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NZ River Maps: An interactive tool for mapping predicted freshwater variables across New Zealand

Authors:
Douglas James Booker at National Institute of Water and Atmospheric Research
Douglas James Booker
Amy Whitehead at Manaaki Whenua - Landcare Research
Amy Whitehead
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Abstract

NIWA has calculated estimates of environmental conditions across the entire New Zealand river network, including hydrology, ecology and water quality metrics. This interactive webtool allows you to map and interrogate these estimates. In addition, you can intersect the NIWA estimates with publicly-available council planning layers and view a simplified representation of the river network.
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NZRiverMa
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Content uploaded by Amy Whitehead
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All content in this area was uploaded by Amy Whitehead on May 27, 2018
Content may be subject to copyright.
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... River sediment load and flow data were extracted from the New Zealand River Maps database (Booker and Whitehead, 2017) (NZ River Maps © 2016 NIWA, Version 1.0.0 1 ). On the east coast, there are three major rivers that could deliver terrigenous sediment to the Kaikōura canyon: the Hurunui, Waiau and Conway rivers. ...
... This high sediment load is a function of the higher rainfall intensity and steeper land slopes on the west coast of South Island (Adams, 1980;Hicks et al., 2011;Jiao et al., 2017). Consequently, because the west coast river catchments are very much smaller and have higher mean annual flows than those on the east coast with more flood events per year (Booker and Whitehead, 2017) the water discharged from the west coast rivers is likely to have higher energy, potentially pushing the sediment load farther from shore where it can be intercepted by the longshore drift system and transported into the Hokitika Canyon. ...
... Comparison data for the west coast and east coast South Island rivers, extracted from the New Zealand River Maps database(Booker and Whitehead, 2017).Rivers listed in order from north to south (see text on mixing models for explanation of Prior). *Combined Mikonui, Waitaha, Wanganui and Whataroa rivers (see text for explanation). ...
Novel Application of a Compound-Specific Stable Isotope (CSSI) Tracking Technique Demonstrates Connectivity Between Terrestrial and Deep-Sea Ecosystems via Submarine Canyons
Article
Full-text available
  • Jul 2020
Studies have shown the importance of submarine canyons as conduits of land-derived organic carbon beyond the coastal shelf into the deep-sea where a single obvious river source can be identified. When there is more than one river source, identifying which rivers contribute to canyon sediment organic matter is technically challenging. Here, we compare two contrasting submarine canyons: the Hokitika Canyon, a long, narrow, and gently sloping canyon on the west coast of New Zealand; and the Kaikōura Canyon, a high productivity, short, steep canyon close to shore on the east coast of New Zealand. Both canyons have multiple potential river sources, so we applied a compound specific stable isotope (CSSI) tracking technique to identify and apportion the contribution from each river at locations along the length of each canyon axis. We found that land-derived organic matter contributed between 74 and 100% of the total organic matter in the sediment of the Hokitika Canyon as far as 200 km from shore and to depths of 2000 m. However, less than 50% of the land-derived organic carbon came from the largest river closest to the canyon head. We hypothesize that longshore drift transported much of the sediment from that river past the Hokitika Canyon, while river inflows farther up-current supplied the bulk of the land-derived organic carbon. In contrast, land-derived organic matter contributed less than 50% of the total organic matter in Kaikōura Canyon sediments with land-derived organic sediment contribution decreasing steeply to less than 15% at about 24 km from shore in 1500 m water depth. Most of the land-derived organic matter (ca. 80%) came from the river with the largest suspended sediment yield, despite another (smaller) river discharging closer to the canyon head. We hypothesize that this difference in carbon source is partly due to the comparatively short and steep, and therefore dynamic, nature of Kaikōura Canyon resulting in efficient sediment through-put. The efficiency with which organic matter is captured and transferred to the deep-sea by canyons demonstrates the potential for such systems to act as natural carbon sinks driven by both geologically episodic and more regular oceanographic processes.
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... Esta herramienta basada en el web fue desarrollada por el Dr. Doug Brooker y la Dra. Amy Whitehead, con financiamiento del Programa de Asignación Sostenible del Agua (Sustainable Water Allocation Programme, SWAP por sus siglas en en el idioma inglés), del Instituto Nacional de Investigación del Agua y la Atmósfera (National Institute of Water and Atmospheric Research, NIWA por sus siglas en inglés), de Nueva Zelanda [10]. ...
... La investigación sobre los índices hidrológicos, el ancho del lecho, la cobertura de sedimentos del lecho, el hábitat de los peces y los índices de invertebrados también fue financiado por SWAP. Las estimaciones de la presencia/ausencia de peces y la idoneidad del hábitat, fueron financiadas por el Departamento de Conservación y la Universidad de Canterbury, respectivamente, mientras que la investigación sobre el estado de la calidad del agua y el uso consentido del agua, fue financiada por el Ministerio del Medio Ambiente de Nueva Zelanda [10]. La herramienta permite a los usuarios visualizar cómo se distribuyen espacialmente los afluentes, polígonos de la cuenca y generar gráficos. ...
... Visualización de afluentes y polígonos de cuencas zona Canterbury, NZ[10]. ...
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... The system needs a permanent flow to maintain operation, so we assume the system is sized to treat 75% of the mean annual low flow (MALF) of the stream being treated. Flow data are sourced from NZ River Maps [47]. During seasonal low flow periods, particularly in drought periods, this may not be a realistic quantity to extract, even temporarily. ...
Evaluating the Cost-Effectiveness of Green Infrastructure for Mitigating Diffuse Agricultural Contaminant Losses
Article
Full-text available
  • May 2024
New Zealand’s agricultural sector faces the challenge of maintaining productivity while minimizing impacts on freshwaters. This study evaluates the cost-effectiveness of various green infrastructure systems designed to reduce diffuse agricultural sediment and nutrient loads. Utilizing a quantitative economic and contaminant reduction modeling approach, we analyze the impacts of five interceptive mitigation systems: riparian grass filter strips, constructed wetlands, woodchip bioreactors, filamentous algal nutrient scrubbers, and detainment bunds. Our approach incorporates Monte Carlo simulations to address uncertainties in costs and performance, integrating hydrological flow paths and contaminant transport dynamics. Mitigation systems are assessed individually and in combination, using a greedy cyclical coordinate descent algorithm to find the optimal combination and scale of a system for a particular landscape. Applying the model to a typical flat pastoral dairy farming landscape, no single system can effectively address all contaminants. However, strategic combinations can align with specific freshwater management goals. In our illustrative catchment, the mean cost to remove the full anthropogenic load is NZD 1195/ha for total nitrogen, NZD 168 for total phosphorus, and NZD 134 for suspended solids, but results will vary considerably for other landscapes. This study underscores the importance of tailored deployment of green infrastructure to enhance water quality and support sustainable agricultural practices.
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... The volumes of freshwater discharges to the Inlet from streams and rivers are low compared to the volumes of water exchanged by the tides. The main freshwater discharge to the Inlet is from the Waimea River and its tributaries (mean annual flow is 27.5 m 3 /s) [27]. ...
Monitoring Intertidal Habitats for Effects from Biosolids Applications onto an Adjacent Forestry Plantation
Article
Full-text available
  • Aug 2023
Stabilised organic solids derived from sewage sludge (“biosolids”) are applied to land as an alternative to disposal as landfill. This study evaluated the long-term effects of biosolids applied to forestry plantations on the adjacent intertidal habitats of Rabbit Island (New Zealand). On this island, biosolids are applied to enhance the growth of trees (Pinus radiata). Shoreline topography, macroalgal cover, sediment grain size, the concentrations of nutrients, trace metals, and faecal indicator bacteria, and benthic infaunal communities were studied in 2008, 2014, and 2019 at twelve intertidal transect sites (four “reference” and eight “application”) adjacent to forestry blocks where biosolids have been applied over a period of 24 years. The sediment composition did not differ significantly between the survey years or between the reference and application sites. Total nitrogen concentrations in the sediments increased over time at some transects, but such increases were not consistent among the application transects. No symptoms of excessive algal growth, sediment anoxia, and hydrogen sulphide odours were observed at most sites. Key infaunal taxa were similar between the reference and application transects. Overall, no long-term adverse changes to intertidal habitats attributed to biosolids application were detected between the reference and application sites. This study shows that biosolids application can co-occur without detectable adverse effects on nearby intertidal environments. In a global context of rising concern over climate change, environmental pollution, and resource scarcity, forest fertilisation with biosolids can facilitate biomass production and soil development while protecting valued coastal ecosystems.
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... Although there are several interactive web applications developed by various organisations around the world to monitor and introduce the hydrological properties of basins, watersheds, and streams (USGS, 2007;Harvard University, 2008;Conservation Biology Institute, 2010;Environment Canada, 2012;UN, 2016;WWF, 2016;Booker and Whitehead, 2017;The Rivers Trust, 2020;CANHN, 2021;EPA, 2021;Trust, 2021;US EPA, 2021;USGS, 2021;Environment Agency, 2022;NCDEQ, 2022), when viewed on a global scale, it is clear that these applications are insufficient, particularly in terms of morphometric characteristics, because they only cover the borders of that country or state, use limited data, and none exist for obtaining watershed morphometric characteristics. ...
Morphometric analysis in Google Earth Engine: An online interactive web-based application for global-scale analysis
Article
  • Feb 2023
  • ENVIRON MODELL SOFTW
Abstract Morphometric analysis of a basin or watershed describes the physical characteristics of the basin that are useful for environmental studies. Watershed morphometric characteristics are based on the terrain processing that must be done for each different watershed. There is no application that provides basin morphometric characteristics, basin borders, and streams in the basin on a global scale, so the development of a new application has become a necessity. In this research, an online Google Earth Engine (GEE) application has been developed that determines the morphometric characteristics of any watershed on a global scale using digital elevation models, basin boundaries, and river stream data. The Meriç basin was selected for testing the application. The results of the application were validated by comparing them to ArcGIS. The findings demonstrate that, in the absence of GIS software or data, GEE may be used to determine basin morphometric characteristics on a worldwide scale. The GEE application is now available online. In addition, application codes and user guide were also shared on github. In particular, it may be useful for GEE developers working on basin morphology. There are links: https://authors.elsevier.com/sd/article/S1364-8152(23)00026-9 https://mynet34.users.earthengine.app/view/nku-man https://github.com/mcarslanoglu/nkuman
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... Indeed, whio populations are already benefiting from an expansion of predator control networks by both government agencies and local community groups [30,32,59]. To help facilitate prioritisation of future conservation efforts for whio, we have made the predictions of mean RLO for whio under contemporary habitat conditions available via the NZ River Maps webtool (https:// shiny.niwa.co.nz/nzrivermaps), an online platform for visualising environmental data on the New Zealand digital river network [60,61]. Feb & segFlowStability 30.6 ± 9.6 a) Mean (± sd) relative contribution of the predictors. ...
Quantifying the relative contributions of habitat modification and mammalian predators on landscape-scale declines of a threatened river specialist duck
Article
Full-text available
Habitat modification and introduced mammalian predators are linked to global species extinctions and declines, but their relative influences can be uncertain, often making conservation management difficult. Using landscape-scale models, we quantified the relative impacts of habitat modification and mammalian predation on the range contraction of a threatened New Zealand riverine duck. We combined 38 years of whio ( Hymenolaimus malacorhynchos ) observations with national-scale environmental data to predict relative likelihood of occurrence (RLO) under two scenarios using bootstrapped boosted regression trees (BRT). Our models used training data from contemporary environments to predict the potential contemporary whio distribution across New Zealand riverscapes in the absence of introduced mammalian predators. Then, using estimates of environments prior to human arrival, we used the same models to hindcast potential pre-human whio distribution prior to widespread land clearance. Comparing RLO differences between potential pre-human, potential contemporary and observed contemporary distributions allowed us to assess the relative impacts of the two main drivers of decline; habitat modification and mammalian predation. Whio have undergone widespread catastrophic declines most likely linked to mammalian predation, with smaller declines due to habitat modification (range contractions of 95% and 37%, respectively). We also identified areas of potential contemporary habitat outside their current range that would be suitable for whio conservation if mammalian predator control could be implemented. Our approach presents a practical technique for estimating the relative importance of global change drivers in species declines and extinctions, as well as providing valuable information to improve conservation planning.
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... These parameters included well depth, spot measurements of water temperature, conductivity and pH, and nutrient concentrations (DRP, TDN, TDP, nitrate-N, nitrite-N, ammoniacal-N). For each assigned aquifer, the diversity of amphipods per 1000 km 2 of surface catchment area (from Booker & Whitehead, 2017) and aquifer area (from Ministry for the Environment, 2015) was calculated. ...
High diversity and local endemism in Aotearoa New Zealand's groundwater crustacean fauna
Article
Full-text available
  • Oct 2021
We used DNA barcoding to assess the diversity and distribution of New Zealand's groundwater amphipods and isopods (Crustacea) and to determine whether biodiversity and endemism within tectonically active New Zealand are similar to those of more tectonically stable continents. Sixty-five wells were sampled in seven aquifers across four regions within the North and South islands of New Zealand, and resident invertebrates were morphologically identified and then assessed using sequencing of the mitochondrial DNA cytochrome c oxidase subunit one (COI) gene. Invertebrates were found in 54 wells. Of the 228 individual amphipods and isopods found in 36 of the wells, 154 individuals were successfully sequenced for COI (68% success rate) from 25 wells, with at least one well in each aquifer containing sequenced individuals. Of the 45 putative species identified using Barcode Index Numbers (BINs), 30 BINs (78% of all taxa and 83% of amphipods) were previously unrecorded. Substantial morphologically cryptic, species-level diversity was revealed, particularly within the amphipod Family Paraleptamphopidae. Similarly, one isopod taxon morphologically identified as Cruregens fontanus was assigned to five well-separated BINs based on COI sequences. Endemism appeared high, with all taxa regionally endemic; 87% of species were restricted to one aquifer and more than 50% restricted to one well. Non-saturated species accumulation curves indicated that, while additional sampling may increase the range of some currently identified taxa, additional range-restricted taxa are also likely to be discovered. Patterns of diversity and short-range endemism were similar to those found elsewhere, including locations which are more tectonically stable. The predominance of local endemism within New Zealand's groundwater fauna suggests that land-use activities and groundwater extraction require careful evaluation to minimize threats to groundwater biodiversity.
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... ORC (2019) monitor the flow of the Matukituki at West Wānaka, where the median flow is approximately 45 m 3 /s, with flood flows sometimes exceeding 1,500 m 3 /s. There is no flow monitoring station on the Makarora, but a rain gauge maintained by ORC records a mean annual rainfall of 2,396 mm, and NIWA's Rivermaps model predicts a median flow of 97 m 3 /s (Booker and Whitehead, 2017). ...
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A method for predicting hydrogen and oxygen isotope distributions across a region's river network using reach-scale environmental attributes
Article
Full-text available
  • Oct 2022
  • HESS
Stable isotope ratios (isotope values) of surface water reflect hydrological pathways, mixing processes, and atmospheric exchange within catchments. Development of maps of surface water isotope values (isoscapes) is limited by methods to interpolate point measures across river networks. Catchment attributes that alter surface water isotope values affect downstream river reaches via flow, but some attributes such as artificial dams are no more likely to affect nearby unconnected catchments than distant ones. Hence, simple distance-based geospatial and statistical interpolation methods used to develop isoscapes for precipitation and terrestrial systems are less appropriate for river networks. We used a water-balance-based method to map long-term average δ2H and δ18O for New Zealand rivers, incorporating corrections using catchment environmental predictors. Inputs to the model are national rainfall precipitation isoscapes, a digital elevation layer, a national river water isotope monitoring dataset (3 years of monthly sampling at 58 sites), and river environmental databases covering around 600 000 reaches and over 400 000 km of rivers. Much of the spatial variability in δ2H and δ18O of New Zealand river water was explained using the initial combination of precipitation isoscapes and a simple water balance model. δ2H and δ18O isoscapes produced by subsequently applying residuals from the water balance model as a correction factor across the river network using regression kriging showed improved fits to the validation data compared to the correction using ordinary kriging. Predictors of high importance in the regression included upstream lake and wetland area, which was not strongly spatially autocorrelated nationally. Hence, additional hydrological process information such as evaporation effects can be incorporated into river isoscapes using regression kriging of residuals. The resulting isoscapes have potential applications in ecological, hydrological, and provenance studies that consider differences between surface water isotope values and those of other components of the hydrological cycle (e.g. subsurface runoff or local precipitation).
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Long-term monitoring indicates no adverse effects to intertidal habitats from biosolids applications onto an adjacent coastal forestry plantation
Preprint
Full-text available
  • Jul 2022
Stabilised organic solids derived from sewage sludge ('biosolids') are applied to land in many countries as an alternative to disposal as land ll. This study evaluates the long-term effects of biosolids applied to forestry plantations on the adjacent intertidal habitats of Moturoa / Rabbit Island (Aotearoa New Zealand). On this island, biosolids are applied to enhance soil fertility and growth of trees (Pinus radiata). However, applications may affect the quality of groundwater and surface water (e.g., increasing concentrations of nutrients and trace metals) and, via seepage into adjacent coastal areas, potentially adversely affect intertidal habitats and biota. Shoreline topography, macroalgal cover, sediment grain size, concentrations of nutrients, trace metals and faecal indicator bacteria, and benthic infaunal community characteristics were studied on three occasions (2008, 2014 and 2019) at twelve intertidal transect sites (four 'reference' and eight 'application') adjacent to forestry blocks where biosolids have been applied intermittently over a period of 24 years. No long-term adverse changes to the environment and community characteristics attributed to biosolids application were detected between reference and application sites. The study provides evidence that biosolids application can co-occur without detectable adverse effects on the nearby intertidal environment.
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