Humans create vast quantities of wastewater through inefficiencies and poor management of water systems. The wasting of water poses sustainability challenges, depletes energy reserves, and undermines ...human water security and ecosystem health. Here we review emerging approaches for reusing wastewater and minimizing its generation. These complementary options make the most of scarce freshwater resources, serve the varying water needs of both developed and developing countries, and confer a variety of environmental benefits. Their widespread adoption will require changing how freshwater is sourced, used, managed, and priced.
In semi-arid areas, many ecosystems and activities depend essentially on water availability. In Morocco, the increase of water demands combined to climate change induced decrease of precipitation put ...a lot of pressure on groundwater. This paper reports the results of updating and evaluation of groundwater datasets with regards to climate scenarios and institutional choices. The continuous imbalance between groundwater extraction and recharge caused a dramatic decline in groundwater levels (20 to 65 m in the past 30 years). Additionally, Morocco suffers from the degradation in groundwater quality due to seawater intrusion, nitrate pollution and natural salinity changes. Climate data analysis and scenarios predict that temperatures will increase by 2 to 4 °C and precipitation will decrease by 53% in all catchments over this century. Consequently, surface water availability will drastically decrease, which will lead to more extensive use of groundwater. Without appropriate measures, this situation will jeopardize water security in Morocco. In this paper, we zoom on the case the Souss-Massa basin, where management plans (artificial recharge, seawater desalination, and wastewater reuse) have been adopted to restore groundwater imbalance or, at least, mitigate the recorded deficits. These plans may save water for future generations and sustain crop production.
Artificial lakes (reservoirs) are regulated water bodies with large stage fluctuations and different interactions with groundwater compared with natural lakes. A novel modelling study characterizing ...the dynamics of these interactions is presented for artificial Lake Turawa, Poland. The integrated surface-water/groundwater MODFLOW-NWT transient model, applying SFR7, UZF1 and LAK7 packages to account for variably-saturated flow and temporally variable lake area extent and volume, was calibrated throughout 5 years (1-year warm-up, 4-year simulation), applying daily lake stages, heads and discharges as control variables. The water budget results showed that, in contrast to natural lakes, the reservoir interactions with groundwater were primarily dependent on the balance between lake inflow and regulated outflow, while influences of precipitation and evapotranspiration played secondary roles. Also, the spatio-temporal lakebed-seepage pattern was different compared with natural lakes. The large and fast-changing stages had large influence on lakebed-seepage and water table depth and also influenced groundwater evapotranspiration and groundwater exfiltration, as their maxima coincided not with rainfall peaks but with highest stages. The mean lakebed-seepage ranged from ~0.6 mm day
−1
during lowest stages (lake-water gain) to ~1.0 mm day
−1
during highest stages (lake-water loss) with largest losses up to 4.6 mm day
−1
in the peripheral zone. The lakebed-seepage of this study was generally low because of low lakebed leakance (0.0007–0.0015 day
−1
) and prevailing upward regional groundwater flow moderating it. This study discloses the complexity of artificial lake interactions with groundwater, while the proposed front-line modelling methodology can be applied to any reservoir, and also to natural lake interactions with groundwater.
The small islands in the Mediterranean Sea suffer water shortages, aggravated by pressure from tourism during the dry season. Many are affected by the intense and increasing human water demand and ...the harsh climatic and geographic nature of the island terrain. The present study, carried out on the island of Favignana, Egadi Archipelago (southern Italy), evaluates the regime of recharge to the subsurface, and hypothesizes a solution for identifying the areas where groundwater is most abundant, as well as the best management options for human use. By means of hydrological measurements and chemical analyses, a specific location has been identified in the eastern sector of the island where groundwater has optimal quality and the water table is at a depth of only a few metres. In other areas of the island the groundwater is more saline, due to seawater intrusion, and it is present only at greater depths. The residents of the island have in the past lived harmoniously with the climatic and hydrological regime of the island, and have shown good ability to manage the groundwater resources, fed by the limited precipitation that comes in winter, using it as a supplement to the drinking water supply that comes from Trapani (mainland Sicily) by a submarine pipeline and by tanker. Optimized management of the groundwater resources could reduce the volume of freshwater transferred from the mainland.
The nitrogen cycle has been radically changed by human activities
. China consumes nearly one third of the world's nitrogen fertilizers. The excessive application of fertilizers
and increased ...nitrogen discharge from livestock, domestic and industrial sources have resulted in pervasive water pollution. Quantifying a nitrogen 'boundary'
in heterogeneous environments is important for the effective management of local water quality. Here we use a combination of water-quality observations and simulated nitrogen discharge from agricultural and other sources to estimate spatial patterns of nitrogen discharge into water bodies across China from 1955 to 2014. We find that the critical surface-water quality standard (1.0 milligrams of nitrogen per litre) was being exceeded in most provinces by the mid-1980s, and that current rates of anthropogenic nitrogen discharge (14.5 ± 3.1 megatonnes of nitrogen per year) to fresh water are about 2.7 times the estimated 'safe' nitrogen discharge threshold (5.2 ± 0.7 megatonnes of nitrogen per year). Current efforts to reduce pollution through wastewater treatment and by improving cropland nitrogen management can partially remedy this situation. Domestic wastewater treatment has helped to reduce net discharge by 0.7 ± 0.1 megatonnes in 2014, but at high monetary and energy costs. Improved cropland nitrogen management could remove another 2.3 ± 0.3 megatonnes of nitrogen per year-about 25 per cent of the excess discharge to fresh water. Successfully restoring a clean water environment in China will further require transformational changes to boost the national nutrient recycling rate from its current average of 36 per cent to about 87 per cent, which is a level typical of traditional Chinese agriculture. Although ambitious, such a high level of nitrogen recycling is technologically achievable at an estimated capital cost of approximately 100 billion US dollars and operating costs of 18-29 billion US dollars per year, and could provide co-benefits such as recycled wastewater for crop irrigation and improved environmental quality and ecosystem services.
This report attempts to fill that gap
for two of the most important water-related issues facing
the effects of climate variability and the steady
degradation of the nation's water resources. The ...study
reported here concluded that the El Niño-La Niña episode
from 1997-2000 cost the country Ksh 290 billion (about 14
percent of GDP during that period). During El Niño-induced
floods, this cost primarily arises from destruction of
infrastructure such as roads, water supply infrastructure,
and pipe networks. The largest costs incurred during the La
Niña droughts (1998-2000) were from loss of industrial
production and other costs arising from reduced hydropower
generation, as well as from crop and livestock losses. These
costs are felt throughout Kenyan society.
Saltwater intrusion (SWI) is a type of pollution that adversely affects the quality of groundwater in coastal aquifers. The Nile Delta aquifer (NDA) in Egypt contains a large amount of freshwater. ...Increasing abstraction from the aquifer and sea level rise have led to an increase in SWI, which has reached up to 100 km inland. Therefore, practical measures are required to prevent further SWI. This study aims to identify an optimal well system to manage the intrusion of saline water in NDA using a number of management systems, including pumping of brackish water, aquifer recharge, and abstraction of the freshwater. SEAWAT code is used to simulate SWI in the aquifer considering different scenarios of pumping and sea level rise. Four scenarios are used to control SWI, including: decreasing pumping from the aquifer, increasing recharge using treated waste water, increasing abstraction of brackish water for desalination, and a combination of these systems. The results showed that increasing recharge could lead to greater retardation of SWI (19.5%) than decreasing pumping (6.2%) and abstraction of brackish water (5.9%). However, a combined well system of pumping, recharge and abstraction is shown to be a more effective tool to control SWI in coastal aquifers, with retardation percentage of 21.3%.
Groundwater is critical for the sustainable development of the Loess Plateau, while groundwater quality is generally poor in this area due to natural factors and anthropogenic pollution. This study ...was carried out to investigate the suitability of groundwater for domestic and agricultural purposes in Yan’an City on the Chinese Loess Plateau and to assess its implications to sustainable groundwater management on the plateau. The index levels were compared with the threshold values established by the national and the WHO drinking water guidelines, and the suitability of groundwater for irrigation purposes was assessed using multiple agricultural water quality indicators. An entropy-weighted Technique for Order Preference by Similarity to an Ideal Solution (entropy-weighted TOPSIS) was adopted for overall groundwater quality assessment. The results indicate that the study area is characterized by saline, hard, and slightly alkaline groundwater, mainly of the HCO
3
–Ca·Mg type, accompanied by some minor SO
4
·Cl–Ca·Mg type. The dissolution of carbonates and gypsum and the leaching of soluble salts are important natural processes influencing the groundwater ion chemistry. The parameters TH, TDS, and SO
4
2−
are major indices, while Fe, Mn, F
−
, and NH
4
+
are minor contaminants affecting groundwater quality. The overall groundwater quality is generally acceptable for irrigation, and most of the water is suitable for drinking. Rainwater harvesting, water quality improvement programs, regular water quality monitoring, and multidisciplinary water research programs are suggested as measures for sustainable groundwater management on the Loess Plateau.
Groundwater is an important water resource for agricultural irrigation and urban
and industrial utilization in the coastal regions of northern China. In the
past 5 decades, coastal groundwater ...salinization in the Yang–Dai river
plain has become increasingly serious under the influence of anthropogenic
activities and climatic change. It is pivotal for the scientific management
of coastal water resources to accurately understand groundwater salinization
processes and their causative factors. Hydrochemical (major ion and trace
element) and stable isotopic (δ18O and δ2H) analysis of
different water bodies (surface water, groundwater, geothermal water and
seawater) were conducted to improve understanding of groundwater salinization
processes in the plain's Quaternary aquifer. Saltwater intrusion due to
intensive groundwater pumping is a major process, either by vertical
infiltration along riverbeds which convey saline surface water inland, and/or
direct subsurface lateral inflow. Trends in salinity with depth indicate that
the former may be more important than previously assumed. The proportion of
seawater in groundwater is estimated to have reached up to 13 % in shallow
groundwater of a local well field. End-member mixing calculations also
indicate that the geothermal water with high total dissolved solids (up to 10.6 g L−1) with
depleted stable isotope compositions and elevated strontium concentrations
(> 10 mg L−1) also mixes locally with water in the overlying
Quaternary aquifers. This is particularly evident in samples with elevated
Sr ∕ Cl ratios (> 0.005 mass ratio). Deterioration of groundwater
quality by salinization is also clearly exacerbated by anthropogenic
pollution. Nitrate contamination via intrusion of heavily polluted marine
water is evident locally (e.g., in the Zaoyuan well field); however, more
widespread nitrate contamination due to other local sources such as
fertilizers and/or domestic wastewater is evident on the basis of NO3 ∕ Cl
ratios. This study provides an example of how multiple geochemical indicators
can delineate different salinization processes and guide future water
management practices in a densely populated water-stressed coastal region.
Freshwater salinization is an emerging global problem impacting safe drinking water, ecosystem health and biodiversity, infrastructure corrosion, and food production. Freshwater salinization ...originates from diverse anthropogenic and geologic sources including road salts, human-accelerated weathering, sewage, urban construction, fertilizer, mine drainage, resource extraction, water softeners, saltwater intrusion, and evaporative concentration of ions due to hydrologic alterations and climate change. The complex interrelationships between salt ions and chemical, biological, and geologic parameters and consequences on the natural, social, and built environment are called Freshwater Salinization Syndrome (FSS). Here, we provide a comprehensive overview of salinization issues (past, present, and future), and we investigate drivers and solutions. We analyze the expanding global magnitude and scope of FSS including its discovery in humid regions, connections to human-accelerated weathering and mobilization of ‘chemical cocktails.’ We also present data illustrating: (1) increasing trends in salt ion concentrations in some of the world’s major freshwaters, including critical drinking water supplies; (2) decreasing trends in nutrient concentrations in rivers due to regulations but increasing trends in salinization, which have been due to lack of adequate management and regulations; (3) regional trends in atmospheric deposition of salt ions and storage of salt ions in soils and groundwater, and (4) applications of specific conductance as a proxy for tracking sources and concentrations of groups of elements in freshwaters. We prioritize FSS research needs related to better understanding: (1) effects of saltwater intrusion on ecosystem processes, (2) potential health risks from groundwater contamination of home wells, (3) potential risks to clean and safe drinking water sources, (4) economic and safety impacts of infrastructure corrosion, (5) alteration of biodiversity and ecosystem functions, and (6) application of high-frequency sensors in state-of-the art monitoring and management. We evaluate management solutions using a watershed approach spanning air, land, and water to explore variations in sources, fate and transport of different salt ions (
e.g.
monitoring of atmospheric deposition of ions, stormwater management, groundwater remediation, and managing road runoff). We also identify tradeoffs in management approaches such as unanticipated retention and release of chemical cocktails from urban stormwater management best management practices (BMPs) and unintended consequences of alternative deicers on water quality. Overall, we show that FSS has direct and indirect effects on mobilization of diverse chemical cocktails of ions, metals, nutrients, organics, and radionuclides in freshwaters with mounting impacts. Our comprehensive review suggests what could happen if FSS were not managed into the future and evaluates strategies for reducing increasing risks to clean and safe drinking water, human health, costly infrastructure, biodiversity, and critical ecosystem services.
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