The à Âtaki River is located in the KÃÂpiti Coast District in the North Island of New Zealand. The river drains a catchment area in the western slopes of the Tararua Ranges, and flows west through a coastal flood plain south of the à Âtaki township to its mouth in the Tasman Sea.
The headwaters of the à Âtaki River are in the steep slopes of the western Tararua Ranges. The catchment area of extends from Mt. Pukematawai in the north, down along the main range to Mt. Aston in the south. The river flows through deep valleys and gorges in the foothills to à Âtaki Forks, where it is joined by the Waitatapia and the Waiotauru and then the Pukeatua (known as Roaring Meg). After continuing through à Âtaki Gorge towards KÃÂpiti Coast, the river flows through a coastal flood plain. It crosses State Highway 1 (SH1) south of à Âtaki and reaches the Tasman Sea south of the settlement of à Âtaki Beach. Around 80% of the catchment area of the river is within the Tararua Forest Park.
The à Âtaki River is the largest catchment area in the western Tararua Ranges and one of the largest rivers by volume flowing from the Tararua Forest Park.
The à Âtaki River is one of the major rivers that formed the fertile floodplains of the KÃÂpiti Coast. The à Âtaki Forks area, accessible via à Âtaki Gorge Road, is a popular recreational area and the start of several tramping tracks into the Tararua Range.
The à Âtaki River has a long history of flooding. Major events in the 20th century caused widespread damage to farmland and settlements on the floodplain. To reduce risk, the Greater Wellington Regional Council has built and maintained a system of stopbanks, rock groynes, and floodways, most notably at Chrystalls Bend. Gravel extraction has also been used to manage the riverbed and control flood levels, although this has led to erosion and adversely affected the natural character and the habitat provided by the river.
The river supports a wide range of native freshwater species, including longfin eel (Anguilla dieffenbachii), inanga (Galaxias maculatus), and other whitebait species. The estuary and lower reaches are used as feeding and breeding sites by waterbirds such as black shag, pied stilt, and variable oystercatcher. Toxic algae (cyanobacteria) blooms have occasionally been recorded in summer, leading to public health alerts.
The river is of major cultural importance to NgÃÂti Raukawa ki te Tonga and local hapà « of the KÃÂpiti Coast. It has traditionally been a source of food (mahinga kai) and a site for settlement and travel. According to oral history, the name à Âtaki derives from Haunui-a-nanaia, who named places along the lower North Island.
The estuary has been threatened by illegal dumping of rubbish, invasive weeds, and ongoing pressures from farming and urban development. Stormwater runoff and nutrient enrichment affect water quality in the lower river. Climate change is expected to increase flood risk through heavier rainfall events and sea-level rise.
The river and its surrounds are popular for swimming, kayaking, tramping, and fishing, especially that of whitebait and trout. à Âtaki Forks is a gateway to Tararua Forest Park, offering numerous tracks and campsites. The Friends of the à Âtaki River community group has developed walkways, planted native trees, and built a viewing platform at the estuary.
It was reported in 1863 that the river contains "what appears to be vein stones of carbonate, of lime in soft slate, are found in grade quantities."