Stream flow trends in up and midstream of Kirindi Oya river basin in Sri Lanka and its linkages to rainfall

Trend analysis of hydro-climatic variables provide useful information for effective planning, designing and management of water resources and agricultural production. Trends in observed stream flow at upstream and midstream gauging stations (GS), Wellawaya, Thanamalwila & rainfall and temperature in the Kirindi Oya river basin were assessed using the Mann-Kendall, Modified Mann-Kendall and Sen’s slope. Average rainfalls for the two catchments and for the entire basin were computed using ‘Thessen polygon’ method. The relationships between trends in stream flow and catchment rainfall were studied by Spearman’s Rho correlation coefficient . Five year Moving averaged Standardize Anomalies (FMSA) of both annual stream flow and rainfall at Wellawaya and Thanamalwila catchments were in a non-significant (p < 0.05) decreasing trend for 1994 to 2010.Though there was a positive correlation between annual catchment rainfall and stream flow of these two catchments, correlation was significant (p < 0.05) only at Thanamalwila (0.69) suggesting that the variation of annual stream flow at Thanamalwila GS was mainly attributed to the variation of catchment rainfall. However, variation of stream flow during North East Monsoon (NEM) season was mainly attributed to the variation of respective catchment rainfall of both the catchments as evident by significant higher ‘p’ at Wellawaya (0.61) and Thanamalwila (0.69). This study also found that trend of FMSA of South West Monsoon (SWM) rain was significantly (p < 0.05) decreasing for the entire basin, Thanamalwila and Wellawaya sub-catchments. Stream flow at Wellawaya GS during SWM was also found to be significantly decreasing while Thanamalwila stream flow was non-significantly decreasing. Both rainfall and stream flow during First Inter Monsoon (FIM) was in a significant increasing trend particularly in the month of April. These observed trends during SWM and FIM suggest an apparent early onset of SWM in the basin, or drastic deviation in receiving rain during SWM in the Kirindi Oya river basin.

Influence of Level of Detail (LOD) in Hydraulic Model Geometry with Demand Allocation by Voronoi Polygon Method on Chosen Parameters

Deciding on the level of model complexity is one of the first decisions that has to be made before engaging in the creation of a functional hydraulic model of a municipal water supply system. There are a number of influencing factors such as time needed to simulate the network, time needed to create such model and ease of use. The aim of this work is to prove that level of detail has influence on parameters such as pressure at measurement points, spread of flow speed and flow volume at different parts of mains. The Voronoi polygon method is one of the basic demand allocation methods, which, in the event of a different number of junctions depending on model complexity, has to generate a varying number of polygons of different sizes used to aggregate the demands.

Characteristics of Landslide and Rainfall Areas in Majalengka Regency, West Java Province

Majalengka Regency is one of the districts with a high landslide hazard in West Java Province. They are mostly affected by heavy rainfall or prolonged rain. This study aims to classify landslide events in 2018-2019 based on physical factors consisting of slopes, soil types, lithology, land use, and vegetation density using the K-Means Clustering analysis method. To analyze the characteristics of rainfall that triggered landslides in 2018-2019 using the Thiessen polygon method. The results showed that the clustering of landslide events in 2018-2019 in Majalengka Regency was formed five clusters with the highest rainfall on the D-Day average in cluster 5, which is 49 mm/day. The highest average cumulative rainfall 3 days before the landslide events was in cluster 4, which is 80 mm/day. The highest average cumulative rainfall 5 days before the landslide events was in cluster 3 is 112 mm/day. The highest average cumulative rainfall 10 days before the landslide events was in cluster 1, which is 174 mm/day.

The Natural Disaster Prone Index Map Model in Indonesia Using the Thiessen Polygon Method

Natural Disasters are natural phenomena that occur at any moment that can cause loss. Indonesia is an archipelagic country located at the meeting of four tectonic plates and volcanic belts. This condition causes Indonesia to be prone to natural disasters. Therefore, it is necessary to make a natural disaster-prone index map model minimize the impact of natural disasters. In this research, the researchers used a Polygon Thiessen method for it was one of the mapping methods to determine a natural disaster based on Indonesia's vast surface and many disasters. The BNPB and Polygon Thiessen data comparison shows that BNPB data has a low level of vulnerability of 302, a moderate level of vulnerability of 148, and a high level of vulnerability of 58. In contrast, the Thiessen polygon has a low level of vulnerability of 297, a moderate vulnerability of 158, and a high vulnerability of 59. Comparing BNPB data and the Thiessen Polygon method found five differences from 40 data in the Papua region. Suggestions for further research to create an application-based information system so that it can be accessed in real-time.

Geometrical- and Tooth Contact Analysis of the Areas and Perimeters on the Archimedean Worm Wheels Depending on the Modification of the Axial Module

With the knowledge of the recommendations from reference literatures - six types of Archimedean worm gear drives were designed with the modification of the axial module. After that computer aided models were generated. These pairs were loaded by the same torque to analyse the mechanical parameters on the tooth contact zone. Due to the geometrical establishment, three teeth are connected with the worm surface at the same time, that is why these teeth are analysed. Polygon method was used to approach the kinematical impression on the worm wheel surface. As a result, we were able to define the area- and perimeter percentages of these impressions on the worm wheel surface for each tooth. We also determined the correlation between the axial module and the analysed mechanical parameters supposing average values on the contact surfaces.

In Situ Stress Prediction in Subsurface Rocks: An Overview and a New Method

Methods for determining in situ stresses are reviewed, and a new approach is proposed for a better prediction of the in situ stresses. For theoretically calculating horizontal stresses, horizontal strains are needed; however, these strains are very difficult to be obtained. Alternative methods are presented in this paper to allow an easier way for determining horizontal stresses. The uniaxial strain method is oversimplified for the minimum horizontal stress determination; however, it is the lower bound minimum horizontal stress. Based on this concept, a modified stress polygon method is proposed to obtain the minimum and maximum horizontal stresses. This new stress polygon is easier to implement and is more accurate to determine in situ stresses by narrowing the area of the conventional stress polygon when drilling-induced tensile fracture and wellbore breakout data are available. Using the generalized Hooke’s law and coupling pore pressure and in situ stresses, a new method for estimating the maximum horizontal stress is proposed. Combined it to the stress polygon method, a reliable in situ stress estimation can be obtained. The field measurement method, such as minifrac test, is also analyzed in different stress regimes to determine horizontal stress magnitudes and calibrate the proposed theoretical method. The proposed workflow combined theoretical methods to field measurements provides an integrated approach for horizontal stress estimation.

Variação das dunas no Balneário Barra do Chuí, extremo sul do Brasil, entre 2005-2018

As dunas costeiras são feições naturais formadas a partir das praias arenosas, devido a interação do vento, areia e vegetação. No entanto, a ação humana torna-se uma variável cada vez mais relevante em sua dinâmica, ocasionando problemas ambientais. O presente trabalho tem como objetivo quantificar e caracterizar, a partir de uma série temporal de imagens orbitais no intervalo entre 2005 e 2018, a mobilidade das dunas no Balneário Barra do Chuí – RS, especificamente a variação na base das dunas frontais. O intuito é verificar processos de erosão e sedimentação na orla do balneário, bem como a variação do limite do reverso do campo de dunas, onde se encontra a área urbana edificada do balneário. A metodologia foi empregada a partir de imagens orbitais adquiridas no software Google Earth Pro® e técnicas realizadas nos softwares ArcGIS 10.3.1® e ERDAS Imagine 2013®. A variação das linhas de costa analisadas foi obtida a partir do Método do Polígono de Mudança, por meio de uma linha de controle aplicada aos limites praia-duna frontal e reverso da duna. O Balneário Barra do Chuí, no período estudado, apresentou predomínio de taxas de erosão das dunas frontais, onde depósitos pleistocênicos estão sendo diretamente trabalhados pela ação marinha. O reverso das dunas apresentou tendência de avanço em relação à retroterra. Constatou-se que em alguns locais o transporte eólico de sedimentos está soterrando algumas residências. Palavras-chave: Limite praia-duna. Reverso das Dunas. Geotecnologias. Método do Polígono de Mudança. Foredune variation in the Barra do Chui coastal settlement, southern Brazil, between 2005-2018ABSTRACT Foredunes are natural features formed from sandy beaches, due to the interaction of wind, sand, and vegetation. However, human action becomes an increasingly relevant variable in its dynamics, causing environmental problems. The present work aims to quantify and characterize, from a time series of orbital images in the interval between 2005 and 2018, the dune mobility in the Barra do Chui coastal settlement, specifically the variation in the base of the frontal dunes, in order to check erosion and sedimentation at the edge of the resort, as well as the variation of the limit of the reverse of the dune field, where the built-up area of the resort is located. The methodology was used based on orbital images acquired in the Google Earth Pro® software and techniques performed in the ArcGIS 10.3.1® and ERDAS Imagine 2013® software. The variation of the coastlines analyzed was obtained from the Change Polygon Method, through a control line applied to the frontal and reverse dune beach-dune limits. The Barra do Chui coastal settlement, in the studied period, presented a predominance of erosion rates of the frontal dunes, where Pleistocene deposits are being directly worked by the marine action. The reverse side of the dunes showed an upward trend in relation to the retrograde, in fact, in some places, wind sediment transport has already been burying some homes. Keywords: Dune-Beach Limit. Dunes Reverse. Geotechnologies. Change Polygon Method

Spatially Variable Precipitation and Its Influence on Water Balance in a Headwater Alpine Basin, Nepal

The current knowledge of the spatial variability of precipitation in High Mountain Asia is based on the remotely-sensed estimates (coarse spatial and temporal resolution) or data from sparsely-distributed rain gauges. However, as precipitation is strongly affected by topography in mountainous terrain, the spatially varying precipitation and the resulting water balances are currently poorly understood. To fill this gap in knowledge, we studied the spatial variation of the precipitation and its impact on water balance in a small headwater basin located in the foothills of the Himalaya, Nepal. We deployed ten rain gauges and climate stations, spanning the whole elevation range 700–4500 m above sea level (masl) for a period of four years. Our results show a quadratic polynomial relationship between annual precipitation and station elevation, which are used to produce annual precipitation maps. The performance of the elevation-based precipitation estimates is adequate in closing the water balance while the performances of average precipitation and Thiessen polygon method are poor and inconsistent in closing the water balance. We also demonstrate that precipitation estimates from one or two gauges at the lowest basin elevation substantially underestimate the water balance. However, the precipitation from one or two rain gauges at 2000–3000 masl provide a significantly better estimate of the water balance of a small headwater basin.

Application of the polygon method to analyze the differentiation of the regions of the Volga federal district by the level of e-business development

The materials of the article contain an integral assessment of the level of development of e-business on the example of the regions of the Volga Federal District (VFD). As a result of calculating the private and local ranks of the values of the selected criteria, fourteen polygons of the level of e-business development were built by the number of regions in the district. The results obtained make it possible to ascertain the existence of a high degree of heterogeneity of the VFD regions in terms of the level of e-business development. The leading regions include the Republic of Tatarstan, the Perm Territory, and the Nizhny Novgorod Region. The outsider regions - the Republic of Mari El, the Republic of Mordovia and the Kirov region - are characterized by a low share of organizations that used the capabilities of the Intranet and Extranet in their activities, the lack of special software tools for managing sales of goods (works, services), limited use of software, in particular, ERP-, CRM and SCM-systems.