Unit Response Approach for Priority Determination of Flood Source Areas

Saghafian, Bahram; Khosroshahi, Mohammad

doi:10.1061/(asce)1084-0699(2005)10:4(270)

Cited by 36 publications

(30 citation statements)

References 3 publications

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“…Lane (2003) concluded that timing was a secondary critical factor to consider, and this thesis has confirmed and even corroborated the importance of this result. These downscaling approaches highlighted the importance of upstream sub-catchments in explaining catchment scale flooding which is the same as previous studies which found that the proximal subcatchments to the outlet were the least important (Saghafian and Khosroshahi, 2005;Roughani et al, 2007). This strengthens the possibility of using upstream rural land management as a possible option in mitigating downstream flood risk.…”

Section: Discussionsupporting

confidence: 82%

“…However, Saghafian and Khosroshahi (2005) found that the ranking of sub-catchments by area and importance in effecting flooding may not be the same. This was thought to be caused by factors such as channel routing and the timing and synchronicity of flows.…”

Section: Figure 611 Contribution Of Each Sub-catchment In Terms Of Pmentioning

confidence: 95%

“…This highlights the issue of proximity of each subcatchment to the catchment outlet. Saghafian and Khosroshahi (2005) found that the effect of the most proximal sub-catchments to the outlet were the lowest. This was because the flows from these tributaries reached the catchment outlet before the contributions from the other tributaries arrived.…”

Section: Pc1mentioning

confidence: 96%

“…Saghafian and Khosroshahi (2005) found that for higher return period flood events the spatially distributed response of the catchment and channel routing processes become less important and the whole catchment responds in a more homogeneous manner. However, this study has found that changes to individual sub-catchments can still have a significant effect on downstream flood magnitudes, even for extreme events.…”

Section: Summary Of Spatial Downscalingmentioning

confidence: 98%

“…Therefore this thesis aims to develop approaches whereby the optimum areas to focus limited resources can be discovered. Saghafian and Khosroshahi (2005) identified flood source areas through a combined hydrological-hydraulic modelling approach, whereby tributary inputs were sequentially turned off and the impact downstream assessed through hydrograph change. Roughani et al, (2007) prioritised sub-catchments through changing the contribution of each tributary, also using a modelling approach.…”

Section: ) To Determine Which Areas (Sub-catchments) Of the Catchmenmentioning

confidence: 99%

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Rural land management impacts on catchment scale flood risk

Pattison¹

2010

Role of Hydrology in Managing Consequences of a Changing Global Environment

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source• a link is made to the metadata record in Durham E-Theses• the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full Durham E-Theses policy for further details. Most approaches to this problem aim to upscale from individual grid cells to whole catchments, something that restricts the complexity of possible process representation, produces models that may not be parsimonious with the data needed to calibrate them and, faced with data uncertainties, provides computational limitations on the extent to which model uncertainty can be fully explored. Rather than upscaling to problems of concern, this thesis seeks to downscale from locations of known flood risk, as a means of identifying where land use management changes might be beneficial and then uses numerical modelling to identify the kinds of management changes required in those downscaled locations. Thus, the aim of this thesis is to test an approach to understanding the impacts of rural land management upon flood risk based upon catchment-to-source downscaling.This thesis uses the case study of the River Eden catchment (2400 km 2 ) as a test (1) it was shown to have a significant impact on downstream flood risk; and (2) it had range of data and information needed for modelling land use changes.The second part of this thesis explored the land management scenarios that could be used to reduce flood risk at the catchment scale. The scenarios to be tested were determined through a stakeholder participation approach, whereby workshops were held to brainstorm and prioritise land management options, and then to identify specific locations within the Eamont sub-catchment where they could tested. There were two main types of land management scenarios chosen: (1) landscape-scale changes, including afforestation and compaction; and (2) corresponding to a 5.8% decrease in peak discharge. A key conclusion is that land management practices have been shown to have an effect on catchment scale flooding, even for extreme flood events. However, the effect of land management scenarios are both spatially and temporally dependent i.e. the same land management practice has different effects depending on where it is implemented, and when implemented in the same location has different effects on different flood events.

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Section: Discussionsupporting

confidence: 82%

Section: Figure 611 Contribution Of Each Sub-catchment In Terms Of Pmentioning

confidence: 95%

Section: Pc1mentioning

confidence: 96%

Section: Summary Of Spatial Downscalingmentioning

confidence: 98%

Section: ) To Determine Which Areas (Sub-catchments) Of the Catchmenmentioning

confidence: 99%

See 3 more Smart Citations

Rural land management impacts on catchment scale flood risk

Pattison¹

2010

Role of Hydrology in Managing Consequences of a Changing Global Environment

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Fragmentation and thresholds in hydrological flow‐based ecosystem services

Thomas

Masante

Jackson

et al. 2020

Ecological Applications

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Loss and fragmentation of natural land cover due to expansion of agricultural areas is a global issue. These changes alter the configuration and composition of the landscape, particularly affecting those ecosystem services (benefits people receive from ecosystems) that depend on interactions between landscape components. Hydrological mitigation describes the bundle of ecosystem services provided by landscape features such as woodland that interrupt the flow of runoff to rivers. These services include sediment retention, nutrient retention and mitigation of overland water flow. The position of woodland in the landscape and the landscape topography are both important for hydrological mitigation. Therefore, it is crucial to consider landscape configuration and flow pathways in a spatially explicit manner when examining the impacts of fragmentation. Here we test the effects of landscape configuration using a large number (>7,000) of virtual landscape configurations. We created virtual landscapes of woodland patches within grassland, superimposed onto real topography and stream networks. Woodland patches were generated with user‐defined combinations of patch number and total woodland area, placed randomly in the landscape. The Ecosystem Service model used hydrological routing to map the “mitigated area” upslope of each woodland patch. We found that more fragmented woodland mitigated a greater proportion of the catchment. Larger woodland area also increased mitigation, however, this increase was nonlinear, with a threshold at 50% coverage, above which there was a decline in service provision. This nonlinearity suggests that the benefit of any additional woodland depends on two factors: the level of fragmentation and the existing area of woodland. Edge density (total edge of patches divided by area of catchment) was the best single metric in predicting mitigated area. Distance from woodland to stream was not a significant predictor of mitigation, suggesting that agri‐environment schemes planting riparian woodland should consider additional controls such as the amount of fragmentation in the landscape. These findings highlight the potential benefits of fragmentation to hydrological mitigation services. However, benefits for hydrological services must be balanced against any negative effects of fragmentation or habitat loss on biodiversity and other services.

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Application of the WEPP model to determine sources of run-off and sediment in a forested watershed

2014

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This study investigates critical run‐off and sediment production sources in a forested Kasilian watershed located in northern Iran. The Water Erosion Prediction Project (WEPP) watershed model was set up to simulate the run‐off and sediment yields. WEPP was calibrated and validated against measured rainfall–run‐off–sediment data. Results showed that simulated run‐off and sediment yields of the watershed were in agreement with the measured data for the calibration and validation periods. While low and medium values of run‐off and sediment yields were adequately simulated by the WEPP model, high run‐off and sediment yield values were underestimated. Performance of the model was evaluated as very good and satisfactory during the calibration and validation stages, respectively. Total soil erosion and sediment load of the study watershed during the study period were determined to be 10 108 t yr−1 and 8735 t yr−1, respectively. The northern areas of the watershed with dry farming were identified as the critical erosion prone zones. To prioritize the subwatersheds based on their contribution to the run‐off and sediment production at the watershed's main outlet, unit response approach (URA) was applied. In this regard, subwatersheds close to the main outlet were found to have the highest contribution to sediment yield of the whole watershed. Results indicated that depending on the objective of land and water conservation practices, particularly, for controlling sediment yield at the main outlet, critical areas for implementing the best management practices may be identified through conjunctive application of WEPP and URA. Copyright © 2014 John Wiley & Sons, Ltd.

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Unit Response Approach for Priority Determination of Flood Source Areas

Cited by 36 publications

References 3 publications

Rural land management impacts on catchment scale flood risk

Rural land management impacts on catchment scale flood risk

Fragmentation and thresholds in hydrological flow‐based ecosystem services

Application of the WEPP model to determine sources of run-off and sediment in a forested watershed

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