|Managing Natural Disasters and the Environment (World Bank, 1991, 232 p.)|
Alcira Kreimer and Martha Preece
The Taiz Flood Disaster Prevention and Municipal Development Project represents an important step forward in urban development. For the first time, environmental protection and prevention have taken precedence over other types of investment - in a project that aims, among other things, to improve drainage systems in one of the Yemen Arab Republics major cities. One aim of the project is to prevent recurrent floods from disrupting the citys economic activity, damaging roads and other infrastructure, and plugging up sewers with sediment and refuse, causing water contaminated by garbage and human waste to overflow on the streets. Another aim is to organize a unit within the Ministry of Municipalities and Housing to coordinate that ministrys activities with those of the National Committee for Natural Disaster Mitigation and Emergency Relief. What began as an effort to upgrade urban services and strengthen government institutions developed into an integrated approach to urban development. It incorporated the urgent need to resolve an environmental crisis into longer-term plans to reduce the citys vulnerability to natural disasters and improve its ability to service a rapidly expanding population.
Taiz, the second largest city in the Yemen Arab Republic and its principal trading and agricultural processing center, suffers many of the problems of rapid urban population growth. The population of 150,000 (about 12 percent of YARs total urban population) is growing more than 15 percent a year and has more than doubled in the past five years. A survey undertaken during preparation of an International Development Association (IDA) project revealed that about 28 percent of the homes in the project area and nearly 280 shops are flooded every year, and 32 percent of the homes are flooded every 10 years.
The last severe flood occurred in March 1982, when three days of consecutive rain caused widespread damage. Events of this magnitude occur once every 20 years or so, but floods that cause moderate property damage and disrupt traffic for two to three hours occur five to 10 times a year. With moderate flooding, sediment accumulates up to one meter deep at major intersections. Streets erode substantially and in many places underground utilities (water, sewerage, and electricity and telephone lines) are exposed to pedestrian and vehicular traffic. About 15 percent of the 5,134 households in the project area, or 770 households, live below the poverty threshold, and an equal number of families live within 10 percent of it. These homes and small-scale businesses are generally hurt most by the floods. The annual direct loss from floods is about YR 29.24 million (US$2.7 million), mostly in property damage to and missing stock from households and shops.
Flooding directly affects the Old Town and the areas immediately north of it, but they also suffer the indirect costs of production losses caused mostly by the destruction of physical infrastructure (such as roads, canals, drainage, and electric power networks). This important market and commercial area provides jobs for people residing in other neighborhoods.
Not only does the flooding of roads and the deposit of sediment, boulders, and refuse disrupt traffic and business activities, but it is costly to clean up and repair damaged infrastructure. Cleanup and road reconstruction cost an average YR 1.8 million a year (US$170,000) for the project area, which is grossly insufficient to restore the street pavement, given the budget constraints of the Taiz Branch Office (TBO).
The citys vulnerability to disasters
Three factors make the Taiz area vulnerable to natural disasters: (1) environmental degradation, caused mostly by the unplanned expansion of human settlements; (2) poorly maintained infrastructure and services inadequate to cope with increasing demand; and (3) the managerial and financial weakness of regulatory and policy institutions, which result in inadequate planning, programming, budgeting, and technical staff.
Rapid growth and scarce resources have made it difficult for national and local institutions to deal with the pressures that urban development exerts on the environment. High-income housing and road construction are extending onto steep hills, destabilizing the slopes and increasing soil erosion. Depleted of their weight-bearing capacity, these unstable lands are unsuitable for residential development. Moreover, wadis (drainage courses) are being used as roads and houses have been built on the floodplains, so there is little protection against floods. Residential neighborhoods have sprung up over the original drainage channels, which have been transformed into main streets of residential areas. Erosion, degradation of the land, and reduction of the soils absorptive capacity have weakened the regions resistance to catastrophic flooding.
Attempts have been made to drain rainwaters from some major streets by providing drainage channels, but these measures are insufficient, and authorities often use sanitary sewers to discharge water runoff. This increases the health hazards caused by floods, as sewers plug up with sediment and refuse, causing water contaminated by garbage and human waste to overflow on the streets. The accumulation of urban wastes outstrips the citys ability to collect and dispose of them.
Rapid urban population growth in the 1970s and early 1980s brought major changes in urban land use and the uncontrolled, haphazard, inefficient spread of informal housing in urban areas. Despite the governments struggle to cope with escalating demand for urban services, their provision lagged behind demand. Weak local institutions were not prepared to handle development pressures. And recurrent floods in Old Taiz hampered every effort to provide municipal infrastructure. Contributing to the deficiencies in urban service have been (a) the absence of urban land management policies and a formal land registration system, (b) the failure to fully recover the cost of urban services, which eroded the governments ability to finance such services, and (c) building standards that are unrealistic because much of the population cannot afford them. YAR has struggled to establish the basic institutional framework for urban development and to keep ahead of the backlog in urban services, but it has been handicapped by inadequate funds and a lack of qualified technical, administrative, and managerial manpower.
Until 1979, government intervention in the urban sector was ad hoc, with different agencies implementing their own projects independently. In 1976, the Ministry of Public Works (MOW) initiated the preparation of master plans for the YARs five main cities. Those plans were an appropriate framework for directing urban growth, but they proposed standards that exceeded the urban agencies financial and implementation capabilities.
The main problems are accelerated urban growth, inadequate basic infrastructure, and weak managerial and financial capabilities in the urban agencies. The governments strategy in the urban sector is to provide essential municipal infrastructure and to strengthen central and local institutions.
IDA activities in the urban sector
Aware of the countrys difficult economic situation, the mounting pressure of urban problems, and the poor coordination among ministries and agencies responsible for planning and implementing investment projects, IDAs short-term strategy in the urban sector is a well-targeted project work addressing central and local institutional and structural weaknesses (urban infrastructure maintenance, municipal resource mobilization, land registration, and housing finance) requiring a minimum, directly recoverable investment and making maximum use of existing resources. By building on the achievements of the first two ongoing urban projects, this project aims to prepare the groundwork for broader policy-oriented sectoral involvement and to set the stage for long-term urban development by creating a viable administrative system that will delegate more responsibility to the municipalities while maximizing private initiative.
The Taiz project grew out of discussions between the director of the Taiz Branch Office of MMH and an IDA mission carrying out an urban sector study in YAR, in February 1984. Initially, the project was to address problems upgrading the Old Town of Taiz, to develop serviced land suitable for low-cost housing, and to improve urban transport in Sanaa. The project was to include funding for a major study of flood control, with physical implementation deferred until a later phase. But a feasibility study carried out under the Second Urban Development Project (Credit 1441-YAR), completed in 1988, concluded that flood control should take priority over any other type of improvement - as failure to control the floodwaters from the main drainage system could wipe out any investments in urban upgrading.
Because of YARs economic problems, it was agreed to divide the project into freestanding phases of construction, and limit project implementation to the most essential flood control structures. Urban upgrading components were to be postponed until after the flood control works were completed.
The objectives of the Bank-financed project were to address the problem of flooding in the city of Taiz, to finance the implementation of cost-recoverable infrastructure investments, and to correct structural weaknesses in the central and local government through technical assistance and training and policy reform. The project covers the Old City (Medina), an area of about 100 hectares in the valley and foothills of Jebel Sabir, and the adjacent area to the north (about 80 hectares). Three drainage courses pass through this area. Surface materials are alluvium (sand and gravel) to varying depths in the valley and rocky outcrops in the south where groundlevels rise. The main residential area of multistory houses was built to the south on steep slopes. The old marketplace occupies the flatter alluvial section at the northern edge of the Old City.
Estimated cost for the project is US$22.25 million equivalent (YR 267 million), of which US$15 million equivalent represents the foreign cost component (or about 67 percent of total project costs). IDA will finance all of the projects foreign exchange, and the government will finance the local cost (US$7.25 million equivalent).
The Ministry of Municipalities of Housing (now the Ministry of Housing and Urban Planning) is responsible for the physical planning and administration of the five main cities and of the secondary towns. The Taiz Branch Office is the ministrys local operating arm for both the city of Taiz and the surrounding smaller cities and rural areas in the Taiz Governorate.
The ministrys core unit, the Physical Planning Department (PPD), prepares master plans and issues buildings permits. PPDs work is hampered by a shortage of trained personnel in middle-level positions, lack of reliable physical and socioeconomic data, financial constraints, and no overall strategy for urban planning and management. The department has a physical plan but it does not take an integrated approach to preventing and mitigating natural disasters through appropriate urban development and spatial planning.
The Urban Development and Housing Department (UDHD) is in charge of formulating and implementing objectives and strategies for national urbanization and housing programs. UDHD was responsible for the execution of the two previous IDA-financed projects and will be the implementing agency on the Taiz project. Its operational and policymaking capabilities must be strengthened, especially at the municipal level. Its technical and managerial staff is its main weakness; it needs training to improve its engineering and planning capabilities and to strengthen its delivery of urban services.
The National Water and Sewerage Authority (NWSA) provides water and sewerage, the Yemen General Electricity Corporation (YGEC) provides power, and the Highway Authority is in charge of interurban road construction and maintenance. YAR also has institutions for land survey and registration, health and education services, public transport, cooperatives and popular participation, and housing finance (the Housing Credit Bank). All capital projects and maintenance activities are centrally prepared and approved.
During project preparation several design standards and drainage routes were considered. The basic design for all of them incorporated drainage channels and box culverts through the built-up sections of the city, sediment and boulder traps upstream, the channelization of secondary wadis originating from Cairo Hill (south of the project area), and soil conservation measures.
Two alternative flow parameters were considered for the design of hydraulic structures. The minimum acceptable protection was for the type of flood that occurs only once every five years (a 1: 5 year flood), and the economically acceptable maximum protection was for a 20-year flood. The narrowness of the streets limited the design capacity that could be economically provided. It was concluded that a hydraulic system designed to carry all of the flows of a 20-year flood and about 90 percent of a 50-year flood was the least-cost alternative that would yield the maximum possible protection against any reasonable risk to human life.
Several drainage routing alternatives were studied to determine the least-cost solution that yielded maximum benefits and adequately protected life and property. Economic costs and the ability to preserve historical buildings were among determining factors in the selection of flood control designs for the three main local wadis (Seena, Al Nassar, and Madam).
The project provides
· The flood control structures needed - open channels, box culverts, and sediment and boulder traps - to protect the parts of the city most affected by floods (Wadi Seena, Al Nassar, Madam, Al Kamet).
· The restoration of street pavements, the terracing of unstable slopes, and surface drainage footpaths in narrow streets (to control erosion).
· The purchase of maintenance equipment for roads and flood control works.
· Technical assistance for strengthening the Ministry of Municipalities and Housing and its main branch offices.
· Technical assistance for project construction management.
· The introduction of a new municipal resource mobilization policy initiated under an ongoing urban project.
· The implementation of project cost recovery.
· The preparation of a future urban development project.
· Staff training for MMH and its main branch office.
Because of financial constraints, the project was to be implemented in several phases, with essential flood control works provided first to protect other investments, including the urban upgrading that would enhance land development in areas bordering the wadis. Further urban upgrading will be considered when it becomes possible to mobilize local funds.
Disaster prevention a development priority
The Taiz project represents significant progress in IDAs approach to urban development. For the first time, environmental protection and prevention took priority over any other type of investment program in YAR and environmental considerations are integrated into the planning, management, and coordination of urban investments. Implicit in project design is the recognition that poor planning and inadequate urban infrastructure result in degradation that puts people at risk from natural hazards.
The project aims to improve the human and natural environments by preventing sewage overflows and by minimizing hazards now posed by domestic refuse, sand, gravel, and boulder that floodwaters deposit on main streets.
In a remarkable effort to incorporate disaster prevention and mitigation strategies into national and municipal development planning, the project contemplates improving the Physical Planning Departments ability to integrate natural disaster mitigation and warning systems into urban development of the major cities. It also contemplates strengthening MMH and its municipal branch offices to improve service and operating efficiency and to help MMH establish and organize a Disaster Preparedness and Relief Unit to coordinate the ministrys activities with those of the National Committee for Natural Disaster Mitigation and Emergency Relief.