The article is devoted to the development of theoretical approaches to the formation and implementation of the strategy of water policy of Ukraine in the context of climate change. As a result of the conducted research, it is proved that because of influence of various external factors there are changes of basic imperatives of functioning of modern systems of management of water resources. The need to consider these changes by improving the strategic documents that define the priorities and principles of national water management policy is substantiated. It is established that one of the main reasons for the lack of water of good quality is its low value compared to other natural resources. This leads to a lack of legal, organizational, and financial and economic grounds for ensuring the payback of water and water-dependent ecosystem services, which is the reason for lack of funds and relevant work to improve and restore environmental and hydro morphological characteristics of reservoirs and repair and modernization of existing hydraulic structures. In this regard, emphasis is placed on the need to improve methods of economic regulation and the development of mechanisms and tools for financial support of sustainable water management. In the context of the above, it is proposed to include in the list of main tasks of the draft Water Strategy of Ukraine two groups of economic levers to increase the financial base of investment support for sustainable water management. The first group is aimed at improving the rent regulation of special use of water resources and provides for raising standards for unauthorized groundwater production, for companies that produce beverages and sell bottled drinking water, as well as limiting various benefits and preferences when paying special water use fees. The second - to change the system of water resources management, the development of institutional and legal support for their use in a globalized market environment, the implementation of modern instruments of financial and economic support for the formation of territorial water resources on a corporate basis.

One of the powerful factors behind the transformation of the components of the institutional environment that has evolved dynamically in recent decades is considered to be the environmental constraint, the main reason for which is the exacerbation of global environmental challenges and changes in the world-view of the modern world. In this regard, the study identifies and analyzes the patterns of transformation of conceptual approaches to the formation of a sustainable water supply system under environmental constraints. It is proved that one of the determining external factors that cause such transformation is the increase of environmental awareness of the population at the local, national and world levels. The system of methods of sustainable water supply in the conditions of ecological restrictions is proposed, which provides for complex scientifically grounded application of modern infrastructural, institutional and ecosystem mechanisms of water policy implementation and institutionalization of a number of strategic directions and processes of development of integrated water resources management of Ukraine. It is established that in the field of institutional support for sustainable water use, the evolution of conceptual approaches under the influence of «ecological» philosophy will determine, first and foremost, the improvement of the regulatory system of streamlining relations, its focus on optimizing the use of water resources, their conservation and reproduction. It covers all the main characteristics of the institutional environment, the system of rules and norms of behavior of economic relations, changes in the set of incentives for entrepreneurial activity and in the sphere of coordination of economic, financial and regulatory activities and state planning. Therefore, the strategic directions of transformation of the current water management system in order to ensure their expanded reproduction is the institutionalization of new rules and standards for the economic development of water resources, in particular the specification of ownership rights for water resources and the spread of modern forms of public-private partnership in the field of water use. This will increase the level of investment support for the reproduction of water resources and expand the available financial base for the modernization of water management infrastructure.

As a result of the study, it was proved that the existing water resources management system, which is built on the component, territorial-branch principle, causes extremely high and unacceptable economic, social and environmental costs at the present stage of human development. An alternative paradigmatic concept of forming an integrated water resources management system in Ukraine is proposed based on the basic provisions of the theory and methodology of neo-institutionalism. The main directions of organization of the institutional architecture of water resources management in the context of providing sustainable water use are determined.

Based on the generalization of international experience in reforming water management systems, a list of basic imperatives and principles, as well as the most common methods and tools of water policy development, which have been tested and successfully implemented in many countries. In particular, the study considers a number of principles of state sectoral policies and management of reform processes, including: the application of systematic multi-disciplinary approaches to assessing the state of natural and technical social systems; adherence to the principles of sustainable development and integrated management; stakeholder participation at all stages of policy development and implementation; implementation of the principles of good governance; use of technological innovations, informatization and application of platform technologies. Emphasis is placed on the fact that existing and promising sectoral strategies in the field of water protection and use should be based on a common intersectoral vision and the formation of relevant broader intersectoral strategic goals that address important national tasks of improving and developing water management. An algorithm of the process of interaction between stakeholders and expert groups in the process of developing the Water strategy is proposed, which provides for: accumulation and analysis of data on the state of water resources and water use; performing a systematic analysis of the functioning of the industry; development of a general vision of the future state of water resources management; substantiation of strategy principles and development of indicators for quantitative assessment of strategy implementation results; determination of the main stages of the strategy and methods of their implementation; development of qualitative and quantitative scenarios of institutional changes in the water management complex, as well as the necessary technical and technological innovations for the long term. It is substantiated that in order to ensure a transparent and clear process of development and implementation of the main provisions of the Water strategy, it is necessary to organize the national water dialogue with the participation of leading scientific and educational institutions in the field of water management.

The article deals with issues of management and financial support land use water resources Ukraine in terms of decentralization. It was established that one of the obstacles to decentralization in Ukraine is the lack of necessary funding infrastructure upgrades lands of water fund. The necessity of reforming the institutional system of water use on the lands of water fund, through the implementation of new institutional forms of economic development, water resources, focused on the water and agricultural needs of communities. In particular, they provide for the establishment of partnerships between the state and private enterprise entities and ensure diversification of investment water management and protection projects.