Within western ecosystems the presence or lack of free surface waters may govern the ability of wildlife species to utilize a particular geographic location, as many game and non-game wildlife species must have access to free water during part or all of their annual life cycles. Most water development projects on western rangelands are designed to provide water to domestic livestock, while some developments are created specifically for wildlife. In some cases, where a natural water source may have served the needs of area wildlife over time, the same surface waters may not be sufficient to meet the needs of large domestic animals or of concentrated groups of domestic animals. The answer to this situation has been to construct water developments throughout the arid and semi-arid west. However, there is increasing public concern that livestock water developments on public lands in Idaho and adjacent western states may provide very limited value, if any, to resident or transient wildlife species. Yet water development proposals presented to the public for approval frequently indicate that a major factor for project authorization is that of providing benefits for wildlife. Another major justification for livestock water developments is to provide for habitat improvement. While some benefits may occur to resident or migratory wildlife species through the construction of particular types of water developments, there is growing concern that the overall ecological impacts of water developments do not justify their construction and placement within natural habitats. Another source of public dissatisfaction with agency management regarding water developments and other range “improvements” is the failure of agencies to actually carry out management actions that meet stated objectives for wildlife. While agency personnel and livestock permittees may be annoyed with the increasing public scrutiny of their actions, we must remember that the public has a vested interest in the responsible and sustainable management of public lands. As livestock grazing is the most widespread human activity occurring on our public lands today, it thus receives the lion’s share of public concern and requests for accountability. The following report is not intended to serve as an all-encompassing treatise on livestock and wildlife interactions, of which there are many. The intent of this report is to provide information to the reader/viewer regarding livestock water developments and associated wildlife and public issues- issues that may not be routinely identified or addressed by public (or private) land managers. This report provides an introductory discussion of arid ecosystems and the relationship of wildlife to water resources. Report sections include background information relating to livestock and wildlife water developments. This report also provides a discussion of major ecological costs (impacts) associated with livestock water developments, discusses the impacts of livestock water developments on wildlife populations, and introduces major safety and access issues relating to water developments. This report also documents and discusses major failures of western land management agencies to maintain wildlife-friendly livestock (and in some cases wildlife) water developments. A final chapter explains why water developments on public lands may represent substantial violations of the public trust. This report has been peer reviewed by agency and industry professionals with natural resource and livestock management expertise.