Lab-scale investigation on Bar formation coordinates in river based on flow and sediment

Mat Salleh M. Z., Ariffin J., Mohd-Noor M. F. and Yusof N. A. U.

The study presents the first detailed experiment based analysis on the formation of mid channel bar in river. The continuous development on erosion and sedimentation leads to the formation of mid-channel bars. The bar formation occur at the inner bank of river. It was actively occurring at downstream and not visible at upstream. The most factor that leads to the bar formation was the flow of water. The present of sediment in river induced the formation of bars but not active as compared to the effect of flow. Thus, this study centers towards the behavior of bar formation coordinates with flow and sediment.

Geopolymerization of metakaolin using rice husk ash as silica source with NA based activator

Sazmal E. Arshad, Selva M. Aripitri and Ellyza S. M. Zainuddin

A study on alternative to Portland cement was carried out by applying geopolymerization process using metakaolin (MK) and rice husk ash (RHA). Metakaolin was produced through the calcinations of kaolin-processed clay at 700oC. Acid leachedraw rice husk (RH) was incinerated at 700oCto produce rice husk ash (RHA), which acted as the silica source in the synthesis of geopolymer. Geopolymers (GP1-GP6) were produced by the alkaline activation (NaOH and Na2SiO3) of mixtures of metakaolin (MK) and rice husk ash (RHA) before curing them at 60oC. The parameters involved were Na2SiO3/NaOH ratio and metakaolin/silica ratio. The effects of SiO2/Al2O3 ratio and solid/liquid ratio on the workability, brittleness, porosity and setting time of geopolymers were studied. The hardened geopolymer materials were sintered at temperature ranged from 600 to 1,000oC. Observations showed that the workability decreased when the alkali activator was doubled up, brittleness increased by increasing the SiO2/Al2O3 ratio and at high solid/liquid ratio, the porosity decreased and eventually producing material that was less brittle. The optimum SiO2/Al2O3 ratio was 3.18. Scanning Electron Microscope (SEM) micrographs and X-ray Diffraction (XRD) analysis showed the development of the geopolymer materials in the phase evolution in increasing temperature. At the highest temperature of sintering for GP1 (1, 000oC), nepheline crystals were the main crystals formed with mullite as the minor crystals which started to develop. The presence of the crystalline phases can be further related to the mechanical strength of the geopolymer.

Spatiotemporal variations of the hydrodynamic parameters of Ndjili river to Djambala

Mbilou Urbain Gampio, Masdingam Aristide, Mabondzo-Ngouala Medard and Nganga Dominique

The essential goal of this study is to provide information on the variation of the hydrodynamic parameters of the river N’djili which constitutes a source of supply raw water at the company in head of water in the town of Djambala, in order to make it possible to the public and private decision makers not only to become aware on the impacts which these variations with long can pose but also to take measures for the improvement of drinking water production in Djambala, considering its population believes exponentially; then, for the durable management of this river N’djili which is seen threatened of drying up.We noted that the flow and the depth of the N’djili River are proportional to pluviometry. Moreover varies with its depth.This river is the source provisioning of raw water of the National Company of Distribution of water (SNDE).This study made it possible to note some variations of the hydrodynamic parameters of this river which is seen threatening of disappearance by the climatic changes.While appearing with others rivers tekes which made object former studies of the researchers like Olivry J.C (1967), one notices that the depth of the N’djili River is very low.

Identification of failure surfacesin dragline dumps of opencast coal mines

S. Sharma, S. Sengupta and I. Roy

Overburden dumps are an integral part of open pit coal mining. With an increase in the mining activity to meet the energy demands, the volume of overburden dumps in the open pit mines is also increasing. Draglines being the most versatile excavating machines are the favourable and most used machinery for dumping of the overburden material. Inadequacy of dumping space within the pit leads to the formation of steep and high dragline dumps which then succumbs to various failure modes following certain failure paths. This paper identifies the most probable failure paths with least factor of safety, within the overburden dragline dump masses of coal mines of Northern Coalfields Limited, Singrauli, India. This paper also identifies the different failure pattern and modes within the overburden dragline dump masses along the derived failure path.

A study of rainwater harvesting practice in semi-arid areas in the Dodoma region, Tanzania: Planning phase

Ombeni John Mdee

Basins offer potential source points to collect runoff water during rainfall, especially in areas that are associated with highly variable rainfall and long dry periods. The Dodoma region is surrounded by hills and valleys, which offers an efficient and reliable water harvesting opportunity. This study identifies seven (7) potential basins with seventy-nine (79) pour points for sub-basin development by using topography and river network maps created from the ArcGIS software application. Each of the basin’s features were analysed based on the drainage area, which included the minimum, mean and maximum elevations, and soil type. However, when rainfall was analysed, it indicated a break during the rainy season that resulted in a long dry period. This study uses Google Earth to validate identified pour points and results indicated the possibility of conducting site visits for further implementation of the sub-basins. Therefore, the study presents the possibility of harvesting rainwater in semi-arid areas, which could be used for agriculture activities and by local communities around the basin.

Morphometric analysis of the Sumanpa river catchmentat Mampong-Ashanti in Ghana

Kotei R., Agyare W. A., Kyei-Baffour N. and Atakora E. T.

The study determined and analysed morphometric characteristics of the Sumanpa catchment in the Forest-Savannah Transitional zone of the Ashanti Region of Ghana. Quantitative morphometric parameters were determined using remote sensing and GIS techniques to assess the requirements for ecological and hydrological conservation, planning, development and management of the catchment landscape. Results indicated that the total length of stream segments was highest under the first order streams and decreased as the stream order increased. The catchment has an area of 38 km2with channel closeness of 0.934 km km-2 indicating permeable sub-soil. The catchment has a relief of 137m and a total length of stream network of 36.51km out of which 61% was ephemeral, 38.9 % was second and third order streams. The catchment has 44 % of its area located on slopes between 5-10o with generally good vegetation cover. There are 31 streams linked to a 3rd order trunk stream forming a trellis drainage pattern. The catchment’s morphometric features suggest a general fragile topographic condition which needs strategic approach for soil and water conservation measures and urban landuse planning.

Hydro-Statistical analysis of flood flows with particular reference to Tilpara barrage of Mayurakshi river, Eastern India

Krishna Gopal Ghosh and Sutapa Mukhopadhyay

Flood is a common incidence in Mayurakshi River basin of Eastern India. However, in recent decades it has became quite irregular and its frequency has increased significantly. In the present article flood trend and frequency of lower Mayurakshi River Basin in relation to Tilpara Barrage has been focused and flood frequency has been analysed in terms of Log-Pearson Type III (LP3) distribution model. For this analysis annual peak discharge data at Tilpara gauge station and rainfall data of district head quarter Suri has been incorporated for the period 1954 to 2013. The results showed that, the distribution of flood flows was highly variable in the in the catchment (Cv = 0.984). Rainfall above a critical range is the leading factor to control barrage discharge and thereby to cause flood. The estimated threshold rainfall is 550 mm. and threshold discharge of 180000 cusec to cause flood. Estimated mean daily discharge available for the barrage is 2602.74 cusec but actual average barrage discharge for the period is 1175.169305 cusec. The extra inflow amount is regularly diverted to other river system through irrigation canal. The estimated discharges as per LP3 for the return period of 2, 5, 10, 25, 50, 100 and 200 years are 19241.35, 59202.45, 109328.29, 214359.44, 334201.82, 502387.10, 733880.19 cusec, respectively. The equation which relates the expected discharge(y) to return period is given y = 14990ln(x) - 18160. These values are useful for hydraulic design of structures in the catchment area and for storm water management.

Land evaluation as a basis for agriculture crops development case in Raumoco Lautem Timor Leste

Antonio Joao da Costa, Bambang Hendro Sunarminto, Totok Gunawan and Sri Nuryani Hidayah Utami

Land evaluation is the process of assessing the potential of land or land for predicting the performance of a particular use. Land use for agriculture crops in particularly annual crops needed information from land quality and characteristics and it obtained through land evaluation. Soil fertility and land suitability evaluation is the way to get this information. The aims of this research are to assess the quality and characteristics of the land, potential and constraints of soil fertility and land suitability for rice and pulses. Crops requirements in this purpose of the research obtained through the land survey system with land units. Land surveying activities have been conduct in Raumoco covering Lautem and Luro sub-districts of Lautem, Timor Leste from October 2013 to January 2015. Land area of 4603.8 ha consists of 136 units of land maps (SPL) and 11 land units (SPT). Each SPT is representing by one soil profile. Soil samples from pewakil profile and composites were analysis using a set of tools and chemicals soil analysis laboratory at Soil Department of Faculty of Agriculture, UGM Soil tipe in Raumoco (Lautem and Luro sub-districts) based on Kys to Soil Taxonomy (SSS, 2010) including Haplustalf (492.6 ha), Ustipsament (512.3 ha), Ustifluvent (230.1 ha), Calsiustoll (645.4 ha), Haplustept (1861.8 ha) and Haplustoll (861.7 ha). Those soils type formed under rainfall of 1044.7 mm year-1 with an average temperature ranges from 22.1 to 30.9oC with isothermic of soil temperature and ustic soil moisture regime. Soil and climate aspects as well as other physical factors (slope, rocks, erosion and flooding) used as a basis for this research. Research results of soil fertility evaluation by FCC system show that Lautem and Luro sub-district including low to high. Land which classified as low soil fertility is 995.7 ha (21.6%), medium = 1746.4 ha (37.9 %) and high = 1861.8 ha (40.5 %). The main obstacle of soil fertility is soil moisture droughts; whreas, land suitability evaluation by system contained 72.5 % is suitable for rice and pulses and 27.5 % not suitable both actual and potential condition. In addition, LPT Bogor system shows that the percentage of actual land of 16.1 % is suitable and 83.9 % not suitable. After the land improvement contained 25.3 % suitable (S) and 74.7 % not suitable (N) for rice (upland rice) and pulses (corn, soybean and peanut). This entire plant can developed in Lautem and Luro by considering water available, growing season and cropping pattern.

Quantification of soil erosion by water using GIS and remote sensing techniques: A study of Pandavapura Taluk, Mandya District, Karnataka, India

M. Vinay, Ramu and B. Mahalingam

Soil erosion is one of the major environmental degradation, which is caused by natural process like rainfall, high wind forces and also anthropogenic activities with improper utilization of lands with respect to agricultural activities, developmental activities and leading to severe erosion. The present study is conducted to quantify the soil erosion by water force. The revised universal soil loss equation methodology was adopted and these equations were brought into Geographical Information System (GIS) environment. The average annual rainfall with 34years was used to find the rainfall erosive factor, the soil erodibility factor was found using the properties of soil that consists the percentage of clay, loam and silt. Then topographic slope and length were found using ASTER digital elevation model and crop factor were derived from remotely sensed Landsat images and practice factor were set to one due to no conservation practices in study area. The result were found that 267.19 Km2 are having no erosion, 88.80 Km2 are having low erosion with less than 50 ton/ha/year, 28.54 Km2 are having moderate erosion with 50-100 ton/ha/year of soil erosion, 35.03 Km2 are having severe erosion with 100- 150 ton/ha/year and 96.76 Km2 are having extreme erosion with more than 150 ton/ha/year. The suitable conservation method should be adopted.