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cem todentity what has caused change in TRACING THE SEDIMENT IN N PELORUS SOUND How did we find this out? Marborough District Council commissioned NWA to study the sediment sources in Te Hoiere Pelonus Sound using the latest scientific techniques This study enables better understanding of how human-induced and natural erosion sources have contributed to sediment composition and accumulation and identfies the sources of sediment deposited in the iver and a part of Te Hoiere/ Pelonus Sound disturbed the natural land cover De Mahau Soun. Researchers colected samples of soits and sediment from Sound are subsoil, stream bank erosion, dairy pasture. vers and the inner Te Hoiere Pelorus Sound. Sampling Included topsols, subsolis he soils beneath the topsoi, iver The proportions vary according to the location and streambank sediment, fine sediment deposits in river channels, sediment cores from Mahau Sound, and surtace aged in acale, from localed impacts on cockie beds due to different organic carbon biomarker. Samples were taken marine sediment tom the entrance to Te Hoiere Pelorus Sound (Chetwode lslands Nukuwaiata and Te Kakahoj. Key findings Sediment is one of the main threats to New Zealand's manine environment and has impacts on treshwater ecosystems. The Mahau Sound over the last century were estimated using two of sol from the land and its depostion in estuaries and the sea is a natural process, but the rate sediment is being deposited is higher than before human activities Sediment accumulation rates SA0 in Havelock Estuary and independent radioisotope dating methods. Pre historic SAR in the Mahau Sound were derived from radiocarbon dating of cockle shels. The shelifish remains preserved in cores trom one of three stes sampied in Mahau were aralysed along with The main contributors to sediment in Te Hoiere/Pelorus Sediment sources were traced using CSS (Compound Specific Stabie iIsotopej mehods. This method was developed by NWA scientists in the mid-2000s and is now uned across the world. The method identifies sols by their harvested pine and native forests The effects of increased sol erosion and sedimentation have early Maori activtes in Mahau Sound to extensive catchment om sstreamside, iverbed and seafioor deposits at various wide sol erosion and sedimentation since European settiement Goldmining, native forest clearance, pastoral farming and more recent agricutural and forestry activites have al let locations. These were compared to land-ute and natural reference samples. Ths enabled uns to determine what proportion of the samples were from which erosion sBource hatural or humaninduced. For more info on CSSI, see https://niwa.co.nz/essi The full technical neport can be found here: www.mariborough. govt.nalenvironmentcoastal sedimentation their legacy in the Marborough Sounds waters This study enabled us to understand the sources of sediment deposited on the verbed, on the riverbanks, and in the marine environment. The sources for each iver sampled are displayed above, and in percentage terms in the pie chars overleal. Sediment deposited on the riverbed: the major sources of deposited fine sediment dounstream in the rivers are stream-bank and subsols the soils beneath the topso Stream bank erosion is pronounced in the Katuna and Tinine, upper Ra and Whakamarino Wakamarina subcatchments Subsol erosion hotspots occur in the Tinline. Whakamarino and upper Ra subcatchments e. Tunakino, Opouri and Brown + Sedment deposited on the verbank dairy patture and harvested pine are subtartial sources of deposited fne sediment on verbarks Harvested pre topsol cortributions re highest at the outiets of the Upper Pelorus. Brown, Ronga and Kaluma (Opour subcatchments. Sheep pasture topsols make the largest contribution to ver sedment deposited near the outiet of the Katuna River, Contributions of topsols from native forest and kanuka senbto iver sediment deposits are unitormly low across all sampling stes in the Pelorus- Raand Katuna catchmens Sediment sources Maud Kenepunu Inlet 000 Kelbma Str Dveen Chariotte Sound Maho Sound Havelock Hoiere /Peloras R San n Oury p Wakamarina Fedmen ompncanet nd Sediment deposited in the marine environment pee overieaf 70% of sediment deposited over the last century in Mahau Sound is egacy sediment. This marine sediment is utmately composed of sol eroded trom the surrounding catchments as well as deposited marine organie mater jag phyloplanitor transported to Mahau Sound Compared with the preceding -2.000 years, the sediment accumlation rate over the 20th century s10 times hghe Lngyh d me which h ntag too hohg tonga kmpur ondyn aen w ngto -ea dondn anping looo lal M Thirty percent of the deposited sedment comes trom contermporary land uses over the past century ee overleat. Subsols are the largest contributor, followed by stream-bank erosion. Native forest and Mahau Sound sediment sources Next steps This report provides greater understanding of the sedment dynamics of Te HoierePelorus catchment. Sedimeont acoumulation rates are 10 times greater since European settement. Mean sediment source proportion (%) O 20 40 00 80 100 o 20 4o 00 80 100 0 20 40 00 80 100 Sediment has accumulated in, and circulates within the sound over time. Contermporary sediment loads add to mis historic sediment. 2013 2013 2016 The report also shows that the issues caused by deposited sedment have a long history There is a large amount of egacy sediment in the sound that wil continue to cause environmental issues for some time after the mitigation of contemporary sources of sediment. The Te Hoiere Restoration project is a community-led project focussed on neducing the 200 2008 2012 2001 2003 2008 amount of sediment and other contaminants entering the Pelorus Sound Te Hoiere. This report is an impotant part of understanding what the sources of these sediments and oontaminants may be 2000 For more information: Oliver Wade Envieonmental Scientist - Coastal Marborough District Council Oliver Wademariborough.govt.nz Phone: 03 s20 7400 1974 1978 MARLBOROUGH |DISTRICT COUNCIL 145 142 1948 1937 1828 121 121 NIWA Core MH-1 MH-2 MH3 Taihore Nukurangi Harvested Pine Kanuka MARINE Native Forest Soub-Pasture Sources of sediment acoumulating in Streambank Subaol Mahau Sound ner Pelorince e eaty 20n century determined trom CSS analysis of dated cores TRACING THE SEDIMENT IN PELORUS SOUND Koituna R cem todentity what has caused change in TRACING THE SEDIMENT IN N PELORUS SOUND How did we find this out? Marborough District Council commissioned NWA to study the sediment sources in Te Hoiere Pelonus Sound using the latest scientific techniques This study enables better understanding of how human-induced and natural erosion sources have contributed to sediment composition and accumulation and identfies the sources of sediment deposited in the iver and a part of Te Hoiere/ Pelonus Sound disturbed the natural land cover De Mahau Soun. Researchers colected samples of soits and sediment from Sound are subsoil, stream bank erosion, dairy pasture. vers and the inner Te Hoiere Pelorus Sound. Sampling Included topsols, subsolis he soils beneath the topsoi, iver The proportions vary according to the location and streambank sediment, fine sediment deposits in river channels, sediment cores from Mahau Sound, and surtace aged in acale, from localed impacts on cockie beds due to different organic carbon biomarker. Samples were taken marine sediment tom the entrance to Te Hoiere Pelorus Sound (Chetwode lslands Nukuwaiata and Te Kakahoj. Key findings Sediment is one of the main threats to New Zealand's manine environment and has impacts on treshwater ecosystems. The Mahau Sound over the last century were estimated using two of sol from the land and its depostion in estuaries and the sea is a natural process, but the rate sediment is being deposited is higher than before human activities Sediment accumulation rates SA0 in Havelock Estuary and independent radioisotope dating methods. Pre historic SAR in the Mahau Sound were derived from radiocarbon dating of cockle shels. The shelifish remains preserved in cores trom one of three stes sampied in Mahau were aralysed along with The main contributors to sediment in Te Hoiere/Pelorus Sediment sources were traced using CSS (Compound Specific Stabie iIsotopej mehods. This method was developed by NWA scientists in the mid-2000s and is now uned across the world. The method identifies sols by their harvested pine and native forests The effects of increased sol erosion and sedimentation have early Maori activtes in Mahau Sound to extensive catchment om sstreamside, iverbed and seafioor deposits at various wide sol erosion and sedimentation since European settiement Goldmining, native forest clearance, pastoral farming and more recent agricutural and forestry activites have al let locations. These were compared to land-ute and natural reference samples. Ths enabled uns to determine what proportion of the samples were from which erosion sBource hatural or humaninduced. For more info on CSSI, see https://niwa.co.nz/essi The full technical neport can be found here: www.mariborough. govt.nalenvironmentcoastal sedimentation their legacy in the Marborough Sounds waters This study enabled us to understand the sources of sediment deposited on the verbed, on the riverbanks, and in the marine environment. The sources for each iver sampled are displayed above, and in percentage terms in the pie chars overleal. Sediment deposited on the riverbed: the major sources of deposited fine sediment dounstream in the rivers are stream-bank and subsols the soils beneath the topso Stream bank erosion is pronounced in the Katuna and Tinine, upper Ra and Whakamarino Wakamarina subcatchments Subsol erosion hotspots occur in the Tinline. Whakamarino and upper Ra subcatchments e. Tunakino, Opouri and Brown + Sedment deposited on the verbank dairy patture and harvested pine are subtartial sources of deposited fne sediment on verbarks Harvested pre topsol cortributions re highest at the outiets of the Upper Pelorus. Brown, Ronga and Kaluma (Opour subcatchments. Sheep pasture topsols make the largest contribution to ver sedment deposited near the outiet of the Katuna River, Contributions of topsols from native forest and kanuka senbto iver sediment deposits are unitormly low across all sampling stes in the Pelorus- Raand Katuna catchmens Sediment sources Maud Kenepunu Inlet 000 Kelbma Str Dveen Chariotte Sound Maho Sound Havelock Hoiere /Peloras R San n Oury p Wakamarina Fedmen ompncanet nd Sediment deposited in the marine environment pee overieaf 70% of sediment deposited over the last century in Mahau Sound is egacy sediment. This marine sediment is utmately composed of sol eroded trom the surrounding catchments as well as deposited marine organie mater jag phyloplanitor transported to Mahau Sound Compared with the preceding -2.000 years, the sediment accumlation rate over the 20th century s10 times hghe Lngyh d me which h ntag too hohg tonga kmpur ondyn aen w ngto -ea dondn anping looo lal M Thirty percent of the deposited sedment comes trom contermporary land uses over the past century ee overleat. Subsols are the largest contributor, followed by stream-bank erosion. Native forest and Mahau Sound sediment sources Next steps This report provides greater understanding of the sedment dynamics of Te HoierePelorus catchment. Sedimeont acoumulation rates are 10 times greater since European settement. Mean sediment source proportion (%) O 20 40 00 80 100 o 20 4o 00 80 100 0 20 40 00 80 100 Sediment has accumulated in, and circulates within the sound over time. Contermporary sediment loads add to mis historic sediment. 2013 2013 2016 The report also shows that the issues caused by deposited sedment have a long history There is a large amount of egacy sediment in the sound that wil continue to cause environmental issues for some time after the mitigation of contemporary sources of sediment. The Te Hoiere Restoration project is a community-led project focussed on neducing the 200 2008 2012 2001 2003 2008 amount of sediment and other contaminants entering the Pelorus Sound Te Hoiere. This report is an impotant part of understanding what the sources of these sediments and oontaminants may be 2000 For more information: Oliver Wade Envieonmental Scientist - Coastal Marborough District Council Oliver Wademariborough.govt.nz Phone: 03 s20 7400 1974 1978 MARLBOROUGH |DISTRICT COUNCIL 145 142 1948 1937 1828 121 121 NIWA Core MH-1 MH-2 MH3 Taihore Nukurangi Harvested Pine Kanuka MARINE Native Forest Soub-Pasture Sources of sediment acoumulating in Streambank Subaol Mahau Sound ner Pelorince e eaty 20n century determined trom CSS analysis of dated cores TRACING THE SEDIMENT IN PELORUS SOUND Koituna R