Improving landscape resilience by integrating measures to adapt and mitigate hydrological extremes

It is critically important to protect society from the effects of floods and droughts, which will occur more frequently in future due to climate change. LandEX aims to improve landscape resilience to hydroclimatic extremes – both floods and droughts – by spatially optimising a suite of adaptation measures in the landscape. Knowledge gaps addressed by LandEX include:I. How different (Nature Based Solution; NBS) measures can increase water retention in the landscape and, thus, mitigate floods and droughts at the same time;II. Howtheirspatiallocationdeterminestheireffectivenessatthelandscape level, andIII. Potential synergies between a network of different measures distributed throughout the landscape to mitigate both floods and droughts.LandEX uses the concept of hydrological connectivity to design spatially-explicit adaptation scenarios which retain water from wet periods to be available during dry periods. To quantify scenario effectiveness at the regional scale, LandEX uses connectivity-based spatially distributed hydrological modelling. This approach is tested in 5 study areas in northern and southern Europe. LandEX works closely with local and regional stakeholders, as it is crucial to co-design such adaptation scenarios to ensure their feasibility and adoption and to incor- porate them into regional spatial planning.LandEX aims to achieve the following objectives, addressed in specific Work Packages (WP):• WP1:Investigateineachstudyarea(i)thecurrenthotspotsforfloodand drought occurrence; (ii) how existing flood and drought mitigation measures perform and/or why they are not effective, both technically and socioecono- mically; and (ii) potential synergies of (NBS) measures to mitigate both floods and droughts, using the concept of water retention landscapes.• WP2:Co-designspatialadaptationscenariosoffeasibleandpotentially effective suites of measures in the landscape, in close collaboration with local stakeholders.• WP3:Quantifytheeffectivenessoftheadaptationscenarios(fromWP2)on floods and droughts using spatially explicit hydrological models.• WP4:Developatooltosupportmanagersinoptimisinglandscaperesilience to hydroclimatic extremes and to visualise scenario outcomes through an online map interface.• WP5:Stimulateco-learningbetweenthe5studyareasbyenablingexchange of experiences with different sets of innovative adaptation measures.While building on previous experience within the consortium (e.g. modelling, stakeholder relations), LandEX contributes to important innovation: we expli- citly seek measures that can work for both floods and droughts in a synergistic way, so that their combined effect is more than the sum of their parts. This is highly needed, as only a limited number of measures can be implemented inan area. In addition, our approach focuses on using NBS to affect hydrological connectivity: i.e. measures that slow the flow of water in the landscape can retain water from wet periods to be available during dry periods. Quantifying the effectiveness of multiple measures is not often done in a spatially explicit way, while by doing so, their (spatial) interactions and feedbacks are takeninto account, which is needed to detect synergies between different types of measures at various locations in the landscape. We use spatially-explicit hydro- logical models to assess the effectiveness of multiple configuration of measures. Finally, the co-creation of the spatial adaptation scenarios by groups of multiple stakeholders incorporates the socio-economic feasibility of the measures and helps overcome institutional barriers.LandEX consortium partners have great experience with floods and droughts, mitigation measures, including NBS, hydrological modelling and stakeholders participation in projects. In addition, consortium partners have collaborated in earlier and ongoing projects.