Patterning Zooplankton Communities in Accordance with Annual Climatic Conditions in a Regulated River System (Nakdong River, South Korea)

Flow regulation is one of the most common anthropogenic factors affecting rivers worldwide. In Korea, 16 weirs were constructed along four major rivers from 2009 to 2012. This study aimed to elucidate initial changes in physical, chemical, and biological variables after the construction of consecutive weirs on the Nakdong River, a major large river system. Water quality variables and phytoplankton cell densities were investigated at eight representative sites and compared with the data recorded before the weir construction. There were spatial and temporal changes in the hydraulic retention time (HRT), total phosphorus (TP), and chlorophyll a concentrations among the eight weir sections. HRT increased after the weir construction, while TP and chlorophyll a tended to decrease from the middle to lower section of the Nakdong River. Furthermore, differences were observed in the phytoplankton community composition between 2006–2007 and 2013. There was a marginal decrease in the duration of centric diatom (Stephanodiscus hantzschii) blooms after weir construction. However, Microcystis aeruginosa proliferated more extensively during summer and autumn than it did before the weir construction. Our results suggest that changes in hydrological factors, in response to consecutive weir construction, may contribute to greater physical, chemical, and ecological variability.

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Resolving conflicts over trans-boundary rivers using bankruptcy methods

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-10-13855-2013 ◽

2013 ◽

Vol 10 (11) ◽

pp. 13855-13887 ◽

Cited By ~ 7

Author(s):

M. Zarezadeh ◽

K. Madani ◽

S. Morid

Keyword(s):

Temporal Distribution ◽

Stability Index ◽

River System ◽

Planning Horizon ◽

Climatic Conditions ◽

Index Method ◽

Allocation Rules ◽

Available Water ◽

Time Sensitivity ◽

Solution Methods

Abstract. A bankruptcy approach is proposed for resolving trans-boundary rivers conflicts in which the total water demand or claim of the riparian parties is more than the available water. Bankruptcy solution methods can allocate the available water to the conflicting parties with respect to their claims. Four bankruptcy rules are used here to allocate the available water to the riparian parties. Given the non-uniform spatial and temporal distribution of water across river basins, bankruptcy optimization models are proposed to allocate water based on these rules with respect to time sensitivity of water deliveries during the planning horizon. Once allocation solutions are developed, their acceptability and stability must be evaluated. Thus, a new stability index method is developed for evaluating the acceptability of bankruptcy solutions. To show how the bankruptcy framework can be helpful in practice, the suggested methods are applied to a real-world tarns-boundary river system with eight riparians under various hydrologic regimes. Stability analysis based on the proposed stability index method suggests that the acceptability of allocation rules is sensitive to hydrologic conditions and demand values. This finding has an important policy implication suggesting that fixed allocation rules and trans-boundary treaties may not be reliable for securing cooperation over trans-boundary water resources as they are vulnerable to changing socio-economic and climatic conditions as well as hydrologic non-stationarity.

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