title: Simulating discharge and pollutants from the Waipa Stream catchment under different irrigation scenarios using the SAWT model

authors: Me, Wang

abstract: The water quality of Lake Rotorua has declined over several decades due to increasing inputs of nitrogen (N) and phosphorus (P). Prior to 1991, the Rotorua City wastewater treatment plant was a significant contributor to this decline through direct discharge of treated municipal wastewater to the lake. In 1991 the Rotorua Lakes Council (RLC) halted wastewater discharge to Lake Rotorua and commenced land disposal of treated wastewater by spay irrigation to 193 ha of the Whakarewarewa Forest. It was intended that plant uptake and microbial denitrification would reduce N levels, and P would be removed through absorption and retention to clay soil particles. The aim was to reduce wastewater nutrient loads to the point that wastewater runoff entering the Waipa Stream, and ultimately Lake Rotorua, would have a minimal impact on the trophic state of Lake Rotorua.
Resource consent conditions for wastewater disposal to the Whakarewarewa Forest restricted total nitrogen (TN) and total phosphorus (TP) wastewater losses to the Waipa Stream to 30 tonnes yr⁻¹ and 3 tonnes yr⁻¹, respectively. Previous assessments of nutrient losses have indicated some non-compliance with the TN consent limit, there has also been an increase in TP loading to the Waipa Stream since 2002. These increases may be caused by a number of factors including the application rate of wastewater, increases in the nutrient load from non-irrigated areas within the catchment, forest operations not associated with wastewater irrigation and altered rainfall patterns. The Rotorua Lakes Council contracted the University of Waikato to provide an assessment of possible causes for the increased nutrient loading, and to investigate how varying the timing of wastewater irrigation regimes could affect nutrient loading to the Waipa Stream.
The Soil and Water Assessment Tool (SWAT) is a GIS based catchment model used to simulate water fluxes and contaminant transport. The model was parameterised using hydrological and water quality values from relevant literature, and values derived from model auto-calibration within fixed ranges using a Sequential Uncertainty Fitting (SUFI-2) procedure followed by manual adjustment. Model results showed a high correspondence (r > 0.8; p < 0.001) between measurements and simulations of discharge. However, the model underestimated several peaks of weekly mean TSS load during high rainfall events which were found to be related to harvesting of forest blocks. Underestimates of weekly mean TP peaks were also observed and appeared to be either a lagged response to high rainfall, high TP concentrations in the irrigated wastewater or harvesting of several forest blocks concurrently. Most peaks in hourly routing of NO₃-N and TN loads averaged to weekly time scale also corresponded to high rainfall as well as to high TN concentrations in the wastewater.
The effects of various wastewater irrigation scenarios on downstream water quality were also simulated using SWAT. Daily wastewater irrigation was the most effective scenario for reducing nutrient leaching and avoiding soil nutrient saturation when compared to weekly irrigation (i.e., identical total volume on a weekly basis). Cessation of irrigation on high rainfall days, with reassignment of the irrigation to the first subsequent low-rainfall day, produced unexpected small increases in annual TP (+5%) and TN loading (+2.5%). Simulations of increased area of irrigation or ceasing irrigation resulted in reductions of nutrient loads to the Waipa Stream.
These results indicate that harvesting of plantation forest blocks in the Waipa sub-catchment and wastewater irrigation during high rainfall were contributing to higher than estimated TSS and TP loading to the Waipa Stream. Modelling of variations in wastewater irrigation frequency showed that reductions in TP and TN loadings to the Waipa Stream could be achieved by switching to a programme of daily rather than weekly irrigation and avoidance of irrigation during or the day following heavy rainfall. These findings support the decision to switch irrigation frequency from weekly to daily and are likely to assist in reducing the impact of anthropogenic nutrient loading on Lake Rotorua.

text: Simulating discharge and pollutants from the Waipa Stream catchment under different irrigation scenarios using the SAWT model The water quality of Lake Rotorua has declined over several decades due to increasing inputs of nitrogen (N) and phosphorus (P). Prior to 1991, the Rotorua City wastewater treatment plant was a significant contributor to this decline through direct discharge of treated municipal wastewater to the lake. In 1991 the Rotorua Lakes Council (RLC) halted wastewater discharge to Lake Rotorua and commenced land disposal of treated wastewater by spay irrigation to 193 ha of the Whakarewarewa Forest. It was intended that plant uptake and microbial denitrification would reduce N levels, and P would be removed through absorption and retention to clay soil particles. The aim was to reduce wastewater nutrient loads to the point that wastewater runoff entering the Waipa Stream, and ultimately Lake Rotorua, would have a minimal impact on the trophic state of Lake Rotorua.
Resource consent conditions for wastewater disposal to the Whakarewarewa Forest restricted total nitrogen (TN) and total phosphorus (TP) wastewater losses to the Waipa Stream to 30 tonnes yr⁻¹ and 3 tonnes yr⁻¹, respectively. Previous assessments of nutrient losses have indicated some non-compliance with the TN consent limit, there has also been an increase in TP loading to the Waipa Stream since 2002. These increases may be caused by a number of factors including the application rate of wastewater, increases in the nutrient load from non-irrigated areas within the catchment, forest operations not associated with wastewater irrigation and altered rainfall patterns. The Rotorua Lakes Council contracted the University of Waikato to provide an assessment of possible causes for the increased nutrient loading, and to investigate how varying the timing of wastewater irrigation regimes could affect nutrient loading to the Waipa Stream.
The Soil and Water Assessment Tool (SWAT) is a GIS based catchment model used to simulate water fluxes and contaminant transport. The model was parameterised using hydrological and water quality values from relevant literature, and values derived from model auto-calibration within fixed ranges using a Sequential Uncertainty Fitting (SUFI-2) procedure followed by manual adjustment. Model results showed a high correspondence (r > 0.8; p < 0.001) between measurements and simulations of discharge. However, the model underestimated several peaks of weekly mean TSS load during high rainfall events which were found to be related to harvesting of forest blocks. Underestimates of weekly mean TP peaks were also observed and appeared to be either a lagged response to high rainfall, high TP concentrations in the irrigated wastewater or harvesting of several forest blocks concurrently. Most peaks in hourly routing of NO₃-N and TN loads averaged to weekly time scale also corresponded to high rainfall as well as to high TN concentrations in the wastewater.
The effects of various wastewater irrigation scenarios on downstream water quality were also simulated using SWAT. Daily wastewater irrigation was the most effective scenario for reducing nutrient leaching and avoiding soil nutrient saturation when compared to weekly irrigation (i.e., identical total volume on a weekly basis). Cessation of irrigation on high rainfall days, with reassignment of the irrigation to the first subsequent low-rainfall day, produced unexpected small increases in annual TP (+5%) and TN loading (+2.5%). Simulations of increased area of irrigation or ceasing irrigation resulted in reductions of nutrient loads to the Waipa Stream.
These results indicate that harvesting of plantation forest blocks in the Waipa sub-catchment and wastewater irrigation during high rainfall were contributing to higher than estimated TSS and TP loading to the Waipa Stream. Modelling of variations in wastewater irrigation frequency showed that reductions in TP and TN loadings to the Waipa Stream could be achieved by switching to a programme of daily rather than weekly irrigation and avoidance of irrigation during or the day following heavy rainfall. These findings support the decision to switch irrigation frequency from weekly to daily and are likely to assist in reducing the impact of anthropogenic nutrient loading on Lake Rotorua.

year: 2017

title: Taiwanese textbooks for young learners of English: A criterion-referenced analysis

authors: Wang, Wei Pei

subjects: Taiwan

abstract: This article focuses on one of the problems faced by one Pacific rim country, Taiwan, in coming to terms with the increasing globalization of English, that is, the production of textbooks that are appropriate for young learners. Increasing pressure to ensure that its citizens achieve a high level of proficiency in English has led Taiwan, in common with many other countries, to reduce the age at which children are introduced to English in schools. This has lead to the proliferation of English textbooks for young learners. The Taiwan national English curriculum guidelines recommend that teaching materials should cultivate communicative ability and should include varied activities, a range of different types of text, and interesting, practical and lively topics and themes. Three textbook series produced in Taiwan are analyzed and discussed here in terms of a range of effectiveness criteria. It is concluded that the textbook writers have not yet come to terms with the recommendations in the English curriculum guidelines. In that these recommendations are similar to recommendations included in national curriculum guidelines for the teaching of languages in many other parts of the world, it is suggested that language teaching materials produced elsewhere might usefully be analyzed in a similar way.

text: Taiwanese textbooks for young learners of English: A criterion-referenced analysis This article focuses on one of the problems faced by one Pacific rim country, Taiwan, in coming to terms with the increasing globalization of English, that is, the production of textbooks that are appropriate for young learners. Increasing pressure to ensure that its citizens achieve a high level of proficiency in English has led Taiwan, in common with many other countries, to reduce the age at which children are introduced to English in schools. This has lead to the proliferation of English textbooks for young learners. The Taiwan national English curriculum guidelines recommend that teaching materials should cultivate communicative ability and should include varied activities, a range of different types of text, and interesting, practical and lively topics and themes. Three textbook series produced in Taiwan are analyzed and discussed here in terms of a range of effectiveness criteria. It is concluded that the textbook writers have not yet come to terms with the recommendations in the English curriculum guidelines. In that these recommendations are similar to recommendations included in national curriculum guidelines for the teaching of languages in many other parts of the world, it is suggested that language teaching materials produced elsewhere might usefully be analyzed in a similar way.

year: 2007-02

title: A trans-national analysis of equitable utilisation and minimisation of environmental harm under environmental laws at international, federal and national levels

authors: Hasan, Qaraman

subjects: International Environmental Law

abstract: Due to increasing demand for various human needs and climate change issues, rivers are now under enormous pressure. With increasing pressure on these valuable natural resources, responses among state and non-state actors are insufficient in the Anthropocene. To fill the gap, International Environmental Law (IEL) provides several principles for better management of these resources. Equitable utilisation and minimisation of environmental harm are among the most important principles of the IEL. From a theoretical perspective, these principles should lead to the sustainability of these resources and promote cooperation among relevant actors.

However, many river basins are still not allocated equitably and suffer from environmental damage. By using comparative, doctrinal, and empirical research methods, this thesis evaluates the two principles at the international level in Tigris and Euphrates River Basin, the federal level in Murray Darling Basin and at the local level in the Waikato River catchment. The research discovered major challenges for implementing the two principles. One major challenge is sovereignty, another is a lack or weakness of local voices and transparency. As the nature and status of all basins are different, the challenges are not exactly the same. For example, hearing local voices and better information transparency have significantly improved in the Waikato River.

As the challenges for implementing the two principles are not purely legal, the responses should blend legal solutions with political and socio-economic solutions. Therefore, this thesis strongly supports shared sovereignty among states at the international level as well as shared sovereignty with indigenous and minority groups at the national level. Cooperation among national and international actors in the river basins is also crucial for implementing the two principles effectively. Finally, there is the opportunity to establish basin institutions or organisations to manage river basins integrated and sustainable. This is vital in the case of TE-RB because the basin still lacks an institution. Furthermore, the basin institution in the MDB requires more robust compliance and monitoring power because the provisions of the Water Act 2007 and the basin plan still have not been implemented effectively.

Finally, the thesis concludes with two common lessons in comparing these cases. The first lesson is that equitable utilisation cannot be implemented effectively if it is not accepted by the local community in a broad and deep meaning. It means that the equitable allocation should be extended from only the riparian states to equitable allocation among the people within each state. The second lesson is that the minimisation of environmental harm cannot be implemented without determining the minimum flow of rivers, particularly transboundary rivers. Determining an environmental impact assessment for water projects and taking advantage of available solutions of nature contributes significantly in implementing the two principles and sustainable management of our rivers.

text: A trans-national analysis of equitable utilisation and minimisation of environmental harm under environmental laws at international, federal and national levels Due to increasing demand for various human needs and climate change issues, rivers are now under enormous pressure. With increasing pressure on these valuable natural resources, responses among state and non-state actors are insufficient in the Anthropocene. To fill the gap, International Environmental Law (IEL) provides several principles for better management of these resources. Equitable utilisation and minimisation of environmental harm are among the most important principles of the IEL. From a theoretical perspective, these principles should lead to the sustainability of these resources and promote cooperation among relevant actors.

However, many river basins are still not allocated equitably and suffer from environmental damage. By using comparative, doctrinal, and empirical research methods, this thesis evaluates the two principles at the international level in Tigris and Euphrates River Basin, the federal level in Murray Darling Basin and at the local level in the Waikato River catchment. The research discovered major challenges for implementing the two principles. One major challenge is sovereignty, another is a lack or weakness of local voices and transparency. As the nature and status of all basins are different, the challenges are not exactly the same. For example, hearing local voices and better information transparency have significantly improved in the Waikato River.

As the challenges for implementing the two principles are not purely legal, the responses should blend legal solutions with political and socio-economic solutions. Therefore, this thesis strongly supports shared sovereignty among states at the international level as well as shared sovereignty with indigenous and minority groups at the national level. Cooperation among national and international actors in the river basins is also crucial for implementing the two principles effectively. Finally, there is the opportunity to establish basin institutions or organisations to manage river basins integrated and sustainable. This is vital in the case of TE-RB because the basin still lacks an institution. Furthermore, the basin institution in the MDB requires more robust compliance and monitoring power because the provisions of the Water Act 2007 and the basin plan still have not been implemented effectively.

Finally, the thesis concludes with two common lessons in comparing these cases. The first lesson is that equitable utilisation cannot be implemented effectively if it is not accepted by the local community in a broad and deep meaning. It means that the equitable allocation should be extended from only the riparian states to equitable allocation among the people within each state. The second lesson is that the minimisation of environmental harm cannot be implemented without determining the minimum flow of rivers, particularly transboundary rivers. Determining an environmental impact assessment for water projects and taking advantage of available solutions of nature contributes significantly in implementing the two principles and sustainable management of our rivers.

year: 2023