Table 2. Major barriers to the implementation of IWRM and AM concepts Barrier IWRM AM Research agenda Institutional Effective water governance is crucial for the implementation of IWRM plans. Problems in management and governance go beyond mere technical challenges; in the case of IWRM, institutional reform is needed: correct policies, viable political institutions, workable financing arrangements, self-governing and self-supporting local systems, etc. Institutions are rooted in a centralized structure with fragmented subsectoral approaches to water management, and often local institutions lack the capacity. Awareness and priority of water issues at the political level is, in many cases, limited. Also information and data to support sound management of water are generally lacking. It is said that institutional challenges may be the key barriers to implementation of AM, and that AM may be a tool for enhancing institutional effectiveness. Social dynamics and institutional rigidity may complicate the implementation of the AM approach. Learning is information intensive and requires the active participation of many stakeholders, who need to maintain a commitment to the learning process throughout. Sound adaptive water management relies on functioning institutions that are designed to accommodate changes and new information. This institutional base is crucial for sustainable water resources management and development. Also, a long-term source of funding is crucial for the AM approach, which should include all steps of the process. What institutional and governance structures and processes are needed to successfully implement IWRM or AM? Are they practically feasible? What would be required to change from existing structures and processes? And, importantly, why should political leaders embark upon a potentially radical overhaul of management practices? Evidence of success The necessity of adapting the IWRM concept to suit different local contexts does not allow for a generic, complete description of strategies and techniques. In practice, the IWRM concept has not structurally demonstrated its ability to increase the sustainability of water resources management. Empirical evidence is either missing or poorly reported. It will be important to identify the essential elements for IWRM, while avoiding rigid prescriptions and allowing for vast differences among countries. AM is a form of systems analysis that includes and performs many feedbacks between sectors, rather than narrow technical analysis, and uses conceptual qualitative modeling rather than formal quantitative modeling. The drawback of this soft approach is that it is not easily reportable or demonstrable because it does not provide quantitative results. Also, the AM approach has merged into a more generic process, which could jeopardize the intended flexibility of the approach. It is important here to identify short-term strategies in the face of long-term uncertainty. How can evidence be gathered to show that management frameworks like IWRM or AM are successful? Gathering evidence to show the value of implementing these approaches may be a necessary prerequisite to convincing political leaders to instigate institutional and governance reform. However, existing evidence is not Ambiguity of definition The most used definition of IWRM by the GWP gives very limited practical guidance to present and future water management practices. Besides the GWP definition, there are several other definitions that all differ from each other in one or more facets or dimensions. Ambiguity of definition further compounds difficulties in demonstrating success. A reason for failure to achieve widespread adoptation and a rather modest success when adopted is the failure to define what exactly is meant by AM, and how it should be implemented. The AM concept has multiple and often ambiguous definitions. Resource managers may not understand what AM is and how they can apply it in practice. What exactly is IWRM? What exactly is AM? The literature contains incomplete, ambiguous, and sometimes even contradictory definitions, partly because of the thrust for genericity behind both approaches. Is such diversity of understanding a strength, a weakness, or a necessity given the wide range of social, economic, and environmental contexts that IWRM and AM are supposed to benefit? Complexity, cost, and risk IWRM takes into account relationships and dynamic interactions between human and natural systems, land and water systems, and key stakeholder agencies and groups. This interconnectedness on different scales and levels makes it very complex to translate the IWRM concept into practice. Management problems end up with ambiguous boundaries and complex links with other problems; goals, alternatives, and consequences that are not well defined or understood; pervasive uncertainty that may not be quantifiable; and iterative management that involves conflict and negotiation among multiple stakeholders with divergent interests and values. Stakeholders may view experimental management as too time consuming, complex, and costly, and more ecologically and economically risky. They may be unwilling to accept experiments without knowing the consequences. AM is considered difficult to initiate and sustain, and unlikely to be affordable in many instances. AM is likely to be costly and slow in many situations, so those involved in stewardship should thoroughly consider whether this approach is worthwhile in all cases. New information must be collected and processed by management actors to draw meaningful conclusions and implement appropriate action. Providing such information is a difficult, costly task. How are the lessons of complexity science to be communicated to stakeholders, and how do we formulate convincing arguments about the roles of uncertainty, sub-optimality, and diversity. What kinds of financial, administrative, and social relationships best support IWRM and AM approaches.