Delineating small karst watersheds based on digital elevation model and  eco-hydrogeological principles

Luo, Guang Jie; Wang, Xinbo; Bai, Xiaoyong; Liu, Xiu Ming; Cheng, An Yun

doi:10.5194/se-7-457-2016

Cited by 14 publications

(6 citation statements)

References 50 publications

(38 reference statements)

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“…In natural landscapes, remotely sensed data have been successfully employed to generate gridded digital elevation models (DEMs), which are used in geographical information systems (GIS) for drainage network extraction, determination of flow direction and accumulation, and watershed delineation (Luo, Wang, Bai, Liu, & Cheng, 2016;Wechsler, 2007). These systems use algorithms such as the D8 flow direction (O'Callaghan & Mark, 1984), which assumes that flow direction always originates at the centre of each DEM pixel and travels downslope, following the steepest gradient towards one of the eight nearest pixel neighbours until the watershed outlet is reached (Freeman, 1991).…”

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confidence: 99%

Determination of subcatchment and watershed boundaries in a complex and highly urbanized landscape

Kayembe

Mitchell

2018

Hydrological Processes

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Urban development significantly alters the landscape by introducing widespread impervious surfaces, which quickly convey surface run‐off to streams via stormwater sewer networks, resulting in “flashy” hydrological responses. Here, we present the inadequacies of using raster‐based digital elevation models and flow‐direction algorithms to delineate large and highly urbanized watersheds and propose an alternative approach that accounts for the influence of anthropogenically modified land cover. We use a semi‐automated approach that incorporates conventional drainage networks into overland flow paths and define the maximal run‐off contributing area. In this approach, stormwater pipes are clustered according to their slope attributes, which define flow direction. Land areas drained by each cluster and contributing (or exporting) flow to a topographically delineated catchment were determined. These land masses were subsequently added or removed from the catchment, modifying both the shape and the size. Our results in a highly urbanized Toronto, Canada, area watershed indicate a moderate net increase in the directly connected watershed area by 3% relative to a topographically forced method; however, differences across three smaller scale subcatchments are greater. Compared to topographic delineation, the directly connected watershed areas of both the upper and middle subcatchments decrease by 5% and 8%, respectively, whereas the lower subcatchment area increases by 15%. This is directly related to subsurface storm sewer pipes that cross topographic boundaries. When directly connected subcatchment area is plotted against total streamflow and flashiness indices using this method, the coefficients of variation are greater (0.93 to 0.97) compared to the use of digital elevation model‐derived subcatchment areas (0.78 to 0.85). The accurate identification of watershed and subcatchment boundaries should incorporate ancillary data such as stormwater sewer networks and retention basin drainage areas to reduce water budget errors in urban systems.

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confidence: 99%

Determination of subcatchment and watershed boundaries in a complex and highly urbanized landscape

Kayembe

Mitchell

2018

Hydrological Processes

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“…The presence of exposed rock can alter the hydrodynamic properties of slope flows, thereby delaying the arrival time of runoff in the channel (Zegers et al, 2021). The lithology and hydrogeological structures in karst regions are unique and complex, with typical binary underground hydrogeological structures (Luo et al, 2016). Therefore, studying the influence of KCF on hydrologic processes is crucial in exploring the law of hydrological phenomena and water resources management.…”

Section: Introductionmentioning

confidence: 99%

Mediation effects of vegetation, land use and cover change and karst characteristics on hydrologic processes in heterogeneous karst basins

Wu,

Li,

Xiao

et al. 2024

Hydrological Processes

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A thorough understanding of the complex response of hydrologic processes to latent factors is of great significance for regional soil erosion and water resources management. However, what kind of mediation effect exists between hydrologic processes and latent factors is not yet clear, especially in heterogeneous karst regions. In this study, the elasticity coefficient method and partial least squares structural equation modelling (PLS‐SEM) were used to investigate the mechanism of latent factors on hydrologic processes in karst basins and to explore the mediation effect between latent factors and hydrologic processes. The results show that the runoff of Yeji River Basin decreased during 1997–2004, but increased or stabilized since 2005. On the monthly scale, the runoff in July and December showed an ‘inverted V‐shaped’ change. Both elasticity coefficient method and PLS‐SEM showed that climate change contributed the most to runoff (direct effect accounted for 37.94% ~ 61.41%). In PLS‐SEM, the total effect sizes of latent factors on runoff were as follows: climate change (0.751 ~ 0.963) > vegetation (0.296 ~ 0.740) > karst characteristics factors (KCF) (−0.454 ~ −0.563) > human activities (−0.036 ~ −0.528) > land use and cover change (LUCC) (−0.036 ~ −0.205). In the typical karst basin, two mediation pathways have been determined: human activities‐vegetation/LUCC‐runoff, where vegetation and LUCC had a mediation effect of relationships between human activities and runoff; climate change‐KCF‐runoff, where KCF had a mediation effect of relationships between climate change and runoff. Moreover, PLS‐SEM is a preferred method to decouple the complex responses of hydrologic processes in heterogeneous karst basins to climate change and human activities than the elasticity coefficient method. This study conducted further research and exploration on the mechanism of hydrologic processes in heterogeneous karst basins, and provided valuable theoretical references for grassroots water managers to cope with water resources management under the context of future climate change.

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“…Hydrologists have recently focused on the inter-annual and multi-decadal periodicities of the largest rivers in the world through mouth-to-ocean discharge estimations, and their relationship with global climate indices was explored along with the relationship of multitemporal scales of runoff changes and meteorological elements of basins [31,32]. Karst watersheds are characterized by thin surface soil, high infiltration capacity, and complex topography due to the special geologic condition and thus generally are distinct from nonkarst watersheds [33][34][35]. However, there is a lack of attention to the multi-scale coupling study of extreme climate events and ecological hydrological processes at the watershed scale.…”

Section: Introductionmentioning

confidence: 99%

Response of Runoff Change to Extreme Climate Evolution in a Typical Watershed of Karst Trough Valley, SW China

Chen

Yang

et al. 2023

Atmosphere

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Identifying the response of runoff changes to extreme climate evolution was of great scientific significance for the rational regulation of watershed water resources and the prevention of hydrological disasters. However, the time–frequency response relationships were not clear. The Yinjiang River watershed, a typical watershed with karst trough valley areas, was chosen to identify the impact of different climatic driving factors on runoff changes from 1984 to 2015. Continuous wavelet transform (CWT), cross-wavelet transform (XWT), and wavelet coherence transform (WTC) were performed to study the response relationship and time–frequency effect between runoff changes and extreme climate change at different time scales. The main results showed that: (1) Twelve extreme climate indices (ECIs) were detected to have a significant impact on runoff changes, mainly on a 6-year time scale; (2) The R10 and Rx1day in extreme precipitation index and SU34.4 and TNx in the extreme temperature index were the main driving factors of runoff changes, which had relatively large impacts on runoff changes in high and low energy vibration regions. However, the remaining eight ECIs that passed the 0.05 confidence level showed relatively large impacts on runoff changes only in low energy vibration regions; (3) The transition of the interaction between ECIs and runoff changes in high and low time–frequency scales was related to the abrupt change characteristics of the ECIs. The correlation of abrupt change was an important reason for the emergence of highly correlated regions that trigger high and low energy vibrations; (4) As a whole, the extreme precipitation events were ahead of runoff changes at the high time–frequency scale and exhibited small lag effects at the low time–frequency scale, while extreme temperature events were mainly ahead of runoff changes. This study has effectively revealed the impact of climate factors at different scales on runoff changes, and provides a theoretical understanding for regulating and managing water resources in karst basins.

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Delineating small karst watersheds based on digital elevation model and eco-hydrogeological principles

Cited by 14 publications

References 50 publications

Determination of subcatchment and watershed boundaries in a complex and highly urbanized landscape

Determination of subcatchment and watershed boundaries in a complex and highly urbanized landscape

Mediation effects of vegetation, land use and cover change and karst characteristics on hydrologic processes in heterogeneous karst basins

Response of Runoff Change to Extreme Climate Evolution in a Typical Watershed of Karst Trough Valley, SW China

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