The Problem of Scale in Indigenous Knowledge: a Perspective from Northern Australia

Over the last decade, indigenous knowledge has been widely touted by researchers and natural resource managers as a valuable contributor to natural resource management and biodiversity conservation. In Australia, the concept of indigenous knowledge has gained such rapid currency that it has tended toward an essentialized and universal truth rather than remaining a diverse range of highly localized and contested knowledge. In this paper, I undertake a critical analysis of some of the current issues around the interpretation and application of indigenous knowledge and its relationship with natural resource management in northern Australia. Through a focus on how indigenous knowledge operates at a range of scales, I argue that indigenous knowledge is not adapted to the scales and kinds of disturbances that contemporary society is exerting on natural systems. Rather than being realistic about the limitations of indigenous knowledge, I argue that nonindigenous interpretations of indigenous knowledge have propelled us toward reified meanings, abstracted concepts, and an information-based taxonomy of place. The result can be the diminishing and ossifying of a dynamic living practice and the failure to recognize expressions of indigeneity in contemporary forms

Detecting the cause of change using uncertain data: Natural and anthropogenic factors contributing to declining groundwater levels and flows of the Wairau Plain aquifer, New Zealand

1 Study Region: The unconfined Wairau Aquifer in the Marlborough District of New Zealand is almost exclusively recharged by the Wairau River and serves as the major resource for drinking water and irrigation in the region. A declining trend in aquifer levels and low-land spring flows has been observed for the past decades. 2 Study Focus: The aim of this study is to identify and analyse natural and anthropogenic factors controlling the hydrological regime of the Wairau Aquifer. Concurrent trends in the long-term water balance components for the Wairau catchment and in low-flow statistics as well as the correlation between hydro-meteorological drivers and the Interdecadal Pacific Oscillation (IPO) index were investigated. The impact of river morphology changes on river recharge rates was studied using a previously developed groundwater flow model. 3 New Hydrological Insights for the Region: Our study found that long-term trends in declining catchment-scale precipitation are superimposed on climate oscillation and a strong annual variability. Jointly, these processes have resulted in lower than average river flows, increased low-flow periods, and consequently in lower rates of aquifer recharge. River engineering caused erosion of the braided river morphology, leading to a possibly permanent loss of aquifer storage. Groundwater abstraction is not accurately known which is a limitation of this study. This additional information and adaptation strategies are required for sustainable management of the groundwater resources

Corrigendum to “Palaeohydrogeology and Transport Parameters Derived from 4He and Cl Profiles in Aquitard Pore Waters in a Large Multilayer Aquifer System, Central Australia”

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.In the article titled “Palaeohydrogeology and Transport Parameters Derived from 4 He and Cl Profiles in Aquitard Pore Waters in a Large Multilayer Aquifer System, Central Australia” [1], Mr. Stanley D. Smith was missing from the authors’ list. Mr. Stanley made a significant contribution in helping with the core sampling protocol, canister leak testing, and discussing modelling methods. The corrected authors’ list is shown above

Does vadose zone flow forecasting depend on the type of calibration data?

Unsaturated subsurface water flow is often described by a flow model which is calibrated on either observed soil water content or tensiometric pressure head measurements. For a given model structure the calibration on one data type may lead to significant errors in predictions of the other data type. These errors are difficult to quantify since simultaneous measurements of pressure head and water content are generally not available. Independent vadose zone data of both types were recorded at an intensively investigated experimental field site in the Lake Taupo catchment, New Zealand. A numerical flow model was set up and calibrated (i) using tensiometric pressure head observations, (ii) using soil water content (TDR) observations, and (iii) using both tensiometric and TDR data. The global multi-method search algorithm AMALGAM was used to estimate five soil hydraulic parameters in five model layers, totaling 25 optimized parameters. In the cases (i) and (ii), a single aggregated objective function was defined to fit measurements from four different depths in the vadose zone profile. The third model calibration was placed in a multi-objective context to include the two different data types simultaneously. The trade-off pattern between the fit to the water content and pressure head observations was investigated. Parameter sets from the three calibrations were then used for predicting pressure heads and water content in the vadose zone for independent data, not previously used in the calibration process. The results suggest that predictions of tensiometric pressure head and volumetric water content significantly depend on the type of data used for model calibration. Large differences in the model predictions occur when calibrating to one data type and predicting the other. This demonstrates the need to inform the model about the required prediction data type in the calibration process. This is a prerequisite to make reliable forecasts of vadose zone water flow and to determine realistic uncertainty bounds in vadose zone flow modeling

Natural and anthropogenic factors controlling the hydrological regime of the Wairau Plain Aquifer, New Zealand

The Wairau River is situated in the Marlborough Region in the North of New Zealand’s South Island. Near its mouth into the Pacific Ocean, the river is recharging a regionally important aquifer which is managed for drinking water production in the Blenheim region and for irrigation of New Zealand’s largest wine growing area. The Wairau Plain Aquifer is almost exclusively recharged by the Wairau River and closely related to its hydrological regime. The groundwater levels and spring flows at the Wairau Plain Aquifer have shown progressive decline in the past decades. This study analyses potential factors to explain this trend and a change in the hydrological regime using a combination of field investigations and a detailed numerical flow model. Results indicate that the driving forces of the system, rainfall and runoff, exhibit not only a strong interannual variability but seem to be also correlated with longer climate oscillations. The groundwater storage is also affected by strong seasonal variations and is particularly vulnerable to the frequency and duration of low-flow periods in summer. Climate variability alone, however, does not explain the log-term trends in storage. Another factor is the erosion of the Wairau River bed which can lead to a permanent loss of storage capacity and is caused by the effects of river training but also by extreme flood events. Another factor that should be taken into consideration is groundwater abstraction for irrigation, which accounts only for 1% of the total estimated storage, but up to 20% of the “live” manageable storage. The better understanding of the mechanisms and factors controlling the Wairau Plain Aquifer contributes to the identification of adaptation strategies for a sustainable management of the groundwater resources

How to save a rock star from extinction

The charismatic and highly mobile Carnaby’s Black-Cockatoo is regarded as the ‘Rock Star’ of the Australian bird world. It now classified in WA as ‘rare or likely to become extinct’ and federally listed as Endangered. The last 50 years has seen a 50% decline in their population, and their range has been reduced by up to one-third. It is one of three black cockatoos found in southwest Western Australia. The others are Baudin’s Black-Cockatoo and a subspecies of the Red-tailed Black-Cockatoo. These birds are endemic to the South West region of Western Australia, meaning that they are found nowhere else in the world. All three are threatened. Because cockatoos are long-lived birds (up to 50 years) and they raise few chicks to adulthood, it is highly likely that the birds we see today are an ageing population. So what happens when this highly mobile species faces a ‘perfect storm’ of threats from urban sprawl, clearing of nesting and roosting habitat and even its last refugia, an introduced species of pine, is being logged. Is its immenent extinction a failure of policy by State and Commonwealth governments? Marc Wohling speaks to Samantha Vine and Dr Jess Lee from Birdlife Australia to find out. If you would like to donate to the Black Cockatoo Recovery Project go to the Birdlife Australia link

Wairau River-Wairau Aquifer Interaction

This report presents initial findings from an investigation into understanding the nature of transient recharge from the Wairau River to the Wairau Aquifer. This investigation has been a year-long collaboration between Marlborough District Council (MDC), the Water & Earth System Science Competence Cluster (WESS) at University of Tübingen in Germany, and Lincoln Agritech. The intention of this phase of the Wairau Aquifer recharge project is twofold: To review our conceptual understanding of the river and aquifer, and identify knowledge gaps; To develop a numerical model to quantify the river-aquifer exchange based on that conceptual understanding . Historical flow gauging data shows that approximately 7.5 m³/s is recharged from the river to the Wairau Aquifer between Rock Ferry and Wratts Road at flows less than 20 m³/s. Temporary flow sites have been established at Rock Ferry, SH6 and Wratts Road, and a good flow-rating curve has been established at Rock Ferry. The difference between flows at Rock Ferry and SH1 indicates that aquifer recharge increases as the river flow increases. The preliminary evidence suggests that 15 m³/s or more may be lost as recharge pulses during high flow events, although further work is required to correct flow for time lags in the river which will improve these estimates. One of the key findings of this report is that the river appears to be perched above the Wairau Aquifer across its main recharge reach. This means that there is a vertical hydraulic gradient between the river and aquifer where most of the recharge occurs, which theoretically simplifies the calculation for estimating transient recharge rates. Another key finding is that the hydraulic nature of the aquifer is more complex than our previous simple unconfined aquifer conceptual model. Groundwater monitoring records and aquifer test data indicate that the aquifer is highly stratified. This stratification explains the observation that the aquifer may be perched. The reason for this is that a strong vertical to horizontal anisotropy in permeability enables groundwater to potentially drain faster than it can be recharged by the river. There is also the possibility of distinct upper and lower aquifer horizons, although this needs to be explored further. The implication of aquifer stratification for estimating river recharge is that the groundwater monitoring sites are representative of quite localised conditions. Therefore, for the prediction of recharge rates, groundwater data can be used to constrain hydraulic parameters within our numerical model, but it is preferable to calculate recharge rates based on river observations rather than changes in groundwater levels at a particular site. Furthermore, if the is indeed river perched over its main recharge reach, as the available evidence suggests, the prediction of transient recharge rates will be largely determined by river geometry, and the relationship between stage and wetted river bed perimeter. A steady state numerical model has been built and calibrated to accord with our conceptual understanding. A combination of groundwater level observations and surface water fluxes were used for calibration targets. The best-fit "compromise" solution resulted in data fits that are well within the measurement uncertainty ranges. One of the key findings of the model was that the river was required to be perched to enable calibration, which supports field evidence outlined in this report. Further work for 2015 will involve a more intensive field program to improve our understanding of the relationship between river flows and groundwater levels immediately adjacent to and beneath the river. Transient calibration of the numerical model will also begin, and we intend to use the final calibrated model to estimate transient aquifer recharge rates.Marlborough District Counci

Wairau Aquifer recharge pathways

The Wairau Aquifer is almost entirely river-recharged, although the distribution of recharge groundwater flow paths is poorly constrained. To improve conceptualisation and inform numerical flow modelling, the stratigraphy of the Holocene alluvial fan was reviewed. Previous authors have noted subtle variability within the gravel assemblage. Our aim was to identify spatial patterns of deposition informed by climate-mediated changes in the energy of the river environment. We used a three-stage process: an initial scan of deep well logs, 3D visualisation using GMS software, and a final refinement by plotting intercepts of distinctive facies in GIS. Drillers’ well logs were referred to throughout this approach. The lithologies were lumped into four depositional environments, from high-energy (proximal channel gravels) to low-energy (distal overbank flow). Lithological information was supplemented by qualitative comments made by the drillers on the water-bearing nature of the sediments encountered. The alluvial fan consists of upper and lower members which are separated by low-permeability matrix-supported gravel. The upper member shows lateral facies changes which have distinct hydraulics properties. Three areas for preferential recharge can be recognized: 1) 35% via a 3km reach in the fan apex where lower member is in contact with the active river channel gravels. 2) 20% via a shallow historical overbank flow channel. 3) 45% via a 3–4km reach in the fan toe where the river traverses a thickening high-permeability upper member gravels. Recharge from this reach provides a shallow groundwater pathway to downgradient springs

Fate of a dairy cow urine pulse in a layered volcanic vadose zone

Nitrate-N leaching from dairy cow urine patches has been identified as one of the major contributors to groundwater contamination and degradation of surface waters in dairying catchments. To investigate the transport and transformations of nitrogen (N) originating from urine, fresh dairy cow urine was collected, amended with the conservative tracer chloride (Cl) and applied onto a loamy sand topsoil, underlain by gritty coarse sands and pumice fragments in the lower part of the vadose zone. The fluxes of the different N components and the conservative tracer leaching from the urine application were measured at five different depths in the vadose zone using three Automated Equilibrium Tension Lysimeters (AETLs) at each depth (max. 5.1 m). The uppermost part of the saturated zone was also monitored for the leached N and Cl fractions from the urine application. Textural changes and hydrophobicity in the vadose zone materials resulted in heterogeneous flow patterns and a high variability in the N and Cl masses captured. All three forms of potentially leachable N from the urine – organic-N (org-N), ammonium-N (NH4-N) and nitrate-N – were measured at the bottom of the root zone at 0.4 m depth. At the 1.0 m depth, effectively all of the captured N was in the mobile nitrate-N form. In the lower part of the vadose zone at 4.2 m, 33% of the applied urine-N was recovered as nitrate-N. This fraction was not significantly different from the corresponding fraction measured at the bottom of the root zone, indicating that no substantial assimilation of the nitrate-N being leached from the root zone was occurring in this vadose zone