Volume 2 Issue 1
Selection of a Hydrological Model and Objective Function for Water Resources Management in Predominantly Rural Watershed using Criteria-Based Evaluation
Pratik Singh Thakuri, NT Sohan Wijesekera
Selection of a fitting up-to-date hydrological model using an evaluation of the functionality, modeler’s requirements, and modeling experiences are very important for water resources management in rural watersheds. Similarly, the selection of appropriate objective function is equally crucial in hydrological modeling processes. Accordingly, A review study was carried to select an appropriate model and objective function for water resources modeling in the predominantly rural watershed. Hydrological models namely HEC-HMS, MIKE SHE, SWAT, TOPMODEL, and SWMM, and objective functions namely NSE, RMSE, MRAE, and RAEM were reviewed. Hydrological models were reviewed under several criteria viz. temporal scale, spatial scale, hydrological processes, documentation, resources requirement, user interface and, model acquisition cost. Whereas, criteria for the review of objective functions were mathematical implication, flow regime, and modeling purpose. Each of the review criteria was comprised of several factors. The criteria-based evaluation was done to quantify the review outcome of the hydrological model and objective function. SWMM was found to be the most suitable model for simulating rural watersheds for water resources management purposes whereas, MRAE was found to be the most appropriate objective function to evaluate the performance of the model selected for rural watershed modeling.
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Wastewater Treatment and Management in Health Sector of Sri Lanka
Eng. Zulfikar Cader
Hospitals are highly populated facilities that function 24 hours a day. They generate a large amount of wastewater through various sources which are very complex and hazardous. Furthermore, the emission of healthcare wastewater into the cities sewerage, rivers and groundwater pollute the entire system. Therefore, disposal of healthcare wastewater without adequate treatment can cause short and long-term ill-effects to the public’s health. An onsite wastewater treatment would give a dual benefit of preventing the release of hazardous materials into other sources and bring the wastewater into the consumption cycle. At present, most countries utilize the treated wastewater to reduce the consumption of potable water. However, the literature review and preliminary studies revealed that wastewater management is poorly practised in the Sri Lankan healthcare sector. Therefore, this paper aimed to identify the extent of wastewater treatment, utilization and management in Sri Lankan state sector hospitals. The aim of the paper was achieved through a literature review and questionnaire survey. The required data were collected from nine state hospitals in Colombo. Findings of the study revealed that a high quality of wastewater treatment and efficient reuse of reclaimed water is a big challenge for the healthcare sector due to the complex nature of the wastewater process, higher cost of treatment and poor management. Moreover, it was found that currently wastewater generated from the state hospitals are discharged directly into the city’s sewerage without any treatment. Finally, this paper discusses the current level of wastewater treatment, utilization and management in the state hospitals and identifies the critical barriers for the lack of poor practice of wastewater handling.
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Hydrological Modelling Studies of Paravar River Basin, a Tributary of River Godavari using HEC-HMS Model Data
Chandra Sekhar Matli, Vinay S. Hunashal
The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) is designed to simulate the complete hydrologic processes of dendritic watershed systems. The software includes many traditional hydrologic analysis procedures such as event infiltration, unit hydrographs, and hydrologic routing. The model is applied to the Pravara River Basin, which is a tributary of the Godavari River in the Ahmednagar district of Maharashtra (India). For the simulation of runoff, the daily precipitation data and daily observed streamflow data from 1999 to 2012 was collected and ten years of data from 1999 to 2008 was used for the calibration of the model and 4 years of data from 2009 to 2012 was used for the validation of the model. The calibration of the HEC-HMS 4.0 model for the study area is carried out by comparing the simulated daily streamflow with the observed flow at the outlet of the basin. For this particular study, the deficit and constant loss model is used to compute the losses from the watershed. Under prediction of high flows is an inherent problem seen in hydrological modeling of the basin in the present study. This is due to the lack of extreme event modeling capability of the hydrological model. The daily flows except extreme flows are better simulated. The ability of HEC–HMS to simulate the magnitude of the peaks in extreme floods in the river basin underscores the significance of the model application as a flood prediction tool. The HEC–HMS successfully reproduced low flows and thus the model is a useful tool to estimate low flows in advance based on drought forecasts.
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Manual Multi purpose Machine for Drip cum Plastic Mulch Laying and Recollection for Reuse in Crop Production
Mintu Job, D.K. Rusia, S. R. Bhaskar
Plastic mulching is a soil moisture conservation method that involves placing poly film over raised or a flat bed to provide a more favorable environment for growth and production. Plastic mulch normally is used in conjunction with drip irrigation to maintain optimum soil moisture and for improved stand establishment. Plastic film mulching with drip irrigation is a proven technology for vegetable production and its popularity is ever increasing among vegetable growers. Mulches leave behind large amount of plastic in the soil which in the current practice is buried or burned in the field which are both hazardous to environment. So, a mechanism is to be developed for retrieval of mulches for reuse or recycle. Basic mulch laying technique should include that mulch is stretched and placed firmly against compacted soil and edges of mulch are properly buried under soil, so, that wind can’t loosen them. Tractor operated mulch laying machine in available but its use is limited to large areas and where crop spacing allows it as area lost in between two rows is very large. To suit the requirement of small farmers partial mechanization of laying of mulch film is envisaged by developing a Manual Multipurpose trolley for plastic mulch laying and recollection. This machine besides being simple in design and operation also caters to a very important operation, which is otherwise overlooked, that is of retrieving the used plastic mulch by rolling it back for better storage which significantly enhances its life beside being environment friendly.
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Assessment of Climate Change Impact on the Hydrology of the Kabul River Basin, Afghanistan
Massouda Sidiqi, Sangam Shrestha
Climate change and variability affect the availability and management of water resources and the hydrological cycle, especially in arid and semi-arid regions. This research was conducted to analyse the impact of climate change on the hydrology of the Kabul River Basin, Afghanistan by using the outputs of three General Circulation Models under two representative concentration pathway scenarios: RCP 4.5 and RCP 8.5. Future climate data (precipitation and temperature) obtained from the climate models were bias-corrected using the delta change approach. Maximum and minimum temperature and precipitation were predicted for the three future periods: 2020s (2010–2039), 2050s (2040–2069), and 2080s (2070–2099) against the baseline period 1961–1980. The o o o mean annual temperature in the basin is projected to increase by 1.8 C, 3.5 C, and 4.8 C in the 2020s, 2050s, and 2080s, respectively. The projected annual precipitation is expected to decline by approximately 53 to 65% for the whole river basin under both scenarios in the future period. The well-calibrated and validated Soil Water Assessment Tool (SWAT) was used to simulate the future streamflow in the basin. The mean annual streamflow is projected to increase by 50 to 120% in the future. This study provides valuable information for guiding future water resource management in the Kabul River Basin and other arid and semi-arid regions of Afghanistan.
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