9e3091e4-07ee-0b06-ac5c-68cea819dd75 eng utf8 dataset custodian NIWA National Institute of Water and Atmospheric Research +64 4 386 0300 voice +64 4 386 0574 facsimile 301 Evans Bay Parade Hataitai Wellington 6021 New Zealand curator@niwa.co.nz http://www.niwa.co.nz Website of the National Institute of Water and Atmospheric Research, New Zealand - Enhancing the benefits of New Zealand's natural resources. Data curator 2015-06-17T16:56:06 creation ISO 19115-3 urn:ogc:def:crs:EPSG::4326 OGP NZST/NZDT Historical bed-level change at seven cross-sections along the lower Rakaia River 2015-06-16T04:18:00 creation 2015-06-16T04:18:00 revision This investigation analyses historical bed-level change at seven cross-sections along the lower Rakaia River between around SH1 Bridge and the coast using data from ground surveys undertaken in 1976 and 1988/89 and from airborne LiDAR flown in 2010. It is concluded that with a few exceptions, mean bed levels along this reach appear to have been stable - at least within the level of detection and allowing for natural variation in bed levels associated with normal braided riverbed dynamics. A slight degradation trend of a few mm/yr is consistent with a response to long term coastal retreat, at least for the river within about 18 km of the coast. It is likely that much of the 0.75 m of degradation apparent over the active braidplain of the South Branch 10 km upstream from the coast between 1988 and 2010 is an artefact of errors in re-locating the section line. The investigation included: 1) Securing the historical ECan survey records and entering them into a spreadsheet. 2) Extracting the 2010 bed-levels from the LiDAR along the ECan section lines 3) Post-processing the LiDAR topography to remove remnant bias from returns off riparian vegetation. 4) Using flow-gauging data to develop a relationship between wetted cross-section area and river flow rate for use in adjusting the LiDAR mean bed-levels to include wetted bed areas 5) Plotting the overlaid sections and calculating changes in mean bed-level reporting. To determine if the mean bed levels along the lower Rakaia River have changed between 1976 (or 1988) and 2010. Hicks, D. M., Bind, J. (2015). Bed level change in the lower Rakaia River, 1976-2010. NIWA CLIENT REPORT No: CHC2015-012, NIWA Project: SCJ15501/13. p. 17 + appendix. Work funded by William Southward. completed pointOfContact NIWA Murray.Hicks@niwa.co.nz Murray Hicks Scientist author NIWA Jochen Bind Scientist vector inlandWaters Canterbury Region 174.264105,-42.099215 173.744383,-41.907383 173.463053,-42.117813 173.053389,-42.488129 172.721476,-42.103491 172.479033,-42.277029 171.710142,-42.903816 171.314245,-42.948149 170.615057,-43.431871 170.238184,-43.513901 169.699339,-43.963545 169.543104,-44.208303 169.641001,-44.596004 169.944216,-44.653984 170.094065,-44.940195 170.350157,-44.907763 170.387693,-45.078878 170.894705,-44.894241 170.8948,-44.894241 171.406801,-45.015368 171.616117,-44.37579 172.401239,-44.057322 172.998693,-44.098328 173.330328,-43.94791 173.371878,-43.635685 172.999571,-43.308992 173.462774,-43.075552 174.264105,-42.099215 169.543104 174.264105 -45.078878 -41.907383 2010-07-01T00:00:00 2010-07-31T00:00:00 1988-01-01T00:00:00 1989-12-31T00:00:00 Rakaia River historical bed-level change airborne LiDAR SCJ155REG theme NIWA Project Codes 2012-01-01 publication NIWA_ProjectCode Data used in this report are owned by ECan. Contact NIWA point-of-contact (email details above) in the first instance. Data owned by ECan restricted Hicks, D. M., Bind, J. (2015). Bed level change in the lower Rakaia River, 1976-2010. Prepared for W. Southward. February 2015. NIWA CLIENT REPORT No: CHC2015-012, NIWA Project: SCJ15501/13. p. 17 + appendix. largerWorkCitation eng First data were from 1976. https://dc.niwa.co.nz/niwa_dc/srv/metadata/9e3091e4-07ee-0b06-ac5c-68cea819dd75 WWW:LINK-1.0-http--metadata-URL Point of truth URL of this metadata record O drive Christchurch SCJ15501/13 dataset Rakaia River bed-level change data restricted