Table 2. Impediments to achieving effective delivery of water to the Marshes. Impediment Explanation Biophysical Insufficient water allocated to the environment in water sharing plans to sustain the wetland The volumes of water allocated to environmental flows are insufficient to maintain the ecological character of the Marshes (see Table 1 and underlying convictions) Natural tributary flows, used as additional irrigation resources, no longer reach the Marshes When rain enters the Macquarie River below the dam through tributaries, water release from the dam intended to service irrigation is reduced, and the tributary flows are used instead. However, tributary flows, which account for approximately 10% of the total amount of catchment water that would naturally have entered the Marshes, could significantly contribute to achieving: (1) larger floods and (2) more natural variability. Flow of water for irrigation occurs at a different time of year than rainfall periods Water is released from the dam for irrigation and stock watering during the summer months and may, therefore, enter the Marshes during this period. Rainfall in the upper catchment usually occurs during winter. Physical impediments on the floodplain Urban and agricultural development on the floodplain upstream of the Marshes creates a bottleneck, making it difficult for large volumes of water, which are necessary for widespread flooding, to reach the wetlands. Size of release valves in the dam The small valves prevent the release of large volumes of water, which reduces the capacity for flooding the wetland. Large floods on the wetland are only possible when the dam spills, which is a rare event. Translucent flows Translucent flows aim to mimic a natural flow of water out of the dam by releasing water when it rains in the upper catchment. However, because of the size of release valves, only low volumes can be achieved . This process has failed to reproduce natural conditions and has contributed to channel erosion. Political Lack of will/ability to make significant changes Many politicians at the state and federal level appear unwilling or unable to act to achieve changes that will help to achieve effective water delivery. This is partly due to (1) the lack of public awareness about the ecological state and importance of the Marshes and, hence, lack of public support for politicians to take difficult decisions; (2) pressure from an irrigation industry that has substantial economic leverage and has considerable lobbying power; and (3) the perception that the region has “safe” electoral seats, which reduces politicians’ willingness to make policy changes. Social Threat of litigation Previously, Macquarie River Food and Fibre, representing individuals who have developed agricultural enterprises on the floodplain, have threatened legal action against water agencies if access to their properties is restricted by large releases of water from the dam. This (1) creates pressure on the water agencies to conform to the requests of irrigators, and (2) decreases the possibility of achieving medium to large floods on the Marshes. Public perception that the Marshes are healthy There is a general perception in the region that the Marshes are either healthy, or are within a natural drought period. This means that people are (1) less concerned about the Marshes, and (2) are less willing to support political actions. Public perception that the Marshes receives a lot of water Water released from Burrendong Dam to service irrigation, stock, and domestic use upstream of the Marshes generates a perception in the region that the Marshes receives a lot of water. This is despite the problem that the volume of water is significantly less than that which the Marshes would have received historically, and that much of the continuous low volume flows that reach the Marshes goes round the wetland via the Northern Bypass Channel to service downstream users. Lack of general public interest in the conservation of the Marshes There is a lack of public knowledge about the Marshes. Despite the size of the wetland, many people who live in the region have never visited them. Institutional Lack of will/ability to enforce floodplain restrictions It appears that the water agencies are incapable of enforcing floodplain regulations. This can be due to (1) lack of resources, or (2) inability to deal with the pressure from different stakeholders. For example, in recent meetings of the local floodplain management committee, for managing areas upstream of the Marshes, representatives of the Macquarie Marshes Management Committee and the National Parks and Wildlife Service (NPWS) have been barred by private landholders from conducting site visits to assess impacts of floodplain development. The water agencies, which have been allowed access, have resorted to a reassessment of the water flow models, at considerable cost, rather than enforcing previous decisions. Policies preventing dam spills Water agencies appear to ensure that as much water as possible entering the dam can be retained for allocation to different stakeholders. This also includes maintaining “air space” to ensure that if it does rain, then no water is “wasted” through dam spills. Lack of neutrality of government water agencies The managers provide numerous recent examples of policies and management by water agencies that favour the interests of the irrigation industry over environmental and other interests (see text).