scholarly journals Assessment of ecologically relevant hydrological change in China due to water use and reservoirs

2008 ◽  
Vol 18 ◽  
pp. 25-30 ◽  
Author(s):  
J. Zhang ◽  
P. Döll
Keyword(s):  
Water Use ◽  
Water Consumption ◽  
River Discharge ◽  
River Flow ◽  
Agricultural Land ◽  
Southern China ◽  
Flow Regimes ◽  
Ecological Impacts ◽  
Water Diversion

Abstract. As China's economy booms, increasing water use has significantly affected hydro-geomorphic processes and thus the ecology of surface waters. A large variety of hydrological changes arising from human activities such as reservoir construction and management, water abstraction, water diversion and agricultural land expansion have been sustained throughout China. Using the global scale hydrological and water use model WaterGAP, natural and anthropogenically altered flow conditions are calculated, taking into account flow alterations due to human water consumption and 580 large reservoirs. The impacts resulting from water consumption and reservoirs have been analyzed separately. A modified "Indicators of Hydrologic Alteration" approach is used to describe the human pressures on aquatic ecosystems due to anthropogenic alterations in river flow regimes. The changes in long-term average river discharge, average monthly mean discharge and coefficients of variation of monthly river discharges under natural and impacted conditions are compared and analyzed. The indicators show very significant alterations of natural river flow regimes in a large part of northern China and only minor alterations in most of southern China. The detected large alterations in long-term average river discharge, the seasonality of flows and the inter-annual variability in the northern half of China are very likely to have caused significant ecological impacts.

scholarly journals Impact of climate change on freshwater ecosystems: a global-scale analysis of ecologically relevant river flow alterations

2010 ◽  
Vol 14 (5) ◽  
pp. 783-799 ◽  
Author(s):  
P. Döll ◽  
J. Zhang
Keyword(s):  
Climate Change ◽  
River Discharge ◽  
River Flow ◽  
Flow Regimes ◽  
Freshwater Ecosystems ◽  
Land Area ◽  
Impact Of Climate Change ◽  
Water Withdrawals ◽  
The Impact

Abstract. River flow regimes, including long-term average flows, seasonality, low flows, high flows and other types of flow variability, play an important role for freshwater ecosystems. Thus, climate change affects freshwater ecosystems not only by increased temperatures but also by altered river flow regimes. However, with one exception, transferable quantitative relations between flow alterations and ecological responses have not yet been derived. While discharge decreases are generally considered to be detrimental for ecosystems, the effect of future discharge increases is unclear. As a first step towards a global-scale analysis of climate change impacts on freshwater ecosystems, we quantified the impact of climate change on five ecologically relevant river flow indicators, using the global water model WaterGAP 2.1g to simulate monthly time series of river discharge with a spatial resolution of 0.5 degrees. Four climate change scenarios based on two global climate models and two greenhouse gas emissions scenarios were evaluated. We compared the impact of climate change by the 2050s to the impact of water withdrawals and dams on natural flow regimes that had occurred by 2002. Climate change was computed to alter seasonal flow regimes significantly (i.e. by more than 10%) on 90% of the global land area (excluding Greenland and Antarctica), as compared to only one quarter of the land area that had suffered from significant seasonal flow regime alterations due to dams and water withdrawals. Due to climate change, the timing of the maximum mean monthly river discharge will be shifted by at least one month on one third on the global land area, more often towards earlier months (mainly due to earlier snowmelt). Dams and withdrawals had caused comparable shifts on less than 5% of the land area only. Long-term average annual river discharge is predicted to significantly increase on one half of the land area, and to significantly decrease on one quarter. Dams and withdrawals had led to significant decreases on one sixth of the land area, and nowhere to increases. Thus, by the 2050s, climate change may have impacted ecologically relevant river flow characteristics more strongly than dams and water withdrawals have up to now. The only exception refers to the decrease of the statistical low flow Q90, with significant decreases both by past water withdrawals and future climate change on one quarter of the land area. However, dam impacts are likely underestimated by our study. Considering long-term average river discharge, only a few regions, including Spain, Italy, Iraq, Southern India, Western China, the Australian Murray Darling Basin and the High Plains Aquifer in the USA, all of them with extensive irrigation, are expected to be less affected by climate change than by past anthropogenic flow alterations. In some of these regions, climate change will exacerbate the discharge reductions, while in others climate change provides opportunities for reducing past reductions. Emissions scenario B2 leads to only slightly reduced alterations of river flow regimes as compared to scenario A2 even though emissions are much smaller. The differences in alterations resulting from the two applied climate models are larger than those resulting from the two emissions scenarios. Based on general knowledge about ecosystem responses to flow alterations and data related to flow alterations by dams and water withdrawals, we expect that the computed climate change induced river flow alterations will impact freshwater ecosystems more strongly than past anthropogenic alterations.

scholarly journals Impact of climate change on freshwater ecosystems: a global-scale analysis of ecologically relevant river flow alterations

2010 ◽  
Vol 7 (1) ◽  
pp. 1305-1342 ◽  
Author(s):  
P. Döll ◽  
J. Zhang
Keyword(s):  
Climate Change ◽  
River Discharge ◽  
River Flow ◽  
Flow Regimes ◽  
Freshwater Ecosystems ◽  
Land Area ◽  
Impact Of Climate Change ◽  
Water Withdrawals ◽  
The Impact

Abstract. River flow regimes, including long-term average flows, seasonality, low flows, high flows and other types of flow variability, play an important role for freshwater ecosystems. Thus, climate change affects freshwater ecosystems not only by increased temperatures but also by altered river flow regimes. However, with one exception, transferable quantitative relations between flow alterations and ecosystem responses have not yet been derived. While discharge decreases are generally considered to be detrimental for ecosystems, the effect of future discharge increases is unclear. As a first step towards a global-scale analysis of climate change impacts on freshwater ecosystems, we quantified the impact of climate change on five ecologically relevant river flow indicators, using the global water model WaterGAP 2.1g to simulate monthly time series of river discharge with a spatial resolution of 0.5 degrees. Four climate change scenarios based on two global climate models and two greenhouse gas emissions scenarios were evaluated. We compared the impact of climate change by the 2050s to the impact of water withdrawals and dams on natural flow regimes that had occurred by 2002. Climate change was computed to alter seasonal flow regimes significantly (i.e. by more than 10%) on 90% of the global land area (excluding Greenland and Antarctica), as compared to only one quarter of the land area that had suffered from significant seasonal flow regime alterations due to dams and water withdrawals. Due to climate change, the timing of the maximum mean monthly river discharge will be shifted by at least one month on one third on the global land area, more often towards earlier months (mainly due to earlier snowmelt). Dams and withdrawals had caused comparable shifts on less than 5% of the land area only. Long-term average annual river discharge is predicted to significantly increase on one half of the land area, and to significantly decrease on one quarter. Dams and withdrawals had led to significant decreases on one sixth of the land area, and nowhere to increases. Thus, by the 2050s, climate change will have impacted ecologically relevant river flow characteristics much more strongly than dams and water withdrawals have up to now. The only exception refers to the decrease of the statistical low flow Q90, with significant decreases both by past water withdrawals and future climate change on one quarter of the land area. Considering long-term average river discharge, only a few regions, including Spain, Italy, Iraq, Southern India, Western China, the Australian Murray Darling Basin and the High Plains Aquifer in the USA, all of them with extensive irrigation, are expected to be less affected by climate change than by past anthropogenic flow alterations. In some of these regions, climate change will exacerbate the discharge reduction. Emissions scenario B2 leads to only slightly reduced alterations of river flow regimes as compared to scenario A2 even though emissions are much smaller. The differences in alterations resulting from the two applied climate models are larger than those resulting from the two emissions scenarios. Based on general knowledge about ecosystem responses to flow alterations and data related to flow alterations by dams and water withdrawals, we expect that the computed climate change induced river flow alterations will impact freshwater ecosystems more strongly than past anthropogenic alterations.

scholarly journals Global-scale analysis of river flow alterations due to water withdrawals and reservoirs

2009 ◽  
Vol 13 (12) ◽  
pp. 2413-2432 ◽  
Author(s):  
P. Döll ◽  
K. Fiedler ◽  
J. Zhang
Keyword(s):  
Water Use ◽  
River Discharge ◽  
River Flow ◽  
Global Scale ◽  
Land Area ◽  
Operation Rules ◽  
Western Asia ◽  
Water Withdrawals ◽  
The Impact

Abstract. Global-scale information on natural river flows and anthropogenic river flow alterations is required to identify areas where aqueous ecosystems are expected to be strongly degraded. Such information can support the identification of environmental flow guidelines and a sustainable water management that balances the water demands of humans and ecosystems. This study presents the first global assessment of the anthropogenic alteration of river flow regimes, in particular of flow variability, by water withdrawals and dams/reservoirs. Six ecologically relevant flow indicators were quantified using an improved version of the global water model WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river discharge as affected by human water withdrawals and dams around the year 2000, as well as naturalized discharge without this type of human interference. Compared to naturalized conditions, long-term average global discharge into oceans and internal sinks has decreased by 2.7% due to water withdrawals, and by 0.8% due to dams. Mainly due to irrigation, long-term average river discharge and statistical low flow Q90 (monthly river discharge that is exceeded in 9 out of 10 months) have decreased by more than 10% on one sixth and one quarter of the global land area (excluding Antarctica and Greenland), respectively. Q90 has increased significantly on only 5% of the land area, downstream of reservoirs. Due to both water withdrawals and reservoirs, seasonal flow amplitude has decreased significantly on one sixth of the land area, while interannual variability has increased on one quarter of the land area mainly due to irrigation. It has decreased on only 8% of the land area, in areas downstream of reservoirs where consumptive water use is low. The impact of reservoirs is likely underestimated by our study as small reservoirs are not taken into account. Areas most affected by anthropogenic river flow alterations are the Western and Central USA, Mexico, the western coast of South America, the Mediterranean rim, Southern Africa, the semi-arid and arid countries of the Near East and Western Asia, Pakistan and India, Northern China and the Australian Murray-Darling Basin, as well as some Arctic rivers. Due to a large number of uncertainties related e.g. to the estimation of water use and reservoir operation rules, the analysis is expected to provide only first estimates of river flow alterations that should be refined in the future.

Steam sterilisation’s energy and water footprint

2017 ◽  
Vol 41 (1) ◽  
pp. 26 ◽  
Author(s):  
Forbes McGain ◽  
Graham Moore ◽  
Jim Black
Keyword(s):  
Life Cycle ◽  
Water Use ◽  
Water Consumption ◽  
Environmental Effects ◽  
Input Data ◽  
Life Cycles ◽  
Environmental Footprint ◽  
Hospital Equipment ◽  
Load Mass

Objective The aim of the present study was to quantify hospital steam steriliser resource consumption to provide baseline environmental data and identify possible efficiency gains. We sought to find the amount of steriliser electricity and water used for active cycles and for idling (standby), and the relationship between the electricity and water consumption and the mass and type of items sterilised. Methods We logged a hospital steam steriliser’s electricity and water meters every 5 min for up to 1 year. We obtained details of all active cycles (standard 134°C and accessory or ‘test’ cycles), recording item masses and types. Relationships were investigated for both the weight and type of items sterilised with electricity and water consumption. Results Over 304 days there were 2173 active cycles, including 1343 standard 134°C cycles that had an average load mass of 21.2 kg, with 32% of cycles <15 kg. Electricity used for active cycles was 32 652 kWh (60% of total), whereas the water used was 1 243 495 L (79%). Standby used 21 457 kWh (40%) electricity and 329 200 L (21%) water. Total electricity and water consumption per mass sterilised was 1.9 kWh kg–1 and 58 L kg–1, respectively. The linear regression model predicting electricity use was: kWh = 15.7+ 0.14 × mass (in kg; R2 = 0.58, P < 0.01). Models for water and item type were poor. Electricity and water use fell from 3 kWh kg–1 and 200 L kg–1, respectively, for 5-kg loads to 0.5 kWh kg–1 and 20 L kg–1, respectively, for 40-kg loads. Conclusions Considerable electricity and water use occurred during standby, load mass was only moderately predictive of electricity consumption and light loads were common yet inefficient. The findings of the present study are a baseline for steam sterilisation’s environmental footprint and identify areas to improve efficiencies. What is known about the topic? There is increasing interest in the environmental effects of healthcare. Life cycle assessment (‘cradle to grave’) provides a scientific method of analysing environmental effects. Although data of the effects of steam sterilisation are integral to the life cycles of reusable items and procedures using such items, there are few data available. Further, there is scant information regarding the efficiency of the long-term in-hospital use of sterilisers. What does this paper add? We quantified, for the first time, long-term electricity and water use of a hospital steam steriliser. We provide useful input data for future life cycle assessments of all reusable, steam-sterilised equipment. Further, we identified opportunities for improved steriliser efficiencies, including rotating off idle sterilisers and reducing the number of light steriliser loads. Finally, others could use our methods to examine steam sterilisers and many other energy-intensive items of hospital equipment. What are the implications for practitioners? We provide useful input data for all researchers examining the environmental footprint of reusable hospital equipment and procedures using such equipment. As a result of the present study, staff in the hospital sterile supply department have reduced steam steriliser electricity and water use considerably without impeding sterilisation throughput (and reduced time inefficiencies). Many other hospitals could benefit from similar methods to improve steam steriliser and other hospital equipment efficiencies.

Surface energy balance algorithm for land-based consumption water use of different land use-cover types in arid-semiarid regions

2016 ◽  
Vol 16 (6) ◽  
pp. 1497-1513
Author(s):  
Shereif H. Mahmoud ◽  
A. A. Alazba
Keyword(s):  
Land Use ◽  
Energy Balance ◽  
Surface Energy ◽  
Water Use ◽  
Water Consumption ◽  
Surface Energy Balance ◽  
Agricultural Land ◽  
Eastern Province ◽  
Very High ◽  
Coastal Lowlands

Spatiotemporal distributions of water consumption for various land use-cover types over the Eastern province of Saudi Arabia were estimated using Surface Energy Balance Algorithm. Water consumption of various land use and cover classes shows similar seasonal dynamic trends. The spatial distribution of annual actual evapotranspiration (AET) shows low values in the Empty Quarter (231–438 mm/yr), and moderate values in the Eastern Province borders (439–731 mm/yr). Very high AET values were observed in irrigated croplands in the Northern plains, Hafar Al-Batin, the central coastal lowlands, and the southern coastal lowlands, where annual AET ranged from 732 to 1,790 mm/yr, representing the majority of the study area agricultural land. Evaporative behavior of land use-cover types indicated that irrigated cropland, which occupies 0.37% of the study area, has an average daily AET ranging from 9.2 mm/day in January to a maximum value in April (30 mm/day). Average annual water use by irrigated cropland is relatively very high and it is roughly 1,786.9 mm/yr, while water bodies, which cover 0.023% (121.2 km2) of the study area, also had relatively high mean AET (660.8 mm/yr). Overall, AET rates for irrigated cropland are much higher than for other land uses.

scholarly journals What does rebounding water use look like? An examination of post-drought and post-flood water end-use demand in Queensland, Australia

2014 ◽  
Vol 14 (4) ◽  
pp. 561-568 ◽  
Author(s):  
C. D. Beal ◽  
A. Makki ◽  
R. A. Stewart
Keyword(s):  
Water Use ◽  
Water Consumption ◽  
Demand Management ◽  
Management Policy ◽  
Dry Period ◽  
Residential Water Consumption ◽  
End Use ◽  
Capacity Data ◽  
Residential Water

Rebounding water use behaviour has been observed in communities that have experienced plentiful water supply following a very dry period. However, the drivers of such rebounds in water consumption are varied and not well understood. Knowledge of such drivers can greatly assist managers towards proactive demand management, modelling and timely promotion of water efficient behaviours. Total and end-use residential water consumption has been tracked in South East Queensland, Australia for a sample of up to 252 homes in post-drought conditions (dam supplies growing but water restrictions continued, changed water use behaviours still ‘fresh’), and during and post-flooding conditions (eased restrictions, 100% dam capacity). Data on end-use water consumption trends using nearly 3 years of residential water end-use data have revealed several interesting patterns of consumption such as a delayed return to pre-drought use, the influence of climate and end-use specific rebounds (e.g. indoor versus outdoor use). The end-use data have helped to identify the drivers of rebounding water consumption which appear to include environmental cues (rainfall, temperature), social cues (e.g. government encouraging consumers to turn on tap) and a gradual general reduction in conservative water use behaviours. The paper concludes with a discussion of how this knowledge can be used to inform long-term demand management policy, particularly in variable climates.

scholarly journals Long term researches regarding the irrigation influence on sugarbeet crop inthe Crisurilor Plain

2013 ◽  
pp. 11-15
Author(s):  
Radu Brejea ◽  
Cristian Domuţa
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Water Consumption ◽  
Irrigation Water ◽  
Yield Level ◽  
Total Water Consumption ◽  
Yield Gain ◽  
Use Efficiency ◽  
Variation Interval

The paper is based on the researches carried out in the long term trial placed on the preluvosoil from Agricultural Research and Development Station Oradea, Crisurilor Plain in during 1976–2012. The soil water reserve in 0–75 cm depth decreased bellow easily available water content every year and in 32% of years the soil water reserve decreased bellow wilting point. For optimum water supply an irrigation rate of 2665 m3 ha-1 (variation interval 500–5090 m3 ha-1) was needed. The irrigation determined improving of water/temperature + light report (Domuta climate index) with 47.4% in average in the period May–September. A statistically very significant connection was quantified between this indicator and the yield. Daily water consumption increased in the irrigated variant, the biggest difference in comparison with unirrigated variant was registered in August, 86% in comparison with unirrigated variant. As consequence, the value of the total water consumption increased with 50%, variation interval was 11–154%. The irrigation covered 37.8% of total water consumption, the variation interval was 8.3%–67.9%. The yield level of the sugarbeet increased in average with 61%, the variation interval was 9–227%. Standard deviation was lower in the irrigated variant and this emphasizes an improve of the yield stability with 25.1%. The sugar content of the sugarbeet roots from irrigated variant increased statistically very significantly in the droughty years and differs significantly in the rainy years. Water use efficiency increased in the irrigated variant with 7% and irrigation water use efficiency was between 7.9 kg yield gain 1 m-3 irrigation water and 17.4 kg yield gain 1 m-3 irrigation water. The positive influence of the irrigation on microclimate, water consumption, yield level, stability and quality and on water use efficiency sustain the need of the irrigation in sugarbeet from Crisurilor Plain.

scholarly journals The Influence of Rainfall and Land Use/Land Cover Changes on River Discharge Variability in the Mountainous Catchment of the Bagmati River

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2444 ◽  
Author(s):  
Dinesh Tuladhar ◽  
Ashraf Dewan ◽  
Michael Kuhn ◽  
Robert J. Corner
Keyword(s):  
Land Use ◽  
Land Cover ◽  
River Discharge ◽  
Forest Cover ◽  
Agricultural Land ◽  
Strong Association ◽  
Land Use Land Cover ◽  
Discharge Data ◽  
Bagmati River

Changes in rainfall and land use/land cover (LULC) can influence river discharge from a catchment in many ways. Homogenized river discharge data from three stations and average rainfall records, interpolated from 13 stations, were examined for long-term trends and decadal variations (1970–2017) in the headwater, upper and middle catchments of the Bagmati River. LULC changes over five decades were quantified using multitemporal Landsat images. Mann–Kendall tests on annual time series showed a significant decrease in river discharge (0.61% per year) from the entire Bagmati catchment, although the decrease in rainfall was statistically insignificant. However, declines in river discharge and rainfall were both significant in upper catchment. Decadal departures from long-term means support these trend results. Over tenfold growth in urban area and a decrease in agricultural land were observed in the upper catchment, while forest cover slightly increased in the entire catchment between 1975 and 2015. Correlation analysis showed a strong association between surface runoff, estimated using the curve number method, observed river discharge and rainfall in the upper catchment, while the relationship was weaker in the headwater catchment. These results were also supported by multiple regression analysis, suggesting that human activities together with climate change have contributed to river discharge changes in the Bagmati catchment.

scholarly journals Hydrology of the Po River: looking for changing patterns in river discharge

2012 ◽  
Vol 9 (5) ◽  
pp. 6689-6713
Author(s):  
A. Montanari
Keyword(s):  
Water Resources ◽  
River Discharge ◽  
River Flow ◽  
Temporal Distribution ◽  
Hydrological Regime ◽  
Po River ◽  
Water Abundance ◽  
Changing Patterns ◽  
The Impact

Abstract. Scientists and public administrators are devoting increasing attention to the Po River, in Italy, in view of concerns related to the impact of increasing urbanisation and exploitation of water resources. A better understanding of the hydrological regime of the river is necessary to improve water resources management and flood protection. In particular, the analysis of the effects of hydrological and climatic change is crucial for planning sustainable development and economic growth. An extremely interesting issue is to inspect to what extent river flows can be naturally affected by the occurrence of long periods of water abundance or scarcity, which can be erroneously interpreted as irreversible changes due to human impact. In fact, drought and flood periods alternatively occurred in the recent past in the form of long term cycles. This paper presents advanced graphical and analytical methods to gain a better understanding of the temporal distribution of the Po River discharge. In particular, we present an analysis of river flow variability and memory properties to better understand natural patterns and in particular long term changes, which may affect the future flood risk and availability of water resources.

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