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A geospatial approach to flash flood hazard mapping in the city of Warangal, Telangana, India

Abstract

Dense urbanization leading to uncontrolled transformations within settlements result in flash flooding with overflowing drains leading to a greater inconvenience for the public and damage to private properties. Hence mapping of flash floods would be useful in identifying the high-risk flood zones for disaster response and urban services, during emergencies with rainfall events of high intensity. This article aims to prepare a flood hazard map of Warangal Municipal Corporation (WMC) in Telangana State, India. WMC is chronically affected due to a rise in water levels resulting in flash floods, with an increase in encroachments. The factors considered in this study are rainfall (curve number), surface slope and surface roughness, type of soil, and distance to main channel, drainage density, and land use cover. To decide the relative weight of the impact of each flood causative factors an Analytical Hierarchical Process (AHP) was used. Accordingly, a composite Flood Hazard Index (FHI) has been derived by using the multiple-criteria decision-making tools by integrating these into a Geographical Information System (GIS). The Soil and Water Assessment Tool (SWAT) in Quantum GIS (QGIS), which is a hydrological model, was used to evaluate the projection of streamflow over the water basin and model parameters were optimized using water balance equations during calibration and validation periods.

Open access
The impact of tourism on local communities and their environment in Gilgit Baltistan, Pakistan: a local community perspective

Abstract

The northern area of Pakistan, Gilgit Baltistan (GB), has huge tourist potential due to its exotic mountain beauty. According to the GB Tourism Department, a large number of tourists (around 200651) visit GB every year from across the country. Due to a large influx of tourists in the area both positive and negative impacts have been felt especially on the environment and on the local communities. The environmental impacts of tourism were investigated in this research in two districts of GB. Three villages were selected from each of the districts of Hunza and Diamer as the basis of this research. This study was based on the perceptions and attitudes of the respondents. The total number of questionnaires completed was 340 filled from different respondent categories. Results showed that deforestation, loss of biodiversity, generation of solid waste, water, air and noise pollution, damage cultural and heritage sites and are the main environmental issues caused by tourism activities in the villages in these districts. About 42% of respondents said that deforestation and loss of biodiversity were high in the Diamer district while in Hunza 39% of respondents said that solid waste generation was high. Similarly, 21% respondents in Hunza and 14% respondents in Diamer agreed that water pollution is caused by tourism activities. Microbial analysis of water confirmed the presence of Salmonella typhi, E. coli and Enterobacter sp. There were positive impacts of tourism with results revealing that 87% of villagers and 98% of businessmen responded that tourism had provided them with jobs and business during the peak tourism season. Hotels and restaurants are the main source of jobs in GB mainly as porters and guides. According to the data collected dry fruits, medicinal herbs, gemstones and handicrafts provided considerable attractions for tourists. It is recommended that a combined effort be made by the local communities, tourism departments and other Govt. Agencies to ensure the cleanliness of tourist attractions.

Open access
Influence of discharged industrial effluents on the parameters of surface water in Onitsha urban area, southeastern Nigeria

Abstract

Chemical industries in Onitsha urban area of southeastern Nigeria have been discharging large quantities of effluents into surface streams. These streams are the primary sources of water used by poor households for domestic purposes. This study examines the effects of effluents on the physicochemical and microbiological characteristics of the recipient streams. This objective was achieved by collecting eight effluents and twenty-two water samples from control points, discharge locations and exit chutes of the effluents for analysis. The results of the study characterised the effluents and their effects on the recipient streams. The effluents cause gross pollution of the streams as most of the parameters including pH, total dissolved solids (TDS), turbidity, biological oxygen demand (BOD), chemical oxygen demand (COD), Mg, NO3, Fe, Cu, Pb, Cr, total heterotrophic count (THC) and total coliform group (TCG) returned high values that exceeded the World Health Organisation’s (WHO) benchmark from 2011 for drinking water quality. Only dissolved oxygen (DO), Na, Zn, Ca, and Na returned values lower than the WHO guideline. E. coli was found in all the samples; TCG was also high. This paper, therefore, recommends that the effluent generating industries should treat their effluents before disposal.

Open access
Interpretation of the results of monitoring of the piezometric measurements of the Chańcza dam in 2014–2017

Abstract

The occurrence of a hydraulic connection between piezometers is identified based on similar changes in water levels. Some piezometers react to changing upper or lower water levels, some may also react to atmospheric precipitation. If the reaction to variable upper water levels is significant, then leakage of seepage control devices is identified and the dam is subjected to repair works. The aim of this research paper is to present and analyse the dynamics of variability of water levels in open piezometers of the Chańcza dam, located at the 36 km of the Czarna Staszowska River in the town of Korytnica in Świętokrzyskie province (Poland). Before the analysis of the piezometric data was commenced, the Grubbs statistical test was used to identify and reject the outliers. The scope of the research includes the data captured between January 14, 2014 and January 13, 2017. A hypothesis was formulated that the change in the trend occurred after the spring of 2015 when the water level in the reservoir was reduced by approx. 1.5 m. Two trend lines were adapted for the water levels of each piezometer using the least squares method – the first one for the period from January 2014 to May 2015, and the second one from June 2015 to January 2017. In this way, two slopes of the linear function were obtained together with an estimation of their errors. These slopes were compared using a statistical parallelism test.

Open access
Introduction to Coastal HF Maritime Surveillance Radars

Abstract

This paper presents the main technical characteristics and working performances of coastal maritime surveillance radars, such as low-power High-Frequency Surface Wave Radars (HFSWR) and Over the Horizon Radars (OTHR). These radars have demonstrated to be a cost-effective long-range early-warning sensor for ship detection and tracking in coastal waters, sea channels and passages. In this work, multi-target tracking and data fusion techniques are applied to live-recorded data from a network of oceanographic HFSWR stations installed in Jindalee Operational Radar Network (JORN), Wellen Radar (WERA) in Ligurian Sea (Mediterranean Sea), CODAR Ocean Sebsorsin and in the German Bight (North Sea). The coastal Imaging Sciences Research (ISR) HFSWR system, Multi-static ISR HF Radar, Ship Classification using Multi-Frequency HF Radar, Coastal HF radar surveillance of pirate boats and Different projects of coastal HF radars for vessels detecting are described.

Ship reports from the Automatic Identification System (AIS), recorded from both coastal and satellite Land Earth Stations (LES) are exploited as ground truth information and a methodology is applied to classify the fused tracks and to estimate system performances. Experimental results for all above solutions are presented and discussed, together with an outline for future integration and infrastructures.

Open access
Lyapunov Function based Criteria for Ship Rolling in Random Beam Seas

Abstract

The aim of this study is to present a Lyapunov function which can be used to derive an intact stability criterion for a ship in random beam seas. First, the mathematical model of the rolling motion of ships in random beam seas is introduced. The random wave excitation is described by a spectrum which is depended on the wave energy spectrum and the amplitude of the moment of roll. This spectrum is generated by a second order linear filter. Second, the methodology of creating a Lyapunov function is explained briefly. Then, there is outlined the way by which Lyapunov function can be used as the intact stability criterion for a ship. The proposed criterion is derived by considering the weather criteria for German naval vessels. Finally, the coherence of the boundary of safe basin obtained by Lyapunov function with the numerical results obtained by Euler-Maruyama Method is presented. From the results it can be deduced that the Lyapunov function can be used to define an intact stability criterion.

Open access
Management of hazard of flooding in arid region urban agglomeration using HEC-RAS and GIS software: The case of the Bechar's city

Abstract

During the last few years, the City of Bechar in Algeria has witnessed some extreme events, such as the great flood of the year 2008 in which an exceptional amount of rain was recorded with a flow rate of 830 m3∙s−1 (h water = 4 m, b = 200 m); similar flooding also occurred in 2012 and 2014. The problem is that most of the City of Bechar has an urban sprawl that extends to the banks of Wadi Bechar, which represents a huge risk for the lives of the inhabitants of the region. The present work aims to assess the flood risk through flood hazard mapping. This method consists in determining the flow rates for the return periods of 25 years (Q 25 = 388.6 m3∙s−1, h water = 3.5 m, b = 200 m, S spot = 55.35 ha), 50 years (Q 50 = 478.3 m3∙s−1, h water = 5 m, b = 200 m, S spot = 66.48 ha) and 100 years (Q 100 = 567.3 m3∙s−1, h water = 7 m, b = 200 m, S spot = 133 ha). For this, it is necessary to adjust the flow rates using Gumbel law along with some computer supports such as HEC-RAS, HEC-GeoRAS and ArcGis for mapping the event. Finally, this work enables us to determine the zones exposed to risk of flooding and to classify them according to the flood water height.

Open access
Model Predictive Super-Twisting Sliding Mode Control for an Autonomous Surface Vehicle

Abstract

This paper presents a new robust Model Predictive Control (MPC) algorithm for trajectory tracking of an Autonomous Surface Vehicle (ASV) in presence of the time-varying external disturbances including winds, waves and ocean currents as well as dynamical uncertainties. For fulfilling the robustness property, a sliding mode control-based procedure for designing of MPC and a super-twisting term are adopted. The MPC algorithm has been known as an effective approach for the implementation simplicity and its fast dynamic response. The proposed hybrid controller has been implemented in MATLAB / Simulink environment. The results for the combined Model Predictive Super-Twisting Sliding Mode Control (MP-STSMC) algorithm have shown that it significantly outperforms conventional MPC algorithm in terms of the transient response, robustness and steady state response and presents an effective chattering attenuation in comparison with the Super-Twisting Sliding Mode Control (STSMC) algorithm.

Open access
A more efficient valuation of beaches using tourists’ perspectives and Geographic Information System (GIS): The case of Patenga of Chittagong, Bangladesh

Abstract

The valuation of non–marketed goods and services of beaches in developing nations is rarely conducted; thus, lax management efforts at these resource–rich places often lead to degradation. In an attempt to resolve this issue the research used the travel cost valuation method and incorporated the use of geographic information system to estimate a never-before-done non-market valuation of the area visited by respondents at the beach of Patenga of Chittagong, Bangladesh. The uniqueness of the research stems from defining the area enjoyed by the survey respondents, via mapping, which helped assign the value generated to that particular part of Patenga and not the rest; this significantly decreased the underestimation problem of the travel cost methodology. The research used secondary sources and collected responses and geographical data from surveys conducted over a seven day period in March of 2018, from 277 respondents. A value of at least 14,331,044BDT/USD1.71million was estimated for 2018 for only 9% of Patenga. Furthermore, the Willingness to Pay approach was used to propose an entry fee of 15BDT/USD0.18 which would yield a revenue of more than 6,750,000BDT/USD79,882 around the year. The authors believe, these results will push the policy-makers and encourage stakeholder participation to better implement and monitor environmental management measures at Patenga.

Open access
Multi-phase flow assessment for the fermentation process in mono-substrate reactor with skeleton bed

Abstract

The selected techniques were reviewed and their technological aspects were characterized in the context of multi-phase flow for biogas production. The conditions of anaerobic fermentation for pig slurry in a mono-substrate reactor with skeleton bed were analysed. The required technical and technological criteria for producing raw biogas were indicated.

Design and construction of the mono-substrate model, biogas flow reactor, developed for cooperation with livestock buildings of various sizes and power from 2.5 kW to 40 kW. The installation has the form of a sealed fermentation tank filled with a skeletal deposit constituting a peculiar spatial system with regular shapes and a rough surface.

Incorporating a plant in such a production cycle that enables the entire slurry stream to be directed from the cowshed or pig house underrun channels to the reactor operating in the flow mode, where anaerobic digestion will take place, allows to obtain a biogas.

The paper presents preliminary results of experimental investigations in the field of hydrodynamic substrate mixing system for biogas flow assessment by the adhesive bed in the context of biogas production. The aim of the study was to assessment and shows the influence of the Reynolds number on the biogas resistance factor for the fermentation process in mono-substrate reactor with adhesive deposit. The measurement results indicate a clear effect of the Reynolds number in relation to the descending flow resistance coefficient for the adhesive bed.

Open access