Hydrology and ecohydrology of Australian semi‐arid wetlands

Lamontagne, Sébastien; Herczeg, Andrew L.

doi:10.1002/hyp.7462

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…The resulting time series of SW extent served as the dependent variable for each SW category and was modeled as a function of all driver variables, using a dynamic multivariate regression framework. In order to analyze the role of local climate conditions in SW dynamics, we used spatially explicit daily time series of P, ET, and SM as additional driver variables (hereafter referred to as local climate drivers) besides river flow, which are all known to influence the magnitude and duration of floods [S anchez-Carrillo et al, 2004;Lamontagne and Herczeg, 2009]. The selection criteria for the corresponding data sets were that they had to be spatially explicit and cover the entire analysis period.…”

Section: Driver Variables and Data Preparationmentioning

confidence: 99%

Modeling multidecadal surface water inundation dynamics and key drivers on large river basin scale using multiple time series of Earth‐observation and river flow data

Heimhuber

Tulbure

Broich

2017

Water Resources Research

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Periodically inundated floodplain areas are hot spots of biodiversity and provide a broad range of ecosystem services but have suffered alarming declines in recent history. Despite their importance, their long‐term surface water (SW) dynamics and hydroclimatic drivers remain poorly quantified on continental scales. In this study, we used a 26 year time series of Landsat‐derived SW maps in combination with river flow data from 68 gauges and spatial time series of rainfall, evapotranspiration and soil moisture to statistically model SW dynamics as a function of key drivers across Australia's Murray‐Darling Basin (∼1 million km2). We fitted generalized additive models for 18,521 individual modeling units made up of 10 × 10 km grid cells, each split into floodplain, floodplain‐lake, and nonfloodplain area. Average goodness of fit of models was high across floodplains and floodplain‐lakes (r2 > 0.65), which were primarily driven by river flow, and was lower for nonfloodplain areas (r2 > 0.24), which were primarily driven by rainfall. Local climate conditions were more relevant for SW dynamics in the northern compared to the southern basin and had the highest influence in the least regulated and most extended floodplains. We further applied the models of two contrasting floodplain areas to predict SW extents of cloud‐affected time steps in the Landsat series during the large 2010 floods with high validated accuracy (r2 > 0.97). Our framework is applicable to other complex river basins across the world and enables a more detailed quantification of large floods and drivers of SW dynamics compared to existing methods.

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Section: Driver Variables and Data Preparationmentioning

confidence: 99%

Modeling multidecadal surface water inundation dynamics and key drivers on large river basin scale using multiple time series of Earth‐observation and river flow data

Heimhuber

Tulbure

Broich

2017

Water Resources Research

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“…Our results indicate that for a diverse and abundant zooplankton community typical of freshwater wetlands to be reinstated, salinities would need to be lowered to and maintained below 2500 mg L )1 . However, the prospects for rehabilitation of impacted freshwater wetlands will be limited unless the underlying causes for secondary salinisation are addressed (Lamontagne & Herczeg, 2009).…”

Section: Discussionmentioning

confidence: 99%

Resting egg banks can facilitate recovery of zooplankton communities after extended exposure to saline conditions

2012

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Summary 1. Salinisation has had a major effect on the diversity of biota associated with freshwater wetlands. However, there is no information available about whether elements of the biotic communities would be able to recover if the concentration of salts within secondarily salinised wetlands was lowered to levels more typical of freshwater wetlands. 2. We tested the hypothesis that dormant eggs of zooplankton are able to persist in wetlands with elevated salinities for extended periods of time by using zooplankton communities that had developed in mesocosms exposed to either salt concentrations of 13 500 mg L−1 or freshwater (<300 mg L−1) for a period of 22 months. We measured the response of the zooplankton community as concentration was reduced along a gradient of decreasing salinity from 13 500 mg L−1 to freshwater. 3. In the freshwater mesocosms, the zooplankton community was abundant and taxon rich. In comparison at the start of the experiment in the high salinity mesocosms, the zooplankton community had low abundances and very few taxa. Numbers remained low in these mesocosms until salinity was reduced to <2500 mg L−1. Below this, there was a rapid increase in the abundance, and richness of zooplankton and communities became similar to the communities in the freshwater mesocosms. 4. These results indicate that dormant eggs of zooplankton are able to persist in wetlands exposed to high salinity levels for up to 22 months and provide a means for zooplankton communities to rapidly respond once a wetland returns to freshwater. 5. It is likely that if the underlying causes of secondary salinisation in wetlands are addressed, it will be possible to undertake restoration activities that allow the rapid return of some components of their biotic communities.

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“…Increased soil moisture (SM) prior to flooding usually leads to reduced transmission losses and thus to a larger flood extent and longer flood duration for a given flow level compared to dry antecedent conditions of the floodplain (Overton, 2005). Additionally, evapotranspiration (ET) is a major component of the water balance of surface water bodies especially in semi-arid regions such as the MDB (Lamontagne and Herczeg, 2009;Sánchez-Carrillo et al, 2004). Besides river flow as the key driver for floodplain inundation, five of the studies that developed EO-based inundation models accounted for P and four of them also for ET during or before flooding, whereas only one study accounted for the antecedent SM condition of the floodplain (Table 1).…”

Section: Introductionmentioning

confidence: 99%

Modeling 25 years of spatio-temporal surface water and inundation dynamics on large river basin scale using time series of Earth observation data

Heimhuber

Tulbure

Broich

2016

Hydrol. Earth Syst. Sci.

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Abstract. The usage of time series of Earth observation (EO) data for analyzing and modeling surface water extent (SWE) dynamics across broad geographic regions provides important information for sustainable management and restoration of terrestrial surface water resources, which suffered alarming declines and deterioration globally. The main objective of this research was to model SWE dynamics from a unique, statistically validated Landsat-based time series continuously through cycles of flooding and drying across a large and heterogeneous river basin, the Murray-Darling Basin (MDB) in Australia. We used dynamic linear regression to model remotely sensed SWE as a function of river flow and spatially explicit time series of soil moisture (SM), evapotranspiration (ET), and rainfall (P ). To enable a consistent modeling approach across space, we modeled SWE dynamics separately for hydrologically distinct floodplain, floodplain-lake, and non-floodplain areas within ecohydrological zones and 10 km × 10 km grid cells. We applied this spatial modeling framework to three sub-regions of the MDB, for which we quantified independently validated lag times between river gauges and each individual grid cell and identified the local combinations of variables that drive SWE dynamics. Based on these automatically quantified flow lag times and variable combinations, SWE dynamics on 233 (64 %) out of 363 floodplain grid cells were modeled with a coefficient of determination (r 2 ) greater than 0.6. The contribution of P , ET, and SM to the predictive performance of models differed among the three sub-regions, with the highest contributions in the least regulated and most arid sub-region. The spatial modeling framework presented here is suitable for modeling SWE dynamics on finer spatial entities compared to most existing studies and applicable to other large and heterogeneous river basins across the world.

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Hydrology and ecohydrology of Australian semi‐arid wetlands

Cited by 6 publications

References 11 publications

Modeling multidecadal surface water inundation dynamics and key drivers on large river basin scale using multiple time series of Earth‐observation and river flow data

Modeling multidecadal surface water inundation dynamics and key drivers on large river basin scale using multiple time series of Earth‐observation and river flow data

Resting egg banks can facilitate recovery of zooplankton communities after extended exposure to saline conditions

Modeling 25 years of spatio-temporal surface water and inundation dynamics on large river basin scale using time series of Earth observation data

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