Current urban water systems are criticized by many organizations, stakeholders and citizens. Negative aspects of the current urban water system include: effects of urban runoff, the lack of recycling of nutrients, the use of purified water to transport waste, land subsidence, high investments and maintenance costs, and the lack of flexibility to cope with future challenges. Cities show parasitic behavior. They extract all required resources from the surrounding area and after using them, discharge the pollutants to this area. Cities hardly use internal resources of water, energy and nutrients and require more and more space.

Urban water systems consist of five interrelated types of water in urban areas: groundwater, surface water, stormwater, drinking water and wastewater. Urban water management is defined as the management of quantity and quality of stormwater, groundwater and surface water in urban areas. Innovations are defined as technologies that enable using the urban water system for new functions. Urban water systems have two sources of water: precipitation and external drinking water supply through pipes.

Rainwater is converted to stormwater when it falls on paved and unpaved surfaces. During heavy rainstorms, the capacity of the sewer system is not sufficient to transport all runoff. In that case, combined sewer overflows (CSO’s) take place. This leads to the emission of diluted wastewater and sewage sludge into the urban surface water. Industrialization and rapid urbanization also caused severe public health problems and water shortages.

Societal concerns about public health, criticism from hygienic doctors and engineers, rapid urbanization, changes in legislation and normative and behavioral changes contributed to the diffusion of sewer systems.

There are many drivers for the urban water system to change. Ashley et al. (2007) mention three most important drivers for sewer systems: (1) environmental legislation, public attitudes and expectations, (2) land use and urbanization and (3) energy and resource stress. Other drivers are: privatized ownership of water infrastructure, new pollutants risks, new technologies, demographic developments, and the lack of sustainability of current systems. Climate change is more and more mentioned as a major driver for changing urban water

systems.  Urban water systems should aim to reduce the vulnerability of peoples and ecosystems.

RESPONSIBILITY:

Phase One: Urban Water Management Innovations to Reduce Vulnerability

1. Overview of schematization of the urban water system in Accra                                                                    

2. Examine stormwater management and multi-source water supply in Accra.

3. Using local water resources for the decentralized production of drinking water in Accra.

4. Using the surface water for urbanization /floating.

                                                                                    

 

      

Phase 2: Mainstreaming of Urban Water Management Innovations

 

1. Linking water management and urban renewal     

                   

2. Receptivity to transformative change in urban water management sector.

3. Perspectives on innovation: a survey of the urban water sector.

4. Interventions for mainstreaming urban water management innovations to reduce vulnerability.