SUPPORTING REPORT 6 WATER RESOURCES MANAGEMENT PLAN WATER RESOURCES MANAGEMENT PLAN Water Resources Management Plan SR6.1 Operation and Maintenance of Existing Dams SR6.1.1 Enhancement of Dam Management SR6.1.2 Dam Safety Management SR6.1.3 Basic Concept for Dam Modification/Rehabilitation SR6.2 Hydrological Monitoring SR6.2.1 Nigeria Hydrological Service Agency (NIHSA) SR6.2.2 Hydrological Monitoring for Surface Water SR6.3 Consideration of Risk Associated with Climate Change and Trans‐boundary Waters SR6.3.1 Climate Change SR6.3.2 Trans‐boundary Water SR6.3.3 Coping Strategy on Risk associate with Climate Change and Trans‐boundary Water SR6.4 Water Environment Management SR6.4.1 Water Environment Conservation SR6.4.2 Water Quality Management SR6.4.3 Problems and Issues on Water Environment Management SR6.4.4 Proposed Plans for Water Environment Management Improvement SR6.5 Water Allocation and Regulation SR6.5.1 Current Condition and Issues on Water Allocation and Regulation SR6.5.2 Proposed Framework on Water Allocation and Regulation SR6.5.3 Proposed Projects The Project for Review and Update of Nigeria National Water Resources Master Plan Contents Page SR 6.1 Operation and Maintenance of Existing Dams ................................................................. SR6-1 SR6.1.1 Enhancement of Dam Management .................................................................................... SR6-1 SR6.1.2 Dam Safety Management.................................................................................................... SR6-4 SR6.1.3 Basic Concept for Dam Modification/Rehabilitation ......................................................... SR6-7 SR 6.2 Hydrological Monitoring ..................................................................................................... SR6-14 SR6.2.1 Nigeria Hydrological Service Agency (NIHSA) ................................................................ SR6-14 SR6.2.2 Hydrological Monitoring for Surface Water ....................................................................... SR6-17 SR 6.3 Consideration of Risk Associated with Climate Change and Trans-boundary Water ... SR6-30 SR6.3.1 Climate Change .................................................................................................................. SR6-30 SR6.3.2 Trans-boundary Water ......................................................................................................... SR6-32 SR6.3.3 Coping Strategy on Risk associate with Climate Change and Trans-boundary Water ........ SR6-38 SR 6.4 Water Environment Management ...................................................................................... SR6-39 SR6.4.1 Water Environment Conservation ....................................................................................... SR6-39 SR6.4.2 Water Quality Management ................................................................................................ SR6-55 SR6.4.3 Problems and Issues on Water Environment Management ................................................. SR6-60 SR6.4.4 Proposed Plans for Water Environment Management Improvement .................................. SR6-62 SR 6.5 Water Allocation and Regulation ....................................................................................... SR6-69 SR6.5.1 Current Condition and Issues on Water Allocation and Regulation .................................... SR6-69 SR6.5.2 Proposed Framework on Water Allocation and Regulation ................................................ SR6-75 SR6.5.3 Proposed Projects................................................................................................................ SR6-79 Vol ume -5, SR6 (1) The Project for Review and Update of Nigeria National Water Resources Master Plan SR6 WATER RESOURCES MANAGEMENT PLAN SR6.1 Operation and Maintenance of Existing Dams SR6.1.1 Enhancement of Dam Management Constructing dams does not automatically make them work at 100% of their capacities. They are engineering structures designed to function fully with proper maintenance and operations after their completion. In other words, we need to first recognize the fact that dams are engineering structures that cannot perform as designed without proper daily management. Dams serve diverse purposes, including flood control, water supply, irrigation, and power generation. Regardless of the purpose, dams need to be managed with respect to the following basic aspects: Dam structures and facilities Reservoirs Reservoir water level control (high water/low water-level operations) The configuration of dam management for the above is as shown in Table SR6-1. According to the results of the subcontracted survey, no dam in Nigeria is properly carrying out management work that covers all the items listed above. The three major hydropower dams, namely, Kainji, Jebba, and Shiroro, as well as several other dams, are relatively well managed but not to a sufficient degree. Principally speaking, organizational structures and facilities that allow prompt and proper implementation of the above management activities must be in place at the same time when the dams are completed. As the management statuses of the existing dams are extremely poor, we propose to improve the management system starting with high priority dams by following the workflow shown in Figure SR6-1 and Table SR6-2. Table SR6-1 Configuration of Dam Management Contents Item Dam management situation in Nigeria The management of the Dam body, Administrative road, Almost no management has been done. Kainji, Jebba, facility of the dam body Discharge facilities, Water and Shiroro dam and some other dams have been intake facilities, Private power managed, but it is still not completed. generation facilities Management of dam Sedimentation; Water quality; Almost management has not been done reservoir Lakeshore Controlling and operation Reservoir observation and Except Kainji, Jebba, and Shiroro dam, most of dams of the dam reservoir recording; inflow observation have not been managed and recorded. and recording; other hydrological observation and recording; recording of gate operation; Transmission of information to downstream Source: JICA Project Team “Dam Management Manual” is nonexistent in all of the dams, which is one of the reasons for the poor management/maintenance status (in other words, no one knows or understands how to manage the dams). In Japan, establishment of “Dam Operation Rules” is mandatory for all dams constructed, according to which the administrator of each dam properly carries out daily management (for both flood control and water utilization). By referring to these rules, dams in Nigeria are considered to establish their own respective “Dam Management Manuals” that share some common contents. Based on the above, it would be proposed that the dam management manual is unified to some extent in each dam. The items that should be included in the dam management manual are tentatively proposed as shown in Table SR6-3. Vol ume -5, SR6 (SR6-1) The Project for Review and Update of Nigeria National Water Resources Master Plan There is a risk of submerged in the downstream urban area and private house because of dam break or failing for flood control. Yes No Hydrological observation data almost there are hydrological does not exist observation data Yes No Yes No Water demand for the water resources is greater Yes No Reservoir capacity is more than 100 million m3 Yes No Case A Case B Case C Case D Case E Dam body survey Dam body survey Dam body survey Hydrological analysis Hydrological observation Hydrological observation Hydrological observation Hydrological analysis Facilities investigation Source: JICA Project Team Figure SR6-1 Flowchart of Priority for Improving Dam Management Table SR6-2 Categorization of Status on Dam Management Case Survey item Description A Dam body survey ; Because of higher potential damage by the collapse of the dam body, importance Hydrological observation; of irrigation and a relatively large scale, it is necessary to implement as soon as Facilities investigation possible for hydrological observation (rehabilitation), dam body survey and the other investigate of facilities(including machinery, reservoir). B Dam body survey ; Because the scale is slightly smaller than the case A, at present, it is a need with Hydrological observation; emphasis on the investigation to the safety of the dam body and the accumulation of hydrological data (rehabilitation of hydrological observation and observation). C Dam body survey ; Because of the accumulation of hydrological data, Immediately in addition to the Hydrological analysis; dam body survey, it is a suitable dam which be carried out on a priority to hydrological analysis of design flood flow and optimal dam operation, etc. D Hydrological analysis; Because there is no risk of damage caused by dam break and accumulation of hydrological data it is a suitable dam which be carried out on a priority to hydrological analysis of design flood flow and optimal dam operation, etc. E Hydrological observation; Since there is no data and need hydrological analysis, the case is a suitable dam which accumulating hydrological data (rehabilitation of hydrological observation and observation) at first. Source: JICA Project Team Vol ume -5, SR6 (SR6-2) The Project for Review and Update of Nigeria National Water Resources Master Plan Table SR6-3 Tentatively Proposed Items that should be included in Dam Management Manual Major items Small items Contents Remarks Definition