Part B: Research description 1. What are the focus and added value of this research from both an academic and practical perspective?

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1 Part A: Formal information Programme: Rivercare Project: H: Self-supporting Hydrosystems & Valorisation Project leader: Toine Smits Subproject: H1: Optimizing river management Supervisors: Maarten Kleinhans, Hans Middelkoop Participant: Menno Straatsma, Post doc Duration: Augus 2014 August 2017 Part B: Research description 1. What are the focus and added value of this research from both an academic and practical perspective? The river system consists of three interacting components, which can be characterized as the hydrosystem, the ecosystem, and the socio-economic system. In time, the autonomous development of the river system is combined with additional pressures from climate change and socio-economic developments, which necessitate landscaping measures in lowland fluvial areas. Which measures to take depends, amongst others, on the goals of the intervention, the perspective of the decision maker, and the societal preparedness for change. Multiple components of river management have been studied by Baptist et al. (2005) using a 1D hydrodynamic model for cyclic floodplain rejuvenation, and by Straatsma et al. (2013) using a 2D representation of the fluvial system. Coupling of decision making under uncertainty has been modeled by Haasnoot et al. (2012) using a hypothetical river system represented in a 1D model and a set of transfer functions that determine the effects of the selected measures. In river management practice, interactive tools (map table, blokkendoos ) are being used to quickly assess the hydrological effects of landscaping measures to create support for interventions. What is currently not available is a 2D integrated model of the river system that can cope with hydromorphodynamic processes as well as ecological processes to support an optimal choice of landscaping measures. From a practical perspective, additional value will be created by a fast and complete overview of the possible layouts of the fluvial landscape, which can inform and direct decision making processes. 2. What are the research questions and aim of this research? Research questions: What is the Pareto front of sets of landscaping measures with respect to hydromorphological, and ecological functioning? How does the temporal horizon affect the choice for landscaping measures? What is the cost-benefit ratio for these sets of measures? Objective: Determine the an optimal set of river landscaping measures and evaluate the evolution over time to support decision making.

2 Methodological steps: Create an inventory of user requirements for decision support. Set up a modular two-dimensional metamodel that enables fast evaluation of multiple landscaping measures. Determine Pareto fronts of landscaping measures based on different sets of criteria in the hydro- and ecosystem 3. What is the methodological approach of this research? To reach the aims, the following steps will be carried out. Firstly, an inventory of the user requirements with respect to decision support, model integration and optimization will be carried out. Secondly, a model chain will be set up that enables the fast evaluation of different landscaping measeres using a Monte Carlo(MC) scheme. The preliminary flow chart (Figure 1) shows the input of this scheme, which consist of a flow duration curve and hydrodynamic model(hydrodynamic system); ecotopes and their succession stages in the ecosystem; landscaping preferences and government in the socio-economic system. The main drivers of this system are climate change, which is represented by the flow duration curve, and socio-economic change that drives landscaping. Within the Monte Carlo loop, a landscape is generated, and evaluated with respect to three domains in river management. The fluvial landscapes are generated using riverscape, a model that will be developed for this project. It consists of a semi- automatic parameterization of landscaping measures determining the position and dimensions of measures such as side channels, floodplain lowering, dike repositioning, dredging, nature development, and removal of minor embankments. RiverScape produces an updated parametization of the hydrodynamic model (WAQUA, or Delft3D), and ecotopes. A model integration will be carried out to combine hydromorphodynamics (WAQUA/Delft3D/D-Flow) with biodiversity (BIOSAFE), and ecosystem services. Ecosystem services are not yet part of an existing model and will be developed based on the output of other RiverCare projects (E2, H2). These three models produce relevant hydrodynamic, and ecological output. The outcome of the MC analysis consists of an overview of each realization, and intercomparison of the different realizations, and a spatial overview of all aspects as a function of position along the river. Output will be plotted in different feature spaces with axes representing costs, hydrological functioning (low flow, peak water levels, flood risk), or ecological functioning (ecosystem services, biodiversity values, food web quality). Optimal realisations of the landscape form a Pareto front in these feature spaces (Figure 2). The Pareto front indicates the combinations of minimum cost, and minimum flood risk. Many other feasible realisations exist, but they are suboptimal. Points below the Pareto front are infeasible, with the utopic point (no flood risk at no cost) as the extreme. The temporal dimension is added by implementing time-varying roughness based on ecotope succession, and silting up of side channels. The effects of the changes over time can be plotted in the same feature space. Figure 2b shows a single Pareto point with its changes over time in terms of cost and flood risk under two management strategies (T1 = 5y, T2 = 15y, T3 = 50y). Management strategy 2, in orange, has higher cost over time, and less increase in flood risk.

3 4. What are possible links with other Rivercare projects and research? Is this research depending on results from or cooperation with other projects? This project is potentially linked to many other projects within RiverCare, see the table below with possible interactions with other subprojects. However, there is not necessarily a need for the output of other projects as initial assumptions can easily replace more detailed modules later on that integrate more process-based knowledge. The most important links are printed in bold. Table 1. Possible links of H1 with other RiverCare projects. RiverCare projects A Optimizing longitudinal training dam (LTD) design A1 Hydraulics of LTDs (PhD) A2 Ecology of LTDs (PhD) B Side channels and erosion of natural banks B1 Side channels B2 Natural banks (PhD) C Regional River systems D. Sediment nourishment and floodplain monitoring D1 Nourishment D2 Dredging D3 Floodplain monitoring E Ecosystem services and floodplain rehabilitation E1 Floodplain rehabilitation E2 Ecosystem services F River governance: uncertainties, participation and collaboration F1 Uncertainty F3 Collaboration G Communicating programme: G1 Virtual River/serious game H Self-Supporting Hydrosystems and Valorisation H2 Wealthy Waal: Environment and valorisation H3 Export possibilities Possible links with H1 Hydrosystem module Ecosystem module Rules of thumb side channel morphodynamics Idem for natural banks Possible links wrt optimization of measures Monitizing nourishment Monitizing dredging Succession following landscaping measures Succession following landscaping measures Most important ES and their value Introduction of noise for deterministic runs Give feedback on choices made Possibly, the virtual game would be based on the meta model, to be determined Ecosystem service value and effects on vegetation distribution Sales of the conceptualization of the metamodel Planning first year, task A S O N D J F M A M J J A S O N D 1 Compilation of data Baseline, WAQUA, ecotope maps End user requirements 2 riverscape development Positioning measures Deriving bathymetry, ecotopes, and succession Convert to WAQUA input Drive WAQUA, BIOSAFE, EcoSys and aggregate output 3. Monte Carlo run of riverscape Create 100 river realisations Aggregate into longitudinal profiles and feature space Determine Pareto front and evolution paths 4. End user quality and relevance check Advisory commission X X

4 References Baptist, M.J. (2005). Modelling floodplain biogeomorphology. In, Civil engineering (p. 195). Delft: Delft Technical University Haasnoot, M., Middelkoop, H., Offermans, A., Beek, E., & Deursen, W.A.v. (2012). Exploring pathways for sustainable water management in river deltas in a changing environment. Climatic Change, 115, Straatsma, M.W., van der Perk, M., Schipper, A.M., de Nooij, R.J.W., Leuven, R.S.E.W., Huthoff, F., & Middelkoop, H. (2013). Uncertainty in hydromorphological and ecological modelling of lowland river floodplains resulting from land cover classification errors. Environmental Modelling & Software, 42, Figure 1 Flow chart of the landscape evaluation decision support system.

5 Figure 2 A) Pareto front of optimal set of river landscaping measures, b) temporal development of landscaping measures under two different management stategies