Multi-Agency Investigation Targets Ecological Collapse at Manawatū Dune Lake

DOC and Horizons Regional Council investigate the drying of Pukepuke Lagoon after 3,000 eels were rescued. Experts look at land use and drainage as causes.

By: AXL Media

Published: Apr 27, 2026, 3:48 AM EDT

Source: RNZ Pacific

Immediate Crisis and Community Response

The ecological emergency at Pukepuke Lagoon, located between Himatangi and Tangimoana, became apparent roughly a fortnight ago when the 15-hectare lake bed was found completely dry. In response, volunteers from the Rangitāne o Manawatū Settlement Trust and other local iwi mobilized to rescue approximately 3,000 eels from the receding mud. Despite these efforts, the lake bed remains littered with dead aquatic life. The lagoon, while smaller than its historical footprint, serves as a vital dune lake ecosystem, making the sudden disappearance of its water a high-priority concern for conservationists and indigenous stakeholders.

Investigating Land Use and Hydrological Changes

Horizons Regional Council chief executive Michael McCartney has confirmed that an independent probe is underway to scrutinize the surrounding landscape. A primary focus of the investigation is the potential impact of neighboring land use, including intensive farming and forestry operations. Local iwi have expressed concerns that these activities may have altered the local water table or surface runoff patterns. Investigators are currently analyzing environmental data, including groundwater levels and comparative lake levels from the broader Manawatū area, to see if Pukepuke’s drying was an isolated incident or part of a wider trend.

Technical Surveillance and 3D Mapping

To support the investigation, officials have completed a LiDAR (Light Detection and Ranging) survey of the lagoon and its environs. This remote sensing technology has created highly detailed 3D images of the landscape, allowing experts to identify subtle changes in topography. Specifically, authorities are looking for evidence of "additional drains" or unauthorized digging that may have diverted water away from the lagoon. This topographical mapping will be compared against historical data to determine how significantly the height of the lake bed and its connectivity to the surrounding water system has shifted over time.