Dissertations / Theses on the topic 'Forested catchment'
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1
Osaka, Ken'ichi. "Hydro-biogeochemical study on denitrification in a temperate forested catchment." Kyoto University, 2007. http://hdl.handle.net/2433/136560.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第13306号
農博第1648号
新制||農||946(附属図書館)
学位論文||H19||N4285(農学部図書室)
UT51-2007-H671
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 谷 誠, 教授 武田 博清, 教授 小﨑 隆
学位規則第4条第1項該当
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James, April Lynda. "Investigating small multiple catchment runoff generation in a forested temperate watershed." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100630.
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Runoff generation refers to the physical processes by which water travels through the landscape, moving through the subsurface or over the ground surface, ultimately arriving at the stream channel. These physical processes vary in both space and time leading to difficulties in mechanistic modelling of storm response, contaminant transport and nutrient fluxes. Runoff generation has been extensively studied at the hillslope scale and in headwater catchments. However, only recently have empirical studies begun to collect similarly detailed datasets across multiple catchments with which to examine how these processes change with scale. This study examines runoff generation from a series of eight small nested forest catchments and focuses specifically on the controlling influences of antecedent moisture conditions and catchment topography.End-member-mixing-analysis using stream water hydrochemistry from the eight catchments shows changing seasonal and storm-based source water contributions to the stream channel. Analysis identifies hydrochemical solutes with behaviour consistent with the assumptions of the mixing-model approach for all eight catchments. Results indicate that testing of solute selection is critical in the application of this method to multiple catchments.
Runoff generation observed for five storm events shows a strong nonlinear relationship between runoff and antecedent moisture conditions, supporting the hypothesis of varying 'states of wetness'. Detailed hillslope-scale investigation during the different 'states of wetness' indicates that while groundwater and soil moisture profiles show changing active-flow connectivity on a seasonal and storm-base dtime scale, there no significant change in spatial patterns of shallow soil moisture. These results suggest that a priori spatial patterns in shallow soil moisture in forested terrains may not be a good predictor of critical hydrologic connectivity that leads to the threshold change in runoff generation, as has been found in rangeland catchments.
Differences in storm response from the eight catchments are in part attributable to variation in topography and landscape organization. The multiple catchments have similar distributions of topographic index and yet differences in mean values of topographic index lead to significantly different estimates of mean residence time. Scaling of storm response is dominated by the behaviour of the three largest catchments. These three catchments distinguish themselves with larger MRT and larger valley bottom areas. It is these three catchments that, under dry antecedent moisture conditions, show significantly larger amounts of new water delivery to the stream channel, suggesting a significant change in dominant runoff mechanisms related to topography and landscape organization.
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Dalva, Moshe. "Pathways, patterns and dynamics of dissolved organic carbon in a temperate forested swamp catchment." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59625.
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Inputs of DOC in precipitation were low and increased with the passage of rainfall through different canopies. Throughfall, stemflow, leachates from A horizons and litterfall were identified as sources of DOC, while B and C horizons in upland areas provide a sink. Throughfall and stemflow displayed high temporal variability in DOC concentrations, while soil leachates and peat waters exhibited strong seasonal patterns. DOC concentrations in throughfall, stemflow and A horizons were highest in the predominantly coniferous site. In the fall, DOC concentrations from A horizons in the deciduous site were significantly higher than those from the coniferous site.Factors influencing DOC in peat waters are: (1) peat thermal regime, (2) water chemistry, and (3) water table position. Large storms ($>$30 mm precipitation) appear to be the primary factor influencing exports of DOC in streamflow, particularly following dry antecedant soil moisture conditions. Slow rates of water movement through compact deep peats ($>$60 cm depth) and adsorption of DOC in B and C horizons of this catchment obstruct exports of DOC, which over the 5.5 month study period, were minimal in comparison to inputs.
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Scaini, Anna. "Velocity and celerity in a forested headwater catchment : a combined experimental and modelling approach." Thesis, Lancaster University, 2017. http://eprints.lancs.ac.uk/89756/.
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One of the most important issues in modern hydrology is to improve our understanding of the release of old water during rainfall events. This thesis approaches the problem of estimating velocities, a measure of water transport, and celerities, a measure of the hydrograph response. We aim at measuring and interpreting estimates of velocity and celerity in a consistent way using in situ data. For this purpose, we performed multi-tracer irrigation experiments at different scales, from soil column to hillslope, to a sub-catchment scale analysis in a forested headwater catchment characterised by fractured bedrock. Our field experiments proved the importance of bedrock cleavage orientation in controlling subsurface flow direction and demonstrated the importance of quantifying the extent of fractures as well as their orientation relative to dominant topographically related flowpaths. An undisturbed soil column experiment was used in a hypothesis-testing framework in combination with a Multiple Interacting Pathways (MIPs) model. The use of a transition probability matrix (TPM) in combination with immobile water and variable field capacity parameters allowed the representation both volume and tracer dynamics. A framework to estimate both velocities and celerities using commonlyavailable hydrometric and tracer data is presented, emphasising the importance of choosing appropriate distance information as it can strongly influence the estimates and thereby the interpretation of controls on catchment function. The analysis of velocities and celerities at different spatial and temporal scales showed that the relationship between velocity and celerity shows a positive relation at the stream outlet. The experimentally-derived velocities and celerities metrics hereby explored have the potential to contribute to the evaluation hypothesis regarding catchment storage and release of water, by providing a direct comparison of what controls the old-water paradox.
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Julich, Stefan, Raphael Benning, Dorit Julich, and Karl-Heinz Feger. "Quantification of Phosphorus Exports from a Small Forested Headwater-Catchment in the Eastern Ore Mountains, Germany." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230637.
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Phosphorus (P) export from forest soils is mainly driven by storm events, which induce rapid flow processes by preferential flow bypassing large parts of the soil matrix. However, little is known about the dynamics, magnitude, and driving processes of P exports into surface waters. In this paper, we present the results of a monitoring study in a small forested catchment (21 ha) situated in the low mountain ranges of Saxony, Germany. During the fixed schedule-sampling (weekly to bi-weekly sampling frequency for a three-year period), a mean total-P concentration of 8 μg·L−1 was measured. However, concentrations increased up to 203 μg·L−1 during individual storm flow events. Based on the analyzed concentrations and continuously measured discharge we calculated mean annual export rates of 19 to 44 g·ha−1·a−1 for the weekly sampling frequency with different load calculation methods. If events are included into the annual load calculation, the mean annual export fluxes can be up to 83 g·ha−1·a−1 based on the different load calculation methods. Predictions of total-P export rates based on a sampling strategy which does not consider short-term changes due to factors such as storms will substantially underestimate P exports.
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Löhr, Stefan Carlos. "Controls on iron in soils and soil waters of a forested, coastal catchment in subtropical Australia." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/47012/1/Stefan_L%C3%B6hr_Thesis.pdf.
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Soluble organic matter derived from exotic Pinus vegetation forms stronger complexes with iron (Fe) than the soluble organic matter derived from most native Australian species. This has lead to concern about the environmental impacts related to the establishment of extensive exotic Pinus plantations in coastal southeast Queensland, Australia. It has been suggested that the Pinus plantations may enhance the solubility of Fe in soils by increasing the amount of organically complexed Fe. While this remains inconclusive, the environmental impacts of an increased flux of dissolved, organically complexed Fe from soils to the fluvial system and then to sensitive coastal ecosystems are potentially damaging. Previous work investigated a small number of samples, was largely laboratory based and had limited application to field conditions. These assessments lacked field-based studies, including the comparison of the soil water chemistry of sites associated with Pinus vegetation and undisturbed native vegetation. In addition, the main controls on the distribution and mobilisation of Fe in soils of this subtropical coastal region have not been determined. This information is required in order to better understand the relative significance of any Pinus enhanced solubility of Fe. The main aim of this thesis is to determine the controls on Fe distribution and mobilisation in soils and soil waters of a representative coastal catchment in southeast Queensland (Poona Creek catchment, Fraser Coast) and to test the effect of Pinus vegetation on the solubility and speciation of Fe. The thesis is structured around three individual papers. The first paper identifies the main processes responsible for the distribution and mobilisation of labile Fe in the study area and takes a catchment scale approach. Physicochemical attributes of 120 soil samples distributed throughout the catchment are analysed, and a new multivariate data analysis approach (Kohonen’s self organising maps) is used to identify the conditions associated with high labile Fe. The second paper establishes whether Fe nodules play a major role as an iron source in the catchment, by determining the genetic mechanism responsible for their formation. The nodules are a major pool of Fe in much of the region and previous studies have implied that they may be involved in redox-controlled mobilisation and redistribution of Fe. This is achieved by combining a detailed study of a ferric soil profile (morphology, mineralogy and micromorphology) with the distribution of Fe nodules on a catchment scale. The third component of the thesis tests whether the concentration and speciation of Fe in soil solutions from Pinus plantations differs significantly from native vegetation soil solutions. Microlysimeters are employed to collect unaltered, in situ soil water samples. The redox speciation of Fe is determined spectrophotometrically and the interaction between Fe and dissolved organic matter (DOM) is modelled with the Stockholm Humic Model. The thesis provides a better understanding of the controls on the distribution, concentration and speciation of Fe in the soils and soil waters of southeast Queensland. Reductive dissolution is the main mechanism by which mobilisation of Fe occurs in the study area. Labile Fe concentrations are low overall, particularly in the sandy soils of the coastal plain. However, high labile Fe is common in seasonally waterlogged and clay-rich soils which are exposed to fluctuating redox conditions and in organic-rich soils adjacent to streams. Clay-rich soils are most common in the upper parts of the catchment. Fe nodules were shown to have a negligible role in the redistribution of dissolved iron in the catchment. They are formed by the erosion, colluvial transport and chemical weathering of iron-rich sandstones. The ferric horizons, in which nodules are commonly concentrated, subsequently form through differential biological mixing of the soil. Whereas dissolution/ reprecipitation of the Fe cements is an important component of nodule formation, mobilised Fe reprecipitates locally. Dissolved Fe in the soil waters is almost entirely in the ferrous form. Vegetation type does not affect the concentration and speciation of Fe in soil waters, although Pinus DOM has greater acidic functional group site densities than DOM from native vegetation. Iron concentrations are highest in the high DOM soil waters collected from sandy podosols, where they are controlled by redox potential. Iron concentrations are low in soil solutions from clay and iron oxide rich soils, in spite of similar redox potentials. This is related to stronger sorption to the reactive clay and iron oxide mineral surfaces in these soils, which reduces the amount of DOM available for microbial metabolisation and reductive dissolution of Fe. Modelling suggests that Pinus DOM can significantly increase the amount of truly dissolved ferric iron remaining in solution in oxidising conditions. Thus, inputs of ferrous iron together with Pinus DOM to surface waters may reduce precipitation of hydrous ferric oxides and increase the flux of dissolved iron out of the catchment. Such inputs are most likely from the lower catchment, where podosols planted with Pinus are most widely distributed. Significant outcomes other than the main aims were also achieved. It is shown that mobilisation of Fe in podosols can occur as dissolved Fe(II) rather than as Fe(III)-organic complexes. This has implications for the large body of work which assumes that Fe(II) plays a minor role. Also, the first paper demonstrates that a data analysis approach based on Kohonen’s self organising maps can facilitate the interpretation of complex datasets and can help identify geochemical processes operating on a catchment scale.
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Fang, Zhufeng [Verfasser]. "3D hydrological simulation of a forested headwater catchment: Spatio-temporal validation and scale dependent parameterization / Zhufeng Fang." Bonn : Universitäts- und Landesbibliothek Bonn, 2016. http://d-nb.info/1119888891/34.
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Dutton, Anona L. "Process-based simulations of near-surface hydrologic response for a forested upland catchment: the impact of a road /." May be available electronically:, 2000. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Lin, Chaofeng. "Iron biogeochemistry and associated greenhouse gas evolution in a forested subtropical Australian coastal catchment : Poona Creek, Southeast Queensland." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/47072/1/Chaofeng_Lin_Thesis.pdf.
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Iron (Fe) is the fourth most abundant element in the Earth’s crust. Excess Fe mobilization from terrestrial into aquatic systems is of concern for deterioration of water quality via biofouling and nuisance algal blooms in coastal and marine systems. Substantial Fe dissolution and transport involve alternate Fe(II) oxidation followed by Fe(III) reduction, with a diversity of Bacteria and Archaea acting as the key catalyst. Microbially-mediated Fe cycling is of global significance with regard to cycles of carbon (C), sulfur (S) and manganese (Mn). However, knowledge regarding microbial Fe cycling in circumneutral-pH habitats that prevail on Earth has been lacking until recently. In particular, little is known regarding microbial function in Fe cycling and associated Fe mobilization and greenhouse (CO2 and CH4, GHG) evolution in subtropical Australian coastal systems where microbial response to ambient variations such as seasonal flooding and land use changes is of concern.
Using the plantation-forested Poona Creek catchment on the Fraser Coast of Southeast Queensland (SEQ), this research aimed to 1) study Fe cycling-associated bacterial populations in diverse terrestrial and aquatic habitats of a representative subtropical coastal circumneutral-pH (4–7) ecosystem; and 2) assess potential impacts of Pinus plantation forestry practices on microbially-mediated Fe mobilization, organic C mineralization and associated GHG evolution in coastal SEQ. A combination of wet-chemical extraction, undisturbed core microcosm, laboratory bacterial cultivation, microscopy and 16S rRNA-based molecular phylogenetic techniques were employed.
The study area consisted primarily of loamy sands, with low organic C and dissolved nutrients. Total reactive Fe was abundant and evenly distributed within soil 0–30 cm profiles. Organic complexation primarily controlled Fe bioavailability and forms in well-drained plantation soils and water-logged, native riparian soils, whereas tidal flushing exerted a strong “seawater effect” in estuarine locations and formed a large proportion of inorganic Fe(III) complexes. There was a lack of Fe(II) sources across the catchment terrestrial system. Mature, first-rotation plantation clear-felling and second-rotation replanting significantly decreased organic matter and poorly crystalline Fe in well-drained soils, although variations in labile soil organic C fractions (dissolved organic C, DOC; and microbial biomass C, MBC) were minor.
Both well-drained plantation soils and water-logged, native-vegetation soils were inhabited by a variety of cultivable, chemotrophic bacterial populations capable of C, Fe, S and Mn metabolism via lithotrophic or heterotrophic, (micro)aerobic or anaerobic pathways. Neutrophilic Fe(III)-reducing bacteria (FeRB) were most abundant, followed by aerobic, heterotrophic bacteria (heterotrophic plate count, HPC). Despite an abundance of FeRB, cultivable Fe(II)-oxidizing bacteria (FeOB) were absent in associated soils. A lack of links between cultivable Fe, S or Mn bacterial densities and relevant chemical measurements (except for HPC correlated with DOC) was likely due to complex biogeochemical interactions. Neither did variations in cultivable bacterial densities correlate with plantation forestry practices, despite total cultivable bacterial densities being significantly lower in estuarine soils when compared with well-drained plantation soils and water-logged, riparian native-vegetation soils.
Given that bacterial Fe(III) reduction is the primary mechanism of Fe oxide dissolution in soils upon saturation, associated Fe mobilization involved several abiotic and biological processes. Abiotic oxidation of dissolved Fe(II) by Mn appeared to control Fe transport and inhibit Fe dissolution from mature, first-rotation plantation soils post-saturation. Such an effect was not observed in clear-felled and replanted soils associated with low SOM and potentially low Mn reactivity. Associated GHG evolution post-saturation mainly involved variable CO2 emissions, with low, but consistently increasing CH4 effluxes in mature, first-rotation plantation soil only. In comparison, water-logged soils in the riparian native-vegetation buffer zone functioned as an important GHG source, with high potentials for Fe mobilization and GHG, particularly CH4 emissions in riparian loam soils associated with high clay and crystalline Fe fractions. Active Fe–C cycling was unlikely to occur in lower-catchment estuarine soils associated with low cultivable bacterial densities and GHG effluxes.
As a key component of bacterial Fe cycling, neutrophilic FeOB widely occurred in diverse aquatic, but not terrestrial, habitats of the catchment study area. Stalked and sheathed FeOB resembling Gallionella and Leptothrix were limited to microbial mat material deposited in surface fresh waters associated with a circumneutral-pH seep, and clay-rich soil within riparian buffer zones. Unicellular, Sideroxydans-related FeOB (96% sequence identity) were ubiquitous in surface and subsurface freshwater environments, with highest abundance in estuary-adjacent shallow coastal groundwater water associated with redox transition. The abundance of dissolved C and Fe in the groundwater-dependent system was associated with high numbers of cultivable anaerobic, heterotrophic FeRB, microaerophilic, putatively lithotrophic FeOB and aerobic, heterotrophic bacteria.
This research represents the first study of microbial Fe cycling in diverse circumneutral-pH environments (terrestrial–aquatic, freshwater–estuarine, surface–subsurface) of a subtropical coastal ecosystem. It also represents the first study of its kind in the southern hemisphere. This work highlights the significance of bacterial Fe(III) reduction in terrestrial, and bacterial Fe(II) oxidation in aquatic catchment Fe cycling. Results indicate the risk of promotion of Fe mobilization due to plantation clear-felling and replanting, and GHG emissions associated with seasonal water-logging. Additional significant outcomes were also achieved. The first direct evidence for multiple biomineralization patterns of neutrophilic, microaerophilic, unicellular FeOB was presented. A putatively pure culture, which represents the first cultivable neutrophilic FeOB from the southern hemisphere, was obtained as representative FeOB ubiquitous in diverse catchment aquatic habitats.
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Sabetraftar, Karim, and Karim Sabetraftar@anu edu au. "The hydrological flux of organic carbon at the catchment scale: a case study in the Cotter River catchment, Australia." The Australian National University. Centre for Resource and Environmental Studies, 2005. http://thesis.anu.edu.au./public/adt-ANU20070502.141450.
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Existing terrestrial carbon accounting models have mainly investigated atmosphere-vegetationsoil
stocks and fluxes but have largely ignored the hydrological flux of organic carbon. It is
generally assumed that biomass and soil carbon are the only relevant pools in a landscape
ecosystem. However, recent findings have suggested that significant amounts of organic carbon
can dissolve (dissolved organic carbon or DOC) or particulate (particulate organic carbon or
POC) in water and enter the hydrological flux at the catchment scale. A significant quantity of
total organic carbon (TOC) sequestered through photosynthesis may be exported from the
landscape through the hydrological flux and stored in downstream stocks.¶
This thesis presents a catchment-scale case study investigation into the export of organic carbon
through a river system in comparison with carbon that is produced by vegetation through
photosynthesis. The Cotter River Catchment was selected as the case study. It is a forested
catchment that experienced a major wildfire event in January 2003. The approach is based on an
integration of a number of models. The main input data were time series of in-stream carbon
measurements and remotely sensed vegetation greenness. The application of models to
investigate diffuse chemical substances has dramatically increased in the past few years because
of the significant role of hydrology in controlling ecosystem exchange. The research firstly
discusses the use of a hydrological simulation model (IHACRES) to analyse organic carbon
samples from stream and tributaries in the Cotter River Catchment case study. The IHACRES
rainfall-runoff model and a regionalization method are used to estimate stream-flow for the 75
sub-catchments. The simulated streamflow data were used to calculate organic carbon loads
from concentrations sampled at five locations in the catchment.¶
The gross primary productivity (GPP) of the vegetation cover in the catchment was estimated
using a radiation use efficiency (RUE) model driven by MODIS TERRA data on vegetation
greenness and modeled surface irradiance (RS). The relationship between total organic carbon
discharged in-stream and total carbon uptake by plants was assessed using a cross-correlation
analysis.¶
The IHACRES rainfall-runoff model was successfully calibrated at three gauged sites and
performed well. The results of the calibration procedure were used in the regionalization method
that enabled streamflow to be estimated at ungauged locations including the seven sampling
sites and the 75 sub-catchment areas. The IHACRES modelling approach was found appropriate
for investigating a wide range of issues related to the hydrological export of organic carbon at
the catchment scale. A weekly sampling program was implemented to provide estimates of
TOC, DOC and POC concentrations in the Cotter River Catchment between July 2003 and June
2004. The organic carbon load was estimated using an averaging method.¶
The rate of photosynthesis by vegetation (GPP) was successfully estimated using the radiation
use efficiency model to discern general patterns of vegetation productivity at sub-catchment
scales. This analysis required detailed spatial resolution of the GPP across the entire catchment
area (comprising 75 sub-catchment areas) in addition to the sampling locations. Important
factors that varied at the catchment scale during the sampling period July 2003 June 2004,
particularly the wildfire impacts, were also considered in this assessment.
¶
The results of the hydrologic modelling approach and terrestrial GPP outcome were compared
using cross correlation and regression analysis. This comparison revealed the likely proportion
of catchment GPP that contributes to in-stream hydrological flux of organic carbon. TOC Load
was 0.45% of GPP and 22.5 - 25% of litter layer. As a result of this investigation and giving due
consideration to the uncertainties in the approach, it can be concluded that the hydrological flux
of organic carbon in a forested catchment is a function of gross primary productivity.
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Ågren, Anneli. "Seasonal variation and landscape regulation of dissolved organic carbon concentrations and character in Swedish boreal streams." Doctoral thesis, Umeå universitet, Ekologi, miljö och geovetenskap, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1374.
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The seasonal variation and landscape regulation of dissolved organic carbon (DOC) concentrations in streams have been studied in two watersheds in the boreal zone. The seasonal variation was found to be highly correlated to variations in runoff. An increase in runoff was always accompanied with an increase in DOC concentration. However, there were indications that the TOC concentration was restricted by the soil TOC pool during snowmelt. The main factors affecting DOC exports varied between seasons. During winter baseflow the spatial variation in DOC exports was strongly influenced by wetland coverage, during snowmelt the exports were correlated to factors describing the size and location of the catchment, and during the snow-free season they were heavily affected by the proportions of wetlands and forests in the catchments. Small headwaters had the highest terrestrial DOC export, per unit area. The properties of the DOC changed during spring flood, towards lower molecular weight and more aliphatic compounds. These changes affected the bioavailability of the DOC, which increased during spring flood. There were also differences in the DOC properties between wetlands and forest soils; the forested soils yielded DOC with lower molecular weight (measured as 254 nm/365 nm light absorbance ratios), largely from superficial layers that were activated during high flow events, while wetland soils generally provided a more constant carbon source with higher molecular weight. The majority of the DOC was exported by wetlands, but most of the short-term bioavailable DOC (BP7) was derived from the forests, during the spring flood period, indicating that bacterial production in streams and lakes is likely to be almost entirely based on DOC exported from forested areas during, and some time after, the spring flood event.
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Hajian, Farhad. "Effects of land cover and climate changes on runoff and sediment yield from a forested catchment in northern Iran." Thesis, Kingston University, 2013. http://eprints.kingston.ac.uk/27011/.
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There have been more than 3700 recorded floods in Iran during the 50 years to around 2005, of which slightly more than half occurred during the final decade of this period. Over a longer period (1909-2004), floods in Iran caused economic losses in excess of US$3.5 billion. These floods, and associated erosion problems, have previously been attributed to land cover change and climate change. This research aimed to investigate future runoff changes in a small forested catchment in northern Iran for which appropriate and sufficient data exist to support such analyses. Approaches for estimating erosion and sediment production from the same catchment in the absence of relevant detailed data were also examined. The selected study site was the Casilian Catchment, with the town of Sangdeh at its centre. This is an elongated catchment approximately 17.8 km long with a mean catchment slope of 34.3% or 18.8°. The upstream half of the catchment is forested and, as such, could theoretically be susceptible to significant deforestation in the future. As such, it provides a suitable basis for the examination of hydrological implications – particularly runoff change – resulting from significant land cover change. To investigate the land cover change impact on runoff (volume and peak discharge of the outflow from the catchment), the approach used in this study was to use the Soil Conservation Service (SCS) curve number method with spatial catchment data using a Geographical Information System (GIS) and the SCS dimensionless unit hydrograph. The effects of rainfall characteristics and antecedent soil water content on runoff were also investigated. Runoff changes between observed period (1980-1986) and three different future periods (2011-2017, 2046-2052 and 2080-2086), for the Casilian Catchment, were estimated using the Hydrologic Engineering Centre-Hydrologic Modelling Systems (HEC-HMS) rainfall-runoff model. Thirteen climate models provided the required input variables (temperature, rainfall) to the rainfall-runoff model, under three different scenarios (A2, B1, and A1B) using the the ‘Long Ashton Research Station’ weather generator known as LARS-WG. This was used to downscale the Global Climate Model (GCM) to the Sangdeh Station to overcome the limitations of the coarse scale GCM output. Temperature was used to calculate potential evapotranspiration required for HMS rainfall-runoff model. The two empirical erosion models, known as the Erosion Potential Method (EPM) and Pacific South-West Inter-Agency Committee (PSIAC) methods, were evaluated to estimate sediment yield for the Casilian Catchment. Further, areas with high erosion intensity were identified, and factors affecting erosion were determined for the Casilian Catchment. In the EPM method, only three processes are used to prepare an erosion intensity map, but nine processes are considered in the PSIAC method. Runoff volume and the peak flow are considered to estimate erosion intensity and sediment yield in the PSIAC method, but not in the EPM method. Soil characteristics are also considered in erosion intensity and sediment yield estimation in the PSIAC method but not in the EPM method. The calculated mean annual specific sediment yield of the Casilian Catchment using the PSIAC method (482 t km-2yr-1) was closer to a measured value for the Talar Catchment (532 t km-2 y-1), of which Casilian is a subcatchment. Thus, the PSIAC-based erosion intensity map seems to be more representative of the erosion condition of the the Casilian Catchment. Slope, magnitude and intensity of rainfall, soil and land cover can be important factors affecting soil erosion of the Casilian Catchment. From this research, it was found that antecedent soil water content, magnitude and intensity of rainfall and the area affected by land cover change relative to the catchment size are important factors affecting runoff characteristics (volume of runoff and peak discharge). In the future, the mean rainfall totals (especially mean annual rainfall) and frequency of extreme rainfall events and rainfall intensity may increase due to an increase in atmospheric water vapour for the Casilian Catchment and probably other small catchments in northern Iran. Therefore, these catchments may be subjected to more flooding and erosion in the future as a result of changes in the rainfall characteristics. The findings of this research show that land cover change (e.g. deforestation and agricultural activities) should be given more consideration in the management of small catchments in northern Iran in the future, due to the consequences of climate change.
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加藤, 喜久雄, Kikuo KATO, 錦平 一柳, and Kimpei ICHIYANAGI. "森林流域における酸素安定同位体組成と主要成分濃度の変化について." 名古屋大学農学部付属演習林, 1996. http://hdl.handle.net/2237/8713.
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Bernhardsson, Malin. "Methylmercury in runoff from forested catchments : characterisation of three catchments prior to logging /." Uppsala : Sveriges lantbruksuniversitet, 2006. http://info1.ma.slu.se/IMA/Publikationer/internserie/2006-02.pdf.
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Spoelstra, John. "Nitrate sources and cycling at the Turkey Lakes Watershed: A stable isotope approach." Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/1240.
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Stable isotopic analysis of nitrate (15N/14N and 18O/16O) was used to trace nitrate sources and cycling under undisturbed conditions and following harvest at the Turkey Lakes Watershed (TLW), located near Sault Ste. Marie, Ontario, Canada.
Bulk precipitation collected biweekly at the TLW from 1995 to 2000 had nitrate isotope values that ranged from +42. 4 to +80. 4‰ for d18O and -6. 3 to +2. 8‰ for d15N. An incubation experiment indicated that the isotopic composition of atmospheric nitrate was not compromised by collection methods whereby unfiltered bulk precipitation samples remain in the collector for up to two weeks.
The first direct measurement of the isotopic composition of microbial nitrate produced in situ was obtained by eliminating precipitation inputs to three forest floor lysimeters and subsequently watering the area with a nitrate-free solution. Microbial nitrate had d18O values that ranged from +3. 1 to +10. 1‰ with a mean value of +5. 2‰, only slightly higher than values predicted based on the d18O-H2O of the watering solution used. d18O values of soil O2 (+23. 2 to +24. 1‰) down to a depth of 55cm were not significantly different from atmospheric O2 (+23. 5‰) and therefore respiratory enrichment of soil O2 did not affect the d18O values of microbial nitrate produced at the TLW.
Nitrate export from two undisturbed first-order stream basins was dominated by microbial nitrate, with the contribution of atmospheric nitrate peaking at about 30% during snowmelt. Clear-cutting of catchment 31 in 1997 resulted in elevated nitrate concentrations, reaching levels that exceeded the drinking water limit of 10 mg N/L. Isotopic analysis indicated that the source of this nitrate was predominantly chemolithoautotrophic nitrification. The d18O values of microbial nitrate in stream 31 progressively increased during the post-harvest period due to an increase in the proportion of nitrification that occurred in the summer months. Despite drastic alteration of nitrogen cycling in the catchment by the harvest, d15N-nitrate values in shallow groundwater did not change from the pre-harvest. Denitrification and plant uptake of nitrate in a small forested swamp in catchment 31 attenuated 65 to 100% of surface water nitrate inputs following harvest, reducing catchment-scale nitrate export by 35 to 80%.
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Donnelly, Lauren. "Comparison of rainfall-runoff modelling techniques in small forested catchments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq24122.pdf.
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Hill, Timothy. "Dynamic modelling and analysis of hydrochemistry in upland forested catchments." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340078.
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Rawlins, Barry Gordon. "The hydrochemistry of an acid, coniferous forest soil : (Grizedale forest, Cumbria, U.K.)." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284388.
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Katsuyama, Masanori. "Study on hydrochemical dynamics of groundwater and streamwater in forested headwater catchments." Kyoto University, 2002. http://hdl.handle.net/2433/59287.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第9653号
農博第1281号
新制||農||848(附属図書館)
学位論文||H14||N3685(農学部図書室)
UT51-2002-G411
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 谷 誠, 教授 三野 徹, 教授 水山 高久
学位規則第4条第1項該当
20
Uchida, Taro. "Effects of Pipeflow on Storm Runoff Generation Processes at Forested Headwater Catchments." Kyoto University, 2000. http://hdl.handle.net/2433/181041.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第8412号
農博第1096号
新制||農||797(附属図書館)
学位論文||H12||N3369(農学部図書室)
UT51-2000-F316
京都大学大学院農学研究科森林科学専攻
(主査)教授 水山 高久, 教授 谷 誠, 教授 吉田 博宣
学位規則第4条第1項該当
21
Abu-Maila, Y. S. "Geomorphic and hydrologic processes in Coombs Brook, Macclesfield Forest." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378012.
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Kawasaki, Masatoshi. "Hydrological and biogeochemical controls on dissolved organic carbon dynamics in forested headwater catchments." Kyoto University, 2005. http://hdl.handle.net/2433/145023.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第11622号
農博第1478号
新制||農||906(附属図書館)
学位論文||H17||N4015(農学部図書室)
23265
UT51-2005-D371
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 谷 誠, 教授 小﨑 隆, 教授 太田 誠一
学位規則第4条第1項該当
23
Biederman, Joel Aaron. "Coupled Hydrologic and Biogeochemical Response to Insect-Induced Forest Disturbance." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311213.
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Forest disturbance is expanding in rate and extent and is affecting many montane catchments critical to water resources. Western North America is experiencing an epidemic of mountain pine beetle (MPB) that has affected 20 million hectares of forest in Canada and the United states. This epidemic may have long-lasting consequences for coupled cycles of water, energy, and biogeochemicals. While impacts of forest disturbance by fire and harvest have been studied for more than a half-century, insect-driven mortality differs from these events in the timing and accompanying biophysical impacts. In this work, we quantified catchment hydrologic and hydrochemical response to severe MPB infestation in a lodgepole pine ecosystem. Observations were organized laterally in a nested fashion from soil observations to nested headwater catchments. Vertical observations encompassed what is often termed the critical zone, from atmospheric interactions at the top of the forest through the ground surface and the rooting zone to the interface with groundwater. We quantified responses manifest in snowpack, the primary hydrologic input to this montane ecosystem, in water partitioning between vapor flux and streamflow, and in biogeochemical patterns across the landscape. Key findings of this study include 1) Loss of shelter from the atmosphere caused compensatory sublimation of snowpack to offset decreased interception losses after MPB-driven canopy loss; 2) Vaporization at multiple scales increased over time and in comparison to control forest, reducing water available for streamflow; 3) Nitrogen (N) concentrations were elevated in hillslope groundwater, but attenuation in the riparian zone protected streams from major N influx; and 4) headwater streams rapidly attenuated dissolved carbon (C) and N inputs. Collectively these results demonstrate compensatory negative feedbacks which help explain the lack of strong response to streamflow and stream chemistry observed in the recent MPB epidemic.
24
Fölster, Jens. "Catchment hydrochemical processes controlling acidity and nitrogen in forest stream water /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-6074-3.pdf.
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Sørensen, Rasmus. "Influence of topography and forestry on catchments : soil properties, runoff regime, and mercury outputs /." Uppsala : Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200985.pdf.
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López, Tarazón José Andrés. "The sediment budget of a highl y erodible catchment. The river Isábena (Ebro basin, central pyrennes)." Doctoral thesis, Universitat de Lleida, 2011. http://hdl.handle.net/10803/21774.
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Huntress, David William. "Chemical Dynamics During High Discharge Events at Three Forested Catchments in Eastern Maine, USA." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/HuntressDW2008.pdf.
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Fujimoto, Masamitsu. "Effects of hillslope topography and bedrock groundwater dynamics on runoff generation in forested headwater catchments." Kyoto University, 2008. http://hdl.handle.net/2433/136595.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第13868号
農博第1683号
新制||農||953(附属図書館)
学位論文||H20||N4335(農学部図書室)
UT51-2008-C784
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 谷 誠, 教授 小﨑 隆, 教授 水山 高久
学位規則第4条第1項該当
29
Elsenbeer, Helmut, Keith Cassel, and Jorge Castro. "Spatial analysis of soil hydraulic conductivity in a tropical rain forest catchment." Universität Potsdam, 1992. http://opus.kobv.de/ubp/volltexte/2008/1697/.
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The topography of first-order catchments in a region of western Amazonia was found to exhibit distinctive, recurrent features: a steep, straight lower side slope, a flat or nearly flat terrace at an intermediate elevation between valley floor and interfluve, and an upper side slope connecting interfluve and intermediate terrace. A detailed survey of soil-saturated hydraulic conductivity (K sat)-depth relationships, involving 740 undisturbed soil cores, was conducted in a 0.75-ha first-order catchment. The sampling approach was stratified with respect to the above slope units. Exploratory data analysis suggested fourth-root transformation of batches from the 0–0.1 m depth interval, log transformation of batches from the subsequent 0.1 m depth increments, and the use of robust estimators of location and scale. The K sat of the steep lower side slope decreased from 46 to 0.1 mm/h over the overall sampling depth of 0.4 m. The corresponding decrease was from 46 to 0.1 mm/h on the intermediate terrace, from 335 to 0.01 mm/h on the upper side slope, and from 550 to 0.015 mm/h on the interfluve. A depthwise comparison of these slope units led to the formulation of several hypotheses concerning the link between K sat and topography.
30
Itoh, Masayuki. "Hydrological and biogeochemical controls on methane dynamics in a temperate forest catchment." Kyoto University, 2007. http://hdl.handle.net/2433/136537.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第13118号
農博第1623号
新制||農||941(附属図書館)
学位論文||H19||N4244(農学部図書室)
UT51-2007-H391
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 谷 誠, 教授 武田 博清, 教授 小﨑 隆
学位規則第4条第1項該当
31
Kim, Su-Jin. "Hydro-Biogeochemical Study on the Sulfur Dynamics in a Temperate Forest Catchment." Kyoto University, 2003. http://hdl.handle.net/2433/148320.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第10500号
農博第1373号
新制||農||881(附属図書館)
学位論文||H15||N3855(農学部図書室)
UT51-2003-U470
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 谷 誠, 教授 武田 博清, 教授 東 順一
学位規則第4条第1項該当
32
Hultin, Eriksson Elin. "Quantification of Terrestrial CO2 Sources to a Headwater Streamin a Boreal Forest Catchment." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-305435.
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Carbon Dioxide (CO2) emissions from streams are a significant component of the global carbon cycle.Terrestrial export of CO2 through runoff is increasingly recognized as a major source of CO2 in boreal headwater streams. However, the spatial and temporal distribution of soil water CO2 within theterrestrial landscape remains poorly quantified, contributing to large uncertainties about the origin of CO2 in headwater streams. The riparian zone (i.e. the area with fine sediments and organic rich soils closest to the stream) is accepted as a main contributor of organic carbon to streams, but its importanceas a source of CO2 is less evident. Here I evaluate the riparian zone as a main source by quantifying the contribution of lateral CO2 export from the riparian and hillslope zones to a headwater stream in a Swedish boreal catchment. Hourly measurements of CO2 concentration, conductivity, soil temperature and water table levels were taken in the riparian zone and the hillslope from June 2014 to October 2015. The riparian zone accounted for 58-89 % (August 2014 and March respectively) of the total terrestrial CO2 export from the slope to the stream. The hillslope, in turn, became a progressively larger source of CO2 to the stream during high flow events. To identify the drivers behind these zone-dependent and seasonal patterns in CO2 export, the CO2 production dissolved in the groundwater (groundwater- absorbed carbon) was estimated by taking the temporarily stored CO2 into account. The highest groundwater-absorbed carbon was observed during April and May (5.0 and 7.1 g C-CO2 m-2 month-1 respectively) which is the period with the highest discharge due to snow melt and the initiation of spring production. As such, conventional methods (gas chambers and the gradient method) may underestimate the soil respiration up to 50% during periods of high flow, as they exclude groundwater-absorbed carbon. CO2 consumption was observed in September 2014 and October 2015 (-0.2 and -0.7 g C-CO2 m-2 month-1 respectively) and may be explained by a major amount of the soil respiration being emitted instead of diluted in the groundwater during periods of low groundwater levels. It can be concludedthat, regardless of season, the riparian zone is a major source of CO2 to the headwater stream.En signifikant mängd koldioxid (CO2) är lagrad i skog och marken. Marken i barrskogsregionernaförvarar en signifikant mängd CO2 där det partiella trycket av CO2 varierar mellan ~10 000 – 50 000 ppm i jämförelse med atmosfären (400 ppm). Mättnaden av CO2 gör att mycket avdunstar tillbaka till atmosfären. Dock absorberas en del CO2 av grundvattnet; vilket resulterar i en naturlig transport av CO2 vidare till ytvattnen där det kapillära nätverket av bäckar är största recipienten. Det är fortfarande oklart hur transporten av CO2 är distribuerad i ett vattenavrinningsområde vilket medför brister i förståelsen av en viktig processväg som kan komma att spela en större roll i framtidens kolkretslopp på grund av den globala uppvärmningen. Därför är en kvantifiering av olika områdens bidrag av CO2 till bäckarna nödvändig. Två betydande zoner i ett vattenavrinningsområde som troligen bidrar olika är: the riparian zone som är närmast bäcken och består av fina sediment med hög organisk halt och, the hillslope som är resterande område och består av grovkorniga jordar med låg organisk halt. Den förstnämnda misstänks transportera mer CO2 via grundvattnet på grund av dess närhet till bäcken, höga halter av CO2 och höga vattenmättnad men detta är ännu inte verifierat. Jag evaluerar the riparian zone som en viktig källa till CO2 i ett vattenavrinningsområde genom att kvantifiera transporten av CO2 från de två zonerna. För att förklara varför transporten varierar presenterar jag en ny modell (GVR) som beräknar den månatliga fluktuationen av den del av CO2-produktionen som absorberas i grundvattnet i the riparian zone. Mätningar av data utfördes i Västrabäcken, ett mindre vattenavrinningsområde i ett större vid namn Krycklan, i norra Sverige. En transekt av tre mätstationer (i bäcken, the riparian zone och the hillslope) installerades i den förmodade grundvattenströmningsriktningen. Resultaten visar på en hög produktion av CO2 under vårfloden (maj) då en hög grundvattenyta troligen absorberar en signifikant mängd CO2. Detta kan betyda att jordrespiration under våren underskattas då dagens mätmetoder är begränsade till mätningar i jorden av CO2 ovan grundvattenytan. Fortsatta studier rekommenderas där GVR-modellen och andra mätmetoder utförs samtidigt för att vidare utröna den kvantitativa underskattningen under perioder med hög grundvattenyta (speciellt under våren). Bidraget från the riparian zone till den totala laterala transporten av CO2 till bäcken under ett år varierar mellan 58-89 % och det månatliga transportmönstret kunde förklaras med resultaten från GVR-modellen. Resultaten verifierar att oberoende av säsong så är the riparian zone den huvudsakliga laterala koltransporten från landvegetationen; medan the hillslope procentuellt bidrar med mer CO2 under höga grundvattenflöden.
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Noguchi, Shoji. "Hydrological characteristics of a small catchment in a tropical rain forest, Peninsular Malaysia." Kyoto University, 2001. http://hdl.handle.net/2433/150352.
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Mieres, Dinamarca Francisco. "Production, sorption and pathways for dissolved organic carbon flow in the Krycklan catchment. : Modelling with focus on the terrestrial forest ecosystem." Thesis, KTH, Mark- och vattenteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190613.
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Dissolved Organic Carbon accounts for many different functions in the boreal forest ecosystem. It is the main vehicle for organic carbon transport from the litterfall to the forest soil profile and together with water drainage it can be transported to streams. In boreal forests, the DOC transport have gain attention because of recently documented rise in concentration. Several models have been proposed, first to gain understanding in the main cauces of this increase in concentration, and then to simulate the transport of DOC in the landscape. An exploratory work was made to identify the extent of physical control and hydrological pathways for DOC discharge and the long-term biological control over DOC production, transport in the soil profile and discharge in 2 different situations. A 22-year dataset from the Krycklan Catchment site was used. Meteorological data was used as driving variables to calibrate DOC concentration and runoff in a small catchment (Site C7). The CoupModel was set up to represent the described vegetation and documented soil characterization and then calibrated to fit the measured variables. A stepwise calibration process was preferred to promote the understanding of the different components of the landscape in the organic carbon cycle. Results point to soil heat and water transfer processes as the most relevant group to explain both water runnof and DOC discharge, with increasing relevance in the deeper layers, explaining up to 97% of short-term variability in DOC discharge for the 27-35 cm layer. Soil organic carbon pools showed to have relevance in organic carbon stock balance along the soil profile. Conclusions state that, In concordance with other authors, there is a hydrological primary control over DOC discharge, but that soil organics and especially vegetation perform a relevant role in long-term balance of the organic carbon cycle. Further studies with this model could include time-series of atmospheric deposition of Sulphur and nitrogen and running the model in cascade.
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Panta, Sita. "Effects of thinning on forest structure and composition in the Wungong catchment, Western Australia." Thesis, Panta, Sita (2012) Effects of thinning on forest structure and composition in the Wungong catchment, Western Australia. Masters by Research thesis, Murdoch University, 2012. https://researchrepository.murdoch.edu.au/id/eprint/6747/.
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The focus of jarrah (Eucalyptus marginata Donn ex. Smith) forest management in past decades has been changing in response to forest management practices of the day, interests and needs of the forest users and more recently a changing climate. Following uncontrolled logging including clear-felling and wild-fires after European settlement (1830s onwards) and rotational logging and burning under the state forest management plan, much of the old growth forest of south-west Western Australia has been converted into a dense re-growth forest. Substantial reduction in the rainfall in the south-west of Western Australia in the past three decades has resulted in a significant decrease in water available to the Integrated Water Supply Scheme at a time of increasing water demand of the region. A forest thinning trial to increase both water yield and environmental benefits from the catchment has been implemented since 2006 in the Wungong Catchment within state forest. Wungong forest is now managed by the Water Corporation as a drinking water catchment in association with the Department of Environment and Conservation (DEC) and Forest Product Commission (FPC); and is under the scrutiny of Environmental Protection Authority (EPA) of Western Australia. Although the effects of forest thinning on catchment hydrology are well understood, short-term effects of thinning on forest ecosystems especially on forest structure and composition are less well understood. The research reported in this thesis contributes to understanding the short-term effects of thinning on stand structure and on the composition of overstorey and understorey components of the forest, including the dead woody debris (DWD).
Two thinning strategies, i.e., commercial logging followed by glyphosate herbicide treatment of selected non-commercial trees (log+notch) or killing of selected trees by applying glyphosate herbicide to notches in the trunk (notch-only), were compared as treatments to the adjacent unthinned stands (control) in the Wungong Catchment within jarrah forest of south-west Western Australia. All three treatments were replicated three times using plots of 90 x 70 m size. Thinning, which was carried out in September, 2009, reduced tree basal area from 50.2 to 17.9 m2 ha-1 for log+notch and 43.8 to 22.2 m2 ha-1 for notch-only treatment.
Forest structure variables were investigated in relation to thinning viz: stand density and basal area for three dominant tree species and their composition in the overstorey; understorey species richness and ground cover; and quantity, structure and composition of DWD.
This study revealed that both log+notch and notch-only thinning treatments significantly reduced the overall stand density and basal area and changed the composition of the treated tree stands compared to the unthinned stands. Frequency distributions of the tree stands in different size classes were altered with highly significant decreases in 20-30 and 30-40 cm diameter at breast height (DBH) classes. By contrast, no significant effect was observed in the understorey species richness and ground cover within 1 year after thinning, partly due to the absence of direct physical disturbance in the sampled quadrats. However, there was a slight reduction in thinned as well as control forest in the species richness recorded during the hot and dry season compared to the winter sampling. Results suggest that selection of sampling units representing different micro-site conditions within the study area are important and the sampling area needs to be increased to 64 m2 (16 lots of 2x2 m quadrats) to adequately represent species richness present in the study area.
Thinning increased the quantity of DWD by 100 % in log+notch and 142 % in notch-only treatments. Thinning also changed the structure and composition of DWD components (i.e. log, snag and stump) by altering the percentage contribution of each component to the total DWD pool. Thinning altered the percentage contribution of log, snag and stump components to the total DWD volume from 80, 17 and 3 % before thinning to 48, 50 and 2 %, respectively, for log+notch treatment after 1 year, and from 86, 11 and 2 % to 36, 63 and 1 %, respectively, for notch-only treatments. Changes in the structure of the dead woody resources after thinning revealed that the amount, structure and composition of DWD in the forested catchment was directly related to stand age and structure of the living trees and more specifically to the method and intensity of forest thinning.
In summary, this study suggests that thinning as a management intervention is an important driver of the structure and composition dynamics of jarrah forest ecosystems. The level of reduction in the stand density and basal area of the tree stand and increase in the amount of DWD as compared to the adjacent control stands were dependent on the methods and intensity of thinning. Although the effects of thinning on overstorey components such as species composition, stand density and diameter size-class distribution of tree stands, and on DWD components were significant, effects on understorey species richness and ground cover were not discernable in the short-term. Hence, longer term study of post-thinning vegetation structure and composition are needed to adequately describe thinning impacts on postthinning vegetation dynamics and successional processes
36
Stott, Timothy Alan. "Forestry effects on sediment sources and yields in the Balquhidder catchments, central Scotland." Thesis, University of Stirling, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359683.
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Vieira, Diana Catarina Simões. "Understanding and modelling hydrological and soil erosion processes in burnt forest catchments." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14470.
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Doutoramento em Ciências e Engenharia do AmbienteForest fires implications in overland flow and soil erosion have been researched for several years. Therefore, is widely known that fires enhance hydrological and geomorphological activity worldwide as also in Mediterranean areas. Soil burn severity has been widely used to describe the impacts of fire on soils, and has being recognized as a decisive factor controlling post-fire erosion rates. However, there is no unique definition of the term and the relationship between soil burn severity and post-fire hydrological and erosion response has not yet been fully established. Few studies have assessed post-fire erosion over multiple years, and the authors are aware of none which assess runoff. Small amount of studies concerning pre-fire management practices were also found. In the case of soil erosion models, the Revised Universal Soil Loss Equation (RUSLE) and the revised Morgan–Morgan–Finney (MMF) are well-known models, but not much information is available as regards their suitability in predicting post-fire soil erosion in forest soils. The lack of information is even more pronounced as regards post-fire rehabilitation treatments. The aim of the thesis was to perform an extensive research under the post fire hydrologic and erosive response subject. By understanding the effect of burn severity in ecosystems and its implications regarding post fire hydrological and erosive responses worldwide. Test the effect of different pre-fire land management practices (unplowed, downslope plowed and contour plowed) and time-since-fire, in the post fire hydrological and erosive response, between the two most common land uses in Portugal (pine and eucalypt). Assess the performance of two widely-known erosion models (RUSLE and Revised MMF), to predict soil erosion rates during first year following two wildfires of distinctive burn severity. Furthermore, to apply these two models considering different post-fire rehabilitation treatments in an area severely affected by fire. Improve model estimations of post-fire runoff and erosion rates in two different land uses (pine and eucalypt) using the revised MMF. To assess these improvements by comparing estimations and measurements of runoff and erosion, in two recently burned sites, as also with their post fire rehabilitation treatments. Model modifications involved: (1) focusing on intra-annual changes in parameters to incorporate seasonal differences in runoff and erosion; and (2) inclusion of soil water repellency in runoff predictions. Additionally, validate these improvements with the application of the model to other pine and eucalypt sites in Central Portugal. The review and meta-analysis showed that fire occurrence had a significant effect on the hydrological and erosive response. However, this effect was only significantly higher with increasing soil burn severity for inter-rill erosion, and not for runoff. This study furthermore highlighted the incoherencies between existing burn severity classifications, and proposed an unambiguous classification. In the case of the erosion plots with natural rainfall, land use factor affected annual runoff while land management affected both annual runoff and erosion amounts significantly. Time-since-fire had an important effect in erosion amounts among unplowed sites, while for eucalypt sites time affected both annual runoff and erosion amounts. At all studied sites runoff coefficients increase over the four years of monitoring. In the other hand, sediment concentration in the runoff, recorded a decrease during the same period. Reasons for divergence from the classic post-fire recovery model were also explored. Short fire recurrence intervals and forest management practices are viewed as the main reasons for the observed severe and continuing soil degradation. The revised MMF model presented reasonable accuracy in the predictions while the RUSLE clearly overestimated the observed erosion rates. After improvements: the revised model was able to predict first-year post-fire plot-scale runoff and erosion rates for both forest types, these predictions were improved both by the seasonal changes in the model parameters; and by considering the effect of soil water repellency on the runoff, individual seasonal predictions were considered accurate, and the inclusion of the soil water repellency in the model also improved the model at this base. The revised MMF model proved capable of providing a simple set of criteria for management decisions about runoff and erosion mitigation measures in burned areas. The erosion predictions at the validation sites attested both to the robustness of the model and of the calibration parameters, suggesting a potential wider application.
As implicações dos fogos florestais na escorrência superficial e erosão dos solos têm sido objeto de estudo desde há vários anos. Como tal, é do conhecimento geral, que os fogos tendem a aumentar a atividade hidrológica e geomorfológica em todo o mundo e também nas zonas mediterrânicas. A severidade da queima do solo tem sido utilizada para descrever o impacto dos fogos nos solos e reconhecida como um fator decisivo no controle das taxas de erosão pós-fogo. No entanto, não existe uma definição única do termo e a relação entre severidade de queima do solo com a resposta hidrológica e erosiva não é ainda totalmente conhecida. Por outro lado, escasseiam os estudos com registos de taxas de erosão pós-fogo durante um período de quatro anos, nenhum dentro desse período com registos de escorrência superficial pós-fogo. Menos estudos ainda, que retratem a resposta erosiva pós-fogo, mencionando práticas de gestão florestal anteriores ao mesmo. No caso da modelação de erosão dos solos, apesar dos modelos aplicados ‒ a Equação Universal de Perdas do Solo Revista (RUSLE) e o modelo de Morgan-Morgan-Finney (MMF) ‒ serem bem conhecidos, a informação referente à sua aplicabilidade para prever taxas de erosão em solos florestais após o fogo é bastante limitada. No caso da aplicabilidade destes modelos, considerando tratamentos de mitigação após incêndio, ainda menos informação existe. O objetivo deste trabalho é o aprofundar do conhecimento relativo à resposta hidrológica e erosiva após incêndios florestais através do estudo dos efeitos da severidade de queima nos ecossistemas e das suas implicações na resposta hidrológica e erosiva em todo o mundo. Para este fim, testámos também o efeito de diferentes práticas de gestão florestal (não lavrado, lavrado no sentido do declive e lavrado segundo as curvas de nível), executadas previamente ao incêndio florestal, entre dois dos usos do solo mais comuns em Portugal: o pinheiro e o eucalipto. Testámos ainda a eficiência com que dois modelos, amplamente conhecidos (RUSLE e MMF revisto), conseguem prever, em duas severidades distintas e com tratamentos de reabilitação pós fogo, as taxas de erosão durante o ano que seguiu ao incêndio florestal. Com essa informação, que veio melhorar as estimativas, alterámos o modelo e verificámos a sua eficiência, tanto nas previsões de escorrência superficial como na erosão do solo em pós-fogo e em pós-fogo com tratamentos de reabilitação. Essas alterações, que consistiam em (1) passar todos os inputs numa escala sazonal para incorporar as variações sazonais sentidas na formação de escorrência superficial e erosão do solo, e (2) inclusão do efeito hidrófobo do solo à água nas previsões da escorrência superficial. Adicionalmente, validar estas melhorias noutra área florestal independente no centro de Portugal para pinhal e eucaliptal, pós-fogo e pós-fogo com tratamentos de reabilitação. A revisão e a meta-análise demonstraram que a ocorrência de um fogo florestal provoca alterações significativas na resposta hidrológica e erosiva. No entanto, este efeito só é significativamente diferente com o aumento da severidade da queima do solo para a erosão e não para a geração de escorrência superficial. Este estudo também aludiu a incoerência entre várias classificações de severidade de queima e propõe ainda uma classificação não ambígua. No caso das parcelas de erosão com chuva natural, verificou-se que o uso do solo é um fator que afeta a geração de escorrência; em contrapartida, a gestão florestal afeta tanto a escorrência como a erosão do solo. O tempo decorrido desde o incêndio surge como fator de elevada importância entre locais não lavrados, relativamente às perdas de solo, e entre eucaliptais, relativamente à escorrência e erosão. Em todos os locais os coeficientes de escorrência aumentaram do primeiro para o quarto ano de estudo. Noutra nota, notou-se um decréscimo nas concentrações de sedimentos na escorrência durante o mesmo período. Foi explorada a discrepância entre este estudo e entre os modelos clássicos de recuperação pós-fogo; também o curto intervalo entre fogos e as constantes práticas de gestão florestal são vistas como as principais razões pela severa e continuada degradação dos solos. O modelo de MMF revisto apresentou uma razoável acuidade nas previsões enquanto que, o RUSLE claramente sobrestimou as taxas de erosão observadas. Ambos os modelos demonstraram capacidades para serem usados como ferramentas operacionais para ajudarem gestores a determinar áreas de risco de erosão pós-fogo e a tomarem ações prioritárias. O Modelo MMF revisto permitiu determinar as taxas de erosão durante o primeiro ano, após o fogo, para os dois usos do solo estudados: o pinheiro e o eucalipto. Essas previsões melhoraram com a implementação da modelação sazonal e com a inclusão da hidrofobia do solo à água para as previsões de escorrência. Por fim, o modelo de MMF revisto provou ser capaz de providenciar um conjunto de critérios para ajudar à tomada de decisões por parte dos gestores relativamente à escorrência, erosão e tratamentos de mitigação em áreas recentemente ardidas. Este modelo sugere, segundo os resultados obtidos aquando da validação e calibração, uma elevada robustez e um potencial de ser aplicado a outras áreas.
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Mohr, Christian Heinrich. "Hydrological and erosion responses to man-made and natural disturbances : insights from forested catchments in South-central Chile." Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2014/7014/.
Full textAbstract:
Logging and large earthquakes are disturbances that may significantly affect hydrological and erosional processes and process rates, although in decisively different ways. Despite numerous studies that have documented the impacts of both deforestation and earthquakes on water and sediment fluxes, a number of details regarding the timing and type of de- and reforestation; seismic impacts on subsurface water fluxes; or the overall geomorphic work involved have remained unresolved. The main objective of this thesis is to address these shortcomings and to better understand and compare the hydrological and erosional process responses to such natural and man-made disturbances. To this end, south-central Chile provides an excellent natural laboratory owing to its high seismicity and the ongoing conversion of land into highly productive plantation forests.
In this dissertation I combine paired catchment experiments, data analysis techniques, and physics-based modelling to investigate: 1) the effect of plantation forests on water resources, 2) the source and sink behavior of timber harvest areas in terms of overland flow generation and sediment fluxes, 3) geomorphic work and its efficiency as a function of seasonal logging, 4) possible hydrologic responses of the saturated zone to the 2010 Maule earthquake and 5) responses of the vadose zone to this earthquake.
Re 1) In order to quantify the hydrologic impact of plantation forests, it is fundamental to first establish their water balances. I show that tree species is not significant in this regard, i.e. Pinus radiata and Eucalyptus globulus do not trigger any decisive different hydrologic response. Instead, water consumption is more sensitive to soil-water supply for the local hydro-climatic conditions.
Re 2) Contradictory opinions exist about whether timber harvest areas (THA) generate or capture overland flow and sediment. Although THAs contribute significantly to hydrology and sediment transport because of their spatial extent, little is known about the hydrological and erosional processes occurring on them. I show that THAs may act as both sources and sinks for overland flow, which in turn intensifies surface erosion. Above a rainfall intensity of ~20 mm/h, which corresponds to <10% of all rainfall, THAs may generate runoff whereas below that threshold they remain sinks. The overall contribution of Hortonian runoff is thus secondary considering the local rainfall regime. The bulk of both runoff and sediment is generated by Dunne, saturation excess, overland flow. I also show that logging may increase infiltrability on THAs which may cause an initial decrease in streamflow followed by an increase after the groundwater storage has been refilled.
Re 3) I present changes in frequency-magnitude distributions following seasonal logging by applying Quantile Regression Forests at hitherto unprecedented detail. It is clearly the season that controls the hydro-geomorphic work efficiency of clear cutting. Logging, particularly dry seasonal logging, caused a shift of work efficiency towards less flashy and mere but more frequent moderate rainfall-runoff events. The sediment transport is dominated by Dunne overland flow which is consistent with physics-based modelling using WASA-SED.
Re 4) It is well accepted that earthquakes may affect hydrological processes in the saturated zone. Assuming such flow conditions, consolidation of saturated saprolitic material is one possible response. Consolidation raises the hydraulic gradients which may explain the observed increase in discharge following earthquakes. By doing so, squeezed water saturates the soil which in turn increases the water accessible for plant transpiration. Post-seismic enhanced transpiration is reflected in the intensification of diurnal cycling.
Re 5) Assuming unsaturated conditions, I present the first evidence that the vadose zone may also respond to seismic waves by releasing pore water which in turn feeds groundwater reservoirs. By doing so, water tables along the valley bottoms are elevated thus providing additional water resources to the riparian vegetation. By inverse modelling, the transient increase in transpiration is found to be 30-60%. Based on the data available, both hypotheses, are not testable.
Finally, when comparing the hydrological and erosional effects of the Maule earthquake with the impact of planting exotic plantation forests, the overall observed earthquake effects are comparably small, and limited to short time scales.Landmanagement und tektonische Prozesse haben einen erheblichen Einfluss auf das Abflussverhalten und den Wasser-, sowie den Sedimenthaushalt von Gebirgsregionen. Sowohl forstwirtschaftliche Bewirtschaftung, als auch starke Erdbeben sind Impulse, die hydrologische und Erosionsprozesse, sowie deren Prozessraten beeinflussen. Obwohl zahlreiche Arbeiten bereits den Einfluss von forstlicher Bewirtschaftung (Abholzungen, Aufforstungen) als auch von Erdbeben auf Wasser und Sedimentflüsse dokumentiert haben, bleiben wichtige Fragen offen. Wie entscheidend ist der Zeitpunkts der Abholzung und des nachfolgenden Wiederaufforstens? Wie wirken seismische Störungen auf unterirdische Wasserflüsse? Wie ändert sich die geomorphologische Arbeit nach Kahlschlägen? Zur Erforschung dieser Fragen bietet sich das südliche Zentralchile aufgrund seiner hohen lokalen seismischen Aktivität und der kontinuierlichen Umwidmung von Flächen in hochproduktive Plantagenwälder hervorragend an. Letztere verursachen sich häufig verändernde Umweltbedingungen durch kurze forstwirtschaftliche Rotationszyklen. Diese Dissertation betrachtet Einzugsgebiete mit vergleichbarer naturräumlicher Ausstattung. Dabei werden experimentelle Datenerhebung, ein Monitoring-Programm und Datenanalysetechniken mit prozessbasierter Modellierung kombiniert. Ziel der vorliegenden Arbeit ist: 1) die Untersuchung des Einflusses von Plantagenwäldern auf den lokalen Wasserhaushalt. Hier zeigt sich, dass die Baumart (Pinus radiata vs. Eucalyptus globulus) keinen entscheidenden Einfluss auf die lokale Wasserbilanz hat. Vielmehr ist der Bodenwasserspeicher unter dem gegebenen lokalen Hydroklima der entscheidende Faktor für den Wasserverbrauch. 2) die Untersuchung des Verhaltens von Kahlschlagflächen im Hinblick auf Quellen oder Senkenwirkung für Oberflächenabfluss und Sedimenttransport. Hier zeigt sich, dass diese Flächen sowohl als Quelle als auch als Senke für Oberflächenabfluss und Sedimenttransport wirken können – abhängig von der Regenintensität. Übersteigt diese ~20 mm/h, was <10 % der lokalen Niederschlagsereignisse entspricht, generieren Kahlschlagflächen Horton-Oberflächenabfluss (Infiltrationsüberschuss) und Sedimenttransport. Unterhalb dieses Schwellenwerts wirken sie als Senke. In Anbetracht der lokalen Niederschlagintensitäten ist der Gesamtbeitrag des Horton-Oberflächenabflusses daher sekundär. Der Großteil des Abflusses entsteht durch Dunne-Oberflächenabfluss (Sättigungsüberschuss). Zudem zeigt die vorliegende Arbeit, dass Abholzen die Infiltrabilität erhöhen kann. Dies führte dazu, dass zunächst der Gebietsabfluss abfällt bevor er erst nach Auffüllen des Grundwasserspeichers signifikant ansteigt. 3) Die Untersuchung des Einflusses von Kahlschlägen auf die hydro-geomorphologische Arbeit und ihre Effizienz. Durch das Anwenden von Quantile Regression Forests (QRF) wird auf kurzer Prozessskala gezeigt, dass Abholzung zu unterschiedlicher Jahreszeit zu signifikanten Veränderungen im Sedimenttransport führt. Vor allem Kahlschläge die während der Trockenzeit durchgeführt werden, verursachten einen Bedeutungsverlust von seltenen, stärkeren Abflussereignissen zu Gunsten der häufigeren, jedoch weniger starken Ereignissen. Hierbei dominierte der Dunne-Oberflächenabfluss. Dies stimmt mit den Ergebnissen eines prozessbasierten hydrologischen Modells (WASA-SED) überein. Es ist somit eindeutig die Jahreszeit, die die Leistung der hydro-geomorphologischer Arbeit nach Kahlschlägen prägte. 4) die Untersuchung von Grundwasserreaktionen auf das M8.8 Maule Erdbeben. Unter Grundwasserbedingungen kann der gesättigte Saprolith mit Verdichtung auf die Erdbebenerschütterungen reagieren. Dieser Prozess erhöht den hydraulischen Gradienten, der eine plausible Erklärung für den beobachteten Anstieg am Gebietsausfluss nach dem Erdbeben liefert. Die Verdichtung mobilisiert Grundwasser, das zudem von der ungesättigten Bodenmatrix aufgenommen werden kann. Hierdurch erhöht sich das Wasservolumen im Wurzelraum und begünstigt die Pflanzaktivität. Eine solche Aktivitätserhöhung spiegelt sich in verstärkten Tagesgängen wider. 5) die Untersuchung von hydrologischen Reaktionen auf das Erdbeben in der ungesättigten Zone. Hier zeigt sich, dass auch Bodenwasser aus der ungesättigten Bodenzone durch Erdbebenerschütterungen freigesetzt werden kann und den darunter liegenden Grundwasserspeicher zufließt. Hierdurch steigt der Grundwasserspiegel in den Talböden und erhöht dort die Pflanzenwasserverfügbarkeit. Durch inverse Modellierung wurde ein erdbebenbedingter Anstieg der Pflanzenaktivität von 30-60% quantifiziert. Beide Hypothesen sind jedoch auf Basis der verfügbaren Daten nicht eindeutig verifizierbar. Vergleicht man den Effekt des Erdbebens auf den Wasserhaushalt mit dem Effekt der exotischen Plantagenwälder zeigt sich, dass die Gesamtwirkung des Erdbebens auf den Wasserhaushalt vergleichsweise klein war und sich zudem auf kurze Zeiträume beschränkte.
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Karlsson, Daniel. "Logging impacts on catchment biogeochemistry: A review : with emphasis on northern boreal ecosystems." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-90175.
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The impacts of current forest management methods on surface water quality, especially in northern parts of Sweden, are largely unexplored. In this review reports linked to logging impacts on catchment biogeochemistry, (with special emphasis on boreal ecosystems) has been assessed. Logging disturbances in boreal forest catchments can change biogeochemical processes in soils by alter transpiration, soil conditions, temperature, soil microbial activities and water fluxes. Combined these changes can cause increased soil nutrient leaching to receiving waters. In the studies reviewed, dissolved organic carbon (DOC) concentrations and export generally increased after logging. Similar responses followed for phosphorous (P), but to a lesser extent for nitrogen (N). Streamflow and peakflow and the export of suspended matter (SM) can also be altered after logging. Removal of streamside vegetation may result in increased stream water temperatures and potentially affect lake water temperature, deepen the epilimnion and deplete oxygen (O2) concentrations. Increased wind exposure can resuspend sediments and potentially release bioavailable P. Affected lake water concentrations of N can be considered negligible after logging, whereas tot-P concentrations has shown to increase to an almost twofold level in some studies. The overall impact on the pelagic productivity are therefore most likely those connected to increased DOC and SM concentrations. The general impact on fish biomass can be considered insignificant. In conclusions, to improve future forest management and for further understanding concerning the biogeochemical environmental impacts that forestry might have on freshwaters, additional studies are still required.
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Branfireun, Brian A. "Catchment-scale hydrology and methylmercury biogeochemistry in the low boreal forest zone of the Precambrian Shield." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0022/NQ50321.pdf.
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Ward, David Jefford. "People, fire, forest and water in Wungong: the landscape ecology of a West Australian water catchment." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/2006.
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Bushfire is, in terms of human lives lost, property destroyed, and damage to natural systems, by far the most urgent environmental problem in Australia. This thesis tries to answer a number of questions about bushfire behaviour, history, effects, and management, in the Wungong Catchment of Western Australia. It does so by an overtly cross-disciplinary approach, involving a mixture of the three main streams of human knowledge, namely the humanities, natural science, and social science.First, I offer a literature review of several hundred books and papers drawn from the three main streams of knowledge mentioned above. The review includes some discussion of ‘bushfire epistemology’, a currently vague and neglected matter.The concept of ‘place’ is important to humans, so I then give a straightforward geographical description of Wungong Catchment, with some mention of the history of bushfire. To describe the vegetation, I use inductive statistics, and a method developed by me from the ideas of Delaunay (1929) and Dirichlet (1850). Given that there are hundreds of plant species within the catchment, I use a landscape approach, and only sketch the main tree species, and two iconic plants, the balga and the djiridji, both of which are important to the original custodians of the catchment, the Nyoongar people. There is discussion of other people’s research into the effect of bushfire on seed banks, and the flowering intervals of some plants of the jarrah forest.To see if Western Australia is anomalous, or fits into the worldwide pattern of humans using fire as a landscape management tool, I then examine some records of bushfire in other lands, including Africa, Madagascar, India, and Europe. The thesis then looks at the history of fire in the jarrah forest of Western Australia, based on observations by early European explorers and settlers from 1826 onward, the views of various foresters, and some opinions of current Nyoongar Elders.Using a mixture of natural science, applied mathematics, and archaeology, I give the results of cleaning the stems of those ancient plants called grasstrees, or balga (Xanthorrhoea spp.). These carry the marks of former bushfires, stretching back to 1750. They confirm historical reports of frequent fire in the jarrah forest, at 2-4 year intervals, and a recent decline in fire frequency. This contradicts the view, held by some, that European arrival increased the frequency of fire.As support for the balga findings, I present a simple mathematical model of self-organization in bushfire mosaics. It shows how lengthy bushfire exclusion can lead to disastrous situations, in which large areas of landscape become flammable and unstable. It shows how frequent, patchy burning can maintain a stable bushfire mosaic, with mild, beneficial fires. In the next chapter, I offer mathematical suggestions on how current unstable mosaics can be restabilized, by careful reintroduction of such burning.In dry, south-western Australia, water supply is an important topic, and a better understanding of the hydrological effects of bushfire may help with both bushfire and water management. I draw upon the natural science of forest hydrology, and the effects of fire in catchments. The evidence comes not only from Australia, but also from the United States, and South Africa.Turning to social science, I introduce Professor Peter Checkland’s ‘Soft Systems Methodology’, and suggest how it could be applied in resolving complicated conflict about bushfire management. I finish in legal style, with a summing up, and a verdict on the use of bushfire as a land management tool in Wungong Catchment, and possibly in other flammable landscapes.
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Borgert, Jasmin. "Spruce Forests and Peat Wetlands in Lake Bolmen’s Catchment Both Leak and Degrade Coloured Dissolved Organic Carbon." Thesis, Högskolan i Halmstad, Akademin för företagande, innovation och hållbarhet, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-45323.
Full textAbstract:
Lake browning in the northern hemisphere is endangering crucial ecosystem services. Darker water decreases fish and primary production as well as touristic and recreational values. It furthermore requires intensive treatment to receive safe drinking water. Brownification is connected to iron and coloured dissolved organic carbon (DOC). In Sweden, spruce plantations leak DOC, possibly depending in their DOC rate on tree age. Whereas wetlands are known to purify water and might contribute to the degradation of DOC. This thesis aims to investigate how different land use types and other parameters affect water colour. Ditches flowing through old spruce forests, young spruce forests, and peat wetlands in the Lake Bolmen catchment, southwestern Sweden, were sampled at in- and outlet. Highly significantly positive relationships between DOC, iron and absorbance were found. The relationship was strongest between DOC and absorbance (R² = 0.88; p < 0.001) and weakest between DOC and iron (R² = 0.54; p < 0.001). High variability led to no significant differences in the release of DOC and iron between the three land use types. However, older forests tended to increase DOC and iron loading compared to younger forests. This study suggests that not only spruce forests in general are affecting the brownification, but that several different factors like age and underlying soil type might play a critical role.
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Bidin, Kawi. "Spatio-temporal variability in rainfall and wet-canopy evaporation within a small catchment recovering from selective tropical forestry." Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369023.
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Gottselig, Nina Verfasser], Erwin [Akademischer Betreuer] Klumpp, and Andreas [Akademischer Betreuer] [Schäffer. "The role of natural nanoparticles and colloids for phosphorus binding in forested headwater catchments / Nina Gottselig ; Erwin Klumpp, Andreas Schäffer." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1125973587/34.
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Payeur-Poirier, Jean-Lionel [Verfasser], and Stefan [Akademischer Betreuer] Peiffer. "Hydrological dynamics of forested catchments as influenced by the East Asian summer monsoon / Jean-Lionel Payeur-Poirier ; Betreuer: Stefan Peiffer." Bayreuth : Universität Bayreuth, 2018. http://d-nb.info/1156326508/34.
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Gottselig, Nina [Verfasser], Erwin Akademischer Betreuer] Klumpp, and Andreas [Akademischer Betreuer] [Schäffer. "The role of natural nanoparticles and colloids for phosphorus binding in forested headwater catchments / Nina Gottselig ; Erwin Klumpp, Andreas Schäffer." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1125973587/34.
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Elsenbeer, Helmut, Daniel Lorieri, and Mike Bonell. "Mixing model approaches to estimate storm flow sources in an overland flow-dominated tropical rain forest catchment." Universität Potsdam, 1995. http://opus.kobv.de/ubp/volltexte/2008/1694/.
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Previous hydrometric studies demonstrated the prevalence of overland flow as a hydrological pathway in the tropical rain forest catchment of South Creek, northeast Queensland. The purpose of this study was to consider this information in a mixing analysis with the aim of identifying sources of, and of estimating their contribution to, storm flow during two events in February 1993. K and acid-neutralizing capacity (ANC) were used as tracers because they provided the best separation of the potential sources, saturation overland flow, soil water from depths of 0.3, 0.6, and 1.2 m, and hillslope groundwater in a two-dimensional mixing plot. It was necessary to distinguish between saturation overland flow, generated at the soil surface and following unchanneled pathways, and overland flow in incised pathways. This latter type of overland flow was a mixture of saturation overland flow (event water) with high concentrations of K and a low ANC, soil water (preevent water) with low concentrations of K and a low ANC, and groundwater (preevent water) with low concentrations of K and a high ANC. The same sources explained the streamwater chemistry during the two events with strongly differing rainfall and antecedent moisture conditions. The contribution of saturation overland flow dominated the storm flow during the first, high-intensity, 178-mm event, while the contribution of soil water reached 50% during peak flow of the second, low-intensity, 44-mm event 5 days later. This latter result is remarkably similar to soil water contributions to storm flow in mountainous forested catchments of the southeastern United States. In terms of event and preevent water the storm flow hydrograph of the high-intensity event is dominated by event water and that of the low-intensity event by preevent water. This study highlights the problems of applying mixing analyses to overland flow-dominated catchments and soil environments with a poorly developed vertical chemical zonation and emphasizes the need for independent hydrometric information for a complete characterization of watershed hydrology and chemistry.
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Humphries, Stefan. "Stable Isotopes of Sulphur and Oxygen in Forested Catchments: Insight from New Techniques into Sulphur Cycling and Dissolved Organic Matter Alteration." Thesis, University of Waterloo, 2003. http://hdl.handle.net/10012/1270.
Full textAbstract:
Dissolved organic matter (DOM) is present in all forested catchments and can be important in binding metals, absorbing UV, and the transport of nutrients (C, N, S, P). DOM is extremely heterogeneous in time and space, making it difficult to characterize. New techniques have been developed to determine δ34S and δ18O in DOM. These techniques have been applied to samples from Harp and Plastic Lake catchments (45º23'N, 79º 08'W, 45º11'N, 78º 50'W) in order to obtain information about sources and sinks of DOM within forested catchments on the Canadian Shield. In conjunction with sulphate and DOC concentrations, this new data provides valuable insight into sulphur cycling and DOM alteration within these catchments. Data generated for δ34S-DOM and δ18O-DOM appears to be the first data reported in the literature for DOM.
The inorganic (δ34S-SO42-) and organic S (δ34S-DOM) differs by environment in both catchments. The range of δ34S-SO42- is between 3. 3‰ and 10. 3‰, and the range of δ34S-DOM is from 3. 4‰ to 8. 7‰. Sulphate in the Harp Lake catchment in most samples is subject to some sort of cycling within the watershed, since δ34S-SO42- differs from precipitation. In the Harp Lake catchment, upland δ34S-SO42- is influenced by historical precipitation. The δ34S-DOM is derived from leaching and microbial activity of DOM from organic horizons in the soil. The δ34S-SO42- and δ34S-DOM of wetland streams is extremely variable, controlled by hydrology. The δ34S-SO42- provides information on oxidation-reduction dynamics in the wetland, and δ34S-DOM provides information about sources of DOS in the wetland. The δ34S-SO42- and δ34S-DOM are possibly related in Harp Lake. Mineralization of DOS as evidenced by δ34S-DOM and DOS concentrations could be a small input of SO42- into Harp Lake.
It is possible δ18O-DOM could be an indicator of DOM alteration. The range of δ18O-DOM is between 8. 2‰ and 14. 4‰. The δ18O-DOM in the Harp Lake catchment is highly correlated with relative molecular weight, which has been shown to decrease with increasing alteration. Wetland streams show the largest range in δ18O-DOM, while uplands, groundwater, and Harp Lake are the least varied. The highest δ18O-DOM values are from sources of DOM such as leaf leachates (representative of forest floor litter) and wetlands. The most depleted samples are from groundwater and Harp Lake which typically contain highly altered DOM.
The δ34S-DOM and δ18O-DOM can provide valuable information on sources of DOM and DOM alteration within the catchment. The δ18O-DOM could also allow the separation of autochthonous and allochthonous DOM in lakes.
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Norström, Sara H. "Soil and stream water chemistry in a boreal catchment - interactions, influences of dissolved organic matter and effects of wood ash application." Doctoral thesis, Mittuniversitetet, Institutionen för naturvetenskap, teknik och matematik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-12998.
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Two small bordering catchments in Bispgården, Central Sweden, wereinvestigated in regard to soil solution and stream water chemistry during the frostfree seasons of 2003-2007. Both catchments were drained by first order streams,Fanbergsbäcken and Gråbergsbäcken, and in Fanbergsbäckens catchment anextensive investigation of the soil and soil solution chemistry was conducted bylysimeter and centrifugation sampling. The area of intensive soil solutioninvestigation was situated in a slope towards a stream incorporating a rechargearea, with podzolic soil, and a discharge area close to the stream with an arenosolsoil. Samples were continuously taken in both the recharge- and the discharge areaof the slope, and stream water was sampled in the streams of both catchments. Themain variables of interest of the study were the interactions, the influence ofdissolved organic carbon and the effects of wood ash application to soil solutionand stream water.The natural variations and the interactions between soil solution and streamwater were monitored during 2003-2004. In soil solution, most of the investigatedsubstances tended to increase during the growing season, due to weathering andmicrobial degradation of biota. Ca, Mg, Al and Fe were highly associated todissolved organic carbon (DOC) throughout the catchment. The low molecularfraction of DOC seemed to have a higher impact on the soil processes in therecharge area, while high molecular DOC was more important for transport ofcations in the discharge area and the stream water.The concentration of different substances in the two streams differedsignificantly, even though the catchments were similar in size, shape andforestation. The seasonal patterns of most of the substances measured weresignificantly correlated between the streams, however. Cations and pH correlatedwell with DOC and flow. The flow pattern driven by precipitation seems to be thedriver of the stream water chemistry.Wood ash was applied at a dosage of 3 ton/ha to one of the catchments in theautumn of 2004, to investigate the initial effects on the soil solution- and streamwater chemistry. WAA is recommended by the Swedish Forest Agency tocounteract acidification in soil and runoff that may be caused by an intensivebiomass harvesting. The impact of the WAA was studied during 2005-2006.Compared to the control temporarily higher concentrations of K, Ca and SO4 wereobserved in the soil solution of the ashed area. In the stream water the effects of theWAA were easier to distinguish due to higher sampling frequency. The strongesteffect was seen for K, but increases in the stream water were also noted for DOC,Ca, Mg, Si, Cl and malonate. No increase in pH could be statistically verifiedhowever, and overall the initial effects of the WAA seem mild.Två angränsande avrinningsområden i Bispgården i centrala Sverigeundersöktes under den snöfria säsongen 2003-2006. Båda avrinningsområdenadränerades av första ordningens bäckar och i det ena, Fanbergsbäckensavrinningsområde, gjordes en omfattande undersökning av mark och markvattenkemin.Markvatten provtogs genom centrifugering och med lysimetrar.Provtagningen gjordes i inströmningsområdet där jordmånen var en typiskpodzol samt närmare bäcken, i utströmningsområdet, där jordmånen var enarenosol. Bäckvatten provtogs i båda avrinningsområdena. Interaktioner mellanmark, markvatten och bäckvatten undersöktes med särskilt fokus på inverkan avorganiskt kol samt påverkan av askåterföring.De naturliga variationerna i markkemin samt interaktionerna mellan mark- ochbäck vatten undersöktes 2003-2004. I markvatten ökade merparten av de studeradeämnena under provtagningssäsongen beroende av ökad vittring och recirkulationav biota och fallförna. Ca, Al och Fe var i stor utsträckning associerade till löstorganiskt kol (DOC). Den lågmolekylära fraktionen av DOC hade en störreinverkan på markprocesserna i inströmningsområdet, medan den högmolekyläradelen var viktigare för transport av katjoner i utströmningsområdet samt ibäckvattnet.Koncentrationsnivåerna av olika substanser i bäckarna uppvisade skillnadertrots avrinningsområdenas yttre likheter med avseende på storlek, form ochbeskogning. Trots de kvantitativa skillnaderna erhölls emellertid liknandesäsongsvariationer i koncentrationerna, vilket indikerade att kemin i huvudsakstyrdes av mängden DOC som i sin tur berodde av avrinningen som drevs avnederbörden. Höga halter av Ca, Mg, Al och Fe återfanns associerade tillhögmolekylärt DOC i bäckvattnet i en utsträckning som inte rapporterats tidigare.På hösten 2004 spreds 3 ton aska/ha till Fanbergsbäckens avrinningsområde föratt undersöka de initiala effekterna på mark- och bäckvatten kemin. Askåterföringbör ske minst en gång per omloppstid vid helträdsavverkning, i enlighet medSkogsstyrelsens rekommendationer, främst för att motverka försurning i mark ochavrinnande vatten som antas uppstå vid intensivt uttag av biomassa. De initialaeffekterna av askåterföringen på mark- och bäckvattnets kemi studerades under2005-2006 och Gråbergsbäcken kunde användas som obehandlad kontroll vidundersökning av vattenkemin i Fanbergsbäcken. I undersökningen av markvattenviåterfanns stora säsongsvariationer, vilket gjorde det svårt att urskilja eventuellaeffekter av askåterföringen. Tillfälligt högre värden av K, Ca och SO4 återfannsdock i det askade området i jämförelse med kontrollområdet. På grund av högreprovtagningsfrekvens i bäckvattnet var det lättare att påvisa förändringar ibäckvatten kemin. Framförallt märktes en signifikant ökning av K jämfört medkontrollbäcken. Sådana ökningar, om än inte lika markanta återfanns också förDOC, Ca, Mg, Si, Cl och malonat. En tendens till ökat pH kunde observeras, mendenna kunde inte verifieras statistiskt. De initiala effekterna av askåterföringen varsåledes till synes milda, och den eftertraktade pH-effekten erhölls ej i dennaundersökning.
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dos, Santos Toledo Busarello Mariana. "Machine Learning Applied to Reach Classification in a Northern Sweden Catchment." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-184140.
Full textAbstract:
An accurate fine resolution classification of river systems positively impacts the process of assessment and monitoring of water courses, as stressed by the European Commission’s Water Framework Directive. Being able to attribute classes using remotely obtained data can be advantageous to perform extensive classification of reaches without the use of field work, with some methods also allowing to identify which features best described each of the process domains. In this work, the data from two Swedish sub-catchments above the highest coastline was used to train a Random Forest Classifier, a Machine Learning algorithm. The obtained model provided predictions of classifications and analyses of the most important features. Each study area was studied separately, then combined. In the combined case, the analysis was made with and without lakes in the data, to verify how it would affect the predictions. The results showed that the accuracy of the estimator was reliable, however, due to data complexity and imbalance, rapids were harder to be classify accurately, with an overprediction of the slow-flowing class. Combining the datasets and having the presence of lakes lessened the shortcomings of the data imbalance. Using the feature importance and permutation importance methods, the three most important features identified were the channel slope, the median of the roughness in the 100-m buffer, and the standard deviation of the planform curvature in the 100-m buffer. This finding was supported by previous studies, but other variables expected to have a high participation such as lithology and valley confinement were not relevant, which most likely relates to the coarseness of the available data. The most frequent errors were also placed in maps, showing there was some overlap of error hotspots and areas previously restored in 2010.