Effect of seawater intrusion on groundwater in the Demak coastal area Indonesia: a review

One of the most complicated areas to repair on the North Shore of Central Java is the beach in the Sayung Demak. More than 300 hectares of land have been flooding in the last five years due to high tides. The erosion area in Sayung area has also been affected by port development activities in the Semarang area, thus changing the hydrodynamic nature of Sayung Demak Waters. Overuse of groundwater has been showing to lead to brine ingress in the coastal region. And long-term groundwater withdrawal forces land subsidence formation. A few waterfront structures in Sayung waters were built as breakwaters to decrease incoming waves. The solution presently used to minimize erosion while catching sediment in the Sayung area is hybrid engineering. The purpose of this study is to review the effectiveness of hybrid engineering in the coastal area of Demak and its relation to seawater intrusion and groundwater based on previous research. Understanding the factors that influence water quality in the source area over time is needed to establish appropriate management plans for the protection of groundwater resources and to ensure the safety and health of the beverage.

Numerical Simulation of Gas-Solid Two-Phase Erosion for Elbow and Tee Pipe in Gas Field

Erosion caused by solid particles in a pipeline is one of the main problems endangering the safety production of the oil and gas industry, which may lead the equipment to malfunction or even fail. However, most of the previous studies focused on the standard elbow, and the erosion law of right-angle elbow and blind tee is rarely reported in the literature. This work aims to investigate the erosion law of different pipeline structures including 90° elbow, right-angle pipe, and tee pipe based on the production characteristics and engineering parameters of the gas field. An integrated CFD-DPM method is established including a realizable k-ε turbulence model, discrete phase model, and erosion rate prediction model. The accuracy of the model is evaluated by a series of experimental data of flow conditions of our previous work. Further, the erosion rate, pressure distributions, and particle trajectories in 90° elbow, right-angle pipe, and tee pipe under different flow velocities, particle mass flow rate, pipe diameter are investigated by applying the presented model. The results show that the blind tee has the most obvious growth rate, and the most serious erosion is located in the blind end of the pipe wall. The maximum erosion rate of the 1.5D is greater than that of the 3D elbow as a whole, and the 1.5D elbow is more concentrated in the serious erosion area. Furthermore, the erosion rate of the bend weld is much greater than that of the straight pipe weld. This study can provide a basis for the selection of different structural pipe fittings, thereby reducing the pipeline erosion rate and improving the integrity of the management of gas pipelines.

Analysis of shoreline changes along the coast of Tiruvallur district, Tamil Nadu, India

Shore line change is considered as one of the most dynamic processes, which were mapped along the coast of Tiruvallur district by using topographic maps of 1976 and multi-temporal satellite images. The satellite images pertaining to 1988, 1991, 2006, 2010, 2013 and 2016 were used to extract the shorelines. It is important to map and monitor the HTL (High Tide Line) at frequent time intervals as the shoreline was demarcated by using visual interpretation technique from satellite images and topographic maps. Followed by this, an overlay analysis was performed to calculate areas of erosion and accretion in the study area. The results revealed that the coast of Tiruvallur district lost 603 ha and gained 630 ha due to erosion and accretion respectively. It was confirmed after the ground truth survey carried out in the study area. The high accretion of 178 ha was found nearby Pulicat Lake and low accretion of 19 ha was seen between Pulicat Lake and Kattupali Port. The high erosion area was found along the Pulicat Lake, Kattupali and Ennore ports, and Ennore creek mouth and southern Ennore such as Periya Kuppam, Chinna Kuppam, Kasi Koil Kuppam, and Thyagarajapuram. It may be concluded that the coastal erosion and accretion in the study area were mainly caused by anthropogenic and natural factors, which altered the coastal environment.

Global assessment of wind erosion based on a spatially distributed RWEQ model

Wind erosion is a global environmental problem and affects the sustainable use of land soil. The current efforts in wind erosion modeling mainly focus on local scales, yet very few studies have attempted to quantify the soil losses by wind on a large scale. Here, we proposed a distributed version of the revised wind erosion equation model (DRWEQ) to assess the spatial and temporal variations of wind erosion globally. The DRWEQ model used meteorological, soil, topographic, and remote sensing data to simulate global wind erosion from 2001 to 2010. The results showed that (a) the areas of wind erosion in Africa and Asia accounted for approximately 62% of the global wind erosion area but accounted for 91% of the global total soil loss; (b) global wind erosion showed a decreasing tendency during the research period – the wind erosion with a trend of intensification occupied 40.62% of the global wind erosion area while about 59.38% of the global wind erosion area showed a weakening trend; and (c) the monthly dynamics of the wind erosion were closely correlated with the combined effects of weather factors and vegetation coverage. The soil loss rates were lower in summer and reached the peak from January to April. The method presented in this study was developed based on the tradeoff of accuracy and availability of global data, and has the potential for predicting wind erosion from regional to global scales.

Erosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China

The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: λl = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW.

Gas–Solid Erosion Wear Characteristics of Elbow Pipe With Corrosion Defects

Corrosion and erosion are the main factors of pipes failure. Erosion wear characteristics of elbow pipe with corrosion defect are investigated in this paper. Initially, the erosion result of nondefect elbow pipe is calculated and compared to elbow pipe with corrosion defect. An elliptical erosion area with a V-shaped dent occurs at the extrados due to the particles' impact. The uniform corrosion defects change the structure of the pipe's inner surface. Therefore, the defect areas are more prone to be impacted by particles and then more severe erosion occurs. The maximum erosion rates of corrosion defect and noncorrosion area synchronously reach the maximum value as the corrosion defect located at 55 deg. The larger the particle mass flow rate is, the more severe the elbow pipe erosion is. As the flow rate increases, erosion rates of corrosion area and noncorrosion area increase, while the maximum erosion rate of corrosion area occurs at 55 deg. Structural parameters of corrosion defects affect the erosion. As the distance between two corrosion defects increases, the maximum erosion rate of lower corrosion defect increases. Considering the location, structure, and number of corrosion defect, a larger corrosion defect located in the middle of extrados has a worse effect on elbow pipe safety.

Average Quantifying the snowmelt dominant river erosion in Afghanistan between 2004-2020

<p>Flooding of rivers is one of the major causes of soil erosion leading to significant changes in the geomorphological environment. Particularly, in countries such as Afghanistan, where the transboundary are designated according to the Amu River shorelines, are significantly affected by riverbank erosions. Amu River is driven by streamflow from the Pir Pranjal ranges of Afghanistan and Tajikistan. Numerical analysis of the river flow dynamics in such regions is subject to the scarce data availability on ground stations. Thus, ERA5 Reanalysis data provides a significant means for the temporal analysis of the geomorphological changes in such multi-national watersheds.</p><p>In this study, we propose a framework to quantify the Amu riverbank erosion in the Kaldar District of the Balkh Province of Afghanistan. The proposed framework is based on establishing an empirical relationship between the riverbank erosion area based on the discharge intensity and the specific stream power. To determine these two parameters, the river discharge is modeled using the ERA5 Reanalysis hydrological parameters based on multivariate regression. The river width is determined using the Normalized Difference Water Index-based (NDWI) derived from the Landsat-7 and Landsat-8 datasets. The riverbank erosion area is determined using shoreline analysis carried out using these datasets. The shoreline analysis indicates that Afghanistan is losing precious land due to the riverbank erosion over the past two decades (2004-20) amounting to as much as 86 sq. km and on average 5.4 sq. km every year. According to the ERA5 Reanalysis data, the water contribution from snowmelt in the spring and the summer was significantly dominant compared to the precipitation, which is consistent with several other watersheds in the north-western Himalayas. The river width and the discharge are observed to follow a power-law relation with an r<sup>2 </sup>of 0.7. Additionally, the discharge intensity and the specific stream power showed significant relation (r<sup>2 </sup>of 0.84 both) corresponding to the riverbank erosion area, where the peak flood events were observed to be outliers.</p>

Coastal Stability using Remote Sensing and Radioactive Materials in the Northwest Nile Delta Coast, Egypt

This paper points to changes of the coastline using two ways, calculating the annual rate of erosion using 1) radioactive materials and 2) GIS and DSAS extension. Finally, both results were verified. Radioactivity results indicate both erosion and accretion zones, the annual scavenging rate in Promontory area shows that it is presented main accretion area, unlike the results of the DSAS extension, which showed that the Promontory is erosion area. The Burullus area annual scavenging rate results showing erosion, despite results of DSAS, it shows that it is an accretion area, but this was clarified by calculating the average distance between the shoreline of 2017 and 2018, and the 2018 shoreline retreat with an average distance 41.4 cm, which makes the Burullus region suffer from erosion. Two methods showed similarity in results in the Edco area, which shows that the Edco area suffers from erosion.