scholarly journals Traceability and Emission Reduction of Dissolved Inorganic Nitrogen in Minjiang Estuary, China

2021 ◽  
Vol 18 (19) ◽  
pp. 10017
Author(s):  
Chenchen Fan ◽  
Peng Zhang ◽  
Gangfu Song ◽  
Huaru Wang ◽  
Bingyi Wang
Keyword(s):  
Water Quality ◽  
Inorganic Nitrogen ◽  
National Standards ◽  
Dissolved Inorganic Nitrogen ◽  
Quality Model ◽  
Model Calculations ◽  
Minjiang River ◽  
Global Environmental ◽  
Near Shore ◽  
Coefficient Method

The accumulation of dissolved inorganic nitrogen (DIN) in estuaries has become a global environmental problem. A two-dimensional, hydrodynamic water quality model was constructed in this study to investigate the sources of DIN pollution in the Minjiang Estuary. The concentration response field between the stream input and DIN in the estuary was established by using the surveyed source data of the study area. A sharing coefficient method was used to calculate the contribution percentage of each outfall to derive and propose a reasonable nitrogen reduction plan. The results showed that the input of land-based nitrogen into the Minjiang River contributed more than half of the DIN in the near-shore sea; the middle and upper reaches of the Minjiang River largely influenced the estuary area (38.57%). Conversely, the estuary and the coastline accounted for a smaller proportion of only 5.24%, indicating that an integrated DIN reduction should be implemented in the estuary area of the whole river basin. The model calculations showed that the reduction results, after remediation according to the current national standards for wastewater discharge in rivers, were not satisfactory. Thus, a new scheme is proposed in this paper—the total nitrogen (TN) input from land-based sources into the Minjiang Estuary and from the Shuikou Dam to the Min’an section should be reduced to below 31.64%; simultaneously, the DIN concentration discharged from the Shuikou Dam should be controlled and maintained below 0.5 mg·L−1 (TN = 0.8 mg·L−1). These results will provide guidelines for developing strategies for the improvement of DIN and water quality in similar estuaries.

Impact of Further Impoundments on the Oxygen Balance and Water Quality of the Danube in Germany

1990 ◽  
Vol 22 (5) ◽  
pp. 69-78 ◽  
Author(s):  
D. Müller ◽  
V. Kirchesch
Keyword(s):  
Water Quality ◽  
Quality Parameters ◽  
Nitrifying Bacteria ◽  
Oxygen Balance ◽  
Quality Model ◽  
Model Calculations ◽  
River Bed ◽  
The Impact ◽  
The Mathematical Model

The construction of two or three impounding dams in the remaining freely flowing reach (73 km) of the Danube is under discussion. The purpose of these impoundments is to guarantee a minimum navigable depth of 3 m needed for modern cargo ships and to produce electric power. The impact of these developments is discussed on the basis of experience with similar impoundments further upstream and of the results from water quality model calculations. The mathematical model used is of the deterministic type, calculating the growth of slowly-growing organisms (nitrifying bacteria, algae and zooplanktons) according to MONOD and MICHAELIS-MENTEN. Compared with impoundments on other German rivers or the Iron Gate impoundments on the Danube, the effect of the impoundments under discussion on water quality parameters is likely to be fairly small, reflecting the slight changes in morphology which would be necessary for attaining the water depth required. Therefore, the more important effects of these developments would be the changes in the ecologic situation at the river bed and near the banks of the river.

scholarly journals Influence of Riverbed Incision and Hydrological Evolution on Water Quality and Water Age Based on Numerical Simulation: A Case Study of the Minjiang Estuary

2021 ◽  
Vol 18 (11) ◽  
pp. 6138
Author(s):  
Peng Zhang ◽  
Lanyimin Li ◽  
Yishu Wang ◽  
Chengchun Shi ◽  
Chenchen Fan
Keyword(s):  
Water Quality ◽  
Dilution Effect ◽  
Scientific Basis ◽  
Low Oxygen ◽  
Quality Model ◽  
Water Age ◽  
Offshore Water ◽  
Minjiang River ◽  
Open Sea ◽  
Pollutant Discharge

In recent years, problems such as water quality deterioration, saltwater invasion, and low oxygen have appeared in estuaries all over the world. The Minjiang River in Fujian, as a typical tidal estuary area, is facing these thorny problems. In this paper, the effects of topography and hydrologic evolution on the water age and water quality of the lower reaches of the Minjiang River were simulated by building a hydrodynamic and water quality model. The results show that: (1) It was found that the riverbed incision of the lower reaches of the Minjiang River led to the overall decline of river water level, the increase of river volume, and the increase of downstream water age, which eventually led to the decrease of dissolved oxygen (DO) and the deterioration of water quality in the downstream from Shuikou to Baiyantan. However, the decline of topography led to the increase of tidal volume in the estuary, the enhancement of the dilution effect of oxygen-rich water bodies in the open sea, and the increase of DO in the lower reaches of Baiyantan. (2) Under no tidal action, the concentration of pollutants in the water of the North Channel increased, the DO decreased, and the DO decreased from Baiyantan to the offshore water. After the enhancement of tidal action, the dilution of oxygen-enriched water from the offshore water increased, and the DO increased. (3) The hydrological and water quality characteristics of the upper part of the lower reaches of the Minjiang River were mainly controlled by topography, runoff, and pollutant discharge, which were more affected by the tidal current transport operation and pollutant discharge near the open sea. In recent decades, the deterioration of water quality and the aggravation of saltwater intrusion in the Minjiang River were closely related to the serious topographic downcutting. The results provide a scientific basis for revealing the deterioration of estuary water quality and long-term management of the estuary.

scholarly journals Analysis on the Evolution Trend of Seawater Quality and Eutrophication in Tianjin Hangu Agricultural and Fishery Area from 2010 to 2019

2021 ◽  
Vol 245 ◽  
pp. 02024
Author(s):  
Yi Chen
Keyword(s):  
Water Quality ◽  
Pollution Control ◽  
Inorganic Nitrogen ◽  
The State ◽  
Dissolved Inorganic Nitrogen ◽  
Functional Area ◽  
Nitrogen And Phosphorus ◽  
Seawater Quality ◽  
Sea Area

Through the collection and analysis of COD, dissolved inorganic nitrogen (DIN) and active phosphate monitoring data in Tianjin Hangu Agricultural and fishery area from 2010 to 2019, this paper analyzed and studied the structure of nutrients and the state of eutrophication. The results show that in recent ten years, the water quality of Tianjin Hangu Agricultural and Fishery Area has basically met the water quality requirements of functional area, the regional nitrogen pollution has been suppressed, and the eutrophication index of sea area has shown a decreasing trend year by year, but the nitrogen and phosphorus nutrient structure is still in the state of “phosphorus restriction”. Pollution control of sea areas and conservation of aquatic germplasm resources are still urgent.

Characteristic and Influential Factors of Pollution Zone in the Lower Reach of Minjiang Tidal River

2011 ◽  
Vol 403-408 ◽  
pp. 2437-2440
Author(s):  
Mei Bing Liu ◽  
Xing Wei Chen
Keyword(s):  
Water Quality ◽  
Influential Factors ◽  
Tidal River ◽  
Two Dimensional ◽  
Lower Reach ◽  
Quality Model ◽  
Longitudinal Diffusion ◽  
Pollutant Load ◽  
Minjiang River ◽  
Tidal Area

The lower reach of Minjiang River, which passes through the Fuzhou city, is in the tidal area. A Two-Dimensional hydrodynamic and water quality model is developed. Taking Wukong sewage outfall as an example, the characteristic of pollution zone which is visualized by the contour of concentration is investigated, and the influential factors are also analyzed. It shows that the longest upstream pollution zone appears near the fastest flood moment, the longest downstream one appears near the ebb moment, the widest pollution zone occurs near the high or low water stand moment. The factors such as pollutant load, pollutant decaying coefficient and longitudinal diffusion coefficient are sensitive to the range of the pollution zone.

scholarly journals Reef exposure to river-borne contaminants: a spatial model

2009 ◽  
Vol 60 (11) ◽  
pp. 1132 ◽  
Author(s):  
M. Maughan ◽  
J. Brodie
Keyword(s):  
Water Quality ◽  
Quality Improvement ◽  
Great Barrier Reef ◽  
Inorganic Nitrogen ◽  
Suspended Sediments ◽  
Barrier Reef ◽  
Dissolved Inorganic Nitrogen ◽  
Water Quality Improvement ◽  
Management Board ◽  
Contaminant Load

Rivers flowing into the Great Barrier Reef carry contaminants such as suspended sediments, dissolved inorganic nitrogen, total phosphorus and pesticides. To measure the extent and direction of the contaminants after they enter the Great Barrier Reef lagoon, a model was created using river volume, flooding variability, contaminant load, distance and direction as inputs. A GIS was used to calculate and visualise the exposure of the contaminants to the reefs for the current day, as well as modelling scenarios for pre-European arrival loads, and land management using realistic targets set by a regional Natural Resource Management board for water quality improvement planning purposes. The results show that a reduction in the dissolved inorganic nitrogen load exiting the Tully and Murray Rivers reduces the exposure of reefs close to the basin, but that reefs further east of the basin are significantly influenced by other rivers, highlighting that management for water quality improvement in neighbouring basins is also required.

Distribution and Trend Analysis of DIN in Marine Environment Waters under Reclamation

2013 ◽  
Vol 864-867 ◽  
pp. 1000-1003 ◽  
Author(s):  
Ying Jie Zhao ◽  
Ming Chang Li ◽  
Guang Lou Li ◽  
Run Hong Jiao ◽  
Yuan Yuan Cao
Keyword(s):  
Water Quality ◽  
Environmental Management ◽  
Sustainable Development ◽  
Marine Environment ◽  
Inorganic Nitrogen ◽  
Grid Method ◽  
Dissolved Inorganic Nitrogen ◽  
Natural Neighbor ◽  
Fitting Method ◽  
Regional Sustainable Development

Marine environment is an essential aspect for the regional sustainable development. The distribution and trend of pollutant factors is a key guidance to environmental management. In this paper, the distribution and trend of dissolved inorganic nitrogen (DIN) in marine environment waters is researched for guiding and improve the environmental impact assessment in the Caofeidian marine district, Tangshan Bay. The natural neighbor grid method and the least squares fitting method are used for the distribution and the trend respectively. The research results show that the part of DIN exists exceeded forth level of water quality and the trend of DIN is on the rise in recently.

Mixed Layer Models and Their Application to Water Quality Problems

1994 ◽  
Vol 29 (2-3) ◽  
pp. 221-232
Author(s):  
M.J. McCormick
Keyword(s):  
Water Quality ◽  
Mixed Layer ◽  
Thermal Structure ◽  
Mass Conservation ◽  
Eddy Diffusion ◽  
Rate Of Change ◽  
Surface Mixed Layer ◽  
Storm Events ◽  
Quality Model ◽  
Mixing Processes

Abstract Four one-dimensional models which have been used to characterize surface mixed layer (ML) processes and the thermal structure are described. Although most any model can be calibrated to mimic surface water temperatures, it does not imply that the corresponding mixing processes are well described. Eddy diffusion or "K" models can exhibit this problem. If a ML model is to be useful for water quality applications, then it must be able to resolve storm events and, therefore, be able to simulate the ML depth, h, and its time rate of change, dh/dt. A general water quality model is derived from mass conservation principles to demonstrate how ML models can be used in a physically meaningful way to address water quality issues.

Applying the Soil Water Assessment Tool to 5th Canadian Division Support Base Gagetown

2014 ◽  
Vol 49 (4) ◽  
pp. 372-385
Author(s):  
Shawn Burdett ◽  
Michael Hulley ◽  
Andy Smith
Keyword(s):  
Water Quality ◽  
Soil Water ◽  
Land Management ◽  
Management Practices ◽  
Assessment Tool ◽  
Anthropogenic Activities ◽  
Quality Model ◽  
Sediment Yields ◽  
Soil Water Assessment Tool ◽  
Water Assessment

A hydrologic and water quality model is sought to establish an approach to land management decisions for a Canadian Army training base. Training areas are subjected to high levels of persistent activity creating unique land cover and land-use disturbances. Deforestation, complex road networks, off-road manoeuvres, and vehicle stream crossings are among major anthropogenic activities observed to affect these landscapes. Expanding, preserving and improving the quality of these areas to host training activities for future generations is critical to maintain operational effectiveness. Inclusive to this objective is minimizing resultant environmental degradation, principally in the form of hydrologic fluctuations, excess erosion, and sedimentation of aquatic environments. Application of the Soil Water Assessment Tool (SWAT) was assessed for its ability to simulate hydrologic and water quality conditions observed in military landscapes at 5th Canadian Division Support Base (5 CDSB) Gagetown, New Brunswick. Despite some limitations, this model adequately simulated three partial years of daily watershed outflow (NSE = 0.47–0.79, R2 = 0.50–0.88) and adequately predicted suspended sediment yields during the observation periods (%d = 6–47%) for one highly disturbed sub-watershed in Gagetown. Further development of this model may help guide decisions to develop or decommission training areas, guide land management practices and prioritize select landscape mitigation efforts.

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