Intrinsic and extrinsic controls on the geomorphic condition of upland swamps in Eastern NSW

Fryirs, Kirstie; Cowley, Kirsten L.; Hose, Grant C.

doi:10.1016/j.catena.2015.09.002

Cited by 24 publications

(10 citation statements)

References 59 publications

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“…Typically, the organic soil or peat is 40-60 cm thick, underlain by unconsolidated alluvial sand and sandy silt with organic-rich thin bands. The geomorphology of the Newnes swamps is consistent with the intact swamp classification as reported by Fryirs et al (2016), and with moisture and organic matter content as reported in Blue Mountain swamps by Cowley et al (2016). The lithology indicates that the sediment transport is alluvial; however, it is limited and occurring over relatively short distances (length of the swamp).…”

Section: Swamp Stratigraphy Geomorphology and Groundwater Conditionsupporting

confidence: 83%

“…The significance of groundwater in maintaining the swamp ecosystem function has been discussed in the literature (Chang et al, 2009;Kaller et al, 2015). In Australia, swamp studies have evaluated geomorphology (Fryirs et al, 2016;Cowley et al, 2016), management (Kohlhagen et al, 2013), the relationship between vegetation and groundwater (Hose et al, 2014), processes that result in denudation and sedimentation in the headwaters of the swamps (Prosser et al, 1994), natural and anthropogenic vegetation change in swamps (Bickford and Gell, 2005) and the impact of mining subsidence (CoA, 2014b). However, there is limited literature on the importance of groundwater storage, flow and which water source contributes to maintaining moisture in swamp systems.…”

Section: Introductionmentioning

confidence: 99%

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Application of the pore water stable isotope method and hydrogeological approaches to characterise a wetland system

David

Timms

Hughes

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. Three naturally intact wetland systems (swamps) were characterised based on sediment cores, analysis of surface water, swamp groundwater, regional groundwater and pore water stable isotopes. These swamps are classified as temperate highland peat swamps on sandstone (THPSS) and in Australia they are listed as threatened endangered ecological communities under state and federal legislation. This study applies the stable isotope direct vapour equilibration method in a wetland, aiming at quantification of the contributions of evaporation, rainfall and groundwater to swamp water balance. This technique potentially enables understanding of the depth of evaporative losses and the relative importance of groundwater flow within the swamp environment without the need for intrusive piezometer installation at multiple locations and depths. Additional advantages of the stable isotope direct vapour equilibration technique include detailed spatial and vertical depth profiles of δ18O and δ2H, with good accuracy comparable to other physical and chemical extraction methods. Depletion of δ18O and δ2H in pore water with increasing depth (to around 40–60 cm depth) was observed in two swamps but remained uniform with depth in the third swamp. Within the upper surficial zone, the measurements respond to seasonal trends and are subject to evaporation in the capillary zone. Below this depth the pore water δ18O and δ2H signature approaches that of regional groundwater, indicating lateral groundwater contribution. Significant differences were found in stable pore water isotope samples collected after the dry weather period compared to wet periods where recharge of depleted rainfall (with low δ18O and δ2H values) was apparent. The organic-rich soil in the upper 40 to 60 cm retains significant saturation following precipitation events and maintains moisture necessary for ecosystem functioning. An important finding for wetland and ecosystem response to changing swamp groundwater conditions (and potential ground movement) is that basal sands are observed to underlay these swamps, allowing relatively rapid drainage at the base of the swamp and lateral groundwater contribution. Based on the novel stable isotope direct vapour equilibration analysis of swamp sediment, our study identified the following important processes: rapid infiltration of rainfall to the water table with longer retention of moisture in the upper 40–60 cm and lateral groundwater flow contribution at the base. This study also found that evaporation estimated using the stable isotope direct vapour equilibration method is more realistic compared to reference evapotranspiration (ET). Importantly, if swamp discharge data were available in combination with pore water isotope profiles, an appropriate transpiration rate could be determined for these swamps. Based on the results, the groundwater contribution to the swamp is a significant and perhaps dominant component of the water balance. Our methods could complement other monitoring studies and numerical water balance models to improve prediction of the hydrological response of the swamp to changes in water conditions due to natural or anthropogenic influences.

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Section: Swamp Stratigraphy Geomorphology and Groundwater Conditionsupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Application of the pore water stable isotope method and hydrogeological approaches to characterise a wetland system

David

Timms

Hughes

et al. 2018

Hydrol. Earth Syst. Sci.

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“…Swamps located within the developed areas of the Blue Mountains approximately 100 km west of Sydney NSW, have been particularly degraded due to urbanisation. Factors associated with urbanisation, such as increased impervious area in the catchment and construction of stormwater drains and bores, have altered surface water chemistry [11], water table depths, caused erosion and channelisation, and altered the sediment profiles of the swamps in the Blue Mountains [12].…”

Section: Introductionmentioning

confidence: 99%

“…Restoration efforts have attempted to re-establish the hydrological processes within swamps by stopping or reversing erosion or buffering flashy stormwater flows [13, 14]. While restoration of swamp hydrology and sedimentary structure is critical to restoring ecological functions [12, 13, 15], other symptoms of urbanisation, such as altered water chemistry, must also be addressed. High concentrations of nutrients [16] are a common side effect of urbanisation in surface waters.…”

Section: Introductionmentioning

confidence: 99%

The impact of urbanisation on community structure, gene abundance and transcription rates of microbes in upland swamps of Eastern Australia

et al. 2019

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The Temperate Highland Peat Swamps on Sandstone of the Sydney Basin occur in the headwaters of Sydney’s drinking water catchments and are listed as endangered ecosystems, yet they have suffered habitat losses and degradation due to human impacts such as urbanisation. Despite ongoing efforts to restore and better protect upland swamps, they remain poorly understood, potentially hindering the effectiveness of management efforts. Essential to overall ecosystem function and the provision of services for human and environmental benefit are the microbial component of wetland ecosystems. In the case of these swamps, the microbes, have not yet been studied. Here, we investigated differences in the microbial community of upland swamps in urbanised catchments compared to swamps from natural catchments in the Blue Mountains. A total of twelve swamps were sampled, six from within urbanised catchments and six with intact vegetation catchments, to compare sediment conditions and microbial community and genes expression and abundances. Catchment impervious area and number of stormwater drains entering a swamp, indicators for urbanisation, positively correlated with the pH and ammonium concentration of swamp sediment. Community analysis of the 16S rRNA gene (T-RFLP, qPCR) revealed the elevated pH of urbanised swamps coincided with changes to the abundance of bacteria and archaea. Furthermore, RT-qPCR revealed genes involved in carbon cycling ( mcrA & pmoA ) were more likely to be found in urbanised swamps. Taken together, our results indicate that urbanisation of the Blue Mountains is impacting the environmental services provided by the microbial community of upland swamps in the Sydney Basin.

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“…THPSS and peatland systems globally are under considerable stress from anthropogenic activities operating at different spatial scales [18][19][20]. Degradation from swamp drainage, channelization and peat extraction is well documented [3,[21][22][23][24]. However, impacts from indirect, catchment-scale activities such as underground (longwall) mining and groundwater extraction have not been widely studied [25].…”

Section: Introductionmentioning

confidence: 99%

Water Sources of Upland Swamps in Eastern Australia: Implications for System Integrity with Aquifer Interference and a Changing Climate

Cowley

Fryirs

Chisari

et al. 2019

Water

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Temperate Highland Peat Swamps on Sandstone (THPSS) in Eastern Australia are Groundwater Dependent Terrestrial Ecosystems that occur in the headwaters of streams on low relief plateaus. Like upland swamps and peatlands globally, they provide base flow to downstream catchments. However, these swamps are subject to aquifer interference from mining and groundwater extraction and are threatened by urbanization and climate change. We collected winter and summer water samples from swamps in two highland regions of Eastern Australia. Water from the swamps was analyzed for hydrogen (δ2H) and oxygen (δ18O) isotopes and compared with rainwater, surface water and groundwater samples from the surrounding bedrock aquifers to identify likely swamp water sources. Radon (222Rn) was used as an environmental tracer to determine whether the swamps were predominantly groundwater or rainwater fed. Four out of five swamps sampled in the Blue Mountains had greater than 30% of water derived from the surrounding bedrock aquifer, whereas swamps in the Southern Highlands received less than 15% of water from the surrounding aquifer. The water sources for swamps in both regions are controlled by catchment morphology, e.g., valley shape. Understanding water sources of these systems is critical for the determination of likely impacts on THPSS from aquifer interference activities and a changing climate.

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Intrinsic and extrinsic controls on the geomorphic condition of upland swamps in Eastern NSW

Cited by 24 publications

References 59 publications

Application of the pore water stable isotope method and hydrogeological approaches to characterise a wetland system

Application of the pore water stable isotope method and hydrogeological approaches to characterise a wetland system

The impact of urbanisation on community structure, gene abundance and transcription rates of microbes in upland swamps of Eastern Australia

Water Sources of Upland Swamps in Eastern Australia: Implications for System Integrity with Aquifer Interference and a Changing Climate

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