title: Catchment and lake water quality modelling to assess management options for Lake Rerewhakaaitu

authors: Cho, Eunju

abstract: Lake Rerewhakaaitu in the Bay of Plenty Region of North Island, has one of the most intensively farmed lake catchments in New Zealand. Nitrate concentrations in two surface stream inflows to the lake show substantial and statistically significant increases, between 1995 and 2015, however, lake water quality has remained relatively stable. The lake is polymictic (i.e., it mixes frequently) and is partly perched, with an effective hydrological catchment of approximately 10% of the surface topographic catchment. We used the hydrodynamic-ecological model DYRESM-CAEDYM to examine the relationship between inflow quantity and quality, and lake water quality. A groundwater model (MODFLOW) provided groundwater discharge values from the hydrologically effective catchment, to the lake model (DYRESM-CAEDYM). The model successfully reproduced the magnitude and dynamics of field measurements, as evidenced by low statistical error. Based on a novel uncertainty analysis that allows for assessment of forcing factors that contribute to model error, a component of the statistical error was identified to be due to lake water level variations, which was attributed to ecological changes in the littoral (shallow-water) zone of the lake. The calibrated model was used with a set of scenarios to examine land use change within the effective hydrological catchment, as well as climate change. Establishment of the lake model was subject to several areas of substantial uncertainty, including derivation of stream inflows by statistical modelling (rather than direct observation), hydrological uncertainty with regard to drainage pathways in the lake catchment, and reliability of some nutrient measurements in the lake and streams. Nevertheless, the present model can be considered among the most sophisticated tools available with which to inform lake management decisions. Model results suggest that improved land management efforts within the wider topographic catchment will have only minor impacts on Lake Rerewhakaaitu water quality, but within the hydrologically effective catchment land use improvements to decrease losses of nitrogen and phosphorus to the lake will be important. Maintaining and/or enhancing the forested area within the hydrologically effective catchment and potentially retiring (to indigenous vegetation) some of the area, as well as maintaining the riparian buffer of the lake, will help to maintain water quality of Lake Rerewhakaaitu. The model predicted that a future warmer climate would likely increase the duration of temperature stratification in the water column, leading to more deoxygenation of bottom waters and a decline in water quality. Offsetting this with maintaining and enhancing vegetation in the riparian area and hydrologically effective catchment may help to offset these effects.

text: Catchment and lake water quality modelling to assess management options for Lake Rerewhakaaitu Lake Rerewhakaaitu in the Bay of Plenty Region of North Island, has one of the most intensively farmed lake catchments in New Zealand. Nitrate concentrations in two surface stream inflows to the lake show substantial and statistically significant increases, between 1995 and 2015, however, lake water quality has remained relatively stable. The lake is polymictic (i.e., it mixes frequently) and is partly perched, with an effective hydrological catchment of approximately 10% of the surface topographic catchment. We used the hydrodynamic-ecological model DYRESM-CAEDYM to examine the relationship between inflow quantity and quality, and lake water quality. A groundwater model (MODFLOW) provided groundwater discharge values from the hydrologically effective catchment, to the lake model (DYRESM-CAEDYM). The model successfully reproduced the magnitude and dynamics of field measurements, as evidenced by low statistical error. Based on a novel uncertainty analysis that allows for assessment of forcing factors that contribute to model error, a component of the statistical error was identified to be due to lake water level variations, which was attributed to ecological changes in the littoral (shallow-water) zone of the lake. The calibrated model was used with a set of scenarios to examine land use change within the effective hydrological catchment, as well as climate change. Establishment of the lake model was subject to several areas of substantial uncertainty, including derivation of stream inflows by statistical modelling (rather than direct observation), hydrological uncertainty with regard to drainage pathways in the lake catchment, and reliability of some nutrient measurements in the lake and streams. Nevertheless, the present model can be considered among the most sophisticated tools available with which to inform lake management decisions. Model results suggest that improved land management efforts within the wider topographic catchment will have only minor impacts on Lake Rerewhakaaitu water quality, but within the hydrologically effective catchment land use improvements to decrease losses of nitrogen and phosphorus to the lake will be important. Maintaining and/or enhancing the forested area within the hydrologically effective catchment and potentially retiring (to indigenous vegetation) some of the area, as well as maintaining the riparian buffer of the lake, will help to maintain water quality of Lake Rerewhakaaitu. The model predicted that a future warmer climate would likely increase the duration of temperature stratification in the water column, leading to more deoxygenation of bottom waters and a decline in water quality. Offsetting this with maintaining and enhancing vegetation in the riparian area and hydrologically effective catchment may help to offset these effects.

year: 2020

title: Compression and explanation using hierarchical grammars

authors: Nevill-Manning, Craig G.

subjects: computer science

abstract: Data compression is an eminently pragmatic pursuit: by removing redundancy, storage can be utilised more efficiently. Identifying redundancy also serves a less prosaic purpose-it provides cues for detecting structure, and the recognition of structure coincides with one of the goals of artificial intelligence: to make sense of the world by algorithmic means. This paper describes an algorithm that excels at both data compression and structural inference. This algorithm is implemented in a system call SEQUITUR that efficiently deals with sequences containing millions of symbols.

text: Compression and explanation using hierarchical grammars Data compression is an eminently pragmatic pursuit: by removing redundancy, storage can be utilised more efficiently. Identifying redundancy also serves a less prosaic purpose-it provides cues for detecting structure, and the recognition of structure coincides with one of the goals of artificial intelligence: to make sense of the world by algorithmic means. This paper describes an algorithm that excels at both data compression and structural inference. This algorithm is implemented in a system call SEQUITUR that efficiently deals with sequences containing millions of symbols.

year: 1996-07

title: Te Mata Ono. E tipu atu te kūmara, e ohu mai te anuhe

authors: Pēwhairangi, Te Aorere Tūwhakairiora

subjects: Māori television

abstract: Mai anō, mai anō kua whakapaoho te iwi Māori, tīmata mai ai i te mahi whaikōrero, i te mahi karanga, i te mahi taonga puoro, i te mahi toi, me te mahi waiata. Ko ngā mahi nei he huarahi tuku karere i tētahi takitahi, takitini rānei ki tētahi takitahi, takitini rānei. Mā ēnei mahi e whakawhitiwhiti mōhiohio ai te tangata. Nō te taitanga mai a te Pākehā kua whai huarahi whakapaoho atu anō te iwi Māori i ō rātau mōhiohio, tīmata ana mai i ngā niu pepa, eke ana rā ki ngā reo irirangi, tae noa mai ki te pouaka whakaata me te ipurangi. Ko te rangahautanga nei ka titiro ki tētahi o ngā huarahi mātāmuri e whakapaohotia ai ngā mōhiohio a te Māori, arā te pouaka whakaata. Ka arotaketia ngā mahi tuari mōhiohio a te whare waihanga hōtaka pouaka whakaata nei a Whakaata Māori mā tētahi anga tātai e kīia nei ko Te Mata Ono.

I ngā tau 15 kua pahure ake nei ehara i te mea kua tū a Whakaata Māori hai kaitohatoha mōhiohio Māori, engari hai kaiwhakarauora hoki i te reo Māori me ngā tikanga Māori. I te tuhinga roa nei ka tirohia ngā huarahi taketake me ngā huarahi hōu o te whakapaoho i ngā mōhiohio o te tangata mā roto i a Whakaata Māori. Mā te whakauruuru i ngā huarahi e rua nei e whakahōuhia ai te ara, e whakapaoho Māoritia ai hoki ngā hōtaka o te wā. 

E ono katoa ngā āhuatanga o te anga e kōrerotia nei. Ko te tuhinga roa nei he haurua o te anga. Nā ngā ture ā-kupu o te tohu paerua nei, ka rangahaua rētōtia e a au ngā wāhanga e toru o te ono e kīia nei ko Te Mata Ako, Te Mata Tikanga, Te Mata Iwi anō hoki. E tuhia ana hoki tētahi atu tuhinga roa i te wā nei e Kimiora Kaire-Melbourne. Kai te titiro ia ki ērā atu wāhanga e toru o te anga, Te Mata Māori, Te Mata Pākehā me Te Mata ō-Tua. Hai te mutunga o ngā tuhinga roa e rua nei, ka whakapiria ai ngā āhuatanga e ono kia waihanga pūmautia ai te anga tātari o Te Mata Ono. Ka piri ana te anga tātari ko te whāinga kia whakahāngaitia ai ki a Whakaata Māori hai tautoko, hai hāpai, hai ārahi hoki i te teihanga ki ngā rā kai te heke mai.

text: Te Mata Ono. E tipu atu te kūmara, e ohu mai te anuhe Mai anō, mai anō kua whakapaoho te iwi Māori, tīmata mai ai i te mahi whaikōrero, i te mahi karanga, i te mahi taonga puoro, i te mahi toi, me te mahi waiata. Ko ngā mahi nei he huarahi tuku karere i tētahi takitahi, takitini rānei ki tētahi takitahi, takitini rānei. Mā ēnei mahi e whakawhitiwhiti mōhiohio ai te tangata. Nō te taitanga mai a te Pākehā kua whai huarahi whakapaoho atu anō te iwi Māori i ō rātau mōhiohio, tīmata ana mai i ngā niu pepa, eke ana rā ki ngā reo irirangi, tae noa mai ki te pouaka whakaata me te ipurangi. Ko te rangahautanga nei ka titiro ki tētahi o ngā huarahi mātāmuri e whakapaohotia ai ngā mōhiohio a te Māori, arā te pouaka whakaata. Ka arotaketia ngā mahi tuari mōhiohio a te whare waihanga hōtaka pouaka whakaata nei a Whakaata Māori mā tētahi anga tātai e kīia nei ko Te Mata Ono.

I ngā tau 15 kua pahure ake nei ehara i te mea kua tū a Whakaata Māori hai kaitohatoha mōhiohio Māori, engari hai kaiwhakarauora hoki i te reo Māori me ngā tikanga Māori. I te tuhinga roa nei ka tirohia ngā huarahi taketake me ngā huarahi hōu o te whakapaoho i ngā mōhiohio o te tangata mā roto i a Whakaata Māori. Mā te whakauruuru i ngā huarahi e rua nei e whakahōuhia ai te ara, e whakapaoho Māoritia ai hoki ngā hōtaka o te wā. 

E ono katoa ngā āhuatanga o te anga e kōrerotia nei. Ko te tuhinga roa nei he haurua o te anga. Nā ngā ture ā-kupu o te tohu paerua nei, ka rangahaua rētōtia e a au ngā wāhanga e toru o te ono e kīia nei ko Te Mata Ako, Te Mata Tikanga, Te Mata Iwi anō hoki. E tuhia ana hoki tētahi atu tuhinga roa i te wā nei e Kimiora Kaire-Melbourne. Kai te titiro ia ki ērā atu wāhanga e toru o te anga, Te Mata Māori, Te Mata Pākehā me Te Mata ō-Tua. Hai te mutunga o ngā tuhinga roa e rua nei, ka whakapiria ai ngā āhuatanga e ono kia waihanga pūmautia ai te anga tātari o Te Mata Ono. Ka piri ana te anga tātari ko te whāinga kia whakahāngaitia ai ki a Whakaata Māori hai tautoko, hai hāpai, hai ārahi hoki i te teihanga ki ngā rā kai te heke mai.

year: 2019