Phillips, Christopher J.Nelson, Campbell S.2010-11-022010-11-021981-12-01Phillips, C. J., & Nelson, C. S. (1981). Sedimentation in an artificial lake ‐ lake matahina, bay of plenty. New Zealand Journal of Marine and Freshwater Research, 15(4), 459-473. https://doi.org/10.1080/00288330.1981.95159380028-8330https://hdl.handle.net/10289/4737Lake Matahina, an 8 km long hydroelectric storage reservoir, is a small (2.5 km2), 50 m deep, warm monomictic, gorge‐type lake whose internal circulation is controlled by the inflowing Rangitaiki River which drains a greywacke and acid volcanic catchment. Three major proximal to distal subenvironments are defined for the lake on the basis of surficial sediment character and dominant depositional process: (a) fluvial‐glassy, quartzofeld‐spathic, and lithic gravel‐sand mixtures deposited from contact and saltation loads in less than 3 m depth; (b) (pro‐)deltaic‐quartzofeldspathic and glassy sand‐silt mixtures deposited from graded and uniform suspension loads in 3–20 m depth; and (c) basinal‐diatomaceous, argillaceous, and glassy silt‐clay mixtures deposited from uniform and pelagic suspension loads in 20–50 m depth. The delta face has been prograding into the lake at a rate of 35–40 m/year and vertical accretion rates in pro‐delta areas are 15–20 cm/year. Basinal deposits are fed mainly from river plume dispersion involving overflows, interflows, and underflows, and by pelagic settling, and sedimentation rates behind the dam have averaged about 2 cm/year. Occasional fine sand layers in muds of basinal cores attest to density currents or underflows generated during river flooding flowing the length of the lake along a sublacustrine channel marking the position of the now submerged channel of the Rangitaiki River. © 1981 Taylor & Francis Group, LLC.application/pdfenThis article has been published in the journal: New Zealand Journal of Marine and Freshwater Research. © 1981 The Royal Society of New Zealand.Lake Matahinalacustrine environmentslacustrine sedimentslacustrine sedimentationsedimentation rateshydro-electric storage lakesJournal Article10.1080/00288330.1981.95159381175-880537 Earth Sciences3709 Physical Geography and Environmental Geoscience3705 Geology31 Biological sciences37 Earth sciences41 Environmental sciences7 Affordable and Clean Energy