E863 Volume 2 FEDERAL REPUBLIC OF NIGERIA FEDERAL MINISTRY OF WATER RESOURCES Public Disclosure Authorized NATIONAL URBAN WATER SECTOR REFORM PROJECT (NUWSRP) Public Disclosure Authorized Public Disclosure Authorized j,?.,i~~~~~~~~~~~~~~~~ DAM SAFETY MEASURES REPORT MARCH 2004 Public Disclosure Authorized a-'''FLE COP Table of Contents Paae No. 1.0 Introduction 3 2.0 Record of findings from Dam Inspection of a Sample of the Dams. A 3.0 Recommendations ..14 4.0 Cost Estimates ..17 Appendices: Annex A: Gantt Chart ..18 Annex B: Reservoir Survey Equipment ..19 Annex C: TORs for Assessment of Sedimentation Strategies for Reserviors ..22 2 1.0 INTRODUCTiON 1.1 Scope of this Report It is beyond the scope of this report to present details of the existing structural and safety status of each dam, together with details of the engineering and technical solutions for addressing any issues of safety. This requirement is part of the recommendations of this report. However, the scope of this report is to develop a set of actions that are to be implemented as part of the Nigeria Urban Sector Water Reform Project (NUSWRP) to ensure that the existing dams supplying raw water to the participating State Water Boards operate safety. Therefore, the methodology used to determine what these actions should be was based on reviewing existing Dam Safety literature and other available technical reports from the participating state water agencies and river basin authorities, interviews of their key technical staff, followed by site inspections of a representative sample of the Dams in the list contained in Section 1.8 of this report, viz-a-viz, the Dam Safety Operational Policy 4.37 of the World Bank and the specific objectives and limitations of the proposed NUWSRP. The environmental issues associated with these dams and this project is also beyond the scope of this report and is addressed separately in the Environment and Social Management Framework (ESMF) for this project. 1.2 Brief Background of the Water Sector In Nigeria The problems facing the water supply sector in Nigeria are many, characterized by acute shortage of supply, even though Nigeria is blessed with abundant water resources estimated at 226 billion m3 of surface water and about 40 billion m3 of ground water. One projection of Nigeria's population estimates that it will reach the level of 338 million by the year 2050. If this estimate and other country estimates are correct, Nigeria would move from 10th most populous country in the world to the 4' most populous country in a short span of just under 50 years. For example, out of the 85 million people living in urban and peri-urban areas, less than half have reasonable water supply. Many households, often the poorest, end up purchasing water from private vendors at a much higher charge than from the public supply. Moreover, water supply services where they exist are unreliable and of low quality and are not sustainable because of difficulties in management, operation and pricing, and failure to recover costs. Also, many water supply systems show extensive deterioration and poor utilization of existing capacities, due to under-maintenance and lack of funds for operations. Additionally, the high cost of imported equipment especially in terms of a depreciating currency, and inadequate cost recovery policies have contributed to large financial deficits in many State Water Agencies (SWA's). This has left most SWA's dependent upon state subventions to finance operations and maintenance of their water systems, to service debt and to finance new investments. The Federal Govemment of Nigeria and the states are totally committed to address this problem. Water has a top priority in the govemment's development agenda, mainly due to the cross-cutting impact of safe water on health, productivity, and quality of life, with serious implications for poor and vulnerable communities. Therefore, the govemment of the Federal Republic of Nigeria is working to address these problems by recognizing the need to manage the water sector in an integrated and sustainable 3 circumstances fund the construction of new dams, large or small. However, the operations of the State Water Agencies (SWA's) depend either on the use of existing dams run, operated and owned by themselves, as in some states or as in other states by the River Basin Development Authority (RBDA) of that state, for one or a combination of the following functions: i) as a reservoir ii) to manage water flow and levels in rivers iii) provision of raw water to SWA's iv) Generation of Hydro-Electric power. 1.7 Applicability of the Banks Operational Policy OP 4.37, Safety of Dams The Bank may finance types of projects that do not include a new dam but will rely on the performance of an existing dam such as water supply systems that draw directly from a reservoir controlled by an existing dam, diversion dams or hydraulic structures downstream from an existing dam, where failure of the upstream dam could cause extensive damage to or failure of a new Bank-funded structure; and or irrigation or water supply projects that will depend on the storage and operation of an existing dam. Projects in this category also include operations that require increases in the capacity of an existing dam, or changes in the characteristics of the impounded materials, where failure of the existing dam could cause extensive damage to or failure of the Bank-funded facilities. Therefore, for participating SWA's that involve the use of existing dams as described above, the Bank requires that the FMWR arrange for one or more independent dam specialists to: (a) inspect and evaluate the safety status of the existing dams or their appurtenances, and its performance history; (b) review and evaluate the owner's operation and maintenance procedures; and (c) provide a written report of findings and recommendations for any remedial work or safety-related measures necessary to upgrade the existing dams to an acceptable standard of safety. The Bank may accept previous assessments of dam safety or recommendations or improvements needed in the existing dam if the FMWR provides evidence that; (a) an effective dam safety program is already in operation, and (b) full-level inspections and dam safety assessments of the existing dam, which are satisfactory to the Bank, have already been conducted and documented. As the state water agencies of the participating states rely on the provision of raw water from the management of several dams that either supply water directly to their water treatment plant and/or through controlled releases of water from the dams into the rivers upstream of raw water intake at the treatment plant, the Banks OP4.37, Safety of Dams, applies to this project. OP 4.37 Dam Safety requires the Federal Govemment of Nigeria (FRN) to prepare a Dam Safety Measures Report (i.e. this report) to address safe and sustainable management and operations of the Dams that will be supplying raw water to the participating state water boards. OP 4.37 also requires the FRN to include in the Dam Safety Measures report; other Dams 5 supplying raw water to the states that are not being financed in this project by the Bank directly, but are included in the project anyway, even though they are financed from other (non-bank) sources. This report and the Environmental and Social Management Framework (ESMF) will be disclosed as separate and stand alone documents at the World Bank's infoshop and in Nigeria. The ESMF was disclosed before the project was appraised by the bank and this report will be disclosed before this project is presented to the Board of the Bank for approval. 1.8 List of Dams in Participating States KANO STATE Name of Dam Year Built Height (m) Reservoir (Mm ) SpillwayT Ado Bayero Audu Bako - Baguada 1970 21 22.14 Uncontrolled Birmin Kudu - 8 2 Bunga - - Challawa Gorge 1977 40 969 Uncontrolled Dogwala Dudurun Gaya - Garanga Gari 1980 22 214 Uncontrolled Gulka _ _ ._ Guzuguzu 1979 17 24.6 Box Culvert Hajiya Ladi Bako - _ __ Ibrahim Adamu 1974 9 8 Controlled _ggi_ - - Jakara 1976 14 65.2 Uncontrolled Kafia - _ - Kafin Chari 1977 16 31.1 Ogee Crest Kango - 15 8.73 Box Culvert Kara Chada - _ Kara Duwa - - _ Karaye 1971 15 17.2 Uncontrolled Katini - - . Keffin Gana Kiwia _ Kiyako - Koreyel Kunza - Lower Mareshi - Magaga 1980 19 t19.7 Uncontrolled Mareshi 1980 _1 1 6.77_B. Uncontrolled Marke - - Misau 6 Mahammadu 1975 16 5.53 Box Culvert Ayuba Pada 1980 14 12 Uncontrolled Ruwan Kanya 1976 22 Uncontrolled Shimar - ___ Tiga 1975 47 1968 Uncontrolled Tomas 1976 14 60.3 Box Culvert Tudun Wada 1977 21 20.8 Uncontrolled Tukurua - - Warwade - 10 12.3 Box Culvert Watari 1980 20 104 Uncontrolled Yakubu Gowon - ___ Kaduna State Birnin-Gwari 1975 14 4 Uncontrolled (Bogoma) _ Kangimi 1977 20 58 Uncontrolled Zaria 1975 14 15.3 Uncontrolled Ogun State Oyan 1183130 = =270 | Gated Ikere Gorge 1991 50 -|630 |Uncontolled Plateau State Yakubu Gowon 1982 35 30 Uncontrolled Pankshin 1982 29.5 4 Uncontrolled Langtang 1982 21 4.6 Uncontrolled Shendam 1984 13 4.5 Bokkos Uncontrolled 1985 - 0.1 Uncontrolled Liberty 1972 27 20 Uncontrolled Kogingiri 1934 8.23 0.1 Uncontrolled Lamingo 1935 11.28 0.1 Uncontrolled Tollemarch 1961 7.64 0.1 Uncontrolled 7 2.0 RECORD OF FINDINGS FROM DAM INSPECTION OF A SAMPLE OF THE DAMS. These dams are water supply earthfill embankmenta dams. The review of the safety of these dams looked at the following areas; * Availability of reliable records of Dam operations, rainfall data, as-built drawings, etc. * Existence of Dam Operational Manuals, and its implementation.