Nouakchott City Urban Master Plan Development Project Final Report CHAPTER 6: UTILITIES INFRASTRUCTURE DEVELOPMENT PLAN 6.1 Water Supply 6.1.1 Existing water supply system and problems (1) Organization The water supply of Nouakchott city is under the jurisdiction of the National Water Corporation (SNDE) of the Hydraulic Department, the Ministry of Hydraulics and Sanitation. In the area where the water distribution network of SNDE is installed in the city, the Corporation is providing water service. In areas where the distribution network is not well developed, 9 administrative communities (Communes) in the city and/or private water venders are providing water service by reselling water of SNDE. (2) Water source The water supply system of Nouakchott city has two water sources, a groundwater source at Iddini located about 60km east of the city and a surface water source of "Aftout Essahli Drinking Water Project" (hereinafter referred to as "Aftout project"), which is a surface water source of the Senegal River. The Aftout project responds to the water demand until 2030 with the aim of solving the water problem which is an obstacle to social and economic development of Nouakchott city. The construction work of the Aftout project commenced in 2007 and completed in August 2010, and the facilities of the project started service in November 2010. In addition to the above groundwater source of Iddini (capacity: 35,000m3/day), 226,000m3/day of surface water source is added as a water source for water supply. Before supplying water from Aftout project, groundwater of approx. 65,000m3/day was taken from Iddini system, however, from the viewpoint of conservation of the groundwater source, the yield of groundwater of Iddini is limited to approx. 20,000m3/day after the service of the Aftout project was commenced. (3) Aftout project The Aftout project constructed a new water intake at Aftout, about 50km upstream from the estuary of the Senegal River, and takes raw water from the river. Raw water taken from the water intake is conveyed to the water treatment plant (the first water treatment plant) located in Béni Nadji, about 6 km from the water intake and the raw water is treated through coagulation and sedimentation processes as a pre- treatment. The treated raw water is transmitted about 170km by pumps and reaches to the water treatment plant (the second water treatment plant) located in the PK17, about 19 km south of Nouakchott city. The pre-treated raw water transmitted from the first water treatment plant is temporarily stored in the raw water storage tank (capacity: 129,000m3) of the second water treatment plant, and then coagulant is dosed into the raw water. Micro-flocs formed in the flash mixer are directly filtrated by the rapid sand filters. In the second water treatment plant, various sensors are installed in the treatment processes, and the operation is centralized in the central control room. Back washing process of the rapid sand filter is also performed automatically. The flow rate, turbidity, water temperature, pH value, etc. at each process of the water treatment are also constantly monitored and quality of the treated water is also controlled properly. (4) Present water supply situation Water service in Nouakchott city is provided by private connections connected to the water distribution network of SNDE, public water station, water tankers and water supply cart of water venders. It is estimated that per-capita water consumption for private connection is 80 lcd (liters per capia per day), 257 Nouakchott City Urban Master Plan Development Project Final Report and 10 to 15 lcd for buying water from vendors. Water purchased from vendors is expensive (3 to 5 times) compared with SNDE's unit water rate, so the amount of water used is limited to the minimum water use of the people. The Aftout project has greatly improved the water supply situation in Nouakchott city. The present water supply amount is below the planed amount due to delays in the construction of the water distribution network, but there is no situation in the city where the water supply amount is insufficient. (5) Water distribution system The existing water distribution network in Nouakchott city was heavily leaked due to the deterioration. For this reason, the network effective rate as of 2011 was 0.42 (estimated by SNDE). It has been gradually improving the network effective rate with the progress of the project for improving water distribution system, “Master Plan for Water Distribution in Nouakchott” prepared in 2007, and it is estimated that the rate in 2016 has improved to 0.68. In the above-mentioned project, 1,700km of water distribution pipes is planned to be installed in total. So far installation work of 1,560 km has been completed, of which 1,470km has already been in service. As for private connections, the project plans to connect to 80,000 households, of which 54,000 households have been completed as mentioned in the Table below. Table 6.1: Number of New Connections in Communes Commune Number of new connections Arafat 13,000 Riyadh 5,200 Teyarett 11,000 Dar Naim 9,800 Ksar 5,500 Tevrag Zeina 3,000 Sebkha 2,700 El Mina 3,800 Total 54,000 Currently, water distribution reservoirs that supply water to Nouakchott city are 3 ground type reservoirs of 5,000m3 capacity and 1 water tower of 1,000m3 in the city center (Zone Château d'Eau), a ground type reservoirs of 5,000m3 in Toujounine Commune and an elevated tank of 1,000m3 in the second water treatment plant of Aftout project, and the total storage capacity is 22,000m3. In addition to the above-mentioned existing reservoirs, construction work of a water distribution facility consisting of two reservoirs of 5,000m3 (5,000m3×2) and a pumping station supplying water to Sebkha and El Mina Communes located in the western part of Nouakchott city and a reservoir of 5,000m3 in the existing pumping station supplying water to Toujouniue Commune is in progress. A plan to construct two new pumping stations in Zone Château d'Eau to supply water to the central urban district of the city and to the three communes in the northern part of the city (Dar Naim, Teyarett, and Tevrag Zeina) is on-going. When the above-mentioned construction work will be completed, the capacity of the water reservoir is expanded to 37,000m3. Also, due to the construction of the pumping stations and the improvement of the water distribution network, the water supply in the surrounding area of Nouakchott city, which is now poor water supply area, will be greatly improved. Flow diagram of the Aflout project and the project for improving water distribution network is illustrated in Figure. 6.1. (6) Problems of the existing system Currently, water supply in Nouakchott city has been greatly improved due to the commencement of water service of Aflout project, but improvement of water distribution network cannot keep up with the expansion of urban area. For this reason, non-water supply areas are expanded in the city and residents 258 Nouakchott City Urban Master Plan Development Project Final Report in the areas are obliged to rely on buying water from public water station, water tankers and water supply cart of water venders. In order to resolve the non-water supply areas, it is necessary to implement the on-going project for improving the water distribution system without delay. In the future, as the water supply amount of the city increases with the progress of improving the water distribution network, it becomes gradually difficult to properly distribute water at the current capacity of distribution reservoir (22,000m3), so keeping pace with the improvement of the water distribution network, expansion of the capacity of the distribution reservoir also needs to be implemented. 6.1.2 Development issues and directions (1) Secure water source As mentioned above, the water supply in Nouakchott city has the Iddini system with groundwater source and the Aflout system with the surface water source from the Senegal river The Iddini system supplied water of 23.72 million tons per year (= 65,000m3/day) before the commencement of water service of the Aflout system, which is considered to be the maximum capacity of the Iddini system. On the other hand, the maximum capability of the Aflout system is at present 150,000m3/day and it is supplying water from 60,000m3/day to 85,000m3/day. The system is able to expand water supply capacity up to 226,000m3/day, and in order to expand the capacity, it is necessary to construct a booster pump at the midpoint of the raw water transmission pipe (diameter 1,400mm×170km) between the first water treatment plant and the second water treatment plant of the system. Construction work of the booster pump is in progress, and it is in the stage of test operation. In developing the water supply facilities, it is necessary to expand the capacity of water source at the appropriate time based on the capacities of the above-mentioned groundwater source and surface water source and increasing water demand in future. (2) Increase of average specific water consumption As a method of water supply in Nouakchott city, there is a private connection that is connected to the distribution network of SNDE, and a method of supplying water with a water tanker or a cart in the area where the water distribution network is not well developed. In addition, there are "full plumbing" (indoor piping) and "yard tap" (using external faucet) for private connections. According to the estimation by SNDE, after inaugurating water service of the Aftout project in November 2010, the water supply by cart decreased from 61.5% to 50.3%.