Natural salt pollution from geologic formations in the upper watersheds of several large river basins in the Southwestern United States severely constrains the use of otherwise available major water supply sources. The Water Rights Analysis Package modeling system has been routinely applied in Texas since the late 1990s in regional and statewide planning studies and administration of the state’s water rights permit system, but without consideration of water quality.

During the past three decades, the Pisque watershed in Ecuador's Northern Andes has become the country's principal export-roses producing area. Recently, a new boom of local smallholders have established small rose greenhouses and joined the flower-export business. This has intensified water scarcity and material/discursive conflicts over water use priorities: water to defend local-national food sovereignty or production for export.

The ideal water contract for a heterogeneous population of users is a prioritized right that is fully vested and fully tradable. A set of tradable, prioritized rights contracts will span the same space as the Debreu contingent commodities. Therefore, they lead to a competitive equilibrium that is Pareto optimal. Equal sharing of water shortfalls does not have this property.Existing water policies in Israel and the Disputed Territories are not characterized by an efficient set of water contracts.

The paper looks at the institutional and policy reforms in the context of sources and uses of water. Although the reform measures have been specific about surface water, there still is ambiguity on the groundwater situation in India. The reforms have failed to de-link the conventional linkages between right to land and right to (ground) water. Most policy reforms have been in response to the emerging crisis of water allocation, use and management.

In many countries around the world, increasing attention is being directed to the need to improve water rights systems. This paper is based on a recent study undertaken to investigate challenges facing optimal implementation of formal water rights systems for irrigation purposes in the Great Ruaha River Catchment in Tanzania. The study integrated social survey, hydrologic, water abstraction and water use data, and Geographical Information System techniques.