Sediment Regimes in South Korea

This study provides a comprehensive review of the existing river measurement data of South Korea. The specific sediment yield in the country is 5–1,500 tons/km ·year. The watershed area decisively affects the shapes of the curves for flow duration, sediment rating, and cumulative distribution of water and sediment discharge, and it can determine the effects of topographic and anthropogenic characteristics on erosion and sedimentation processes. Regarding flow regime, small watersheds have flashy hydrographs and high sediment concentrations at a given flow discharge. The coefficient of the sediment rating curves for various rivers decreases from 1 to 0.02 as the watershed area increases from 100 to 20,000 km , with the exponent of the curves ranging from 1.5 to 2.0. Moreover, sediment transport in small watersheds depends on large floods. The half-yield discharge typically ranges from 5 to 40 times the mean discharge, and it decreases with increasing watershed area. This study proposes equations to calculate the annual discharges, flow duration curves, sediment yield, and cumulative distribution curves of the flow and sediment, as well as the sediment yield at reservoirs in South Korea. Additionally, the sediment regimes in the country are compared to those in other continental regions.

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Estimation of River Management Flow Considering Stream Water Deficit Characteristics

Water ◽

10.3390/w10111521 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1521

Author(s):

Jang Sung ◽

Seung Seo

Keyword(s):

South Korea ◽

Water Deficit ◽

Stream Water ◽

Threshold Level ◽

River Management ◽

Severe Drought ◽

Flow Duration ◽

Water Users ◽

Flow Duration Curves ◽

Management Flow

South Korea endured extreme drought through 2015 and 2016. This hydrological drought led to a socio-economic drought which is a restriction on stream water use. Previous studies have explored streamflow drought using a threshold level based on flow duration curves, but streamflow drought does not necessarily lead to stream water deficit, which is related to water demand. Therefore, this study introduced a threshold for stream water deficit in South Korea, which is termed as river management flow, and was applied to Geum River Basin where a severe drought recently occurred. The stream water coordination council has restricted the use of stream water to cope with the stream water deficit. The deficit characteristics for the upstream and downstream river management flow should be similar in order to ensure the feasibility of stream water restrictions. Thus, upstream and downstream river management flows, which reproduced similar deficit characteristics to those of the reference site, were estimated. The deficit characteristics of Bugang and Gyuam were estimated from their river management flows for the 2015 drought and were comparable to those of Gongju. We expect this study to minimize the conflict between upstream and downstream water users in future.

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Relationship of sediment yield to connectivity index in small watersheds with similar erosion potentials

Journal of Soils and Sediments ◽

10.1007/s11368-021-02978-z ◽

2021 ◽

Author(s):

Mahmood Arabkhedri ◽

Kohzad Heidary ◽

Mohammad-Reza Parsamehr

Keyword(s):

Sediment Yield ◽

Connectivity Index ◽

Small Watersheds ◽

Relationship Of

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Predicting annual and long-term flow-duration curves in ungauged basins

Advances in Water Resources ◽

10.1016/j.advwatres.2006.08.006 ◽

2007 ◽

Vol 30 (4) ◽

pp. 937-953 ◽

Cited By ~ 89

Author(s):

Attilio Castellarin ◽

Giorgio Camorani ◽

Armando Brath

Keyword(s):

Ungauged Basins ◽

Flow Duration ◽

Flow Duration Curves

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Exploring the physical controls of regional patterns of flow duration curves – Part 4: A synthesis of empirical analysis, process modeling and catchment classification

Hydrology and Earth System Sciences ◽

10.5194/hess-16-4483-2012 ◽

2012 ◽

Vol 16 (11) ◽

pp. 4483-4498 ◽

Cited By ~ 47

Author(s):

M. Yaeger ◽

E. Coopersmith ◽

S. Ye ◽

L. Cheng ◽

A. Viglione ◽

...

Keyword(s):

Low Flow ◽

Middle Portion ◽

Qualitative Synthesis ◽

Statistical Parameters ◽

Regional Patterns ◽

Flow Duration ◽

Analysis Process ◽

Wide Range ◽

Physical Controls ◽

Flow Duration Curves

Abstract. The paper reports on a four-pronged study of the physical controls on regional patterns of the flow duration curve (FDC). This involved a comparative analysis of long-term continuous data from nearly 200 catchments around the US, encompassing a wide range of climates, geology, and ecology. The analysis was done from three different perspectives – statistical analysis, process-based modeling, and data-based classification – followed by a synthesis, which is the focus of this paper. Streamflow data were separated into fast and slow flow responses, and associated signatures, and both total flow and its components were analyzed to generate patterns. Regional patterns emerged in all aspects of the study. The mixed gamma distribution described well the shape of the FDC; regression analysis indicated that certain climate and catchment properties were first-order controls on the shape of the FDC. In order to understand the spatial patterns revealed by the statistical study, and guided by the hypothesis that the middle portion of the FDC is a function of the regime curve (RC, mean within-year variation of flow), we set out to classify these catchments, both empirically and through process-based modeling, in terms of their regime behavior. The classification analysis showed that climate seasonality and aridity, either directly (empirical classes) or through phenology (vegetation processes), were the dominant controls on the RC. Quantitative synthesis of these results determined that these classes were indeed related to the FDC through its slope and related statistical parameters. Qualitative synthesis revealed much diversity in the shapes of the FDCs even within each climate-based homogeneous class, especially in the low-flow tails, suggesting that catchment properties may have become the dominant controls. Thus, while the middle portion of the FDC contains the average response of the catchment, and is mainly controlled by climate, the tails of the FDC, notably the low-flow tails, are mainly controlled by catchment properties such as geology and soils. The regime behavior explains only part of the FDC; to gain a deeper understanding of the physical controls on the FDC, these extremes must be analyzed as well. Thus, to completely separate the climate controls from the catchment controls, the roles of catchment properties such as soils, geology, topography etc. must be explored in detail.

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Annual flow duration curves assessment in ephemeral small basins

Journal of Hydrology ◽

10.1016/j.jhydrol.2014.07.024 ◽

2014 ◽

Vol 519 ◽

pp. 258-270 ◽

Cited By ~ 17

Author(s):

D. Pumo ◽

F. Viola ◽

G. La Loggia ◽

L.V. Noto

Keyword(s):

Flow Duration ◽

Flow Duration Curves

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Exploring the physical controls of regional patterns of flow duration curves – Part 1: Insights from statistical analyses

Hydrology and Earth System Sciences ◽

10.5194/hess-16-4435-2012 ◽

2012 ◽

Vol 16 (11) ◽

pp. 4435-4446 ◽

Cited By ~ 58

Author(s):

L. Cheng ◽

M. Yaeger ◽

A. Viglione ◽

E. Coopersmith ◽

S. Ye ◽

...

Keyword(s):

Gamma Distribution ◽

Classical Method ◽

Regional Patterns ◽

Flow Duration ◽

Total Runoff ◽

Time Symmetry ◽

Physical Controls ◽

Flow Duration Curves ◽

Predictions In Ungauged Basins ◽

Fast Flow

Abstract. The flow duration curve (FDC) is a classical method used to graphically represent the relationship between the frequency and magnitude of streamflow. In this sense it represents a compact signature of temporal runoff variability that can also be used to diagnose catchment rainfall-runoff responses, including similarity and differences between catchments. This paper is aimed at extracting regional patterns of the FDCs from observed daily flow data and elucidating the physical controls underlying these patterns, as a way to aid towards their regionalization and predictions in ungauged basins. The FDCs of total runoff (TFDC) using multi-decadal streamflow records for 197 catchments across the continental United States are separated into the FDCs of two runoff components, i.e., fast flow (FFDC) and slow flow (SFDC). In order to compactly display these regional patterns, the 3-parameter mixed gamma distribution is employed to characterize the shapes of the normalized FDCs (i.e., TFDC, FFDC and SFDC) over the entire data record. This is repeated to also characterize the between-year variability of "annual" FDCs for 8 representative catchments chosen across a climate gradient. Results show that the mixed gamma distribution can adequately capture the shapes of the FDCs and their variation between catchments and also between years. Comparison between the between-catchment and between-year variability of the FDCs revealed significant space-time symmetry. Possible relationships between the parameters of the fitted mixed gamma distribution and catchment climatic and physiographic characteristics are explored in order to decipher and point to the underlying physical controls. The baseflow index (a surrogate for the collective impact of geology, soils, topography and vegetation, as well as climate) is found to be the dominant control on the shapes of the normalized TFDC and SFDC, whereas the product of maximum daily precipitation and the fraction of non-rainy days was found to control the shape of the FFDC. These relationships, arising from the separation of total runoff into its two components, provide a potential physical basis for regionalization of FDCs, as well as providing a conceptual framework for developing deeper process-based understanding of the FDCs.

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