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The development of the bilateral Long Term Vision for the Scheldt Estuary between 1999 and 2001 reveals that it is possible to move from a history of conflict to cooperation in just two years. A retrospective, insider perspective is used to analyse the integrated three-layer hybrid modelling at the heart of this groundbreaking agreement. We tell an untold story of the collaborative eco-morphological modelling activity that served as a boundary object supporting communication and contributing to a model-based metaphor of the intrinsic character of the estuary – its most lasting contribution. [ABSTRACT FROM AUTHOR]

Water renewal and flushing in small, intermittently open or closed estuaries is receiving increasing attention particularly in light of the climate change induced alterations in run-off, wave and sediment transport conditions along coasts. The challenges of predicting the stratification-circulation state and the balance between tidal or freshwater flushing in response to the mouth dynamics of small, wave-dominated estuaries is the focus of the paper. Such predictions are required for determining estuary freshwater requirements or establishing an estuary's capacity to maintain sound water quality under pollutant discharges. Advances in simulating changes in stratification-circulation over long time scales are limited. Instead attention has focused on generating indices of stratification or water quality state using heuristic methods. In this paper, systems dynamics modelling is applied to simulate the non-linear response of the estuary to changes in river and marine water fluxes. The estuary is modelled as a basin with a specified water volume to water level relationship, connected to the sea by a channel with variable sill height, but fixed width. The direction and magnitude of the flow through the mouth determines whether the sill height erodes or accretes and hence the mouth dynamics (see Slinger, 2017). The tidal flux through the mouth co-determines the volumetric exchange of salt, influencing both the stratification state of the estuary and the degree of tidal or freshwater flushing. This is also influenced by run-off. The resulting dynamic balance is captured in two bulk indices, the Estuarine Richardson number and the bulk densimetric Froude number. Using measured data from the Great Brak Estuary, South Africa, the model is calibrated. Model simulations demonstrate the importance of tidal flushing and concomitant mouth breaching for water renewal as freshwater flushing declines under scenarios of increased water abstraction. Although the estuary remains partially mixed, there is increased average salinity and a more uniform the water column. Water releases and mouth breaching bring about a more natural stratification-circulation state, but these effects are short-lived. • Parametric simulation of water renewal in wave-dominated, intermittent estuaries. • A stratification index analogous to the Estuarine Richardson number is modelled. • A circulation index analogous to the bulk densimetric Froude number is simulated. • Stratification-circulation simulations indicate increased water column uniformity. • Mouth breaching & floods temporarily allow more natural stratification-circulation. [ABSTRACT FROM AUTHOR]

In the context of a growing emphasis on research and application of citizen engagement methods in environmental planning and management (e.g. Reed 2008; Von Korff et al. 2010), we compare three collaborative activities aimed at finding innovative coastal policy solutions in the Netherlands. In these activities, participants across the citizen, science and policy divide were involved in designing nature-based interventions for specific areas in the Netherlands. The activities are compared in terms of the theoretical promise stakeholder engagement holds for influencing participants' understanding of the respective bio-geophysical systems, the actor networks and for effecting knowledge sharing. We find local knowledge offers the potential for crafting coastal policy solutions to fit the specific bio-geophysical and societal context. The empirical analysis revealed the deep competence of local people, who generally understand their lived environment in a systemic way, and the knowledge that can be harvested to broaden and enrich the design space for coastal solutions – in addition to a willingness on the part of the stakeholders to collaborate in developing local solutions for sustainable futures. Although measures to reduce power differences and enable local knowledge inclusion served to broaden the design space for innovative solutions in our case studies, they also constrained the scientific and technical quality of the contributions from professional experts such as bio-geophysical scientists, engineers, spatial planners and policy analysts. As such, future work addressing the dilemma of integrating high quality professional inputs into coastal policy solutions founded on local expertise is advocated. [ABSTRACT FROM AUTHOR]

Small, intermittently open or closed estuaries are characteristic of the coasts of South Africa, Australia, California, Mexico and many other areas of the world. However, modelling attention has tended to focus on big estuaries that drain large catchments and serve a wide diversity of interests e.g. agriculture, urban settlement, recreation, commercial fishing. In this study, the development of a simple, parametric, system dynamics model to simulate the opening and closure of the mouths of small, wave-dominated estuaries is reported. In the model, the estuary is conceived as a basin with a specific water volume to water level relationship, connected to the sea by a channel of fixed width, but variable sill height. Changes in the form of the basin are not treated in the model, while the dynamics of the mouth channel are central to the model. The magnitude and direction of the flow through the mouth determines whether erosion or deposition of sediment occurs in the mouth channel, influencing the sill height. The model is implemented on the Great Brak Estuary in South Africa and simulations reveal that the raised low water levels in the estuary during spring tide relative to neap tide, are occasioned by the constriction of the tidal flow through the shallow mouth. Freshwater inflows to the estuary are shown to be significant in determining the behaviour of the inlet mouth, a factor often ignored in studies on tidal inlets. Further it is the balance between freshwater inflows and wave events that determines the opening or closure of the mouth of a particular estuary. [ABSTRACT FROM AUTHOR]

The Incomati River Basin is shared by Mozambique, South Africa, and Swaziland. In August 2002, the groundbreaking "Tripartite Interim Agreement on Water Sharing of the Maputo and Incomati Rivers" (the IncoMaputo agreement) was signed. Following reports that the use, availability, and adequacy of information posed problems for future decision making on this transboundary river, the Delft University of Technology initiated a 6-month study in 2003 in which 25 southern African researchers and officials were interviewed. The Joint Incomati Basin Study (Phase I from 1992--1995, and Phase II from 2000--2001) formed a central component in the investigation, because it was viewed by the parties involved as a successful experience that paved the way for the IncoMaputo agreement. Knowledge of the role that information played in this process and how decision making occurred was collated and analyzed. Network theory provided the guiding theoretical framework in interpreting the results. A number of problems related to information use in decision making were identified. More importantly, a web of underlying causes was identified, such as cultural and language differences, differences in perception, inadequacy of stakeholder involvement, variability in political commitment, lack of capacity, absence of operational experience, the weak mandate of the international decision-making body, and the paradoxical South African--Mozambican relationship. Two groups of factors in this web were identified as needing to change if the management of this transboundary river is to comply with the IncoMaputo agreement, namely the situational or institutional factors and the cognitive factors (particularly the perceptions each country holds of the other and the way they treat one another). Our analysis shows that, contrary to current international practice, when designing international institutional arrangements for water management, the sociopolitical interface should be considered as important as information flow to the water managers. [ABSTRACT FROM AUTHOR]

In 1990, the environmental impacts of an upstream dam on the Great Brak town and estuary were assessed and a management plan and monitoring programme were devised. In a recent review of the monitoring results, planned water releases and interventions in the form of timely mouth breaching were found to have ensured that, although the estuary's abiotic functioning has altered, its biotic health has not deteriorated over the last ten years. The lessons learned are captured in the revised management plan of 2004, which exhibits a clear shift to explicit communication plans and operational procedures, in-dicating that the initial environmental impact assessment (EIA) products were rudimentary. We argue that learning-through-doing and active public participation in the Great Brak case are essential ingredients in the adaptive management that is fundamental to successful EIA follow-up. [ABSTRACT FROM AUTHOR]

Institutional work offers a promising lens for understanding institutional change, focusing on the efforts of actors in creating, maintaining or disrupting institutions. In this paper, we explore the capacity of a narrative approach to provide insights on institutional work, using a case study from the coast of Sweden. We identify four narratives that compete in the policy discourse regarding erosion and beach nourishment in the coastal province of Scania. The narratives reveal that actors hold different beliefs concerning the magnitude of the erosion problem, the division of responsibilities and the suitability of sand nourishment as a coastal protection measure. The narrative competition is considered reflective of past institutional discussions and ongoing institutional work in coastal management in Scania, confirming that narratives are used as sense-making and meaning-giving devices in institutional discussions. [ABSTRACT FROM AUTHOR]

In the face of a changing climate, many cities are engaged in adaptation planning and are using participatory workshops to involve stakeholders in these initiatives. Different tools are being used to structure the process and content of participatory planning workshops, but it is unclear what effect the tools have on the workshops and their results. We evaluated three different tools (Group Model Building, the Adaptation Support Tool, and the Stress Test Guideline) and a tool-free approach in repeated simulated workshops, to observe and compare (1) the way workshops played out, and (2) the direct outcomes that were achieved. Tools appear to influence both aspects. Specifically, we measured differences in the learning effects in groups, in the development of shared understanding within groups, in the types of plans that are developed by groups, and in the nature of participation during the workshops. Further research is needed to translate these results into practice, but this is a first step in advancing knowledge about the influence of tools in participatory planning activities. [ABSTRACT FROM AUTHOR]

Planning Support Systems (PSS) are a promising tool for involving stakeholders in urban adaptation workshops. Past research has focused on the use and added value of PSS. While earlier studies have widely acknowledged the importance of context in determining the effectiveness of PSS, there has so far been no dedicated study of the influence of context on the use and added value of these tools in real planning workshops. To address this gap, we made an in-depth exploratory case study of a PSS, called the Adaptation Support Tool (AST), used in an adaptation planning workshop in Guayaquil, Ecuador. The workshop used the AST to support collaborative spatial planning for urban water management, at the neighbourhood scale. Interviews, questionnaires, observations and document review were used to investigate the influence of three contextual factors on the use and added value of the AST. The studied contextual factors are: 1) the style of tool use, 2) the phase of planning, and 3) the local project setting. Our findings indicate that the style of tool use and the local project setting were the most important contextual factors in determining the use and added value of the AST during the workshop. Meanwhile, the phase of planning appears to be critical for achieving impacts at the project level. This exploratory case study is a modest first contribution to understanding the influence of context on the use and added value of PSS in practice. Nevertheless, the findings indicate that further exploration of this topic could offer important insights to PSS use in practice. The influence of context on the use and added value of Planning Support Systems in workshops: an exploratory case study of climate adaptation planning in Guayaquil, Ecuador. • A case study that explores the influence of context on the use and added value of a PSS in practice • Contextual factors studied include: the style of tool use, the phase of planning, and the local project setting • For style of tool use, the physical manner of use and facilitation were important • For phase of planning, the tool's use early on led to a creative workshop, but limited impacts on the project • For local setting, the PSS overcame cultural barriers to collaboration and provided insights to social-economic development [ABSTRACT FROM AUTHOR]