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Stuart N Lane - One of the best experts on this subject based on the ideXlab platform.
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the effects of river restoration on Catchment Scale flood risk and flood hydrology
Earth Surface Processes and Landforms, 2016Co-Authors: Simon Dixon, D A Sear, Nicholas A Odoni, Tim Sykes, Stuart N LaneAbstract:A rising exposure to flood risk is a predicted consequence of increased development in vulnerable areas and an increase in the frequency of extreme weather events due to climate change. In the face of this challenge, a continued reliance on engineered at-a-point flood defences is seen as both unrealistic and undesirable. The contribution of ‘soft engineering’ solutions (e.g. riparian forests, wood in rivers) to integrated, Catchment Scale flood risk management has been demonstrated at small Scales but not larger ones. In this study we use reduced complexity hydrological modelling to analyse the effects of land use and channel changes resulting from river restoration upon flood flows at the Catchment Scale. Results show short sections of river-floodplain restoration using engineered logjams, typical of many current restoration schemes, have highly variable impacts on Catchment-Scale flood peak magnitude and so need to be used with caution as a flood management solution. Forested floodplains have a more general impact upon flood hydrology, with areas in the middle and upper Catchment tending to show reductions in peak magnitude at the Catchment outflow. The most promising restoration scenarios for flood risk management are for riparian forest restoration at the sub-Catchment Scale, representing 20–40% of the total Catchment area, where reductions in peak magnitude of up to 19% are observed through de-synchronization of the timings of sub-Catchment flood waves. Sub-Catchment floodplain forest restoration over 10–15% of total Catchment area can lead to reductions in peak magnitude of 6% at 25 years post-restoration. Copyright © 2016 John Wiley & Sons, Ltd.
Joris De Vente - One of the best experts on this subject based on the ideXlab platform.
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factors controlling sediment yield at the Catchment Scale in nw mediterranean geoecosystems
Journal of Soils and Sediments, 2011Co-Authors: Joris De Vente, Rubia Verduyn, Gert Verstraeten, Matthias Vanmaercke, Jean PoesenAbstract:Purpose This study aimed to (1) increase understanding of the relation between sediment yield and environmental variables at the Catchment Scale; (2) test and validate existing and newly developed regression equations for prediction of sediment yield; and (3) identify how better predictions may be obtained.
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soil carbon erosion and stock as affected by land use changes at the Catchment Scale in mediterranean ecosystems
Agriculture Ecosystems & Environment, 2009Co-Authors: Carolina Boixfayos, Joris De Vente, J Albaladejo, M MartinezmenaAbstract:Abstract Catchments behave as sources or sinks of soil carbon, depending on the magnitude and type of land use changes within their drainage area, on the intensity of erosion processes and on the fate of eroded sediments. The effect of changing land uses on the organic soil carbon (C) stock and the soil C transported by water erosion and buried in depositional wedges behind check-dams was estimated in a Mediterranean Catchment in SE Spain. Changes in land use patterns in the Catchment between 1956 and 1997 (57% decrease in areas dedicated to agriculture and 1.5-fold increase of the total forest cover) induced an accumulation rate of total organic carbon (TOC) in the soil of 10.73 g m −2 year −1 . Mineral-associated organic carbon (MOC) was the main soil carbon pool (70%). Particulate organic carbon (POC) was highest in the shrubland soils (33%). The average sediments/soil enrichment ratio at the subCatchment Scale (8–125 ha) was 0.59 ± 0.43 g kg −1 . Eroded soil C accounted for between 2% and 78% of the soil C stock in the first 5 cm of the soil in the subCatchments. The C erosion rate varied between 0.008 and 0.2 t ha −1 year −1 . Observed changes in land use (decrease in agricultural areas) reduced soil C erosion, although sediments from non-agricultural sources are richer in organic C. At Catchment Scale from the 4% of the soil C stock mobilized by water erosion, 77% is buried in the sediment wedges behind check-dams. Soil C replacement due to increased vegetation cover between 1974 and 1997 represented a 36% of the original soil organic C stock. All together represent an erosion-induced sink of soil organic C of 40% compared to the original levels of 23 years before. This has caused the Catchment to behave as a soil C sink within the soil erosion subsystem since the 1950s. The meaning of this erosion-induced C sink in a wider C balance which takes into account soil respiration remains uncertain.
A J Jakeman - One of the best experts on this subject based on the ideXlab platform.
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a review of Catchment Scale water quality and erosion models and a synthesis of future prospects
Environmental Modelling and Software, 2019Co-Authors: Wendy Merritt, Barry Croke, Tony Weber, A J JakemanAbstract:Abstract Catchment-Scale water quality models have become important tools for water quality management, planning and reporting worldwide. In this review, we synthesise recent developments in water quality modelling, focusing on Catchment-Scale models of freshwater, non-urban systems and their ability to support Catchment management. We explore 10 key attributes in selected existing water quality models. These attributes can be characterised as: model use (model purposes, representation of constituents, scenario analysis, and documentation), model development (process representation, spatial heterogeneities, temporal dynamics, and data requirements), and model performance (calibration, validation and uncertainty tools). We deliberate on 11 key challenges and/or emerging topics in Catchment water quality modelling: large-Scale applications, model integration, model usability and communication, preliminary data analysis, modelling management practices, technology advancement, incorporating soft data, model identifiability, uncertainty analysis, good modelling practices and capacity building, and differentiating the effects of climate impacts from those associated with land use and management practices.
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a framework for integrated hydrologic sediment and nutrient export modelling for Catchment Scale management
Environmental Modelling and Software, 2004Co-Authors: Lachlan Newham, Rebecca Letcher, A J Jakeman, T KobayashiAbstract:Abstract Many Catchments in Australia have experienced increased sediment and nutrient loadings and concomitant declines in water quality and increases in problematic blue–green algal blooms over the past several decades. This paper describes an integrated hydrologic, sediment and nutrient export modelling framework known as Catchment-Scale management of diffuse sources (CatchMODS). The modelling framework is designed to simulate and assess Catchment-Scale land and water management activities designed to reduce nutrient and sediment delivery to receiving waters. The Ben Chifley Dam Catchment in New South Wales, Australia is used as a case study for describing the development of the framework. Improving water quality through reduction of sediment and nutrient loads will reduce the probability of algal bloom occurrence in the dam. The innovation of the system is the integration of otherwise separate modelling approaches to enable biophysical and economic assessment of different management options. The outputs from the research are used to improve and focus on-ground remediation, targeted to specific stream reaches or subCatchment areas, as well as to encourage sustainable management practices more broadly in the Catchment. With minimal modification, the methods developed are applicable elsewhere to address water quality decline.
Gebreyesus Brhane Tesfahunegn - One of the best experts on this subject based on the ideXlab platform.
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Catchment Scale spatial variability of soil properties and implications on site specific soil management in northern ethiopia
Soil & Tillage Research, 2011Co-Authors: Gebreyesus Brhane Tesfahunegn, Lulseged Tamene, Paul L. G. VlekAbstract:Abstract Scientific information on the spatial variability and distribution of soil properties is critical for understanding ecosystem processes and designing sustainable soil–crop and environmental management decisions. However, little is known on spatial distribution and variability of soil properties at Catchment-Scale in many tropical developing regions including Ethiopia. This study aims to examine Catchment-Scale spatial dependence and variability of soil properties using classical and geostatistical methods to indicate for site-specific soil management in the Mai-Negus Catchment, northern Ethiopia. Soil samples were collected based on sampling zones identified by the knowledge of local farmers and field observation and analyzed following standard laboratory procedures for selected soil properties. The coefficient of variation of the soil properties ranged from 8.6% (pH) to 73.4% (clay) at Catchment-Scale. The mean soil organic carbon (OC) (1.21%), total nitrogen (TN) (0.12%), and available phosphorus (Pav) (7.8 mg kg −1 ) of the soils in the Catchment were low, whereas high in exchangeable potassium (Ex K) (0.77 cmol c kg −1 ), and medium in cation exchange capacity (CEC) (23.4 cmol c kg −1 ) compared to the rate for African soils reported in literature. The results of semivariograms indicated a strong (8%) to moderate (63%) degree of spatial dependence for the soil properties. In addition, the goodness-of-prediction criterium ( G ) are higher than zero indicating that spatial soil properties mapped based on kriging interpolation are more accurate than the Catchment average value (classical statistics) for site-specific management decisions. This study indicates a wide range of variability in the soil properties as the kriged maps of the soil properties at Catchment-Scale showed for sand (15–70%), silt (18–77%), clay (3–51%), bulk density (1.00–2.00 Mg m −3 ), OC (0.20–4.5%), TN (0.05–1.0%), Pav (1–26 mg kg −1 ), Ex K (0.10–1.30 cmol c kg −1 ), exchangeable calcium, Ex Ca (5–28 cmol c kg −1 ), exchangeable magnesium, Ex Mg (2–15 cmol c kg −1 ), CEC (8–51 cmol c kg −1 ), and iron (3–45 mg kg −1 ). The lowest soil nutrients and fine soil particles were measured on the sub-sampling zones such as low soil quality, eroded sites, and marginal land soils. Introducing appropriate interventions such as conservation tillage, fertilizer rates, agro-forestry practices, crop rotation, exclosure degraded lands, and conservation measures based on the kriged soil properties maps produced is crucial for sustainable production and environmental services.
Renato Morbidelli - One of the best experts on this subject based on the ideXlab platform.
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Catchment Scale soil moisture spatial temporal variability
Journal of Hydrology, 2012Co-Authors: Luca Brocca, T Tullo, Florisa Melone, Tommaso Moramarco, Renato MorbidelliAbstract:Summary The characterization of the spatial–temporal variability of soil moisture is of paramount importance in many scientific fields and operational applications. However, due to the high variability of soil moisture, its monitoring over large areas and for extended periods through in situ point measurements is not straightforward. Usually, in the scientific literature, soil moisture variability has been investigated over short periods and in large areas or over long periods but in small areas. In this study, an effort to understanding soil moisture variability at Catchment Scale (>100 km 2 ), which is the size needed for some hydrological applications and for remote sensing validation analysis, is done. Specifically, measurements were carried out in two adjacent areas located in central Italy with extension of 178 and 242 km 2 and over a period of 1 year (35 sampling days) with almost weekly frequency except for the summer period because of soil hardness. For each area, 46 sites were monitored and, for each site, 3 measurements were performed to obtain reliable soil moisture estimates. Soil moisture was measured with a portable Time Domain Reflectometer for a layer depth of 0–15 cm. A statistical and temporal stability analysis is employed to assess the space–time variability of soil moisture at local and Catchment Scale. Moreover, by comparing the results with those obtained in previous studies conducted in the same study area, a synthesis of soil moisture variability for a range of spatial Scales, from few square meters to several square kilometers, is attempted. For the investigated area, the two main findings inferred are: (1) the spatial variability of soil moisture increases with the area up to ∼10 km 2 and then remains quite constant with an average coefficient of variation equal to ∼0.20; (2) regardless of the areal extension, the soil moisture exhibits temporal stability features and, hence, few measurements can be used to infer areal mean values with a good accuracy (determination coefficient higher than 0.88). These insights based on in situ soil moisture observations corroborate the opportunity to use point information for the validation of coarse resolution satellite images. Moreover, the feasibility to use coarse resolution data for hydrological applications in small to medium sized Catchments is confirmed.