African Journal of Water Conservation and Sustainability

African Journal of Water Conservation and Sustainability ISSN 2375-0936 Vol. 9 (4), pp. 001-016, April, 2021. © International Scholars Journals

Full length Research Paper

Factors Affecting the Sustainability of Wateryards in Western Sudan

Hamid Omer Ali

Hydrotech Consult, Sheikh Amin building, POB 1875, Khartoum, Sudan.

Accepted 05 April, 2021 

Abstract

Wateryards are the most common water supply source in western Sudan. Components of a wateryard include: a borehole fitted with an engine-driven pump, an elevated tank, animal watering troughs and taps for human use. Despite efforts to rehabilitate and upgrade the functionality of wateryards, their sustainability- in terms of water productivity (quantity), quality, accessibility, reliability and the affordability of the water produced - was short-lived. Within a few years most wateryards had deteriorated to their pre-rehabilitation condition. Factors such as the quantity of livestock that rely on the wateryards, the extent of (excessive) use, the yield potential, the existence of nearby alternative water source(s), the degree of community participation in the management of the wateryard, the misuse of water revenues, and the ready availability of fuel and spare parts all had an impact on the sustainability of the rehabilitated wateryards in western Sudan. With due consideration to these factors, sustainable water supply sources cannot be achieved without considering technical, institutional, environmental, economic and social factors within the broader context of the key principles and good practices of Integrated Water Resources Management (IWRM).

Keywords: Kordofan State; Sudan; Water supply systems; Sustainability of wateryards.

African Journal of Water Conservation and Sustainability ISSN: 2375-0936 Vol. 9 (4), pp. 001-008, April, 2021. © International Scholars Journals

Full Length Research Paper

Determination of appropriate hydraulic conditions to decrease the negative impacts of Dez dam flushing operation on the downstream

H. Samadi-Boroujeni¹*, A. H. Haghiabi² and E. Ardalan³

¹Water Engineering Department, Shahrekord University and Water Recources Research Center, Iran.

²Water Engineering Department, Lorestan University, Iran

³Water Engineering Department, Shahrekord University, Iran, Msc Water Engineering Graduated from Shahrekord University, Iran

Accepted 11 November, 2020

Abstract

The Dez dam is located in the Southwest Iran and was constructed in 1963, with a height of 203 m and an underground powerhouse of 520 MW, because of the high rate reservoir sedimentation, in recent years, therefore, performing flushing operations through the three irrigation gates of the dam has received great attention. Due to the release of high concentrations of sediments, on the other hand, performing such operations may cause considerable impacts downstream. The downstream limitations should, therefore, be taken into consideration during the flushing operations. In this paper, it has been tried to identify and introduce the downstream limitations of performing flushing operations for Dez dam, and to determine the most appropriate flushing hydraulic conditions in terms of discharge, concentration, and duration of such operations using model MIKE 11, so that the dam utilization system can perform these operations with the least damage to the downstream. Results show that if we take into consideration every factor involving the decision - making, then the flushing operations along with two stages of opening the irrigation gates (that is the evacuation of sediments) for 6 hours and the discharge of 30 m³/s will be the best option. The interval between the two flushing operations should be at least 6 hours. Based on the results of this paper, appropriate conditions for hydraulic flushing can be determined. These conditions will be manipulated by the responsible administration as these operations would have the least damage and cost.

Key words: Dez dam, environmental impacts, sediment flushing, Mike 11 model.

African Journal of Water Conservation and Sustainability ISSN: 2375-0936 Vol. 9 (4), pp. 001-008, April, 2021. © International Scholars Journals

Full Length Research Paper

Scouring control of the eroded stilling basin: Case study, Namrood Dam

H. Taebi and M. Fathi-Moghadam*

¹Graduate Student, School of Water Sciences Engineering, Shahid Chamran University, Ahwaz, Iran.

²School of Water Sciences Engineering, Shahid Chamran University, Ahwaz, Iran.

Accepted 15 October, 2020

Abstract

Local scouring immediately downstream of stilling basin is unavoidable local velocity exceeds incipient motion velocity. This phenomenon causes a difference level between concrete floor of basin and river bed. In such circumstances a riprap is normally used to prevent the development of scouring hole. In this study, hydraulic model of Namrood dam is used to estimate stone size that is able to resist scouring as result of basin turbulent outlet flow. Tail water (y_t), the difference in level between basin floor and river bed (Z) and critical depth of flow in stilling basin (y_c) are required to be measured in order to develop a mathematical model for estimation of scouring. Results confirm considerable reduction of the stone size with increase of (Z) and (y_t) for same flow discharges, while stone size increases with flow discharge.

Key words: Riprap protection, stilling basin, hydraulic jump, stability number.

African Journal of Water Conservation and Sustainability ISSN: 2375-0936 Vol. 9 (2), pp. 001-009, February, 2021. © International Scholars Journals

Full Length Research Paper 

A study of sand filter capping for turbidity removal for potable water treatment plants of Mosul/Iraq

S. M. Al-Rawi

Environment Research Center (ERC), Mosul University, Mosul, Iraq. E -mail: [email protected].

Accepted 13 September, 2020

Abstract

Sand filter capping had been tried as an alternative for the currently practiced rapid sand filters. A 1000 m³/day capacity pilot plant constructed similarly to full scale water treatment plants was used for this purpose. Four levels of sand material with respect to grain size and thickness were used. Capping filter was represented by one level of anthracite coal with one thickness. In order to optimize the most efficient combination(s) of the two materials for maximum filter performance in terms of quality and quantity, four filtration rates were tried. A series of forty test runs and experiments exceeding 120 using different filter configurations were tried. Filters were operated in pairs and subjected to the same conditions. Filters consisting of 20 cm anthracite coal (0.91 mm E.S.) over 40 cm of sand (0.69 mm E.S.) appeared to be the best fit configuration among tried filters. Considerable economical consequences could be achieved using sand filter capping. This was reflected in reducing filter numbers or increasing the plant capacity by two folds in the minimum. Economic revenue was gained through reduction of disinfection doses as well as reduction in filter sand material. Runtimes of filters were increased by 2 - 3 folds indicating capability of more furnished water productivity and less amount for backwash need. Above all the water produced was of very good quality that met the most stringent specifications and promoted health. Capping sand filters were proven to suitably operate under varying conditions of influent turbidity and filtration rates.

Key words: Drinking water filtration, rapid sand filtration, dual-media filtration, multi-media filters, water treatment, filter media, gravity filtration.

African Journal of Water Conservation and Sustainability ISSN: 2375-0936 Vol. 9 (1), pp. 001-010, January, 2021. © International Scholars Journals

Full Length Research Paper

Hydrological modeling approaches for the Kihansi river catchment in south central Tanzania

Birhanu Zemadim Birhanu

Water Resources and Environmental Engineering Department, Bahir Dar University, P. O. Box 26, Bahir Dar, Ethiopia.

E-mail [email protected]. Tel: +251910457450. Fax: +251582202027

Accepted 11 September, 2020

Abstract 

This study presents distributed and lumped hydrological modeling approaches for the Kihansi river catchment in south central Tanzania using the Soil and Water Assessment Tool (SWAT). The catchment is source of water for the Lower Kihansi Hydropower Plant (LKHP) that supplies 25% power to the national grid and the bio-diverse gorge eco-system in lower Kihansi Basin. In the distributed modeling sub-watersheds were defined at the existing gauging stations. There are four upper sub-watersheds and ten sub-watersheds located downstream. Three sub-watersheds of the river system were separately modelled in a lumped approach. Subsequent parameterization of physically-based soil parameters, landuse, and management files were defined. Four quantitative and two qualitative evaluation criteria were used to evaluate the prediction performance of SWAT model. Model prediction results using unoptimized parameter sets resulted poor modeling performance. Hence parameter specification and optimization was necessary to ensure correct hydrological processes. Modelling results using optimized parameter sets resulted better prediction of hydrological variables. Finally correction factors were introduced for optimised parameters to facilitate future land cover change studies.

Key words. Hydrology, modeling, SWAT, Kihansi river, calibration, validation.