scholarly journals Riparian trees as common denominators across the river flow spectrum: are ecophysiological methods useful tools in environmental flow assessments?

Water SA ◽  
2014 ◽  
Vol 40 (2) ◽  
pp. 287 ◽  
Author(s):  
K Schachtschneider ◽  
K Reinecke
Keyword(s):  
River Flow ◽  
Environmental Flow ◽  
Riparian Trees

scholarly journals Determination of the Environmental Flow Using the Modern Optimization Methods for Release Flow based on Game Theory

2021 ◽  
Author(s):  
Amir Foroughian ◽  
Ehsan Derikvand ◽  
Hossein Eslami ◽  
Saeb Khoshnavaz
Keyword(s):  
Water Quality ◽  
Game Theory ◽  
River Flow ◽  
Optimization Methods ◽  
Environmental Flow ◽  
Quality Parameters ◽  
Base Flow ◽  
Water Release ◽  
Qualitative And Quantitative ◽  
Good Potential

Abstract To prevent environmental risks and preserve water quality, it is necessary to determine the environmental flow of rivers. Water release from reservoirs can be used to determine the environmental flow and water quality at the downstream of a dam. In this study, considering the quantitative and qualitative objectives, water release from Dez dam was suggested as a way for preserving the environment of river. To identify the optimal release flow of Dam, an environmental zone was determined using the hydrological methods of Tennant and aquatic base flow. The Qual-2k model was used to simulate 6 quality parameters in River. The results proved its good potential for simulation of the studied quality parameters including BOD. The optimal river flow was determined by Game theory, and different qualitative and quantitative scenarios were studied using the Nash multiplying function. The results showed, with increases in qualitative and quantitative objectives of the problem, the optimal release flows are decreased and increased, respectively.

scholarly journals Environmental Flow Assessment of a Tropical River System Using Hydrological Index Methods

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2477
Author(s):  
Mohammad Haroon Hairan ◽  
Nor Rohaizah Jamil ◽  
Mohammad Noor Amal Azmai ◽  
Ley Juen Looi ◽  
Moriken Camara
Keyword(s):  
River Flow ◽  
Maximum Flow ◽  
River System ◽  
Environmental Flow ◽  
Low Flow ◽  
Index Method ◽  
Flood Pulses ◽  
Post Impact ◽  
High Flood ◽  
High Level

Tropical rivers and wetlands are recognized as one of the greatest and most abundant ecosystems in terms of ecological and social benefits. However, climate change, damming, overfishing, water pollution, and the introduction of exotic species threaten these ecosystems, which puts about 65% of river flow and aquatic ecosystems under a moderate to high level of threat. This paper aims to assess the environmental flow of the Selangor River based on the hydrological index method using the Global Environmental Flow Calculator (GEFC) and Indicators of Hydrological Alterations (IHA) software. The daily flow data collected by the Department of Irrigation and Drainage (DID), Malaysia, over a 60-year period (1960–2020) was used in this study to assess the Selangor River flow alterations. As per the results, the river flow has had two distinct periods over the last 60 years. In the first period, the river flows without any alteration and has a natural flow with high flood pulses and low flow pulses. While in the second, or post-impact, period, the flow of the river has a steady condition throughout the year with very little fluctuations between the dry and wet seasons of the year. From the overall comparison of the pre- and post-impact periods, it can be concluded that the minimum flow in the dry seasons of the year has increased, while the maximum flow has decreased in the monsoon seasons during the post-impact period. As a result, the Flow Duration Curve (FDC) and Environmental Management Class (EMC) analysis of the river flow recommends that the Selangor River be managed under EMC “C” to provide sufficient water for both human use and ecosystem conservation, which would also help to avoid a water level drop in the reservoirs. However, further holistic studies are suggested for a detailed analysis of the effects of the dams on aquatic biodiversity and ecosystem services in the Selangor River Basin.

Environmental flow requirements and impacts of climate change-induced river flow changes on ecology of the Indus Delta, Pakistan

2016 ◽  
Vol 7 ◽  
pp. 185-195 ◽  
Author(s):  
Kashif Majeed Salik ◽  
Muhammad Zia-ur-Rahman Hashmi ◽  
Sadia Ishfaq ◽  
Waheed-ul-Zafar Zahdi
Keyword(s):  
Climate Change ◽  
River Flow ◽  
Environmental Flow ◽  
Indus Delta ◽  
Flow Changes ◽  
Impacts Of Climate Change

scholarly journals Assessment of hydrological alteration and environmental flow requirements for Srisailam dam on Krishna River, India

Water Policy ◽  
2018 ◽  
Vol 20 (6) ◽  
pp. 1176-1190 ◽  
Author(s):  
A. Uday Kumar ◽  
K. V. Jayakumar
Keyword(s):  
River Flow ◽  
Environmental Flow ◽  
Vital Role ◽  
Low Risk ◽  
Mean Flow ◽  
Discharge Data ◽  
Hydrological Alteration ◽  
Seasonal Flow ◽  
Biotic Diversity ◽  
Medium Risk

Abstract Natural flow plays a vital role in forming biotic diversity by controlling essential environmental conditions within the river channel and floodplain. This paper assesses the changes in streamflow and ecology caused on Krishna River by Srisailam dam. Regulated and unregulated river flow discharge data were collected at Nagarjuna Sagar gauge station which is located downstream of Srisailam dam. Flow Health (FH) software developed by the International Water Centre, Brisbane is used to calculate the hydrological alteration and environmental flow requirements due to Srisailam dam. Results show that impoundment of the dam mainly decreases the high flows by storing flood flow for water supply, irrigation purposes, etc., and enhances low flows due to hydropower operation. Regulation of the dam significantly affected the mean flow in August, September, and October. Mean annual flow (MAF) decreased considerably and seasonal flow shifted. The minimum flow released from the dam to downstream was calculated by two options, namely, low risk and medium risk to the environment. Low risk achieved a score of 0.61 FH and 0.5 FH was achieved by high risk, with a MAF volume of 40% (i.e., 7,225 m3) and 30% (5,847 m3), respectively.

scholarly journals Conserving Rivers and Their Biodiversity in Tanzania

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2612 ◽  
Author(s):  
Nadia A. Seeteram ◽  
Pendo T. Hyera ◽  
Lulu T. Kaaya ◽  
Makarius C. S. Lalika ◽  
Elizabeth P. Anderson
Keyword(s):  
Water Policy ◽  
Human Population ◽  
River Flow ◽  
Current Knowledge ◽  
Water Security ◽  
Environmental Flow ◽  
United Republic ◽  
United Republic Of Tanzania ◽  
River Conservation ◽  
National Water

The United Republic of Tanzania (Tanzania) is rich in freshwater resources and biodiversity. In this article, we highlight the importance of Tanzanian rivers and make a case for the conservation of the freshwater and terrestrial species that rely on these rivers. We provide an overview of current knowledge on Tanzanian rivers and discuss progress towards implementation of the National Water Policy (2002) and Water Management Act (2009), two legislative instruments that have motivated environmental flow assessments on at least six major rivers and offer legal backing for river conservation. We examine major challenges that pose significant threats to water security for river ecosystems and humans in Tanzania, among those: (1) human population growth, (2) agricultural expansion, (3) river flow alterations, (4) industrialization, (5) introduced species, and (6) climate change. We conclude by offering recommendations for future river conservation efforts in Tanzania.

scholarly journals River Flow Alterations Caused by Intense Anthropogenic Uses and Future Climate Variability Implications in the Balkans

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 7
Author(s):  
Christina Papadaki ◽  
Elias Dimitriou
Keyword(s):  
Climate Variability ◽  
Climate Models ◽  
River Flow ◽  
Hydrological Model ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Environmental Flow ◽  
The Balkans ◽  
Global Circulation Models ◽  
Sustainable Water Resources Management

River flow alterations, caused by climate variability/change and intense anthropogenic uses (e.g., flow regulation by dams) are considered among the main global challenges of which hydrologists should be dealing with. For the purpose of this study, environmental flow and potential hydrological alterations are made for the extended Drin river basin, with limited historical hydrological information available. To overcome this limitation environmental flow assessment is made using simulated streamflow data from a watershed hydrological model. Descriptive statistics applied to streamflow values indicate that median monthly flows with no anthropogenic uses are consistently greater than those with anthropogenic uses by 0–37.4 m3/s in all subbasins. Moreover, an investigation of potential climate variability/change impact on river flow regime is made using streamflow simulations from a global hydrological model. Results indicate that hydrologic alteration is intense between nonregulated and regulated streamflow conditions. More specifically, for all Global Circulation Models and Regional Climate Models combinations, and both regulated and unregulated streamflow conditions, the minimum discharge values had statistically significant decreasing trends, except one combination (RCP 4.5–RCA4/ECEARTH) for unregulated conditions. Finally, results from this preliminary analysis could enhance the necessary conversations among all relevant stakeholders to discuss and decide on sustainable water resources management issues for the development of a Drin Basin Management Plan in the future.

scholarly journals Environmental flow assessments in estuaries related to preference of phytoplankton

2014 ◽  
Vol 18 (5) ◽  
pp. 1785-1791 ◽  
Author(s):  
Z. F. Yang ◽  
T. Sun ◽  
R. Zhao
Keyword(s):  
Environmental Factors ◽  
River Flow ◽  
Yellow River ◽  
Environmental Flows ◽  
River Estuary ◽  
High Amplitude ◽  
Environmental Flow ◽  
Negative Effects ◽  
Flood Pulses ◽  
Complex Relationships

Abstract. An approach to assess estuarine environmental flow based on phytoplankton preference, including the complex relationships between hydrological modifications and ecosystem biomass, was developed in this study. We initially established a relationship between biomass requirements for primary and higher nutritional level organisms based on the ecosystem nutritional energy flow principles. Subsequently, diagnostic pigments were employed to represent phytoplankton community biomass, which indicated competition between two groups of phytoplankton in the biochemistry process. Considering empirical relationships between diagnostic pigments and critical environmental factors, biomass responses to river discharge were established by simulating distributions of critical environmental factors under action of river discharges and tide currents. Consequently, environmental flows were recommended for different fish biomass requirements. We used the Yellow River estuary as a case study; and May and June were identified as critical months for maintaining environmental flow. Temporal variation in natural river flow dynamics, which was used as a proxy for environmental flow, should be carefully examined in artificial hydrological regulation strategies, particularly during high-amplitude flood pulses, which might result in negative effects on phytoplankton groups, and subsequently higher aquatic species biomass.

scholarly journals Widespread dieback of riparian trees on a dammed ephemeral river and evidence of local mitigation by tributary flows

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2622 ◽  
Author(s):  
Caitlin M. S. Douglas ◽  
Mark Mulligan ◽  
Xavier A. Harrison ◽  
Joh R. Henschel ◽  
Nathalie Pettorelli ◽  
...  
Keyword(s):  
Channel Flow ◽  
River Flow ◽  
Main Channel ◽  
Riparian Trees ◽  
Ephemeral Rivers ◽  
Riparian Tree ◽  
Tree Dieback ◽  
Anthropogenic Threats ◽  
Individual Trees ◽  
Key Resources

Ephemeral rivers act as linear oases in drylands providing key resources to people and wildlife. However, not much is known about these rivers’ sensitivities to human activities. We investigated the landscape-level determinants of riparian tree dieback along the Swakop River, a dammed ephemeral river in Namibia, focusing on the native ana tree (Faidherbia albida) and the invasive mesquite (Prosopisspp.). We surveyed over 1,900 individual trees distributed across 24 sites along a 250 km stretch of the river. General linear mixed models were used to test five hypotheses relating to three anthropogenic threats: river flow disruption from damming, human settlement and invasive species. We found widespread dieback in both tree populations: 51% mortality in ana tree, with surviving trees exhibiting 18% canopy death (median); and 26% mortality in mesquite, with surviving trees exhibiting 10% canopy death. Dieback in the ana tree was most severe where trees grew on drier stretches of the river, where tributary flow was absent and where mesquite grew more abundantly. Dieback in the mesquite, a more drought-tolerant taxon, did not show any such patterns. Our findings suggest that dieback in the ana tree is primarily driven by changes in river flow resulting from upstream dam creation and that tributary flows provide a local buffer against this loss of main channel flow. The hypothesis that the invasive mesquite may contribute to ana tree dieback was also supported. Our findings suggest that large dams along the main channels of ephemeral rivers have the ability to cause widespread mortality in downstream riparian trees. To mitigate such impacts, management might focus on the maintenance of natural tributary flows to buffer local tree populations from the disruption to main channel flow.

Sign in / Sign up

Export Citation Format

Share Document