile.

3. Results and Discussion

Overall, the concavity of the river longitudinal profile as well as its increasing rate over time increase with increasing river mouth progradation rate when other parameters were kept constant. The results confirmed that the progradation of river mouth contributed to the formation of the concave upward profile. Theoretical analysis of the equilibrium parameter revealed that the equilibrium parameter correlated positively with sediment grain size, progradation rate and river length, and negatively with specific river discharge and sediment concentration. The relationship between the proposed concavity index, ,

and equilibrium parameter, Te, suggested the existence of a critical equilibrium parameter

Te,cr in the range of 0.1-1. The river channel attained a quasi-linear or concave profile below

or above Te,cr, respectively. Once a concave profile formed, the concavity tended to

increase with increasing Te.

4. Conclusions

Numerical results in this study confirmed that the progradation of river mouth contributed to the formation of the concave river profile. The relationship between the

proposed concavity index, , and equilibrium parameter, Te, suggested the existence of a

critical equilibrium parameter, Te,cr, above which a concave profile tended to form.

5. Acknowledgement

This work was supported by the Key Project of National Natural Science Foundation of China (Grant No. 51639001), the Joint Funds of the National Natural Science Foundation of China (grant U1806217), and the Interdisciplinary Research Funds of Beijing Normal University.

References

1. Blom, A., E. Viparelli and V. Chavarrías. The graded alluvial river: Profile concavity and downstream fining. Geophysical Research Letters. 2016, 43(12): 6285-6293.

2. Sinha, S. K. and G. Parker. Causes of Concavity in Longitudinal Profiles of Rivers. Water Resources Research. 1996, 32(5): 1417-1428.

3. Wang, Z. B., Wang, Z. Y., and de Vriend, H. J. Impact of water diversion on the morphological development of the Lower Yellow River. Int. J. Sediment Res. 2008, 23(1), 13–27.

Application of MIKESHE Model in Water Environmental Management for Anning River Basin

YuTong Li1,* 1 Beijing Normal University, Beijing 100875, China * Correspondence: YuTong Li, [email protected]

Keywords: MIKESHE hydrological integrated model; hydrological response; water environmental management; hydrologic cycle

1. Introduction

So as to comprehensively analyze hydrological environment system of watershed, Coupling surface water and groundwater is especially important for the entire hydrological cycle. AnNing river basin, located in Southwestern Sichuan Province, was selected as the research area to build a MIKESHE hydrological integrated model to simulate the surface runoff. Land use and precipitation changes contribute to the hydrological changes in the basin. Meanwhile, the MIKESHE model is used to quantitatively evaluate the impact of land use and precipitation changes on watershed hydrology. The hydrological response in the AnNing river Basin was explored. The integrated hydrological model was setup based on MIKESHE for the simulation year of 2006 to 2015. The preliminary results showed that it is feasibile to apply the MIKESHE model in the study area for water environmental management. It can provide reference for understanding the application potential of this model in the southwest mountainous area and regional water resources management. Furthermore, some valued suggestions and perspectives about the water environmental problems in the study for the future were provided.

Hydrologic Response to Land Use Changes in the Upper Paraná River Basin

Sameh Adib Abou Rafee1,2*, Cintia Bertacchi Uvo1, Jorge Alberto Martins3, and Edmilson Dias de Freitas2 1 Division of Water Resources Engineering, Lund University, 22100 Lund, Sweden 2 Department of Atmospheric Sciences, University of São Paulo, São Paulo 01000, Brazil 3 Federal University of Technology, Parana, Londrina 86000, Brazil * Correspondence: [email protected]

Keywords: discharge; SWAT model.

1. Introduction

Several studies have demonstrated that the main rivers in the world are showing significant changes in their stream flows due to changes in land use and land cover or climate, generating apprehension regarding the increase in the frequency of drought and flood events. The Upper Paraná River Basin (UPRB) has presented a significant increase in their stream flows in the last decades. According to Doyle and Barros [1] the main causes for this growth are the increase in precipitation and the reduction in evapotranspiration process due to land use changes. These changes occurred mainly in Paraná and São Paulo Brazilian states, located in the UPRB, that reduced more than 70% of its primitive forest in the last century, where the deforestation was replaced for different uses such as for agriculture and pasture areas [2].

In this study, we estimated the hydrologic response to land use and land cover in the UPRB. For this purpose, the land use scenarios of 1985 and 2015 were simulated.

2. Methodology

The study area comprises the UPRB with the drainage area of around 900,480 km2. UPRB is located in the central-southern region of Brazil, which covers six Brazilian states (São Paulo, Paraná, Mato Grosso do Sul, Minas Gerais, Goiás, and Santa Catarina) and a Federal District (Figure 01). Currently, UPRB has an estimated population of more than 65 million inhabitants, with 93% of its population living in urban areas. The region has the highest demand for water resources in Brazil equivalent to 736 m3 s-1, where most are used for agricultural (42%) and industrial (27%) activities.

The hydrological simulations were performed using the 2012 version of the Soil and Water Assessment Tool (SWAT) model with an ArcGIS interface. SWAT is an open source, semi- distributed, and physical model widely used to simulate several impacts that interfere on hydrologic and water quality of water resources, such as transport of nutrients and pesticides, as well as climate and land use change scenarios [3,4]. SWAT execution for UPRB was based on an already calibrated and validated (from January 1984 to December 32

2015) model by Abou Rafee et al. [5]. SWAT was run using the land use and land cover data of 1985 and 2015 obtained from the Rudke [6] classification.

3. Results and Discussion

The results of scenarios indicated that the land changes occurred between 1985 and 2015 increased the discharge up to 5% in the main tributaries of UPRB such as in Paranaiba, Grande, Tietê, Paranapanema, Iguaçu, and Paraná rivers. Regarding the small watersheds of the basin, the simulated results showed an increasing (decreasing) more than 33% (50%).

4. Conclusions

Besides a better understanding of the UPRB hydrology, the results outcomes of this work could be used as information for managers and policy makers in order to improve planning and sustainable management of water uses in the basin.

5. Acknowledgement

The authors would like to gratefully acknowledge Å ke & Greta Lissheds foundation, CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), PROEX and Process nº 88887.115875/2015-01 for their financial support.

References

1. Doyle, M.E.; Barros, V.R. Attribution of the river flow growth in the Plata Basin. Int. J. Climatol. 2011, 31, 2234–2248.

2. Tucci, C.E.. Impactos da variabilidade climática e do uso do solo nos recursos hídricos. Câmara Temática sobre Recur. Hídricos 2002, 150.

3. Neitsch, S..; Arnold, J..; Kiniry, J..; Williams, J.. Soil & Water Assessment Tool: Theoretical Documentation Version 2009; 2011;

4. Arnold, J.G.; Srinivasan, R.; Muttiah, R.S.; Williams, J.R. Large Area Hydrologic Modelling and Assessment Part I : Model Development. Am. Water Resour. Assoc. 1998.

5. Abou Rafee, S.A.; Uvo, C.B.; Martins, J.A.; Domingues, L.M.; Rudke, A.P.; Fujita, T.; Freitas, E.D. Large-Scale Hydrological Modelling of the Upper Paraná River Basin. Water 2019.

6. Rudke, A.P. Dinâmica da cobertura do solo para a bacia hidrográfica do alto rio Paraná. Master´s Thesis, Federal University of Techonology Parana, Londrina, Brazil, 2018.

Study on Ecological Water Requirement of Hongze Lake for Bird Habitat Protect

Jinglan Qin1,* 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Jinglan Qin, [email protected]

Keywords: ecological water requirement; bird habitat; wetland plants; Hongze Lake

1. Introduction

Ecological water requirement plays an important role in the protection of ecological environment. Specific hydrological conditions are the driving forces of wetland formation and maintenance. In the process of wetland ecological protection and restoration, water level is the key to affect the distribution pattern of wetland plants. The dynamic change process of wetland plant community can reflect the health degree of wetland ecosystem and its ecological service function. Wetland plants provide the main habitat and food source for birds, and play an important ecological role in maintaining bird diversity and protecting rare birds. Based on multi-source remote sensing data and geographic cellular automata (Geo-CA) as the model framework, a segmented LC-Logistic-CA model is constructed in this study. The relationship between the hydrological process of Hongze Lake and the distribution pattern and dynamic change characteristics of wetland plants from 2013 to 2018 was studied quantitatively. And the spatial pattern of plant community in Hongze Lake in 2019 was simulated and predicted. The ecological effects and maintenance mechanism of wetland plant pattern diversity caused by water level change on bird diversity protection and rare birds were analyzed, in order to determine the optimal ecological water level needed to protect bird habitat. The study shows that the proper ecological water level can ensure the proper lake wetland area, maintain the basic integrity of the lake wetland ecosystem, give full play to its ecological function, and provide a good habitat for birds. The results can provide scientific basis for rational allocation of water resources and protection of bird habitat in Hongze Lake.

Wind Effects on Hydrodynamics and Implications for Ecology in a Hydraulically Dominated Shallow Lake System: Chagan Lake Xuemei Liu1, Guangxin Zhang2,*, Yao Wu2 1 Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China 2 University of Chinese Academy of Sciences, Beijing 100049, China * Correspondence: Guangxin Zhang, zhgx@ iga.ac.cn

Keywords: shallow lake; hydrodynamic model; wind forcing; Chagan Lake

1. Introduction

Lakes are important ecosystems with high productivity and biodiversity around the world [1]. Hydrodynamic plays a critical role in controlling the physical processes of mass mixing and transport in lake areas, especially in shallow lake which is more vulnerable to disturbance of the wind [2]. Chagan Lake is one such example, so it is necessary to study the wind how to effect on hydrodynamics and implications for ecology. In this study, a 2D hydrodynamic model is used to simulate the hydrodynamics in Chagan Lake forced by realistic inflow, outflow and wind drivers and to further investigate the wind effects on spatial and temporal flow patterns based on a series of wind scenarios, in order to support the water quality and water ecology management.

2. Methodology

Field observation and numerical models of lake water is a common research tools for lake hydrodynamic. The DELFT3D suite is composed of several modules grouped in a common interface that can be easily linked to each other. DELFT3D-FLOW, one of the modules of this suite, is a multi-dimensional (2D or 3D) hydrodynamic/transport simulation program that calculates non-steady flows and transport phenomena resulting from meteorological forcing [3].

3. Results and Discussion

The observed and simulated hydrodynamic situation showed a good fit and can be used to quantitatively assess wind effects on the hydrodynamics and implications for ecology. Simulation results showed that the hydrodynamic indexes (water level, flow velocity, water depth) and salinity of Chagan Lake has obvious hour, daily, monthly and seasonal variation. The simulation scenario includes tow prevailing wind directions (NNE and SW) with 3 wind-speed (5 m/s, 10 m/s and 25 m/s) scenarios, including temperature and salinity, were further simulated to determine the wind effects. There are four wind-dominated zones, the circulation patterns were influenced by the wind direction and wind speeds. The low-speed SW wind was found to be the most important factor in the western regional 35

of the lake and the high-speed NNE wind was found to be the most important factor in the southern regional. The change of salinity was consistent with the change of flow field. These results can provide support for further quantitative analysis of water quality and the evolution of ecological systems in the lake. It is unclear how transport pollutants with the flow field.

4. Conclusions

The current study is the ﬁrst to investigate the relationship between hydraulic and wind forcing in shallow lake. In additional, our simulation results revealed that hydrodynamic indexes were most influenced by the low-speed in western regional and high-speed in southern regional in the lake. The study provides the physical mechanisms in local, wind- dominated zones of Chagan Lake and has important implications for ecological variations. Based on these findings, we conclude that the intensity (significant or not) and effect (speed or direction) of wind on hydrodynamics temporally varied and spatial varied at hourly, daily, monthly, seasonal scales.

5. Acknowledgement

This work was supported by the National Key R&D Program of China (2017YFC0406003), National Natural Science Foundation of China (Grant Nos. 41877160)

References

1. Schindler D E, Scheuerell M D. Habitat coupling in lake ecosystems [J]. Oikos, 2002, 98(2): 177-189.

2. Yao J, Li Y, Zhang D, et al. Wind effects on hydrodynamics and implications for ecology in a hydraulically dominated river-lake floodplain system: Poyang Lake[J]. Journal of Hydrology, 2019, 571: 103-113.

3. Hydraulics D. Delft3D-FLOW User Manual: Simulation of multi-dimensional hydrodynamic flows and transport phenomena [R]. Including sediments. Technical report, 2014.

Study on Eco-water Requirement Accounting Method Based on Regime Shifts of Shallow Lakes Xintian Qiu1,* 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Xintian Qiu, [email protected]

Keywords: Shallow lake; Ecological water requirement; Regime shifts; Ecological water level; Simulation model

1. Introduction

Water level is usually regarded as the main characteristic index of lake ecological water Requirement. How to calculate reasonable lake ecological water level to ensure the health and stability of lake ecosystem is an important aspect of lake ecological water requirement accounting. In order to realize the shfit of shallow lakes from turbid water dominated by algae to clear water dominated by submerged plants, the calculation method of suitable ecological water level of lakes is constructed. Lake Baiyangdian in north China plain was taken as a case study for this research, the total phosphorus concentration (PW) in water and the coverage of vegetation (V) were used as the indicators to measure the regime shifts of the lake. A mechanism-driven,mathematical model was established to simulate the dynamics of ecosystem state changes in a shallow lake under different influent phosphorus concentration (Pw, in) and different residence time (τ). In order to provide decision-making basis for ecological dispatch of water conservancy project of Lake Baiyangdian, the optimum period of water residence time for realizing the optimal result of regime shifts under different inflow conditions is explored and the suitable ecological water level under each inflow flow is calculated.

Session 3: Hydro-ecology Modelling

Analysis of Ecological Hydrological Variation in the Upstream of Baiyangdian Basin Based on Iha-Rva

Yingshan Sun1,3, Qiang Liu1,2,*, Qingguo Li3 1 The Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing Normal University, Beijing 100875, China 2 School of Environment, Beijing Normal University, Beijing 100875, China 3 School of water resources and environment,University of Jinan,Jinan 250000,China * Correspondence: Qiang Liu, liuqiang@ bnu.edu.cn

Keywords: IHA; RVA; Flow regime alteration; hydrological variation

1. Introduction

The biodiversity and integrity of river ecosystems are depend on the natural flow regime, which are characterized by ecologically relevant hydrological indicators derived from river flow data. However, climate change and human activities such as water diversion, dam construction and urban development have changed the natural flow of rivers around the world [1]. Changes in fluidity are considered to be a major cause of degradation of river ecosystems. Therefore, assessing fluidity changes becomes a fundamental step in river protection and recovery. Therefore, an effective method is needed to evaluate the flow state change. The Variability Method (RVA) [2] is the most widely used multivariate method for assessing fluidity changes.

2. Methodology

In this paper, the Range of Variability Approach is used to analyze the runoff variation, from 1959 to 2016, in the upstream of Baiyangdian Basin. Firstly, the mutation time of the runoff sequence of was obtained by Mann-Kendall test. And then the variation of natural flow was analyzed by IHA-RVA. This method is based on a set of 33 indicators called IHA, which were developed by Richter et al. An RVA target for each of the IHA indicator is set depending on the natural flow. Then, the flow data that are under the influence of disturb are compared with these targets. Runoff data comes from the Hydrographic Yearbook published by the Ministry of Water Resources, including Zijingguan, Zhongtangmei, Daomaguan, Dongzicun and Fuping hydrological stations.

3. Results and Discussion

The variation result of the five groups of IHA indicators through RVA are: (i) the average monthly flow of the five hydrological stations are decreased, with the monthly average flow decreased most in March, April, June and July; (ii) the extreme flow value of the five stations during the change period are significantly lower than the flow value of the reference period, and the maximum hydrological change of the maximum daily flow is the largest;(iii) the maximum flow occurrence time of the five stations is advanced to March, 39

and the minimum flow occurrence time is advanced to January, and the advance time is longer; (iv) the number of minimum stream occurrences and the number of maximum stream occurrences decreased, only Zhongtangmei increased on the contrary; (v) the average rate of increase in flow during the five-station change period is higher than the decrease rate, and the number of reversals is significantly reduced.

4. Conclusions

Through the upstream runoff situation analysis, the key indicators of hydrological variation in the upstream of the Baiyangdian Basin are the mean flood flow in June and July, the annual extreme flow occurrence time and the high flow delay. According to the ecological impact corresponding to the IHA indicator parameters, the river runoff in June and July is lower than the baseline period, which has an adverse effect on the reproduction of aquatic organisms. The time of occurrence of annual extreme flow is advanced, threatening the stability of the habitat of river, to a certain extent. It will change the spawning time of fish and the behavioral process during the breeding period. The high flow delay will reduce the development of animal and plant ecosystems on the river bank. The study will provide a reference for local ecological protection and restoration work.

5. Acknowledgement

This study was supported by the National Natural Science Foundation of China (No. 51579008), and Major Science and Technology Program for Water Pollution Control and Treatment (2018ZX07110001).

References

1. Wang Y;Wang D.;Wu J.Assessing the impact of Danjiangkou reservoir on ecohydrological conditions in Hanjiang river, China. Ecological Engineering, 2015, 81:41-52.

2. Richter B D.;Baumgartner J V.;Braun P D P.A Method for Assessing Hydrologic Alteration within Ecosystems. Conservation Biology, 1996, 10(4):1163-1174.

Numerical Investigation on Characteristics of Vortices at Equal-Width Open-Channel Confluences

Cheng Zeng1,*, Jie Zhou2, Zhou Zhou1, Shaowei Ding1, and Lingling Wang1 1 College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China 2 College of Mechanics and Materials, Hohai University, Nanjing 210098, China * Correspondence: Cheng Zeng, [email protected]

Keywords: combining flows; numerical simulation; Renolds stress model; vortices

1. Introduction

The confluence of open channel flows is a commonly phenomenon in water-related projects. The flow structure in the junction region is complicated and three dimensional. Separation zone and shear face generate most turbulence in confluence junctions. The turbulence is anisotropic and leads to strong secondary circulations in the downstream main channel. The characteristics of flow velocities at the junction are complex and have a direct impact on the design and maintenance of channels.

Figure 1 shows the generalized model of flow characteristics in channel confluences. In the existing studies, the open-channel combining flows generally shows the following characteristics. After the junction area, the branch channel inflow is squeezed and mixed with the main flow. The streamline is bent and the flow velocity is deflected. The flow separation zone appears near the junction wall on the converging side [1]. At the same time, the outer layer of the separation zone is squeezed and the flow rate becomes greater, forming a shrinkage zone.

Figure 1. Generalized model of flow characteristics in channel confluences

2. Methodology

In the present study, the 3D flow pattern at the confluences of two rectangular channels with right angle is simulated with Reynolds Stress Model. The governing equations are solved by the Finite Volume Method (FVM) and the flow is analyzed in terms of unsteady state. The volume of fluid (VOF) method is used to capture the interface of the water and air. The Weber’s experimental findings of right-angled combining flows are used to test the validity of the numerical model. Comparison of the numerical results and the experimental data indicates a close proximity in mean velocity profiles, water surface elevation profiles and resolved turbulence quantities.

3. Results and Discussion

The 3D pattern of backwater was analyzed after the simulations of 21 combined conditions

for 3 discharge ratios (q = Qu/Qd = 0.25, 0.417 and 0.75) and 7 junction angles (θ = 30°, 45°, 60°, 65°, 75°, 85° and 90°). The results show that for identical discharge ratio, a greater junction angle leads to larger values in length and width of separation zone. When the discharge ratio equals to 0.25 or 0.417, the impact of junction angle is more significant. Otherwise, when the discharge ratio equals to 0.75, the impact is insignificant. For an identical junction angle, a greater discharge ratio leads to a smaller value in length of the separation zone. The relationship between the discharge ratio and the values of length and width of separation zone is nonlinear. The nonlinear relationship is more obvious with a greater junction angle.

4. Conclusions

Based on the Reynolds Stress Model (RSM), a 3D numerical model for the open-channel combining flows with equal width is established. The complex 3D characteristics of the vortices behind the junction are studied with the numerical experiments. The results show that the size of the vortices in separation zone is dependent on the discharge ratio and junction angle. A greater junction angle or smaller discharge ratio leads to a stronger vortex structure in separation zone.

5. Acknowledgement

This work was supported by the National Key R&D Program of China (2017YFC0405605) and the Fundamental Research Funds for the Central University (Grant no. 2016B05114).

References

1. Best, J.L.; Reid I. Separation zone at open-channel junction. J. Hydraul. Eng. 1984, 110, 1588-1594.

2. Weber L.J. Experiments on flow at a 90º open-channel junction. J. Hydraul. Eng. 2001, 127, 340-350.

Hydrological Processes Governing the Ecological Degradation of Isolated Wetlands in Nenjiang River Basin

Yuexin Zheng1, Yanfeng Wu1,2 and Guangxin Zhang1,* 1 Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China 2 University of Chinese Academy of Sciences, Beijing 100049, China * Correspondence: Guangxin Zhang, [email protected]

Keywords: wetlands modules; hydrological processes simulation; contribute area; Water balance variability

1. Introduction

Wetlands, known as the "kidney of the earth", process important hydrological, biogeochemical and ecological functions within a watershed. Due to climate change and human activities, isolated wetlands (IWs) area shrank numerously and their functions are gradually deteriorating or completely lost [1]. Hydrological elements are the main driving factors governing evaluation and degradation of wetlands [2]. Investigation of degradation mechanism with respect to hydrological processes variability is the basis of ecohydrology research, and is one of the hot issues in domestic and foreign research. In this study, we used PHYSITEL/HYDROTEL modeling platform with two wetland distribution sceneries (isolated wetland/riparian wetland) to quantitatively evaluate the hydrological mechanism of wetland degradation in Nenjiang River Basin.

2. Methodology

The isolated wetlands and their contribute area were obtained from PHYSITEL. The hydrological processes of IWs and their contribute area were simulated using validated HYDROTEL with specific IWs module in two study areas (UHRH2375 and UHRH2911) where wetlands area decreased considerably [3]. The evapotranspiration, infiltration as well as inflow, volume and area of IWs were simulated and investigated to systematically evaluate water balance variation caused by land use change.

3. Results and Discussion

The simulation results show that the IWs area in UHRH2375 and UHRH2911 decreased by - 43.95% and - 82.85% from 1978 to 2015, respectively. The transformation from wetland to grassland and dry farmland mainly contribute to area loss of IWs in two-study area. Simultaneously, evapotranspiration decreased by 57.41% and 27.46% in UHRH2375 and UHRH2911, respectively. However, due to abundant increase in infiltration in the contribute area of IWs, the inflow decreased by 33.58% and 42.02%. Consequently, the IWs

volume and area experienced a substantial reduction. This indicated that land use transformation in contribution area could alter hydrological processes that are key driving factors governing water balance of IWs.

We investigate how and to what extent water balance changed cause by land use in the contribution area of IWS. Wetlands water balance monitoring data (e.g., soil moisture measurements, wetland area, evapotranspiration, water table and local groundwater stage levels) should be utilized to further validate our model as they become available. How much specific land use type should be kept to maintain a sustainable hydrological regime of IWs in a watershed or a contribution area? These latter considerations will be reported in a future paper.

4. Conclusions

This study used the PHYSITEL/HYDROTEL distributed hydrological modelling platform to investigate hydrological processes governing the ecological degradation of isolated wetlands within Nenjiang River Basin. Our simulation results revealed that although total evapotranspiration decreased due to land use transformation, inflow and volume decreased numerously as a result of abundant increase in infiltration in the contribution area, which led to severe shrink of IWs in the study area. The transformation from wetland to dry land and grassland contribute to continuously water deficiency and eventually induced area shrink of IWs. Our results indicated that land use change altered hydrological processed in the contribute area and interior of IWs and eventually induced ecological degeneration of IWs. Hence, protection and rehabilitation of damaged wetlands become necessary and essential to maintain significant flow regulations and beneficial effect to water resources management.

5. Acknowledgement

This work was supported by the National Key R&D Program of China (2017YFC0406003), National Natural Science Foundation of China (Grant Nos. 41877160), the Featured Institute Project 4, the Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences (IGA-135-05).

References

1. Xu-chun Ye; Yuan-ke Meng; Li-gang Xu; et al. Net primary productivity dynamics and associated hydrological driving factors in the floodplain wetland of China's largest freshwater lake. Science of The Total Environment, 2019, 659: 302-313.

2. Sica, Y; Quintana, R; Radeloff V; et al. Wetland loss due to land use change in the Lower Paraná River Delta, Argentina. Sci. Total Environ. 2016, 568, 967–978.

3. Fossey M.; Rousseau A.N.; Bensalma F.; Savary S.; Royer A. Integrating isolated and riparian wetland modules in the PHYSITEL/HYDROTEL modelling platform: model performance and diagnosis. Hydrol. Process., 2015, 29: 4683-4702.

Impact of Three Gorges Reservoir on Spawning Activity and Eco-hydrologic Conditions of Four Major Chinese Carps in the Middle of Yangtze River, China

Wenxiang Guo1,* 1 Water Resources School, China * Correspondence: Wenxiang Guo, [email protected]

Keywords: Three Gorges Reservoir; Yichang station; eco-hydrological conditions; four major Chinese carps

1. Introduction

Silver carp, bighead carp, grass carp, and black carp, namely the four major Chinese carps, are commercially important aquaculture species in China. The flow regime alternation of rivers also brings an impact on the spawning and reproduction conditions of four major Chinese carps in the lower reaches of the reservoir. To investigate into the change in hydrological conditions and spawning and reproduction performances of fishes during the spawning period of four major Chinese carps before and after impoundment of Three Gorges Reservoir, a quantitative analysis of the relevance between such hydrological parameters as flow, water level, sediment concentration and water temperature of Yichang Station and larvae runoff of the four species during their spawning period was carried out. As suggested by the results, when four major Chinese carps are spawning, the proper hydrological parameters would be 11,000-15,000m3/s for flow, 43.0-46.0m for water level, 0.01-0.21kg/m3 for sediment concentration and 4-8d for water rise, and 22-24℃ for water temperature. Among those values, water rise and sediment concentration appear to be in significant positive correlation with the larvae abundance of four major Chinese carps, and thus remain as critical factors for their larvae runoff. After the impoundment of Three Gorges Reservoir, the declining trend in flow, water level and water temperature during the spawning period of four major Chinese carps is not significant when compared with that in sediment concentration (by over 98%). The spawning and reproduction time of four species also gets retarded due to the late-coming proper water temperature, so does the spawning scale. The proportions of four carps also change a lot, with silver carp ascending to be at the highest ratio among them. This study can provide a reference for the protection of important fishes in the lower reaches of Three Gorges Reservoir.

Quantitative Assessment on Watershed-Scale Hydrological Services of Wetlands

Yanfeng Wu1,2, Guangxin Zhang1,*, and Alain N. Rousseau3 1 Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China 2 University of Chinese Academy of Sciences, Beijing 100049, China 3 INRS-ETE / Institut National de la Recherche Scientifique – Eau Terre Environnement, 490 rue de la Couronne, G1K 9A9 Quebec City, Quebec, Canada * Correspondence: Guangxin Zhang, zhgx@ iga.ac.cn

Keywords: wetlands modules; hydrological processes simulation; baseflow support; quickflow mitigation; hydrological function

1. Introduction

Wetlands, one of the three major ecosystems (wetlands, forest and marine ecosystem) that are important part of the natural ecological space in the world, play an important role in hydrological functions and processes that underlie a range of potential ecosystem services. Despite recognizing the importance of hydrological function of wetlands, watershed-scale wetlands services have rarely been investigated [1,2]. In this study, we used the PHYSITEL/HYDROTEL modelling platform with pairs simulated scenarios (i.e., with/ without wetlands) to quantitatively assess the hydrological function of watershed-scale wetlands in Duobukuli River Basin (DRB), namely streamflow regulation, flood mitigation and baseflow support.

2. Methodology

The PHYSITEL/HYDROTEL distributed hydrological modelling platform was used to assess the effects of wetlands on watershed hydrology; quantifying their contribution to the streamflow regime [3]. The validated HYDROTEL was used to simulate hydrological processes during 2000~2017 with two scenarios: with and without the wetland modules (WW and WOW, respectively). The median value of each hydrological indicator obtained from IHA software (Indicators of Hydrologic Alteration Version 7.1) was calculated by the nonparametric method, to quantitatively assess wetland impact on streamflow regime.

3. Results and Discussion

The observed and simulated streamflow showed a good fit and can be used to quantitatively assess the hydrological function of watershed-scale wetlands in DRB. Simulation results showed that wetlands exert significant impact on watershed hydrological processes by decreasing streamflow and altering streamflow regime (magnitude, frequency, duration and time of flow events). The intensity (significant or not) of wetlands influences on quickflow had daily, monthly and annual variation. Wetlands

significantly attenuated quickflow during flood season while slightly support daily, monthly and annual baseflow. The average quickflow attenuation and baseflow support of wetlands were 5.89% and 0.83%, respectively. Although the intensity and effect (mitigation or augment) of wetlands on streamflow temporally varied at daily, monthly, seasonal and annual scales, wetland overall mitigated quickflow and augment baseflow in Duobukuli River Basin. It is unclear how and to what extent streamflow alternated with respect to changes in wetlands types, location and area.

4. Conclusions

Our paired simulation results revealed that wetlands played an important role in regulating watershed hydrology in DRB, namely decreased streamflow and altered streamflow regimes. In addition, compare to baseflow, wetlands exerted considerable impact on daily, monthly and annual quick flow, especially most obvious during flood season. The average mitigation and augment effect of wetlands on quickflow and baseflow were -5.89% and 0.83%, respectively. Based on these findings, we conclude that although the intensity (significant or not) and effect (mitigation or augment) of wetlands on streamflow temporally varied at daily, monthly, seasonal and annual scales, wetland overall mitigated quickflow and augment baseflow in Duobukuli River Basin.

5. Acknowledgement

References

1. Wu Y.F.; Zhang G.X. Review of development, frontiers and prospects of wetlands eco- hydrological models (in Chinese with English abstract). Acta Ecologica Sinica, 2018, 38: 2588-2598．

2. Yeo I.Y.; Lang M.W.; Lee S.; McCarty G.W.; Sadeghi A.M.; Yetemen O.; Huang C. Mapping landscape-level hydrological connectivity of headwater wetlands to downstream waters: A geospatial modeling approach-Part 1. Sci Total Environ, 2018, 653: 1557-1570.

Response of Carbon Emission to Fluctuation of Water Level in a Typical Shallow Wetland

Xiaomin Yuan1,2, Qiang Liu1,2,* 1 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China 2 Key Laboratory for Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Qiang Liu, [email protected]

Keywords: wetland, carbon emission; DNDC; water fluctuation

1. Introduction

Fluctuation of water level controls the biochemical processes [1], and also influences the carbon emission in the shallow wetland [2]. The changes of carbon emission changing with the fluctuation of water level alter the wetland function as a carbon sink or sources [3]. In present study, impacts of depth, duration and frequency of inundation on wetland carbon cycle have brought great attention. We modeled the response of carbon emission to changes of water level using a process-based biogeochemical model, denitrification- decomposition (DNDC) model, which is used to explain effects of fluctuation of water level on wetland function in the typical shallow wetland, Baiyangdian Lake.

2. Methodology

Table 1 Simulation scenarios based on fluctuating water level Scenarios frequency duration/day timing/month Scenario 1 1 10 February Scenario 2 1 10 July Scenario 3 1 10 October Scenario 4 1 27 February Scenario 5 1 27 July Scenario 6 1 27 October Scenario 7 2 54 February and July Scenario 8 2 54 February and October Scenario 9 3 81 February, July and October

In order to reveal the response of carbon emission to water level fluctuation, wetland module in DNDC were used to simulate CO2, CH4 emission in different water level scenarios. Methane and carbon dioxide fluxes were modelled in the constant water depth of -50 cm to 10 cm. And then nine scenarios were selected according to the depth frequency, duration and timing of inundation. The coefficient of determination (R2) was used to indicate the correlation between the observed and simulated results. Daily meteorological data, e.g., precipitation, air temperature, were collected from National Meteorological

Information Center, China Meteorological Administration. Daily water levels were collected from Baoding water resources bureau. And the basic physical and chemical properties of the soil were acquired from standard field sampling and laboratory analysis. The biomass partitions were set as 55%, 22% and 22%. The C/N ratio were set as 21.8, 175.2 and 41.9, respectively, for reeds.

3. Results and Discussion

The annual water level presented a decreased trend from 1951 to 2019, ranged from 5.43 m to 9.49 m. The monthly water level changing between 6.68 m and 7.50 m. Yet, from 2006 to 2011, the maximum monthly water level occurred in December to March and the minimum water level occurred in July mostly. It indicated that water level does not coincide with the vegetation growth period.

The wetland DNDC were suitable to simulate the fluxes of carbon dioxide and methane in which coefficient of determination (R2) for methane and carbon dioxide were 0.58 and 0.77, respectively.

For the constant water depth from -50 cm to 10 cm, the carbon dioxide fluxes increased with the elevated water depth, which varying from 32.3 kg C/ha/d to 49.3 kg C/ha/d. And the methane emission did not presente linear trend with changes of water level. However, both carbon dioxide and methane fluxes showed a significant change with water depth of - 10 cm to 10 cm.

Both carbon dioxide and methane flux increased with inundation lasting time. The carbon dioxide flux varied from 7015.21 kg C/ha/d to 7865.44 kg C/ha/d, and the methane flux changed between -0.73 kg C/ha/d and 12.98 kg C/ha/d. According to the slope of the flux curve, the minimum slope appears when the inundation periods is 27 days.

Carbon dioxide and methane should be increased with the increase of fluctuate frequency. And the flux would increase by 12.65% and 712.26% when the fluctuate frequency adding to three times per year from once a year.

Consider with the fluctuating timing, no significant differences were found in carbon dioxide emission. Contrary to carbon dioxide, methane emission flux presented a significant change with fluctuating at 95% confidence level. Methane emission is 1.8 kg C/ha/d in July, while the flux is negative in February and November (-1.65 kg C/ha/d and -2.08 kg C/ha/d, respectively). It indicates that fluctuation of water level may trigger methane emission, which will alter the role of wetland as carbon sink or source.

4. Conclusions

Fluctuation of water level, resulted from climate changes and human activities, is inconsistent with the plant phenology, which has led to the abnormal of carbon emission. In present study, wetland module of DNDC present suitable results to simulate the changes of carbon emission. The depth, duration, frequency, and timing of inundation altered carbon emission. Carbon dioxide is positive to water depth when it varying between -50 cm to 10 cm, while a small fluctuation (10 cm) in water level will have a 50

significant impact on methane fluxes. The results indicated the water level management should be conducted to maintain the balance of carbon emission in the shallow wetland.

5. Acknowledgement

This study was supported by the National Key R&D Program of China (No. 2017YFC0404505), and the National Natural Science Foundation of China (No. 51579008). The authors would also like to thank the National Meteorological Information Center of the China Meteorological Administration for providing the meteorological data used in this study.

References

1. Jacinthe, P. A. Carbon dioxide and methane fluxes in variably-flooded riparian forests. Geoderma, 2015, 241-242:41-50.

2. Xuchun Ye, Yuanke Meng, Ligang Xu, et al. Net primary productivity dynamics and associated hydrological driving factors in the floodplain wetland of China's largest freshwater lake. Science of the Total Environment, 2019, 695: 302-313.

3. Zhongmin H, Qun G, Shenggong L, et al. Shifts in the dynamics of productivity signal ecosystem state transitions at the biome-scale. Ecology Letters, 2018, 21: 1457-1466.

Session 4: Experiment and Software

Nanoparticle Impregnated Beads for In-Situ Removal of Nitrate from Contaminated Groundwater: Experimental Study and Mathematical Modelling

Fatemeh Bahrami1, Yanchun Zou1,2, Yong Sun1,3, and Guangzhi Sun1,2,* 1 School of Engineering, Edith Cowan University, Joondalup, WA 6027, Australia 2 Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China 3 Department of Chemical and Environmental Engineering, University of Nottingham Ningbo, Zhejiang Province, 315100, China * Correspondence: Guangzhi Sun, [email protected]

Keywords: alginate; floating beads; iron nanoparticle; remediation

1. Introduction

Excessive amount of nitrate in groundwater is a serious environmental problem that remains largely unsolved despite intensive studies. Dissolved nitrate from fertilizers and wastes often seep through soil into the groundwater, creating a health and environmental hazard. For decades, researchers worldwide have been searching for effective technologies to remove nitrate from contaminated groundwater. Among various technologies, using nanoparticles to treat the groundwater has demonstrated significant potentials, as reactive nanoparticles can bind nitrate ions onto their surfaces; acting as adsorbents and reactants to transform and immobilize nitrate.

Nano zero-valent iron (NZVI) particles are known for their abilities to chemically reduce nitrate-nitrogen (NO3-N), by acting as electron donors under anaerobic condition. Several studies have demonstrated that nitrate reduction to ammonium, albeit counter-intuitive, is a promising technical route to tackle the problem of groundwater contamination. Relative to nitrate, ammonium has much greater affinity to surfaces and is prone to be immobilized by common adsorbents [1]. This technical route can be made feasible by: (a) enabling effective contact between NZVI and nitrate under anaerobic condition, (b) immobilizing ammonium (the product of nitrate reduction), and (c) allowing the NZVI and immobilized ammonium to be recovered from the water. While being impregnated with NZVI and magnetic (recoverable in an artificial magnetic field), floating alginate beads appear to match the requirements for in-situ nitrate reduction and immobilization processes to take place in groundwater. Prior to this study, impregnated beads as magnetic, floating ‘reactors’ for groundwater remediation had never been investigated. This paper reports the results from a series of experimental and modelling studies of using synthetic alginate beads, impregnated with NZVI and magnetite Fe3O4 (MNP) nanoparticles, to treat nitrate contaminated groundwater.

2. Methodology 53

Alginate beads were synthesized by adding NZVI (40–60 nm) and MNP (50–100 nm) nanopowders to sodium alginate solution, followed by reactions with calcium carbonate (CaCO3) and acetic acid acetic acid (CH3COOH). Two types of alginate beads, nonfloatable and floatable, were synthesized. A standard nitrate solution was diluted with milli-q water to synthesize contaminated waters of 1, 10, and 100 mg/L NO3-N. Cylinder nitrogen gas was used to purge dissolved oxygen from the waters. Batch (beaker) experiments were carried out to study the efficiencies of NZVI embedded in the alginate beads for reducing NO3-N under different conditions. A mathematical model, describing nitrate transfer from bulk water into the beads, were developed based on: (a) theories of diffusion through layers of spherical objects, and (b) various assumptions and simplifications (e.g. all beads being of same size and functionality). A MATLAB program was coded based on the model, enabling the calculations of NO3-N concentration gradients across the alginate beads.

3. Results and Discussion

The impregnated alginate beads were analyzed by optical microscopy, scanning electron microscopy (SEM), fourier-transform infrared spectroscopy (FTIR), and Brunauer, Emmett and Teller (BET) analysis, for their surface characteristics and functional groups. The results from batch experiments demonstrated that the beads impregnated with mixtures of NZVI-MNP nanoparticles had greater nitrate reduction abilities than those impregnated with only NZVI. Compared with directly dosing NZVI into water, entrapment into the beads decreased their efficiencies as electron donors to reduce nitrate, but the decrease in efficiency was moderate. It was found that 10 g/L dosage of NZVI-MNP into 100 mg/L NO3-N solution reduced nitrate concentration by 61% in 48 h. In comparison, the same amount (in dry mass) of NZVI-MNP nanoparticles reduced NO3-N concentration by 48%, when they were immobilized in floating alginate beads to treat the same water with the same retention time and dosage (in g/L, where g represents the mass of NZVI). The MATLAB simulation results, derived from a scenario of reducing initial concentration of 100 mg/L NO3-N by non-floating beads impregnated with 15 g/L NZVI-MNP, yielded the profiles of NO3-N changes with time and distance across the beads.

4. Conclusions

This study demonstrated significant potential of using alginate beads impregnated with NZVI and MNP nanoparticles for in-situ removal of nitrate from contaminated water.

References

1. Comba, S.; Martin, M.; Marchisio D.L.; Sethi, R. Reduction of nitrate and ammonium adsorption using microscale iron particles and zeolitite. Water, Air, Soil Pollution, 2012, 223, 1079-1089.

Impact of Structures of Different Scale on Heat Transfer and Performance of Proton Exchange Membrane Fuel Cells

Yuan Gao1,*, Zhu Rui1 1 School of Automotive Studies, Tongji University, Shanghai 201804, China. * Correspondence: Yuan Gao, [email protected]

Keywords: heat transfer; PEM fuel cell; mesoscopic

1. Introduction

The performance of proton exchange membrane fuel cells (PEMFC) is affected by temperature and needs to operate at a suitable condition. Therefore, thermal management of PEMFC is very necessary. This study aims to make the temperature of the PEMFC more controllable through structural optimization and verify it by computer simulation. The structural optimization is divided into two parts with different scales: one is to increase the heat transfer capacity of the PEMFC by optimizing the pore structure inside the fuel cell, which is mesoscopic and mainly related to the catalytic layer and the diffusion layer; the other is to enhances the efficiency of heat exchange by optimizing the structure of water channels, which is macroscopic mainly related to the structural parameters of the bipolar plates. According to the simulation results, the evaluation of the heat transfer capacity of different structural schemes is given and analyzed.

(a) (b) Fig. 1. 3D image of the reconstructed catalytic layer(a) and the real catalytic layer(b)

References

1. H. Pourrahmani, M. Moghimi, M. Siavashi. Thermal management in PEMFCs: The respective effects of porous media in the gas flow channel. International Journal of Hydrogen Energy, 44 (2018) 3121-3137.

2. G. Lei, W.R. Li, Q.Z. Wen. The convective heat transfer of fractal porous media under stress condition. International Journal of Thermal Sciences, 137 (2019) 55-63.

Investigation on Computing Method of Martian Dust Fluid based on the Energy Dissipation Method

Tianxiang Ding1, Xuyan Hou1,*, Guangyu Cao1, Liyan Liu1, Jixuan Liu1, and Zongquan Deng1 1 State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001, China * Correspondence: Xuyan Hou, [email protected]

Keywords: Martian dust fluid; energy dissipation method; particle deposition; DEM-CFD

1. Introduction

The high-intensity and high-frequency dust storm environment of Martian surface causes a series of challenges to the operation of a Martian rover in Martian detection missions. The NASA’s Opportunity rover, which was stroke by a planet-encircling Martian dust storm and finally lost contact with NASA since June 10th, 2018, was such a good example. Therefore, it is necessary to investigate the effect of Martian dust particles to Mars rovers. In this paper, an initiative Martian dust fluid simulating research based on the energy dissipation method was developed to simulate the deposition process of Martian dust fluid which was caused by surface adhesion between particles and Martian rovers. Importantly, this study provides a theoretical basis for Martian dust protection and Martian exploration mission.

2. Methodology

Firstly, an energy dissipation model of particles based on discrete element method (DEM) was established because of characteristics of Martian dust particles such as tiny size and viscoelasticity, etc. This model is based on the existing DMT model to analyze collision deposition of dust fluid particles, including particle-spacecraft collision and particle- particle collision. Secondly, this paper analyzed characteristics of particles after their first collision, then established the stochastic model of critical wind speed for particle deposition process. Finally, a series of simulation of Martian dust fluid particle deposition process were done based on DEM-CFD.

3. Results and Discussion

Under the condition of particle-spacecraft collision deposition, the critical wind speed for

particle deposition process Vc1 and its probability density can be calculated as followed.

5 2 4 2 2 1  −−1 WWW= + =17.66 *3 Er * 3 3 + 1.41 CErVWmVW  * 3 * 3 3 ,  = 2 −  AAvAd A1 AcBcA 1 1 1 2 (1)  5 2 4 2 2 1 11 1 −−−  mV2= W +17.66  *3 E * 3 r 3+ 2 C * 3 E * 3 r 3 m22  W 2 c1 A B 2 B 2 B

 fX() fRfrfr()()() fVdr() drdr== dr X Rrr 1212  Vcc1 11212   JXZ () VRc1 /  1 (2) VVgVgccc11315 mmWB  =+  RgmRWgmR35B  Under the condition of particle-particle collision deposition, the critical wind speed for particle deposition process Vc2 and its probability density can be calculated as followed.

2234229 2  −−− 5 1 WWWEm=+=+=− RVCEm6.120.49, RVWmVW ***2 5555555  CCvCdpCcpCcDcC 222 2 (3)  23222 1 9 1 −−− − 10  mVWERWCmERW2***=+ 8.080.91 55555 + 2 2 cCpDBpDD2 fRfrfrfrfr()()()()()  RrCrCrDrDCCDD1212 1212  fVdrVcCCD() drdrr21122=  c 2  VR/  c2 (4) VVhVh mmW  ccc22325=+D   RhmRWhmR35D Figure 1 shows the simulation model of particle deposition process based on DEM-CFD. The Martian dust fluid particle had a decreasing velocity during the deposition process and finally adhered to the spacecraft surface. Figure 2 shows the critical wind speed for particle deposition process with different particle sizes. It can be seen from Figure 2 that a particle with a larger diameter has a higher critical wind speed.

Figure 1 Simulation model of particle deposition process based on DEM-CFD

Figure 2 Critical wind speed for particle deposition process with different particle sizes

Wake Characteristics and Near-field Mass Transport Processes through a Fishing Net Panel

Li Huang1, Dongdong Shao1,*, Carlo Gualtieri2 1 State Key Laboratory of Water Environment Simulation & School of Environment, Beijing Normal University, Beijing 100875, China 2 Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Napoli 80125, Italy * Correspondence: Dongdong Shao, [email protected]

Keywords: fishing net panel; wake characteristics; transport processes; PIV-PLIF; porous media model; OpenFOAM

1. Introduction

Cage-based aquaculture has been growing rapidly in recent years, which results in clustering of large quantities of cages in fish farms located in inland lakes and reservoirs and coastal embayment. As a key component of the cage, the fishing net is a kind of small- scale, flexible structure, and the flow field and mass transfer process around the net are complex [1]. Some experimental and numerical studies have been carried out to explore the velocity reduction factor and drag coefficients for nets with different solidities, but there are few experiments focusing on the turbulent characteristics and transfer process downstream of a fishing net or cage. Therefore, a physical experiment and numerical simulation were conducted in this study to measure velocity field and concentration field around a fishing net, which will be the basis for the study of the cage.

2. Methodology

The experiments were conducted in a recirculating flume. The velocity and concentration field were measured using combined PIV and PLIF. A user-defined passiveScalarPisoFoam solver was developed based on the pisoFoam and scalarTransportantFoam solvers in the open source software OpenFOAM. The RANS turbulence model and porous media model were used in the numerical simulation. The flow field and concentration field around the net were simulated with different incoming velocities and solidities.

3. Results and Discussion

For the same incoming velocity, the velocity decays more dramatically with increasing solidity, which is consistent with the results reported in previous studies [2]. The velocity reduction factor is negatively correlated with the incoming velocity. The turbulence intensity downstream of the net increases initially and then decreases and levels off at the end. The turbulence intensity peaks demarcate the turbulence production region from the turbulence decay region. In the turbulent production region, the lateral distribution of turbulence intensity exhibits a wavy distribution corresponding to the net structure, with

larger values appearing after twines, which is asynchronous with the lateral distribution of time-averaged velocity. Compared with the grid-generated turbulence experiment conducted in the wind tunnel, the inhomogeneity of the wake flow field behind a net is more significant. The lateral distribution of the time-averaged concentration of the passive scalar flowing through the net exhibits a self-similar Gaussian profile. The distribution of the time-averaged concentration along the longitudinal direction depends on the position of the image window relative to the mesh, and is also influenced by the turbulence development process of the wake flow. The numerical results agree well with the experimental results, and show that the velocity has a more significant effect on the plume spreading width, which appears to be negatively correlated with incoming velocity.

4. Conclusions

The results suggested that the time-averaged velocity and turbulence intensity are dependent on the net property and incoming flow velocity. The spreading plume downstream of the net followed Gaussian profile, and the variation of the time-averaged concentration alone the longitudinal direction depended on the location of the measurement plane. The net restricted the mixing and spreading of the plume. The numerical results agree well with the experimental results.

5. Acknowledgement

This work was financially supported by the National Natural Science Foundation (NSFC) Project Nos. 5177090256

References

1. Bi, C.-W., Y.-P. Zhao, G.-H. Dong, T.-J. Xu, and F.-K. Gui. Experimental investigation of the reduction in flow velocity downstream from a fishing net. Aquacultural Engineering. 2013,57,71-81.

2. Tsukrov, I., O. Eroshkin, D. Fredriksson, M. R. Swift, and B. Celikkol. Finite element modeling of net panels using a consistent net element. Ocean Engineering. 2003, 30, 251- 270.

CFD Investigations of Transient Cavitation Flows Based on Weakly-Compressible Model in Pipeline

Xuelin Tang1*, 2, Hui Gao1, Xiaoqin Li1, 2 and Xiaoyan Shi1, 2 1 College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China 2 Beijing Engineering Research Centre of Safety and Energy Saving Technology for Water Supply Network System，China Agricultural University，Beijing 100083， China * Correspondence: Xuelin Tang, [email protected]

Keywords: weakly-compressible model; turbulence model; transient flow; cavitation

1. Introduction

With rapid developments in computer capabilities and Computational Fluid Dynamics (CFD), CFD is a mature technology and reliable engineering tool for analyses of hydraulic engineering problems, including hydraulic transient in pipes [1]. Martins [2] et al. used CFD to analyze of the hydraulic transient flows in pressurized pipes, and the calculated velocity profiles demonstrated two regions with different behaviors: the wall region dominated by the fluid viscosity showing flow changes are faster with sharp gradients and the pipe core strongly dependent on the fluid inertial forces. Wang [3] et al. combined 1D method of characteristics and the 3D finite volume method of CFD based on OpenFOAM open source CFD software to carry out transient simulations of hydraulic system caused by the valve closing/opening in a pipe.

2. Methodology

The density-pressure equation, which reflects the variable wave speed of the compressible fluid, was incorporated into governing equations to from the weakly-compressible Reynolds-Averaged Navier-Stokes (RANS) model for hydraulic transients, in which the turbulence model RNG k- was employed. Firstly, the numerical simulations of the non- cavitating transient caused by the fast valve closure in the Reservoir-Pipe-Valve (RPV) system are investigated. In the CFD model solver, a constant pressure assigned at the upstream boundary and at the downstream boundary respectively, and the boundary condition at the wall is described by the no-slip condition, the secondary order discrete scheme for the time term and the convection term, and the central difference for the diffusion term were employed for the discretization of governing equations, and the SIMPLEC scheme was used to solve the discretization equations. Secondly, the cavitation model was further incorporated into the above-mentioned governing equations for further simulations of turbulent transients with cavitation.

3. Results and Discussion

For non-cavitation flows, the CFD results showed that the flow is stopped in the valve section, an invert flux near the wall is generated. The predicted wall shear stress of the hydraulic transient was strongly dependent on the time history of the local velocity variation near the wall. Furthermore, the simulation results can enrich the flow field information such as velocity and pressure distributions. Through the evolution of the pressure field, the propagation characteristics of pressure waves, including shape, peak and phase, can be analyzed qualitatively and quantitatively. Through the evolution of the velocity field, it can be seen that the velocity distribution in the wall area changes rapidly and has a high gradient, which mainly depends on the viscosity, and the change of the velocity distribution in the core region is related to the velocity distribution of the history of the past time, which mainly depends on the diffusion. For cavitation flows, the formation, development and collapse of the cavity can be successfully captured, where cavitation cavity is presented by the vapor volume fraction, and it can be clearly and visually observed that the uneven distribution of vapor cavity in the direction of pipe length and pipe diameter, and move slowly along the top of the pipe wall. If the rarefaction wave propagates into a zone of decreasing pressure, the vaporous cavitation region will form. Alternatively, the rarefaction wave propagating into a zone of increasing pressure does not result in the formation of the vaporous cavitation zone. The predicted results well reproduced the time-dependent pressure evolutions of hydraulic transient with or without cavitation and agreed well with the relevant experimental.

4. Conclusions

The weakly-compressible RANS model for hydraulic transients with or without cavitation were proposed in combination with RNG k- and cavitation model for the RPV system. The computational results can provide the much more useful information including velocity, pressure and vapor volume fraction distributions. All the predicted results were compared with the relevant experimental. The analyses and comparisons showed that the simulation models and strategies are capable to well capture the transient flows.

5. Acknowledgement

This work was supported by the National Natural Science Foundation of China (Grant Nos. 51779257, 51479196, 51179192).

References

1. Zhou, L.; Liu, D.Y.; Karney, B. and Zhang, Q.F. Influence of entrapped air pockets on hydraulic transients in water pipelines. J. Hydraul. Eng. 2011, 137, 1686-1692.

2. Martins, N.M.C.; Soares, A.K.; Ramos, H.M. and Covas, D.I.C. CFD modeling of transient flow in pressurized pipes. Comput. Fluids 2016, 126, 129-140.

3. Wang, C.; Nilsson, H.; Yang, J. and Petit, O. 1D–3D coupling for hydraulic system transient simulations. COMPUT PHYS COMMUN 2017, 210, 1–9. 61

Distribution, Source and Tendency of Fe, Mn and Trace Metals in Urban Environmental Media

Xuan Chang1,*, Yingxia Li1 1 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Xuan Chang, [email protected]

Keywords: urban environmental media; heavy metals; urban river; source and tread

1. Introduction

Urban rivers and lakes are the final link of urban water cycle. They accept pollutants from rainwater pipelines and atmospheric deposition. Consequently, they are prone to deterioration of water quality, eutrophication and even black odor. Among them, heavy metals are one of the main pollutants, and some studies have shown that iron and manganese are the main components of water blackening [1]. Therefore, it is of great significance to study the distribution of heavy metal elements in urban environmental media, the source and trend of metal elements in urban rivers and the cause of formation of black and odorous water bodies.

2. Methodology

Firstly, the concentration of metal elements in sediment, water phase and atmosphere are collected in the literature. Combined with the concentration of metal elements in street dust measured in laboratory, the database of metal elements content in different urban environmental media is constructed. As for the acquired data, the arithmetic mean, geometric mean and median are selected as representative values by SPSS analysis of data distribution characteristics. In order to analyze the sources and trends of metal elements in urban rivers, the contents of metal elements are accumulated one by one, and the increasing sequence of metal elements in various media is obtained. Based on this, the multiple linear regression is carried out.

3. Results and Discussion

The descriptive statistics of Fe, Mn and trace metals concentrations in various urban environmental media are presented in the following table. It can be found that the content of iron in various environmental media is the highest, followed by manganese and zinc. This is basically consistent with the abundance of elements in the crust. Then a multiple linear regression model is constructed to explain the sources of metal elements in urban rivers. The results show that the fitting effect of the model is good (P<0.05, R2=0.978). Specifically, the negative coefficient of sediment indicates that it has adsorption effect on metal elements of water phase, while the positive elastic coefficient of the other two variables indicates that urban street dust and atmospheric deposition are the main sources of metal elements in urban rivers. Based on the above analysis, it can be explained that the black phenomenon is prone to occur in urban rivers due to the formation of FeS and MnS when polluted into anoxic reduction environment.

4. Conclusions

There are abundant iron and manganese elements in all environmental media of the city. Among them, urban street dust and atmospheric particulate matter are important sources of metal elements in urban rivers, while heavy metals entering river water phase are mainly deposited in sediment.

5. Acknowledgement

The authors are thankful for the support provided by the Fund for National Key Research & Development Program (2016YFA0602304), the State Key Program of National Natural Science of China (Grant number 41530635), Innovative Research Group of the National Natural Science Foundation of China (Grant number 51721093).

References

1. Liang, Z.; Siegert, M.; Fang W.; et al. Blackening and Odorization of Urban Rivers: A biogeochemical process. FEMS Microbiol. Ecol. 2017, 94(3).

Session 5: Hydraulic Modelling II

Effects of Obstacles on Lid-Driven Cavity Flows Using the Lattice-Boltzmann Method Andrew Cunningham*, Jian Zhou, and Jon Shiach 1 Department of Computing and Mathematics, Manchester Metropolitan University, Manchester, M1 5GD * Correspondence: Andrew Cunningham, [email protected]

Keywords: lattice Boltzmann method, cavity flow, single-relaxation time, numerical method

1. Introduction

The lid-driven cavity flow problem has been as a useful benchmark case to evaluate numerical models for solutions of incompressible flows and the Navier-Stokes equations [1]. With a plethora of industrial and engineering applications, such as coating and printing, many find this problem an attractive case to study [2]. Harbors are manmade structures to help shelter vessels and passengers from threats created by large bodies of sea water, such as waves, tide and storm surge. Usually they are enclosed spaces of water with a single inlet/outlet opening to sea, which may be simplified as a lid-driven cavity model for study on the flow phenomena that exists within these structures. For this the lid-driven cavity problem has been adapted to model flows within harbors to demonstrate how the flow adapts to new mediums such as solid objects, as well as changes to the shape of the cavity and the inlet for better management and control of a harbor.

2. Methodology The lattice Boltzmann method has shown promise as a novel numerical method for finding solutions for incompressible flows [3]. For this problem a single-relaxation time method was implemented developed by Bhatnagar, Gross and Krook, also known as the LBGK model [4], shown in eq (1), where fi(x, t) and fieq(x, t) are the particle and equilibrium density function, ei is the particle velocity along the ith direction, τ is the single-relaxation time parameter, x and t are the spatial and time steps respectively. A two-dimensional lattice configuration was used with nine velocity vectors with the subscript i = 0, 1, …, 8. 1 푓 (푥 + 푒 ∆푡, 푡 + ∆푡) − 푓 (푥, 푡) = − (푓 (푥, 푡) − 푓푒푞(푥, 푡) (1), 푖 푖 푖 휏 푖 푖 8 8

휌 = ∑ 푓훼 (2), 휌푢푖 = ∑ 푓훼푒훼푖 (3) 훼=0 훼=0 where u is velocity and  is density. A Zou-He boundary condition was implemented across the top of the cavity where the initial horizontal driving velocity u = 0.1 is applied. Around the rest of the cavity traditional bounce-back boundary conditions were executed [5]. 3. Results and Discussions A square cavity was first used to test the flow with just a single object within its center. Either a rectangle or a cylinder was used, using increasing values for the Reynolds number, Re for short. At low Re the flow speed around the object was congruent with negligible differences between the two shapes, however when increasing Re the cylinder had a much greater flow speed around it. The primary vortex was affected significantly by the object 65

as it was not able to fill the center of the cavity, instead moving to the top right side creating a larger downstream velocity. Then the cavity was adjusted using a ratio of 2:1 for the x and y axis, respectively. The initial inflow no longer spanned the top boundary of the cavity, instead going from the midpoint to the far righthand side of the cavity. Rectangular objects were used to represent ships anchored within the harbor. Three cases were tested at varying levels of Re. The first was a base case where no additional object were placed within the cavity. The next two cases added either six or nine stationary objects to fill the cavity; this represented a half- filled or full harbor respectively. The case configurations are shown in Fig.1. The base case showed similar results as to that of the benchmark tests set by Ghia [1] as expected. Once vessels were added the flow the primary vortex became distorted and took on an elliptical shape. When comparing the flow within the closed environment on the left- hand border between the three cases, once objects were added, the velocity was

considerably greater.

Fig.1

Velocity vector profile of a harbor at Re 5000. Left has no ships, middle has 6 ships and, the right has 9 ships within the domain. 4. Conclusion In this paper the lid-driven cavity is taken as a simple model for a harbor. The lattice Boltzmann method has been used to study the flows inside the harbor with additional solid objects added as ships to the cavity. Several harbors with different Reynolds numbers and various obstacles are considered. These results will help management and control of a harbor in ship engineering, particularly with a moored vessel.

References 1. Ghia U.; Ghia K.; Shin C. High-Re solutions for incompressible flow using the Navier- Stokes equations and a multigrid method. Journal of Comp Physics. 1982. 48. 387 – 411 2. Perumal D.; Dass A. Application of lattice Boltzmann method for incompressible viscous flows. Applied Mathematical Modelling. 2013, 37, 4075 – 4092 3. Huo S.; Zou Q.; Chen S.; Doolen G.; Cogley AC. Simulation of cavity flow by the lattice Boltzmann method. Journal of Comp Physics. 1995. 118. 329 – 347 4. Mohamad A. Lattice Boltzmann method: fundamentals and engineering applications and computer codes. Springer. 2011 5. Jozsa T.I.; Szoke M.; Teschner T.R.; Konozsy L.; Moulitsas I. Validation and verification of a 2D lattice Boltzmann solver for incompressible fluid flow. 2016. ECCOMAS Congress 2016. 1046 – 1060

Parallel Lattice Boltzmann Method for Shallow Water Equations on Quadtree Grids

Zhiming Ru1,* 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Zhiming Ru, [email protected]

Keywords: lattice Boltzmann method; shallow water equations; quadtree grid; parallel computing

1. Introduction

The lattice Boltzmann method (LBM), developed from the lattice gas automaton, is used to simulate the movement of the viscous fluid. According to the different schemes of the collision term, it can be divided into Bhatnagar-Gross-Krrok (BGK) scheme [1], multiple relaxation time (MRT) scheme [2], central moments (CMs) scheme [3], etc. Usually, a uniform gird is required by this method, but it means a huge amount of computations and long running time. Later, the multi-block grid is put forward to reduce the quantity of lattices [4]. Then, the quadtree grid is used for the LBM to improve the efficiency further [5, 6]. However, the tree-structured grid is hard in parallel, which means longer running time.

2. Methodology

The lattice Boltzmann method for shallow water equations (LABSWE) has a similar process with the LBM. In this study, three optional schemes of collision term are provided by different collision matrixes for the model. A smoothed quadtree grid with a minimum width is necessary for the model. At first, a primary grid is generated on the quadtree and every quadtree node stand for a unique square. In order to generate the smoothed grid, a 2-D array is supplied to map the lattices which are represented by the square peaks of the tree nodes. Then the lattices, located in the water basin, are numbered serially by some rules and saved in a file. Because of the complexity of grid, two functions (LevelIn and LevelOut) are summarized to simplify the process and most of the constituent processes can execute in parallel. Moreover, this study uses a perfect binary tree to ensure the consistency in time for lattices with different sizes. And specifically, the nodes of the same depth on the binary tree affect the lattices with same size. The two functions are tied to the left child nodes and right child nodes of the binary tree respectively. Base on the above regulations, after a preorder traversal of the binary tree, the time goes one same step for all lattices. The treatments of the edge between lattices with different size are same with Yu, et al. [4], but a modified spatial interpolation is used for LABSWE.

3. Results and Discussion

First of all, the lid-driven cavity flow is simulated by the LBM on a quadtree grid. The result shows that the presented model can decrease the running time. However, the error may increase with the ascending of the Reynolds number. According to the simulation of the wind-driven circulation in a dish-shaped basin by LABSWE, the result of the presented model agrees with the N-property problem. Two vortexes are simulated successfully under a uniform wind shear stress and the errors of velocities on the characteristic line exist because of the errors of the interpolations and the big gradient of the vorticity. Finally, this model is applied to the Danjingkou reservoir. After simulation of 180 days, the continuity equation is satisfied and the flow fields are smoothed. The model on the offered quadtree grid can save at least 40% running time compared with the same model on the uniform grid.

4. Conclusions

According to the tests, the presented model can utilize the performance of the multi-core processor maximally, and it is efficient and can decrease the running time obviously. It is necessary to use the more stable collision schemes such as MRT or CMs, even if it means more calculations. The error of the interpolations will be blow up at the high Reynolds number and the big gradient of the vorticity, which requests more accurate interpolation functions. It can be seen that the model can simulate the shallow water with moderate Reynolds numbers efficiently.

References

1. Bhatnagar P.; Gross E.; Krook M. A model for collision processes in gases. Physical Review. 1954, 94, 511-525.

2. D’Humieres D. Generalized lattice Boltzmann equations. In Rarefied gas dynamics: theory and simulations (ed. Shizgal B D & Weaver D P), Prog. Aeronaut. Astronaut. 1992, 159, 450 -458

3. Geier M.; Greiner A.; Korvink J.G. Cascaded digital lattice Boltzmann automata for high Reynolds number flow. Physical Review E. 2006, 73(6), 066705. 59.

4. Yu D.Z.; Mei R.W.; Shyy W. A muti-block lattice Boltzmann method for viscous fluid flows. International Journal for Numerical Methods in Fluids. 2002, 39, 99-120.

5. Chen Y.; Kang Q.; Cai Q.; et al. Lattice Boltzmann method on quadtree grids. Physical Review E Statistical Nonlinear & Soft Matter Physics. 2011, 83(2), 026707.

6. Eitel-Amor G.; Meinke M.; Schroder W. A lattice-Boltzmann method with hierarchically refined meshes. Computers & Fluids. 2013, 75(6), 127-139.

A Method for Defining the Scope of River-Lake Transition Zone Based on Velocity Gradient

Wei Yang1,*, Yanwei Zhao1, Kai Tian1, and Shicun Liu1 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Wei Yang, yangwei@ bnu.edu.cn

Keywords: velocity gradient; river-lake transition zone; hydrodynamic model

Abstract

As a connecting channel between rivers and lakes, river-lake transition zone plays an important role in material circulation, energy flow and information exchange, it is a research difficulty to define the scope. It is of great significance to scientifically define the scope for carrying out research on water quantity, water quality, water ecological environment and other aspects of the transition zone. Analysing the spatial location and morphological characteristics of the transition zone, and three types of boundary are determined, including land-water boundary, upper boundary and lower boundary. A method for determining the upper boundary by combining one- dimensional unsteady flow equation with flow continuity equation is established. A method for determining the lower boundary based on velocity gradient and hydrodynamic model simulation is proposed. Finally, a method for defining the scope of river-lake transition zone is formed. Taking the transition zones of Fuhe River, Xiaoyi River, Baigou River diversion and Baiyangdian as research objects, combining with the actual monitoring data and historical data, the functional relationship between flow velocity and distance along the river was established, the hydrodynamic model was constructed, the upper and lower boundaries were determined, and the actual scope of the transition zone was defined. The method for defining the scope of transition zone based on velocity gradient, it further perfects and enriches the method system of defining the scope of the river-lake transition zone, and lays a theoretical foundation for the protection of the water ecological environment in the river- lake transition zone.

1. Introduction

Rivers and lakes are the main forms of surface water, forming a river-lake transition zone with unique environmental characteristics, structure and function at the junction of rivers and lakes. Transitional zone is the link, source and sink between rivers and lakes, and the habitat of many marginal species [1]. It has particularity, dynamics, variability and complexity, and the definition of its scope has always been a research difficulty. At present, there are few studies on the transition zone, and there is no clear

and scientific definition of the scope of the transition zone. Based on this point, this paper carries out the research on the method of defining the scope of the river-lake transition zone, and strives to provide reference and basis for solving this problem.

2. Methodology

Upper boundary: In dry season, the function relationship between velocity and distance along the river is established by using the flow continuity equations; in wet season, the function relationship between velocity and distance along the river is established by means of one-dimensional unsteady flow equation group; By comparing and analyzing the two kinds of function relations, finding out the sudden change point of velocity, that is the position of the upper boundary [2].

The lower boundary: Using MIKE21 software, the hydrodynamic model of the transition zone is established, and the distribution of flow velocity in the transition zone is simulated. By analyzing the velocity gradient, finding out the velocity contour closest to the Lake velocity gradient, that is the lower boundary.

3. Results and Discussion

Analyzing the location of upper and lower boundary, combining with land and water boundary, the functional relationship between the area and time of transition zone is established, and the transition zone with the largest area is selected as the final result.

4. Conclusions

The method for defining the scope of transition Zone based on velocity gradient, it finds out the rule between the velocity and the upper and lower boundary during the wet season and dry season in the river-lake transitional zone, establishes the function of time and the area of the transitional zone, follows the dynamic and changeable characteristics of the scope of the river-lake transitional zone, and it is scientific and reliable.

References

1. Forman R.T.T.; Moore P.N. Theoretical foundations for understanding boundaries in landscape mosaics[M]//Landscape boundaries. Springer, New York, NY, 1992: 236- 258.

2. WANG X.; WANG Y.; XIAO W. H.; WANG G.; ZHU W.Y. Research on method of defining tail-reach of inflowing river [J]. Water Resources and Hydropower Engineering, 2013, 44(2): 44-47.

Uncertainty and Sensitivity Analysis of Phosphorus Model Parameters in Large Shallow Lakes

Yiping Li1,2,*, Yuanyuan Shi1,2, Yue Cheng1,2 1 Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, P.R.China 2 College of Environment, Hohai University, Nanjing 210098, P.R.China * Correspondence: Yiping Li, [email protected]

Keywords: Lake Taihu; generalized likelihood uncertainty estimation (GLUE); regionalized sensitivity analysis (RSA); phosphorus; EFDC model; diagenesis

1. Introduction

Lakes play a significant role in an ecosystem that can reflect the changes of the surrounding environment, and the formation of sediments is a "record" of the evolution of regional ecology [2]. In large shallow lakes, the surface sediments are susceptible to external wind field, hydrodynamics or human disturbance. The complex physical, chemical and biological reactions make the surface sediments extremely unstable. Therefore, the transferring and transformation of nutrients between ‘sediment-water’ interface is the key process affecting the aquatic ecosystem of shallow lakes [1].

2. Methodology

Lake Taihu was chosen as a typical large shallow lake, and diagenesis model of phosphorus was established based on EFDC (Environmental Fluid Dynamic Code) model. The uncertainty of simulation results and sensitivity of 16 parameters related to phosphorus migration and transformation in the diagenesis model was analyzed with Latin Hypercube Sampling method (LHS), Regionalized sensitivity analysis method (RSA) and Generalized Likelihood Uncertainty Estimation method (GLUE).

3. Results and Discussion

The temporal and spatial distribution of phosphate (PO4-P) and total phosphorus (TP) in Lake Taihu was extremely uneven, and the uncertainty of diagenetic module parameters had a strong impact on the simulation of PO4-P and TP. Uncertainty was significantly prominent in the southwest and the eastern lakes. The Southwest Lake was mainly connected with the lake bank, and the contour direction was consistent with the southeast wind direction, which was greatly affected by wind-driven currents. The coastline of the Eastern Lake was complex, major power drive of which was coastal inflow and lake currents. The uncertainty of TP in the Central Lake was significantly enhanced, while that in Meiliang Bay and East Lake Taihu was weakened, which indicated that the content of granular phosphorus and dissolved organic phosphorus in the Central Lake was influenced by the uncertainty of diagenetic module parameters. 71

Dynamic parameters were most sensitive parameters in most lakes, which indicated that phosphorus concentration in water body will be greatly affected in any underwater environment when parameters related to promoting substance diffusion involved in the simulation. The radiation effect should not be neglected. Oxygen-related parameters were secondary sensitive. The transformation of various forms of phosphorus was inseparable from the existence of DO. Redox environment directly affected the combination of metal ions with PO4-P. Anaerobic environment promoted the dissolution of insoluble PO4-P in sediment, and the PO4-P returned to the overlying water. However, the aerobic layer of sediment became a barrier which kept ions in an oxidized state, promoting the combination with PO4-P closer. Additionally, the physiological metabolic activities of benthic organisms and the toxicological characteristics of sediments were closely connected to the oxygen environment, and the changes of biological activities also indirectly affected the absorption of phosphorus by microorganisms. Compared with nitrogen, the change of redox environment at ‘sediment-water’ interface had a more prominent effect on phosphorus cycle. In addition, parameters related to temperature were particularly sensitive in the central, eastern, northwestern and southwestern lakes, where the eutrophication degree was relatively low and algae growth and microbial activity were weak.

4. Conclusions

The temporal and spatial distribution of PO4-P and TP in Lake Taihu was extremely uneven and the uncertainty of diagenesis model had a strong influence on the simulation of PO4-P and TP. For PO4-P, the wind and wave disturbance at the ‘sediment-water’ interface was heavier in shallower water region. Both water circulation in the bay area and low DO content were conducive to the release of dissolved phosphorus from the sediment. For TP, the contents of granular phosphorus and dissolved organic phosphorus in the central lake were greatly affected by the uncertainty of diagenesis model parameters. Sensitive parameters mainly consisted of two kinds of parameters related to oxygen and dynamic characteristics respectively.

5. Acknowledgement

The authors wish to express their great gratitude to the toolbox developed by Pianosi et al.

References:

1. Boudreau B P. The mathematics of early diagenesis: From worms to waves. Reviews of Geophysics. 2000, 38 (3): 389-416.

2. Choudhary S, A. K Tiwari, et al. Sedimentological and geochemical investigations to understand source of sediments and processes of recent past in Schirmacher Oasis, East Antarctica. Polar Science. 2018, 15: 87-98.

Uncertainty of Runoff Time Series at Multi-temporal Scales Yan Ye1,*, Jinping Zhang, Xunjian Long, Yong Ye, Lihua Ma 1 College of Resources and Environment * Correspondence: Yan Ye, [email protected]

Keywords: runoff; periodic fluctuation; empirical mode decomposition; set pair analysis; multi-temporal scales

1. Introduction

The runoff series exhibit highly complex uncertainty fluctuations in the long time scale， and the potential law of uncertainty is key to improving the prediction that impact human activities[1,2], and is crucial to efficient protection and utilization of water resources. The EMD and The SPA can be combined to accurately propose the uncertainty of runoff. Therefore, this study aims to detect the uncertainty of flood season, non-flood season, and annual runoff. The natural runoff time series from 1937-2006 of Zhangjiashan hydrological station (ZHS) on the Jinghe River of China are decomposed into multi-temporal scales with EMD to obtain fluctuation components with different periods. Then SPA method is applied to study the uncertainty of fluctuation components with different periods.

2. Methodology

Based on the local characteristic of local time domain of the data, Huang[3] proposed EMD which can decompose any nonlinear and nonstationary signal into a set of IMFs, that are amplitude and frequency modulated signals. SPA is a method used for the systematic analysis of certainty and uncertainty, as well as the certainty-uncertainty interaction between the two sets in a set pair within the background of a given problem. In general, the analysis is performed by establishing the connection for the two sets under consideration[4].The basic concepts of SPA include set pairs and their degree of connection. The common features (identical), contrary features (contrary), and features that are neither common nor contrary in the two sets (discrepancy) can be identified.

3. Results and Discussion

A quasi-periodic fluctuation of 2 to 5 years is presented in the IMF1 component. Except in the mid-1960s, a quasi-periodic fluctuation of 5 to 9 years is presented in the IMF2 component. A quasi-periodic fluctuation of 9 to 15 years is presented in the IMF3 component. In the IMF4 component, there are only two whole wavelengths in the time series, the quasi-periodic fluctuation of 23 to 27 years is presented. The residue component indicates the overall varying trend of the annual runoff. The SPA on runoff with multi- temporal scales reveals the relationships between the IMF components by identity, discrepancy, and contrary. 73

4. Conclusions

The fluctuation period in the IMF1 component and the IMF2 component maintains an excellent similarity with El Nino. This shows that there has been a close relationship between El Nino and runoff of the Jinghe River. Moreover, the IMF3 and IMF4 component may be related to the air-sea intersection and the long period of solar activity. It presents that the identity and discrepancy are the main two. Furthermore, it reveals that the connection degree of the flood season between annual runoff periods is the largest, and the connection degree of flood period between non-flood period is the smallest, which shows that the trend of the flood season is very similar to annual runoff, and the fluctuation period of the annual runoff can be reflected by the flood season series. So, the short and middle term forecast accuracy of runoff changes should be enhanced for the rational regulation and planning of Jinghe River water resources.

5. Acknowledgement

This research was supported by the National Natural Sciences Foundation of China (Project No. 41501288).

References

1. Syvitski JPM; Vorosmarty CJ; Kettner AJ; Green P. Impact of humans on the flux of terrestrial sediment to the Global Coastal Ocean. Science 2005,308(5720),376-380. PMID: 15831750

2. Wang S; Fu B; Piao S;Lü Y; Ciais P; Feng X et al. Reduced sediment transport in the Yellow River due to anthropogenic changes. Nat Geosci .2015,9(1),1-5

3. Huang, S. Z.; J. X. Chang; Q. Huang; and Y. T. Chen. Monthly streamflow prediction using modified EMD-basedsupport vector machine. J. Hydrol. 2014,511,764–775

4. Zhao K.Q. The application of SPA-based identica-ldiscrepancy-contrary system theory in artificial intelligence research. Trans Intell Syst.2007,2(5):20-35

Simulation of Hydraulic infrastructures in 2D High- Resolution Urban Flood Model Yunsong Cui1,*

1 Hohai University, Nanjing 210098, P.R.China * Correspondence: Yunsong Cui, [email protected]

Keywords: urban flood modeling; hydraulic structures; shock-capturing scheme; shallow water equations; GPUs.

1. Introduction

Urban flooding as a result of rapid catchment respond to intense rainfall, failure of flood defenses, etc. is usually featured with highly transient hydrodynamics. Reliable and efficient prediction and forecasting of these urban flash floods is still a great technical challenge. Meanwhile, in the urban environments, the development of a flood event may be predominantly influenced by flow-regulating and flood-protection hydraulic infrastructure systems such as dams, sluice gates and pump stations, which should be effectively taken into account in an urban flood model. However, direct simulation of hydraulic structures is not a current practice in 2D urban flood modelling. This work aims to develop a robust numerical approach to directly simulate the effects of gate and wall structures in a 2D high-resolution urban flood model. The resulting modelling tool allows us to efficiently evaluate the influence of certain key hydraulic infrastructure during an urban flood event. The adopted urban flood simulation model solves the full 2D shallow water equations using a finite volume Godunov-type shock-capturing numerical scheme, incorporating an HLLC approximate Riemann solver. The model is accelerated using multiple graphics processing units (GPUs) to enable computationally efficient large-scale urban flood modelling at high resolutions (e.g. ~2m spatial resolution across a city of ~1000 km2). New computational module is developed and fully coupled to the 2D model to directly simulate the highly transient flood waves through hydraulic structures. Different coupling approaches, e.g. flux and source term coupling, are implemented and compared in idealized cases. The enhanced urban flood modelling tool is applied to a realistic scenario of flood inundation over an urban area of 25.8km2 in Yuhuan city, Zhejiang province, China. Satisfactory results demonstrate that the present modelling approach is able to accurately simulate the flow through hydraulic structures and enhance the predictive capability of the 2D model for urban flood modelling.

Session 6: Hydro-environment Modelling II

A Study of Minimum Ecological Water Level of Lake Baiyangdian, North of China

Dan Liu1,*, Xuan Wang, Shengjun Yan, and Yunlong Zhang 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Dan Liu, [email protected]

Keywords: Minimum ecological water level; hydrological connectivity; water depth simulation

1. Introduction

As the largest wetland in North China, Lake Baiyangdian plays an important role in maintaining the ecological balance of this area, such as biodiversity conservation and climate regulation. Over the past years, however, its hydrological functions declined greatly due to decreasing ecological water resource with increasing human activities and climate changes. It is therefore essential to sustain the minimum ecological water level. In this study, a lake hydrological connectivity method was proposed to define the minimum ecological water level based on the objective of maintaining reasonable hydrological connectivity which is an important stability indicator of the pattern and function of wetlands. Using MIKE 21 software the water depth distribution was simulated, thus twenty images of the water boundaries and fine water patches were obtained within different lake levels. Using connectivity indices method, the corresponding lake hydrological connectivity was then evaluated, and the subsequent relationship of connectivity variation with water levels was analyzed. Thus, the minimum ecological water level was obtained as the breakpoint of the lake level-connectivity curve.

A 1D-2D Coupled Lattice Boltzmann model for Shallow Water Flows

Hongda Wang1,* 1 University of California, Davis * Correspondence: Hongda Wang, [email protected]

Keywords: lattice Boltzmann method; hydrodynamics; 1D-2D coupling; shallow water equations

1. Introduction

In this paper, a one- and two-dimensional (1D-2D) coupled scheme is proposed to solve the Shallow Water Equations (SWE) using the lattice Boltzmann method (LBM). The coupling approach adopts water velocity from the boundary of the 1D model and water depth from the 2D model, then applied as boundary conditions to each other. In addition, the zero-gradient boundary condition is applied to get the water velocity and depth from the adjacent lattice. According to the results of two benchmarks, the proposed scheme coupled the 1D and 2D LBM hydrodynamic models well, which keeps mass and momentum conservation for the coupling model. The coupling method has the potential to be used in other dimensional coupling using LBM.

Analysis of Water Quality Scenario Simulation in the Yellow River in Ningxia Section Based on EFDC

Di Liu1,*, Zhiming Zhang 1 1 School of Environmental and Energy Engineering, Beijing University Of Civil Engineering And Architecture, Beijing 100044, China * Correspondence: Di Liu, [email protected]

Keywords: EFDC model; Yellow River; water quality simulation

1. Introduction

With the rapid development of society, the population is increasing, and the water demand is increasing [1]. In addition, the lax management of waste water discharge has led to a series of water quality problems [2]. Therefore, water quality has become one of the most concerned topics in society. This paper takes the Yellow River in Ningxia Part as the research object, establishes the hydrodynamic and water quality model based on the EFDC model, sets different situations and analyzes the changes of water quality in the Ningxia section of the Yellow River. It provides reference for the pollution load distribution of pollution sources.

2. Methodology

The Environmental Fluid Dynamics Code (EFDC) is a comprehensive model developed by the Virginia institute of Marine science (VIMS) [1-7]. It includes hydrodynamic modules, water quality modules, and sediment modules that can be used to simulate various waters [1-7]. This paper uses hydrodynamic and water quality modules to build models. Two scenarios were designed with the flat water period as the boundary condition. Scenario 0: Basic scenario. Scenario 1: Interception of the tributaries of the Yellow River. Scenario 2: 50% reduction in pollution emissions from various sources. Observe the changes in water quality of the Yellow River under two scenarios.

3. Results and Discussion

In the flat water period, the concentration of pollutants in the lower reaches of the northeast is higher, mainly due to the dense population in the urban area. In addition, the large amount of pollutant emissions is not effectively degraded. After the closure of the tributaries of the Yellow River, the pollution discharge remains unchanged. At this time, some pollutants cannot enter the Yellow River system, and the water quality of the Yellow River has been improved. By cutting pollution sources by 50%, less pollution will be discharged and the water quality of the Yellow River will be improved.

4. Conclusions

Through the simulation of the model, it can be seen that both water conditions can improve the water quality of the Yellow River during the flat water period. On the whole, the 50% reduction in pollution source can improve the water quality of the entire Ningxia water system. Therefore, the pollution load distribution plan should be formulated according to actual demand.

5. Acknowledgement

The research was supported by the Environmental Protection Special Fund of Ningxia Hui Autonomous Region (Grants No. 201703).

References

1. He J.Y. Water environment simulation of three gorges reservoir area in chongqing based on the urban driving force of EFDC. Chongqing university,2018.

2. Yuan Y; Han L.X.; Sun Y, Chen Q.L.; Cheng L; Wang Y. Numerical simulation analysis of reservoir water quality response based on typical rainfall TN storage process. Journal of safety and environment,2014,14(03):189-193.

3. Xing Z.X.; Zhang L.H.; Ji Y; Li H. Study on water quality simulation and eutrophication evaluation of wudalianpool based on EFDC model. Journal of northeast agricultural university, 2008,49(05):88-98.

4. Zhang S. Research on water ecological environment analysis platform of great east lake water quality based on EFDC model. Huazhong university of science and technology,2017.

5. Song W.W.;,Xu Q.; Fu X.Q.; Wang C.F; Pang Y; Song D.H. EFDC simulation of fishway in the Diversion Dahaerteng River to Danghe Reservoir, China. Ecological Indicators,2019,102.

6. Ren L; Hu Z; Michael Hartnett. Prediction of coastal surface currents using numerical model and soft computing model. Energy Procedia, 2008,153.

7. He Q. Water quality scenario analysis of the main section of Yangtze river -- jialing river chongqing based on the coupling model of EFDC and WASP. Chinese society of environmental sciences.2014 academic annual meeting of Chinese society of environmental sciences (chapter 4).

Effects of Dam Regulation on the Hydrological Alteration and Morphological Evolution of the Volta River Delta

Mawusi Amenuvor1, Dongdong Shao1,*, and Weilun Gao1 1 State Key Laboratory of Water Environment Simulation & School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Dongdong Shao, [email protected]

Keywords: dam regulations; hydrological alteration; morphological evolution; Volta River Delta; Akosombo dam; Kpong dam

1. Introduction

Deltas are important to both human societies and coastal ecosystems. However, increasing anthropogenic activities, such as dam regulations, have affected the morphological evolution of deltas worldwide [1]. The Volta River, the main sediment source for the Volta River Delta (VRD), is greatly regulated by the Akosombo dam [2] and the Kpong dam, which leads to adverse effects on the morphological evolution of the Volta River Delta. Therefore, it has become necessary to investigate the extent of the impact of the dam regulations on the hydrological alterations and how the hydrological alterations subsequently influence the morphological evolution of VRD especially the delta area and shoreline changes.

2. Methodology

The research first analyzed the hydrological alteration using monthly and annual river and

sediment discharges (Qw and Qs respectively) from 1936 to 2018, which were obtained from the Volta River Authority of Ghana and Water Resources Institute of Ghana. The interannual variations for pre- and post- Akosombo dam were analyzed using simple regression and MK trend analysis. For intra-annual variations, the non-uniformity

coefficient (Cy) and the regulated coefficient (Cr) were determined for the pre- Akosombo (1936 to 1964), The pre-Kpong (1970 to 1982) and post- Kpong (1983-2018) dam to examine the impacts of dam regulation during different periods. Landsat remote sensing images of VRD were obtained from USGS from 1972 to 2018 to conduct the analysis of morphological evolution. The shoreline was extracted manually in ArcGIS 10.3. Delta area was further calculated after the extraction of the shoreline. The accretion-erosion rates were calculated and their relationship with the cumulative sediment load were also analyzed.

3. Results and Discussion

The average river discharge and sediment load for the pre-dam period were 1237 m3 /s and 5.9×105 m3 /d with a standard variation of 516.8 m3 /s and 2.48 ×105 m3 /d, respectively,

whereas those for the post-dam period were 949 m3 /s and 4.6×104 m3 /d with a standard variation of 196.1 m3 /s and 0.94×104 m3 /d, respectively. The nonuniformity coefficients of river discharge were 1.45, 0.07 and 0.09 for the periods of pre-Akosombo, pre-Kpong dam and post-Kpong dam, respectively. Whereas the regulated coefficients of river discharge for those periods were 0.55, 0.03 and 0.04, respectively. The nonuniformity coefficients of sediment load were 1.44, 0.04 and 0.09 for the periods of pre-Akosombo, pre-Kpong dam and post-Kpong dam, respectively. Whereas the regulated coefficients of sediment load for those periods were 0.55, 0.03 and 0.04, respectively. The construction of the Akosombo dam affects the intra-annual variation of river discharge more significantly than the Kpong dam. This study suggested that a more stable shoreline exists in the VRD with small fluctuations of erosion or accretion less than 0.56%. The relationship between cumulative sediment load and the changes of the delta area is weak.

4. Conclusions

The intra- and inter-annual hydrological variations are higher in the pre-dam construction period and relatively more sediment is impeded by the dams compared to river discharge. Impact of Akosombo dam is higher than that of Kpong dam. The, VRD underwent severe erosion before the 1970s due to the reduction of the sediment, however, the VRD has achieved an equilibrium state since 1970s. The VRD could stay in the equilibrium state as the sediment load is kept at the current level.

5. Acknowledgement

To the China Scholarship Council and Chinese Government whose sponsorship has made this work possible.

References

1. Syvitski JPM, Saito Y. Morphodynamics of deltas under the influence of humans. Glob Planet Change. 2007;57(3–4):261–82.

2. Ly CK. The role of the Akosombo Dam on the Volta river in causing coastal erosion in central and eastern Ghana (West Africa). Mar Geol. 1980;37(3–4):323–32.

Numerical Study of Hydrodynamics and Water Quality in Qinhuangdao Coastal Waters, China—A Well-known Region for Its Bathing Beaches

Wei Huang1,2, Wei Ma2, Jiquan Song1,3, Xiaobo Liu1,2,*, Wenqi Peng1,2 1 State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China 2 Department of Water Environment, China Institute of Water Resources and Hydropower Research, Beijing 100038, China 3 College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, Hubei, China * Correspondence: Xiaobo Liu, [email protected]

Keywords: Qinhuangdao coastal waters; water environment capacity; share ratio

1. Introduction

In recent years, the increasing discharge of pollutants into the ocean and coastal waters have become a great challenge for environmental protection worldwide, especially in China with its rapidly growing economy. A clear understanding of the temporal and spatial distribution of water quality in coastal waters is a prerequisite for evaluating the quality of the water environment in coastal waters, analyzing the sources of pollutants and improving the water environment in coastal waters. Traditional methods to investigate the spatiotemporal characteristics of water current and quality are based on in situ measurements. Although in situ measurements are accurate, they are usually very time- consuming and large-scale measurements incur substantial costs. With the development of science and technology, numerical simulations have been widely and successfully used as a tool for studying hydrodynamics and pollutant migration of coastal areas[1]. In this study, we investigated the hydrodynamic characteristics and spatio-temporal distribution of water quality based on a 2D model. The main rivers that need to regulated in order to control the pollutant flowing into Qinhuangdao coastal water were identified, the total water environment carrying capacity (WECC) computed, and environmental management guidance provided.

2. Methodology

The Qinhuangdao coastal waters are located in the Northwestern Bohai Sea, China .The MIKE 21 model is a widely used hydrodynamic model developed by the Danish Hydraulic Institute, this study uses MIKE21 software to establish water environment model of Qinhuangdao.

3. Results and Discussion

The higher flow velocity is located on the southwest and northeast sides of the study area, and lower flow velocity appears near the coastline. The flow velocity in Qinhuangdao coastal waters varied in the range 0–0.6 m/s, indicating that the area belongs to the weak tidal current area. Moreover, the tidal flow moves mainly in the coastal waters between the Luanhe and Shihe rivers, while the tide flows move outward to sea at a lower frequency, resulting in the water exchange capacity being relatively weak. COD transport and diffusion in the study area is relative week, because Bohai Bay has a weak water exchange capacity and it is difficult for terrestrial pollutants to diffuse outward. The weak diffusion leads to significant near-shore pollution and the pollutants from rivers entering into sea were the main contributor to the water quality. Because the worst water quality is at control point 2, WECC at point 2 can be used as the main control point for river pollution management. Given the water quality distribution of Qinhuangdao coastal waters, which has the best water quality in the northeast, followed by the southwestern coastal waters, with the worst being in the central coastal waters (Yinmahe river, Dongshage river, and Yanghe river estuary). Therefore, local water environmentalists should pay more attention to the pollution loads from the Yinmahe, Dongshahe, and Yanghe river.

4. Conclusions

In this study, we established a 2D numerical model based on the MIKE 21 module, and investigated the characteristics of hydrodynamics and water quality in the Qinhuangdao coastal area. The results indicate that the flow tides of the Qinhuangdao area are relatively weak, which makes it hard for pollution to diffuse. The water quality was found to be worse in the center area, and it was also found that more attention should be paid to the pollution loads from the rivers. The WECC of each river under two water quality levels (level I or level II) were calculated, the results indicated that the WECC of the Qinhuangdao area is enough for the present pollution load, and the rivers that should be monitored have been identified.

5. Acknowledgement

Many thanks to the two anonymous reviewers, whose insights and valuable suggestions helped to significantly improve this manuscript. We also thank QinHuangDao Water Authority for providing the monitoring data for modeling.

References

1. Xu, J.; Li, Y.; Huang, G. A Hybrid Interval-Robust Optimization Model for Water Quality Management. Environ. Eng. Sci. 2013, 30, 248–263.

Temporal Changes of Baseflow and Its Implication for Environmental Flow Xiaojing Ma1,3, Qiang Liu1,2,*, Jihua Pan3, and Jingling Liu1,2 1 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China 2 Key Laboratory for Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China 3 School of Geography and Tourism, Qufu Normal University, Rizhao 276826, Shandong, China * Correspondence: Xiaojing Ma, [email protected]

Keywords: baseflow; ABIT; regression constant; chapman-Maxwell method; Taoer river

1. Introduction

Baseflow is important for maintaining the baseflow and ecosystem health of the river streamflow during dry season [1]. The process of subdividing baseflow is an important theoretical basis for understanding the contribution of groundwater to streamflow process and calculating river ecological discharge. Digital filtering is widely used in base-flow segmentation because of its stable and accurate results [2]. However, the digital filtering method of the Ressgion constant lack of physical meanings and sensitive to the start point of baseflow separation.so this study improved the Ressgion constant, and used the Taoer River as the research object to analyze the variation law of the baseflow.

2. Methodology

Based on the daily streamflow data and isotope data of the Taonan Hydrological Station, in the Taoer River Basin, by the Automatic Baseflow Identification Technique (ABIT) [3] improved the Ressgion constant, and then the Chapman-Maxwell method is used to baseflow separation in Taoer River. The isotope analysis was carried out on the data collected in the wilderness of the Taoer River Basin, for obtaining the measured the baseflow contribution to streamflow The accuracy of the improved Chapman-Maxwell was verified by the measured results.

3. Results and Discussion

The baseflow were separated from the streamflow used the Regression constant obtained from ABIT. As the result showed, the Regression constant of Taoer River is 0.9838. And the baseflow contribution to streamflow is 37.73% in Taoer River Basin, which is consistent with results obtained from the Isotope Analysis method.

Annual baseflow ranged from 3.07×104 m3/s to 0 m3/s (1960 to 2016). According to linear fitted model, annual baseflow presented a decreased trend with an average slope of -76.24 (m3/s)/a.

During the non-flood period and the flood season of the Taoer River, the baseflow contribution to streamflow is 66.2% and 37.5%, respectively. The results indicated that the streamflow stability component increases and the positive factor of maintaining the balance of river ecosystem increases; the flood pulse contribution to streamflow is larger, a large contribution means an increase in streamflow instability and increased negative factors in maintaining river ecological balance.

4. Conclusions

It’s found that Chapman-Maxwell method presented a suitable result in separating the baseflow from the streamflow compared with actual baseflow identified by the Isotope Analysis method, when the regression constant is 0.9838. Decreasing trends of the baseflow in Taoer River were detected. The contribution of the baseflow to the streamflow is reduced. In different temporal scale, the baseflow contributed magnitude for changes in streamflow. All of these results indicated that baseflow should be play an important role in maintain the environmental flow especially in the dry regions or seasons.

5. Acknowledgement

This study was supported by the National Key R&D Program of China (No. 2016YFC0500402), and the National Natural Science Foundation of China (No. 51579008).

References:

1. Fan, Y.T., Chen, Y.N., Liu, Y.B., Li, W.H. Variation of baseflows in the headstreams of the Tarim River Basin during 1960–2007. Journal of Hydrology, 2013, 487: 98-108.

2. Gonzales, A.L., Nonner, J., Heijkers, J., Uhlenbrook, S. Comparison of different base flow separation methods in a lowland catchment. Hydrological Earth System Sciences, 2009, 13(11): 2055-2068.

3. Cheng, L., Zhang, L., Brutsaert, W. Automated selection of pure base flows from regular daily streamflow data:Objective algorithm. Journal of Hydrologic Engineering. 2016, 21(11): 0601-0608.

Session 7: Water Management Modelling

Urban Fluvial Flood Modelling Study

Min Li1,* 1 China institute of water resources and hydropower research, Beijing 100875, China * Correspondence: Min Li, [email protected]

Keywords: urban pluvial flood model; runoff generation; overland flow; pipe network flow; river network flow

1. Introduction

With the increase in frequency of flood events induced by intense rainfalls in urban areas, people living in those areas are exposed to high risk levels of pluvial flooding. The numerical model can provide technical support for urban flood risk management. In order to meet different requirements on accuracy and computational demands, two pluvial flood models, i.e., the coarse model and the refined model, are built for an urban area in Shenzhen. The coarse model is quite simplified on physics, while the refined one is a holistic model, which is capable of simulating processes including runoff generation, overland flow, river network flow and pipe network flow. The advantages and disadvantages of the two models are discussed.

Experimental Investigation of Air Entrainment in a Submerged Plunging Dropshaft

Kam C.H. Chiu1, S. N. Chan1,2,* 1 Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China 2 Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong, China * Correspondence: S.N. Chan, [email protected]

Keywords: plunging intake; dropshaft; air entrainment; air volume fraction; air-water flow; urban drainage system

1. Introduction

Air entrainment is important for the design of urban drainage systems. When water flows into a submerged vertical dropshaft, the impact of falling water on the free surface can entrain a vast amount of air to form a column of air-water “emulsion” in the dropshaft. For the first time, the air volume fraction profile for a submerged plunging dropshaft is measured to study its air entrainment characteristics.

2. Experiments

In the experimental set-up, the water flows to the plunging intake, then through a submerged vertical dropshaft of 0.069m diameter down to a tunnel of 0.12m diameter (Fig. 1a). The tunnel is connected to a head tank downstream to create the dropshaft submergence. The vertical air volume fraction profile in the submerged dropshaft is measured using a single-tip conductivity probe installed at the centerline of the dropshaft, with its vertical position adjustable. The probe is connected to a bridge box and a strainmeter to provide alternate current (AC) excitation. The probe detects the phase change by the voltage difference between water (0V) and air (3.5V), as air bubbles pass through its tip. Besides, two pressure transducers are installed at 0.47m and 0.94m above the bottom of the dropshaft for simultaneous pressure measurement. The conductivity probe and transducers are connected to a data logger to record the voltage with frequency of 10 kHz. The free surface of the aeration column is also recorded.

3. Results and Discussion

The free surface of the aerated water column increases slowly when the flow increase from 21 to 26 L/min, but increase much more rapidly when the flow increases beyond 26 L/min, indicating a net air transport down the dropshaft. The average air volume fraction between the free surface and the pressure transducer can be estimated from the measured pressure based on a control volume approach.

The measured voltage by conductivity probe is log-normally distributed. The air-water discriminating criteria is calibrated using the average volume fraction estimated from pressure measurement. The criteria of 0.5V for demarcating air and water shows a good match with the average volume fraction estimated from pressure measurement. It shows that air volume fraction is approximately constant for the upper aerated part of the water column, about 0.15-0.2 for all the flow measured. At the lower unaerated part of the water column, the concentration drops to zero quickly (Fig. 1b).

4. Conclusions

Experiments are carried out to study air entrainment characteristic for a submerged vertical plunging dropshaft. A conductivity probe for measurement air volume fraction is calibrated against the bulk air volume fraction estimated from fixed-point pressure measurement. Air volume fraction is found approximately constant at 0.15-0.2 for the aerated part of the water column.

(a) (b)

Figure 1: (a) A three-dimensional view of the experiment setup, (b) Volume fraction verse height from the free surface for Q = 25 and 26.5 L/min.

Acknowledgement

This study is supported by the Initiation Grant (IGN17EG05) and the Undergraduate Research Opportunities Program (UROP) of HKUST.

Numerical Study of Environmental Characteristics and Ecological Water Supplement of Caohai Lake in Guizhou Province

Wei Huang1,*, Chenguang Xiang1, Xiaobo Liu1, Huihuang Luo1 1 China Institute of Water Resources and Hydropower Research, Beijing 100038, China * Correspondence: Wei Huang, [email protected]

Keywords: Caohai Lake; water environment; numerical simulation; water supplement

1. Introduction

In the lake ecosystem, the water environment condition of the lake plays a vital role in the whole ecosystem. In recent years, due to the influence of human activities, the problem of eutrophication caused by lake pollution has become the main ecological and environmental problem facing the world today. Transferring water from other clean water bodies to polluted lakes is an effective and widely used method to alleviate water quality deterioration. A large amount of water with low nutrition is transferred to the eutrophic lake to dilute the polluted water body, and at the same time the water environmental capacity of the lake is increased, thus reducing the nutrient concentration of the lake. After pollutants enter the water body, they will undergo processes such as migration, mixing, decomposition, dilution and degradation, the establishment of a mathematical model of the water environment can determine these mutually restricting relationships and provide a basis for the planning and management of the water environment. Water environment model is an important tool to identify water environment problems and study corresponding solutions, it can reveal water environment problems concisely and intuitively[1]. Caohai Lake, located in Weining county, Guizhou province, is one of China's three famous plateau lakes and one of the eight bird reserves. In recent years, water quality of Caohai Lake has shown an obvious deterioration trend, causing eutrophication of water bodies. Therefore, based on MIKE21 software, this paper established a water environment model of Caohai Lake to simulate and analyze the spatial-temporal water environment and the improvement effect of ecological water replenishment on the water quality, so as to provide scientific basis for comprehensive management of Caohai Lake.

2. Methodology

Caohai Lake is a typical shallow water lake, so it is suitable to use the shallow water equation to build the model. In this study, the MIKE21 module of the MIKE software developed by the institute of water resources and water environment in Denmark was selected to build the water environment model of the Caohai Lake.

3. Results and Discussion

The self-purification capacity is weak in dry years, and the amount of pollution entering the lake is large in wet years, resulting in the concentration of each water quality indexes is shown as dry year > wet year > normal year. The annual change of concentration of COD showed a trend of basically maintaining the same at first and then gradually decreasing, the concentration of NH3-N, TN and TP all showed a trend of first falling, then rising and then falling, the fluctuation of water quality concentration mainly depends on the leading role of the amount of pollution entering the lake and the self-purification capacity. Caohai Lake is affected by rivers entering the lake, and the concentration of water quality indexes shows obvious spatial difference, which is shown as a decreasing trend from east to west, and the high concentration was concentrated in the lake-entering areas in the northeast and west. After replenishing water, the average concentration of COD decreased by 6.1~7.2mg/l and the removal rate was 30%~34%, the average concentration of NH3-N decreased by 0.49~0.52mg/l and the removal rate was 73%~74%, the average concentration of TN decreased by 0.06~0.07mg/l and the removal rate was 47%~48%, the average concentration of TP decreased by 0.63~0.68mg/l and the removal rate was 53%~57%.

4. Conclusions

The spatial distribution of water quality concentration of Caohai Lake shows a decreasing trend from east to west. The interannual variation of the concentration of each index was shown as dry year > wet year > normal year, the annual change of concentration of COD showed a trend of basically maintaining the same at first and then gradually decreasing, the concentration of NH3-N, TN and TP all showed a trend of first falling, then rising and then falling. After replenishing water, the quality concentration of each water quality index in Caohai decreased by one grade, and the improvement effect of water quality is shown as dry year > normal year > wet year.

5. Acknowledgement

The research is supported by the basic scientific research project of the China Institute of Water Resources and Hydropower Research (Grants No.0145B782017, Grants No. 0145B342016).

References

1. Xu, J.; Li, Y.; Huang, G. A Hybrid Interval-Robust Optimization Model for Water Quality Management. Environ. Eng. Sci. 2013, 30, 248–263.

Study on Locating Warning Stations for Drinking Water Sources Safety at Tidal Reaches

Hongwei Ding1,*, Zhenshan Xu1, Yongping Chen1, and Shiqiang Lu2 1 College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing 210024, China 2 Shanghai Academy of Environmental Sciences, Shanghai 200233, China * Correspondence: Hongwei Ding, dhwhhu@ hhu. edu. cn

Keywords: accidental water pollution; drinking water source; Delft3D; warning station

1. Introduction

Accidental water pollution events occur frequently as a result of the accelerated process of industrialization and urbanization in some countries, especially in China and other developing countries [1]. Thus, the safety of drinking water sources, which is of great importance for the healthy life of human, might be threatened by the accidental leakage incidents arisen from port handling operation or shipwreck. Warning Stations near water sources could guide the water intaking operation during those incidents [2] and their location-selecting is subjected by the efficiency of emergency response as well as local hydrodynamics (namely the upstream discharge and tidal forces). In this study, a two- dimensional hydrodynamic and phenol model is developed using Delft3D software, aiming to determine the location of warning stations for drinking water sources (Changqingsha and Langshan) at Chengtong Reach, a tidal reach of Yangtze River.

2. Methodology

The two-dimensional numerical model at Chengtong Reach integrated hydrodynamic and water quality processes, and was developed using Delft3D-FLOW and Delft3D-WAQ modules. Delft3D-FLOW module provided the flow field information for the water quality model. The water quality model developed by Delft3D-WAQ module solved advection - diffusion-reaction equation in two dimensions for the target contaminant (phenol). The resolution of horizontal grid in Chengtong Reach is around 300m×600m. Based on the historical data, twelve typical abrupt leakage incidents were supposed to take place along the lower Yangtze River. The simulated temporal and spatial phenol concentration fields were analyzed overall to reveal the feature of contaminant transport at the tidal reach.

3. Results and Discussion

In this paper, the hydrodynamic model was validated against the field data, while the water quality model was calibrated using the measured phenol concentration at Chengtong Reach during the phenol leakage incident in Zhenjiang [3]. A series of typical numerical experiments illustrated that the pollutants from the left bank are more dangerous than those from the right bank for Changqingsha water source, and upstream 93

contaminant tended to be transported to the left bank, where Langshan intake is located, because of the flow coming into the main channel. This would result in more dangers than Changqingsha intake, although the contaminant concentration around Langshan water source is relatively low.

4. Conclusions

On the basic of typical numerical experiments, two groups of warning stations were determined at the upstream and downstream of Changqingsha and Langshan respectively, as shown in Fig.1. They would provide at least one hour warning time for the two water sources. The upcoming study would focus on the correlation between upstream discharge and the warning time.

Upstream Warning Station

Changqingsha Upstream Warning Station

Downstream Warning Station Langshan

Downstream Warning Station

Fig.1 Layout of Warning Stations at Nantong Reach

5. Acknowledgement

The study is financially supported by the National Key R&D Program of China (2017YFC0405401), and the Water Conservancy Science and Technology Project of Jiangsu Province (2017048).

References

1. Wang Y, Engel B A, Huang P, et al. Accurately early warning to water quality pollutant risk by mobile model system with optimization technology[J]. Journal of Environmental Management, 2018, 208: 122-133.

2. Sim H P, Burn D H, Tolson B A. Probabilistic design of a riverine early warning source water monitoring system[J]. Canadian Journal of Civil Engineering, 2009, 36(6): 1095- 1106.

3. Ding H W, Xu Z S, Chen Y P (2019). Modelling of Accidental Water Pollution Incidentsat Chengtong Reach of Yangtze River. Proc 29th Int Offshore and Polar Eng Conf, Hawaii, ISOPE. (in press)

Evaluation of Water Resources Carrying Capacity in the Yangtze River Delta Region Based on Factor Index Method

Qirui Xue1, Xiaohua Yang2,* 1 School of environment, Beijing Normal University, Beijing 100875, China 2 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Xiaohua Yang, [email protected]

Keywords: Yangtze river delta region; water resources carrying capacity; factor index method; spatial correlation

1. Introduction

The evaluation model of factor index method was established based on industrial wastewater discharge and the average value of the industrial wastewater discharge in the Yangtze river delta region. The water resource carrying capacity of 26 cities in the region was evaluated, and the spatial correlation analysis of the carrying capacity value was carried out. The results show that (1) in the Yangtze river delta region, 14 cities had continuous high water resources carrying capacity from 2006 to 2016, while Shanghai, hangzhou and suzhou had continuous poor water resources carrying capacity, and the remaining 9 cities had average water resources carrying capacity. (2) the variation range of water resources carrying capacity of each city was stable from 2006 to 2016. (3) the carrying capacity of water resources in the Yangtze river delta decreases from west to east. (4) the water resource carrying capacity of cities in the Yangtze river delta region has spatial correlation.

Assessing the Impact of the Three Gorges Reservoir on Eco-hydrological Regimes in the Dongting Lake, China

Hongxiang Wang1,* 1 Water resources school, China * Correspondence: Hongxiang Wang, [email protected]

Keywords: Three Gorges Reservoir; Dongting Lake; eco-hydrological regime; hydrological alteration degree; ecological effects

1. Introduction

Water level is considered as the key factor affecting the structure and function of wetland ecosystem. To assess the alteration of the eco-hydrological regimes in the Dongting Lake after the impoundment of the Three Gorges Reservoir, the change characteristics of water level regime were evaluated by using the Mann-Kendall statistical test, the cumulative anomaly and slide T detected method based on daily water level series at the Chenglingji, Nanzui and Yangliutan gauge station from 1959 to 2016, while the degree of alteration of the hydrologic regime and the ecological effect of the Three Gorges reservoir on the variation of 32 hydrological indices were also analysed by the range of variability approach and the hydrologic regime alteration degree method. The results show that the annual average water level of the Dongting Lake has shown a upward trend from 1959 to 2016. The Chenglingji gauge station has an obvious upward degree with the confidence degree of 95%, Nanzui gauge station has an obvious decrease with a confidence level of 95%, while the upward trends of the Yangliutan gauge stations are not significant. The abrupt change of annual average water level occurred in the year 2003, which reflects the significant effect of the Three Gorges Reservoir on the water level regime. The overall degree of hydrological alteration is moderate. The alteration degrees of the Chenglingji, Nanzui and Yangliutan gauge stations are 56%, 45% and 50%, respectively. The Three Gorges reservoir has caused alteration of the water level regime of the Dongting Lake, and altered water level regimes have influenced river habitat alteration, aquatic biodiversity decreases and fish population structure alteration. The study provides a scientific reference for the ecological protection and sustainable utilization of water resources in the Dongting Lake.

Session 8: Marine Ranching Study

Application of Stable Isotope Technology in Modern Marine Ranching

Shanshan Ge1, Jingjing Song1, Daode Yu1,* 1 Marine Biology Institute of Shandong Province，Qingdao 266104 * Correspondence: Daode Yu, [email protected]

Keywords: stable isotope; marine ranching; trophic niche

1. Introduction

Stable isotopes are elemental forms with the same number of protons, different numbers of neutrons and no radioactivity. Stable isotope technology has many advantages, such as tracing, integration and indication, rapid detection and accurate results, which have increasingly highlighted broad application prospects in ecology research. Xiaoheishan Island lies on the dividing line of the Yellow Sea and the Bohai Sea in China. In order to restore fishery resources, 220 hollow steres artificial reefs were built in the northeast sea area of Xiaoheishan Island in June 2014. In this present study, Sebastes schlegelii and Hexagrammos otakii were taken as the research objects. The trophic niches and overlap of two species of fish were analyzed by carbon and nitrogen stable isotopes.

2. Methodology Each fish species choosed thirty samples which were healthy and active from ground cages in Spring and Autumn . Muscle tissue was extracted from each sample and then dried and ground. Determine the values of δ13C and δ15N by stable isotope mass spectrometry on-line, and then carry out data analysis. The most commonly used analysis tool is the R language. Take carbon isotopes as an example. 1312 R/（ CC）sample δ13C=-1×1000 （1312 ） R/CCVPDB 13 12 In the formula, R( C/ C)VPDB is the carbon isotope abundance ratio of the international standard substance (PDB).

3. Results and Discussion

This study analyzed the niche overlap and wide variation between two typical reef fish species, S.schlegelii and H.otakii, from an artificial reef area of Xiaoheishan Island, during spring and autumn. The δ13C value of S. schlegelii was significantly higher than that of H. otakii in spring, while there was no difference between the two species in autumn. Moreover, the δ15N value of S. schlegelii was significantly greater than that of H. otakii in both spring and autumn. The frequency distribution of S. schlegelii δ13C values was always greater than that of H. otakii, while the seasonal variation of the δ15N frequency distribution was less than that of H. otakii. We concluded that S. schlegelii utilized a wide range of food sources and occupied a stable trophic level, while H. otakii had a narrower preference for food, and the trophic level it occupied fluctuates dramatically. In addition, there was an 98

overlap of trophic niches between the two species only in autumn, while at other times S. schlegelii had a higher and wider trophic niche than H. otakii. In conclusion, we found there was interspecific competition between S. schlegelii and H. otakii in the artificial reef community, and S. schlegelii had a superior ability to utilize food resources.

4. Conclusions

According to the current research results, the value of δ 13C can be used to judge the energy sources of different populations in the same space-time food web, and the value of δ 15N can be used to determine the nutritional position of the population in the food web. The two-dimensional C-N map can indicate the nutritional niche distribution of each population in the community. The use of stable isotope technology can not only support the research results of existing scholars, but also accurately indicate and correct the depth of conclusions. In the future, it will become an indispensable technology in the study of modern marine ranches.

Numerical Analysis of the Flows around Fishing Plane Nets Using Lattice Boltzmann Methods

Gangqin Tu1,*, Haifei Liu1 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Gangqin Tu, [email protected]

Keywords: Lattice Boltzmann method; Flow field; Flow-velocity reduction; Numerical simulation; Fishing plane net

1. Introduction

Flow through and around fishing net structures is an important issue in aquaculture. In this study, a three-dimensional numerical model is established to simulate the flow field around a plane net in steady current, using multi-relaxation time (MRT) lattice Boltzmann method. The plane net was represented by a number of columns. In order to validate the numerical model, the physical model experiments using plane nets were conducted in a flume. And it was found that the simulated results were in good agreement with the experimental data. The mean relative error of the flow velocity is about 4%. Based on this method, the velocity reduction factor of a plane net with different attack angles has been calculated. The results show that the numerical approach is applicable and reliable to investigate the flow field around a fishing net.

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Hydrodynamic Driving Mechanism and Process Simulation of Typical Biocompatible Habitat Pattern Changes in Estuary

Tao Sun1,*, Qianzhao Sun2 1 School of Environment, Beijing Normal University, Beijing 100875, China 2 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Tao Sun, [email protected]

Keywords: Laizhou Bay; Habitat Suitability Index; Fuzzy logic

1. Introduction

Nearshore estuarine serve as an important ecosystem to hold many kinds of function such as, fish and invertebrates diversity maintenance and support high primary and secondary productivity. As one of the indicator species in the Laizhou Bay, charybdis japonica play a vital role in mariculture, which may reveal the biological resources situation in yellow sea and bohai sea. A hydrodynamic model based on the measured and generalized data are used to simulate the water level, water temperature and salinity in Laizhou Bay during the charybdis japonica critical period. Then used these data as input data to input in the HSI model to obtain the charybdis japonica suitable habitat distribution. HSI model using fuzzy logic technology based on analyze inaccurate data based on expert knowledge. The result can provide a hydrodynamic basis for offshore aquaculture to use resources rational.

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Parameterization and Application of Dynamic Energy Budget Model to Hexagrammos Otakii

Yanyu Li1, Jianfeng Feng1,*, Lin Zhu1 1 The Key Laboratory of Pollution Process and Environmental Criteria of Ministry of Education and Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China * Correspondence: Jianfeng Feng, [email protected]

Keywords: hexagrammos otakii; dynamic energy budget model; parameterisation; DEB model;

1. Introduction

Hexagrammos otakii, which is a benthic species in the family Hexagrammidae, is commonly found in coastal areas throughout the year in Shandong offshore area and is a favorite seawater food fish due to its taste and tender meat. [1]. In recent years, with the increase in the intensity of coastal fishing, the catch of the H.otakii has been sharply reduced, and the phenomenon of resource decline has become increasingly serious. [2]. Consequently, developing an integrative model to describe the H.otakii life cycle in terms of energy allocation to diﬀerent physiological processes play important roles in predicting their ability to grow, reproduce and survive in a variable environment. [3]. The DEB model covers the full life-cycle of the animal from the start of development until death by aging. [4]. The aim of this study was to provide DEB parameters that best describes energy allocation over time of H.otakii using literature-based data.

2. Methodology

Data have been extracted from the literature, mainly including multiple observations over time (so-called univariate data) and observations for one time point (zero-variate data). Univariate data consisted of: 1) length/weight relationship, 2) hatching times at diﬀerent temperatures, 3) growth over time was included for the embryonic stage as well as the late juvenile and early adult stages, 4) oxygenconsumption as a function of length as well as temperature was included. Zero-variate data, which comprise of single data points, regarding age, length and wet weight at hatch, birth, metamorphosis, puberty and ultimate size were included. The above described data were used for the parametrization of the H.otakii DEB model with metabolic acceleration between birth and puberty. Parameter estimates were performed using freely downloadable software DEBtool (http://www.bio.vu.nl/thb/deb/).

3. Results and Discussion

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Using data from the literature and default estimation procedure from the DEBtool, DEB parameters for Hexagrammos otakii are presented. No data was available regarding when Hexagrammos otakii's metabolism stops accelerating. However, the combination of both embryo and adult data, provides enough information to estimate metabolic acceleration in H. otakii. Using the DEBtool parameter estimation routines, we were therefore able to estimate the maturity level at metamorphosis.

4. Conclusions

We present here a detailed model of energy allocation for Hexagrammos otakii based on the DEB theory. The energy-based framework of the DEB theory is able to quantify processes such as growth and feeding throughout the life cycle of an organism as a function of constant parameters and under changing environmental conditions. The dynamic nature of the model developed here allows the prediction of growth and assessment of the ecological carrying capacity of marine pastures.

5. Acknowledgement

This work is supported by the National Key R&D Program of China (2018YFC1406403).

References

1. Park.; In-Seok.; Kim. Evaluation of a Visible Implant Fluorescent Elastomer Tag in the Greenling Hexagrammos otakii. Fisheries and Aquatic Sciences. 2013, 16, 35-39.

2. Hu, F.; Pan, L.; Gao, F. Effect of temperature on incubation period and hatching success of fat greenling (Hexagrammos otakii Jordan & Starks) eggs. Aquaculture. Research. Aquac. Res. 2017, 48, 361-365.

3. Augustine, S.; Gagnaire, B.; Adam-Guillermin, C.; Kooijman, S.A.L.M. Eﬀects of uranium on the metabolism of zebraﬁsh, Danio rerio. Aquat. Toxicol. 2012, 118-119, 9- 26.

4. Kooijman, S.A.L.M.; Lika, K. Comparative energetics of the 5 ﬁsh classes on the basis of dynamic energy budgets. J. Sea. Res. 94, 19-28.

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Modeling the Spatial Distribution of Reef Fish Populations around an Artificial Reef-field：Based on a Trade-off between Foraging Success and Predation Risk

Yue Zhang1, Tao Sun2,* 1 School of Environment, Beijing Normal University, Beijing 100875, China 2 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Tao Sun, [email protected]

Keywords: artificial reef spacing; reef fish; population distribution dynamics; trade-off; density-dependent

1. Introduction

In the construction of Marine Ranching, how to optimize the configuration of artificial reef field is an essential issue for populations protection and habitat restoration. Previous studies have provided useful information about the influence of reef size, number and spacing on the spatial distribution of reef fish through the field observation or trap experiment, yet reef fish population spatial distribution mechanisms, especially the effects of prey resources and refuge provided by reefs, are not yet fully understood. An individual-based model was developed and applied to examine the relationship between reef deployment and fish population dynamics represented by distribution of fish abundance and biomass. The model simulated the growth，mortality and movement of Hexagrammos otakii, a typical reef fish in near shore area, and concerned the trade-off between predation risk and foraging success under different reef spacing. Then we explored the interaction among spacing of reefs and density-dependent competition for resources and predation risk. The study highlights the importance of spatial dynamic distribution of fish in designing the layout of artificial reefs.

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The Changing Characteristics and Driving Factors of Marine Fishery Resources in China

Wei Yang1, Ziyue Zhang1,*, Haifei Liu1, and Tao Sun1 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Ziyue Zhang, [email protected]

Keywords: fishery resources, anthropic factors, environmental factors, convergent cross mapping, structural equation models

1. Introduction

China is rich in fishery resources and has large sea areas, the Yellow Sea, the East China Sea and the South China Sea. So far, China is the world's largest producer of marine catches, but the amount of fishery resources continues to decline, with smaller individuals. In the face of increasing fishing pressure and climate change, the changes in fishery resources in China's four maritime zones and their driving reasons remain unclear. Based on long-term fishery statistics data, this study analyzed the changes of fishery resources, environmental factors, anthropic factors and disaster factors in China in a long time series, and identified the main driving factors affecting fishery resources through causal analysis. The causal relationship and the influence degree of different factors in different sea areas were found by convergence cross mapping (CCM), and the change model of fishery resources under the influence of multiple factors was constructed by structural equation model (SEM). This will help managers to find the focus of the management of fishery resources and Marine environmental governance, and provide a research foundation for sustainable development of fishery in the context of environmental changes and increasing external environmental changes caused by human activities.

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Others

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A Three-stage Hybrid Model for Spatial and Temporal Analysis of Water Resources Carrying Capacity in Jilin Province

Tong Liu1, Xiaohua Yang1,*, Yukun Luo1, and Boyang Sun1

1 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Xiaohua Yang, [email protected]

Keywords: water resources carrying capacity; evaluation; prediction; regulation; Jilin Province

1. Introduction

As one of the most important natural resources, water resources play an important role in the development of human society. With the rapid progress of regional urbanization and rapid economic development, water security has become an important part of urban safety [1]. Due to the uneven distribution of water resources in time and space, water scarcity exists in many provinces in China [2]. Jilin Province is located in the core area of Northeast China. The sustainable development of its water resources system is an important part of the national strategy of revitalizing the old industrial bases in Northeast China. Therefore, it is of great practical significance to study the water resources carrying capacity of Jilin Province. A three-stage hybrid model is used for spatial and temporal analysis of water resources carrying capacity in Jilin Province.

2. Methodology

In order to comprehensively analyze the water resources carrying capacity of Jilin Province, we established a three-stage hybrid model, which includes water resources carrying capacity evaluation, prediction and regulation. Stage I introduces the Logistic equation into the fuzzy comprehensive method, and the Logistic fuzzy comprehensive evaluation model is established to evaluate the water resources carrying capacity of Jilin Province. Stage II uses the system dynamics method to predict the water resources carrying capacity of Jilin Province. Based on the evaluation and prediction results, Stage III uses the system dynamics method to carry out intra-regional regulation and cross-regional regulation of water resources systems in cities in Jilin Province to achieve sustainable development of regional water resources systems.

3. Results and Discussion

There is a significant difference in the spatial carrying capacity of water resources in Jilin Province, which is generally better in the east than in the west. Changchun City, Baishan City, Songyuan City, Baicheng City, Yanbian Korean Autonomous Prefecture will have

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water shortages in the future. In order to alleviate the water crisis in the above-mentioned regions, we can start from two aspects. First, eliminate or transfer high-water consumption and low value-added enterprises to improve water use efficiency; second, transfer water from other cities. Jilin City, Siping City, Liaoyuan City, and Tonghua City have good water carrying capacity, and can supply water resources to other cities and states or accept transfer enterprises from other cities and states.

For Changchun City, Baicheng City and Songyuan City, it is necessary to improve the efficiency of agricultural water use and increase the water intake of the Songhua River to resolve its water shortage crisis. Through the Songhua River, the surplus water resources of Jilin City and Tonghua City are transported to the downstream water-deficient areas. Baishan City and Yanbian Korean Autonomous Prefecture need only slightly increase the utilization rate of water resources for future water demand.

4. Conclusions

This study establishes a three-stage hybrid model from the evaluation, prediction and regulation of water resources carrying capacity, based on the evaluation and prediction results, analyzes the main reasons for the overload of water resources carrying capacity, and regulates the water resources system to improve the water resources carrying capacity of Jilin Province. A set of solutions is provided.

5. Acknowledgement

This research was supported by the National Key Research Program of China (No. 2016YFC0401305，2017YFC0506603), the State Key Program of National Natural Science of China (No. 41530635), and the Project of National Natural Foundation of China (No. 51679007, 51379013).

References

1. Nazemi, A.; Madani, K. Urban water security: Emerging discussion and remaining challenges. Sustainable Cities and Society, 2017, 41, 925-928.

2. Jinxia, W.; Yanrong, L.; Jikun, H.; Growing water scarcity, food security and government responses in China. Global Food Security-Agriculture Policy Economics and Environment, 2017, 14, 9-17.

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Analysis of Water Use Efficiency in 31 Provinces and Cities of China in 2017

Boyang Sun 1, Xiaohua Yang1,* 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Xiaohua Yang, [email protected]

Keywords: DEA method; Water use efficiency; Input-output analysis

1. Introduction

China's water shortage and water pollution problems have existed for a long time. Due to the excessive development of water resources and the unreasonable industrial structure, the contradiction between supply and demand of water resources has become more prominent. China has a vast territory, but the distribution of water resources is uneven, and the economic development of various provinces and cities is uneven. In order to evaluate and compare the status quo of water resources in various provinces and cities in China, it is necessary to analyze the water use efficiency of various provinces and cities. This study uses multi-modal DEA analysis method to calculate and evaluate the water use efficiency of China's provinces and cities in 2017. The evaluation results can provide decision support for China's efficient use of water resources and water resources carrying capacity [1,2].

2. Methodology

Data Envelopment Analysis is a multi-factor productivity efficiency evaluation method, which is firstly proposed by Charnes A, Cooper W, and Rhodes E in 1978. The principle of this method is to treat each object of evaluation as a decision-making unit (DMU), keep the output or input of DMU unchanged, and determine the relatively effective production frontier, and then project each DMU onto the production frontier, and their relative efficiency is evaluated by comparing the deviation from the DEA production frontier[3].

3. Results and Discussion

Through the screening of indicators, the results of the water use efficiency of 31 provinces and cities obtained by constructing the DEA water use efficiency measurement model..According to the calculation results, the water use efficiency of 31 provinces and cities can be divided into three categories according to the returns to scale. The water use efficiency of Beijing, Guangdong, Guizhou, Hainan, Heilongjiang, Hubei, Jiangsu, Ningxia, Qinghai, Shandong, Shaanxi, Shanghai, Tianjin, Tibet, Zhejiang and Chongqing has reached a relatively optimal state with the highest score. The provinces of Shanxi, Gansu, Xinjiang, Jilin, Liaoning, Jiangxi and Anhui have relatively low water use efficiency, but their scale returns are increasing. Therefore, the water use efficiency can be improved by

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appropriately increasing the input of water resources, promote economic development and improvement of people's livelihood. Inner Mongolia, Henan, Yunnan, Fujian, Hebei, Sichuan, Hunan and Guangxi provinces have not achieved optimal water use status. At the same time, the water use scale returns of these provinces is decreasing. This shows that there are water wastes in these provinces, industrial technology and water resources management are relatively backward, and there is room for improvement.

4. Conclusions

According to the above research, as of 2017, the water use efficiency of more than half of China's provinces is in a relatively good state. The means for these provinces to further improve water use efficiency can only be achieved through technological innovation and industrial restructuring. Provinces with low water use efficiency can adjust the distribution and supply of water resources, as well as industrial transformation and upgrading, to improve the efficiency of comprehensive utilization of water resources. The evaluation results provide effective policy recommendations for the efficient use of water resources in China and the improvement of water resources carrying capacity.

5. Acknowledgement

This work was supported by the National Key Research Program of China (No. 2016YFC0401305，2017YFC0506603), the State Key Program of National Natural Science of China (No. 41530635), and the Project of National Natural Foundation of China (No. 51679007, 51379013).

References

1. R. Ramanathan, U. Ramanathan, Y. Bentley, The Debate on Flexibility of Environmental Regulations, Innovation Capabilities and Financial Performance—A Novel Use of DEA, Omega － International Journal Of Management Science.75(2018)131-138．

2. J. Christian-Smith, H. Cooley, P. H. Gleick, Potential water savings associated with agricultural water efficiency improvements: a case study of California, USA, Water Policy.14( 2012) 194-213．

3. A. Charnes, W. W. Cooper, E. Rhodes, Measuring the efficiency of decision-making units, European Journal of Operational Research.3(1979) 339．

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Application of Improved System Degradation Loss Model Based on Risk Theory in Water Resources Carrying Capacity Risk Estimation

Zeji Yi1,2,*, and Xiaohua Yang1,2 1 State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing 100875, China 2 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Zeji Yi, [email protected]

Keywords: water resources carrying capacity; risk theory; degradation loss model; system overload risk; ecosystem service value

1. Introduction

In this paper, water resources carrying capacity and water resource pressure are redefined. Based on the risk theory, this paper discusses the risk source of water resources carrying capacity risk, the hazard-affected body, the hazard of risk source, the exposure degree and vulnerability of hazard-affected body. Two perspectives for calculating risk loss are put forward, that is, the degradation loss and protection cost of natural water resources system, and the degradation loss is calculated based on the reduction amount of the ecosystem service value and the increase of the system overload risk.

The improved calculation method of system degradation loss based on the idea of risk allocation in this paper brings the risk of natural water resources system beyond the critical state into the conventional risk loss calculation. A new model of degradation loss was provided to facilitate the improvement of the implementation of the sustainable development strategy at the Government level.

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Collapsing Mechanisms of the Typical Cohesive Riverbank along the Ningxia-Inner Mongolia Catchment

Guosheng Duan1, Anping Shu*1,2 , Tao Sun,1,2 1 School of Environment, Beijing Normal University, Beijing 100875, China 2 The Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing Normal University, Beijing 100875, China * Correspondence: Tao Sun, Anping [email protected]

Keywords: Ningxia-Inner mongolia; Yellow river; riverbank collapse; BSTEM model; flood & dry season.

1. Introduction

As one of the major sediment sources in rivers, bank collapse ordinarily occurs in Ningxia- Inner Mongolia catchment and to date it caused substantial social, economic and environmental problems in both local areas and downstream locations. To provide a better understanding of this phenomenon, this study consisted in modifying the existing BSTEM model, commonly used to investigate similar phenomena, introducing new assumptions and demonstrate its applicability by comparing numerical results obtained against field data recorded at six gauging stations (Qingtongxia, Shizuishan, Bayan Gol, Sanhuhekou, Zhaojunfen, and Toudaoguai). Furthermore, the impact of multiple factors typical of flood a dry season on the collapse rate was investigated and results should be considered when completing future projects of river adaptation and river restoration.

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Construction of Artificial Seaweed Bed in Marine Ranching

Gang Ding1, 2, Meili Xin1,2, Xiangyu Wang2, Wei Liu1, 2, Fang lv2, and Haiyi Wu1, 2,* 1 Shandong Province Macroalgae Resources Conservation and Application Engineering Research Center，Marine Biology Institute of Shandong Province，Qingdao 266104 2 Engineering Technology Research Center of Qingdao, Qingdao 266104，Marine Biology Institute of Shandong Province，Qingdao 266104 * Correspondence: Haiyi Wu，[email protected]

Keywords: marine ranching; artificial seaweed bed; construction species; shelter

1. Introduction

Seaweed bed is a nearshore marine ecosystem formed by the large brown algae which growing on the hard bottom of the cold temperate continental shelf area and other organisms. The artificial seaweed bed is an appropriate area which in the shallow sea or the inner bay, the seaweed spores were attached to the artificial shelters to form seedlings, or transplantation of the wild seaweed seedlings, so the seaweed community formed by the large-scale propagation.

2. Methodology

Seaweed bed play an active role in primary productivity supply, marine habitat restoration, biological habitat construction and ocean carbon sink. Consequently, the seaweed bed construction has been developing continuously all over the world. Coastal countries represented by Japan and the United States have studied the engineering and technology in the building and rebuilding seaweed bed. In recent years, China has made great efforts to develop marine ranching, among which the construction of artificial seaweed bed has become an important link.

3. Results and Discussion

The key factors of artificial seaweed bed construction were "object" and "human", among which the "object" include the construction species screening, optimization shelters and the sea selection. The "human" mainly include vaccination, fixation, and management.

4. Conclusions

At present, we had carried out the construction of artificial seaweed bed in different sea based on the sexual reproduction techniques of Laminaria japonica, Sargassum thunbergii, Sargassum muticum, and Sargassum horneri, and achieved good demonstration results. Those works have laid the foundation for further serving the marine ranching and ecological civilization construction in China.

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Detailed Modeling of Roof Runoff Reduction Effect of Low Impact Development Practices and Their Combination at Multiple Spatial Scales Pu Zhang1, Lei Chen1, Zhenyao Shen1,* 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Zhenyao Shen, [email protected]

Keywords: urban; storm water management model; roof runoff; low development practice; combination

1. Introduction

Low impact development (LID) practice, as one kind of storm water management approach was proposed to mitigate urban rainwater problems since 1990s [1]. Effectiveness of combined LID have seldom been evaluated [2,3]. Roof runoff is a important part of urban runoff and have many distinctive characteristics. Effectiveness of LIDs and their combination for roof runoff reduction need to be detailed evaluated.

2. Methodology

The widely used Storm Water Management Model (SWMM), developed by USEPA, was applied in this study to the campus of Beijing Normal university (BNU). Experimental green roof was set and its hydrological performance was monitored at multiple amount of rainfall generated by artificial rainfall equipment. Data obtained was used to calibrate and validate green roof module in SWMM to increase confidence of model result. Other modules of SWMM model were calibrated and validated using observation data in 8 rainfall events in 2014 covering rainfall type of light, moderate and heavy.

In this study, the effectiveness of LID and their combination to reduce roof runoff was exclusively evaluated at building scale and campus scale. To explore the reduction effect of LID in building scale, one roof in the campus of BNU was selected and five scenarios, normal roof, green roof, rain barrel, grass field, green roof & rain barrel, green roof & rain barrel & grass field, were developed. To explore the reduction effect of LID in campus scale, five scenarios including directly discharge, current (storm water disconnection), green roof & storm water disconnection, rain barrel & storm water disconnection, rain barrel & green roof & storm water disconnection, were setup for all the roofs in the campus of BNU. Normal roof and directly discharge scenario were taken as base scenarios to calculate reduction indicator of other scenarios.

3. Results and Discussion

The simulation results in building scale show that there is no effluent for all LID scenarios for light and moderate rain events. For heavy and torrential rain events, named 0901, 0830, 114

0729 and 0831 respectively, reduction rate of total volume of rain barrel is 34.5%, 34.1%, 28.7, 13.7%, respectively. For green roof scenario, reduction rate of total volume is 4.6%, 84.6%, 66.0% and 7.7%; reduction rate of peak flow is 81.7%, 95.6%, 96.2, 33.0%; peak delay time is 8, 56, 629, 60 min. For the scenario of green roof & rain barrel, reduction rate of total volume is 38.1%, 100%, 94.0% and 20.7%; reduction rate of peak flow is 89.1%, 100%, 98.1, 32.8%; peak delay time is 28, ∞, 629, 61 min. For scenarios of green field and green field & green roof & rain barrel, effluent only happened at torrential rain. Reduction rate of total volume of these two scenarios is 92.4%, 96.2% respectively; reduction rate of peak flow is 74.0%, 87.0%; peak delay time is 63 and 67 min.

The simulation results in campus scale show that, for light and moderate rain events, i.e. 0804, 0809, 0926, 0823, stormwater disconnection can reduce 22.7%, 22.8%, 23.2%, 10.5% of total volume; 31.3%, 26.8%, 20.1%, 16.5% of peak flow and postpone peak for 4, 3, 3, 3 min. Rain barrel & stormwater disconnection can reduce 42.7%,41.7%,37.6%,24.0% of total volume; 58.6%, 50.2%, 33.8%, 27.8% of peak flow and postpone peak for 7, 5, 4, 5 min. Green roof & stormwater disconnection can reduce 51.9%, 51.8%, 51.0%, 51.7% of total volume; 63.6%, 58.3%, 49.2%, 43.7% of peak flow and postpone peak for 9, 5, 5, 5 min. Green roof & rainbarrel & stormwater disconnection can reduce 51.8%, 51.9%, 51.0%, 51.7% of total volume; 63.6%, 58.5%, 49.1%, 43.8% of peak flow and postpone peak for 9, 5, 5, 5 min.

For heavy and torrential rain events, i.e. 0830, 0901, 0729, 0831, stormwater disconnection can reduce 10.5%, 20.9%, 22.6, 5.9% of total volume; 1.8%, 25.2%, 16.8%, 0.5% of peak flow and postpone peak for 0, 4, 1, 0 min. Rain barrel & stormwater disconnection can reduce 12.7%, 25.6%, 26.7%, 7.4% of total volume; 2.5%, 26.2%, 17.5%, 0.6% of peak flow and postpone peak for 0, 4, 1, 0 min. Green roof & stormwater disconnection can reduce 31.6%, 21.2%, 42.2%, -0.8% of total volume; 36.2%, 42.2%, 42.1%, 1.5% of peak flow and postpone peak for 2, 6, 5, 0 min. Green roof & rainbarrel & stormwater disconnection can reduce 34.6%, 25.8%, 45.5%, 0.4% of total volume; 36.2%, 43.0%, 42.4%, 2.4% of peak flow and postpone peak for 2, 6, 5, 0 min.

The overflow data show that these scenarios can reduce the number of overflow junction for 38.0%, 42.6%, 60.2%, 63.0% respectively; reduce total overflow time for 26.0%, 34.1%, 50.7%, 56.0% and total overflow volume for 36.4%, 44.4%, 51.6%, 61.0%.

4. Conclusions

In building scale, rain barrel and green roof had good performance for light, moderate and heavy rain, but poor performance for torrential rain. Green roof also had poor performance when there was heavy previous rainfall events. Green field had larger reduction capacity. Combination of these LID had best reduction performance. In campus scale, there was no obvious peak delay phenomenon as in building scale. Previous precipitation also affected the reduction effect, especially in the scenarios containing green roof. Rainfall pattern had some influence to LID performance. LID had obvious overflow reduction effects. This

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study provides a important reference for sponge city planing and LID related decision making.

5. Acknowledgement

This work was funded by the State Key Program of National Natural Science Foundation of China (No. 41530635) and the Interdiscipline Research Funds of Beijing Normal University.

References

1. USEPA. Low Impact Development (LID): A Literature Review. United States Environmental Protection Agency, Washington DC. 2000, EPA/841/B00/005.

2. Dietz M.E.; Clausen J.C. A field evaluation of rain garden flow and pollutant treatment. Water Air Soil Pollut. 2005, 167, 123-138.

3. Collins K.A.; Hunt W.F.; Hathaway, J.M. Hydrologic comparison of four types of permeable pavement and Standard Asphalt in Eastern North Carolina. J. Hydrol. Eng. 2008, 13, 1146-1157.

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Effects of Environmental Variables on Carbon and Nitrogen Stable Isotopes of Main Food Sources of Siberian Crane (Grus Leucogeranus) in The Momoge National Nature Reserve, China

Kun Bao1,*, Jingling Liu*, Bo Meng, Bin Sun, Nannan Chen, Lijuan Gao 1 State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, No.19, Xinjiekou Waidajie, Haidian District, 100875 Beijing, China * Correspondence: [email protected]; [email protected]

Keywords: food source; stable isotope techniques; trophic level; environmental variables; national nature reserve

1. Introduction

Changes in environmental variables will lead to degradation of habitat of Siberian Crane (Grus leucogeranus). Study the effects of environmental variables on potential food sources of Siberian Crane is essential for these protection. We analyze the contribution of different food sources to the Siberian Crane by using stable isotope techniques, and study the effects of environmental variables on carbon and nitrogen stable isotopes of main food sources of Siberian Crane. The results showed that the δ13C and δ15N values for primary producers, primary consumers and secondary consumers were -29.18~ -25.36‰, -30.87~ -24.87‰, and -28.74~ -25.11‰, 2.37~7.83‰, 2.56~9.17‰, and 4.87~13.59‰, respectively. Consumers have a trophic level of 1.26±0.28~3.08±0.58 (spring) and 1.26±0.28~3.03±0.58 (autumn), with Siberian Crane having the highest trophic level (TL>3) at the top of the food chain in this region. The main food sources of Siberian Crane during spring and autumn were obtained. Typha angustifolia (mean±SD: 58.4%±9.3%), and Cipangopaludina cahayensis (mean±SD: 27.7%±17.2%) were the main food sources of Siberian Crane in spring; Scirpus mipponicus Makino (mean±SD: 62.0%±12.7%), and Scirpus planiculmis Fr. Schmidt (mean±SD: 21.2%±17.3%) were the main food sources of Siberian Crane in autumn. Using multiple regression and path coefficient analysis to study the effects of environmental variables on the δ13C and δ15N values of main food sources of Siberian Crane. The results showed that

the TP, TOC, COD, DO, pH, TN, BOD5, TSS, NO2-, PO43-, Ca2+, Mg2+, K+, Na+ and water depth were the main environmental variables affecting the δ13C values of the main food

source of Siberian Crane; TN, TOC, COD, pH, DO, BOD5, TSS, Ca2+, Cl-, Mg2+, K+, Na+, PO43- and water depth were the main environmental variables affecting the δ15N values of the main food source of Siberian Crane. We expect that our results can provide valuable information to aid in the conservation of Siberian Crane in this region.

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Estimation of Precipitation Based on Multi-Source Data and Its Application to Hydrological Simulation in a Mountainous Basin

Weichen Wang1, Lian Sun1, and Yanpeng Cai1,* 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Zhexian Zhu, [email protected]

Keywords: Yalong River Basin; Rain gauge observations; Satellite data; Hydrological simulation; Accurate precipitation data.

1. Introduction

The Yalong River Basin (YRB) located in mountainous southwest China has complex terrain and high heterogeneous of climate. However, meteorological stations in the YRB are sparse and distribute unevenly, and datasets based on interpolation of instrumental data or remote sensing of satellite cannot meet the needs of more accurate hydrological simulation.

2. Methodology

Two satellite products (Tropical Rainfall Measuring Mission (TRMM) [1] and the Precipitation Estimation from Remote Sensing Information using an Artificial Neural Network-Climate Data Record (PERSIANN-CDR) and the Stepwise Clustering Analysis method (SCA) were used to divide the YRB into different sub-regions. Two satellite products and three interpolation methods (IDW (Inverse Distance Weighted), CoKriging and ANUSPLIN) were used in different sub-regions to generate the spatial distribution of meteorological elements. The satellite products were used to perform correction based on Bayesian theory and GDA (Geographical Different Analysis) method [2], and their accuracies were checked with distributed hydrological model Variable Infiltration Capacity (VIC).

3. Results and Discussion

Results showed that three sub-regions with obvious latitude and longitude differences were identified, and the results were different in each sub-region. The PERSIANN-CDR caused obvious deviations in precipitation and runoff simulation. The TRMM products were the best in the north sub-region. The Cokriging and ANUSPLIN were the best interpolation methods in the central and south sub-regions respectively. The correction process showed that GDA and Bayesian methods were not ideal in the sparse area of north sub-regions. The GDA method was relatively better for the whole basin and Bayesian method was better in the south sub-regions. In addition, specific influence factor and interpolation method corresponding to specific sub-region resulted in a much better

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correction precision of the whole basin. The simulation of VIC model showed that our dataset significantly promoted the accuracy of hydrological modelling in the YRB compared with other datasets. Our work will be helpful for hydrological simulation in mountainous areas with high heterogeneous of spatial distribution of climate.

4. Conclusions

Hydrological simulation with VIC was sensitive to temporal and spatial variations of precipitation data, especially temporal variations. Compared with PERSIANN-CDR, TRMM products performed better in precipitation time series distribution. TRMM precipitation data is more suitable for the north sub-region of YRB with few gauges. The performance of interpolation and correction methods were more suitable for south sub- region with more gauges, and Bayesian method was better. However, the performance of these methods and data sets fluctuated in the central sub-region.

References

1. Cheema M J M; Bastiaanssen W G M. Local calibration of remotely sensed rainfall from the TRMM satellite for different periods and spatial scales in the Indus Basin[J]. International Journal of Remote Sensing, 2012, 33(8): 2603-2627.

2. Cheema M J M; Bastiaanssen W G M. Local calibration of remotely sensed rainfall from the TRMM satellite for different periods and spatial scales in the Indus Basin[J]. International Journal of Remote Sensing, 2012, 33(8): 2603-2627.

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Evaluation of Ecological Sustainability Based on an Input–Output Structural Decomposition Analysis in Jilin Province, China

Feifei Wu, XiaoHua Yang1,*, ZhenYao Shen 1 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Xiaohua Yang, [email protected];

Keywords: input-output; ecological footprint; carrying capacity; Jilin

1. Introduction

Water is an essential resource for economic, social and environmental sustainability. Water use, especially in developing countries, has exceeded sustainable levels and constrains sustainable development [1]. Input–output analysis (IOA), one of the top-down methods, has been widely used in the evaluation of water footprint flows embodied in sectoral transactions [2-4]. In this study, the IOA method was used to measure the sectoral water footprint in Jilin Province from 1997 to 2012, and then the Structural decomposition method was used to decompose the contributions of the driving factors to water footprint changes.

2. Methodology

Water footprint referred to the water footprint of consumption, the sum of direct and indirect water use (virtual water consumption) [5]. The main economic data used in this study were Jilin IO tables from 1997 to 2012, which contained the latest information available. The input–output table is a necessary calculation tool for depicting the interdependence between sectors within an economic system. First, the total production coefficients matrix A is calculated

푥푖푗 퐴 = {푎푖푗} , 푎푖푗 = (1) 푛×푛 푋푖 where aij is the direct input from sector i needed to increase per monetary unit output in sector j. Second, the Leontief inverse matrix B is calculated

퐵 = (퐸 − 퐴)−1 (2)

3. Results and Discussion

The direct water footprint intensity may reflect water withdrawal per output. From 1997 to 2012, the direct water footprint intensity decreased continuously in all sectors. In 2012, the total water footprint in Jilin Province was 6.3 billion m3. The virtual water footprint was 5.3 billion m3. The indirect water footprint accounted for the majority of water consumption. The indirect water consumption accounted for more than 50% of water use for 39 sectors, and more than 90% for 28 sectors. The total water use coefficient was the

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largest in the primary industry, followed by the tertiary industry (2.31 m3/thousand CNY), secondary industry (1.19 m3/thousand CNY).

4. Conclusions

Using relevant data in Jilin Statistical Yearbook, the water footprint in Jilin Province from 1997 to 2007 was evaluated through input–output analysis and structural decomposition analysis. To promote water conservation in China, water policies should be formulated in coordination with stimulation of the sector’s technology development and the readjustment of sectoral connection.

5. Acknowledgement

This work was supported by the National Key Research and Development Program of China (No. 2017YFC0506603, 2016YFC0401305), the State Key Program of National Natural Science of China (No. 41530635), and the General Program of National Natural Science Foundation of China (No.51679007, 51379013).

References

1. Liu, X.; Guo, P.; Li, F.H.; Zheng, W.S. Optimization of planning structure in irrigated district considering water footprint under uncertainty. J. Clean Pro. 2019, 210, 1270-1280

2. Hoekstra, R.; Van den Bergh, J.C.J.M. Comparing structural decomposition analysis and index. Energy Econ. 2003, 25 (2), 39-64.

3. Hoekstra, A.Y.; Mekonnen, M.M. The water footprint of humanity. Prsoc. Natl. Acad. Sci. U. S. A. 2012,109 (9), 3232-3237.

4. Huang, K.; Wang, Z.; Yu, Y., Yang, S. Assessing the environmental impact of the water footprint in Beijing, China. Water Policy 2015, 17, 777-790.

5. Vanham, D.; Bidoglio, G. A review on the indicator water footprint for the EU28. Ecol. Indic. 2013, 26, 61-75.

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Experimental Study on Hydrodynamics of Artificial Reef with Different Spatial Layout in Offshore Area

Anping Shu, Jiping Qin1,*, Shu Wang, and Mengyao Wang 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Jiping Qin, [email protected]

Keywords: artificial reef; flow field effect; spatial layout; PIV experiment

1. Introduction

Artificial reefs are structures setting up in the sea to improve the ecological environment and provide places for fish to breed, grow, catch and harbor enemies. At present, artificial reefs construction has been widely carried out with good results. Different arrangement of artificial reef will produce different hydrodynamic characteristics and flow field effects， of which mainly improve the marine ecological environment. The characteristics of the flow field in reef area are closely related to the type, structure, size and layout of the reef. Therefore, it is of great significance to study the flow field effect and scale of artificial reefs with different spatial layouts. To optimize Juehua Island offshore waters on the arrangement of artificial reefs, plans to launch the 3 kinds of artificial reef (M type proliferation reef, square ecology reef and tetragonal size set fish reef), design several typical kinds of arrangement, and make reef models according to the geometric scale of 50:1. Using Particle Image Velocimetry system, the flow field of three types of reefs under typical arrangement and combination modes will be studied experimentally in a flume. It is anticipated that the characteristics of hydrodynamic parameters such as velocity, upwelling, back eddy current and turbulence intensity in the flow field generated by artificial reefs with different arrangements, the distribution and effect of flow field around artificial reefs with different arrangements, and the influence range of reefs on flow field will be obtained. Then the optimized spatial layout of artificial reefs in the offshore waters of Juehua Island will be obtained, which provides a technological basis for the release form of artificial reefs.

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Experimental Study on the Scour at Downstream of Trapezoidal Weir Structures

Milad Abdollahpour1,*, Nasrin Hassanpour 1, Ali HosseinzadehDalir1, Carlo Gualtieri2

1 Department of Water Engineering, University of Tabriz, Tabriz 5166616471, Iran 2 Department of Civil, Architectural and Environmental Engineering, University of Napoli Federico II, Napoli 80125, Italy. * Correspondence: Milad Abdollahpour, [email protected]

Keywords: Hydraulic structures, Scour, River restoration, Trapezoidal weir

1. Introduction

Grade control structures like trapezoidal weirs are recommended for stabilizing river bends and bed, for the development of fish habitat and the control of erosion by reducing stream slope and flow velocity [1, 2]. The aim of this study is to experimentally analyze the effect of arms slope of a trapezoidal weir on downstream scouring in a sinusoidal flume under different flow conditions.

2. Methodology

The experiments were conducted in the hydraulic laboratory of the University of Tabriz in a horizontal rectangular flume with a sinuosity of 1.12. All tests were carried out in clear

water condition. Sand with a median diameter of d50 =1.2 mm and specific gravity (Gs) of 2.60 was used in the experiments. Figure 1 illustrates the weir characteristics and sizes.

Figure 1. Sketch of the Trapezoidal weir parameter (a) Plan view (b) Cross sectional view of weir

3. Results and Discussion

For each slope of the arms, five inflow Froude numbers (Fr( were tested. In all models the maximum scour depth, length, and width were measured. The results showed that the maximum scour size decreased as the arms slope and Fr decreased. The experimental data indicated that an important parameter was the slope of weir arms. The flow downstream of the weir was re-directed away from the banks to the center of the flume. This pattern was consistent with those from Pagliara and Kurdistani [3] and Bhuiyan et al. [4]. Furthermore, the largest scour was located at the flume centerline, where large local 123

velocities were expected. The results were compared with those from Abdollahpour et al. [5] for W-weir. While W-weir created two scour holes, trapezoidal weir created only one scour hole.

4. Conclusions

The following main conclusions could be drawn from this study about trapezoidal weir:

⚫ The flow downstream of the weir were re-directedtowards the center of the flume, where scour was located. Hence, this weir can be installed in a river bend for bank protection.

⚫ An important parameter for trapezoidal weir is the pitch (slope) of the arms. The scour size increased as arms slope (Z) increased. The maximum scour size increased as the inflow Froude number decreased.

References

1. Rosgen, D.L. The Cross-vane, W-weir and J-hook vane structure: Their description and application for stream stabilization and river restoration. In Proceedings of the Wetlands Enineering and River Restoration Conference, Reno, VA, USA, 27–31 August 2001; ASCE: Reston, VA, USA; pp. 1–22.

2. Abdollahpour, M.; Dalir, A. H.; Farsadizadeh, D.; & Shiri, J. (2017). “Assessing heuristic models through k-fold testing approach for estimating scour characteristics in environmental friendly structures”. ISH J. Hydraul. Eng., 1-9.

3. Pagliara, S.; and Kurdistani, S. M. (2013). “Scour downstream of cross-vane structures”. J. Hydro-Environ. Res., 7 (4), 236–242.

4. Bhuiyan, F.; Hey, R. D.; and Wormleaton, P. R. (2007). “River restoration using W-weir”. J. Hydraul. Eng., 133(6), 596–609.

5. Abdollahpour, M.; Hosseinzadeh Dalir, A.; Farsadizadeh, D.; and Gualtieri, C. (2017). “Experimental Study on Erosion and Sedimentation Patterns Downstream of a W-weir in a Sinusoidal Mild Bend”. Water, 9(9), 638.

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Extreme Value Analysis of Significant Wave Height in the South Yellow Sea Xi Feng1,2,*, Huichao Li1,*, Jiajing Zhao1, Li Ji1, and Weibing Feng1 1 College of Harbor, Coastal and Offshore Engineering, Hohai University 210098, Nanjing, Jiangsu Province 2 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, No.1 Xikang Road 210098, Nanjing, Jiangsu Province * Correspondence: Xi Feng, [email protected], Huichao Li, [email protected]

Keywords: The South Yellow Sea; wave statistics; extreme value; generalized extreme distribution; peak over threshold; return period

1. Introduction

The third-generation nearshore wave model SWAN generates 40-year long wave climatology in the region of the South Yellow Sea of China. A sophisticated wave model is developed through calibration with a couple of popular reanalysis wind field datasets and more accurate near-shore topography. The combination of ECMWF wind datasets with the consideration of wave energy dissipation mechanisms including white capping, wave breaking and bottom friction shows a better performance in wave heights, while it highly offsets the limitation in accuracy and coverage of the wave measurements in this area.

Several areas with different features are divided according to depth, topography and geographical location to clarify the spatial distribution characteristics of the significant wave height in the South Yellow Sea, especially in the region of sandbank area. The regional wave heights are compared and found that the wave heights in the southern waters were larger than those in the northern waters, which may be the reason why the southern area is more vulnerable to tropical storm. In addition, the wave height gradually decreases from the deep sea to the shallow water area, especially in the region of sandbank area, the wave height is smaller than that in the north and south sides. It can be attributed to extensive wave energy dissipation on the radial sand ridges and the weakening of wind- stress by the land topography.

The distribution of the 100-year return wave height of the whole region is given by the generalized extreme value distribution function suitable for the annual extremum and the monthly extremum, as well as the generalized Pareto distribution suitable for the Peak- over-threshold method. In order to get more accurate results, the distribution map with the three methods is listed, after which the comparative analysis has been performed.

Using the mean return wave height from the three methods, the influence of different data length varying from 10-year to 40-year is studied. The result shows that the longer data causes the lower return wave height. Through the analysis of the twenty-year significant wave height of multiple groups which have different starting date (such as 1979-1999, 1984-

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2004, 1989-2009 et al.), it is founded that the predicted wave height shows a periodical change with the increase of the starting date of the data set. We have analyzed wind field data and found that the frequency of the gales occurred vary from different years, which was closely related to the El Niño phenomenon at that time.

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Fate and Partitioning of Legacy and Alternative pass in Pore Water and Sediment of the Daling River, China

Lijuan Gao1,*, Jingling Liu1 1 State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, No.19, Xinjiekou Waidajie, Haidian District, 100875 Beijing, China * Correspondence: [email protected]; [email protected]

Keywords: PFASs; fate; partitioning; pore water; sediment

1. Introduction

As a class of surfactants with good performance, per- and polyfluoroalkyl substances (PFASs) have been widely used in numerous industrial and household products. Through the production and use of these products, PFASs can be released into the environment, and they have been found ubiquitous in water, sediment, wildlife, and humans [1]. Because of their persistence, bioaccumulative potential, and possible adverse effects on living organisms, PFASs can cause high risk to the aquatic ecosystem and humans. Numerous studies have shown that the aquatic environment is an important sink and reservoir of PFASs [2], but data on the occurrence of PFASs in pore water as well as the partitioning of PFASs between sediment and pore water are scarce, thus compromising proper pollution control strategies for water resources management. The results of this study provide a fundamental basis for the understanding of media distribution and transport of PFASs between pore water and sediment.

2. Methodology

In the study reported here, 19 sediment samples were collected from the Daling River adjacent to the Fuxin fluorochemical manufacturing facilities in China for a determination of the PFASs in pore water and sediment. We investigated the concentration profiles of the legacy and alternative PFASs by using SPE cartridge clean-up followed by high- performance liquid chromatography coupled to tandem mass spectrometry (HPLC- MS/MS). Furthermore, the distribution behavior of PFASs between sediment and pore water was examined.

3. Results and Discussion

The total concentrations of PFASs (∑PFASs) ranged from 170 to 9949 ng L-1 in pore water column and from 1.50 to 39.4 ng g-1 on a dry weight basis (dw) in the sediment fraction. Perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS) were the predominant PFASs in the pore water. PFBA and PFBS were the predominant congener in

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sediment from the Xi River tributary, whereas PFBA, PFBS, and perfluorooctane sulfonate (PFOS) were found to be the most abundant PFASs in sediment from the upstream of Xi River and Daling River zone. Hexafluoropropylene oxide dimer acid (HFPO-DA) and 6:2 chlorinated polyfluorinated ether sulfonic acid (6:2 Cl-PFESA, trade name F-53B) were detected in most of the sampling sites，but their concentrations were relatively lower with the highest concentration of 44.5 ng L-1 and 0.990 ng g-1 dw for HFPO-DA, and 1.52 ng L-1 and 0.549 ng g-1 dw for 6:2 Cl-PFESA, respectively. The average Kd values for PFASs ranged from 2.44 L/kg (PFBA) to 2640 L/kg (PFOS). The sediment-specific parameters including dissolved organic carbon in pore water and the organic matter in solid phase sediment as well as the physicochemical characteristics of PFASs, such as the perfluorocarbon chain length and functional group can influence partitioning behavior of PFASs in the real environment.

4. Conclusions

Our results showed the insitu fate and partitioning of legacy and alternative PFASs between pore water and sediment. The pore water is an important sink for short-chain PFASs, while the sediment is the reservoir for HFPO-DA and 6:2 Cl-PFESA. The partitioning behavior of PFASs depends on their physicochemical characteristics as well as on sediment-specific parameters. These data are essential for modelling the transport and environmental fate of PFASs.

5. Acknowledgement

This study was supported by Research and Development of Ecological Water supplement and EcoHydrological Regulation Technology of Degraded Wetland (2016YFC0500402) and The Interdiscipline Research Funds of Beijing Normal University.

References

1. Zhou Z.; Liang Y.; Shi Y.; et al. Occurrence and Transport of Perfluoroalkyl Acids (PFAAs), Including Short-Chain PFAAs in Tangxun Lake, China[J]. Environmental Science & Technology, 2013, 47(16):9249-9257.

2. Ahrens L.; Yamashita N.; Yeung L.W.Y., et al. Partitioning Behavior of Per- and Polyfluoroalkyl Compounds between Pore Water and Sediment in Two Sediment Cores from Tokyo Bay, Japan[J]. Environmental Science & Technology, 2009, 43(18):6969-6975.

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Fuzzy Comprehensive Evaluation of Water Resources Carrying Capacity in Chongqing Municipality

Xunjian Long, Ling Fan, Xuerou Weng, Yan Ye1,* 1 College of Resources and Environment, Southwest University, Chongqing 400715, China * Correspondence: Yan Ye, [email protected]

Keywords: water resources carrying capacity; analytic hierarchy process method; fuzzy comprehensive evaluation method; coupling

1. Introduction

Water resources carrying capacity (WRCC) can reflects human-nature interaction in many ways, such as productive system within water resources, eco-environmental and social economical system [1]. Moreover, it is also an important index on water resources security. A typical representation would be happen between water resources over loading and regional economic development. Many researchers regard this issue as one of the most important and puzzled questions, over the past 30 years [2].

Chongqing city is the youngest city that administer directly under the central government, located in southwest China. In the past few years, rapidly Chongqing's economic development demands more water resources [3]. And under this background, it is urgency to estimate the water resources status and sustainable pressure in study region. Therefore, this study provides a beneficial trying of WRCC by coupling model of analytic hierarchy process (AHP) and fuzzy comprehensive evaluation method.

2. Methodology

For WRCC assessment, there are many kinds of calculation methods. And the common popular methods include conventional trend method, comprehensive evaluation, and system dynamics etc. And the comprehensive evaluation includes grey evaluation model method, extension mater-element evaluation and fuzzy comprehensive evaluation method. For these methods, a simple, accurate and efficient method can provide benefits for research work. Based on this principle, this study selected the combination method that base on fuzzy comprehensive evaluation method and AHP method, to estimate the WRCC.

3. Results and Discussion

3.1 The evaluation index system of WRCC

Regarding all the affected factors, WRCC can be considered as a system that combined by sustainable carrying capacity, sustainable pressure and regulation ability. In General, the three objects usually referred to four aspects, which is composed by the status of water resources, social development, economic conditions and eco-environment, respectively [4].

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In order to find out the WRCC of Chongqing, this manuscript collected 13 factors for index system construction, from 2003 to 2017. And the evaluation system was build up.

Based on the AHP calculation rule, the weights of selected indicators were obtained and the membership matrix R of each year was build up.

3.2 evaluation results in Chongqing.

The results show that, during 2003 to 2017, the evaluation grade of WRCC is V2, in Chongqing. It appears that WRCC is in medium status and only slightly constraining force reflect on human society. For the coupling results, it is clearly to find out that the lowest total evaluation score presented in year 2003 and highest score presented in year 2014. The results also show that final evaluation score is among 0.4638 and 0.5928, from 2003 to 2017.

4. Conclusions

Based on coupling model of AHP and fuzzy comprehensive evaluation method, 13 statistical indices, from 2003 to 2017, were collected for the WRCC calculation. The results show that regardless of different weights of membership grade, V2 is the first choice on WRCC in Chongqing city. In other words, the status of WRCC is in moderate balance condition. And the water quality was partly affected, but still sustainable.

According to the complexity calculation score, the final value of A is absolutely higher than 0.5, since 2006. The most direct reason is that water resources development potential is gradually recovering, following various policies and measures carried out. What’s more, this study implies consistent results with Chongqing water resource bulletin, such as continuous decreasing on total water consumption rate, water quality improvement persistently, keeping increasing on water resource recycling rate, better utilization on water resources allocation. For all the indicative conditions, it seems that this coupling model on WRCC is feasible.

References

1. Gong G. ． China's water shortage could shake world food security. Future ＆ Development, 1998, 11, 16－21．

2. He C.S.; Frank W.. Water sustainability and watershed ecosystem health. Ecosystem Health and Sustainability. 2018, 4, 241-242．

3. Gong J.P.; Zhang W.; Hong J.J.; et al.. Chongqing Water Resources Capacity Analysis and Utilization Discussion of Sustainable Development. Southwest China Journal of Agricultural Sciences.2011,24, 2429-2433.

4. Jin J.L.; Dong T.; Li J.Q.; et al.. Water resources carrying capacity evaluation method under different carrying standards. ADVANCES IN WATEＲ SCIENCE. 2018,29, 31- 39.

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High-Resolution Monitoring of Bed-Level Dynamics in Intertidal Environments Using Laser Ranging Technology

Juanling Zhou1, Zhan Hu1,* 1 The school of marine science, Sun Yat-sen University, Zhuhai, 519082, China * Correspondence: Zhan Hu, [email protected]

Keywords: intertidal; surface bed-level dynamics; laser-SED; high resolution monitoring;

1. Introduction

Short-term mophodynamic processes in tidal flats are significant to explain the mechanic of change under sea-level rises or climate change[1]. Accurate in situ measurements are needed to reflect the complex of processes (physical/biophysical) in tidal flats. To elevated the method of bed level observation, we introduce a newly developed laser-SED to obtain a set of high resolution bed level data under different vegetated conditions.

2. Methodology

Laser-SED the newly invented instrument laser-SED made use of laser ranging. It could avoid instrument self-disturb by not touching the ground surface. It can obtain data with millimeter vertical resolution. At the same time, we could download the real time bed level data through its GPRS communication.

Comparison with the SEB measurement to test the performance of the laser-SED, we compared its measurements with the traditional manual measurement of bed level change (SEB) with a vertical resolution of 0.5mm[2].

860 Laser-SED ③ ④ 100 ⑦ ⑨

⑤

105 ② ⑧ ① ⑩ ⑥ ⑧

0 1 SEB bed surface time

∆ bed surface Wave logger ADP

Figure 1 a) designation of the laser-SED; b) instruments deployment in the field

Field campaign in Hailing island, Yangjiang to show how the laser-SED can be used to obtain time series of short-term bed-level dynamics, we chose a profile of 3 spots with different vegetated conditions, and deployed a set of hydrodynamics observation combined with laser-SED and SEB measurements. 131

3. Results and Discussion

Performance of the laser-SED the regression function is y = 0.99 ∗ x + 4.36 with 푅2 = 0.69 and correlation coefficient R = 0.83 , indicating a good agreement between this two methods.

Different surface-elevation dynamics measured by laser-SED the bed-level data had shown that the study profile tended to accretion. Although the largest accretion magnitude happened at the spot of bare flats, its daily bed-level change is largest, too. And the other two spots with sparse to dense Figure 2 comparison of laser-SED and SEB vegetated accreted and changed very slightly.

4. Conclusions

Result of this study has showed that the newly developed laser-SED can accurately monitor the surface bed level dynamics. And the observation results indicating that large hydrodynamic forces and lack of vegetation lead to large fluctuation of the surface bed. The mainly advantages of this laser-SED are 1): continuous monitoring; 2): untouchable to the measure ground; 3): real time return of the bed level data.

5. Acknowledgement

This study has been supported by Joint Research Projects (NSFC – NWO – EPSRC: Sustainable Deltas. Application no. ALWSD2016.00X).

References

1. M. van der Wegen, B. Jaffe, A. Foxgrover, D. Roelvink, Mudflat Morphodynamics and the Impact of Sea Level Rise in South San Francisco Bay, Estuaries Coasts. 40 (2017) 37– 49. doi:10.1007/s12237-016-0129-6.

2. Z. Hu, W. Lenting, D. van der Wal, T.J. Bouma, Continuous monitoring bed-level dynamics on an intertidal flat: Introducing novel, stand-alone high-resolution SED- sensors, Geomorphology. 245 (2015) 223–230. doi:10.1016/j.geomorph.2015.05.027.

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Interplay between Grid Resolution and Pressure Decimation in Non-hydrostatic Modeling of Internal Waves

Jian Shi 1,* 1 Hohai University, Nanjing 210098, P.R.China * Correspondence: Jian Shi, [email protected]

Keywords: Non-hydrostatic wave model, Pressure Decimation and Interpolation, Wave Dispersion, Numerical dissipation, Numerical diffusion

1. Introduction

The Pressure Decimation and Interpolation (PDI) method is an effective numerical technique to improve the computational efficiency of a non-hydrostatic model. We carried out an analysis of the wave dispersion relation and quantitative measurements of numerical dissipation and diffusion affected by the PDI scheme in modeling of internal waves. The linear analysis on the wave dispersion relation shows that the accuracy in predicting wave dispersion depends highly on how well the vertical structure of the non- hydrostatic pressure is represented over depth. The accuracy is not only dependent on the resolution of the pressure grid, but also on the interpolation method. The third-order spline interpolation provides a more accurate wave dispersion relation than the lower-order (linear and quadratic) interpolation. Quantitative measurements of wave energy transfer from the basin-scale internal seiche to small-scale internal solitary waves, as well as numerical dissipation and diffusion in the PDI model, were performed in the simulation of internal waves. Results show that the resolution of the pressure grid has a major effect on the wave dispersion but a negligible effect on the numerical dissipation and diffusion. The velocity grid resolution has a significant influence on the numerical diffusion and a minor effect on the numerical dissipation.

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Lattice Boltzmann Method for the Lateral Flow Numerical Simulation

Yu Ding1,* 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Yu Ding, [email protected]

Keywords: lattice Boltzmann method, lateral flow, numerical simulation, overland flow

1. Introduction

Overland flow drained into rivers is the process of the transverse hydrological connectivity, which can be modeled by the lateral flow numerical model. This study utilized the lattice Boltzmann method to establish the numerical model of horizontal structural hydrological connectivity, i.e. the lateral flow model. The v-shaped catchment area was selected as the application area, simulating rain-induced overland flow on slope and then flows into the river and testing the accuracy of the lattice Boltzmann method for lateral flow dynamic simulation. In addition, the lattice Boltzmann method combined with Lagrange particle tracking method was used to set up the cross functional hydrological connectivity numerical model. This model was used to simulate and predict the micro plastic particles motion in slope runoff and the channel.

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Modelling Response of the Wadden Sea Tidal Basins to Relative Sea-level Rise

Zheng Bing Wang1,2,3 1 Deltares, Delft, The Netherlands 2 Delft University of Technology, Delft, The Netherlands 3 State Key Laboratory of Water Environment Simulation and School of Environment, Beijing Normal University, Beijing, China * Correspondence: [email protected]

Keywords: Long-term morphodynamic development; sea-level rise; Wadden Sea; Tidal flat

1. Introduction

The Wadden Sea contains the world largest coherent tidal flats and spans a distance of nearly 500 km along the northern coasts of the Netherlands and the North Sea coast of Germany and Denmark. It is separated from the North Sea by a series of barrier islands, and characterized by a wide variety of channels, sand and mud flats, gullies and salt marshes. Climate change and especially the associated acceleration of sea-level rise forms a serious threat to this ecologically valuable system. Subsidence of seabed due to e.g. gas and salt extraction contributes to additional relative sea-level rise. The intertidal flat in the Wadden Sea can be drowned when the sea-level rise rate exceeds a critical limit [1]. This means that the intertidal flats are then permanently inundated seriously affecting the ecological functioning of the system. However, the determination of this critical limit and the modelling of the transient process of how a tidal basin respond to accelerated sea-level rise is still a subject of research, see e.g. [2], [3] and [4]. In this contribution we revisit the modelling of the response of the Wadden Sea tidal basins to sea-level rise. The main questions we want to address are: what are the possibilities and restrictions of the various models? How can the different types of models be applied in combination with (restricted) field data for reliable future predictions?

2. Methodology

Two types of morphodynamic models are considered, the process-based models e.g. Delft3D and the aggregated models e.g. ASMITA (see e.g. Van Goor et al., 2003). The relations between the two types of models are made clear by analysing the model formulations. The analysis reveals the essential differences between the two types of models and makes clear their possibilities and restrictions. A problem for modelling impact of relative sea-level rise is the model verification / validation. Direct validation of the model concerning e.g. drowning of tidal flats due to sea-level rise is practically impossible as it would require field observations of at least centuries. Analysis based on the ASMITA model provides insight on how the long-term morphodynamic modelling for response to

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sea-level rise can be validated using shorter-term field observations and process-modelling using complex models.

3. Results and Discussion

Comparison between Delft3D and ASMITA reveals that the only essential differences between the two types of models is the level of (spatial and temporal) aggregation and the type of empirical knowledge implemented in the model. In ASMITA the empirical relations defining morphological equilibrium are used instead of the empirical sediment transport formulas in Delft3D. The high level of aggregation makes ASMITA capable to relate e.g. the critical rate of sea-level rise explicitly to the model parameters, but on the other hand the parameter setting of ASMITA needs careful consideration as the model parameters are less directly measurable than those in Delft3D. Theoretical analysis on the ASMITA model reveals that the critical sea-level rise rate is determined by the morphological equilibrium state and a time scale. Surprisingly, this time scale is not the same as the morphological time scale for a disturbance to the morphological equilibrium to decay in time. The power in the relation between sediment transport capacity and flow velocity does not influence the time scale determining the critical sea-level rise rate but it does influence the decaying time scale of a disturbance to morphological equilibrium. This insight can be used for better guiding the analysis of the (limited available) field data concerning morphological development for determining the parameters in morphodynamic models for simulating the response to sea-level rise. This makes the modelling of the response of the Wadden Sea to future sea-level rise, based on the combined use of different type of models and available field data, more reliable.

References

1. Van Goor, M.A., Zitman, T.J., Wang, Z.B. & Stive, M.J.F., 2003. Impact of sea-level rise on the morphological equilibrium state of tidal inlets. Marine Geology 202: 211–227.

2. Fokker, P.A., Van Leijen, F., Orlic, B., Van der Marel, H. & Hanssen, R., 2018. Subsidence in the Dutch Wadden Sea. Netherlands Journal of Geoscience, Netherlands Journal of Geosciences, 97-3: 129-181.

3. Vermeersen, L.L.A., Slangen, A.B.A. et al., 2018. Sea level change in the Dutch Wadden Sea. Netherlands Journal of Geoscience, Netherlands Journal of Geosciences, 97-3: 79- 127.

4. Wang, Z.B., Elias, E.P.L., Van der Spek, A.J.F. & Lodder, Q.L., 2018. Sediment budget and morphological development of the Dutch Wadden Sea - impact of accelerated sea- level rise and subsidence until 2100. Netherlands Journal of Geosciences, 97-3: 183-214.

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Numerical Study of Sulfonamide Occurrence and Transport at the Near-Shore Area of Laizhou Bay

Liming Xing2, Haifei Liu2,*, Wenxian Guo1, Yu Ding2, Zhiming Ru2, Gangqin Tu2, and Xuerong Wu2 1 School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou, 450045, China 2 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Haifei Liu, [email protected]

Keywords: Lattice Boltzmann method; aquatic environment; antibiotic; Sulfonamide; Laizhou Bay

1. Introduction

Antibiotics are extensively applied in aquaculture for the treatment of microbial infections and to improve production [1]. Among various antibiotics, sulfonamide (SA) are popular in fish farming, and SA residues in the aquatic environment have detrimental effects on both ecosystem and human health [1]. Understanding the fate of SA in the aquatic environment is a basic necessity to provide an approach to solving the current problem. In this study, a two-dimensional lattice Boltzmann model was introduced to investigate the transport and occurrence of SA in the Laizhou Bay, a prosperous aquaculture area in China. The model is based on the shallow water equations and advection-diffusion equation with the Bhatnagaar-Gross-Krook scheme. This model provides a potential universal method for the simulation of the fate of antibiotics in the aquatic environment.

2. Results and Discussion

Figure 1: The occurrence of SA on the 30th days in Laizhou Bay

Due to the high density of human activities and the main rivers flowing into the bay, the high SA concentrations show the dominant impact of riverine inputs on the marine environment. This coincides with the previous work about the source of antibiotics in the marine system [2]. Most estuaries are located in the northwest of the bay, leading to higher

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pollution in this area. Meanwhile, the bay is semi-enclosed with poor water exchange, resulting in high-level environmental risk. Moreover, the results for the selected points are lower than those in most river estuaries, which may result from the seawater dilution when rivers discharge into the bay [3].

3. Conclusions

This paper proposes a two-dimensional model, coupling hydrodynamic and water quality models. The lattice Boltzmaann method is used to discretize the model and the coefficients for the diffusion and relaxation times are calibrated. Furthermore, the coupled model is applied to simulate the transport and occurrence of SMX and SMZ in Laizhou Bay. The numerical results are in good agreement with the experimental data, showing that the proposed model is able to predict the transport of sulfonamide.

4. Acknowledgement

The financial supports of the National Key R&D Program (2018YFC1406401) and the National Natural Science Foundation of China (51779011) are gratefully acknowledged.

References

1. Fisheries, F., Department, A. The state of world fisheries and aquaculture. Rome Italy Fao. 2009, 4, 40–41.

2. Kümmerer, K. Antibiotics in the aquatic environment-a review-Part II. Chemosphere. 2009, 75, 435–441.

3. Zhang, R., Zhang, G., Zheng, Q., Tang, J., Chen, Y., Xu, W., Zou, Y., Chen, X. Occurrence and risks of antibiotics in the Laizhou Bay, China: Impacts of river discharge. Ecotoxicology & Environmental Safety. 2012, 80, 208–215.

4. Zou, S., Xu, W., Zhang, R., Tang, J., Chen, Y., Zhang, G. Occurrence and distribution of antibiotics in coastal water of the Bohai Bay, China: Impacts of river discharge and aquaculture activities. Environmental Pollution. 2011, 159, 2913–2920.

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Reasonable Ratio Threshold of Water Area in Plain River Network Region Based on PCSWMM model A Case Study of Changzhou

Chunhui Li1,*, Cong peng, Jiuhe Bu, Xuan Wang, and Zhifeng Yang 1 Ministry of Education Key Laboratory of water-sediment Science, School of Environment, Beijing Normal University, Beijing, 100875, China * Correspondence: Chunhui Li: [email protected]

Keywords: Reasonable Ratio Threshold of Water Area; Plain River Network; PCSWMM; Changzhou

1. Introduction

The Yangtze River Delta Urban Agglomeration is an important engine and leading development area of the Yangtze River Economic Zone, which plays an important strategic role in the development of modern economic society. However, despite it is one of the best areas for urbanization, the conflict between man and environment has become more and more serious. The unreasonable urban construction and development has destroyed the structure of urban water system, occupied the water bodies, such as rivers and lakes, shrinked the area and degraded the function of urban water surface, coupled with extreme climate and frequent human activities, resulting in serious deterioration of urban qautic ecological environment and flood disasters. Therefore, it is necessary to determine the reasonable area of urban water surface so that it can effectively play the overall service function, and then guarantee the sustainable development of natural ecology and economic society.

2. Methodology

In this study, Changzhou, one of the central cities in the Yangtze River Delta, was selected as a case study. Through the interpretation of urban water surface in the historical period, a rational water area ratio evaluation system based on PCSWMM model was established with the of orientation core service function identification, and the reasonable water surface ratio meeting the criteria of flood discharge and waterlogging removal was quantatively evaluated. The reasonable ratio threshold of water surface to meet the objective of minimizing the cost of system engineering was analyzed under different planning scenarios combined with the concept of sponge city.

3. Results and Discussion

The main results are as follows:(1) The Modified Normalized Water Index (MNDWI) was used to interpret the urban water surface of Changzhou City from 1986 to 2016, and the dynamic trend of shrinkage (1986-1998)-recovery (1998-2010)-decline (2010-2016) was

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obtained. The correlation analysis based on statistic data such as rainfall and socio- economic data revealed that anthropogenic activities were the main significant factor causing the variation of natural water surface area.(2) The research system of reasonable water area ratio in Changzhou City based on the function of flood control and waterlogging removal and PCSWMM model was established. Through the design of simulated rainstorm and the establishment of standards for flood control and waterlogging removal, the optimal solution of reasonable water area ratio was obtained by coupling the urban hydro-dynamic model and economic programming model. The results showed that the reasonable ratio thresholds of water area of traditional planning and LID planning are 5.78%-6.02% and 5.63%-5.88% respectively, while meeting the requirements of flood control and waterlogging discharge and minimizing the cost of system engineering.

4. Conclusions

The results showed that the reasonable ratio thresholds of water area of traditional planning and LID planning are 5.78%-6.02% and 5.63%-5.88% respectively, while meeting the requirements of flood control and waterlogging discharge and minimizing the cost of system engineering. The research can provide a basis for the management and regulation of urban water space in the future.

5. Acknowledgement

This work is financially supported by National Key Research and Development Program (2017YFC0404505)

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Relationship between Inorganic P Fractions and the Microbial Biomass P in Sediments under Different Types of Wetlands in Hulunbuir Grassland

Zhaoyan Diao1，Jing He1,*, Zhirong Zheng1, Derong Su2, and Shihai Lv1 1 Chinese Research Academy of Environmental Sciences, Beijing, 100012, China 2 Beijing Forestry University, Beijing, 100083, China * Correspondence: Jing He, [email protected]

Keywords: microbial biomass P; inorganic P; Olsen-P; wetlands; Hulunbuir Grassland

1. Introduction

Soil microbial biomass phosphorus (P) is the phosphorus of all living microorganisms contained in the soil, the main ingredient is nucleic acid, phospholipids, other mineralized organic phosphorus and a part of inorganic P. Its usually accounted 1.4% to 4.7% for microbial dry matter [1], due to the rapid turnover of soil microbial biomass P, it is an important source of plant available P, and is very important for regulating the plant availability of phosphorus and the biogeochemical cycle of phosphorus [2]. Soil microbial biomass P is sensitive to environmental changes. Accurate determination of soil microbial biomass P can help to better understand the changes in soil microbial biomass P due to changes in environment and human activities, and is of great significance for soil fertility and soil nutrient availability [3].

The first aim of the present study was to investigate the content of inorganic phosphorus content and microbial biomass phosphorus content in different types of wetland in a group of 24 wetland sediments. The second aim was to investigate the relationship between microbial P and P fractions, especially the inorganic P fractions.

2. Methodology

Sediment samples from 24 areas surrounding Hulunbuir Grassland, northeast China, were collected on mid of July 2017 at 0 to 10 cm depth. According to the Wetland Classification System of Wetland Convention, the sediments belonged to four types of wetland: permanent river wetland (W-river), permanent freshwater lake wetland (W-lake), grassy marsh wetland (W-marsh) and reservoir wetland (W-reservoir). Inorganic P was fractionated according to a conventional fractionation method [4]. Soil microbial biomass P with Olsen was also measured by the fumigation-extraction method [5]. Correlation and regression analysis was performed using OriginPro 9.1.0.

3. Results and Discussion

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The fractions Al-P, Fe-P, Ca-P and Oc-P contributed overall medians of 8.39%, 6.94%, 39.40% and 8.06%, ranging from 0.47% to 61.78%. Microbial biomass P contributed an overall median of 2.07% to total P and of 48.92% to Olsen-P. Multiple regression analysis revealed the important relationships of microbial biomass P with Olsen-P, Al-P and Ca-P. The contribution of microbial biomass C/P totally increased with increasing total P, especially in sediments low in Fe-P. The contribution of microbial biomass P to total P generally decreased with Fe-P, particularly in sediments low in Ca-P. The ratio of microbial biomass P to Olsen-P generally increased with increasing the contents of Al-P, predominantly in sediments low in Ca-P. The content of Fe-P and Ca-P had a capital contribution to bioavailable phosphorus, and which will cause a great risk of potential phosphorus release in sediment [6]. The content of Fe-P and Ca-P could be comprehensively characterized by the ratio of microbial biomass P and Total P. Hence, the Microbial biomass P/Total P could be used to forecast the phosphorus conditions of the wetland sediments.

4. Conclusions

The contents of P were highest in the grassy marsh wetland sediments. Multiple regression analysis revealed the true relationships of microbial biomass P with Olsen-P, Al-P and Ca- P. The contribution of microbial biomass C/P totally increased with increasing total P, especially in sediments low in Fe-P. The change range of microbial biomass C/P ratio is 4.14 to 50.09. Microbial biomass P/Total P should be considered to forecast the phosphorus storage status of the wetland sediments.

5. Acknowledgement

This work was financially supported by National Key Research & Developmental Program of China (2018YFF0213405, 2018YFC0507304 and 2017YFC0504004).

References

1. Joergensen RG; Kübler H; Meyer B; Wolters V. Microbial biomass phosphorus in soils of beech (Fagus sylvatica L.) forests. BIOL FERT SOILS. 1995, 19, 215-219.

2. Sugito T; Yoshida K; Takebe M; Shinano T; Toyota K. Soil microbial biomass phosphorus as an indicator of phosphorus availability in a Gleyic Andosol. SOIL SCI PLANT NUTR. 2010, 56, 390-398.

3. Smith FW. The phosphate uptake mechanism. PLANT SOIL. 2002, 245, 105-114.

4. Bao S. Soil Agro-chemistrical Analysis. China agriculture press: Beijing, China; 2000.

5. Brookes PC; Powlson DS; Jenkinson DS. Measurement of microbial biomass phosphorus in soil. SOIL BIOL BIOCHEM. 1982, 14, 319-329.

6. Wang Q. Study on the biological mechanism of phosphorus release from sediments in the shallow lakes. NORTHWEST A & F UNIVERSITY. 2006. Yangling, China.

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Simulation of Nutrient Input Process of the Yalu River under the Influence of Ocean Currents

Xuerong Wu1,* 1 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Xuerong Wu, [email protected]

Keywords: The Yalu River estuary Nutrient Model MIKE 21

1. Introduction

The MIKE 21 hydrodynamic module was combined with the Eco-lab eutrophication ecological module to establish a two-dimensional hydrodynamic and water quality model for the Yalu River input process. The nutrient transfer and diffusion in the North of the Yellow Sea and the Yalu River estuary were numerically simulated, and the horizontal distribution characteristics of nutrients and seasonal trends were obtained. This research provides a theoretical method for studying the effects of nutrient transport and diffusion on the typical biological population of the Yellow Sea, and helps to improve the ecological environment quality of the Yellow Sea.

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Sponge City-a Solution to Urban Water Management for Asian World

Mehvish Manzoor1,* 1 Master Student at Environmental Engineering and Technology, China University of Geosciences 388 Lumo road, Wuhan, P. R. 430074, China * Correspondence: Mehvish Manzoor, [email protected]

Keywords: sustainable development, sponge city, ecosystem, flood.

1. Introduction

Asian cities are stressed with overpopulation due to migration. By 2050, it is estimated almost 70% people will move for urban life. This will lead to increase demand of water. Many cities around Asian region suffer water scarcity problem. Sponge City is the modern methodology proposed by China to promote sustainable development. Sponge city project is natural solution for water conservation. The project got motivation by different ventures for urban water management from UK, European countries, Australia and New Zealand. Sixteen cities were selected for sponge city project in 2015 to cope 60% rainfall of following cities. Major purpose for these projects is to restore and purify natural rainfall and decrease the drainage system asset. 6.9 billion RMB is being utilized every year for 16 initial projects. Monsoon rainfall is the main cause of flood in Asian countries which affect millions of people every year. Apart from that climatic changes lead to the melting of glaciers and ice caps in Pakistan in results destruction of food crops every year. To manage these climatic disputes, Sponge City Project is basic need to save natural water for future generation which at present is appearing as human enemy in the form of floods. By implementing this project other Asian cities also enjoy the availability of clean water.

2. Methodology

Sponge city concept defines a city that behaves like a sponge with ability to absorb, clean and reuse water as a result of rainfall. Natural precipitation can collect by permeable roads (bricks pavement), Green spaces, Gardens, artificial wetlands and bio swales. For sponge city, abundant space is required to absorb water underground. More open green spaces, interconnected water channels across neighborhood are needed to clean water and save urban ecosystem. Greener roof are needed to filter the water before reuse. By implementing this project other Asian cities also enjoy the availability of clean water. Apart from that people can enjoy more green area to mentally relax and enjoy the fresh air from green spaces and last but not least it results in the reduction of flood rate and save water. This urban water management project gained positive results in reduction of floods in china territory, likewise can be implemented to other Asian cities.

3. Results and Discussion 144

This is a secondary data based research, collected through reports, research journals, project reports, newspapers and interview. This paper carries imperial analysis based on qualitative research and investigates Sponge City projects around China, implementing this methodology for other Asian cities and how far this methodology can be adapted to create more sponge cities all around Asia to produce water supply catchments. Many challenges are on the way to implement this methodology, the top two are the economic and political challenges for the Government. Government should work best to face all these challenges to save world from water based war.

4. Conclusions

It is a great opportunity for me to write on this research topic. I acknowledge with gratitude to my Respected Professor Hongchen Jiang who has always been sincere to me and helpful to understand things more clearly. I also acknowledge my colleague Mr. Sanwal Hussain Kharl for supporting me for writing this paper.

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Stormwater Ammonia Removal Ability in Bioretention and Grass Swale Using Source Loading and Management Model

Yuqi Li1, Xiaohua Yang2,*, Xiaojuan Chen2 1 Department of Urban Design and Planning, University of Washington, Seattle 98105, USA 2 School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: Xiaohua Yang, [email protected]

Keywords: stormwater; urban watershed; WinSLAMM; ammonia removal; bioretention

1. Introduction

Severe water pollution such as stormwater ammonia pollution is gaining more attention under rapid urbanization [1], and low-impact development (LID) strategies have become efficient for treating water pollution [2,3]. LID strategies such as bioretention and grass swale are effective for treating stormwater individually, but little is known about the impact of both configuration and coverage of LID strategies on pollutant removal ability. To control water pollution through LID strategies, this paper stimulated stormwater ammonia removal ability in designed scenarios of bioretention and grass swale under 10% ammonia reduction goal on an urban watershed planning scale. Then a decision support system (DSS) is developed to help determine the future bioretention and grass swale design to achieve ammonia reduction goal. Importantly, this study provides an urban watershed-scale scenario design strategy and a decision support system that will help design LID scenarios and provide LID arrangement recommendations to achieve water pollution controlling goal.

2. Methodology

The study site is 1.0 km2 Beijing Normal University (BNU). Using Source Loading and Management Model (WinSLAMM), ammonia reduction rate of the study site was calculated and analyzed under six bioretention design scenarios (4-64 per site; covering 7.5-20% of the site) and one grass swale design scenarios (arranged at one side of the road).

3. Results and Discussion

The results showed that the 10% ammonia removal target was met by four large consolidated bioretentions covering 7.5% of the site, and by consolidated or dispersed bioretentions covering 20% of the site, and by grass swale arranged along the road side. Therefore, consolidated ones could be more efficient in ammonia removal than dispersed ones. And configuration of bioretention landscapes appear to be more important than total coverage area in terms of ammonia reduction efficiency.

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By comparing one large bioretention arranged at the outlet of each of the four drainage area, and 100 small bioretentions dispersed on the site, we found that the ammonia removal efficiency of the larger bioretention scenarios were much more better than those scenarios with small bioretentions with same configuration. To further understand ammonia reduction efficiency under different bioretention arrangements, number and sizes, we propose three ammonia removal models: constant, power-exponent and inverse proportional function model for consolidated, tandem arrangement and parallel arrangement scenarios, respectively. As the number of bioretention increases, the ammonia removal rate of the tandem model is close to (1-e-b), and the parallel model is close to 0 (b is the ammonia removal capacity of one consolidated bioretention). We conclude that the sorting of the ammonia removal efficiencies of different bioretention configurations is: consolidated > tandem > parallel.

4. Conclusions

The stormwater ammonia reduction goal can be creatively achieved with diverse, realistic configurations of LID strategies like bioretention and grass swale, which also provide enhanced aesthetics, recreation opportunities, and other benefits beyond water quality.

5. Acknowledgement

This work was supported by the National Natural Foundation of China (No. 51679007), and the National Key Research Program of China (No. 2017YFC0506603).

References

1. Yu, C.; Huang, X.; Chen, H.; Godfray, H.C.J.; Wright, J.S.; Hall, J.W.; Gong, P.; Ni, S.; Qiao, S.; Huang, G.; et al. Managing nitrogen to restore water quality in China. Nature 2019, 567, 516.

2. Xu, Z.; Xu, J.; Yin, H.; Jin, W.; Li, H.; He, Z. Urban river pollution control in developing countries. Nat. Sustain. 2019, 2, 158.

3. Li, N.; Qin, C.; Du, P. Optimization of China Sponge City Design: The Case of Lincang Technology Innovation Park. Water 2018, 10, 1189.

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The Efficiency of Constructed Wetlands Systems for Wastewater Treatment SANJRANI M. A.1, ZHOU B., ZHAO H., ZHENG YP., WANG Y., and XIA, S. B.* 1 School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, P.R. China * Correspondence: XIA, S. B., [email protected]

Keywords: Constructed wetlands, waste water treatment, removal mechanisms, removal of pollutants, plants in wetlands

1. Introduction

Water issues are still there, urbanization and industries generate different types of waste which then affect water. Many technologies have been introduced for water treatment and efforts are being made to improve and maintain water quality, while also providing easily available and low-cost technologies. With its biological, physical and chemical treatment with water, constructed wetland technology becomes the best choice by many countries around the world. Existing research shows that COD, BOD5, TKN, TSS etc. have been removed significantly at a considerable level by using constructed wetlands. The role of plants in wetlands and the efficiency of the wetland system is reviewed in this paper.

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The Method Based on Cloud Service of Flood Forecast

Sihua Lei1,2,*, Ming Chen1,2 1 Nanjing Hydraulic Research Institute 2 The Key State Laboratory of Water Resource and Hydraulic Engineer Sciences * Correspondence: Sihua Lei, [email protected]

Keywords: cloud service; OpenMI; flood forecast; real-time imitate

1. Introduction

Flood forecast has been widely used in reservoirs, rivers and basins at different scales. As usually, prediction calculation and information service is completed on a single computer, which is called single computer mode. Another model is that both computing and information services are performed by servers, but computing is an independent program. The computing program obtains control information through external files or database. This mode can be called pseudo WebService. In this mode, computing and system expression are separated, and there are some risks such as inconvenience of system transplantation, delay of state variable information, and conflict-prone control. In order to solve these shortcomings, the cloud service scheme provided by us can realize the integration of flood forecasting model and information service system, facilitate system deployment, realize multi-user remote use and remote control.

2. Methodology

According to the technical implementation framework, cloud service scheme is divided into four parts: model interface design, model integration development, control information storage design and implementation, remote control process design and development. Among them, the design of model interface needs to complete components that can meet the integration of Internet Application System, which is the basis of remote control. The model developer completes the development of model computing engine according to the interface designed. OpenMI technology (open model interface technology) [1]is used to realize communication between models in this scheme. According to OpenMI Interface Specification, I/O Interface of Computing Engine (Computing Core of Model) is compiled. In this way, the input and output information of the model can be exchanged in the calculation process, and the efficiency and security of I/O can be improved. Assemble the model computing engine in the model integration development, that is, refer to the computing engine and use it as a component in the development instead of calling independent computing software. Model state information and trigger switch variables are the basic components of control information, generally including operation status, occurrence time, operator and other 149

information. In this scheme, the control information is stored and managed by database, and the information table of model running state is established. The basic process of remote control consists of forecasting parameter management, timing forecasting setting and automatic loading forecasting calculation. After the automatic loading and forecasting calculation is started, all calculation stages are executed on the server side, and after each calculation cycle is completed, the next prediction cycle will be automatically started according to the set calculation time.

3. Results and Discussion

This scheme is a remote control method for flood forecast calculation based on network. It supplies the method of unified operation of model calculation control and model state reading and writing in browser/server mode, and the calculation process of remote tracking model. It realizes dynamic display of model calculation process, can store all control operation commands, and the operation log of model calculation. It realizes the traceability of calculation operation and facilitates the tracking of calculation results. The characteristics of the mode include the following steps: step 1: design the model interface, including the external interface of the model calculation process and the interface between the models; step 2: integrated development of the model; step 3: design the control information of the model and store the control information; step 4: design and develop the remote control process.

4. Conclusions

The scheme has been applied in flood forecast of Shilianghe Reservoir in Jiangsu Province. After deployment at the server, it can be used by many kinds of managers, such as reservoir dispatching, forecasting scheme compilation, etc., and each user can complete all kinds of functions only by using browser on the client side, which does not conflict with each other. The scheme realizes the cloud service of forecasting and computing.

5. Acknowledgement

Many experts and business units have supported the research, development and implementation of this scheme. In particular, we need to thank Jiangsu Water Conservancy Department, Shilianghe Reservoir Management Institute.

References

1. Sihua Lei. Universal Model Interface for Time Series Computing OpenMI Development Technology and Application[M]. Beijing: China Water Resources and Hydropower Press. 2011.

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The Study on the Effect of Different Water Intake Methods of Large-scale Reservoirs on Fish Habitat

——A Case Study of Jiayan Water Control Project in Guizhou Province

Weizhu Deng1,*, Zhiyuan Fu, and Xiaoyu Huang 1 Scientific Institute of Pearl River Water Resources Protection * Correspondence: Weizhu Deng, [email protected]

Keywords: large-scale reservoir; low-temperature water; environment; influence

1. Introduction

The construction of large-scale reservoir projects has a significant effect on the environment of reservoir area and lower reaches stream. The establishment of dam has transformed the natural river with fast flow and uniform water temperature into relatively static large-scale water bodies. By solar radiation, convection mixing and heat transmission, the water temperature in the reservoir area appears vertical thermocline distribution, a lower temperature in bottom water than natural water [1]. The traditional single-layer water intake method will cause the reservoir discharge temperature to be lower than the natural water temperature of the river in summer, and higher than the natural water temperature in the river in winter. The low-temperature water discharged from the reservoir will have a significant negative effect on the reproductive growth of downstream aquatic organisms. Under the background of green development, low-temperature discharge water has become one of the important environmental problems caused by the construction of water resources and hydropower projects [2]. In the case of clear water temperature stratification, taking necessary engineering measures is an effective measure to mitigate the negative effects of low-temperature water discharged from reservoirs on the environment and ecology [3]. Taking Jiayan Water Control Project in Guizhou Province as an example, the water temperature distribution was obtained by the three-dimensional numerical simulation, so as to study the effect of different water intake methods of large- scale reservoirs on downstream fish habitat.

2. Methodology

Reservoir capacity ratio method and Froude number method were adopted to judge water temperature structure in reservoir area. The three-dimensional numerical model was established to predict the vertical water temperature in Jiayan Reservoir which took into account the model validation by the measured water temperature data of the downstream Hongjiadu Reservoir. Hongjiadu Reservoir, the first reservoir in cascade reservoirs of Wu River, is located in the lower reaches of the proposed Jiayan Reservoir. After validation,

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the model was used for water temperature prediction of Jiayan Reservoir. On the basis, there were the further analysis on the vertical structure of water temperature of Jiayan Reservoir, and the influence of low-temperature water.

3. Results and Discussion

The vertical water temperature of Jiayan Reservoir was stratified stably. The range of temperature between surface and bottom layer varied obviously with seasons. The surface water temperature mainly depended on light intensity, and the bottom water temperature was relatively stable. The temperature difference between the discharging water and natural water was -3.7~1.3 ℃ under single-layer water intake method, and that between discharge water and natural water was -2.5~1.1 ℃ under stratified water intake method. The stratified water intake method could effectively improve the discharge water temperature in summer, reduce the temperature difference between the discharge water and natural water, shorten the recovery distance of the low-temperature discharge water, and alleviate the negative effect on the fish habitat in the downstream.

4. Conclusions

The negative ecological environment influence caused by low-temperature water discharged from large-scale water reservoir project were alleviated effectively, which has important environmental benefits.

5. Acknowledgement

This work was supported by Jiayan Water Control Project and Northwest Guizhou Water Supply Project for data supply.

References

1. Liu LF. Impacts of hydropower development on river basin environment. Journal of Hydraulic Engineering. 2002, 33(8): 121-128.

2. Qi CJ, Chen KQ, Cao XH et al. Prediction of Impact on Water Temperature by Hydraulic and Hydro-power Engineering and Key Points in Technical Review. Environmental Impact Assessment. 2016, 38(3): 1-4.

3. Zhang SJ, Liu CM, Tan HW et al. Effect of low temperature on reservoir water and mechanical control measure. Chinese Journal of Eco-Agriculture. 2011, 19(6): 1412-1416.

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Uncertain Power from Shallow Flow

Monika J. Kreitmair1, Alistair G. L. Borthwick1,2,*, and Ton S. van den Bremer3 1 School of Engineering, The University of Edinburgh, Edinburgh, U.K. 2 St Edmund Hall, Queen’s Lane, Oxford OX1 4AR, U.K. 3 Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, U.K. * Correspondence: Alistair Borthwick, [email protected]

Keywords: uncertainty propagation; shallow flow; bed roughness; hydropower

1. Introduction

In numerical models of physical systems, such as shallow flow solvers, uncertainty arises from inexact specification of the environment, physical and numerical model parameters, and model assumptions. By assigning probabilities to input variables, uncertainty may be quantified as it propagates through a model. In hydraulic engineering, shallow flow solvers are routinely used to predict hydrodynamics, sediment transport, and water quality in rivers, lakes, and coastal basins. Such solvers are also commonly applied to hydropower estimates, considered herein. An important source of uncertainty comes from the value assigned to the bed roughness coefficient. In practice, the exact bed conditions of a shallow flow domain are unknown, in particular the texture or roughness of the bed surface. Many modelers simply use the bed roughness coefficient as a tuning parameter, often applied with a uniform value throughout the domain (e.g. [1]) even though bed conditions vary from smooth surfaces, to sand, to rocks, to vegetation, with bedforms. The unknowns in bed roughness therefore affect hydropower estimates. This paper considers uncertainty propagation through an idealized model of hydropower extraction from steady flow in a wide channel. We examine how uncertainty, expressed as a fluctuation about a mean value in bed coefficient, influences the expected power and its variance.

2. Methodology

The river is idealized as a one-dimensional channel, with flow driven by a constant head difference, and an analytic solution for power derived in terms of the bed roughness

coefficient, Cd. Three methods are presented (following [2, 3]) for determining the propagation of uncertainty in bed friction to uncertainty in power: (1) transfer of a

probability density function (PDF) in Cd through the closed-form analytic solution for power; (2) the numerical equivalent PDF transfer; and (3) an approximate, perturbative method where power is expressed as a Taylor expansion, resulting in leading-order expressions for the statistical moments for power. Further, a numerical model based on the shallow water equations is used to determine the expected power and its standard deviation. Results from the numerical model are compared to those from the expansion method applied to the closed-form solution to explore the impact of having only an approximate knowledge of the functional dependence of power on bed roughness.

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3. Results and Discussion

A truncated normal distribution is used as input distribution for Cd. PDFs of power generated from the different PSF transfer methods exhibit near perfect agreement for

specified input PDFs of Cd. A comparison is also made between power statistics determined from the expansion method and the PDF transfer method. The results show, provided the power surface is sufficiently well captured by a closed-form solution, that the expansion technique gives a satisfactory, leading-order estimate for the effect of bed roughness uncertainty on power estimates though a slightly less accurate estimate of the standard deviation. Results are also presented from a parameter study of the effect of uncertainty in natural bed roughness on power extracted from a horizontal channel of length 20 km and mean depth 50 m. It is found that uncertainty acts to increase estimates of the mean power. In general, the expansion method slightly underestimates the relative change in expected power at low values of turbine drag. The expansion method is able to capture trends in impact of uncertainty in bed roughness coefficient on power, particularly for low

values of input ratio of standard deviation to mean Cd.

4. Conclusions

An analytic model, derived for power dissipated by a patch of enhanced friction in a one- dimensional channel, has been used to compare three methods for uncertainty propagation from an input PDF in bed roughness coefficient to expected power and the standard deviation in power. The results from these methods are remarkably similar. Of the three methods, the numerical method is of particular interest because as a technique it could have broad applicability in hydraulic engineering, for example in flood estimation or sediment transport calculations.

References

1. Adcock T.A.A.; Draper S.; Houlsby G.T.; Borthwick A.G.L.; Serhadlıoğlu S. The available power from tidal stream turbines in the Pentland Firth. Proc. Roy. Soc. A 2013, 469, 20130072.

2. Kreitmair M.J. Uncertainty quantification in tidal energy resource assessment. PhD Thesis, University of Edinburgh 2018.

3. Kreitmair M.J.; Draper S.; Borthwick A.G.L.; van den Bremer T.S. (2019) The effect of uncertain bottom friction on estimates of tidal current power. Roy. Soc. Open Sci. 2019, 6(1), 180941.

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Water Quality Assessment of Qingpu District, Shanghai Based on Logistic Set Pair Analysis Model

Yukun Luo1, XiaoHua Yang1,*

1 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China * Correspondence: XiaoHua Yang, [email protected];

Keywords: water quality assessment; Logistic Set Pair Analysis Model, Qingpu District

1. Introductio

The optimal quantity and acceptable quality of water is one of the essential needs for the survival of mankind on the Earth [1]. The water environment is an important part of the human settlements, especially in areas with developed water networks, such as Qingpu District, Shanghai. Logistic set pair analysis model, combining Logistic theory with set pair analysis theory, was applied to the assessment of water resources carrying capacity in Jilin Province [2]. In this study, the Logistic Set Pair Analysis Model (LSPAM) was used to assess water quality in Qingpu District, Shanghai.

2. Methodology

The main water quality data was collected and tested in Qingpu District in April 2019. The index includes DO, NH3-N, TP, BOD5, CODMn, NO3--N, SS, Cu, Zn, Pb, Cr, Hg and FC (Fecal Coliform) [3]-[5]. First, this study builds a multiple contact based on set pair analysis theory:

5*1+0I1+0I2+0I3+0J, x>s4 5*(1-v2)+4*v2I1+0I2+0I3+0J, s3

where ui,j is the score of sample i on indicator j.

Second, connection number v is calculated with Logistic Model: √3 1 √3 푣 = + − (2) 푘 1.317(푠푘+푠푘−1−2푥) 2 2 1+푒 푠푘−푠푘−1

푣푘−1 = 1 − 푣푘 (3)

Third, water quality assessment comprehensive score is calculated: 푗=12 푢푖 = ∑푗=1 푢푖,푗 (4)

3. Results and Discussion

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Sample 1 2 3 4 5 6 7 8 9 10 11 Score 43.18 41.12 39.44 36.58 35.44 34.44 33.28 33.36 31.76 31.28 34.84 rank Ⅲ Ⅲ Ⅲ Ⅳ Ⅳ Ⅳ Ⅳ Ⅳ Ⅳ Ⅳ Ⅳ The results showed that 3 of the 11 samples taken belonged to Ⅲ and the rest belonged to Ⅳ. The main pollutants were ammonia nitrogen (NH3-N) and total phosphorus (TP). From the test data, DO index is concentrated in Ⅲ and Ⅳ, NH3-N and TP index are concentrated in Ⅲ and Ⅴ, COD index is concentrated in Ⅲ.

4. Conclusions

The evaluation results of LSPAM are similar to those of the Shanghai Water Environment Monitoring Center, which indicates that the model is effective. Besides, local government needs to analyze the source of water pollution, focusing on remediation of water quality in the eastern region.

5. Acknowledgement

References

1. Shrikant M, Vasant W, Dipak P. Development of new integrated water quality index (IWQI) model to evaluate the drinking suitability of water. Ecological Indicators. 2019, 101, 348-354.

2. Tong Liu, Xiaohua Yang, Fan Song. Logistic set pair analysis model for water resources carrying capacity assessment and its application. Journal of North China University of Water Resources and Electric Power (Natural Science Edition). 2019, 40(01), 27-33.

3. Yulu T, Yuan J, Qi L, Manyu D, Dingxue X. Using a water quality index to assess the water quality of the upper and middle streams of the Luanhe River, northern China. Science of The Total Environment. 2019, 667, 142-151.

4. Mei X, Ruili R, Maosong L. Annual changes of water quality in a upstream river of Taihu Lake. Journal of Nanjing Forestry University (Natural Science Edition). 2007, 31(06), 121-124.

5. Chengcheng L, Xubo G. Assessment of Groundwater Quality at Yuncheng Basin: Denotation for the Water Management in China. Groundwater, 2019, 57(3).

156

Water Quality Evaluation of the Hong Lake Based on the Water Quality Index Method

Libin Chen1,2,*, Zhou Tian1, Linwei Dong1, Yaolong Zhang1, Kaipeng Zou3, Pingchuan Yang3 1 College of Resources and Environment, Yangtze University, Wuhan 430100, China 2 International Institute of Aquatic Ecology, Yangtze University, Wuhan 430100, China 3 Bureau of Hydrographic and Hydrographic Resources Survey, Jingzhou City, 434000, China * Correspondence: Libin Chen, [email protected]

Keywords: Hong Lake; Water quality assessment; Water quality index method; Heavy metal; Yangtze River Economic Zone

1. Introductio

Hong Lake is the largest lake wetland in the Hubei Province and one of the largest lakes in the Yangtze River Economic Zone as well. It is a multi-functional lake mainly responsible for water resources storage. Hong Lake has performed as an important wetland for years since that many aquatic animals and plant resources inhabit in the lake. However, the water quality of the Hong Lake tends to deteriorate in the recent decades, owing to the rapid development of social and economy in the watershed with unreasonable human activities, such as lake enclosure culture. Based on the water quality index (WQI) method, the water quality monitoring data of five observation sites in the recent 10 years were analyzed and evaluated. The results show that the water quality of the Hong Lake was ascribed to the "General" grade with the WQI being 43.41±6.66. However, after going through a decade-long increasing deterioration, the water quality tends to be improved in the recent two years. The water quality sampling sites of the Hong Lake are the Lantian, the Dakou, the Shidun estuary, the Chatan Island and the Guandun Island. The worst and the best water quality are located at the sampling sites of the Lantian and the Guandun respectively. The water quality index adopted in this study has three sub-indexes, which are the refractory toxicity indexes, the easy purify pollution indexes and the other indexes. The refractory toxicity indexes are the ρ(As), ρ(Hg), ρ(Cd), ρ(Cr), ρ(Pb) and ρ (Se), which played a leading role in the WQI. Among those heavy metal indexes, the ρ(Pb) and the ρ(Cd) are the key parameters to determine the water quality of the Hong Lake. Therefore, the investigation and evaluation of the heavy metals in the lakes should be paid more attention in the future.

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Address No.18 Wangzhuang Road, HaiDian District, Beijing, China

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Beijing West Railway Station (16km) Take bus No.387/21 to Suojiafen station and transfer bus No.375/562 to Beijing

Language and Culture University.

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II. Contact Liming Xing (Secretary-General) Xuerong Wu (Secretary-Registration)

Tel: +86-18849448339 Email: [email protected]

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