Combined Impacts of Sand Mining Activities: The Nandu River Downstream Segment

2013 ◽  
Vol 671-674 ◽  
pp. 3134-3137 ◽  
Author(s):  
Shu Wei Jiang ◽  
Abuduhelili Haibier ◽  
Yong Xin Wu
Keyword(s):  
Water Environment ◽  
Aquatic Organisms ◽  
Field Investigation ◽  
Hydrodynamic Characteristics ◽  
Social Stability ◽  
Mining Activities ◽  
Sand Mining ◽  
Natural Evolution ◽  
River Sand ◽  
Downstream Section

With the accelerated pace of urban construction in Hainan province, demand for building sand increased rapidly, river sand prices soared. This led to the illegal and unauthorized sand mining continue to emerge at Nandu River downstream segment. The current sand mining situation of Nandu River downstream section was expounded. The various impacts of sand mining activities on river regime, flood safety, hydrodynamic characteristics of the river, development of delta and water environment have been studied according to measured data and results of field investigation. It is shown that sand mining activities undermines the natural evolution of the river regime; affects the habitat of fish and other aquatic organisms. Water level drops, water velocity decreases, and the Nandu Rive delta coastline retrogrades due to sand extraction. Besides, sand mining has an obvious adverse impact on infrastructures, waterway safety and social stability.

Establishing an empirical equation for the relationship between total suspended solids and total phosphorus concentrations in the downstream Red river water

2020 ◽  
Vol 20 (3) ◽  
pp. 325-332
Author(s):  
Le Nhu Da ◽  
Le Thi Phuong Quynh ◽  
Phung Thi Xuan Binh ◽  
Duong Thi Thuy ◽  
Trinh Hoai Thu ◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Suspended Solids ◽  
Empirical Relationship ◽  
Water Environment ◽  
Total Suspended Solids ◽  
River System ◽  
Red River ◽  
Reservoir Impoundment ◽  
Downstream Section ◽  
Reasonable Prediction

Recently, the Asian rivers have faced the strong reduction of riverine total suspended solids (TSS) flux due to numerous dam/reservoir impoundment. The Red river system is a typical example of the Southeast Asian rivers that has been strongly impacted by reservoir impoundment in both China and Vietnam, especially in the recent period. It is known that the reduction in total suspended solids may lead to the decrease of some associated elements, including nutrients (N, P, Si) which may affect coastal ecosystems. In this paper, we establish the empirical relationship between total suspended solids and total phosphorus concentrations in water environment of the Red river in its downstream section from Hanoi city to the Ba Lat estuary based on the sampling campaigns conducted in the dry and wet seasons in 2017, 2018 and 2019. The results show a clear relationship with significant coefficient between total suspended solids and total phosphorus in the downstream Red river. It is expressed by a simple equation y = 0.0226x0.3867 where x and y stand for total suspended solids and total phosphorus concentrations (mg/l) respectively with the r2 value of 0.757. This equation enables a reasonable prediction of total phosphorus concentrations of the downstream Red river when the observed data of total suspended solids concentrations are available. Thus, this work opens up the way for further studies on the calculation of the total phosphorus over longer timescales using daily available total suspended solids values.

scholarly journals Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

2015 ◽  
Author(s):  
Xing Wang ◽  
Binghui Zheng ◽  
Lusan Liu ◽  
Lijing Wang
Keyword(s):  
Water Quality ◽  
Water Environment ◽  
Aquatic Organisms ◽  
Dongting Lake ◽  
Assessment System ◽  
Biotic Integrity ◽  
Diatom Index ◽  
Integrity Index ◽  
Biotic Integrity Index

<p>A Lake Multi-biotic Integrity Index (LMII) for the China’s second largest interior lake (Dongting Lake) was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diatoms, Margalef index of algae, percent sensitive diatoms, % facultative individuals, % Chironomidae individuals, % predators individuals, and total number of macroinvertebrate taxa. We then tested the accuracy and feasibility of the LMII by comparing the correlation with physical-chemical parameters. Evaluation of the LMII showed that it discriminated well between reference and impaired sections and was strongly related to the major chemical and physical stressors (r = 0.766, P&lt;0.001). The re-scored results from the 10 sections showed that the water quality of western Dongting Lake was good, while that of southern Dongting Lake was relatively good and whereas that of eastern Dongting Lake was poor. The discriminatory biocriteria of the LMII are suitable for the assessment of the water quality of Dongting Lake. Additionally, more metrics belonging to habitat, hydrology, physics and chemistry should be considered into the LMII, so as to establish comprehensive assessment system which can reflect the community structure of aquatic organisms, physical and chemical characteristics of water environment, human activities, and so on.</p>

Soil Moisture Retrievals in Aeolian Sand Mining Areas Using Temporal, Single-Polarization, High-Resolution SAR

Frequenz ◽  
2018 ◽  
Vol 72 (11-12) ◽  
pp. 547-560
Author(s):  
Wei MA ◽  
Chao MA
Keyword(s):  
Soil Moisture ◽  
High Intensity ◽  
Surface Soil ◽  
Absolute Error ◽  
Mining Activities ◽  
Approximation Model ◽  
Sand Mining ◽  
Surface Soil Moisture ◽  
Aeolian Sand ◽  
Sampling Points

Abstract Changes in the soil moisture are a key factor in the deterioration of the ecological environment caused by mining geological disasters. In this study, which presents a case study of the arid and semi-arid aeolian sand mining area along the Inner Mongolia-Shaanxi Province boundary, a method for retrieving the soil moisture based on RADARSAT-2 SAR scattering data and Terra MODIS surface reflectance data was proposed. The retrieval of RADARSAT-2 mainly used the Alpha approximation model based on the change detection technique, a model proposed by Balenzano et al., which can effectively decouple the impact of surface vegetation and roughness on radar backscattering coefficient, when the volume scattering is not dominant. Using 12 periods of RADARSAT-2 HH polarization data in conjunction with the Alpha approximation model, a matrix equation was constructed, which contains 11 equations and 12 unknowns. To solve this underdetermined system, a bounded linear least-squares optimization was adopted. Once the unknowns were determined, the relative dielectric constant could be analytically derived and then the soil moisture could be estimated by using the dielectric mixing model and compared with the MODIS retrieval results based on the spatial feature method. Finally, the DInSAR results of RADARSAT-2 were used to investigate the effects of high-intensity underground mining activities on the surface soil moisture. The study found that the RADARSAT-2 soil moisture estimates demonstrated good consistency with the MODIS retrieval results. Among four comparison groups, the maximum correlation coefficient was 0.599, and the highest proportion of sampling points for which the absolute error was less than 3 % was 55.6 %. The absolute error of all of the sampling points did not exceed 10 %, which demonstrates the reliability of the RADARSAT-2 retrieval results. A comparison among the 72 soil moisture values from six mining subsidence areas and corresponding non-subsidence areas in the study area in 2012 showed that 38 soil moisture values from the non-subsidence areas were higher than those from the subsidence areas. These values accounted for 53 % of the total, indicating that high-intensity mining activities have a certain negative impact on the surface soil moisture, although this impact is slightly insignificant.

Evaluation of infilling and replenishment of river sand mining pits

2020 ◽  
Vol 79 (14) ◽  
Author(s):  
Hamed Haghnazar ◽  
Yousef Sangsefidi ◽  
Mojtaba Mehraein ◽  
Hassan Tavakol-Davani
Keyword(s):  
Sand Mining ◽  
River Sand

scholarly journals Seismic Exploration of the River Sand Mining Area

2019 ◽  
Vol 252 ◽  
pp. 052028
Author(s):  
Jian Zhang ◽  
Lei Fang ◽  
Yanhai Wang ◽  
Jun Mei
Keyword(s):  
Mining Area ◽  
Seismic Exploration ◽  
Sand Mining ◽  
River Sand
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