Paleoenvironmental implications and drainage adjustment in the middle reaches of the Sabarmati river, Gujarat: Implications towards hydrological variability

2017 ◽  
Vol 454 ◽  
pp. 1-14 ◽  
Author(s):  
Sarda Thokchom ◽  
Falguni Bhattacharya ◽  
A. Durga Prasad ◽  
N.N. Dogra ◽  
B.K. Rastogi
Keyword(s):  
Hydrological Variability ◽  
Sabarmati River

Hydrological variability and long-term floristic-structural modifications in different habitats of a tropical semi-deciduous forest

2021 ◽  
Author(s):  
Alisson Borges Miranda Santos ◽  
Vinicius Andrade Maia ◽  
Cléber Rodrigo de Souza ◽  
Natália de Aguiar-Campos ◽  
Aurélio de Jesus Rodrigues Pais ◽  
...  
Keyword(s):  
Deciduous Forest ◽  
Structural Modifications ◽  
Hydrological Variability

scholarly journals Long-term monitoring programme of the hydrological variability in the Mediterranean Sea: a first overview of the HYDROCHANGES network

Ocean Science ◽  
2013 ◽  
Vol 9 (2) ◽  
pp. 301-324 ◽  
Author(s):  
K. Schroeder ◽  
C. Millot ◽  
L. Bengara ◽  
S. Ben Ismail ◽  
M. Bensi ◽  
...  
Keyword(s):  
Time Series ◽  
Mediterranean Sea ◽  
Sampling Interval ◽  
Global Changes ◽  
Hydrological Variability ◽  
Long Term Monitoring ◽  
The Mediterranean ◽  
Set Up ◽  
Term Monitoring

Abstract. The long-term monitoring of basic hydrological parameters (temperature and salinity), collected as time series with adequate temporal resolution (i.e. with a sampling interval allowing the resolution of all important timescales) in key places of the Mediterranean Sea (straits and channels, zones of dense water formation, deep parts of the basins), constitute a priority in the context of global changes. This led CIESM (The Mediterranean Science Commission) to support, since 2002, the HYDROCHANGES programme (http//www.ciesm.org/marine/programs/hydrochanges.htm), a network of autonomous conductivity, temperature, and depth (CTD) sensors, deployed on mainly short and easily manageable subsurface moorings, within the core of a certain water mass. The HYDROCHANGES strategy is twofold and develops on different scales. To get information about long-term changes of hydrological characteristics, long time series are needed. But before these series are long enough they allow the detection of links between them at shorter timescales that may provide extremely valuable information about the functioning of the Mediterranean Sea. The aim of this paper is to present the history of the programme and the current set-up of the network (monitored sites, involved groups) as well as to provide for the first time an overview of all the time series collected under the HYDROCHANGES umbrella, discussing the results obtained thanks to the programme.

Water and sanitation in Africa: current status, trends, challenges and opportunities

2017 ◽  
Author(s):  
George Kararach ◽  
Tito Yepes
Keyword(s):  
Economic Growth ◽  
Rural Poverty ◽  
Water Security ◽  
River Basins ◽  
Current Status ◽  
Institution Building ◽  
Infrastructure Development ◽  
African Countries ◽  
Hydrological Variability ◽  
Challenges And Opportunities

Africa faces difficult water/sanitation legacies in the form of high hydrological variability and a multiplicity of transboundary river basins alongside poor sanitation. These challenges impeded the continent’s economic growth. Balanced investments in water resource and sanitation infrastructure and institutions are needed to increase productive uses of water, to mitigate the effect of recurrent floods and droughts, and to achieve basic water security as a platform for Africa’s economic growth. Priority should be given to investments that (a) focus on growth, (b) reduce rural poverty, (c) build climate resilience and adaptation, and (d) foster cooperation in international river basins. Because most African countries have low stocks of hydraulic infrastructure, emphasizing investments in infrastructure is appropriate for them. However, institution building and reform, improvements in water/sanitation management and operations, and strengthening of water information systems must complement growth in infrastructure. Development of institutions should be advanced in parallel with infrastructure investment.

scholarly journals Effect of hydrological variability on the biogeochemistry of estuaries across a regional climatic gradient

2018 ◽  
Vol 63 (6) ◽  
pp. 2465-2478 ◽  
Author(s):  
Paul A. Montagna ◽  
Xinping Hu ◽  
Terence A. Palmer ◽  
Michael Wetz
Keyword(s):  
Climatic Gradient ◽  
Hydrological Variability

scholarly journals Climate and hydrological variability: the catchment filtering role

2015 ◽  
Vol 19 (1) ◽  
pp. 379-387 ◽  
Author(s):  
I. Andrés-Doménech ◽  
R. García-Bartual ◽  
A. Montanari ◽  
J. B. Marco
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
Peak Flow ◽  
Flood Frequency ◽  
Annual Maximum ◽  
Return Periods ◽  
Rainfall Runoff ◽  
Maximum Peak ◽  
Hydrological Variability ◽  
The Impact

Abstract. Measuring the impact of climate change on flood frequency is a complex and controversial task. Identifying hydrological changes is difficult given the factors, other than climate variability, which lead to significant variations in runoff series. The catchment filtering role is often overlooked and thus may hinder the correct identification of climate variability signatures on hydrological processes. Does climate variability necessarily imply hydrological variability? This research aims to analytically derive the flood frequency distribution based on realistic hypotheses about the rainfall process and the rainfall–runoff transformation. The annual maximum peak flow probability distribution is analytically derived to quantify the filtering effect of the rainfall–runoff process on climate change. A sensitivity analysis is performed according to typical semi-arid Mediterranean climatic and hydrological conditions, assuming a simple but common scheme for the rainfall–runoff transformation in small-size ungauged catchments, i.e. the CN-SCS model. Variability in annual maximum peak flows and its statistical significance are analysed when changes in the climatic input are introduced. Results show that depending on changes in the annual number of rainfall events, the catchment filtering role is particularly significant, especially when the event rainfall volume distribution is not strongly skewed. Results largely depend on the return period: for large return periods, peak flow variability is significantly affected by the climatic input, while for lower return periods, infiltration processes smooth out the impact of climate change.

scholarly journals Effects of the hippopotamus on the chemistry and ecology of a changing watershed

2018 ◽  
Vol 115 (22) ◽  
pp. E5028-E5037 ◽  
Author(s):  
Keenan Stears ◽  
Douglas J. McCauley ◽  
Jacques C. Finlay ◽  
James Mpemba ◽  
Ian T. Warrington ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Aquatic Insect ◽  
Dry Season ◽  
Fish Abundance ◽  
Sub Saharan Africa ◽  
Aquatic Communities ◽  
Wet Season ◽  
Water Abstraction ◽  
Hydrological Variability ◽  
Invertebrate Diversity

Cross-boundary transfers of nutrients can profoundly shape the ecology of recipient systems. The common hippopotamus, Hippopotamus amphibius, is a significant vector of such subsidies from terrestrial to river ecosystems. We compared river pools with high and low densities of H. amphibius to determine how H. amphibius subsidies shape the chemistry and ecology of aquatic communities. Our study watershed, like many in sub-Saharan Africa, has been severely impacted by anthropogenic water abstraction reducing dry-season flow to zero. We conducted observations for multiple years over wet and dry seasons to identify how hydrological variability influences the impacts of H. amphibius. During the wet season, when the river was flowing, we detected no differences in water chemistry and nutrient parameters between pools with high and low densities of H. amphibius. Likewise, the diversity and abundance of fish and aquatic insect communities were indistinguishable. During the dry season, however, high-density H. amphibius pools differed drastically in almost all measured attributes of water chemistry and exhibited depressed fish and insect diversity and fish abundance compared with low-density H. amphibius pools. Scaled up to the entire watershed, we estimate that H. amphibius in this hydrologically altered watershed reduces dry-season fish abundance and indices of gamma-level diversity by 41% and 16%, respectively, but appears to promote aquatic invertebrate diversity. Widespread human-driven shifts in hydrology appear to redefine the role of H. amphibius, altering their influence on ecosystem diversity and functioning in a fashion that may be more severe than presently appreciated.

Greenhouse gas dynamics in an anthropogenically modified tropical river continuum

2021 ◽  
Author(s):  
Siddhartha Sarkar ◽  
Ajayeta Rathi ◽  
Sanjeev Kumar
Keyword(s):  
Flow Regime ◽  
Residence Time ◽  
Large Scale ◽  
Channel Length ◽  
Western India ◽  
River Continuum ◽  
Significant Control ◽  
Process Dynamics ◽  
Sabarmati River ◽  
The City

<p>Recent decades have witnessed large scale modifications in the natural flow regime of river systems. What follows are shifts in various instream processes that ultimately govern the air-water fluxes of major greenhouse gases (GHGs) like CH<sub>4</sub>, CO<sub>2</sub>, and N<sub>2</sub>O. However, due to paucity of data, the process dynamics and controls on fluxes of GHGs in tropical rivers are understudied, contributing to uncertainty in their global budget. In this study, an attempt was made to estimate the fluxes of GHGs and thereby decipher the controls on evasive processes in an anthropogenically affected Sabarmati River (catchment ~ 27,674 km<sup>2</sup> and channel length ~371 km) located in semi-arid western India. After originating from a relatively pristine region, Sabarmati passes through a major twin city (Ahmedabad-Gandhinagar), where construction of a riverfront resulted in increased residence time of water within the city limits.</p><p>To compare and understand changes in in-stream biogeochemical processes as a result of human interventions, sampling was carried out at 50 sites along the Sabarmati river continuum and a parallel running, but not so anthropogenically modified, Mahi River along with their tributaries. Results indicated relatively lower fluxes of GHGs in pristine upstream of Sabarmati and Mahi River continuum with CH<sub>4</sub>, CO<sub>2</sub> and N<sub>2</sub>O fluxes at 0.99 ± 0.35 mg C m<sup>-2 </sup>d<sup>-1</sup>, 4250.99 ± 477.74 mg C m<sup>-2 </sup>d<sup>-1 </sup>and 0.055 ± 0.026 mg N m<sup>-2 </sup>d<sup>-1</sup> respectively. The effect of higher residence time of water could be seen in the riverfront with increased CH<sub>4 </sub>and N<sub>2</sub>O fluxes at 3.27 ± 1.02 mg C m<sup>-2 </sup>d<sup>-1 </sup>and 0.129 ± 0.024 mg N m<sup>-2 </sup>d<sup>-1</sup>, respectively. However, the CO<sub>2</sub> flux did not show much increase. The fluxes increased significantly post city limits until its mouth in the Arabian Sea with extremely large flux for methane (CH<sub>4</sub>: 102.84 ± 41.32 mg C m<sup>-2 </sup>d<sup>-1</sup>, CO<sub>2</sub>: 9563.58 ± 1252.43 mg C m<sup>-2 </sup>d<sup>-1</sup>, and N<sub>2</sub>O: 0.16 ± 0.11 mg N m<sup>-2 </sup>d<sup>-1</sup>, respectively). Overall, it appeared that even within the anthropogenically stressed river, the nature of flow regime, exerts significant control on cycling of elements leading to differential fluxes. Also, the level of coupling between nitrogen and carbon appeared to change within the course of the river.</p>

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