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In rapidly urbanizing catchments, increase in stormwater runoff may cause serious erosion and frequent floods if stormwater management systems are improper and dysfunctional. Through GIS-based modelling, field investigations, resident’s questionnaire survey, and interviews with officials, the study set out to assesses the coverage and efficiency of drainage infrastructure in Mbezi River catchment basin in Dar es Salaam, Tanzania. Between 2003 and 2016, the catchment imperviousness increased by 41%, causing flood incidents, massive erosion, and numerous pollution sources. Residents strive to address stormwater hazards using terraces, hedges, and physical barriers; however, the problems persist, indicating lack of coordination and poor causality understanding between land-use changes and catchment impacts. Small-scale stormwater harvesting was exercised by 75% of the households, pointing to water supply challenges. Municipal stormwater management efforts was limited to roadside drains covering 17% of road lengths in the catchment, and 65% of those did not meet their design standards. Interviews with officials revealed a need for improved co-understanding and collaborative initiatives to bolster integrated water management. The study suggests a need to adopt a new urban stormwater management paradigm, appropriate for both residents and authorities. Without this new discourse, the urbanization led stormwater increase might jeopardize the liveability of the entire catchment.

he white paper presents the various possibilities of using rainwater as a resource as opposed to considering it as something that simply needs to be hidden in sewers. The aim of using rainwater as a resource is partly to reduce the risk of flooding by optimising the rainwater management and partly to contribute to creating more green and liveable cities.

Analyse viser, at omkring 80 miljøfremmede stoffer regelmæssigt findes i afstrømmende regnvand.

The article presents a study which compares the three saturated hydraulic conductivity (Ksat) measuring methods such as double ring infiltrometer, Guelph permeameter, and infiltration tests in small excavation. The study performs infiltration tests in an area featuring Danish clayey till. Result shows that the Guelph permeameter and double ring infiltrometer havlower average values than infiltration holes method.

How can we motivate urban planners, water utilities and house owners to collaborate about sustainable urban water projects and to aim for solutions that go beyond the narrow perspective of individual stakeholder interests? A concept for framing a multidisciplinary learning process is developed in the research project: Black blue green: Integrated infrastructure planning as key to sustainable urban water systems, with the acronym 2BG. The concept addresses the need for local authorities to develop competences for adopting an integrated approach including different internal departments. The concept is referred to as ‘the 2BG platform concept’. The 2BG platform concept as been tested three times and proves to a step in the intended directions of developing organisational competences for an integrated approach in sustainable urban water projects. Primarily because it invites urban planners, road and park managers, and sewage managers to a dialogue about sustainable urban water projects while exploring cases of new design solutions; secondly because it facilitates an appreciative communication between “softer” and “harder” disciplines, and thirdly because it promotes multidisciplinary thinking during the early stages of an urban water project. To realise new sustainable urban water designs a project team will need to engage and get acceptance from internal and external stakeholders, and this calls for communication and social skills rather than technical skills. The paper identifies potential stakeholders that can support or potentially stop urban water projects. Competences of network governance represent a need to break out of the conventional urban water design and to develop new designs where storm water is handled visible to citizens. The platform concept is in a Danish context a milestone in capacity building for integrating urban planning with water management and management of parks and roads, and might inspire others to rethink planning processes and to build organisational competences to innovate urban water management for the benefit of present and future citizens.