The climate is changing worldwide. For the northern hemisphere there are distinct challenges related to climate change. It is expected that temperature on a general basis will increase within the next 100 years, and that the increase will be most severe during winter months. The literature shows a correlation between temperature and failures. This correlation is most evident for smaller grey cast iron pipes, and for pipes which is constructed in trenches vulnerable to frost heave. A comprehensive amount of failure data (over 25,000 failures) has been gathered from Norwegian cities in order to quantify the correlation between temperatures and failure rates. The analysis supports the findings in the literature, by establishing a statistical significant correlation, which states that failure rates increase with falling temperatures. At the same time, the expected increase in future temperatures has been used to analyze the impact on failure rates within 2070. The results show that the increasing temperatures will have a positive effect on failure rates. It can be expected that failure rates will be reduced by 2.7% to 7.2% within 2070, depending on the climate scenario.

Managing the urban drinking water system in the long term in order to maintain system performance can be challenging due to the difficulty of modelling future deterioration of the networks. This paper establishes a methodology for cohort survival models where historical (empirical) data on decommissioning ages of pipes are used to calibrate survival functions of pipe cohorts according to service level targets. The benefit of the approach is that remaining useful life of pipes, future renewal rates and investment needs can be governed by a required level of service in the network. A case study shows how the methodology can be applied to a cohort of drinking water pipes to create a ‘calibration curve’, which is a survival function calibrated with empirical data.

It is generally difficult to assess the performance of an infrastructure with a substantially longer life span than economic models can handle, and the life cycle concepts in urban water systems are normally limited to single-asset projects. In order to explore the long-term impact of urban water infrastructure rehabilitation strategies, a life cycle approach for survival functions is suggested. A life cycle factor based on survival functions is introduced, which is a measuring value of the total expected service life of all pipes within a group of pipes. Another factor, termed the sustainability factor, is based on the relationship between the life cycle factor and a rehabilitation reference method, which makes it possible to correct the long-term performance of rehabilitation methods based on their expected service life provision. A case study presents the implications for investments in infrastructure rehabilitation when applying the sustainability factor in long-term planning, and shows the importance of considering the service life of rehabilitation methods when planning renewal interventions that minimize costs over their life cycles.

Water utilities are facing the challenging problem of planning rehabilitation and renewal of their urban water systems for an uncertain future, which will be affected by climate change, demographic changes and extensive changes in the way the public perceives the water services. For the purpose of envisioning the future, the multiple scenario approach is presented, and its benefits and drawbacks are discussed in relation to other futures forecasting methods. The paper guides the reader on how to build scenarios that represent plausible futures for renewal planning of urban water and wastewater networks. For this purpose, a table is produced that gives an overview of relevant scenarios and their potential consequences. In the end, a case study from a Norwegian perspective is presented that gives the reader an overview of the process of building scenarios based on both qualitative and quantitative approaches.

Nature-based solutions (NBSs) are widely implemented for stormwater management; as such they have become important assets that require proper asset management at different stages of their service life. Hence, there is a need for systematic documentation of the applied NBS in accordance with the principles of infrastructure asset management and in combination with a set of requirements in the newly adopted National Standard NS3456:2022 in Norway. A framework for the documentation of NBSs was developed based on a systematic literature study, the experience gained from operating NBS pilots, and the interaction with stakeholders in a research centre, Klima 2050. The framework proposed a set of specific information in the form of a data structure covering a set of categories that presents information gathered during the planning, design, operation, and maintenance phases of the NBS. Both technical and sociotechnical aspects were included in the data structure. The data structure can be tailor-made depending on the type of NBS applied. The data structure was applied in documenting the NBS pilots of the research centre to demonstrate the framework's ability to help ensure a smooth flow of information from the actors involved in the planning, constructing, and operating of the NBS.