This special edition of the Urban Water Journal consists of papers from selected contributors on urban drainage in developing countries. The editors hope that the selected papers reflect the situations, issues and solutions to some of the key urban drainage problems.
In the first paper, Parkinson et al. describe urban drainage as a component of urban upgrading and discuss issues related to the integration of drainage systems serving informal settlements into citywide stormwater management systems. Experiences from urban upgrading schemes in different parts of the world are used to highlight innovative approaches towards planning and design as well as illustrating examples of potential problems that may be encountered during project implementation and subsequent operation.
Armitage discusses how urban litter (alternatively called trash, debris, flotsam, jetsam, floatables, gross pollutants, rubbish or solid waste) represent a major problem in South Africa. His paper summarises the results of research into the control of urban litter in urban catchments, and the cost-effective removal of the portion that makes its way into separated stormwater drainage systems.
Marques describes an investigation of pollutants in stormwater runoff from a landfill site according to different areas for sorting, recycling, storage and treatment of municipal and industrial waste. In this work, field measurements and calculations based on a historical time series of precipitation were used to estimate stormwater volumes and pollutant loads generated from asphalt, gravel and steep slopes of landfill cells. The study suggests that the stormwater runoff from waste management sites is likely to be an important source of pollutants, particularly with respect to chemical oxygen demand and nutrients such as phosphorus and nitrogen, in comparison with stormwater runoff from other land uses such as roads, and urban residential and industrial areas.
The paper prepared by Gupta describes lessons learned on urban flood resilience planning and management from a case of study in Mumbai, India. It refers to the rainfall event that occurred on 26 July 2005 which was measured to be 994 mm over a period of 24 h. At least 419 people (and 16,000 cattle) were killed due to the ensuing flash floods and landslides, and another 216 deaths were due to flood-related illnesses. The paper describes Mumbai's drainage system, the details of the flooding, and the measures being taken by the city to mitigate such floods in the future. The Mumbai experience can be very useful for planning response strategies for other large cities to cope with similar events in the future.
The paper written by Nascimento et al. discusses the assessment of damages caused by floods in the Brazilian context. The paper describes a methodology to develop and apply flood damage curves (FDC) in Brazil, using a case study from the city of Itajubá, Minas Gerais. The methodology and results illustrate the possibilities of using this kind of flood damage appraisal method in Brazil on the basis of information and data usually available in this country. The application of FDC for the evaluation of flood control alternatives in the future could certainly serve as an important aid for the decision making process.
Finally, Vojinovic and van Teeffelen describe a new integrated stormwater management approach oriented towards small islands in tropical climates which tend to suffer regularly from flash floods. The approach outlined here draws on the work carried out in the Caribbean where the most common and the widely experienced hazard events are tropical cyclones and accompanying storm surges, flash floods and landslides. Such events have caused serious damage to the drainage systems, roads, properties, and the receiving environment, and even the loss of human lives. The principle of the integration of different aspects of the stormwater management process is highlighted in the paper. Regardless of whether this principle is applied between different sources of data, or data and models (i.e., data assimilation), or structural and non-structural measures, or different kinds of models aimed to help us understand diverse flood-related processes, or various elements of real-time flood warning systems, or the views of all relevant parties – the stakeholders – within the decision making process, it is inherent to the solution of stormwater-related problems. Furthermore, the paper proposes an approach where digital flood GIS maps based on results generated by numerical models are transformed into cell phone messages using appropriate broadcasting technologies (GSM and UMTS) and directed to a specific geographical area. The application of such a non-structural measure appears to be crucial for those regions which suffer from tropical storms and hurricanes and which do not have sufficient resources for protection.