volume-09-Issue 1 (2017)
Modelling Water Demand and Efficient Use in Mbagathi Sub-Catchment Using Weap
SWES, volume-09, Issue 1 (2017) , PP 49 - 57
Published: 03 Apr 2017
by J. Nyika, G.N. Karuku, and R. N. Onwonga from Department of Land Resource Management and Agricultural Technology, Faculty of Agriculture, University of Nairobi, P.O. Box 29053-00625, Nairobi, Kenya
Abstract: Water systems have complex component interactions necessitating development and evaluation of management amidst uncertainties of climate and constrained natural resources. Conceptual models such as WEAP when used are effective planning and management tools as they forecast future effects of resource use efficiency at sub-catchment level using existent hydrological and climate data thereby acting as corrective measure to poor resources management. This study aimed at using WEAP model to forecast demand and analyze scenarios on efficient water use in Mbagathi subcatchment. WEAP model schematic was set to develop current and reference scenarios. Parameters used to run WEAP model were a GIS map of the sub-catchment, climate data from Kenya Meteorological Department at Dagorretti Corner Station, hydrological and water demand data from WRMA databases. High population growth and prolonged drought were predicted to increase water demand while reuse though not practised, was found by the model to be the most effective approach to manage unmet demands as compared to reduced conveyance losses and increased reservoir capacity. The study concluded that water reuse through exploitation of wastewater could be a viable solution to Mbagathi sub-catchment's water problems. read more... read less...
Keywords: water problems, necessitating development, evaluation of management, climate and constrained natural resources
Modelling and Prediction of Gully Initiation in the University of Benin Using the Gultem Dynamic Model
SWES, volume-09, Issue 1 (2017) , PP 41 - 47
Published: 06 Mar 2017
by N. Kayode-Ojo, J. O. Ehiorobo, and N.M. Uzoukwu from Department of Civil and Mechanical Engineering, University of Benin, Edo State, Nigeria
Abstract: For a very long period of time there was environmental equilibrium between rainfall and soil erosion in the University of Benin until man's intervention caused a disruption in the equilibrium by the improper termination of the external drainage structures in the University of Benin, Benin City Nigeria. This led to the initiation of gully erosion which has caused the University a lot of environmental damages and if left unchecked, the effect will escalate and become very devastating and disastrous. The study was to evaluate and analyze the gully erosion problem that is developing in the western end of the University of Benin with a view to providing useful information for future planning, land conservation and control. Topographical Survey of the gully site were carried out using Differential Global Positioning System (GPS) Survey for controls and Total Station instrument for mapping of gully bed, gully walls and bank. This was to acquire morphological data of the gully site and generate geospatial data needed for monitoring the progressive growth of the gully. Using the generated 3D co-ordinates, spot heights, contour and Triangular Irregular Network models were generated in ARC-GIS environment. Soil samples were collected from the gully site for laboratory analysis and tests carried out included Specific gravity test, Particle size analysis, Compaction test and Shear Strength test in order to ascertain the overall contribution of the soils to the erosion problem. The data obtained from the surveys and investigations were inputed into the GULTEM Dynamic Erosion Model, for the evaluation of the rate of gully channel initiation. From the results the area affected by the gully erosion in this site is 11,100 m2. The geotechnical investigation carried out, revealed that the clay content of the soil in the area is only about 18%. This makes the soil highly susceptible to erosion as soils with less than 30% clay content are easily erodible. It also showed that the soil is finely graded, fairly cohesive and does not compact well. Information from the geospatial data of the gully site, revealed that the University of Benin Gully became steeper between the years 2005 to 2012 and thereafter the slope began to flatten out. The result of the model showed that the computed rate of gully channel initiation increases initially and then began to decrease steadily with the longitudinal distance of the gully for the period under study and also correlates well with the physical observation of the gully at various time interval monitored.. These models were validated using the data on gully morphology and dynamics from University of Benin Gully Erosion site. read more... read less...
Keywords: Environmental equilibrium, Gully erosion, Network models, GULTEM Dynamic Model.
The Performance Analysis of Effluent Treatment Plants (ETPs) of Different Industries in Chittagong City
SWES, volume-09, Issue 1 (2017) , PP 29 - 40
Published: 20 Feb 2017
by Ohidul Alam, Sarkar Imran Wahid, Mohammed Kamal Hossain, Milan Kumar Chakraborty from Institute of Forestry and Environmental Sciences (IFES), University of Chittagong, Chittagong – 4331, Bangladesh, School of Resources and Environmental Engineering, East China University of Science and Technology (ECUST), Shanghai 200237, P.R. China, Chemical Department, Water Supply and Sewerage Authority (WASA), Chittagong, Banglades
Abstract: The study was executed at Kalurghat industrial area to determine the efficiency of ETPs by testing different physicochemical parameters. Results revealed that only 3 out of 9 industries treated their effluents efficiently and discharged following the standards of DoE. The remaining industries viz. Alfa Textile treated their effluent but the values of pH (10.2), DO (3.6 mg/L), BOD (89 mg/L), COD (282 mg/L), TSS (221 mg/L), and EC (4003 μS/cm) exceeded the standards, and released untreated effluents directly into the environment. Smart Jeans didn’t maintain the standard of EC (1927 μS/cm), DO (3.2 mg/L), BOD (96 mg/L) and COD (216 mg/L). Asian Apparels EC (1973 μS/cm), DO (4 mg/L), BOD (79 mg/L), and COD (221 mg/L) weren’t up to the standards. Similarly, Mans Fashion EC (1243 μS/cm), DO (3.7 mg/L), TSS (180 mg/L), BOD (78 mg/L), and COD (255 mg/L) also exceeded the standards. In addition, Well Group TSS (160 mg/L), EC (3201 μS/cm), DO (4.2 mg/L), and COD (235 mg/L) while Golden Height only EC (1762 μS/cm) crossed the prescribed limits. Inversely, all the sampled industries volleyed effluents containing metals within the standards level except Alfa Textile (Cu, Zn, & Cr), Well Group (Cr) and Asian Apparels (Ni). read more... read less...
Keywords: Effluents, ETP, Efficiency, Environment, Industry, and Pollution.
Calibration and Validation Of Swat For Sub-Hourly Time Steps Using Swat-Cup
SWES, volume-09, Issue 1 (2017) , PP 21 - 27
Published: 20 Feb 2017
by Sa’d Shannak from Postdoctoral Researcher, Biological and Agricultural Engineering, Texas A&M AgriLife, Dallas, Texas
Abstract: SWAT is a semi-distributed, lumped parameter, continuous time model that simulates hydrology and water quality in watersheds. Traditionally, the model operated at a daily time step and it estimated the influence of landuse and management practices on water and agricultural chemical yields in a watershed. The daily time step format may not be sufficient to capture the impact of flashy storms where peak flows last for minutes only and are not reflected in daily average flows. A sub-hourly SWAT model for urban applications was developed but is not widely used. The main goal of this study was to present a basic methodology to calibrate sub-hourly SWAT models using SWAT-CUP. SWAT was tested using data from the Blunn Creek Watershed in Austin, Texas. The model was calibrated and evaluated using two separate representative 2-year periods bracketing hydrologic conditions experienced in the watershed. Results show that the sub-hourly SWAT provides reasonable estimates of stream flow for multiple storm events. read more... read less...
Keywords: Sub-hourly, SWAT, SWAT-CUP, SUFI-2, Uncertainty, Hydrological Modelling
The Effects of Cloud Model Initialization on Sulfate Chemistry Transport and Wet Deposition over Macedonia
SWES, volume-09, Issue 1 (2017) , PP 09 - 20
Published: 06 Feb 2017
by Vlado Spiridonov, and Mladjen Curic from Institute of Physics, St Cyril and Methodius University, Skopje, Macedonia, Institute of Meteorology, University of Belgrade, Serbia
Abstract: We examine sulfate production and wet deposition over a rural location in Macedonia using a cloud chemistry model and ground-based measurements. The results indicate that using high- resolution meteorological input data from the WRF atmospheric model produces a better simulation and more realistic representation of the cloud-chemistry processes. The method shows a better skill in representation of convective scale processes, the spatial distribution of chemical fields in the cloud environment and thus a more accurate quantitative assessment of sulfate concentration and pH values. Analysis also indicated that scavenging and oxidation are the principal processes affecting sulfate production, participating with 33% and 46%, respectively. Turning off the ice-phase processes leads to overprediction of sulfate aerosol production for about 8 % relative to the base run. This novel method of initialization based on WRF conditions provides a scientific contribution by evaluating simulations of convective clouds in Macedonia against ground-based meteorological and chemical data, as well as by using the model to understand the driving processes affecting sulfate production and wet deposition. read more... read less...
Keywords: Cloud-chemistry model, WRF initialization, sulfate aerosol, wet deposition, acid precipitation
Remote Sensing Based Water Surface Extraction and Change Detection in the Central Rift Valley Region of Ethiopia
SWES, volume-09, Issue 1 (2017) , PP 01 - 07
Published: 16 Jan 2017
by Amare Sisay from School of Natural Resources and Environmental Studies, Wondo Genet College of Forestry and Natural Resources, Hawassa University, Hawassa, Ethiopia
Abstract: Recent advancements in water indices techniques and the availability of multi-temporal and multi-spectral imageries, has made the task of extracting and detecting surface water changes a lot effective and simpler. By taking advantage of this advancement, this study has therefore implemented NDWI and AWEI, among other indices, to extract and analyze the surface area changes of Lakes Shala, Abjata and Langano in the Central Rift Valley Region of Ethiopia. In doing so, Landsat images of 1973 (MSS data), 1986 (TM), 2000 (ETM+), 2005 (ETM+), 2011 (TM) and 2014 (OLI_TRIS) has been used. The results show that Lake Shala and Lake Langano has shown very small changes (-3.68 sqkm & -10.2 sqkms respectively) as compared to the surface area change of Lake Abjata (-68 sqkm) between 1973 and 2014, hence making Lake Abjata the most abruptly changing lake in four decades. read more... read less...
Keywords: Change Detection, Remote Sensing, surface water extraction, Water indices, Lake Abjata, Lake Shala, Lake Langano.