9 results for Hamilton, David P., Unclassified

  • LERNZ: Lake Ecosystem Restoration New Zealand – Fact Sheet

    Tempero, Grant Wayne; Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    Based at the University of Waikato (Figure 1), the aim of the LERNZ research programme is to provide end-users such as community groups, regional councils and governmental agencies with practical tools and expertise for restoring indigenous biodiversity and water quality in lakes. The research programme is centred around two main themes: • New models and technologies to effectively manage harmful algal blooms • New pest fish management and control technologies LERNZ is based at the University of Waikato, Hamilton New Zealand, and has established a number of collaborations with domestic and international research organisations since its inception in 2005.

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  • The contribution of lakes to greenhouse gas emissions – fact sheet

    Santoso, A; Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    Greenhouse gases such as carbon dioxide (C0₂) , methane (CH₄) and nitrous oxide (N₂0) trap heat in the atmosphere. Lakes can play an important role in regulating these gases at global scales. Total carbon uptake by lakes is of the same magnitude as that of oceans or forests, despite lakes occupying s area. In lakes, GHGs are mostly produced in the bottom sediment as products of organic matter decomposition. Geothermal activities - of importance to some Rotorua lakes - may also contribute substantial amounts of C0₂ and CH₄.

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  • Paleolimnology to determine lake reference conditions – fact sheet

    Kpodonu, A; Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    Paleolimnology is the study of the early history of lakes based on sediment composition. Lake sediments build up in undisturbed areas of lake bottoms (e.g. in deep central basins) over long periods of time. These sediments will reflect the prevailing conditions in the catchment, climate and in-lake processes at the time of deposition. Specific 'markers' can be used to determine when a particular layer of sediment was deposited. For example, in volcanic areas lakes sediments may contain volcanic ash layers from historical eruptions that can be used to date the sediment (Figure 1). Where it is possible to take long sediment cores in relatively undisturbed areas the historical record of the lake may stretch back far enough to give insights into historical climatic conditions and pre-human settlement state of the lake. This pre-human condition is sometimes referred to as a "reference state". Defining the reference state is important as it provides an indication of the extent to which the current state differs from it. This difference provides a useful reference point for setting targets to improve the state of a lake (e.g., as part of the limiting-setting process envisaged under the National Objectives Framework for Freshwater Management 2011).

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  • Catchment modelling with SWAT – fact sheet

    Me, W; Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    Catchment models determine the source and extent of water quality problems in a catchment. Catchment models may be used to identify 'hotspots' in a region and once calibrated these models may be used to test various land management, land use, and climate-change scenarios. SWAT (Soil & Water assessment tool) is a relatively complex model. The development of SWAT is a continuation of USDA Agricultural Research Service (ARS) modelling experience spanning more than 30 years. SWAT has been used with some degree of success by the LERNZ group at The University of Waikato and it has been applied to several New Zealand catchments. The model is capable of producing daily discharge and nutrient and sediment loads to streams at a sub-catchment level. ArcSWAT is an ArcGIS-ArcView extension and graphical user input interface for SWAT.

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  • Nutrient and sediment loads from farm drains – fact sheet

    Tempero, Grant Wayne; Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    Runoff from intensive agriculture has been identified as a major contributor to the decline of New Zealand's freshwater ecosystems. Excessive nutrient and sediment losses to lakes and rivers lead to reduced water clarity and quality, which in turn leads to reductions in biodiversity and amenity and aesthetic values.

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  • Applying citizen science to freshwater ecosystem restoration – fact sheet

    Peters, Michael A.; Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    Citizen science describes the diverse ways in which the public participates in scientific investigations. Participation covers a spectrum from sending observations to a project coordinator to designing, implementing protocols, analysing and sharing findings. The popularity of citizen science both for educational and scientific purposes has grown in recent decades. Community volunteers now participate in diverse programmes that investigate the effects of climate change on biota, evolutionary processes, invasive species ecology, and changes in water and air quality (Figure 1).

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  • Lake models – fact sheet

    Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    Models of lakes are used to provide insights into water quality at some future point in time, so that management actions may be targeted and cost-effective. In the past, small-scale physical models were used to simulate lake environments (Figure 1), but nowadays computer models are used to test potential management options. Computer models use a series of mathematical equations to describe the complex interactions amongst physical, chemical and biological processes that affect the water quality of a lake. The equations are stitched together consecutively in a computer program, allowing millions of calculations to take place in a single simulation.

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  • Lake restoration lags – fact sheet

    Mueller, H; Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    Regulatory responses to declines in lake health have often been characterised by long lag times. Under these circumstances regulation has often failed to prevent declining lake health or to implement successful restoration programmes. For Lake Rotorua, response lags can be seen in the time passing between the recognition of water quality decline (e.g. weed problems and algal blooms), and the effect of regulatory actions to improve water quality (e.g. land use management changes). Research undertaken by Mueller et al. (2015) has shown that lag times of approximately 5 years may occur between significant environmental declines and regulatory responses.

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  • LakeAnalyzer: Lake internal dynamics analysis software – fact sheet

    Muraoka, Kohji; Hamilton, David P. (2015)

    Unclassified
    University of Waikato

    LakeAnalyzer is a computer program used to calculate indices of mixing and stratification, which are critical to understanding biogeochemical cycles of lakes and reservoirs. Lake physical stability indices, surface mixing depth and thermocline depth are calculated according to established literature definitions and returned to the user in a time-series format. LakeAnalyzer was developed to analyse high-frequency data collected from instrumented lake buoys (Figure 1). It provides a way to compare mixing and stratification indices in lakes across gradients of climate, hydrophysiography, and time, and provides a basis for understanding of the resulting biogeochemical transformations at different spatial and temporal scales.

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