scholarly journals Human influences on streamflow drought characteristics in England and Wales

2017 ◽  
Author(s):  
Erik Tijdeman ◽  
Jamie Hannaford ◽  
Kerstin Stahl

Abstract. Human influences can affect streamflow drought characteristics and propagation. The question is where, when and why? To answer these questions, the impact of different human influences on streamflow droughts were assessed in England and Wales, across a broad range of climate and catchments conditions. We used a dataset consisting of catchments with near-natural flow as well as catchments for which different human influences have been indicated in the metadata ("Factors Affecting Runoff") of the UK National River Flow Archive (NRFA). A screening approach was applied on the streamflow records to identify human influenced records with drought characteristics that deviated from those found for catchments with near-natural flow. Three different deviations were considered, specifically deviations in: 1) the relationship between streamflow drought duration and the Base Flow Index; 2) the correlation between streamflow and precipitation and 3) the temporal occurrence of streamflow droughts compared to precipitation droughts, i.e., an increase or decrease in streamflow drought months relative to precipitation drought months over the period of record. The identified deviations were then related to the indicated human influences. Results showed that the majority of catchments for which human influences were indicated did not show streamflow drought characteristics that deviated from those expected under near-natural conditions. For the catchments that did show deviating streamflow drought characteristics, prolonged streamflow drought durations were found in some of the catchments affected by groundwater abstractions. Weaker correlations between streamflow and precipitation were found for some of the catchments with reservoirs, water transfers or groundwater augmentation schemes. An increase in streamflow drought occurrence towards the end of record was found for some of the catchments affected by groundwater abstractions and a decrease in streamflow drought occurrence for some of the catchments with either reservoirs or groundwater abstractions. In conclusion, the proposed screening approaches were successful in identifying streamflow records with deviating drought characteristics that are likely related to different human influences. However, a quantitative attribution of the impact of human influences on streamflow drought characteristics requires more detailed case by case information about the type and degree of all different human influences. Given that, in many countries, such information is often not readily accessible, the approach adopted here could provide useful in targeting future efforts. In England and Wales specifically, the catchments with deviating streamflow drought characteristics identified in this study could serve as the starting point of detailed case study research.

2018 ◽  
Vol 22 (2) ◽  
pp. 1051-1064 ◽  
Author(s):  
Erik Tijdeman ◽  
Jamie Hannaford ◽  
Kerstin Stahl

Abstract. Human influences can affect streamflow drought characteristics and propagation. The question is where, when and why? To answer these questions, the impact of different human influences on streamflow droughts were assessed in England and Wales, across a broad range of climate and catchments conditions. We used a dataset consisting of catchments with near-natural flow as well as catchments for which different human influences have been indicated in the metadata (“Factors Affecting Runoff”) of the UK National River Flow Archive (NRFA). A screening approach was applied on the streamflow records to identify human-influenced records with drought characteristics that deviated from those found for catchments with near-natural flow. Three different deviations were considered, specifically deviations in (1) the relationship between streamflow drought duration and the base flow index, BFI (specifically, BFIHOST, the BFI predicted from the hydrological properties of soils), (2) the correlation between streamflow and precipitation and (3) the temporal occurrence of streamflow droughts compared to precipitation droughts, i.e. an increase or decrease in streamflow drought months relative to precipitation drought months over the period of record. The identified deviations were then related to the indicated human influences. Results showed that the majority of catchments for which human influences were indicated did not show streamflow drought characteristics that deviated from those expected under near-natural conditions. For the catchments that did show deviating streamflow drought characteristics, prolonged streamflow drought durations were found in some of the catchments affected by groundwater abstractions. Weaker correlations between streamflow and precipitation were found for some of the catchments with reservoirs, water transfers or groundwater augmentation schemes. An increase in streamflow drought occurrence towards the end of their records was found for some of the catchments affected by groundwater abstractions and a decrease in streamflow drought occurrence for some of the catchments with either reservoirs or groundwater abstractions. In conclusion, the proposed screening approaches were sometimes successful in identifying streamflow records with deviating drought characteristics that are likely related to different human influences. However, a quantitative attribution of the impact of human influences on streamflow drought characteristics requires more detailed case-by-case information about the type and degree of all different human influences. Given that, in many countries, such information is often not readily accessible, the approaches adopted here could provide useful in targeting future efforts. In England and Wales specifically, the catchments with deviating streamflow drought characteristics identified in this study could serve as the starting point of detailed case study research.


Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 942 ◽  
Author(s):  
Hyeongsik Kang ◽  
Byungwoong Choi

This study presents the impact of natural flow patterns on downstream aquatic species habitats in a reach of the Geum River, Korea. The study reach is a 13.4 km long, located downstream of the Yongdam Dam. To assess such an impact, this study performed physical habitat simulations. The River2D model was used for the computation of the flow field and morphology, and the Habitat Suitability Index (HSI) model for the habitat simulation. Three habitat variables—flow depth, velocity, and substrate were used. The Zacco platypus and Baetis fuscatus were selected as the target fish and benthic macro-invertebrate, respectively. Using the building block approach (BBA), the scenarios for modifying dam operations were constructed in the study reach. Scenario 1, scenario 2, and scenario 3 were proposed by using the magnitude–duration concept, base flow allocation concept, and seasonally adjusted minimum flow allocation concept, respectively. Simulation results indicated that the scenarios’ effects significantly increased by about 14.3% for the weighted usable area (WUA). In addition, the morphology change with the restoration of flood events was investigated. It was revealed that the morphology change in the physical habitat simulations further increased by about 13% for the WUA. The change of dam operations through natural flow patterns is more advantageous to aquatic species.


Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 901 ◽  
Author(s):  
Laura Kelly ◽  
Robert M. Kalin ◽  
Douglas Bertram ◽  
Modesta Kanjaye ◽  
Macpherson Nkhata ◽  
...  

This study investigated how sporadic river datasets could be used to quantify temporal variations in the base flow index (BFI). The BFI represents the baseflow component of river flow which is often used as a proxy indicator for groundwater discharge to a river. The Bua catchment in Malawi was used as a case study, whereby the smoothed minima method was applied to river flow data from six gauges (ranging from 1953 to 2009) and the Mann-Kendall (MK) statistical test was used to identify trends in BFI. The results showed that baseflow plays an important role within the catchment. Average annual BFIs > 0.74 were found for gauges in the lower reaches of the catchment, in contrast to lower BFIs < 0.54 which were found for gauges in the higher reaches. Minimal difference between annual and wet season BFI was observed, however dry season BFI was >0.94 across all gauges indicating the importance of baseflow in maintaining any dry season flows. Long term trends were identified in the annual and wet season BFI, but no evidence of a trend was found in the dry season BFI. Sustainable management of the investigated catchment should, therefore, account for the temporal variations in baseflow, with special regard to water resources allocation within the region and consideration in future scheme appraisals aimed at developing water resources. Further, this demonstration of how to work with sporadic river data to investigate baseflow serves as an important example for other catchments faced with similar challenges.


2019 ◽  
Vol 488 (5) ◽  
pp. 539-544
Author(s):  
A. G. Georgiadi ◽  
N. I. Koronkevich ◽  
E. A. Barabanova ◽  
E. A. Kashutina ◽  
I. P. Milyukova

Changes of annual and seasonal flow of Volga, Don, Yenisei and Lena are estimated by two methods. One of them is to restore the natural flow of recent decades, during which there were observed its significant anthropogenic changes. For these purposes, we used data on the runoff of rivers (tributaries of the considered rivers and their upper parts), the water regime of which is relatively weakly changed by the anthropogenic impact. Another uses the data of water management statistics. Subsequently, the data on the naturalized river flow were compared with the anthropogenic-modified runoff for this and for the previous base period, when anthropogenic impact can be neglected. It is shown that climatic and anthropogenic factors perform either unidirectionally, increasing or decreasing the flow, or in opposite directions. Moreover, the impact of anthropogenic factors, mainly of reservoirs and water consumption, is of the same scale as the influence of climatic factors, while in many cases exceeds it.


2020 ◽  
Vol 1 (2) ◽  
pp. 74
Author(s):  
Dyah Indriana Kusumastuti

One of river flow components considered in watershed management is baseflow, the main contributor to the river flow during dry season. Ratio between baseflow to total flow is called Base Flow Index (BFI). In fact, BFI can be used as an indcator how good the catchment hydrology is. The purpose of this study is to analyze BFI of Way Seputih river at Hydrometry Station Buyut Udik. The method includes Recursive Digital Filter (RDF) method, which utilizes constant recession of hydrographs in displaying the ratio of baseflow from continuous discharge during periods when there is no direct runoff. Daily discharge data from Way Seputih river at Buyut Udik recorded from 1973 to 2006 is used. The result shows that yearly BFI values range from 0.142 to 0.487 and there is a decrease trend of yearly BFI over time. This result is confirmed by yearly average discharges which tend to decrease over time. These are effected by land cover degradation in Way Seputih catchment and  this should be a concern for authorities to improve land and water conservation in Way Seputih catchment so that river flow could be maintained throughout the year. Keywords: base flow index, baseflow, dry season 


2020 ◽  
Author(s):  
Daire Quinn ◽  
Conor Murphy ◽  
Robert L. Wilby ◽  
Tom Matthews ◽  
Ciaran Broderick ◽  
...  

&lt;p&gt;In this study we assess the seasonal hydrological forecast skill of river flow persistence across a sample of 46 catchments representative of Ireland&amp;#8217;s diverse range of hydrogeological conditions. This statistical approach is straightforward to implement as it uses a river&amp;#8217;s most recently observed flow anomaly (calculated over a predictor period of a given duration) as its forecasted flow anomaly (for a given horizon). In our hindcast experiment, persistence skill is evaluated against a streamflow climatology benchmark and by assessing the correlations between predicted and observed anomalies. Using the most skilful predictor period of 1-week, we find that the majority of persistence forecasts outperform the benchmark between April and September at the 1-month forecast horizon. However, this narrows to solely the summer months when using 2- and 3-month horizons.&amp;#160; Skill declines with increasing durations of the predictor and/ or forecast horizon period as a catchment is given more time to &amp;#8220;forget&amp;#8221; initial anomalous streamflow conditions and/or to be impacted by &amp;#8220;new&amp;#8221; anomalies. High rainfall events, for example, tend to disrupt the persistence of flows and greater forecast skill is thus found in the relatively drier months.&lt;/p&gt;&lt;p&gt;The degree of persistence skill is also strongly conditional on the &amp;#8220;memory&amp;#8221; inherent to each catchment (i.e. their storage capacity), as indicated by physical catchment descriptors such as the Base Flow Index (correlation &amp;#961; with skill = 0.86). Persistence skill is greatest in lowland regions characterised by permeable lithologies, well drained soils and lower annual average rainfall totals. Physical descriptors can thus be used to anticipate the likely performance of river flow persistence as a forecasting tool in rivers outside the catchment sample. Through multiple linear regression analysis, we identified the combination of predictors that produced the best-performing model (adjusted R&lt;sup&gt;2&lt;/sup&gt;= 0.89) and used it to predict the persistence forecast skill level expected in 215 catchments across the country at different horizons and seasons. Highlighting exactly when and where persistence provides higher predictive skill than the reference climatology forecast, we show the value of statistical flow persistence methods as a tougher-to-beat benchmark in the development of more sophisticated seasonal river flow forecasting methods at the catchment-scale. This research also underscores the scope for development of dynamical hydrological forecasting approaches in the wetter, poorly drained catchments underlain by impermeable lithologies, found mainly in the north-western and south-western regions of Ireland.&lt;/p&gt;


2014 ◽  
Vol 55 (1-2) ◽  
pp. 131-144
Author(s):  
Suzanne Marie Francis

By the time of his death in 1827, the image of Beethoven as we recognise him today was firmly fixed in the minds of his contemporaries, and the career of Liszt was beginning to flower into that of the virtuosic performer he would be recognised as by the end of the 1830s. By analysing the seminal artwork Liszt at the Piano of 1840 by Josef Danhauser, we can see how a seemingly unremarkable head-and-shoulders bust of Beethoven in fact holds the key to unlocking the layers of commentary on both Liszt and Beethoven beneath the surface of the image. Taking the analysis by Alessandra Comini as a starting point, this paper will look deeper into the subtle connections discernible between the protagonists of the picture. These reveal how the collective identities of the artist and his painted assembly contribute directly to Beethoven’s already iconic status within music history around 1840 and reflect the reception of Liszt at this time. Set against the background of Romanticism predominant in the social and cultural contexts of the mid 1800s, it becomes apparent that it is no longer enough to look at a picture of a composer or performer in isolation to understand its impact on the construction of an overall identity. Each image must be viewed in relation to those that preceded and came after it to gain the maximum benefit from what it can tell us.


2000 ◽  
Vol 151 (12) ◽  
pp. 502-507
Author(s):  
Christian Küchli

Are there any common patterns in the transition processes from traditional and more or less sustainable forest management to exploitative use, which can regularly be observed both in central Europe and in the countries of the South (e.g. India or Indonesia)? Attempts were made with a time-space-model to typify those force fields, in which traditional sustainable forest management is undermined and is then transformed into a modern type of sustainable forest management. Although it is unlikely that the history of the North will become the future of the South, the glimpse into the northern past offers a useful starting point for the understanding of the current situation in the South, which in turn could stimulate the debate on development. For instance, the patterns which stand behind the conflicts on forest use in the Himalayas are very similar to the conflicts in the Alps. In the same way, the impact of socio-economic changes on the environment – key word ‹globalisation› – is often much the same. To recognize comparable patterns can be very valuable because it can act as a stimulant for the search of political, legal and technical solutions adapted to a specific situation. For the global community the realization of the way political-economic alliances work at the head of the ‹globalisationwave›can only signify to carry on trying to find a common language and understanding at the negotiation tables. On the lee side of the destructive breaker it is necessary to conserve and care for what survived. As it was the case in Switzerland these forest islands could once become the germination points for the genesis of a cultural landscape, where close-to-nature managed forests will constitute an essential element.


Author(s):  
Daniel B. Kelly

This chapter analyzes how law and economics influences private law and how (new) private law is influencing law and economics. It focuses on three generation or “waves” within law and economics and how they approach private law. In the first generation, many scholars took the law as a starting point and attempted to use economic insights to explain, justify, or reform legal doctrines, institutions, and structures. In the second generation, the “law” at times became secondary, with more focus on theory and less focus on doctrines, institutions, and structures. But this generation also relied increasingly on empirical analysis. In the third generation, which includes scholars in the New Private Law (NPL), there has been a resurgence of interest in the law and legal institutions. To be sure, NPL scholars analyze the law using various approaches, with some more and some less predisposed to economic analysis. However, economic analysis will continue to be a major force on private law, including the New Private Law, for the foreseeable future. The chapter considers three foundational private law areas: property, contracts, and torts. For each area, it discusses the major ideas that economic analysis has contributed to private law, and surveys contributions of the NPL. The chapter also looks at the impact of law and economics on advanced private law areas, such as business associations, trusts and estates, and intellectual property.


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