Feasibility study, detail design and construction supervision metehara town

The project involves water system feasibility study, detail design, preparation of tender document and business plan, ESIA, sanitation facilities assessment and design, Business Plan Preparation updating of the performance agreement and capacity building, and construction supervision and contract management for Metehara Town: District Capital of Fentale Woreda of East Shewa Zone with population of over 36,000 in 2030.

The project intends to upgrad4e the current water supply system that had been constructed between 2002-2004 to serve for 10 years.

The town Water Supply System is Consists of Intake structure on Awash River, treatment plant[4000m3/day], booster pumping station, header tank, Clear Water Tank, Service reservoirs, transmission and distribution network system.

The treatment plant process consists of trey aeration, coagulant dosing, and flash mixing, upflow clarification, rapid sand filtration and disinfection.

After detail assesment of existing situation and identified major shortcommings design of water supply system that caters for population of 58,468  in 2031 and 82,639 in 2041 is designed by integrating with existing system for a capcity of 9,808 m3/day (114 l/s) in 2031 and 17,115m3/day (198 l/s) in 2041 for Intake and Treatment Plant design, while the clear water pumping station, transmission and distribution reservoirs are sized for 106.1l/sec and 185lt/sec 1st and 2nd phases maximum day demand.

Source Assessment & Study

As part of the water source assessment and investigation both fluoride free ground water investigation and surface water study and assessment on the existing surface water source on Awash River have been conducted.

The ground water option had been meant to reduce the future water stress to be encountered on Awash River, which currently supplies around 11 large scale  irrigation schemes and 6 drinking water supply sources for medium to big towns relying on the Awash River.

Based on geological, hydrogeological, water point inventory and geophysical investigation recommended a potential site for future source development and recommended for the development of test well upstream of the existing intake. Hower; due to the Rfift Valley water chemistry; it has been proposed to abstract deep regional ground water while grouting the top 200-250m top aquifer.

However; during feasibility stage; it  have been decided to prioritize the upgrading of existing surface water sources on Awash River by the Client.

Detail Hydrological studies have been undertaken on the Awash River to determine source adequacy and confirmed. After that, three options were analysed for Intake Design i)Existing Intake Rehabilitation ii)New Intake design at existing intake Site iii)New Intake Site Development.

After though analysis of options, it has become clear and imperative to abandon the existing intake, and go for side intake upstream the existing intake with much less cost and more water abstraction potential. Thus, New Headwork design for over 200lt/sec has been design with new desilting basin and wetwell.

• Headwork and intake structures (wet well receiving raw water by gravity from the river side intake and submersible drainage pumps installed in the wet well to pump the raw water to the raw water header tank at the treatment plant;
• Water Treatment Plant which includes Cascade Aeration, Plain Sedimentation, Hydraulic Mixer and flocculator, Sludge Blanket Clarifier (Upflow Type), Rapid Sand Filter, Elevated Backwash Tanker, Clear Water Tank, clear water pump station housing the clear water pumps, backwash pumps and air blowers, chemical building and associated chemical preparation and dosing equipment, standby generator & a transformer house, control room within plant piping, electrical system and control system and site works;
• Supply and installation of 0.42km uPVC OD350 and 12.8km uPVC OD400 PN16 raw water and clear water transmission main pipelines respectively;
• Construction of 800 m³ capacity reinforcement concrete ground service reservoir;
• Supply and Installation of electro-mechanical equipment works at raw water intake and treatment plant;
• Supply and laying of 42.9km and 41.4km distribution network pipelines ranging from OD50 to OD500 HDPE & uPVC Pipes during Phase-I and Phase-II respectively;
• Construction of four (04) public fountains, guard houses, VIP latrine at service reservoir and two public latrine and shower rooms with septic tanks.