Waternet is the first water cycle company in the Netherlands, responsible for drinking water treatment and distribution, wastewater collection and treatment, and water system management and control in and around Amste...Waternet is the first water cycle company in the Netherlands, responsible for drinking water treatment and distribution, wastewater collection and treatment, and water system management and control in and around Amsterdam. Waternet started on 1 January 2006 to overcome the disadvantages of the rather fragmented organisation of the Dutch public water sector. The water cycle concept offers better opportunities to meet the future challenges in the water sector. The first four years of operation of Waternet show very promising results with respect to efficiency, customer orientation and quality improvement. To further develop the water cycle concept and to find sustainable solutions for the challenges the water sector is confronted with, Waternet focuses on six strategic innovation areas the coming years： water resources and water system; closing the water cycle; sustainability; new sanitation concepts; new products and services; management innovations.展开更多
Many cities have pledged to achieve carbon neutrality.The urban water industry can also contribute its share to a carbon-neutral future.Using a multi-city time-series analysis approach,this study aims to assess the pr...Many cities have pledged to achieve carbon neutrality.The urban water industry can also contribute its share to a carbon-neutral future.Using a multi-city time-series analysis approach,this study aims to assess the progress and lessons learned from the greenhouse gas(GHG)emissions management of urban water systems in four global cities:Amsterdam,Melbourne,New York City,and Tokyo.These cities are advanced in setting GHG emissions reduction targets and reporting GHG emissions in their water industries.All four cities have reduced the GHG emissions in their water industries,compared with those from more than a decade ago(i.e.,the latest three-year moving averages are 13%–32%lower),although the emissions have“rebounded”multiple times over the years.The emissions reductions were mainly due to various engineering opportunities such as solar and mini-hydro power generation,biogas valorization,sludge digestion and incineration optimization,and aeration system optimization.These cities have recognized the many challenges in reaching carbon-neutrality goals,which include fluctuating water demand and rainfall,more carbon-intensive flood-prevention and water-supply strategies,meeting new air and water quality standards,and revising GHG emissions accounting methods.This study has also shown that it is difficult for the water industry to achieve carbon neutrality on its own.A collaborative approach with other sectors is needed when aiming toward the city’s carbon-neutrality goal.Such an approach involves expanding the usual system boundary of the water industry to externally tap into both engineering and non-engineering opportunities.展开更多
A spatial analysis of drought characteristics in the Limpopo basin is undertaken to evaluate its regional implications to water management challenges. In this study, drought duration, frequency and severity are invest...A spatial analysis of drought characteristics in the Limpopo basin is undertaken to evaluate its regional implications to water management challenges. In this study, drought duration, frequency and severity are investigated. In addition drought Severity-Area-Frequency (SAF) curves were constructed. The entire Limpopo River Basin is subdivided into four homogeneous regions based on topographic and climate variations in the basin, which was constructed with the K-Means Clustering algorithm. Using the medium range time series of the Standardized Precipitation Index (SPI) as an indicator of drought for each homogeneous region, monthly and annual SAF curves and maps of probability of drought occurrence were produced. The results indicated localized severe droughts in higher frequencies compared to moderate to severe low frequency droughts spread over wider areas in the basin. The approach can be used to develop improved drought indicators to assess the relationship between drought hazard and vulnerability and to enhance the performance of methods currently used for drought forecasting. In general, this preliminary investigation reveals that the western part of the basin will face a higher risk of drought when compared to other regions of the Limpopo Basin in terms of the medium-term drought patterns. The Limpopo Basin is water stressed and livelihood challenges remain high, thus impacts of droughts and related resilience options should be taken into account in the formulation of regional sustainable water resources development strategies.展开更多
The phenomenon of skewed sex ratios at birth has been reported in many ungulate species.So far,no consistent trend has emerged for roe deer(Capreolus capreolus),because male-biased,female-biased and equal sex ratios a...The phenomenon of skewed sex ratios at birth has been reported in many ungulate species.So far,no consistent trend has emerged for roe deer(Capreolus capreolus),because male-biased,female-biased and equal sex ratios at birth have all been found.Nevertheless,both the Trivers–Willard hypothesis and the theory of local resource competition have gained support.Despite the great number of studies carried out regarding the ecology of roe deer,too many aspects remain unclear,and contradictory results have been produced with respect to several crucial elements.Without further research,the discussion on which theory applies will therefore remain inconclusive.We put forward the argument that eventually the theories of Trivers–Willard and local resource competition can be considered as being not essentially different.After all,both theories explain the observed skewed sex ratios as being due to the effect of the progeny s sex on the mother s body condition and hence her reproductive success in subsequent years.Furthermore,neither theory is likely to prove to be suitable for roe deer,as several assumptions are unlikely to be met.In roe deer,skewed ratios probably only have a temporal character.As a matter of fact,several observations of skewed sex ratios in birds and mammals did not withstand the accumulation of further data,as sex ratios that were initially believed to be biased turned out to be equal in the long term.This is likely to be the case in roe deer as well.We hypothesize that roe deer,as r-strategists,will produce as many offspring as possible,regardless of sex.展开更多
文摘Waternet is the first water cycle company in the Netherlands, responsible for drinking water treatment and distribution, wastewater collection and treatment, and water system management and control in and around Amsterdam. Waternet started on 1 January 2006 to overcome the disadvantages of the rather fragmented organisation of the Dutch public water sector. The water cycle concept offers better opportunities to meet the future challenges in the water sector. The first four years of operation of Waternet show very promising results with respect to efficiency, customer orientation and quality improvement. To further develop the water cycle concept and to find sustainable solutions for the challenges the water sector is confronted with, Waternet focuses on six strategic innovation areas the coming years： water resources and water system; closing the water cycle; sustainability; new sanitation concepts; new products and services; management innovations.
基金the National Key Research and Development Program of China(2018YFE0204100).
文摘Many cities have pledged to achieve carbon neutrality.The urban water industry can also contribute its share to a carbon-neutral future.Using a multi-city time-series analysis approach,this study aims to assess the progress and lessons learned from the greenhouse gas(GHG)emissions management of urban water systems in four global cities:Amsterdam,Melbourne,New York City,and Tokyo.These cities are advanced in setting GHG emissions reduction targets and reporting GHG emissions in their water industries.All four cities have reduced the GHG emissions in their water industries,compared with those from more than a decade ago(i.e.,the latest three-year moving averages are 13%–32%lower),although the emissions have“rebounded”multiple times over the years.The emissions reductions were mainly due to various engineering opportunities such as solar and mini-hydro power generation,biogas valorization,sludge digestion and incineration optimization,and aeration system optimization.These cities have recognized the many challenges in reaching carbon-neutrality goals,which include fluctuating water demand and rainfall,more carbon-intensive flood-prevention and water-supply strategies,meeting new air and water quality standards,and revising GHG emissions accounting methods.This study has also shown that it is difficult for the water industry to achieve carbon neutrality on its own.A collaborative approach with other sectors is needed when aiming toward the city’s carbon-neutrality goal.Such an approach involves expanding the usual system boundary of the water industry to externally tap into both engineering and non-engineering opportunities.
文摘A spatial analysis of drought characteristics in the Limpopo basin is undertaken to evaluate its regional implications to water management challenges. In this study, drought duration, frequency and severity are investigated. In addition drought Severity-Area-Frequency (SAF) curves were constructed. The entire Limpopo River Basin is subdivided into four homogeneous regions based on topographic and climate variations in the basin, which was constructed with the K-Means Clustering algorithm. Using the medium range time series of the Standardized Precipitation Index (SPI) as an indicator of drought for each homogeneous region, monthly and annual SAF curves and maps of probability of drought occurrence were produced. The results indicated localized severe droughts in higher frequencies compared to moderate to severe low frequency droughts spread over wider areas in the basin. The approach can be used to develop improved drought indicators to assess the relationship between drought hazard and vulnerability and to enhance the performance of methods currently used for drought forecasting. In general, this preliminary investigation reveals that the western part of the basin will face a higher risk of drought when compared to other regions of the Limpopo Basin in terms of the medium-term drought patterns. The Limpopo Basin is water stressed and livelihood challenges remain high, thus impacts of droughts and related resilience options should be taken into account in the formulation of regional sustainable water resources development strategies.
文摘The phenomenon of skewed sex ratios at birth has been reported in many ungulate species.So far,no consistent trend has emerged for roe deer(Capreolus capreolus),because male-biased,female-biased and equal sex ratios at birth have all been found.Nevertheless,both the Trivers–Willard hypothesis and the theory of local resource competition have gained support.Despite the great number of studies carried out regarding the ecology of roe deer,too many aspects remain unclear,and contradictory results have been produced with respect to several crucial elements.Without further research,the discussion on which theory applies will therefore remain inconclusive.We put forward the argument that eventually the theories of Trivers–Willard and local resource competition can be considered as being not essentially different.After all,both theories explain the observed skewed sex ratios as being due to the effect of the progeny s sex on the mother s body condition and hence her reproductive success in subsequent years.Furthermore,neither theory is likely to prove to be suitable for roe deer,as several assumptions are unlikely to be met.In roe deer,skewed ratios probably only have a temporal character.As a matter of fact,several observations of skewed sex ratios in birds and mammals did not withstand the accumulation of further data,as sex ratios that were initially believed to be biased turned out to be equal in the long term.This is likely to be the case in roe deer as well.We hypothesize that roe deer,as r-strategists,will produce as many offspring as possible,regardless of sex.
