pinecone/core-2020-05-10-deduplication huggingface dataset:
The importance of surface controls on overland flow connectivity in semi-arid environments : results from a numerical experimental approach.

In semi-arid environments, the characteristics of the land surface determine how rainfall is transformed into surface runoff and influences how this runoff moves from the hillslopes into river channels. Whether or not water reaches the river channel is determined by the hydrological connectivity. This paper uses a numerical experiment-based approach to systematically assess the effects of slope length, gradient, flow path convergence, infiltration rates and vegetation patterns on the generation and connectivity of runoff. The experiments were performed with the Connectivity of Runoff Model, 2D version distributed, physically based, hydrological model. The experiments presented are set within a semi-arid environment, characteristic of south-eastern Spain, which is subject to low frequency high rainfall intensity storm events. As a result, the dominant hydrological processes are infiltration excess runoff generation and surface flow dynamics. The results from the modelling experiments demonstrate that three surface factors are important in determining the form of the discharge hydrograph: the slope length, the slope gradient and the infiltration characteristics at the hillslope-channel connection. These factors are all related to the time required for generated runoff to reach an efficient flow channel, because once in this channel, the transmission losses significantly decrease. Because these factors are distributed across the landscape, they have a fundamental role in controlling the landscape hydrological response to storm events
Regime theories in gravel-bed rivers: Models, controlling variables, and applications in disturbed Italian rivers

Downstream hydraulic geometry relationships describe the shape of alluvial channels in terms of bankfull width, flow depth,\ud
flow velocity, and channel slope. Recent investigations have stressed the difference in spatial scales associated with these\ud
variables and thus the time span required for their adjustment after a disturbance. The aim of this study is to explore the\ud
consequences in regime models considering the hypothesis that while channel width and depth adjust quickly to changes in water\ud
and sediment supply, reach slope requires a longer time span. Three theoretical models were applied. One model incorporates an\ud
extremal hypothesis (Millar RG. 2005. Theoretical regime equations for mobile gravel-bed rivers with stable banks.\ud
Geomorphology 64: 207–220), and the other two are fully physically based (Ikeda S, Parker G, Kimura Y. 1988. Stable width\ud
and depth of straight gravel rivers with heterogeneous bed materials. Water Resources Research 24: 713–722; Parker G, Wilcock\ud
PR, Paola C, Dietrich W, Pitlick J. 2007. Physical basis for quasi universal relations describing bankfull hydraulic geometry of\ud
single-thread gravel-bed rivers. Journal of Geophysical Research 112, DOI: 10.1029/2006JF000549). In order to evaluate the\ud
performance of models introducing the slope as an independent variable, we propose two modifications to previous models.\ud
The performance of regime models was tested against published data from 142 river reaches and new hydraulic geometry data\ud
from gravel-bed rivers in Patagonia (Argentina) and north-eastern Italy.\ud
Models that assume slope as a control (Ikeda et al., 1988; or Millar, 2005) predict channel depth and width reasonably well.\ud
Parker et al.’s (2007) model improved predictions because it filters the scatter in slope data with a relation slope–discharge. The\ud
extremal hypothesis model of Millar (2005) predicts comparably to the other physically based models.\ud
Millar’s model was chosen to describe the recent changes in the Piave and Brenta rivers due to human intervention – mainly\ud
in-channel gravel mining. The change in sediment supply and recovery was estimated for these rivers. This study supports the\ud
interpretation that sediment supply is the key factor guiding morphological changes in these rivers
High-frequency precipitation and stream water quality time\ud
series from Plynlimon, Wales: an openly accessible data\ud
resource spanning the periodic table

This scientific briefing announces the availability of a new multi-element highfrequency water quality data set that is openly accessible to the research community. The data set comprises up to 2 years of 7-hourly water quality data for two streams and one rainfall site in the Upper Severn catchment at Plynlimon in Mid-Wales. The measurements cover 50 analytes ranging from H+ to U and spanning six orders of magnitude in concentration, including major, minor and trace elements as well as nutrients, and they complement decades of weekly measurements of the same analytes at the Upper Severn. Together, the weekly and 7-hourly time series provide a unique data set for studying both long-term trends and short-term dynamics. The data show complex behaviour over a wide range of timescales, challenging our understanding of catchment processes and informing future modelling efforts
Inferring air-water temperature relationships from river and catchment properties

This is the accepted version of the following article: JOHNSON, M.F., WILBY, R.L. and TOONE, J.A., 2014. Inferring air-water temperature relationships from river and catchment properties. Hydrological Processes, 28 (6), pp. 2912 - 2928 which has been published in final form at: http://dx.doi.org/10.1002/hyp.9842Water temperature (Tw) is a key determinant of freshwater ecosystem status and cause for concern under a changing climate. Hence, there is growing interest in the feasibility of moderating rising Tw through management of riparian shade. The Loughborough University Temperature Network (LUTEN) is an array of 36 water and air temperature (Ta) monitoring sites in the English Peak District set-up to explore the predictability of local Tw, given Ta, river reach, and catchment properties. Year 1 of monitoring shows that 84%-94% of variance in daily Tw is explained by Ta. However, site-specific logistic regression parameters exhibit marked variation and dependency on upstream riparian shade. Perennial spring flows in the lower River Dove also affect regression model parameters and strongly buffer daily and seasonal mean Tw. The asymptote of the models (i.e. maximum expected Tw) is particularly sensitive to groundwater inputs. We conclude that reaches with spring flows potentially offer important thermal refuges for aquatic organisms against expected long-term warming of rivers and should be afforded special protection. © 2013 John Wiley & Sons, Ltd
The chronology and hydrometeorology of catastrophic floods on Dartmoor, South West England

Foulds, S. A., Macklin, M., Brewer, P. (2014). The chronology and hydrometeorology of catastrophic floods on Dartmoor, South West England. Hydrological Processes, 28 (7), 3067-3087Extreme floods are the most widespread and often the most fatal type of natural hazard experienced in Europe, particularly in upland and mountainous areas. These ?flash flood? type events are particularly dangerous because extreme rainfall totals in a short space of time can lead to very high flow velocities and little or no time for flood warning. Given the danger posed by extreme floods, there are concerns that catastrophic hydrometeorological events could become more frequent in a warming world. However, analysis of longer term flood frequency is often limited by the use of short instrumental flow records (last 30?40?years) that do not adequately cover alternating flood-rich and flood-poor periods over the last 2 to 3 centuries. In contrast, this research extends the upland flood series of South West England (Dartmoor) back to ca AD 1800 using lichenometry. Results show that the period 1820 to mid-1940s was characterized by widespread flooding, with particularly large and frequent events in the mid-to-late 19th and early 20th centuries. Since ca 1850 to 1900, there has been a general decline in flood magnitude that was particularly marked after the 1930s/mid-1940s. Local meteorological records show that: (1) historical flood-rich periods on Dartmoor were associated with high annual, seasonal and daily rainfall totals in the last quarter of the 19th century and between 1910 and 1946, related to sub-decadal variability of the North Atlantic Oscillation and receipt of cyclonic and southerly weather types over the southwest peninsula; and (2) the incidence of heavy daily rainfall declined notably after 1946, similar to sedimentary archives of flooding. The peak period of flooding on Dartmoor predates the beginning of gauged flow records, which has practical implications for understanding and managing flood risk on rivers that drain Dartmoor.authorsversionPeer reviewe
Evidence for extreme variations in the permeability of laterite from a detailed analysis of well behaviour in Nigeria

Laterite soils are widespread in tropical Africa and have a large impact on the hydrology of the areas they cover. The permeability of laterite helps determine the partitioning of runoff and interflow and regulates groundwater recharge to underlying bedrock. Groundwater within laterite also forms a widespread source of drinking water, typically from unimproved hang-dug-wells. Despite its importance, there is little published information on laterite aquifer properties. In this study, data from a 6 m deep well in Nigeria have been analysed to characterise the hydraulic conductivity of the laterite from repeated pumping tests. Transmissivity measurements from 40 tests spread out across a hydrological year varied from 0.1 to 1000 m2/d. Further interpretation of the data demonstrate a strong non-linear decrease in horizontal hydraulic conductivity with depth, characterised by an upper horizon of extreme permeability (400 m/d), and a much lower permeability profile beneath (<0.1 m/d). These data are substantiated with observations from other wells throughout the area. This non-linear permeability structure has several implications: the upper laterite can facilitate rapid lateral throughflow in the wet season, enabling contaminants to be transported significant distances (up to 1 km); natural groundwater levels are restricted to a narrow range for much of the year; and, in the dry season, the lower permeability of the deeper laterite restricts the amount of water which can be abstracted from shallow wells, leading to well failure. The work highlights the need for a wider study to better understand laterite soils and the role they play in regional hydrology
Hydrological modelling using data from monthly GCMs in a regional catchment

This study demonstrates the use of spatially downscaled, monthly general circulation model (GCM) rainfall and temperature data to drive the established HyMOD hydrological model to evaluate the prospective effects of climate change on the fluvial run-off of the River Derwent basin in the UK. The evaluation results of this monthly hydrological model using readily available, monthly GCM data are consistent with studies on nearby catchments employing high-temporal resolution data, indicating that useful hydro-climatic planning studies may be possible using standard datasets and modest computational resources. HyMOD was calibrated against 5 km2 gridded UK Climate Projections dataset data and then driven using monthly spatially interpolated (~5 km2) outputs from Hadley Centre Coupled Model, version 3 and the Canadian Centre for Climate Modelling and Analysis for Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC-SRES) A2a and B2a covering the 2020s, 2050s and 2080s. Results for both GCMs project a decrease in annual run-off in both GCM models and scenarios with higher values in the summer/autumn months, whereas an increase in the later winter months. Both Hadley Centre Coupled Model, version 3 and the Canadian Centre for Climate Modelling and Analysis show higher ranges of uncertainty during the winter season with higher values of run-off associated with December in all three simulation periods and two scenarios. A seasonal comparison of run-off simulations shows that both GCMs give similar results in summer and autumn, whereas disparities due to GCM uncertainties are more conspicuous in winter and spring. In this study, both the GCMs under A2a scenario have demonstrated the high possibility of time shift in monthly average peak run-offs in the Derwent River by 2080s in comparison with the early 21st century
Modeling of non-point source nitrogen pollution from 1979 to 2008 in Jiaodong Peninsula, China

Efforts to reduce land-based non-point source (NPS) pollutions from watersheds to coastal waters are ongoing all around the world. In this study, annual yield of NPS nitrogen (NPS-N) pollution in Jiaodong Peninsula, China from 1979 to 2008 was estimated. The results showed that: from 1979 to 2008, NPS-N yields exhibited significant inter-annual variations and an increasing trend on decadal scale. High NPS-N yield was mainly found in east and south parts, as well as the urbanized coastal regions in Jiaodong Peninsula. Among the 32 river basins, the three largest basins yielded more than 41.16% of the NPS-N. However, some small coastal watersheds along the South Yellow Sea and Jiaozhou Bay had higher per unit area yield. Most of the small watersheds characterized by seasonal runoff had coastal waters pertain to mild and moderate pollution levels. The ratio of watershed area to shoreline length and the up-stream land use had significant impacts on NPS-N flux through the shoreline. Among the four adjacent coastal areas of Jiaodong Peninsula, Jiaozhou Bay was the most noteworthy one not only because of high levels of land-based NPS-N pollution but also because of its nearly enclosed structure. The combination between integrated coastal zone management and integrated river basin management, land use planning and landscape designing in Jiaodong Peninsula is recommended. Copyright (c) 2013 John Wiley & Sons, Ltd.Efforts to reduce land-based non-point source (NPS) pollutions from watersheds to coastal waters are ongoing all around the world. In this study, annual yield of NPS nitrogen (NPS-N) pollution in Jiaodong Peninsula, China from 1979 to 2008 was estimated. The results showed that: from 1979 to 2008, NPS-N yields exhibited significant inter-annual variations and an increasing trend on decadal scale. High NPS-N yield was mainly found in east and south parts, as well as the urbanized coastal regions in Jiaodong Peninsula. Among the 32 river basins, the three largest basins yielded more than 41.16% of the NPS-N. However, some small coastal watersheds along the South Yellow Sea and Jiaozhou Bay had higher per unit area yield. Most of the small watersheds characterized by seasonal runoff had coastal waters pertain to mild and moderate pollution levels. The ratio of watershed area to shoreline length and the up-stream land use had significant impacts on NPS-N flux through the shoreline. Among the four adjacent coastal areas of Jiaodong Peninsula, Jiaozhou Bay was the most noteworthy one not only because of high levels of land-based NPS-N pollution but also because of its nearly enclosed structure. The combination between integrated coastal zone management and integrated river basin management, land use planning and landscape designing in Jiaodong Peninsula is recommended. Copyright (c) 2013 John Wiley & Sons, Ltd
Spatial and temporal variability of groundwater dynamics in a sub-Mediterranean mountain catchment

37 páginas, 10 figuras, 2 tablas.- The definitive version is available at: http://onlinelibrary.wiley.com/doi/10.1002/hyp.9892/pdf[EN] The temporal and spatial dynamics of groundwater was investigated in a small catchment in the Spanish Pyrenees, which was\ud
extensively used for agriculture in the past. Analysis of the water tableﬂuctuations atﬁve locations over a 6-year period demonstrated\ud
that the groundwater dynamics had a marked seasonal cycle involving a wetting-up period that commenced with the ﬁrst autumn\ud
rainfall events, a saturation period during winter and spring and a drying-down period from the end of spring until the end of the\ud
summer. The length of the saturation period showed great interannual variability, which was mainly inﬂuenced by the rainfall and\ud
evapotranspiration characteristics. There was marked spatial variability in the water table, especially during the wetting-up period,\ud
which could be related to differences in slope and drainage area, geomorphology, soil properties and local topography. Areas\ud
contributing to runoff generation were identiﬁed within the catchment byﬁeld mapping of moisture conditions. Areas contributing to\ud
inﬁltration excess runoff were correlated with former cultivated ﬁelds affected by severe sheetwash erosion. Areas contributing to\ud
saturation excess runoff were characterized by a marked spatial dynamics associated with catchment wetness conditions. The\ud
saturation spatial pattern, which was partially related to the topographic index, was very patchy throughout the catchment, suggesting\ud
the inﬂuence of other factors associated with past agricultural activities, including changes in local topography and soil properties. The\ud
relationship between water table levels and streamﬂow was weak, especially during the wetting-up period, suggesting little connection\ud
between ground water and the hydrological response, at least at some locations. The results suggest that in drier and human-disturbed\ud
environments, such as sub-Mediterranean mountains, saturation patterns cannot be represented only by the general topography of the\ud
catchment. They also suggest that groundwater storage and runoff is not a succession of steady-state ﬂow conditions, as assumed in\ud
most hydrological models. Copyright © 2013 John Wiley & Sons, Ltd.This research was conducted with the support of INDICA\ud
(CGL2011-27753-C02, C01) and RespHiMed\ud
(CGL2010-18374) projects, funded by the Spanish\ud
Ministry of Sciences and Innovation, and RESEL,\ud
ﬁnanced by the Spanish Ministry of the Environment.\ud
N. Lana-Renault and J. Latron were the recipients of\ud
research contracts (Juan de la Cierva, and Ramón y Cajal\ud
programme, respectively) funded by the Spanish Ministry\ud
of Sciences and Innovation. Support provided by E.\ud
Nadal-Romero and M.L. Rodríguez Blanco during\ud
ﬁeldwork is acknowledged.Peer reviewe
A goodness of fit measure related to r² for model performance assessment

Checking the predictive worth of an environmental model inevitably includes a goodness of fit metric to quantify the degree of matching to recorded data, thereby giving a measure of model performance. Considerable analysis and discussion have taken place over fit indices in hydrology, but a neglected aspect is the degree of communicability to other disciplines. It is suggested that a fit index is best communicated to colleagues via reference to models giving unbiased predictions, because unbiased environmental models are a desirable goal across disciplines. That is, broad recognition of a fit index is aided if it simplifies in the unbiased case to a familiar and logical expression. This does not hold for the Nash–Sutcliffe Efficiency E which reduces to the somewhat awkward unbiased expression E = 2 – 1/r², where r² is the coefficient of determination. A new goodness of fit index V is proposed for model validation as V =  r²/(2-E), which simplifies to the easily communicated V = r4 in the unbiased case. The index is defined over the range 0 ≤ V ≤ 1, and it happens that V < E for larger values of E. Some synthetic and recorded data sets are used to illustrate characteristics of V in comparison to
Past and future changes in frost day indices in Catskill Mountain region of New York

Changes in frost indices in the New York's Catskill Mountains region, the location of water supply reservoirs for New York City, have potentially important implications. Frost day is defined as a day with T[subscript min] < 0 °C. The objective of this study was to investigate past and predicted changes in minimum temperature (T[subscript min]) and six frost indices in the Catskill Mountains covering six reservoir watersheds. Studied frost indices included (1) number of frost days, (2) number of months with frost, (3) last spring freeze date (LSF), (4) first fall freeze date (FFF), (5) growing season length (GSL), and (6) frost season length. Past changes in the frost indices were studied using observed daily T[subscript min] for each watershed for the periods 1960–2008. Future changes in frost indices for the periods (2045–2065 and 2080–2100) were studied for emission scenarios (A1B, A2, and B1) downscaled from global climate models GCMs). Results indicated a general increase in average Tmin and GSL and a decrease in number of frost days, months with frost, frost season length, earlier LSF, and later FFF from the historical to the future periods, and the magnitude of change varied among the watersheds and GCMs. For the period 1960–2000, in all watersheds (except Cannonsville), LSF occurred earlier by 2.6–4.3 days/decade, FFF occurred later by 2.7–3.2 day/decade, and GSL was longer by 2.4–4 day/decade. Among the scenarios and GCMs, LSF occurred earlier by 4–11 and 4.5–15 days/decade for the periods 2045–2065 and 2081–2100, respectively; FFF occurred later by 1–10 and 4–13 days/decade for the periods 2045–2065 and 2081–2100, respectively; and GSL was longer by 10–25 and 13–40 days/decade for the periods 2045–2065 and 2081–2100, respectively. The increase in GSL is expected to affect hydrologic, ecosystem, and biogeochemical processes with increased net primary productivity and a resulting increase in total annual evapotranspiration
Combining two filter paper-based analytical methods to monitor temporal variations in the geochemical properties of fluvial suspended particulate matter

Many of the commonly used analytical techniques for assessing the properties of fluvial suspended particulate matter (SPM) are neither cost effective nor time efficient, making them prohibitive to long-term high-resolution monitoring. We present an in-depth methodology utilizing two types of spectroscopy which, when combined with automatic water samplers, can generate accurate, high-temporal resolution SPM geochemistry data, inexpensively and semi-destructively, directly from sediment covered filter papers. A combined X-ray fluorescence spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy approach is developed to estimate concentrations for a range of elements (Al, Ca, Ce, Fe, K, Mg, Mn, Na, P, Si, Ti) and compounds (organic carbon, Aldithionate, Aloxalate, Fedithionate, and Feoxalate) within SPM trapped on quartz fibre filters at masses as low as 3 mg. Calibration models with small prediction errors are derived, along with mass correction factor models to account for variations in retained SPM mass. Spectral pre-processing methods are shown to enhance the reproducibility of results for some compounds, and the importance of filter paper selection and homogeneous sample preparation in minimizing spectral interference is emphasized. The geochemical signal from sediment covered filter papers is demonstrated to be time stable enabling samples to be stored for several weeks prior to analysis. Example results obtained during a heavy precipitation event in October 2012 demonstrate the methodology presented here has considerable potential to be utilized for high-resolution monitoring of SPM geochemistry under a range of in-stream hydrological condition