The Sanaga discharge at the Edea Catchment outlet (Cameroon): An example of hydrologic responses of a tropical rain-fed river system to changes in precipitation and groundwater inputs and to flow regulation

2010 ◽  
Vol 27 (6) ◽  
pp. 754-771 ◽  
Author(s):  
Jean-Guy Dzana ◽  
Jules Remy Ndam Ngoupayou ◽  
Paul Tchawa
Keyword(s):  
River System ◽  
Flow Regulation ◽  
Hydrologic Responses

Temporal variation of larval fish assemblages of the Murray Mouth in prolonged drought conditions

2013 ◽  
Vol 64 (10) ◽  
pp. 932 ◽  
Author(s):  
L. B. Bucater ◽  
J. P. Livore ◽  
C. J. Noell ◽  
Q. Ye
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
River System ◽  
Sampling Period ◽  
Marine Species ◽  
Flow Regulation ◽  
Nursery Areas ◽  
Transition Zones ◽  
Murray Darling Basin ◽  
Drought Conditions

Estuaries are transition zones that link freshwater and marine ecosystems and are often used as nursery areas by fish. The Murray–Darling Basin, which is heavily affected by flow regulation and water extraction, is the largest river system in Australia and terminates at the Murray Mouth estuary. Protracted drought conditions resulted in extremely low flows to the Murray Mouth that affected water condition, fish abundance, community structure and fish use of the estuary (e.g. nursery areas). The aims of the present study were to examine temporal changes in larval fish assemblages in this estuary. The assemblages were dominated by two gobiid species, Arenigobius bifrenatus and Tasmanogobius lasti. There was a noticeable absence or low abundance of freshwater, diadramous and large-bodied marine species that use this estuary for reproductive functions. Monthly differences in larval fish assemblages, between August–September and October–November, were attributed to increases in the abundances of A. bifrenatus in October and November and oscillation in T. lasti during the entire sampling period. The outcomes of the present study suggested that larval fish assemblages in drought conditions are limited to small-bodied species tolerant of high salinities and that freshwater flows are needed for the estuary to function as a nursery for other species.

scholarly journals Fish assemblage patterns across a gradient of flow regulation in an Australian dryland river system

2011 ◽  
Vol 27 (2) ◽  
pp. 168-183 ◽  
Author(s):  
S. R. Balcombe ◽  
A. H. Arthington ◽  
M. C. Thoms ◽  
G. G. Wilson
Keyword(s):  
Fish Assemblage ◽  
River System ◽  
Flow Regulation ◽  
Dryland River

Impact assessment of structural barriers and flow regulation on the Ganga River morphology and ecology

2021 ◽  
Author(s):  
Gaurav Kailash Sonkar ◽  
Kumar Gaurav
Keyword(s):  
Ecological Impact ◽  
River System ◽  
Flow Regulation ◽  
Ganga River ◽  
Structural Barriers ◽  
Lateral Connectivity ◽  
Discharge Data ◽  
Minimum Flow ◽  
Farakka Barrage ◽  
Dolphin Population

<p>The Ganga-Brahmaputra river system in the Himalayan Foreland supports diverse aquatic fauna. Decades of flow regulation through dams and barrages have affected their habitat suitability. To evaluate the impacts of large barrages on the morphology and habitat ecology we studied two different reaches (middle and lower) of the Ganga River. These reaches are the habitat of the endangered Ganga River dolphin (<em>Platanista gangetica</em>). In a reach in the middle Ganga between Bijnor and Narora barrage, a reported rise in dolphin population has been documented. In contrast, near the Farakka barrage in the lower reach of the Ganga River, a significant decline in the dolphin population has been observed.</p><p>We use Corona and time-series Landsat satellite images along with flow discharge data to assess the morphological and ecological impact of the barrages. In middle Ganga, the dolphin habitat is isolated between the Bijnor and Narora barrage where the minimum flow is available throughout the year for the dolphins to thrive.  On the other hand, in the lower Ganga, contrasting impacts are observed in the proximity (upstream/downstream) of the Farakka barrage. In the downstream, reduction in water (by one-third in the pre-monsoon discharge) and sediment discharge has decoupled the channel belt to its floodplain resulting in a loss of lateral connectivity. The presence of minimum flow between the Bijnor and Narora barrage has aided the dolphin population rise while the loss of lateral connectivity and excess siltation at the Farakka barrage has made the river reach unsuitable for habitation.   </p>

Managing Salinity in the Upper Santa Clara River System of California

2009 ◽  
Author(s):  
Nathan Brown ◽  
Brian Louie ◽  
Frank Guerrero ◽  
Terry Foreman ◽  
Sorab Panday ◽  
...  
Keyword(s):  
River System

Establishing an empirical equation for the relationship between total suspended solids and total phosphorus concentrations in the downstream Red river water

2020 ◽  
Vol 20 (3) ◽  
pp. 325-332
Author(s):  
Le Nhu Da ◽  
Le Thi Phuong Quynh ◽  
Phung Thi Xuan Binh ◽  
Duong Thi Thuy ◽  
Trinh Hoai Thu ◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Suspended Solids ◽  
Empirical Relationship ◽  
Water Environment ◽  
Total Suspended Solids ◽  
River System ◽  
Red River ◽  
Reservoir Impoundment ◽  
Downstream Section ◽  
Reasonable Prediction

Recently, the Asian rivers have faced the strong reduction of riverine total suspended solids (TSS) flux due to numerous dam/reservoir impoundment. The Red river system is a typical example of the Southeast Asian rivers that has been strongly impacted by reservoir impoundment in both China and Vietnam, especially in the recent period. It is known that the reduction in total suspended solids may lead to the decrease of some associated elements, including nutrients (N, P, Si) which may affect coastal ecosystems. In this paper, we establish the empirical relationship between total suspended solids and total phosphorus concentrations in water environment of the Red river in its downstream section from Hanoi city to the Ba Lat estuary based on the sampling campaigns conducted in the dry and wet seasons in 2017, 2018 and 2019. The results show a clear relationship with significant coefficient between total suspended solids and total phosphorus in the downstream Red river. It is expressed by a simple equation y = 0.0226x0.3867 where x and y stand for total suspended solids and total phosphorus concentrations (mg/l) respectively with the r2 value of 0.757. This equation enables a reasonable prediction of total phosphorus concentrations of the downstream Red river when the observed data of total suspended solids concentrations are available. Thus, this work opens up the way for further studies on the calculation of the total phosphorus over longer timescales using daily available total suspended solids values.

Basic principles for assessing the safety of fish products from the ponds exposed to the influence of nuclear fuel cycle enterprises

2019 ◽  
pp. 106-114
Author(s):  
A. V. Trapeznikov ◽  
V. N. Trapeznikova ◽  
A. V. Korzhavin ◽  
V. N. Nikolkin ◽  
A. P. Plataev
Keyword(s):  
Fuel Cycle ◽  
Specific Activity ◽  
River System ◽  
Food Product ◽  
Human Consumption ◽  
Basic Principles ◽  
Fish Products ◽  
Permissible Levels ◽  
Irtysh River

Relevance. In connection with the development of nuclear energy, many aquatic ecosystems have been exposed to radioactive substances. Fish, as an element of biota, is capable to accumulate radionuclides. However, fish is a traditional food. The control of the technogenic radionuclides accumulation level in the ichthyofauna is an important link in ensuring human security.Intention. To analyze the long-term data on the content of long-lived technogenic radionuclides 90Sr and 137Cs in the ichthyofauna of the Ob-Irtysh river system for the period from 2004 to 2016 and Beloyarsky pond for the period from 1977 to 2018.Methodology. Fish as a food product was assessed according to two criteria: a) permissible levels of specific activity of radionuclides (SanPiN 2.3.2.1078-01); b) using the indicator of conformity B and the uncertainty of its definition В (GOST 32161-2013 and GOST 32163-2013).Results and Discussion. Fish of all species that live in the river Tetcha, is not suitable for food use according to the criteria of SanPiN 2.3.2.1078-01, GOST 32161-2013 and GOST 32163-2013. The fish of the Ob-Irtysh river system, the habitat of which is located outside the Tetcha, meets the requirements for fish products. In the period from 1977 to 1989 in the Beloyarsk pond the accumulations of technogenic radionuclides in fish in quantities exceeding sanitary and hygienic standards were possible. Currently, the fish of the Beloyarsky pond fully complies with the sanitary and hygienic requirements for the radiation factor and is safe for human consumption.Conclusion. In the ponds exposed to the atomic energy enterprises, it is necessary to continuously monitor the content of long-lived technogenic radionuclides in fish and assess their amount in accordance with the requirements of SanPiN 2.3.2.1078-01 and using the conformity indicator В and the uncertainty of its determination В. 

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