Performance Evaluation Of An Existing Multi-Village Piped Water Supply Scheme And Identification Of Intervention Mechanisms, The Case Of Teyfe Water Supply Project In Ethiopia

Abstract

Water Is One Of The Basic Elements For The Sustenance Of Human Life; However, The Water Supply Coverage In Ethiopia Accounts Only 49%. Beside Low Scheme Coverage, The Poor Performance And Scheme Unsustainability Become A Problem To Manage The Ever Increasing Demands. Teyfe Multi-Village Water Supply System Was Constructed To Give Service For 69,699 People Living In Eight Kebeles And Two Rural Towns. Frequent Breaking Of Pipes, Uneven Water Distribution And High Energy Consumptions Are The Problems Identified For Which This Research Was Conducted. . Analysis Of Demands For The Design Period Of The Project, Performance Evaluation Of The Major System Components And Identification Of Intervention Mechanisms For The System Improvements Were The Specific Objectives Of This Studies. Demand Was Computed For The Proposed Design Period Using Projected Population And Unit Rate Consumptions Considering Different Mode Of Services. erformance Evaluation Of Eme, Reservoirs And Source Were Carried Out Comparing The Existing Component Capacity Against The Capacity Of The Computed Using The Respective Standard Equations And National Guide Lines. Hydraulic Analysis Was Conducted Employing Watergems Software To Evaluate The Pressure And Velocity Of Both Transmission And Distribution Pipe Lines. Sample Surveying Was Also Conducted To Assess The Utility Management Potential. From Result Of The Demand Analysis, 40.78 L/S Maximum Day Demand (Mdd) Is Required To Address The Water Supply Coverage For The Intended Design Period. Regarding System Component Performance, The Source Has A Discharge Capacity Of 61.8 L/S And Sufficient For Project Life Time. However, Only 30 L/S, Accounting 73.56% Of Mdd, Is Currently Taken From This Source. Distribution Lines Nodes Were Exposed To High Pressure (883 M), Which Can Break Pipes; Moreover, 51.43% Of The Pipe Has Velocity Less Than The Recommended 0.6 M/S, Which Might Result In Stagnant Water Formation. All Existing Reservoirs Were Evaluated And Found Sufficient To Balance The Mdd Required. Regarding Electro-Mechanical Equipment (Eme), Pumps At Station Wet Well 1, 2 And 3 Can Give Full Service Up To 2032, Supplying 30 L/S And The Pump In Wet Well 4, With Discharge 12.5 L/S, Serves Only Up To 2027. All Associated Power Plants, With The Exception Of The Generator In Wet Well 4, Were Designed Oversized And Subjected ToHigh Energy Consumption. Furthermore The User Community Has Not Yet Completely Utilized The System Due To Long Distance Travelled (>1km) To Collect Water And The High Water Tariff (100 Birr/M3) Accounting 65.95 And 99.02 %, Respectively And Hence Low Customer Satisfaction Achived. Substantial Loss Of Water (46%) Also Indicates Poor Water Resource Management Of The Utility. As An Intervention Mechanism Optimized Pipe Layout Was Proposed To Minimize The Energy Consumption Of Power Plant And Control Valves Of Different Kinds And Chambers Used To Reduce Static Pressures And Remove Silts Were Also Suggested. Preparation Of Adequate Business Plan Used To Enable Utility To Improve System Management Was Also Recommended.