Kwanghun Choi

Changhyeon Lee

Won Kim

Sanghoon Shin

Soohyun Yang

Youngchan Kim

Yin San Woo

Hyon gseok Kang

Sanghyeon Yoo

Yuanming Hu

Dongwoon Kang

Revalin Herdianto

Jongmin Byun

The Riverscape Dynamics Laboratory investigates riverine landscape evolution, incorporating hydrological, geomorphological, and ecological processes.

Riverscape Dynamics Laboratory는 수문학적, 지형학적, 생태학적 과정을 통합하여 하천 지형의 진화를 연구한다.

Estimation of catchment-scale evapotranspiration with the simple method based on the maximum entropy production principle

Canopy box framework to represent the surface energy partitioning over vegetated areas

Equilibrium states of humid catchments satisfying both energy and mass conservations

Qualitative assessment model for longitudinal riverbed erosion and deposition based on suspended sediment impacts and hydraulic geometry relationship

Complementary relationship among heat flux ratios and maximum entropy production principle in humid forests

Power law between the apparent drainage density and the pruning area

On the nonlinearity of the catchment instantaneous response function: Insights obtained from dynamic wave modeling

Optimal combinations of global evapotranspiration and terrestrial water storage products for catchment water balance

Combining topography and reflectance indices for better surface water detection

The development process of the Korean coastal mountain range: Examination from spatial distribution of knickzones

Simulating the evolution of the topography–climate coupled system

Power laws in intra-storm temporal rainfall variability

Network topology and rainfall controls on the variability of combined sewer overflows and loads

Multicriteria Optimization Model to Generate on‐DEM Optimal Channel Networks

Globally universal fractal pattern of human settlements in river networks

Channel geometry controls downstream lags in sediment rating curves

Building a flood-warning framework for ungauged locations using low resolution, open-access remotely sensed surface soil moisture, precipitation, soil, and topographic information

Functional topology of evolving urban drainage networks

Small profile concavity of a fine-bed alluvial channel

New findings on river network organization: Law of eigenarea and relationships among Hortonian scaling ratios

An improved method for single flow direction calculation in grid digital elevation models

Reconstructing daily evapotranspiration data from multi-annual water budget using insolation and precipitation presence

Recent recovery of surface wind speed after decadal decrease: a focus on South Korea

Optimal sampling network for monitoring the representative water quality of an entire reservoir on the basis of information theory

Optimal location of basin‐wide constructed washlands to reduce risk of flooding

Efficient method for optimal placing of water quality monitoring stations for an ungauged basin

Relationship between downstream hydraulic geometry and suspended sediment concentration characteristics

Transitional responses of vegetation activities to temperature variations: Insights obtained from a forested catchment in Korea

Search for the optimality signature of river network development

Microtopography alters self‐organized vegetation patterns in water‐limited ecosystems

Simulation of landscape evolution using a global flow path search method

Optimization approach for 4-D natural landscape evolution

Power-law behavior in geometric characteristics of full binary trees

Optimality approaches to describe characteristic fluvial patterns on landscapes

Reply to comment by Stefano Orlandini and Giovanni Moretti on “Global search algorithm for nondispersive flow path extraction”

Global search algorithm for nondispersive flow path extraction

Analytical derivation of reservoir routing and hydrological risk evaluation of detention basins

Emergence of self‐similar tree network organization

Inevitable self-similar topology of binary trees and their diverse hierarchical density

A conceptual rainfall‐runoff model considering seasonal variation

Hydraulic geometry and the nonlinearity of the network instantaneous response

Changing climate in our lifetime: A review

Deriving channel width-discharge relationship from remote sensing imagery and digital elevation models

Influence of Spatial Rainfall Distribution on Sediment Yield: An Experimental Study

Comparison of RUSLE and LISEM for the Evaluation of Spatial Distribution of Simulated Sediment Yield

Statistical characteristics and stochastic modeling of water quality data at the influent of Daejeon wastewater treatment plant

Use of a harmony search for optimal design of coffer dam drainage pipes

Analysis of Temperature Change in April at Taegu City by Applying Multiple Intervention Model

Investigation of the variability in rainfall-runoff relationships

New findings on river network organization: Law of eigenarea and relationships among hortonian scaling ratios

Gavan McGrath

PSC Rao

Praveen Kumar

Joong Hoon KIM

Christian Urich

Elisabeth H. Krueger

James W Jawitz

Christoph Hinz

Hung Soo Kim, 김형수

Seokhyeon Kim

Alberto Montanari

Serena Ceola

Thomas Kaeseberg

Peter Krebs

Borchardt Dietrich

Fiona Johnson

Ashish Sharma

DAEHONG KIM

Kyungrock Paik

We investigate the multi-decadal variability of observed surface wind speed around South Korea. It is found that surface wind speed exhibits decreasing trend from mid-1950s until 2003, which is similar with the trends reported for other parts of the world. However, the decreasing trend ceases and becomes unclear since then. It is revealed that decreasing wind speed until 2003 is strongly associated with the decreasing trend of the spatial variance in both atmospheric pressure and air temperature across the East Asia for the same period. On the contrary, break of decreasing trend in surface wind speed since 2003 is associated with increasing spatial variance in surface temperature over the East Asia. Ground observation shows that surface wind speed and air temperature exhibit highly negative correlations for both summer and winter prior to 2003. However, since 2003, the correlations differ between seasons. We …

Among various deterministic rainfall‐runoff models, the tank model, which is a typical conceptual rainfall‐runoff model, is often preferred for its simple concepts. On the other hand, it requires much time and effort to obtain better results owing to the need to calibrate a large number of parameters in the model. Therefore, the demand for an automatic calibration method has been increasing. In this study, three optimization algorithms were tested for automatic calibration: one nonlinear programming algorithm (Powell's method) and two meta‐heuristic algorithms, i.e. a genetic algorithm and harmony search. The success of the powerful heuristic optimization algorithms enables researchers to focus on other aspects of the tank model rather than parameter calibration. The seasonal tank model is devised from the concept that seasonally different watershed responses could be reflected by seasonally different parameter …

River networks play a key role in the spatial organization of human settlements. Both river networks and human settlements have been found to exhibit regular self‐similar patterns, but little is known about the generalized spatial patterns of human settlements embedded within river networks. Here based on night light data, we find a universal fractal structure at the global scale, with both robust Hortonian scaling relationships with the extent of human settlements and statistically significant power law scaling of the power spectra of human area functions. Globally, we find consistent patterns of power law preferential downstream clustering of human settlements across all six populated continents, typically up to 40% of the maximum flow length. This downstream clustering suggests an optimum distribution of humans in large river basins for trade, transport, and natural resource utilization but with attendant implications …

In terrestrial systems limited by water availability the spatial distribution of vegetation can self‐organize into a mosaic of vegetated patches and bare soil. Spatially extensive competition for water and short‐range facilitation underpin many models that describe the process of vegetation pattern formation. Earlier studies investigating this self‐organized patchiness have largely considered smooth landscapes. However, topographic variations can significantly alter the redistribution of surface water flow and therefore the pattern‐forming process. Here, we consider how microtopographic variations, at the scale of individual plants, alters self‐organized vegetation patterns with the use of a simple ecohydrological model. We show that increasing microtopography can induce a change from banded vegetation, oriented across the slope, to irregular drainage patterns, oriented in the downslope direction. The mechanism …

We investigated the scaling and topology of engineered urban drainage networks (UDNs) in two cities, and further examined UDN evolution over decades. UDN scaling was analyzed using two power law scaling characteristics widely employed for river networks: (1) Hack's law of length ( L )‐area ( A ) [ ] and (2) exceedance probability distribution of upstream contributing area ( δ ) [ ]. For the smallest UDNs (<2 km 2 ), length‐area scales linearly ( h ∼ 1), but power law scaling ( h ∼ 0.6) emerges as the UDNs grow. While plots for river networks are abruptly truncated, those for UDNs display exponential tempering [ ]. The tempering parameter c decreases as the UDNs grow, implying that the distribution evolves in time to resemble those for river networks. However, the power law exponent ɛ for large UDNs tends to be greater than the range reported for river networks. Differences in generative processes and engineering …

Mother Nature has left amazingly regular geomorphic patterns on the Earth's surface. These patterns are often explained as having arisen as a result of some optimal behaviour of natural processes. However, there is little agreement on what is being optimized. As a result, a number of alternatives have been proposed, often with little a priori justification with the argument that successful predictions will lend a posteriori support to the hypothesized optimality principle. Given that maximum entropy production is an optimality principle attempting to predict the microscopic behaviour from a macroscopic characterization, this paper provides a review of similar approaches with the goal of providing a comparison and contrast between them to enable synthesis. While assumptions of optimal behaviour approach a system from a macroscopic viewpoint, process-based formulations attempt to resolve the mechanistic details …

A new algorithm is developed to extract flow paths from digital elevation data without planar dispersion on the basis of the concept of global search. Widely used nondispersive algorithms, such as deterministic eight‐neighbor flow direction retrieval algorithms, suffer serious uncertainty in their determined flow paths because of the lack of variability, i.e., only eight allowed flow directions. Although uncertainty at the local level is an inherent problem residing in the domain discretization, this study shows that more reasonable flow paths at the global scale can be obtained by maximizing the use of all information stored in the given digital elevation data. By utilizing information stored in cells other than those in the direct vicinity, this alternative approach can reduce the uncertainty residing in the extraction of flow paths. The proposed algorithm makes a significant improvement in flow path variability on both theoretical and …

A core problem in monitoring water quality of a river basin is identifying an optimal positioning of a limited number of water-sampling sites. Various optimality criteria have been suggested for this selection process in earlier studies. However, the search for sets of sampling sites that satisfy such criteria poses a challenging optimization problem, especially for a large basin. Here, we show that for particular types of objective functions, the optimization procedure can be dramatically simplified via an analogy with the formulation of Shannon entropy. On this basis, we propose an efficient algorithm that can easily determine the optimal location of water quality sampling sites in a river network. The proposed algorithm can be used standalone or in conjunction with a heuristic optimization algorithm such as a genetic algorithm. For the latter, the proposed algorithm filters only competitive candidates and makes a contribution …

Soil moisture (SM) plays an important role in determining the antecedent condition of a watershed, while topographic attributes define how and where SM and rainfall interact to create floods. Based on this principle, we present a method to identify flood risk at a location in a watershed by using remotely sensed SM and open-access information on rainfall, soil properties, and topography. The method consists of three hydrologic modules that represent the generation, transfer, and accumulation of direct runoff. To simplify the modeling and provide timely warnings, the flood risk is ascertained based on frequency of exceedance, with warnings issued if above a specified threshold. The simplicity of the method is highlighted by the use of only three parameters for each watershed of interest, with effective regionalization allowing use in ungauged watersheds. For this proof-of-concept study, the proposed model was …

We postulate that the spatial variability in flow velocity in a basin, arising from the systematic downstream variation of celerity, may explain the observed nonlinear rainfall‐runoff relationships. This is based on the argument that different rainfall excess rates will produce different velocity fields in a basin due to the nonlinear relation between velocity and flow. In particular, we show that if the mean velocity V varies with flow Q as V ∝ Q m , then the time to peak t p and the peak f ( t p ) of the network instantaneous response function (IRF) vary as t p ∝ i e − m and f ( t p ) ∝ i e + m , where i e is the rainfall excess rate.

The self‐similar tree topology in open dissipative systems is formed as a result of self‐organization and found in various examples, such as river networks, blood vessels, vascular organizations in plants, and even lightning. It is generally assumed that the tree organization is a result of a dynamic process that minimizes the dissipation of energy. Here, we argue that inherent randomness is a sufficient condition for the generation of tree patterns under evolutionary dynamics and the decrease of energy expenditure is not the cause but a consequent signature. © 2008 Wiley Periodicals, Inc. Complexity, 13: 30–37, 2008

This paper presents two related subjects of urban hydrology, i.e., a closed-form reservoir routing equation for peak outflow; and the evaluation of the hydrological risk of an uncontrolled detention basin, where the latter requires the coupling of reservoir routing and a risk assessment method. Here, the hydrological risk is defined as the probability that peak outflow from the detention basin exceeds the target value set for preventing downstream flooding. Among the available risk assessment methods, the mean-value first-order second-moment (MFOSM) and advanced first-order second-moment (AFOSM) methods are known as giving a good balance between accuracy and computational requirements, and are chosen in this study. To facilitate the application of the MFOSM and AFOSM methods, a closed-form equation is derived for reservoir routing. The developed routing model yields an estimate of peak outflow very …

This paper presents improvements to the global D8 (GD8) method for calculating single flow directions in a grid digital elevation model. Flow directions computed from grid digital elevation models serve as the foundation for much of the analysis and modeling of hydrological processes that are driven by topographic gradients. The literature includes both single flow direction methods, where flow goes to only one downslope cell, and multiple flow direction methods that apportion flow among multiple downslope cells. Among single flow direction methods, the standard D8 method, in which the flow direction is set based on the steepest local slope, results in bias on surfaces that do not align with the grid directions. Efforts to address this problem have led to the development of extended methods that account for elevation values further upslope in determining flow directions. We have identified discrepancies in one such …

The choice of a flow path extraction method is a key issue in numerical simulation of fluvial landscape evolution. Most whole landscape evolution models use the deterministic eight-neighbor flow direction retrieval method (D8), which generates angular uncertainty in determined flow paths. In the modeling of landscape evolution, the uncertainty generated at each local flow direction accumulates over both space and time. Recently, a new method which searches for flow paths over global scale, called global D8 or GD8, was proposed as an alternative to D8. GD8 relaxes uncertainty generated at a local level over an entire flow path while still defining specific flow paths without artificial dispersion. On the basis of these advantages of GD8 demonstrated for static landscapes, this paper presents the first landscape evolution model that uses GD8, i.e., a new Landscape Evolution model using Global Search (LEGS …

The downstream hydraulic geometry relationships, i.e., the downstream variation of the water surface width W , the hydraulic depth H , and the mean velocity V at a constant flow frequency, represent the adaptation of channel geometry and flow dynamics to a given hydrological regime. It has been reported that W , H , and V all tend to increase in the downstream direction for most natural rivers but their increasing rates show relative differences. It is widely known that most natural rivers exhibit W increasing at a greater rate compared to H , indicating the formation of wide and shallow rivers. Nevertheless, rivers showing the opposite to this trend, i.e., H increases at a rate greater than that of W , have also been observed. We investigated four rivers in this study where two of them (the Kansas River and the Tennessee River) show greater increasing rate of W than that of H and the other two (the Mississippi River and the …

Water and pollutant fluxes from combined sewer overflows (CSO) have a significant impact on receiving waters. The random nature of rainfall forcing dominates the variability of sewer discharges, pollutant loads, and concentrations. An analytical model developed here shows how sewer network topology and rainfall properties variously impact the stochasticity of CSO functioning. Probability distributions of sewer discharge and concentration compare well with the results from a calibrated Storm Water Management Model in an application to a sewershed located in Dresden, Germany. The model is determined by only four parameters, three of which can be predicted a priori, two from the rainfall record and one from the network topology using geomorphological flow recession theory, while the fourth can be estimated from a short discharge time series. The sensitivity of CSO and wastewater treatment loads to network …

Self-similar topology, which can be characterized as power law size distribution, has been found in diverse tree networks ranging from river networks to taxonomic trees. In this study, we find that the statistical self-similar topology is an inevitable consequence of any full binary tree organization. We show this by coding a binary tree as a unique bifurcation string. This coding scheme allows us to investigate trees over the realm from deterministic to entirely random trees. To obtain partial random trees, partial random perturbation is added to the deterministic trees by an operator similar to that used in genetic algorithms. Our analysis shows that the hierarchical density of binary trees is more diverse than has been described in earlier studies. We find that the connectivity structure of river networks is far from strict self-similar trees. On the other hand, organization of some social networks is close to deterministic supercritical …

Natural river networks exhibit regular scaling laws in their topological organization. Here, we investigate whether these scaling laws are unique characteristics of river networks or can be applicable to general binary tree networks. We generate numerous binary trees, ranging from purely ordered trees to completely random trees. For each generated binary tree, we analyze whether the tree exhibits any scaling property found in river networks, i.e., the power-laws in the size distribution, the length distribution, the distance-load relationship, and the power spectrum of width function. We found that partially random trees generated on the basis of two distinct types of deterministic trees, i.e., deterministic critical and supercritical trees, show contrasting characteristics. Partially random trees generated on the basis of deterministic critical trees exhibit all power-law characteristics investigated in this study with their fitted …

Horton’s laws have long served as fundamental principles for fractal organization of a drainage basin. Scaling ratios of stream number, length, area, and side tributary have been proposed but the definitions of these basic variables are inconsistent. The concept of eigenarea can be utilized to resolve this issue. Here, we investigated the relationships among Hortonian scaling ratios using the concept of eigenarea. We found that the eigenarea ratio, likewise other scaling ratios, is invariant within a stream network, the law of eigenarea. We analytically revealed that the eigenarea ratio is equivalent to the stream length ratio. Our examination implies that Horton’s original two ratios of stream number and length can represent most Hortonian scaling ratios except Tokunaga ratio.

Use of a harmony search for optimal design of Coffer Dam drainage pipes - the UWA Profiles and Research Repository Skip to main navigation Skip to search Skip to main content the UWA Profiles and Research Repository Home the UWA Profiles and Research Repository Logo Login Home Profiles Organisations Research output Grants Datasets Prizes / Awards Engagement / Activities Press/Media Units Equipment Impacts Search by expertise, name or affiliation Use of a harmony search for optimal design of Coffer Dam drainage pipes Kyungrock Paik, JH Jeong, JH Kim Research output: Contribution to journal › Article › peer-review 11 Citations (Scopus) Overview Original language English Pages (from-to) 119-128 Journal KSCE Journal of Civil Engineering Volume 21 Issue number 2B Publication status Published - 2001 UN SDGs This output contributes to the following UN Sustainable Development Goals (…

Riverscape Dynamics Laboratory

교수님 소개

백경록

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Estimation of catchment-scale evapotranspiration with the simple method based on the maximum entropy production principle

Canopy box framework to represent the surface energy partitioning over vegetated areas

Equilibrium states of humid catchments satisfying both energy and mass conservations

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

백경록

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Estimation of catchment-scale evapotranspiration with the simple method based on the maximum entropy production principle

Canopy box framework to represent the surface energy partitioning over vegetated areas

Equilibrium states of humid catchments satisfying both energy and mass conservations

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집