scholarly journals Sedimentological and geomorphological effects of the 1997 and 1998 flood sequence on the Lower Snowy River, Victoria

2016 ◽  
Vol 128 (2) ◽  
pp. 25 ◽  
Author(s):  
Wayne D. Erskine ◽  
Lisa M. Turner ◽  
Teresa A. Rose
Keyword(s):  
Grain Size ◽  
Channel Morphology ◽  
Peak Discharge ◽  
Maximum Depth ◽  
Peak Ratio ◽  
Flood Peak ◽  
Depth Ratio ◽  
Channel Boundary ◽  
Bed Material ◽  
The Impact

Three floods with flood peak ratios (peak discharge/mean annual flood) ranging between 0.65 and 5.35 occurred on the lower Snowy River in Victoria between June 1997 and August 1998. The June 1998 flood was the largest event downstream of the Rodger River junction where the flood peak ratio was >4. Pre- and post-flood investigations were carried out at the three Snowy River benchmarking sites in Victoria (McKillops Bridge, Sandy Point and Bete Bolong) to determine the impact of the floods on channel-boundary sediments and morphology. Few significant changes in graphic grain-size statistics for channel-boundary sediments were found at McKillops Bridge and Sandy Point. At Bete Bolong, there were many significant changes in the grain-size statistics of both the bed material and bank sediment. The variance and mean of a number of benchfull and bankfull channel morphologic parameters (width, area, mean depth, maximum depth, width‒maximum depth ratio) did not change significantly at McKillops Bridge and Sandy Point. At Bete Bolong, benchfull mean depth and area increased significantly due to bed degradation. Floods with a flood peak ratio of at least 4 are important for mobilising channel-boundary sediments and hence modifying channel morphology on the lower Snowy River.

scholarly journals Benefits and limitations of data assimilation for discharge forecasting using an event-based rainfall–runoff model

2013 ◽  
Vol 13 (3) ◽  
pp. 583-596 ◽  
Author(s):  
M. Coustau ◽  
S. Ricci ◽  
V. Borrell-Estupina ◽  
C. Bouvier ◽  
O. Thual
Keyword(s):  
Data Assimilation ◽  
Hydrological Model ◽  
Peak Discharge ◽  
State Variables ◽  
Rainfall Runoff ◽  
Discharge Data ◽  
Southern France ◽  
Flood Peak ◽  
Event Based ◽  
The Impact

Abstract. Mediterranean catchments in southern France are threatened by potentially devastating fast floods which are difficult to anticipate. In order to improve the skill of rainfall-runoff models in predicting such flash floods, hydrologists use data assimilation techniques to provide real-time updates of the model using observational data. This approach seeks to reduce the uncertainties present in different components of the hydrological model (forcing, parameters or state variables) in order to minimize the error in simulated discharges. This article presents a data assimilation procedure, the best linear unbiased estimator (BLUE), used with the goal of improving the peak discharge predictions generated by an event-based hydrological model Soil Conservation Service lag and route (SCS-LR). For a given prediction date, selected model inputs are corrected by assimilating discharge data observed at the basin outlet. This study is conducted on the Lez Mediterranean basin in southern France. The key objectives of this article are (i) to select the parameter(s) which allow for the most efficient and reliable correction of the simulated discharges, (ii) to demonstrate the impact of the correction of the initial condition upon simulated discharges, and (iii) to identify and understand conditions in which this technique fails to improve the forecast skill. The correction of the initial moisture deficit of the soil reservoir proves to be the most efficient control parameter for adjusting the peak discharge. Using data assimilation, this correction leads to an average of 12% improvement in the flood peak magnitude forecast in 75% of cases. The investigation of the other 25% of cases points out a number of precautions for the appropriate use of this data assimilation procedure.

Effects of channel engineering on flood dynamics along the middle and lower Rhône over the last two centuries.

2021 ◽  
Author(s):  
Mathieu Lucas ◽  
Michel Lang ◽  
Jérôme Le Coz ◽  
Benjamin Renard ◽  
Hervé Piegay
Keyword(s):  
Peak Discharge ◽  
Anthropogenic Pressures ◽  
Flood Peak ◽  
Area Of Interest ◽  
Channel Engineering ◽  
Indirect Consequence ◽  
Channel Patterns ◽  
Flood Dynamics ◽  
The Impact ◽  
Flood Waves

<p>The Rhône River has undergone many anthropogenic transformations to improve his navigability and produce hydroelectricity since the mid-19th century. From the longitudinal dikes of the 1850’s to the hydroelectric diversion schemes of the 1950’s and 1960’s, these structures had a direct impact on the channel geometry along the 300km of river course between Lyon (France) and the Mediterranean Sea. An indirect consequence could be a change in the flood dynamics along the channel course, caused by the simplification of the channel patterns and the floodplain accretion. This communication aims to assess the potential changes in the flood propagation along the middle and lower Rhône valley throughout a century of anthropogenic reconfigurations of the channel. The possible impact of these human pressures on the inundation risk and the attenuation of the flood peak discharge is also discussed. Through the use of digitized hydrometric data recorded since 1840 on multiple stream gauges of the Rhône river, a variety of floods of the same type and magnitude are selected. The oceanic flood types (as described by Pardé, 1925) that take their origin from heavy rainfalls upstream of the area of interest are preferred. Thus, complex flood waves due to floods from the lower Rhône valley tributaries are avoided, to keep the analysis as simple as possible. The flood travel time and the peak discharge attenuation of the selected events are compared over the years of channel transformations, permitting us to estimate the impact of anthropogenic pressures on the flood dynamics.</p>

Quantifying the impact of impervious surface location on flood peak discharge in urban areas

2015 ◽  
Vol 76 (3) ◽  
pp. 1457-1471 ◽  
Author(s):  
Shiqiang Du ◽  
Peijun Shi ◽  
Anton Van Rompaey ◽  
Jiahong Wen
Keyword(s):  
Urban Areas ◽  
Impervious Surface ◽  
Peak Discharge ◽  
Flood Peak ◽  
Surface Location ◽  
The Impact

scholarly journals Erratum: Kabeja, C., et al. The Impact of Reforestation Induced Land Cover Change (1990–2017) on Flood Peak Discharge Using HEC-HMS Hydrological Model and Satellite Observations: A Study in Two Mountain Basins, China. Water 2020, 12, 1347

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 676
Author(s):  
Crispin Kabeja ◽  
Rui Li ◽  
Jianping Guo ◽  
Digne Edmond Rwabuhungu Rwatangabo ◽  
Marc Manyifika ◽  
...  
Keyword(s):  
Land Cover ◽  
Land Cover Change ◽  
Hydrological Model ◽  
Satellite Observations ◽  
Peak Discharge ◽  
Flood Peak ◽  
Mountain Basins ◽  
The Impact

In the original article, there was a mistake in Figure 1 as published [...]

scholarly journals The Impact of Reforestation Induced Land Cover Change (1990–2017) on Flood Peak Discharge Using HEC-HMS Hydrological Model and Satellite Observations: A Study in Two Mountain Basins, China

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1347 ◽  
Author(s):  
Crispin Kabeja ◽  
Rui Li ◽  
Jianping Guo ◽  
Digne Edmond Rwabuhungu Rwatangabo ◽  
Marc Manyifika ◽  
...  
Keyword(s):  
Land Cover ◽  
Agricultural Land ◽  
Flash Flood ◽  
Peak Discharge ◽  
Substantial Impact ◽  
Flood Peak ◽  
Mountainous Regions ◽  
Hydrological Responses ◽  
Basin Scale ◽  
The Impact

Understanding the effect of land use and land cover (LULC) type change on watershed hydrological response is essential for adopting applicable measures to control floods. In China, the Grain to Green Program (GTGP) and the Natural Forest Conservation Program (NFCP) have had a substantial impact on LULC. We investigate the effect of these conservation efforts on flood peak discharge in two mountainous catchments. We used a series of Landsat images ranging from 1990 to 2016/2017 to evaluate the LULC changes. Further to this, the hydrological responses at the basin and sub-basin scale were generated by the Hydrologic Modeling System (HEC-HMS) under four LULC scenarios. Between 1990 and 2016/2017, both catchments experienced an increase in forest and urban land by 18% and 2% in Yanhe and by 16% and 8% in Guangyuan, respectively. In contrast, the agricultural land decreased by approximately 30% in Yanhe and 24% in Guangyuan, respectively. The changes in land cover resulted in decrease in flood peak discharge ranging from 14% in Yanhe to 6% in Guangyuan. These findings provide a better understanding on the impact of reforestation induced LULC change on spatial patterns of typical hydrological responses of mountainous catchment and could help to mitigate flash flood hazards in other mountainous regions.

scholarly journals The role of foliar litter-fall in forming channel morphology step-pool of high-gradient streams in Moravskoslezské Beskydy Mts.

Geografie ◽  
2017 ◽  
Vol 122 (1) ◽  
pp. 83-99 ◽  
Author(s):  
Libor Borák
Keyword(s):  
Grain Size ◽  
Woody Debris ◽  
Size Composition ◽  
Channel Morphology ◽  
Large Woody Debris ◽  
Litter Fall ◽  
Retention Capacity ◽  
Water Flows ◽  
The Impact

Channel morphology step-pool represents a morphodynamic complex influenced by large woody debris and litter-fall. The aim of this paper is to determine the impact of litter-fall on the channel morphology step-pool. General conclusions regarding the influence of litter-fall on channel morphology step-pool were based on results of geomorphological analyses. The study showed differences between river segments with or without foliaged steps. The pools following foliaged steps have a finer grain size composition of sediment. They are also larger, shallower and have a higher retention capacity. Foliaged steps help to decrease potential energy of water more effectively. If the litter-fall is permanently preserved at the step, it makes it more resistant to extreme water flows. As a result, it enables the development of a fully functional channel morphology step-pool.

scholarly journals Lightweight Cement Conglomerates Based on End-of-Life Tire Rubber: Effect of the Grain Size, Dosage and Addition of Perlite on the Physical and Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 225
Author(s):  
Andrea Petrella ◽  
Michele Notarnicola
Keyword(s):  
Grain Size ◽  
End Of Life ◽  
Compression Tests ◽  
Tire Rubber ◽  
Impact Compression ◽  
Weight Percentage ◽  
Deep Groove ◽  
Mechanical Strengths ◽  
The Impact ◽  
Thermal Conductivities

Lightweight cement mortars containing end-of-life tire rubber (TR) as aggregate were prepared and characterized by rheological, thermal, mechanical, microstructural, and wetting tests. The mixtures were obtained after total replacement of the conventional sand aggregate with untreated TR with different grain sizes (0–2 mm and 2–4 mm) and distributions (25%, 32%, and 40% by weight). The mortars showed lower thermal conductivities (≈90%) with respect to the sand reference due to the differences in the conductivities of the two phases associated with the low density of the aggregates and, to a minor extent, to the lack of adhesion of tire to the cement paste (evidenced by microstructural detection). In this respect, a decrease of the thermal conductivities was observed with the increase of the TR weight percentage together with a decrease of fluidity of the fresh mixture and a decrease of the mechanical strengths. The addition of expanded perlite (P, 0–1 mm grain size) to the mixture allowed us to obtain mortars with an improvement of the mechanical strengths and negligible modification of the thermal properties. Moreover, in this case, a decrease of the thermal conductivities was observed with the increase of the P/TR dosage together with a decrease of fluidity and of the mechanical strengths. TR mortars showed discrete cracks after failure without separation of the two parts of the specimens, and similar results were observed in the case of the perlite/TR samples thanks to the rubber particles bridging the crack faces. The super-elastic properties of the specimens were also observed in the impact compression tests in which the best performances of the tire and P/TR composites were evidenced by a deep groove before complete failure. Moreover, these mortars showed very low water penetration through the surface and also through the bulk of the samples thanks to the hydrophobic nature of the end-of-life aggregate, which makes these environmentally sustainable materials suitable for indoor and outdoor elements.

scholarly journals Erosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1540
Author(s):  
Qianqian Ji ◽  
Zhe Gao ◽  
Xingyao Li ◽  
Jian’en Gao ◽  
Gen’guang Zhang ◽  
...  
Keyword(s):  
Similarity Theory ◽  
Design Method ◽  
Simulation Method ◽  
Practical Significance ◽  
Land Consolidation ◽  
Small Watershed ◽  
Flood Peak ◽  
Erosion Area ◽  
The Impact ◽  
Erosion Environment

The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: λl = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW.

Sign in / Sign up

Export Citation Format

Share Document