In the period following the initial construction of the dam in the late 1970s, the lake began to deteriorate due to low rainfall and poor water flows, which saw lake weed overtake the swimming areas. The lake weed eventually became a drowning hazard that claimed the lives of swimmers over the preceding decade. In this sense, the project was a failure, and Lake Moana-Nui was considered unsafe. In an effort to control the problems, signs were erected banning access to the dam wall, and basic handrailing was put up to prevent public access. The lake was subject to regular draining in an effort to control the weed and to flush out the stale, stagnant water. While this did slightly improve the situation in the short term, people were warned not to swim in it. The lake is undergoing a major cleaning project so that it can be used in the future. To date (as at 25 April 2015), Lake Moana-Nui has been fully drained, refilled, and restored - and has been cleared by the local council for public recreation (as it was in its heyday during the 1970s and 80's).