scholarly journals Modelling of Batang Rejang for Extreme Events

2013 ◽  
Vol 4 (3) ◽  
pp. 1-5
Author(s):  
D.Y.S. Mah ◽  
N.C. Nam ◽  
F.J. Putuhena ◽  
P.L. Law

Flood is a natural hazard. It happens when the water in a river channel is beyond the capacity of the channel to carry while the overflowing water is called as floodwater. Flood causes damage to life and property when it strikes a vulnerable population in the affected area. There are several townships located along Batang Rejang such as Kapit, Song, Kanowit and Sibu. The main objective of this paper is to develop a river model to map the extreme events for Batang Rejang. The method used in is river modelling by using InfoWorks RS software. This method is simulating the Batang Rejang in order to view the behaviours of the river in response to conditions and effects of extreme events over a given period of time. Flood maps computed from InfoWorks RS are for flood extent analysis as it provides insights to the damage for different locations at different flows. The maps are also useful for related authorities or parties to locate human activities at the catchment area and to carry out emergency flood plans in the future.

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hendri Irwandi ◽  
Mohammad Syamsu Rosid ◽  
Terry Mart

AbstractThis research quantitatively and qualitatively analyzes the factors responsible for the water level variations in Lake Toba, North Sumatra Province, Indonesia. According to several studies carried out from 1993 to 2020, changes in the water level were associated with climate variability, climate change, and human activities. Furthermore, these studies stated that reduced rainfall during the rainy season due to the El Niño Southern Oscillation (ENSO) and the continuous increase in the maximum and average temperatures were some of the effects of climate change in the Lake Toba catchment area. Additionally, human interventions such as industrial activities, population growth, and damage to the surrounding environment of the Lake Toba watershed had significant impacts in terms of decreasing the water level. However, these studies were unable to determine the factor that had the most significant effect, although studies on other lakes worldwide have shown these factors are the main causes of fluctuations or decreases in water levels. A simulation study of Lake Toba's water balance showed the possibility of having a water surplus until the mid-twenty-first century. The input discharge was predicted to be greater than the output; therefore, Lake Toba could be optimized without affecting the future water level. However, the climate projections depicted a different situation, with scenarios predicting the possibility of extreme climate anomalies, demonstrating drier climatic conditions in the future. This review concludes that it is necessary to conduct an in-depth, comprehensive, and systematic study to identify the most dominant factor among the three that is causing the decrease in the Lake Toba water level and to describe the future projected water level.


2014 ◽  
Vol 962-965 ◽  
pp. 1509-1512
Author(s):  
Lin Liu ◽  
Pin Lv

There are various signs indicating that the Earth's natural environment is changing toward unfavorable direction for species, which is highly suspected to be connected with human activities. In the last century, people all over the world have realized the severity of environmental issues. In the long history, Chinese ancient had already development good rules and methods to reach balance between economic development and environment sustainability. This paper will discuss how environmental concepts forms and which methods could be applied in the future.


2018 ◽  
Author(s):  
Junxi Zhang ◽  
Yang Gao ◽  
Kun Luo ◽  
L. Ruby Leung ◽  
Yang Zhang ◽  
...  

Abstract. The Weather Research and Forecasting model with Chemistry (WRF/Chem) was used to study the effect of extreme weather events on ozone in US for historical (2001–2010) and future (2046–2055) periods under RCP8.5 scenario. During extreme weather events, including heat waves, atmospheric stagnation, and their compound events, ozone concentration is much higher compared to non-extreme events period. A striking enhancement of effect during compound events is revealed when heat wave and stagnation occur simultaneously and both high temperature and low wind speed promote the production of high ozone concentrations. In regions with high emissions, compound extreme events can shift the high-end tails of the probability density functions (PDFs) of ozone to even higher values to generate extreme ozone episodes. In regions with low emissions, extreme events can still increase high ozone frequency but the high-end tails of the PDFs are constrained by the low emissions. Despite large anthropogenic emission reduction projected for the future, compound events increase ozone more than the single events by 10 % to 13 %, comparable to the present, and high ozone episodes are not eliminated. Using the CMIP5 multi-model ensemble, the frequency of compound events is found to increase more dominantly compared to the increased frequency of single events in the future over the US, Europe, and China. High ozone episodes will likely continue in the future due to increases in both frequency and intensity of extreme events, despite reductions in anthropogenic emissions of its precursors. However, the latter could reduce or eliminate extreme ozone episodes, so improving projections of compound events and their impacts on extreme ozone may better constrain future projections of extreme ozone episodes that have detrimental effects on human health.


2013 ◽  
Vol 13 (12) ◽  
pp. 3145-3156 ◽  
Author(s):  
M. Velasco ◽  
P. A. Versini ◽  
A. Cabello ◽  
A. Barrera-Escoda

Abstract. Global change may imply important changes in the future occurrence and intensity of extreme events. Climate scenarios characterizing these plausible changes were previously obtained for the Llobregat River basin (NE Spain). This paper presents the implementation of these scenarios in the HBV (Hydrologiska Byråns Vattenbalansavdelning) hydrological model. Then, the expected changes in terms of flash flood occurrence and intensity are assessed for two different sub-basins: the Alt Llobregat and the Anoia (Llobregat River basin). The assessment of future flash floods has been done in terms of the intensity and occurrence of extreme events, using a peak over threshold (POT) analysis. For these two sub-basins, most of the simulated scenarios present an increase of the intensity of the peak discharge values. On the other hand, the future occurrence follows different trends in the two sub-basins: an increase is observed in Alt Llobregat but a decrease occurs in Anoia. Despite the uncertainties that appear in the whole process, the results obtained can shed some light on how future flash floods events may occur.


2011 ◽  
Vol 11 (9) ◽  
pp. 2463-2468 ◽  
Author(s):  
Y. Tramblay ◽  
L. Neppel ◽  
J. Carreau

Abstract. In Mediterranean regions, climate studies indicate for the future a possible increase in the extreme rainfall events occurrence and intensity. To evaluate the future changes in the extreme event distribution, there is a need to provide non-stationary models taking into account the non-stationarity of climate. In this study, several climatic covariates are tested in a non-stationary peaks-over-threshold modeling approach for heavy rainfall events in Southern France. Results indicate that the introduction of climatic covariates could improve the statistical modeling of extreme events. In the case study, the frequency of southern synoptic circulation patterns is found to improve the occurrence process of extreme events modeled via a Poisson distribution, whereas for the magnitude of the events, the air temperature and sea level pressure appear as valid covariates for the Generalized Pareto distribution scale parameter. Covariates describing the humidity fluxes at monthly and seasonal time scales also provide significant model improvements for the occurrence and the magnitude of heavy rainfall events. With such models including climatic covariates, it becomes possible to asses the risk of extreme events given certain climatic conditions at monthly or seasonal timescales. The future changes in the heavy rainfall distribution can also be evaluated using covariates computed by climate models.


2021 ◽  
Vol 9 ◽  
Author(s):  
Steven D. Culberson

Estuaries are places on the earth where rivers meet oceans. When rain and snowmelt drain off the land, the fresh water collects in streams and rivers and eventually makes its way to the ocean. At the same time, the ocean has tides that push salty water upstream into the rivers. This place, where rivers and oceans mix, is called an estuary. Estuaries contain many kinds of habitats that are home to plants and animals. Many people work and live in estuaries. In this article, I describe what makes estuaries interesting and important to plants, animals, and people. I also explain how these important areas are under threat from certain human activities.


Author(s):  
K. Nizamuddin

Town planning is a comprehensive task involving several stages that takes the city from actual state it is in to a desired state in the future through various measures taken by the concerned planning authorities. A city may be viewed as a system or a complex whole consisting of different component parts related or interacting with one another so as to form a unity. The component parts of the systenl consists of persistent human activities that have a tendency to occur or recur at specific locations that is, the activities occur within adopted spaces which include buildings, parks, water, bodies etc. The co~l~leclionasm ong these parts are communications which enable various activities to inter;ict so that necessary patterns of huinan behaviour can occur. These communications are recurrent and spatially clustered such as roads, railn~aysp, ipelines, cables etc. Implemelltation of the plan involves control of the various components of thissystenl so that the intended state as set out by the goals of the plan would depend on the existing state of the city. Therefore a thorough knowledge of the present state of the city is the first and an ilnportant step in any planning process.


1995 ◽  
Vol 19 (6) ◽  
pp. 340-342
Author(s):  
John M. Kellett

The shift of power from specialist services to the primary care teams has forced the former to examine the value of their hallowed traditions. In psychiatry, and geriatric medicine, the catchment area is a favoured restrictive practice, enabling demand to be regulated to suit the resources of each team. It is time to decide whether this is a practice to be defended and retained or whether, like many other restrictive practices, it is harmful to the consumer.


2018 ◽  
Vol 10 (9) ◽  
pp. 1387 ◽  
Author(s):  
Chengbiao Fu ◽  
Shu Gan ◽  
Xiping Yuan ◽  
Heigang Xiong ◽  
Anhong Tian

Traditional partial least squares regression (PLSR) and artificial neural networks (ANN) have been widely applied to estimate salt content from spectral reflectance in many different saline environments around the world. However, these methods entail a great amount of calculation, and their accuracy is low. To overcome these problems, a probability neural network (PNN) model based on particle swarm optimization was used in this study to build soil salt content models. Furthermore, there is a clear correlation between the level of human activities and the degree of salinization of an environment. This paper is the first to discuss this matter. Here, the performance of the PNN model to estimate soil salt content from reflectance data was investigated in areas non-affected (Area A) and affected (Area B) by human activities. The study area is located in Xingjinag, China. Different mathematical procedures, five wave band intervals, and two types of signal input sources were used for cross analysis. The coefficient of determination (R2), root mean square error (RMSE), and ratio of performance to deviation (RPD) index values were compared to verify the reliability of the model. Particle swarm optimization was used to adjust the optimal smoothing parameters of the PNN model and to avoid the long training processes required by the traditional ANN. The results show that the optimal wave band interval of the PNN is between 1000 nm and 1350 nm in Area A and between 400 nm and 700 nm in Area B. The reciprocal (1/R) transformation after Savitzky-Golay (SG) smoothing of the signal source is optimal for both areas. The RPD for both is greater than 30, which shows that the PNN model is applicable to areas with and without human activities and the prediction results are very good. The results indicated that the optimal wave band intervals for PNN modeling differed in areas affected and non-affected by human activities. The optimal interval of the artificial activities region falls in the visible light portion of the spectrum, and the optimized wave band region without human activities falls in the near-infrared short-wave portion of the spectrum.


2014 ◽  
Vol 6 (1) ◽  
pp. 38-55 ◽  
Author(s):  
Stephen Leslie Wearing ◽  
Paul A. Cunningham ◽  
Stephen Schweinsberg ◽  
Chantelle Jobberns

Australia has long tried to portray itself as an environmentally responsible state and has consistently been a strong supporter of Whale Watching as an alternative to the practice of commercial and ‘scientific’ whaling. This paper explores whale watching in an effort to determine the economic and social viability of it as a sustainable marine tourism activity —and whether in the future the whale and the tourist can coexist or will the latter as with previous human activities such as whaling yet again create a ‘tragedy of the commons’ and displace the former. As an ecotourism product, whale watching holds the potential for sustainable practice, one that is both ecological and profitable. Responsible whale watching is seen as a clean, green industry that simultaneously supports local economies and promotes whale education and conservation. The question is can it live up to these expectations?


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