scholarly journals Hydrochemistry and Evolution of Water Quality in a Context of Aridity and Increasing Agriculture in Three River Sub-Basins of Santiago Island (Cape Verde)

Geosciences ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 263
Author(s):  
Nemias Gonçalves ◽  
Teresa Valente ◽  
Jorge Pamplona ◽  
Isabel Margarida Horta Ribeiro Antunes

In regions under development and facing recurrent droughts, increasing the area of irrigated agriculture may create additional disruption in water resources management. The present study was focused on three river sub-basins with the highest agricultural intensity (S. Miguel, Ribeira Seca and S. Domingos) in Santiago Island (Cape Verde). Sets of wells were selected to evaluate the influence of salinization and agriculture practices on the hydrochemistry. This assessment was performed by using data from the bibliography (2003) and a recent campaign (2016). The water chemistry indicates lower mineralization in the S. Miguel sub-basin. Nitrates and nitrites, typically associated with diffuse pollution, are present in all sub-basins, but with varying patterns. Additionally, sodium chloride waters occur in all the three sub-basins, especially those closest to the coastline. In turn, a bicarbonate-magnesium facies was identified in S. Domingos, at the furthest point from the coast, indicating a geological control. The comparison between the two periods suggests a decrease in water quality. The rising extension of the irrigation area associated with aridity should intensify the already observed soil salinization. Thus, the present review highlights the strategic importance of water monitoring at the basin level as a management tool for resources preservation in insular arid and developing regions.

2021 ◽  
Vol 9 ◽  
Author(s):  
Ilan Stavi ◽  
Niels Thevs ◽  
Simone Priori

Soil salinization and sodification are common processes that particularly characterize drylands. These processes can be attributed either to natural conditions or anthropogenic activities. While natural causes include factors such as climate, lithology, topography, and pedology, human causes are mostly related to agricultural land-use, and specifically, to irrigated agriculture. The objective of this study was to thoroughly review this topic, while highlighting the major challenges and related opportunities. Over time, the extent of saline, sodic, and saline-sodic croplands has increased, resulting in accelerated land degradation and desertification, decreased agricultural productivity, and consequently jeopardizing environmental and food security. Mapping and monitoring saline soils is an important management tool, aimed at determining the extent and severity of salinization processes. Recent developments in advanced remote sensing methods have improved the efficacy of mapping and monitoring saline soils. Knowledge on prevention, mitigation, and recovery of soil salinity and sodicity has substantially grown over time. This knowledge includes advanced measures for salt flushing and leaching, water-saving irrigation technologies, precision fertilizer systems, chemical restoration, organic and microbial remediation, and phytoremediation of affected lands. Of a particular interest is the development of forestry-related means, with afforestation, reforestation, agroforestry, and silvopasture practices for the recovery of salt-affected soils. The forecasted expansion of drylands and aggravated drying of existing drylands due to climatic change emphasize the importance of this topic.


Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2888
Author(s):  
Manuela Morais ◽  
Alexandra Marchã Penha ◽  
Maria Helena Novais ◽  
Leonel Landim ◽  
Sónia Silva Victória ◽  
...  

Reservoirs provide valuable services to human beings, especially in arid, semi-arid, and Mediterranean regions affected by water scarcity. The present effort aims to study the environmental descriptors of variation and the main factors influencing phytoplankton composition, structure, and diversity in five reservoirs in Santiago Island, Cape Verde, a region affected by water availability. Five campaigns took place from 2016 to 2020 to sample phytoplankton and measure environmental variables according to standard analytical methodologies. Environmental results (17 water physicochemical variables, air temperature, and precipitation) revealed that reservoirs differ in the geological influence variables. The high levels of P and N in water seem to be related to Land Use/Land Cover and are responsible for water-quality degradation. Cyanobacteria dominated the phytoplankton community and posed high risk levels, especially considering that the identified taxa are potential producers of different toxins. Taxa responsible for this dominance were not the same in all reservoirs, emphasizing the dominant role of local habitat factors on community composition and diversity. Overall, the results reveal the importance of defining integrated management plans/strategies for the set of five studied reservoirs, since the processes influencing variation in the phytoplankton community are temporal-scale dependent, with similar biogeographic patterns.


2010 ◽  
Vol 5 (4) ◽  
Author(s):  
J. L. Manuszak ◽  
M. MacPhee ◽  
S. Liskovich ◽  
L. Feldsher

The City of Baltimore, Maryland is one of many US cities faced with challenges related to increasing potable water demands, diminishing fresh water supplies, and aging infrastructure. To address these challenges, the City recently undertook a $7M study to evaluate water supply and treatment alternatives and develop the conceptual design for a new 120 million gallon per day (MGD) water treatment plant. As part of this study, an innovative raw water management tool was constructed to help model source water availability and predicted water quality based on integration of a new and more challenging surface water supply. A rigorous decision-making approach was then used to screen and select appropriate treatment processes. Short-listed treatment strategies were demonstrated through a year-long pilot study, and process design criteria were collected in order to assess capital and operational costs for the full-scale plant. Ultimately the City chose a treatment scheme that includes low-pressure membrane filtration and post-filter GAC adsorption, allowing for consistent finished water quality irrespective of which raw water supply is being used. The conceptual design includes several progressive concepts, which will: 1) alleviate treatment limitations at the City's existing plants by providing additional pre-clarification facilities at the new plant; and 2) take advantage of site conditions to design and operate the submerged membrane system by gravity-induced siphon, saving the City significant capital and operations and maintenance (O&M) costs. Once completed, the new Fullerton Water Filtration Plant (WFP) will be the largest low-pressure membrane plant in North America, and the largest gravity-siphon design in the world.


1994 ◽  
Vol 29 (3) ◽  
pp. 95-106
Author(s):  
Alfred P. Benoist ◽  
Gerard H. Broseliske

For priority pollutants, the international Rhine Action Programme (RAP) aims to meet the quality objectives for the Rhine, set by the International Rhine Commission (IRC), by the year 2000. An assessment must be carried out to define additional measures exceeding best available technology (BAT) for point sources and best environmental practice (BEP) for diffuse sources for those priority pollutants still violating the quality objectives of the Rhine after implementing BAT and BEP only. To carry out the required assessments, an excessive amount of work and money is needed, including the application of sophisticated calculation models. For prioritizing reasons, the Institute for Inland Water Management and Waste Water Treatment (RIZA) initiated a project called EVER, which was conducted by DHV Water BV. EVER is the abbreviation of the Dutch equivalent for Effective Distribution of Emission Reductions (Effective Verdeling van Emissie Reducties). The aim of this project is to carry out a first and crude evaluation of the impact of abatement measures (BAT and BEP), as set by the IRC for the period 1985-1995. For those pollutants still showing a violation of the quality objectives for the Rhine in the year 1995, a range finding method is used, to predict the costs and impact of abatement measures exceeding BAT and BEP on the water quality of the Rhine. So, EVER is a management tool to prioritize the work to be done within the frame-work of the IRC, triggering the application of e.g. sophisticated calculation models for a selected number of priority pollutants. In EVER, the prognosis of the reduction of specific discharge rates for approximately forty priority pollutants is given for twelve sub-catchment areas for the year 1995. This prognosis is used to predict concentrations at eight international monitoring locations in the Rhine basin, using the discharges and concentrations of the year 1985 as a reference. The predicted concentrations for the year 1995 are compared with the (preliminary) water quality objectives as set by the IRC. The results indicate, that for six of the selected pollutants the number of available data is too small for sound predictions. Fifteen of the selected pollutants will satisfy the water quality objectives in 1995. Twenty (half) of the selected pollutants will still violate the quality objectives at several monitoring locations. These twenty pollutants are the basis for priorities to be set within the frame-work of the IRC for phase 3 (1995-2000) of the RAP. For these pollutants, additional abatement measures exceeding BAT and BEP are selected in EVER for the manageable groups of sources (anthropogenic non-point sources, industrial sources and municipal sources). Each measure is analyzed separately for costs and effectiveness. Finally the results of this project are integrated into a matrix system which will enable us to select the most effective mix of pollution abatement measures at the lowest costs. The result of the selected additional measures exceeding BAT and BEP shows that 17 pollutants will still violate the quality objectives.


2021 ◽  
Author(s):  
Mohammad Taghi Sattari ◽  
Hajar Feizi ◽  
Muslume Sevba Colak ◽  
Ahmet Ozturk ◽  
Fazli Ozturk ◽  
...  

2011 ◽  
Vol 101 (3) ◽  
pp. 448-453 ◽  
Author(s):  
Joshua Graff Zivin ◽  
Matthew Neidell ◽  
Wolfram Schlenker

We examine the impact of poor water quality on avoidance behavior by estimating the change in bottled water purchases in response to drinking water violations. Using data from a national grocery chain matched with water quality violations, we find an increase in bottled water sales of 22 percent from violations due to microorganisms and 17 percent from violations due to elements and chemicals. Back-of-the envelope calculations yield costs of avoidance behavior at roughly $60 million for all nationwide violations in 2005, which likely reflects a significant understatement of the total willingness to pay to eliminate violations.


Climate ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 92
Author(s):  
Tewodros R. Godebo ◽  
Marc A. Jeuland ◽  
Christopher J. Paul ◽  
Dagnachew L. Belachew ◽  
Peter G. McCornick

This work aims to assess water quality for irrigated agriculture, alongside perceptions and adaptations of farmers to climate change in the Main Ethiopian Rift (MER). Climate change is expected to cause a rise in temperature and variability in rainfall in the region, reducing surface water availability and raising dependence on groundwater. The study data come from surveys with 147 farmers living in the Ziway–Shala basin and water quality assessments of 162 samples from groundwater wells and surface water. Most groundwater samples were found to be unsuitable for long term agricultural use due to their high salinity and sodium adsorption ratio, which has implications for soil permeability, as well as elevated bicarbonate, boron and residual sodium carbonate concentrations. The survey data indicate that water sufficiency is a major concern for farmers that leads to frequent crop failures, especially due to erratic and insufficient rainfall. An important adaptation mechanism for farmers is the use of improved crop varieties, but major barriers to adaptation include a lack of access to irrigation water, credit or savings, appropriate seeds, and knowledge or information on weather and climate conditions. Local (development) agents are identified as vital to enhancing farmers’ knowledge of risks and solutions, and extension programs must therefore continue to promote resilience and adaptation in the area. Unfortunately, much of the MER groundwater that could be used to cope with declining viability of rainfed agriculture and surface water availability, is poor in quality. The use of saline groundwater could jeopardize the agricultural sector, and most notably commercial horticulture and floriculture activities. This study highlights the complex nexus of water quality and sufficiency challenges facing the agriculture sector in the region, and should help decision-makers to design feasible strategies for enhancing adaptation and food security.


2003 ◽  
Vol 48 (10) ◽  
pp. 47-53 ◽  
Author(s):  
H. Reuter ◽  
G. Krause ◽  
A. Mönig ◽  
M. Wulkow ◽  
H. Horn

The water quality management tool RIONET for river basins has been developed with regard to the EU Water Framework Directive. The management tool can simulate the water quality in catchment basins not only in the dimension of a single river but in whole river networks. A submodel of the IWA River Water Quality Model No. 1 is used in RIONET. The river model is based on the assumption that self purification processes in the river takes place both in the benthic biofilm and the bulk water phase. Laboratory experiments with sediment cores underline the major role of the benthic biofilm. The input parameters of the management tool such as volumetric flow rates from waste water treatment plants and flow velocities and discharge in the main river and its tributaries can be loaded directly from geographic information systems (GIS). The subcatchment basin of the river Bode in Saxon Anhalt was used for test runs of RIONET.


1998 ◽  
Vol 33 (4) ◽  
pp. 519-550 ◽  
Author(s):  
Paul A. Zandbergen ◽  
Ken J. Hall

Abstract The use of indices in ecosystem management is attractive because it allows for the representation of a complex set of information on ecosystem variables in a simple fashion. Recently the British Columbia Ministry of Environment, Lands and Parks developed the British Columbia Water Quality Index (BCWQI). As this index is currently being considered as the basis for other provincial indices and a national water quality index, the character of the BCWQI needs to be carefully considered. This study evaluates the performance of the BCWQI and assesses how useful and appropriate it is as a management tool at the watershed level. For this purpose the index is used to express the results of two sampling programs, one by the British Columbia Ministry of Environment, Lands and Parks, and the other by the Westwater Research Centre, of two relatively small watersheds in the Greater Vancouver area: the Brunette River watershed, heavily impacted by urbanization, and the Salmon River watershed on the urban-rural fringe. For both watersheds the intended use is the protection of aquatic life and only those water quality objectives are considered. The results indicate that the BCWQI is extremely sensitive to sampling design and highly dependent on the specific application of water quality objectives. A comparison is made with another type of index in widespread use in North America: the National Sanitation Foundation Water Quality Index (NSFWQI). This index appears promising for stream stewardship groups because of its simplicity and ease of use. For watershed managers, an alternative to the BCWQI is suggested, based on exceedance factors for individual objectives. This Simple Water Quality Index (SWQI) recognizes the importance of objectives that are specific to a particular water body, but overcomes some of the limitations of the BCWQI. A presentation format is suggested for objective exceedance factors, with a clear indication of exactly which objectives were included — without this, the final numerical index value is meaningless. This study suggests that the BCWQI in its current form has serious limitations for comparing water bodies and for establishing management priorities. If local watershed managers use the BCWQI in guiding efforts to protect aquatic resources, they should consider these limitations carefully.


Sign in / Sign up

Export Citation Format

Share Document