Effect of cattle treading on interrill erosion from hill pasture: modelling concepts and analysis of rainfall simulator data

Soil Research ◽  
2002 ◽  
Vol 40 (6) ◽  
pp. 963 ◽  
Author(s):  
A. H. Elliott ◽  
Y. Q. Tian ◽  
J. C. Rutherford ◽  
W. T. Carlson
Keyword(s):  
Hydraulic Conductivity ◽  
Sediment Concentration ◽  
Reduction Factor ◽  
Bare Ground ◽  
Infiltration Capacity ◽  
Rainfall Simulator ◽  
Hill Country ◽  
Sediment Loads ◽  
Interrill Erosion ◽  
Using Data

Damage to pasture as a result of intensive grazing and treading by cattle increases the erosion of sediment and associated nutrients. In this study we present a model for the effect of treading damage on interrill erosion. The model formulation is based on the interrill erosion components of conventional process-based erosion models, with some modifications. The model was developed using data from small rainfall simulator plots (0.5 m2) on hill-country pasture in New Zealand with varying amounts of treading damage. Treading increased the amount of bare ground, and this resulted in increased concentrations of sediment in runoff. Concentration was found to increase linearly with the amount of bare ground. Treading resulted in increased runoff, which had some effect on sediment concentration for the high runoff rates in the experiments, but would have a negligible effect on concentration for typical natural runoff rates. However, the increased runoff results in greater sediment loads because a larger volume of sediment-laden runoff is produced. The increase in runoff was modelled through a reduction factor for the hydraulic conductivity which varied linearly with the fraction of damaged ground. For 100% damaged ground the hydraulic conductivity was approximately halved. The recovery of bare ground and damaged ground over time after treading was also assessed. Bare ground resulting from treading typically halved after 2 months, while damage took longer to recover. Such treading-related effects are superimposed on seasonal variations in erodibility, bare ground, and infiltration capacity. Based on the results of the study, some measures to reduce treading-related erosion are suggested.

scholarly journals Curvas-chave de descargas de sedimentos em suspensão no Baixo São Francisco

2020 ◽  
Vol 13 (3) ◽  
pp. 1248 ◽  
Author(s):  
Solange Cavalcanti de Melo ◽  
José Coelho de Araújo Filho ◽  
Renata Maria Caminha Mendes de Oliveira Carvalho
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Gradual Reduction ◽  
Sao Francisco River ◽  
Sediment Loads ◽  
São Francisco River ◽  
Historical Series ◽  
Suspended Sediment Concentrations

RESUMOO conhecimento da análise quantitativa das concentrações de sedimentos em suspensão transportados pelo rio São Francisco bem como sua relação com as vazões é de muita importância, pois pode auxiliar na identificação dos efeitos da intervenção humana e ou ocasionados pelas condições naturais da região. As regiões a jusante dos barramentos no rio São Francisco apresentam como principal consequência a regularização das vazões e a diminuição das concentrações de sedimentos. O objetivo da pesquisa foi determinar as curvas-chave de sedimentos em suspensão (CCS) nas estações fluviométricas instaladas no Baixo São Francisco (BSF) após a barragem de Xingó. Para o estabelecimento dessas curvas foram utilizados dados de vazão e concentração de sedimentos em suspensão, obtidos do sistema Hidroweb no site da Agência Nacional da Água (ANA) no período de 1999 a 2018. Foram obtidas CCS para todo o trecho do BSF as quais apresentaram bons coeficientes de determinação. Na análise dos dados também foi possível perceber que nos últimos anos, desde 2013 houve redução gradativa das vazões disponibilizadas na barragem de Xingó. Consequentemente, houve também a redução gradativa das cargas de sedimentos em suspensão geradas nas estações de Piranhas, Traipu e Propriá, ou seja, os menores valores já registrados no BSF correspondendo as menores séries históricas tanto de vazão como de sedimentos em suspensão.  Keys curves of sediment discharges in suspension in the Lower São Francisco A B S T R A C TThe knowledge of the quantitative analysis of suspended sediment concentrations carried by the São Francisco River as well as its relation with the flows is of great importance, since it can help in the identification of the effects of human intervention and/or caused by the natural conditions of the region. In the downstream regions of the São Francisco riverbanks, the main consequence was the regularization of flow rates and the reduction of sediment concentrations. The objective of the research was to determine the key curves of suspended sediments (CCS) at the fluviometric stations installed in the lower São Francisco river after Xingó dam. For the evaluation, flow data and suspended sediment concentration were used. These data were obtained from the Hidroweb system on the website of the National Water Agency (ANA) from 1999 to 2018. CCS were plotted for all stretches and presented good coefficients of determination (R2). Based on the analysis of the data it was also possible to notice that in recent years, since 2013 there has been a gradual reduction of the flows available in the Xingó dam. Consequently, there was also a gradual reduction of suspended sediment loads generated at the Piranhas, Traipu and Propriá stations, that is, the lowest values already recorded in lower São Francisco, corresponding to the lower historical series of both discharge and suspended sediments.Keywords: dam, flow, sediments 

Resilient pastures and sediment: a case study in Hawke's Bay

2021 ◽  
Vol 17 ◽  
Author(s):  
Dave Read
Keyword(s):  
Forest Cover ◽  
Single Species ◽  
Independent Research ◽  
Bare Ground ◽  
Hill Country ◽  
Regulatory Issue ◽  
Sediment Loss ◽  
Return On Capital

For many hill-country farms sediment will be a bigger regulatory issue than nitrates over the next decade. A dense, resilient pasture can reduce the risk of insidious sediment loss. Any ecosystem that relies on a few species is fragile. Sowing a single species leads to repeated re-sowing and increasing bare ground to remove competition, increasing the risk of sediment flows. An important issue during regulatory consultation will be establishing a natural, pre-human baseline for forest cover and documenting more recent changes in sediment flows. Hill country cropping and pasture renewal is incompatible with resilient pasture. This is a farmer’s perspective on a diverse and persisting hill country pasture-based system that can make a good return on capital without re-grassing or fodder cropping. Funding of independent research on pasture and fodder systems is essential if farmers are to make good decisions.

The contribution of the mallet hill surface to runoff and erosion in the Narrogin region of Western Australia

Soil Research ◽  
1980 ◽  
Vol 18 (3) ◽  
pp. 299 ◽  
Author(s):  
DA Mcghie
Keyword(s):  
Hydraulic Conductivity ◽  
Western Australia ◽  
Aerial Photograph ◽  
Surface Soil ◽  
Early Years ◽  
Rainfall Simulator ◽  
Severe Erosion ◽  
Area Use ◽  
Water Repellence ◽  
Sheet Erosion

Severe erosion in the Great Southern area of Western Australia has long been associated with the land class known locally as the 'mallet hill'. This association was confirmed by means of an aerial photograph survey of a representative part of the area. Use of a recycling rainfall simulator showed the mallet hill land class to yield far higher runoff than any of four adjacent upper landscape surfaces. Several factors were thought to contribute to the higher runoff from the mallet hill surface. Among these were steeper slopes, a heavier texture and water repellence of the surface soil which varied from severe in the virgin and freshly cleared state to slight or non existent in soils, which had been cleared for many years. No assessment of the relative contributions of the various factors was made, although it appeared likely that water repellence would be more important in the early years after clearing. Removal of the topsoil by sheet erosion would increase the importance of the low hydraulic conductivity of the heavy-textured subsoil in causing runoff.

scholarly journals An application of adaptive cluster sampling for estimating total suspended sediment load

2009 ◽  
Vol 41 (1) ◽  
pp. 63-73 ◽  
Author(s):  
M. Arabkhedri ◽  
F. S. Lai ◽  
I. Noor-Akma ◽  
M. K. Mohamad-Roslan
Keyword(s):  
Suspended Sediment ◽  
Sediment Concentration ◽  
Cluster Sampling ◽  
Suspended Sediment Transport ◽  
Adaptive Cluster Sampling ◽  
Total Load ◽  
Sediment Rating Curve ◽  
Sediment Loads ◽  
Daily Concentration ◽  
Rating Curves

Suspended sediment transport in river for a particular period is a timescale finite population. This population shows natural aggregation tendencies in sediment concentration particularly during floods. Adaptive cluster sampling (ACS) can be potentially conducted for sampling from this rare clustered population and estimating total load. To illustrate the performance of ACS in sediment estimation, a comparative study was carried out in the Gorgan-Rood River, Iran, with around a 5 year daily concentration record. The total sediment loads estimated by ACS were statistically compared to the observed load, estimations of selection at list time (SALT) and conventional sediment rating curve with and without correction factors. The results suggest that none of the sediment rating curves produced accurate estimates, while both ACS and SALT showed satisfactory results at a semi-weekly sampling frequency. The best estimation obtained by the rating curves did not show a percent error better than −40%; however, ACS and SALT underestimated the load at less than 5%. The results of this study suggest ACS could improve river monitoring programs.

Single-station estimates of suspended sediment loads using sediment rating curves

1993 ◽  
Vol 20 (1) ◽  
pp. 133-143 ◽  
Author(s):  
David Hansen ◽  
Dale I. Bray
Keyword(s):  
Suspended Sediment ◽  
Sediment Concentration ◽  
Ordinary Least Squares ◽  
Least Squares Regression ◽  
Concentration Data ◽  
Data Set ◽  
Sediment Loads ◽  
Single Station ◽  
Rating Curves ◽  
River Cross Section

Sediment rating curves in conjunction with daily flow data have often been used to estimate the total mass of sediment flowing past a given river cross section over relatively long periods of time. Techniques are presented that seek to make the best use of limited noncontinuous suspended sediment concentration data to generate nine partial years of suspended sediment load by means of sediment rating curves for the Kennebecasis River, N.B. (drainage area of 1100 km2). Initially, the data were partitioned in an attempt to improve correlations between concentration and discharge. Such partitioning by season, month, periods of rising stage, and periods of falling stage did not uniformly improve correlations as compared with the correlations for nonpartitioned data. Various combinations of less well-known methods were then used, including a moving intercept method that makes greater use of point concentration observations in time, and correction factor methods for simple power-type relations as suggested by Ferguson and by Duan. In addition, the validity of some of the underlying assumptions for performing ordinary least-squares regression is examined for this data set. Finally, the effect of daily flow averaging on the computed load was examined and found to be small for this basin. Key words: suspended sediment, C–Q rating curves, flow averaging, washload estimates, statistical bias, regression estimates.

scholarly journals Assessment of soil infiltration capacity by using portable rainfall simulator

2015 ◽  
pp. 31-41 ◽  
Author(s):  
Yu. P. Sukhanovskii ◽  
V. A. Vitovtov ◽  
A. V. Prushchik ◽  
Yu. A. Solov`eva ◽  
S. I. Sanzharova
Keyword(s):  
Soil Infiltration ◽  
Infiltration Capacity ◽  
Rainfall Simulator

Erosion mechanisms in combined sewers and the potential for pollutant release to receiving waters and water treatment plants

2002 ◽  
Vol 45 (3) ◽  
pp. 61-69 ◽  
Author(s):  
T.D. Mcllhatton ◽  
R. Sakrabani ◽  
R.M. Ashley ◽  
R. Burrows
Keyword(s):  
Initial Period ◽  
Suspended Sediments ◽  
Field Studies ◽  
Sediment Concentration ◽  
Storm Event ◽  
Receiving Waters ◽  
Using Data ◽  
Erosion Mechanisms ◽  
Maintenance Requirements

The problems associated with solids in sewerage systems result in common difficulties such as blockages and flooding and the subsequent maintenance requirements have been well documented. Concerns regarding pollutant release have also been demonstrated, with the contribution from in-sewer solids to the quality of the flow during a storm event being especially significant. These events known as “foul flushes” in combined sewers typically occur in the initial period of storm flows, when the concentration of suspended sediments and other pollutants are significantly higher than at other times. Traditionally impacts from these events have been related to the suspended solids phase of the flow passing through a CSO structure. It is now apparent that much of the suspended load originates from solids eroded from the bed. The “near bed solids” which are re-entrained into the flow, together with solids eroded from the bulk bed, account for large changes in the suspended sediment concentration under time varying flow conditions. The influence of these eroded solids and their potential impact on receiving waters and treatment plants will be reviewed using data obtained from field studies carried out in the main Dundee interceptor sewer in Scotland. This paper describes some of the methods employed to investigate the characteristics of the pollutants associated with solids erosion in combined sewers.

PECULIARITIES OF THE SAND PARTICLES SUSPENDING UNDER INFLUENCE OF THE REGULAR WAVES

2018 ◽  
Author(s):  
М. Крыленко ◽  
M. Krylenko ◽  
Й. Грюне ◽  
Y. Gryune ◽  
Р. Косьян ◽  
...  
Keyword(s):  
Laboratory Experiment ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Time Interval ◽  
Regular Waves ◽  
Large Wave ◽  
Wave Channel ◽  
Sand Particles ◽  
Using Data

In the presented paper some peculiarities of suspending and distribution of sand particles under influence of the regular waves in time interval less than the wave period are discussed using data from laboratory experiment “Hannover 2008”. The experiment was carried out in the Large Wave Channel (GWK). The presented data show that fluctuations of suspended sediment concentration are very largely initiated by individual waves.

A Comparative assessment of estimated soil hydraulic conductivity from rainfall simulator and infiltrometer using laboratory repacked soil samples

2021 ◽  
Author(s):  
Aparimita Priyadarshini Naik ◽  
Sreeja Pekkat
Keyword(s):  
Hydraulic Conductivity ◽  
Comparative Assessment ◽  
Evaluation Methodology ◽  
Soil Pressure ◽  
Rainfall Simulator ◽  
Near Surface ◽  
Mean Values ◽  
Soil Hydraulic Conductivity ◽  
Significant Difference ◽  
Soil Hydraulic

<p>Near surface soil hydraulic conductivity is an essential parameter for various hydrological, geotechnical, and environmental-related studies. Currently, many instruments are in practice for evaluating this parameter, both in field, and laboratory. The rainfall simulator (RS) and mini disc infiltrometer (MDI) are two instruments used for the indirect estimation of hydraulic conductivity by many researchers and engineers. However, both the devices differ in their working philosophy and evaluation methodology. While the RS works by considering large soil volumes and providing a positive soil pressure, the MDI works for small sampled volumes and supply negative boundary head. Therefore, the two devices can result in varying estimates of hydraulic conductivity. In this study, a comparative assessment is carried out between the saturated hydraulic conductivity (K<sub>s</sub>) estimates from the two instruments using laboratory experiments for two different soil textures (loam and sand). The infiltration results from the RS are analyzed using the Green-Ampt method, and from the MDI is analyzed using the Zhang's method followed by the Kutilek and Nielson method to produce K<sub>s</sub> values. The K<sub>s</sub> results from both the instruments are compared with the values obtained using the laboratory falling-head permeameter test. A one-way ANOVA and the Fisher’s Least Significant Difference (LSD) test as a posthoc test are carried out to analyze the statistical significance of the differences in the estimates of K<sub>s</sub> by the two devices. The results showed that the two devices produced varying K<sub>s</sub> results for both the soil textures, with the MDI mean values being one order higher than the RS mean. Compared with the permeameter values, the mean values from the RS were closer to the permeameter than the MDI. However, the ANOVA test and the Fisher’s LSD test reported that the variations between the two devices with that of the permeameter were not significant for both the soil textures. On the other hand, the RS and MDI variations were reported significant by the ANOVA and post hoc test.</p>

scholarly journals Sediment concentration rating curves for a monsoonal climate: upper Blue Nile

SOIL ◽  
2016 ◽  
Vol 2 (3) ◽  
pp. 337-349 ◽  
Author(s):  
Mamaru A. Moges ◽  
Fasikaw A. Zemale ◽  
Muluken L. Alemu ◽  
Getaneh K. Ayele ◽  
Dessalegn C. Dagnew ◽  
...  
Keyword(s):  
Geographical Area ◽  
Type Equation ◽  
Sediment Concentration ◽  
Rating Curve ◽  
Monsoon Period ◽  
Blue Nile ◽  
Sediment Loads ◽  
Blue Nile Basin ◽  
Rating Curves ◽  
Sediment Data

Abstract. Information on sediment concentration in rivers is important for design of reservoirs and for environmental applications. Because of the scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile Basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decreases linearly with effective rainfall towards source-limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100 ha watersheds for which historic data were available. The results show that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.

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