Contemporary Sediment Delivery Ratios for Small Catchments Subject to Shallow Rainfall Triggered Earthflows in the Waipaoa Catchment, North Island, New Zealand

Mapping Intimacies ◽

10.26686/wgtn.16968523 ◽

2021 ◽

Author(s):

◽

Katie Elizabeth Jones

Keyword(s):

River Mouth ◽

Storm Event ◽

Delivery Ratio ◽

Storm Events ◽

Spatial And Temporal Patterns ◽

Channel Coupling ◽

Sediment Delivery ◽

Catchment Size ◽

Fluvial Network ◽

Small Catchments

<p>The Waipaoa catchment is generally considered to have high hill slope channel coupling due to the large volumes of sediment output at the river mouth. Yet the percentage of sediment that is transported within the fluvial system is low when considered in terms of the total volume of sediment mobilised during episodic failure events. Clearly, there is a discrepancy between generation of sediment and its delivery to the fluvial network. Previous research has suggested there is a strong decrease in catchment connectivity as catchment size increases. However, little research has been undertaken to understand the changes in hillslope-channel coupling over time. This study focuses on the connectivity of shallow rainfall triggered earthflows located in small catchments located within three different land systems in the Waipaoa Catchment. A multiple regression model was developed to predict the sediment delivery ratio for individual earthflows based on an empirical dataset of earthflows which occurred during a storm event in 2002. The results from this modelling were applied to five larger sub-catchments where sequential aerial photograph analysis (1940s to 2004) was used to determine connectivity. From this, spatial and temporal patterns in the catchment sediment delivery ratios were identified. The expected decrease in sediment delivery ratios was observed as catchment size increased. However, the temporal pattern to sediment delivery is not so clear. It appears that catchment evolution, referring specially to the Terrain Event Resistance Model developed by Crozier and Preston (1999), does not have a significant influence on sediment delivery ratios within the six decades examined in this thesis. Furthermore, while earthflows are considered the ultimate source of sediment during storm events, they are not always the mechanism by which this sediment enters the fluvial network. It is also vital to consider rates of gullying, sheet erosion and riparian erosion.</p>

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Contemporary Sediment Delivery Ratios for Small Catchments Subject to Shallow Rainfall Triggered Earthflows in the Waipaoa Catchment, North Island, New Zealand

10.26686/wgtn.16968523.v1 ◽

2021 ◽

Author(s):

◽

Katie Elizabeth Jones

Keyword(s):

River Mouth ◽

Storm Event ◽

Delivery Ratio ◽

Storm Events ◽

Spatial And Temporal Patterns ◽

Channel Coupling ◽

Sediment Delivery ◽

Catchment Size ◽

Fluvial Network ◽

Small Catchments

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Introducing an appropriate empirical method for estimating sediment delivery ratio (SDR) via sedimentometry of check-dams in small catchments in arid regions (Semnan province, Iran)

Arabian Journal of Geosciences ◽

10.1007/s12517-021-07322-w ◽

2021 ◽

Vol 14 (12) ◽

Author(s):

Hossein Etemadi ◽

Shima Nikoo ◽

Seyed Ali Asghar Hashemi

Keyword(s):

Arid Regions ◽

Empirical Method ◽

Delivery Ratio ◽

Sediment Delivery Ratio ◽

Sediment Delivery ◽

Check Dams ◽

Small Catchments ◽

Semnan Province

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Spatial and temporal patterns of off-slope sediment delivery for small catchments subject to shallow landslides within the Waipaoa catchment, New Zealand

Geomorphology ◽

10.1016/j.geomorph.2011.12.037 ◽

2012 ◽

Vol 141-142 ◽

pp. 150-159 ◽

Cited By ~ 16

Author(s):

Katie E. Jones ◽

Nicholas J. Preston

Keyword(s):

New Zealand ◽

Temporal Patterns ◽

Shallow Landslides ◽

Spatial And Temporal Patterns ◽

Sediment Delivery ◽

Slope Sediment ◽

Small Catchments

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Estimation of annual pollutant loadings in two small catchments and examination of their differences caused by regional properties

Water Science & Technology ◽

10.2166/wst.2006.036 ◽

2006 ◽

Vol 53 (2) ◽

pp. 33-44 ◽

Cited By ~ 2

Author(s):

S. Fujii ◽

M. Moriya ◽

P. Songprasert ◽

H. Ihara

Keyword(s):

River Basin ◽

High Frequency ◽

Storm Event ◽

Precipitation Pattern ◽

Storm Events ◽

Rainfall Events ◽

Survey Results ◽

One Year ◽

Small Catchments

A series of runoff surveys was conducted for more than one year in two small catchments of the Kamo River basin (75.4 km2) and the Takano River basin (66.8 km2) in Kyoto, Japan, which adjoin each other, and may have the same precipitation pattern. The investigation consisted of a high-frequency periodic survey, a long-term regular survey and a storm event survey. The survey results were compared with the regional properties of the basins, and the following results were obtained. (1) Pollutant loadings were successfully estimated as two portions of base discharge and storm events discharge from the survey results. (2) Estimated annual loading of the sites was 2.9–4.5, 1.3–1.8, 17–27, 1.3–2.2, 0.076–0.97 t/km2/y, respectively for CODMn, DOC, SS, TN and TP. (3) 52–53% of the whole flow, which was caused by rainfall events, conveyed 81–87, 68–73, 92–95, 64–67, 76–81% of the whole loading, respectively for CODMn, DOC, SS, TN and TP. (4) Differences of regional properties in two basins cause different runoff patterns, but the differences in runoff patterns also depend on the rainfall patterns. In general, a more urbanized basin receives early and strong influence of precipitation on the storm event runoff.

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Efficacy of Time-Area Method in simulating temporal variation of sediment yield in Chehelgazi watershed, Iran

Annals of Warsaw University of Life Sciences – SGGW Land Reclamation ◽

10.2478/v10060-008-0064-8 ◽

2010 ◽

Vol 42 (1) ◽

pp. 51-60 ◽

Cited By ~ 3

Author(s):

A. Darvishan ◽

S. Sadeghi ◽

L. Gholami

Keyword(s):

Temporal Variation ◽

Sediment Yield ◽

Water Conservation ◽

Delivery Ratio ◽

Storm Events ◽

Temporal And Spatial Variation ◽

Sediment Delivery ◽

Sediment Control ◽

Area Method ◽

Temporal And Spatial

Efficacy of Time-Area Method in simulating temporal variation of sediment yield in Chehelgazi watershed, Iran The proper prediction of temporal and spatial variation of sediment yield from the watershed is a need for sediment control, river engineering and soil and water conservation studies. The present study was therefore planned to simulate the sediment graphs for Chehelgazi watershed in Gheshlagh dam upstream in Kurdistan Province, Iran, by using Time-Area Method. Towards this attempt, the study watershed was divided into 7 time-area segments based on the time of concentration. The soil erosion in each segment was estimated using the USLE and then routed to the main outlet using sediment delivery ratio as a function of land slope in two adjacent time-areas. The temporal variation of sediment was ultimately predicted with the help of lag time of sediment arrival to the outlet and the concept of superposition for 11 storm events, which occurred during winter 2006 and spring 2007. The comparison between estimated sediment graphs with corresponding observed ones verified the weak capability of the model in simulation of sediment graphs under consideration. The results also verified the calibration necessity of the model to achieve appropriate estimation for important components of the sediment graphs. The results of the calibration finally proved the considerable capability of the model in predicting of total volume of sediment yield with respective estimation and verification errors of 30.93 and 33.40%.

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Review on uncertainty of the first-flush phenomenon in diffuse pollution control

Applied Water Science ◽

10.1007/s13201-019-1127-1 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 5

Author(s):

Abdullah Al Mamun ◽

Shahriar Shams ◽

Md. Nuruzzaman

Keyword(s):

Best Management Practices ◽

Management Practices ◽

Nonpoint Source ◽

Diffuse Pollution ◽

Storm Runoff ◽

Storm Event ◽

First Flush ◽

Storm Events ◽

Treatment Facility ◽

Small Catchments

AbstractSeveral definitions and criteria of the first-flush are being used to assess and control the nonpoint source (diffuse) pollution. The common consensus is that the first-flush is generally noticed in the small catchments (e.g. < 10 ha) of regular shapes. It is also considered that 80% of the pollution load can be captured by capturing 30% of the runoff volume, which is assumed to be due to first-flush of the storm event. However, such phenomenon is uncertain in the considerably large catchments, principally due to the dilution and delay in transport of the pollutant. This paper critically examines the ‘first-flush’ phenomenon in controlling diffuse pollution based on various studies conducted by the researchers. Based on the review, it can be inferred that the first-flush may be an effective criterion for sizing on-site treatment facilities for small catchments (with similar dimensions of length and width), from where the runoff is expected to reach the treatment facility (roughly) at the same time. However, for the large and elongated catchments with an area covering more than 10 ha, a huge volume of storm runoff needs to be captured that would make the treatment system large or less effective. As such, for the community and regional facilities; the presence of the first-flush needs to be confirmed based on the sampling and analysis of data collected from several storm events of different durations and intensities. Therefore, the use of the first-flush phenomenon should not be applied for the design of storm runoff treatment facility in large drainage system (say > 10 ha) without on-site monitoring being conducted. However, it is also recommended to come up with a simplistic approach of designing the best management practices (BMPs) to capture and treat certain depth of the initial storm runoff (e.g. first 20 mm), which will help reduce the effect of nonpoint source (NPS) pollution.

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KAJIAN EROSI LAHAN DI KAWASAN AIR STRIP RUNWAY 2600 BANDARA DEPATI AMIR (PGK) BERDASARKAN TATA GUNA LAHAN MASTERPLAN ULTIMATE

FROPIL (Forum Profesional Teknik Sipil) ◽

10.33019/fropil.v7i2.1627 ◽

2019 ◽

Vol 7 (2) ◽

pp. 100-111

Author(s):

Miskar Maini ◽

Junita Eka Susanti

Keyword(s):

Sediment Yield ◽

Soil Loss ◽

Universal Soil Loss Equation ◽

Delivery Ratio ◽

Sediment Delivery Ratio ◽

Sediment Delivery ◽

Soil Loss Equation

Standar permintaan engineering pesawat agar desain bangunan infrastruktur di area Air Strip Runway 2600 yang ada dapat mempunyai fungsi lain. Sedangkan kondisi lain sangat menentukan keselamatan karena lahan di sekitar Air Strip Runway 2600 Bandara Depati Amir (PGK) jika tidak ditutupi vegetasi seperti rumput, kondisi lain lahan yang belum ditutupi vegetasi di sekitar Air Strip Runway 2600 berpotensi akan mengalami erosi lahan, kemudian hasil erosi lahan ini akan terbawa oleh aliran air sehingga akan masuk ke saluran drainase yang akan menyebabkan sedimentasi pada saluran drainase tersebut, akhirnya akan berkurang efektifitas kinerja saluran drainase tersebut. Metode yang digunakan untuk memprediksi laju rata-rata erosi di area Air Strip Runway 2600 dengan memperhitungkan faktor erosivitas hujan, erodibilitas tanah, kemiringan lereng atau panjang lereng, pengelolaan tanaman dan konservasi tanah, yang masing masing tata guna lahan tersebut mengacu pada Masterplan Ultimate Bandara Depati Amir (PGK). Perhitungan dilakukan menggunakan persamaan USLE (Universal Soil Loss Equation) yang dikembangkan oleh Wischmeier dan Smith (1965, 1978), kemudian Sediment Delivery Ratio (SDR) dan Sediment Yield.Hasil penelitian ini, prediksi laju erosi permukaan pada area Air Strip Runway 2600 Bandara Depati Amir (PGK) tahun pertama yang mencapai 5,60 mm/tahun atau 100,76 Ton/Ha/tahun, laju erosi tahun kedua mencapai 3,38 mm/tahun atau 60,84 Ton/Ha/tahun dapat diklasifikasikan ke dalam kelas bahaya erosi sedang (kelas III) dan nilai SDR adalah sebesar 56,3%, nilai sediment yield (SR) pada tahun pertama sebesar 5.887,59 Ton/Tahun, pada tahun kedua ketika rumput pada area Air Strip telah tumbuh dengan sempurna terjadi penurunan hasil sediment yield yaitu nilai SR sebesar 3.554,85 Ton/Tahun.

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Factors influencing the sediment delivery ratio of the Three Gorges Reservoir

E3S Web of Conferences ◽

10.1051/e3sconf/20184003019 ◽

2018 ◽

Vol 40 ◽

pp. 03019

Author(s):

Dayu Wang ◽

Chunhong Hu ◽

Chunming Fang ◽

Jianzhao Guan ◽

Lei Zhang

Keyword(s):

Sensitivity Analysis ◽

Three Gorges Reservoir ◽

Delivery Ratio ◽

Three Gorges ◽

Sediment Delivery Ratio ◽

Sediment Delivery ◽

Shape Coefficient ◽

The Three Gorges Reservoir ◽

The Three Gorges ◽

Dam Site

In recent years, the sediment delivery ratio (SDR) of the Three Gorges reservoir (TGR) has noticeably decreased as a result of the increase in water levels at the dam site and the decrease in inflow of fine particles, thereby resulting in increased reservoir siltation. Therefore, it is vital to research the factors that influence the SDR of the TGR. Factors that could have impact on the SDR were studied using TGR monitoring data. The study indicated that the water level at the dam site and inflow and outflow rates could have contributed to the change in the SDR. A sensitivity analysis of the influencing factors was then carried out using a mathematical model to simulate numerous sediment movement scenarios in the TGR. By changing the input conditions of the model, sufficient results were obtained to enable a sensitivity analysis of each factor. The results showed the flood retention time (FRT)—the ratio of reservoir capacity to average outflow discharge—was the principal factor influencing the SDR. The other factors (inflow sediment concentration, inflow sediment coefficient, inflow sediment gradations, and the shape coefficient of the inflow flood shape coefficient), also had an influence on the SDR. However, under different levels of FRT, their degrees of influence on the SDR were not the same..

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The effects of the big storm events in the first half of 2015 on the radiation belts observed by EPT/PROBA-V

Annales Geophysicae ◽

10.5194/angeo-34-75-2016 ◽

2016 ◽

Vol 34 (1) ◽

pp. 75-84 ◽

Cited By ~ 10

Author(s):

V. Pierrard ◽

G. Lopez Rosson

Keyword(s):

Charged Particle ◽

High Resolution ◽

Geomagnetic Storm ◽

Energetic Particle ◽

High Energy ◽

Radiation Belts ◽

Radiation Environment ◽

Storm Event ◽

Storm Events ◽

Particle Radiation

Abstract. With the energetic particle telescope (EPT) performing with direct electron and proton discrimination on board the ESA satellite PROBA-V, we analyze the high-resolution measurements of the charged particle radiation environment at an altitude of 820 km for the year 2015. On 17 March 2015, a big geomagnetic storm event injected unusual fluxes up to low radial distances in the radiation belts. EPT electron measurements show a deep dropout at L > 4 starting during the main phase of the storm, associated to the penetration of high energy fluxes at L < 2 completely filling the slot region. After 10 days, the formation of a new slot around L = 2.8 for electrons of 500–600 keV separates the outer belt from the belt extending at other longitudes than the South Atlantic Anomaly. Two other major events appeared in January and June 2015, again with injections of electrons in the inner belt, contrary to what was observed in 2013 and 2014. These observations open many perspectives to better understand the source and loss mechanisms, and particularly concerning the formation of three belts.

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