river, towards the mouth, known as the "Great Swamp" in the 19th century; Makerua Swamp further inland, to the south of the Manawatū and north of the Tokomaru River, which covered 22000 acres; and Taonui Swamp on the north side of the river. The main vegetation in the swamps was harakeke and raupō: harakeke in the drier parts, raupō in the wetter. The Manawatū river mouth and estuary was listed under the Ramsar Convention as a Wetland of International Importance in 2005. Flooding The Manawatū River flooded in February 2004, displacing over 3000 people (primarily from Marton and Feilding) and damaging over 1000 Manawatū farms. The cost of the flood in terms of insurance payouts was NZ$122 million. Further damage was prevented by the opening of the Moutoa floodgates, which intercept the river between Foxton and Shannon. Water quality In 2018 a case study on water quality in the Manawatū-Whanganui region was jointly commissioned by Horizons Regional Council and the Ministry for the Environment, the study was conducted by Land Water People (LWP) and the results were reviewed by the National Institute of Water and Atmospheric Research (NIWA) and StatsNZ. Results showed that water quality for sediment and E. coli had improved over the previous seven to ten years in the Manawatū-Whanganui region. The report found strong statistical evidence of a connection between regional scale water quality improvements and local scale interventions. In 2006 Fonterra were criticised for an application to discharge of wastewater into the Manawatū River. In 2009, the Cawthron Institute found that the river had the highest gross primary production (GPP) compared to 300 rivers and streams in the Western world. High GPP rates are an indication of poor ecological health and can lead to various environmental issues. In 2011, the Horizons Regional Council laid blame with the Palmerston North City Council for "considerable" and "sustained" breaches of one of its discharge consents, and some degree of non-compliance with two others. A report by the Ministry for the Environment ranked 76 New Zealand sites for water clarity and E. coli levels. Using those measures, they found only four other New Zealand rivers rate worse than the Manawatū (the Waitara, Whanganui, Waipā and Rangitīkei). Notes References External links State of New Zealand's Environment 1997 - Chapter 7: Nature of NZ's water environment [Ministry for the Environment] Rivers of Manawatū-Whanganui Rivers of New Zealand