Browsing by Author "Himat, Abobakar"

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Ancient Karez System in Afghanistan: the Perspective of Construction and Maintenance
(2019) Himat, Abobakar; Doğan, Selim
Ancient Karez has a history of millennium. Karez is underground tunnel which is constructed in ground by digging the main well of the system and extending underground tunnel in foothills of the mountains. This system extracts groundwater to surface by gravity without using any pumping equipment. Ancient Karez system is viable in hot, arid and semi-arid climate regions. These systems are one of the best ways of extracting groundwater by gravity in such poor regions. Minimum slope is vital for extracting groundwater to the surface in Karez system. In this study, the perspective of construction and maintenance of Karez system in Afghanistan is assessed. Information related to Karez construction and maintenance is provided in order to improve the quality of work during these processes. The Karez system cannot be used effectively if construction and maintenance processes are not carried out properly. This will affect agricultural productions, water supply and social life in the region. Some possible solutions are suggested for the mitigation of the risk of collapsing and extinction of Karez systems. Some recommendations are provided to encourage the associated organizations in Afghanistan for rehabilitation of Karez irrigation and water supply system.
Citation - WoS: 1
Citation - Scopus: 1
The Impact of the Regularization on the Economic Analysis of Rooftop Rainwater Harvesting System
(Iwa Publishing, 2023) Himat, Abobakar; Dogan, Selim
In this study, the economic feasibility of rooftop rainwater harvesting of residential and public/commercial buildings for all 81 provinces of Turkiye is assessed. The Rippl method (RM) is used for optimal storage tank estimation. The net present value (NPV) and the discounted payback period (DPP) are used for economic analysis. Two scenarios were assessed using RM for (I) residential buildings and (II) public buildings. Optimal storage tanks for scenarios I and II were estimated by the selection of minimum roof areas to supply the demand for toilet flushing water for above 95% volumetric reliability. ArcGIS 10.2 was used to illustrate nationwide results of (1) roof areas and storage tank volumes, and (2) the economic analysis. The average DPP of rainwater harvesting system is 36 years for residential buildings and 23 years for public buildings. Based on NPV analysis, 17 out of 81 provinces are economically feasible for residential buildings. The feasibility status in public buildings is 43 economically feasible and 38 infeasible. More savings in public buildings can be obtained in a relatively shorter DPP. Furthermore, regularization is more effective in public buildings than residential buildings.
Rooftop Rainwater Harvesting Optimization in Antalya, Turkey
(2019) Himat, Abobakar; Doğan, Selim
The water resources of the world are consuming rapidly due to the population increases and growing industrializing world. Sustainable water resources management seems a solution for managing the scarce water resources. Rainwater harvesting can reduce water shortage problems, especially in countries which suffer from water scarcity. Saving of freshwater resources is essential for water conservation. In domestic uses, the non-potable water demand especially in toilets flushing can be changed with rainwater harvesting. In this study, Water Balance Model (WBM) and Rippl Method (RM) are used to investigate the optimization of rooftop rainwater harvesting in Antalya province of Turkey. The reliability analysis of the rooftop rainwater harvesting and optimal storage estimation analysis have done for system optimization. Comparisons among annual, eight, seven and six months regularizations are made in order to make the rainwater harvesting system feasible and cost-effective. For Antalya rooftop rainwater harvesting system, individual houses (a 6 household family water demand for toilets flushing 24 L/ca/day) are assessed by using the WBM and RM. For optimal rainwater storage tanks estimation 60, 40 and 35 m2 rooftop areas are selected for annual, eight, and seven/six months regularizations respectively for supplying the water demand of toilets flushing with 90-100% reliability. Comparisons between two methods for optimal rainwater harvesting storage tanks are made in order to recommend a suitable method for storage tanks estimation. For annual regularizations, 21 m3 and 17 m3 storage tanks are estimated with RM and WBM respectively. Thus, WBM is recommended for Antalya province. For eight, seven and six months regularizations with RM; 9, 7, and 4 m3 storage tanks are estimated respectively. The storage cost and payback period for annual regularization is 3600 TL and 24 years respectively. Storage, costs about 50% of the rooftop rainwater harvesting. Hence, twofold of storage cost might give the cost of the rooftop rainwater harvesting system.
Urban Drainage Design According To Turkish Rainwater Harvesting and Disposal Guideline
(2019) Himat, Abobakar; Onüçyıldız, Mustafa; Doğan, Selim
The natural cover of land has been changed to impermeable layers in most of the cities with rapid urbanization. The impermeable layers are the drivers of urban floods. Urban areas are becoming prone to flood disasters. The rate of infiltration is higher in natural land cover and lower in impervious surfaces. In impervious surfaces, the high rates of runoff are responsible for urban flood disaster. Runoff in urban areas might be one of the restrictions for drainage during the intense rainfall events. Hence, for accurate drainage design, factors which affect the drainage should be taken into consideration. In urban areas integrated green infrastructure design is one of the most effective tools for stormwater management and runoff reduction. There is a need for water sensitive urban designs for flood risks mitigation. Identification of flood-prone regions is crucial for flood mitigation. Improving permeable paving and sustainable drainage system can reduce floods in urban areas. In this study, Barış Street in Selçuklu district of Konya province is selected for rainwater drainage design using rational method according to the rainwater collection, storage and discharge systems regulation which published in 2017. The study area covers 11.04 ha. The study area has many grey infrastructures and there is no green infrastructure existed. Hence, it is prone to urban flood. Intensity Duration-Frequency (IDF) rainfall curves were used for the intensity and frequency determination. Seven different periods, namely 2, 5, 10, 25, 50,100 and 200 years were selected for rainfall drainage design. Rainfall intensity determination was based on 15 minutes of rainfall. Rain yield was calculated for each period. The required diameters of pipes for drainage are calculated for the selected periods according to 60% full rates. As a result, 400 mm diameter for 2 years, 500 mm diameter for 5, 10, 25 years and 600 mm diameter for 50, 100, 200 years periods have been found as appropriate.