This study describes field investigations designed to compare the infiltration capacities of 55 permeable pavement systems installed in the Netherlands and in Australia. The ages of the pavements varied from 1 to 12 years. Using infiltrometer testing, the performance of the pavements has been compared in terms of their ability to infiltrate a three month average recurrence interval storm event in the case of the Australian pavements or the minimum specification for European infiltration capacities of 97.2 mm/h for the Dutch pavements. Many of the tested pavements broadly follow a hypothetical decay curve of infiltration rate with age of pavement. However, these are clustered into two distinct groups (Dutch and Australian) with the older Australian pavements appearing to maintain higher infiltration rates relative to their age. The study has shown that the performance of the clogged permeable pavement systems was still generally acceptable, even after many years in service.

Permeable pavements are a type of sustainable urban drainage system (SUDS) technique that are used around the world to infiltrate and treat urban stormwater runoff and to minimize runoff volumes. Urban stormwater runoff contains significant concentrations of suspended sediments that can cause clogging and reduce the infiltration capacity and effectiveness of permeable pavements. It is important for stormwater managers to be able to determine when the level of clogging has reached an unacceptable level, so that they can schedule maintenance or replacement activities as required. Newly-installed permeable pavements in the Netherlands must demonstrate a minimum infiltration capacity of 194 mm/h (540 l/s/ha). Other commonly used permeable pavement guidelines in the Netherlands recommend that maintenance is undertaken on permeable pavements when the infiltration falls below 0.50 m/d (20.8 mm/h). This study used a newly-developed, full-scale infiltration test procedure to evaluate the infiltration performance of eight permeable pavements in

The European Union Water Framework Directive (WFD) encourages water managers to implement active stakeholder involvement to achieve sustainable water management. However, the WFD does not describe in detail how member states should operationalize participation. The need for local experience and local understanding of collaborative governance (co-governance) processes remains. The WaterCoG project evaluated 11 local pilot schemes. Building on the participatory, qualitative evaluation of pilot schemes from Sweden, United Kingdom, Denmark, The Netherlands, and Germany, the authors take a closer look at how co-governance can improve water governance, how water managers can make best use of tools and knowledge, and how they can improve process designs. The results reflect how social learning and successful co-governance are linked. Social learning as a shared understanding of complex ecosystem and water-management issues can be supported with active stakeholder involvement and citizen science. As such, in co-governance processes, stakeholders need technical access to data and knowledge and a shared process memory. This enables them to develop a shared understanding and facilitates bringing together competing interests and finding new solutions. Participatory tools became part of successful processes by building trust and knowledge based on commitment. However, proficient process design and facilitation make these tools more effective.