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1
Han, S., D. Xu, and S. Wang. "Runoff formation from plot, field, to small catchment with shallow groundwater table and dense drainage system in agricultural North Huaihe River Plain, China." Hydrology and Earth System Sciences Discussions 9, no. 4 (April 2, 2012): 4235–62. http://dx.doi.org/10.5194/hessd-9-4235-2012.
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Abstract. Runoff formation processes at the experimental plot (1600 m2), the field (0.06 km2), and the small catchment (1.36 km2) with shallow groundwater table and dense drainage system in North Huaihe River Plain (the northern part of the Huaihe River Basin, China) were analyzed based on observed rainfall, runoff and groundwater table depth data of 30 storm events during the flood seasons from 1997 to 2008. At the outlet of the furrow of the experimental plot, only the surface runoff was collected and measured, whereas both the surface and subsurface runoffs were collected at the drainage ditches outlets of the field and the small catchment. The present study showed that the relatively narrow range of rainfall amounts resulted in significantly different runoff amounts at all the three scales. When the ground water is close to surface, the runoff amount is a great percentage of rainfall amount. Significant linear relationships between the difference of rainfall and runoff amounts and the changes in water table or the initial water table depth were found. When the 30 events were divided into three groups with initial water table (as a parameter indicating the antecedent moisture condition) shallower than 0.5 m, deeper than 2.3 m or between 0.5 m and 2.3 m, significant rainfall-runoff relationships existed for each group. These imply that saturation-excess surface flow dominated the runoff response, especially when water table is shallow. For almost all the events, the water table rose above the bottom of drainage ditch during the event, and the total runoff amounts were larger at the field and the catchment than that at the plot with only surface flow measured, showing a great contribution of subsurface flow. Groundwater table depth, not only reflecting the antecedent moisture conditions, but also influencing the lateral sub-surface flow to the drainage ditches, would be an important parameter dominating runoff formation process in catchment like the study area with shallow water table and dense drainage system.
2
Maršálek, J., and D. Sztruhár. "Urban Drainage: Review of Contemporary Approaches." Water Science and Technology 29, no. 1-2 (January 1, 1994): 1–10. http://dx.doi.org/10.2166/wst.1994.0645.
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Recent developments in urban storm drainage are reviewed starting with rainfall/runoff processes, followed by discussions of combined sewage, drainage impacts on receiving waters, impact mitigation, hydroinformatics, regulatory programs and conclusions. The most promising trends in this field include improvements in spatial definition of rainfall data, runoff modelling with a limited number of model parameters and recognition of modelling uncertainties, analytical statistical modelling of runoff quality, advances in the understanding and modelling of sewer sediment transport, the use of biomonitoring and modelling in assessing drainage impacts on receiving waters, further refinement of best management practices for stormwater management, development of new processes for treatment of stormwater, experience with vortex combined sewer overflow structures and their applications in combination with other treatment devices, real time control of sewer system operation, advances in hydroinformatics leading to improvements in the integrated management and modelling of drainage systems, interfacing of drainage models with geographic information systems, and improved regulation of drainage effluents.
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Yu, Yanmei, Junzeng Xu, Pingcang Zhang, Yan Meng, and Yujiang Xiong. "Controlled Irrigation and Drainage Reduce Rainfall Runoff and Nitrogen Loss in Paddy Fields." International Journal of Environmental Research and Public Health 18, no. 7 (March 24, 2021): 3348. http://dx.doi.org/10.3390/ijerph18073348.
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In southern China, the growing period of rice is synchronized with the rainy period, and the loss of nutrients (such as nitrogen) due to unreasonable irrigation and drainage, along with rainfall and runoff, has become the main source of agricultural nonpoint source pollution. The laws of runoff and nitrogen loss in paddy fields under different irrigation and drainage modes are not clear. In this study, field experiments were adopted to observe the runoff and nitrogen loss under typical rainfall and throughout the whole growth period. The results showed that, compared with the traditional irrigation and drainage mode, the controlled irrigation and drainage mode reduced the drainage of two typical rainfall processes by 47.5% and 31.3% and the peak drainage by 38.9% and 14.4%. Compared with those under the traditional irrigation and drainage mode, the average concentrations of total nitrogen, nitrate nitrogen, and ammonium nitrogen under the controlled irrigation and drainage mode were reduced by 22.2%, 22.7%, and 27.8%, respectively, during the whole rainfall process on July 21 and were decreased by 27.1%, 11.4%, and 25.6%, respectively, on August 25. In irrigated rice areas, under the controlled irrigation and drainage mode, drainage was reduced after two intercepts through paddy fields and drainage ditches. The nitrogen concentration in the drainage ditch decreased due to the increase in retention time and the effect of the ditch and field wetland. Compared with the traditional irrigation and drainage mode, the total nitrogen, nitrate nitrogen, and ammonium nitrogen loads of the controlled irrigation and drainage mode were reduced by 69.8%, 65.3%, and 69.7%, respectively.
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Hagen, Jon Ove, Bernd Etzelmüller, and Anne-Marie Nuttall. "Runoff and drainage pattern derived from digital elevation models, Finsterwalderbreen, Svalbard." Annals of Glaciology 31 (2000): 147–52. http://dx.doi.org/10.3189/172756400781819879.
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AbstractFinsterwalderbreen (77°26’ N, 15° 15’ E) is a 35 km2 polythermal, surge-type glacier in southern Spitsbergen, Svalbard. Extensive field investigations have been carried out on the glacier, including mapping of bed topography by radio-echo soundings, mass-balance measurements and hydrological and meteorological registrations. In this paper we have used surface and bed topography and observations of summer ablation to estimate total runoff and subglacial drainage pattern by means of spatial map analysis in standard geographic information system software. The location and relative importance of the water-channel outlets from the glacier were estimated, as well as the change in drainage pattern over the period 1970–90. The results could be compared to direct observations of drainage pattern and discharge recordings. The analyses indicate that the location of the subglacial channels is dominated by the surface topography and thus that the channels are partly pressurized.
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Schärer, Lotte Askeland, Jan Ove Busklein, Edvard Sivertsen, and Tone M. Muthanna. "Limitations in using runoff coefficients for green and gray roof design." Hydrology Research 51, no. 2 (March 30, 2020): 339–50. http://dx.doi.org/10.2166/nh.2020.049.
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Abstract Climate change combined with urbanization increases the performance demand on urban drainage systems. Green roofs are one of the most used green infrastructure measures to alleviate the pressure on the urban drainage system through the detention and retention of runoff. The rational method with the runoff coefficient (C) is one of the most commonly used design tools for stormwater design in Norway. This method relies on a runoff coefficient being available for green roofs, which is typically not the case. This paper compares laboratory and experimental field studies to investigate runoff coefficients from different types of detention-based roofs. The methodology described in the German ‘FLL Guideline’, one of the world's most commonly used green roof standards, was used to measure the runoff coefficients for the different components making up a typical green roof. The contribution from each layer is reflected in the runoff coefficients. The runoff coefficients from the field experiments were calculated using observed precipitation and runoff from existing green roofs in Oslo, Trondheim, Sandnes, and Bergen, Norway. Events that had a cumulative precipitation comparable to the laboratory events, but longer durations, were selected. These events gave significantly lower and varying runoff coefficients, clearly demonstrating the limitation of choosing a suitable runoff coefficient for a given roof. However, laboratory experiments are important in understanding the underlying flow processes in the different layers in a detention-based roof.
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Hadadin, N. "Spatial stochastic and analytical approaches to describe the complex hydraulic variability inherent channel geometry." Hydrology and Earth System Sciences Discussions 8, no. 4 (July 19, 2011): 6967–92. http://dx.doi.org/10.5194/hessd-8-6967-2011.
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Abstract. The effects of basin hydrology on channel hydraulic variability for incised streams were investigated using available field data sets and models of watershed hydrology and channel hydraulics for Yazoo River Basin, USA. The study presents the hydraulic relations of bankfull discharge, channel width, mean depth, cross- sectional area, longitudinal slope, unit stream power, and runoff production as a function of drainage area using simple linear regression. The hydraulic geometry relations were developed for sixty one streams, twenty of them are classified as channel evaluation model (CEM) Types IV and V and forty one of them are streams of CEM Types II and III. These relationships are invaluable to hydraulic and water resources engineers, hydrologists, and geomorphologists, involved in stream restoration and protection. These relations can be used to assist in field identification of bankfull stage and stream dimension in un-gauged watersheds as well as estimation of the comparative stability of a stream channel. Results of this research show good fit of hydraulic geometry relationships in the Yazoo River Basin. The relations indicate that bankfull discharge, channel width, mean depth, cross-sectional area have stronger correlation to changes in drainage area than the longitudinal slope, unit stream power, and runoff production for streams CEM Types II and III. The hydraulic geometry relations show that runoff production, bankfull discharge, cross-sectional area, and unit stream power are much more responsive to changes in drainage area than are channel width, mean depth, and slope for streams of CEM Types IV and V. Also, the relations show that bankfull discharge and cross-sectional area are more responsive to changes in drainage area than are other hydraulic variables for streams of CEM Types II and III. The greater the regression slope, the more responsive to changes in drainage area will be.
7
Silburn, DM, and DM Freebairn. "Evaluations of the CREAMS model. III. Simulation of the hydrology of vertisols." Soil Research 30, no. 5 (1992): 547. http://dx.doi.org/10.1071/sr9920547.
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The CREAMS hydrology model was evaluated for two Vertisols, each with three fallow management strategies, by comparing predictions of runoff, soil moisture and drainage with 5-8 years of measured data. Model parameter values were derived by: (i) using a combination of measured site characteristics and published values, and (ii) optimizing selected parameters, particularly the runoff parameter (curve number). With parameter values from published sources, runoff was overpredicted by 1 to 39%; good estimates of total soil moisture were obtained. Using optimized curve numbers, runoff was predicted well (daily, r2 = 0.83; monthly, r2 = 0.92; annual, r2 = 0.94). Total soil moisture values were predicted well, the main source of error being from overprediction of transpiration. Errors in predicted runoff caused little of the error in predicted total soil moisture. The distribution of soil moisture in the soil was poorly predicted. Drainage predictions were similar to estimates from steady-state solute mass balance. Optimized curve numbers derived in this study provide parameter values for modelling the water balance of self-mulching Vertisols. Values of other model parameters, derived from field measurements and published sources were near optimal, and predictions were not improved by adjusting the more sensitive of these parameters. The model is considered adequate for many practical applications. Some enhancements to the model are suggested.
8
Ruan, Mingchaun, and Jan B. M. Wiggers. "Application of time-series analysis to urban storm drainage." Water Science and Technology 36, no. 5 (September 1, 1997): 125–31. http://dx.doi.org/10.2166/wst.1997.0180.
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In urban storm drainage, deterministic models, such as SWMM, HydroWorks and MOUSE are commonly used. However, comprehensive research programmes, including field surveys, have indicated that most processes related to urban storm drainage have stochastic characteristic, like the occurrence of rainfall events, the processes of rainfall-runoff and flow routing in sewer networks3etc.. Particularly, sediments found in sewers either in suspension or in deposition, cannot be considered as having a unique entity. Inhomogeneity and randomness are just the nature of sewer sediment behaviour. Most data required for urban storm drainage are time-series data, such as rainfall intensity, water level measured in an outfall, CSO discharge and pollutant load etc.. Consequently, time-series analysis should be an alternative for predicting some relationships of urban storm drainage, such as (net) rainfall-CSO discharge, rainfall-water level and CSO discharge-pollutant load.
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Rammal, Mohamad, and Emmanuel Berthier. "Runoff Losses on Urban Surfaces during Frequent Rainfall Events: A Review of Observations and Modeling Attempts." Water 12, no. 10 (October 6, 2020): 2777. http://dx.doi.org/10.3390/w12102777.
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Quantifying urban runoff during frequent rainfall events is a key element in quality management of urban water due to their high contribution to the annual runoff flow. This explains the growing interest among hydrologists in studying runoff flow on urban surfaces. In this paper, we review most of the experimental approaches as well as the modeling ones conducted in the literature to understand and estimate runoff flow on urban areas. This review highlights the incoherence between our current understanding of the hydrological behavior of urban areas during frequent events and our conception of the loss functions in the urban drainage models. Field studies provided more insight into the determinant processes occurring on the different surface types during frequent events with depression storage being a fundamental element varying between surface types and for the same surface type and infiltration process being relatively important on paved areas especially in their cracks that constitute preferential pathways for rainwater. Analyzing a wide range of urban drainage models showed that these elements along with the temporal evolution of the hydrological behavior of urban surfaces due to seasonal and state conditions are not fully integrated in the models’ structures, which were initially developed for heavy rainfall events. Adapting the assumptions of urban drainage models based on these new factors must improve the performance of hydrological models for frequent rainfall events.
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Guo, Tian, Margaret Gitau, Venkatesh Merwade, Jeffrey Arnold, Raghavan Srinivasan, Michael Hirschi, and Bernard Engel. "Comparison of performance of tile drainage routines in SWAT 2009 and 2012 in an extensively tile-drained watershed in the Midwest." Hydrology and Earth System Sciences 22, no. 1 (January 8, 2018): 89–110. http://dx.doi.org/10.5194/hess-22-89-2018.
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Abstract. Subsurface tile drainage systems are widely used in agricultural watersheds in the Midwestern US and enable the Midwest area to become highly productive agricultural lands, but can also create environmental problems, for example nitrate-N contamination associated with drainage waters. The Soil and Water Assessment Tool (SWAT) has been used to model watersheds with tile drainage. SWAT2012 revisions 615 and 645 provide new tile drainage routines. However, few studies have used these revisions to study tile drainage impacts at both field and watershed scales. Moreover, SWAT2012 revision 645 improved the soil moisture based curve number calculation method, which has not been fully tested. This study used long-term (1991–2003) field site and river station data from the Little Vermilion River (LVR) watershed to evaluate performance of tile drainage routines in SWAT2009 revision 528 (the old routine) and SWAT2012 revisions 615 and 645 (the new routine). Both the old and new routines provided reasonable but unsatisfactory (NSE < 0.5) uncalibrated flow and nitrate loss results for a mildly sloped watershed with low runoff. The calibrated monthly tile flow, surface flow, nitrate-N in tile and surface flow, sediment and annual corn and soybean yield results from SWAT with the old and new tile drainage routines were compared with observed values. Generally, the new routine provided acceptable simulated tile flow (NSE = 0.48–0.65) and nitrate in tile flow (NSE = 0.48–0.68) for field sites with random pattern tile and constant tile spacing, while the old routine simulated tile flow and nitrate in tile flow results for the field site with constant tile spacing were unacceptable (NSE = 0.00–0.32 and −0.29–0.06, respectively). The new modified curve number calculation method in revision 645 (NSE = 0.50–0.81) better simulated surface runoff than revision 615 (NSE = −0.11–0.49). The calibration provided reasonable parameter sets for the old and new routines in the LVR watershed, and the validation results showed that the new routine has the potential to accurately simulate hydrologic processes in mildly sloped watersheds.
11
Ballard, C. E., N. McIntyre, and H. S. Wheater. "Effects of peatland drainage management on peak flows." Hydrology and Earth System Sciences 16, no. 7 (July 24, 2012): 2299–310. http://dx.doi.org/10.5194/hess-16-2299-2012.
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Abstract. Open ditch drainage has historically been a common land management practice in upland blanket peats, particularly in the UK. However, peatland drainage is now generally considered to have adverse effects on the upland environment, including increased peak flows. As a result, drain blocking has become a common management strategy in the UK over recent years, although there is only anecdotal evidence to suggest that this might decrease peak flows. The change in the hydrological regime associated with the drainage of blanket peat and the subsequent blocking of drains is poorly understood, therefore a new physics-based model has been developed that allows the exploration of the associated hydrological processes. A series of simulations is used to explore the response of intact, drained and blocked drain sites at field scales. While drainage is generally found to increase peak flows, the effect of drain blocking appears to be dependent on local conditions, sometimes decreasing and sometimes increasing peak flows. Based on insights from these simulations we identify steep smooth drains as those that would experience the greatest reduction in field-scale peak flows if blocked and recommend that future targeted field studies should be focused on examining surface runoff characteristics.
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Hoffman, Matthew J., Andrew G. Fountain, and Glen E. Liston. "Near-surface internal melting: a substantial mass loss on Antarctic Dry Valley glaciers." Journal of Glaciology 60, no. 220 (2014): 361–74. http://dx.doi.org/10.3189/2014jog13j095.
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AbstractThe McMurdo Dry Valleys, southern Victoria Land, East Antarctica, are a polar desert, and melt from glacial ice is the primary source of water to streams, lakes and associated ecosystems. Previous work found that to adequately model glacier ablation and subsurface ice temperatures with a surface energy-balance model required including the transmission of solar radiation into the ice. Here we investigate the contribution of subsurface melt to the mass balance of (and runoff from) Dry Valley glaciers by including a drainage process in the model and applying the model to three glacier sites using 13 years of hourly meteorological data. Model results for the smooth glacier surfaces common to many glaciers in the Dry Valleys showed that sublimation was typically the largest component of surface lowering, with rare episodes of surface melting, consistent with anecdotal field observations. Results also showed extensive internal melting 5–15 cm below the ice surface, the drainage of which accounted for ~50% of summer ablation. This is consistent with field observations of subsurface streams and formation of a weathering crust. We identify an annual cycle of weathering crust formation in summer and its removal during the 10 months of winter sublimation.
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Pan, Xicai, Warren Helgason, Andrew Ireson, and Howard Wheater. "Field-scale water balance closure in seasonally frozen conditions." Hydrology and Earth System Sciences 21, no. 11 (November 1, 2017): 5401–13. http://dx.doi.org/10.5194/hess-21-5401-2017.
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Abstract. Hydrological water balance closure is a simple concept, yet in practice it is uncommon to measure every significant term independently in the field. Here we demonstrate the degree to which the field-scale water balance can be closed using only routine field observations in a seasonally frozen prairie pasture field site in Saskatchewan, Canada. Arrays of snow and soil moisture measurements were combined with a precipitation gauge and flux tower evapotranspiration estimates. We consider three hydrologically distinct periods: the snow accumulation period over the winter, the snowmelt period in spring, and the summer growing season. In each period, we attempt to quantify the residual between net precipitation (precipitation minus evaporation) and the change in field-scale storage (snow and soil moisture), while accounting for measurement uncertainties. When the residual is negligible, a simple 1-D water balance with no net drainage is adequate. When the residual is non-negligible, we must find additional processes to explain the result. We identify the hydrological fluxes which confound the 1-D water balance assumptions during different periods of the year, notably blowing snow and frozen soil moisture redistribution during the snow accumulation period, and snowmelt runoff and soil drainage during the melt period. Challenges associated with quantifying these processes, as well as uncertainties in the measurable quantities, caution against the common use of water balance residuals to estimate fluxes and constrain models in such a complex environment.
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Rietveld, Matthijs, Demi de Rijke, Jeroen Langeveld, and Francois Clemens. "Sediment Morphology and the Flow Velocity Field in a Gully Pot: An Experimental Study." Water 12, no. 10 (October 21, 2020): 2937. http://dx.doi.org/10.3390/w12102937.
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Urban runoff (re)mobilises solids present on the street surface and transport them to urban drainage systems. The solids reduce the hydraulic capacity of the drainage system due to sedimentation and on the quality of receiving water bodies due to discharges via outfalls and combined sewer overflows (CSOs) of solids and associated pollutants. To reduce these impacts, gully pots, the entry points of the drainage system, are typically equipped with a sand trap, which acts as a small settling tank to remove suspended solids. This study presents data obtained using Particle Image Velocimetry (PIV) and Laser Doppler Anemometry (LDA) measurements in a scale 1:1 gully to quantify the relation between parameters such as the gully pot geometry, discharge, sand trap depth, and sediment bed level on the flow field and subsequently the settling and erosion processes. The results show that the dynamics of the morphology of the sediment bed influences the flow pattern and the removal efficiency in a significant manner, prohibiting the conceptualization of a gully pot as a completely mixed reactor. Resuspension is initiated by the combination of both high turbulent fluctuations and high mean flow, which is present when a substantial bed level is present. In case of low bed levels, the overlaying water protects the sediment bed from erosion.
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Westerlund, C., M. Viklander, and M. Bäckström. "Seasonal variations in road runoff quality in Luleå, Sweden." Water Science and Technology 48, no. 9 (November 1, 2003): 93–101. http://dx.doi.org/10.2166/wst.2003.0501.
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In regions with cold climate the urban drainage and highway runoff processes become much more complex, compared to temperate regions. Therefore, climatic conditions should be taken into account in planning and design of BMPs and snow handling strategies. In order to increase the knowledge of road runoff quality during melt and rain periods, respectively, measurements were carried out at a field site during a two-month period. The field site was situated at Södra Hamnleden, a road with 7,400 vehicles/day, in the central part of Luleå. Runoff samples were analysed for suspended solids and heavy metals (Pb, Cu, Cd, Ni and Zn). The results showed that the concentrations of suspended solids, lead, copper and cadmium were higher for the melt period, compared to rain generated runoff on the catchment without snow, and the highest concentrations were found during the rain-on-snow events. The results indicate a flow dependent increase in the concentration of suspended solids during the melt period. A comparison of the total mass of suspended solids over a one-month period showed that the melt period produced about 3 times more suspended solids. Metal elements during melt period were more particulate bound as compared to the rain period characterised by a higher percentage of the dissolved fraction.
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Butterworth, J. A., F. Mugabe, L. P. Simmonds, and M. G. Hodnett. "Hydrological processes and water resources management in a dryland environment II: Surface redistribution of rainfall within fields." Hydrology and Earth System Sciences 3, no. 3 (September 30, 1999): 333–43. http://dx.doi.org/10.5194/hess-3-333-1999.
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Abstract. Soil water movement was studied within fields on two different soil types, a red clay soil and a duplex soil of sand over clay, at the Romwe Catchment in southern Zimbabwe. Each study site comprised two fields and formed a surface water sub-catchment (1.0-2.4 ha) from which runoff was gauged. Soil moisture was measured in-situ at up to 20 locations within each sub-catchment over an entire cropping season and the following dry season. Maize was cultivated at both sites according to the farmers' normal cropping practice and crop yields were recorded. Surface redistribution of rainfall through localised runon and runoff was shown to be an important process in both sub-catchments with rainfall concentration factors between 0.2 and 2.7 for major rainfall events. This process was a key factor controlling deep drainage to groundwater. Results indicate that surface water redistribution is of particular importance for groundwater recharge in years with low or evenly distributed rainfall, when it would not otherwise have occurred. The soil water conditions created by surface redistribution of rainfall are also actively exploited by farmers who vary cropping practices within fields to maximise crop yields and reduce the risks of crop failure.
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Avilés, Daniel, Ingrid Wesström, and Abraham Joel. "Status Assessment of Agricultural Drainage Ditches." Transactions of the ASABE 61, no. 1 (2018): 263–71. http://dx.doi.org/10.13031/trans.12307.
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Abstract. Poor maintenance, environmental concerns, land use changes, and adaptation to climate change are creating a growing need for better agricultural drainage. The objectives of this study were to identify ditch properties that can be evaluated visually on-site and related soil erosion processes, and to define parameters requiring more intensive study and estimate these using simplified methods. The study included surveys of ditches in various soils using MADRAS (Minnesota Agricultural Ditch Research Assessment for Stability) to classify ditch status. To explain why some ditch segments were in poor condition, additional field and laboratory studies were carried out. Soil samples were taken for analysis of particle size distribution, unsaturated direct shear strength, and critical stress for erosion. The HEC-RAS data model was used for simulation of hydraulic forces acting at different flow rates. Digital maps of land use in the catchment area in different years were used to estimate changes in runoff conditions over time. MADRAS proved to be a suitable tool for rapid assessment of stability problems in ditches. The HEC-RAS simulations were a good complement to MADRAS in assessing how changes in land use affected the hydraulic load and in highlighting bottlenecks in the system. However, the hydraulic load did not adequately explain the degree of degradation in some ditch segments. Measurements of soil shear strength were a good aid to understanding existing degradation. Thus, assessment of soil erodibility and bank stability is essential in anticipating the risk of future erosion processes in ditches. Keywords: Cohesive strength meter, HEC-RAS, MADRAS, Unsaturated direct shear strength.
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Yahya, Noor Ain, Carolyn Payus, and Kawi Bidin. "REVIEW ON THE ROLE OF EARTHWORMS ON HILLSLOPE HYDROLOGY AND SOIL EROSION WITH SPECIAL REFERENCE TO DANUM VALLEY, SABAH, MALAYSIA." Journal CleanWAS 4, no. 2 (December 7, 2020): 84–88. http://dx.doi.org/10.26480/jcleanwas.02.2020.84.88.
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Hydrological routes exist through active burrowing of soil fauna, and in numbers improve soil drainage systems. Earthworms are of particular interest because their presence is known widely to increase infiltration and reduce erosion rates by creating macropores and stable casts. Ideally during non-extreme rainfall events on flatlands, earthworm macropores lengthens the time prior to soil surface saturation thus slowing down occasions of overland flow resulting in runoff. Hypothesizing similar effects on hillslopes with gradients can be misleading whereas laboratory experiments which try to recreate and simulate field consistency cannot match the natural soil architecture which is vital in the dissection of the many bio-geophysical processes involved in the rainfall-runoff process. This review paper aims to summarize past studies conducted around the world and highlighting possible gaps on earthworm’s studies related to hillslopes and erosion.
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Dominguez, Steven, and Kenneth E. Kolm. "Beyond Water Harvesting: A Soil Hydrology Perspective on Traditional Southwestern Agricultural Technology." American Antiquity 70, no. 4 (October 2005): 732–65. http://dx.doi.org/10.2307/40035872.
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This article presents a hypothetical, general model that describes the processes involved in one aspect of traditional Southwestern agriculture: the interactions between soil hydrology and farming technology. In conjunction with extensive participation in hand cultivation with Hopi farmers, studies of soil hydrologic processes in Hopi maize fields have identified hydrological processes directly linked to Hopi field location criteria and farming practices. Field location criteria select for locations where soil textures and soil profile heterogeneity control rates of moisture infiltration, as well as loss to runoff, bare soil evaporation, and drainage. Farming practices, including clearing, maintenance, plant spacing, seed depth, and planting pit morphology, operate in conjunction with soil profile attributes to increase the amount of moisture available to plants and the mobility of that moisture. Effects of both soil profile attributes and farming practices are integrated into the discrete soil volume model of hydrologic processes occurring in the basic unit of Hopi farming, the individual plant clump. This information provides basic insights on ways archaeologists might evaluate the productive potentials of soils, the extent of farmable land around prehistoric communities, and the ranges of climate conditions that permit crop growth on that land.
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Yan, Renhua, Junfeng Gao, and Lingling Li. "Modeling the hydrological effects of climate and land use/cover changes in Chinese lowland polder using an improved WALRUS model." Hydrology Research 47, S1 (May 3, 2016): 84–101. http://dx.doi.org/10.2166/nh.2016.204.
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Hydrological processes in lowland polders, especially those for paddy rice planting, are affected by complicated factors. The improved Wageningen Lowland Runoff Simulator (WALRUS) model incorporates an irrigation and drainage scheme, and a new stage–discharge relationship to account for hydrological processes in multi-land-use polder with paddy fields and pumping stations. Here, this model was applied to assess how climate and land use changes affected the runoff of a Chinese polder in Poyang Lake basin in the past two decades. Simulated results showed that the runoff in the autumn–winter transition and midsummer months increased significantly, whereas those in the other months decreased slightly during the period of 1996–2005, primarily affected by climate change. For the period of 2006–2014, the runoff in the autumn–winter transition and midsummer increased, while that in the other months declined, affected by both climate and land use/cover changes. The land use/cover change resulting from the conversion of rice–wheat rotation to dominantly double-rice cropping and the expansion of residential area, increased the runoff during this period by demanding more irrigation water from the outside basin.
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Darvishan, Abdulvahed Khaledi, Kazimierz Banasik, Seyed Hamidreza Sadeghi, Leila Gholami, and Leszek Hejduk. "Effects of Rain Intensity and Initial Soil Moisture on Hydrological Responses in Laboratory Conditions." International Agrophysics 29, no. 2 (April 1, 2015): 165–73. http://dx.doi.org/10.1515/intag-2015-0020.
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Abstract Although the possibility of measuring and analysing all parts of the rainfall, infiltration, runoff, and erosion process as a natural hydrologic cycle in field conditions is still one of the more unattainable goals in the hydrological sciences, it can be accomplished in laboratory conditions as a way to understand the whole process. The initial moisture content is one of the most effective factors on soil infiltration, runoff, and erosion responses. The present research was conducted on a 2 m2 laboratory plot at a slope of 9% on a typical sandy-loam soil. The effects of the initial soil moisture content on the infiltration, runoff, and erosion processes were studied at four levels of initial soil moisture content (12, 25, 33, and 40 volumetric percentage) and two rainfall intensities (60 and 120 mm h-1). The results showed a significant (p ≤ 0.05) correlation between rainfall intensity and downstream splash, with r = 0.87. The results reflected the theory of hydrological responses, showing significant (p ≤ 0.05) correlations with r =-0.93, 0.98, -0.83, 0.88, and 0.73 between the initial soil moisture content and the time-to-runoff, runoff coefficient, drainage as a part of the infiltrated water, downstream splash, and total outflow sediment, respectively.
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Napier, F., C. Jefferies, K. V. Heal, P. Fogg, B. J. D. Arcy, and R. Clarke. "Evidence of traffic-related pollutant control in soil-based Sustainable Urban Drainage Systems (SUDS)." Water Science and Technology 60, no. 1 (July 1, 2009): 221–30. http://dx.doi.org/10.2166/wst.2009.326.
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SUDS are being increasingly employed to control highway runoff and have the potential to protect groundwater and surface water quality by minimising the risks of both point and diffuse sources of pollution. While these systems are effective at retaining polluted solids by filtration and sedimentation processes, less is known of the detail of pollutant behaviour within SUDS structures. This paper reports on investigations carried out as part of a co-ordinated programme of controlled studies and field measurements at soft-engineered SUDS undertaken in the UK, observing the accumulation and behaviour of traffic-related heavy metals, oil and PAHs. The field data presented were collected from two extended detention basins serving the M74 motorway in the south-west of Scotland. Additional data were supplied from an experimental lysimeter soil core leaching study. Results show that basin design influences pollutant accumulation and behaviour in the basins. Management and/or control strategies are discussed for reducing the impact of traffic-related pollutants on the aqueous environment.
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Rinaldo, A., G. Botter, E. Bertuzzo, A. Uccelli, T. Settin, and M. Marani. "Transport at basin scales: 2. Applications." Hydrology and Earth System Sciences Discussions 2, no. 4 (August 23, 2005): 1641–81. http://dx.doi.org/10.5194/hessd-2-1641-2005.
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Abstract. In this paper, the second of a series, we apply the models discussed in Part 1 to a significant case study. The nature of the catchment under study, the transport phenomena investigated (i.e. nitrates moving as solutes within runoff waters) and the scales involved in space and time, provide an elaborate test for theory and applications. Comparison of modeling predictions with field data (i.e. fluxes of carrier flow and solute nitrates) suggests that the framework proposed for geomorphic transport models is capable to describe well large-scale transport phenomena driven and/or controlled by spatially distributed hydrologic fields (e.g. rainfall patterns in space and time, drainage pathways, soil coverage and type, matter stored in immobile phases). A sample MonteCarlo mode of application of the model is also discussed where hydrologic forcings and external nitrate applications (through fertilization) are treated as random processes.
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Rinaldo, A., G. Botter, E. Bertuzzo, A. Uccelli, T. Settin, and M. Marani. "Transport at basin scales: 2. Applications." Hydrology and Earth System Sciences 10, no. 1 (February 8, 2006): 31–48. http://dx.doi.org/10.5194/hess-10-31-2006.
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Abstract. In this paper, the second of a series, we apply the models discussed in Part 1 to a significant case study. The nature of the catchment under study, the transport phenomena investigated (i.e. nitrates moving as solutes within runoff waters) and the scales involved in space and time, provide an elaborate test for theory and applications. Comparison of modeling predictions with field data (i.e. fluxes of carrier flow and solute nitrates) suggests that the framework proposed for geomorphic transport models is capable to describe well large-scale transport phenomena driven and/or controlled by spatially distributed hydrologic fields (e.g. rainfall patterns in space and time, drainage pathways, soil coverage and type, matter stored in immobile phases). A sample MonteCarlo mode of application of the model is also discussed where hydrologic forcings and external nitrate applications (through fertilization) are treated as random processes.
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Harp, Dylan R., Vitaly Zlotnik, Charles J. Abolt, Bob Busey, Sofia T. Avendaño, Brent D. Newman, Adam L. Atchley, Elchin Jafarov, Cathy J. Wilson, and Katrina E. Bennett. "New insights into the drainage of inundated ice-wedge polygons using fundamental hydrologic principles." Cryosphere 15, no. 8 (August 23, 2021): 4005–29. http://dx.doi.org/10.5194/tc-15-4005-2021.
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Abstract. The pathways and timing of drainage from the inundated centers of ice-wedge polygons in a warming climate have important implications for carbon flushing, advective heat transport, and transitions from methane to carbon dioxide dominated emissions. Here, we expand on previous research using a recently developed analytical model of drainage from a low-centered polygon. Specifically, we perform (1) a calibration to field data identifying necessary model refinements and (2) a rigorous model sensitivity analysis that expands on previously published indications of polygon drainage characteristics. This research provides intuition on inundated polygon drainage by presenting the first in-depth analysis of drainage within a polygon based on hydrogeological first principles. We verify a recently developed analytical solution of polygon drainage through a calibration to a season of field measurements. Due to the parsimony of the model, providing the potential that it could fail, we identify the minimum necessary refinements that allow the model to match water levels measured in a low-centered polygon. We find that (1) the measured precipitation must be increased by a factor of around 2.2, and (2) the vertical soil hydraulic conductivity must decrease with increasing thaw depth. Model refinement (1) accounts for runoff from rims into the ice-wedge polygon pond during precipitation events and possible rain gauge undercatch, while refinement (2) accounts for the decreasing permeability of deeper soil layers. The calibration to field measurements supports the validity of the model, indicating that it is able to represent ice-wedge polygon drainage dynamics. We then use the analytical solution in non-dimensional form to provide a baseline for the effects of polygon aspect ratios (radius to thaw depth) and coefficient of hydraulic conductivity anisotropy (horizontal to vertical hydraulic conductivity) on drainage pathways and temporal depletion of ponded water from inundated ice-wedge polygon centers. By varying the polygon aspect ratio, we evaluate the relative effect of polygon size (width), inter-annual increases in active-layer thickness, and seasonal increases in thaw depth on drainage. The results of our sensitivity analysis rigorously confirm a previous analysis indicating that most drainage through the active layer occurs along an annular region of the polygon center near the rims. This has important implications for transport of nutrients (such as dissolved organic carbon) and advection of heat towards ice-wedge tops. We also provide a comprehensive investigation of the effect of polygon aspect ratio and anisotropy on drainage timing and patterns, expanding on previously published research. Our results indicate that polygons with large aspect ratios and high anisotropy will have the most distributed drainage, while polygons with large aspect ratios and low anisotropy will have their drainage most focused near their periphery and will drain most slowly. Polygons with small aspect ratios and high anisotropy will drain most quickly. These results, based on parametric investigation of idealized scenarios, provide a baseline for further research considering the geometric and hydraulic complexities of ice-wedge polygons.
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Fitzpatrick, A. A. W., A. L. Hubbard, J. E. Box, D. J. Quincey, D. van As, A. P. B. Mikkelsen, S. H. Doyle, C. F. Dow, B. Hasholt, and G. A. Jones. "A decade of supraglacial lake volume estimates across a land-terminating margin of the Greenland Ice Sheet." Cryosphere Discussions 7, no. 2 (April 3, 2013): 1383–414. http://dx.doi.org/10.5194/tcd-7-1383-2013.
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Abstract. Supraglacial lakes represent an ephemeral storage buffer for runoff and lead to significant, yet short-lived, episodes of ice-flow acceleration by decanting large fluxes of meltwater and energy into the ice sheet's hydrological system. Here, a field-validated methodology for calculating lake volume is used to quantify storage and drainage across Russell Glacier catchment, west Greenland, from 2002 onwards. Using 502 optical satellite images, water volume at ~200 seasonally occurring lakes was derived from a depth-reflectance relationship, independently calibrated and field-validated against lake bathymetry. Inland expansion of lakes is strongly correlated with air temperature: during the record melt years of 2010 and 2012, lakes formed and drained earlier, attaining their maximum volume 38 and 20 days before the 11 yr mean, as well as occupying a greater area and forming at higher elevations (>1800 m) than previously. Although lakes occupy only 2% of the catchment surface area, they temporarily store up to 13% of the bulk meltwater discharged. Across Russell Glacier, 28% of supraglacial lakes drain rapidly and clustering of such events in space and time suggests a synoptic trigger-mechanism. Furthermore, we find no evidence to support a unifying critical size or depth-dependent drainage threshold hypothesis.
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Bell, M. J., B. J. Bridge, G. R. Harch, and D. N. Orange. "Rapid internal drainage rates in Ferrosols." Soil Research 43, no. 4 (2005): 443. http://dx.doi.org/10.1071/sr04063.
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Adoption of conservation tillage practices on Red Ferrosol soils in the inland Burnett area of south-east Queensland has been shown to reduce runoff and subsequent soil erosion. However, improved infiltration resulting from these measures has not improved crop performance and there are suggestions of increased loss of soil water via deep drainage. This paper reports data monitoring soil water under real and artificial rainfall events in commercial fields and long-term tillage experiments, and uses the data to explore the rate and mechanisms of deep drainage in this soil type. Soils were characterised by large drainable porosities (≥0.10 m3/m3) in all parts of the profile to depths of 1.50 m, with drainable porosity similar to available water content (AWC) at 0.25 and 0.75 m, but >60% higher than AWC at 1.50 m. Hydraulic conductivity immediately below the tilled layer in both continuously cropped soils and those after a ley pasture phase was shown to decline with increasing soil moisture content, although the rate of decline was much greater in continuously cropped soil. At moisture contents approaching the drained upper limit (pore water pressure = –100 cm H2O), estimates of saturated hydraulic conductivity after a ley pasture were 3–5 times greater than in continuously cropped soil, suggesting much greater rates of deep drainage in the former when soils are moist. Hydraulic tensiometers and fringe capacitance sensors monitored during real and artificial rainfall events showed evidence of soils approaching saturation in the surface layers (top 0.30–0.40 m), but there was no evidence of soil moistures exceeding the drained upper limit (i.e. pore water pressures ≤ –100 cm H2O) in deeper layers. Recovery of applied soil water within the top 1.00–1.20 m of the profile during or immediately after rainfall events declined as the starting profile moisture content increased. These effects were consistent with very rapid rates of internal drainage. Sensors deeper in the profile were unable to detect this drainage due to either non-uniformity of conducting macropores (ie. bypass flow) or unsaturated conductivities in deeper layers that far exceed the saturated hydraulic conductivity of the infiltration throttle at the bottom of the cultivated layer. Large increases in unsaturated hydraulic conductivities are likely with only small increases in water content above the drained upper limit. Further studies with drainage lysimeters and large banks of hydraulic tensiometers are planned to quantify drainage risk in these soil types.
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Harrigan, S., C. Murphy, J. Hall, R. L. Wilby, and J. Sweeney. "Attribution of detected changes in streamflow using multiple working hypotheses." Hydrology and Earth System Sciences Discussions 10, no. 10 (October 15, 2013): 12373–416. http://dx.doi.org/10.5194/hessd-10-12373-2013.
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Abstract. This paper revisits a widely cited study of the Boyne catchment in the east of Ireland that attributed a change in streamflow during the mid-1970s to increased precipitation linked to a shift in the North Atlantic Oscillation. Using the method of Multiple Working Hypotheses we explore a wider set of potential drivers of hydrological change. Rainfall-runoff models are employed to reconstruct streamflow to isolate the effect of climate taking account of both model structure and parameter uncertainty. The Mann–Kendall test for monotonic trend and Pettitt change point test are applied to explore signatures of change. Different to earlier work, arterial drainage and the simultaneous onset of field drainage in the 1970s and early 1980s were inferred to be the predominant driver of change within the Boyne. There is evidence that a change in precipitation regime is also present, albeit to a lesser extent. This new explanation posits that multiple drivers acting simultaneously were responsible for the observed change. This work highlights the utility of the Multiple Working Hypotheses framework in moving towards more rigorous attribution, which is an important part of managing unfolding impacts on hydrological systems.
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Yi, Xueying, Danyang Su, Bruno Bussière, and K. Mayer. "Thermal-Hydrological-Chemical Modeling of a Covered Waste Rock Pile in a Permafrost Region." Minerals 11, no. 6 (May 26, 2021): 565. http://dx.doi.org/10.3390/min11060565.
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In order to reduce contaminant mass loadings, thermal cover systems may be incorporated in the design of waste rock piles located in regions of continuous permafrost. In this study, reactive transport modeling was used to improve the understanding of coupled thermo-hydrological and chemical processes controlling the evolution of a covered waste rock pile located in Northern Canada. Material properties from previous field and laboratory tests were incorporated into the model to constrain the simulations. Good agreement between simulated and observational temperature data indicates that the model is capable of capturing the coupled thermo-hydrological processes occurring within the pile. Simulations were also useful for forecasting the pile’s long-term evolution with an emphasis on water flow and heat transport mechanisms, but also including geochemical weathering processes and sulfate mass loadings as an indicator for the release of contaminated drainage. An uncertainty analysis was carried out to address different scenarios of the cover’s performance as a function of the applied infiltration rate, accounting for the impacts of evaporation, runoff, and snow ablation. The model results indicate that the cover performance is insensitive to the magnitude of recharge rates, except for limited changes of the flow regime in the shallow active layer. The model was expanded by performing an additional sensitivity analysis to assess the role of cover thicknesses. The simulated results reveal that a cover design with an appropriate thickness can effectively minimize mass loadings in drainage by maintaining the active layer completely within the cover.
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Mankoff, Kenneth D., and Slawek M. Tulaczyk. "The past, present, and future viscous heat dissipation available for Greenland subglacial conduit formation." Cryosphere 11, no. 1 (January 30, 2017): 303–17. http://dx.doi.org/10.5194/tc-11-303-2017.
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Abstract. Basal hydrology of the Greenland Ice Sheet (GIS) influences its dynamics and mass balance through basal lubrication and ice–bed decoupling or efficient water removal and ice–bed coupling. Variations in subglacial water pressure through the seasonal evolution of the subglacial hydrological system help control ice velocity. Near the ice sheet margin, large basal conduits are melted by the viscous heat dissipation (VHD) from surface runoff routed to the bed. These conduits may lead to efficient drainage systems that lower subglacial water pressure, increase basal effective stress, and reduce ice velocity. In this study we quantify the energy available for VHD historically at present and under future climate scenarios. At present, 345 km3 of annual runoff delivers 66 GW to the base of the ice sheet per year. These values are already ∼ 50 % more than the historical 1960–1999 value of 46 GW. By 2100 under IPCC AR5 RCP8.5 (RCP4.5) scenarios, 1278 (524) km3 of runoff may deliver 310 (110) GW to the ice sheet base. Hence, the ice sheet may experience a 5-to-7-fold increase in VHD in the near future which will enhance opening of subglacial conduits near the margin and will warm basal ice in the interior. The other significant basal heat source is geothermal heat flux (GHF), which has an estimated value of 36 GW within the present-day VHD area. With increasing surface meltwater penetration to the bed the basal heat budget in the active basal hydrology zone of the GIS will be increasingly dominated by VHD and relatively less sensitive to GHF, which may result in spatial changes in the ice flow field and in its seasonal variability.
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Velluet, C., J. Demarty, B. Cappelaere, I. Braud, H. B. A. Issoufou, N. Boulain, D. Ramier, et al. "Building a field- and model-based climatology of local water and energy cycles in the cultivated Sahel – annual budgets and seasonality." Hydrology and Earth System Sciences Discussions 11, no. 5 (May 13, 2014): 4753–808. http://dx.doi.org/10.5194/hessd-11-4753-2014.
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Abstract. In the African Sahel, energy and water cycling at the land surface is pivotal for regional climate, water resources and land productivity, yet it is still extremely poorly documented. As a step towards a comprehensive climatological description of surface fluxes in this area, this study provides estimates of average annual budgets and seasonal cycles for two main land use types of the cultivated Sahelian belt, rainfed millet crop and fallow bush. These estimates build on the combination of a 7 year field dataset from two typical plots in southwestern Niger with detailed physically-based soil-plant-atmosphere modelling, yielding a continuous, comprehensive set of water and energy flux and storage variables over the 7 year period. In this study case in particular, blending field data with mechanistic modelling is considered as making best use of available data and knowledge for such purpose. It extends observations by reconstructing missing data and extrapolating to unobserved variables or periods. Furthermore, model constraining with observations compromises between extraction of observational information content and integration of process understanding, hence accounting for data imprecision and departure from physical laws. Climatological averages of all water and energy variables, with associated sampling uncertainty, are derived at annual to subseasonal scales from the 7 year series produced. Similarities and differences in the two ecosystems behaviors are highlighted. Mean annual evapotranspiration is found to represent ~82–85% of rainfall for both systems, but with different soil evaporation/plant transpiration partitioning and different seasonal distribution. The remainder consists entirely of runoff for the fallow, whereas drainage and runoff stand in a 40–60% proportion for the millet field. These results should provide a robust reference for the surface energy- and water-related studies needed in this region. The model developed in this context has the potential for reliable simulations outside the reported conditions, including changing climate and land cover.
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Fitzpatrick, A. A. W., A. L. Hubbard, J. E. Box, D. J. Quincey, D. van As, A. P. B. Mikkelsen, S. H. Doyle, C. F. Dow, B. Hasholt, and G. A. Jones. "A decade (2002–2012) of supraglacial lake volume estimates across Russell Glacier, West Greenland." Cryosphere 8, no. 1 (January 14, 2014): 107–21. http://dx.doi.org/10.5194/tc-8-107-2014.
Full textAbstract:
Abstract. Supraglacial lakes represent an ephemeral storage buffer for meltwater runoff and lead to significant, yet short-lived, episodes of ice-flow acceleration by decanting large meltwater and energy fluxes into the ice sheet's hydrological system. Here, a methodology for calculating lake volume is used to quantify storage and drainage across Russell Glacier, West Greenland, between 2002 and 2012. Using 502 MODIS scenes, water volume at ~200 seasonally occurring lakes was derived using a depth–reflectance relationship, which was independently calibrated and field validated against lake bathymetry. The inland expansion of lakes is strongly correlated with air temperature: during the record melt years of 2010 and 2012, lakes formed and drained earlier, attaining their maximum volume 38 and 20 days earlier than the 11 yr mean, as well as occupying a greater area and forming at higher elevations (> 1800 m) than previously. Despite occupying under 2% of the study area, lakes delay the transmission of up to 7–13% of the bulk meltwater discharged. Although the results are subject to an observational bias caused by periods of cloud cover, we estimate that across Russell Glacier, 28% of supraglacial lakes drain rapidly (< 4 days). Clustering of such events in space and time suggests a synoptic trigger mechanism. Further, we find no evidence to support a unifying critical size or depth-dependent drainage threshold.
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Vergnes, J. P., and B. Decharme. "A simple groundwater scheme in the TRIP river routing model: global off-line evaluation against GRACE terrestrial water storage estimates and observed river discharges." Hydrology and Earth System Sciences Discussions 9, no. 7 (July 4, 2012): 8213–56. http://dx.doi.org/10.5194/hessd-9-8213-2012.
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Abstract. Groundwater is a non-negligible component of the global hydrological cycle, and its interaction with its overlying unsaturated zones can influence water and energy fluxes between the land surface and the atmosphere. Despite its importance, groundwater is not yet represented in most climate models. In this paper, the simple groundwater scheme implemented in the Total Runoff Integrating Pathways (TRIP) river routing model is applied in off-line mode at global scale using a 0.5° model resolution. The simulated river discharges are evaluated against a large dataset of about 3500 gauging stations compiled from the Global Data Runoff Center (GRDC) and other sources, while the Terrestrial Water Storage (TWS) variations derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission helps to evaluate the simulated TWS. The forcing fields (surface runoff and deep drainage) come from an independent simulation of the ISBA land surface model covering the period from 1950 to 2008. Results show that groundwater improves the efficiency scores for about 70% of the gauging stations and deteriorates them for 15%. The simulated TWS are also in better agreement with the GRACE estimates. These results are mainly explained by the lag introduced by the low-frequency variations of groundwater, which tend to shift and smooth the simulated river discharges and TWS. A sensitivity study on the global precipitation forcing used in ISBA to produce the forcing fields is also proposed. It shows that the groundwater scheme is not influenced by the uncertainties in precipitation data.
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Crosta, G. B., P. Dal Negro, and P. Frattini. "Soil slips and debris flows on terraced slopes." Natural Hazards and Earth System Sciences 3, no. 1/2 (April 30, 2003): 31–42. http://dx.doi.org/10.5194/nhess-3-31-2003.
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Abstract. Terraces cover large areas along the flanks of many alpine and prealpine valleys. Soil slips and soil slips-debris flows are recurrent phenomena along terraced slopes. These landslides cause damages to people, settlements and cultivations. This study investigates the processes related to the triggering of soil slip-debris flows in these settings, analysing those occurred in Valtellina (Central Alps, Italy) on November 2000 after heavy prolonged rainfalls. 260 landslides have been recognised, mostly along the northern valley flank. About 200 soil slips and slumps occurred in terraced areas and a third of them evolved into debris flows. Field work allowed to recognise the settings at soil slip-debris flow source areas. Landslides affected up to 2.5 m of glacial, fluvioglacial and anthropically reworked deposits overlying metamorphic basement. Laboratory and in situ tests allowed to characterise the geotechnical and hydraulic properties of the terrains involved in the initial failure. Several stratigraphic and hydrogeologic factors have been individuated as significant in determining instabilities on terraced slopes. They are the vertical changes of physical soil properties, the presence of buried hollows where groundwater convergence occurs, the rising up of perched groundwater tables, the overflow and lateral infiltration from superficial drainage network, the runoff concentration by means of pathways and the insufficient drainage of retaining walls.
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Paydar, Zahra, Neil Huth, Anthony Ringrose-Voase, Rick Young, Tony Bernardi, Brian Keating, and Hamish Cresswell. "Deep drainage and land use systems. Model verification and systems comparison." Australian Journal of Agricultural Research 56, no. 9 (2005): 995. http://dx.doi.org/10.1071/ar04303.
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Deep drainage or drainage below the bottom of the profile usually occurs when rain infiltrates moist soil with insufficient capacity to store the additional water. This drainage is believed to be contributing to watertable rise and salinity in some parts of the Liverpool Plains catchment in northern New South Wales. The effect of land use on deep drainage was investigated by comparing the traditional long fallow system with more intense ‘opportunity cropping’. Long fallowing (2 crops in 3 years) is used to store rainfall in the soil profile but risks substantial deep drainage. Opportunity cropping seeks to lessen this risk by sowing whenever there is sufficient soil moisture. Elements of the water balance and productivity were measured under various farming systems in a field experiment for 4 years in the southern part of the catchment. The experimental results were used to verify APSIM (Agricultural Production Systems Simulator) by comparing them with predictions of production, water storage, and runoff. The verification procedure also involved local farmers and agronomists who assessed the credibility of the predictions and suggested modifications. APSIM provided a realistic simulation of common farming systems in the region and could capture the main hydrological and biological processes. APSIM was then used for long-term (41 years) simulations to predict deep drainage under different systems and extrapolate experimental results. The results showed large differences between agricultural systems mostly because differences in evapotranspiration contributed to differences in profile moisture when it rained. The model predicted that traditional long fallow farming systems (2 crops in 3 years) are quite ‘leaky’, with average annual deep drainage of 34 mm. However, by planting crops in response to the depth of moist soil (opportunity or response cropping), APSIM predicted a much smaller annual drainage rate of 6 mm. Opportunity cropping resulted in overall greater water use and increased production compared with long fallowing. Furthermore, modelling indicated that average annual deep drainage under continuous sorghum (3 mm) is much less than under either long fallow cropping or continuous wheat (39 mm), demonstrating the importance of including summer cropping, as well as increasing cropping frequency, to reducing deep drainage.
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Hu, Dechao, Min Wang, Shiming Yao, and Zhongwu Jin. "Study on the Spillover of Sediment during Typical Tidal Processes in the Yangtze Estuary Using a High-Resolution Numerical Model." Journal of Marine Science and Engineering 7, no. 11 (November 1, 2019): 390. http://dx.doi.org/10.3390/jmse7110390.
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Because of special morphologies and complex runoff–tide interactions, the landward floodtide flows in Yangtze Estuary are observed to spill over from the North to the South Branches, carrying a lot of sediment. To quantitatively clarify the spillover problem, a two-dimensional numerical model using a high-resolution channel-refined unstructured grid is developed for the entire Yangtze Estuary from Datong to river mouths (620 km) and part of the East Sea. The developed model ensures a good description of the river-coast-ocean coupling, the irregular boundaries, and local river regimes in the Yangtze Estuary. In tests, the simulated histories of the tidal level, depth-averaged velocity, and sediment concentration agree well with field data. The spillover of sediment in the Yangtze Estuary is studied using the condition of a spring and a neap tide in dry seasons. For a representative cross-section in the upper reach of the North Branch (QLG), the difference of the cross-sectional sediment flux (CSSF) between floodtide and ebbtide durations is 43.85–11.26 × 104 t/day, accounting for 37.5–34.9% of the landward floodtide CSSF. The mechanics of sediment spillover in Yangtze Estuary are clarified in terms of a successive process comprising the source, transport, and drainage of the spillover sediment.
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Wang, L. P., S. Ochoa-Rodríguez, C. Onof, and P. Willems. "Singularity-sensitive gauge-based radar rainfall adjustment methods for urban hydrological applications." Hydrology and Earth System Sciences Discussions 12, no. 2 (February 6, 2015): 1855–900. http://dx.doi.org/10.5194/hessd-12-1855-2015.
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Abstract. Gauge-based radar rainfall adjustment techniques have been widely used to improve the applicability of radar rainfall estimates to large-scale hydrological modelling. However, their use for urban hydrological applications is limited as they were mostly developed based upon Gaussian approximations and therefore tend to smooth off so-called "singularities" (features of a non-Gaussian field) that can be observed in the fine-scale rainfall structure. Overlooking the singularities could be critical, given that their distribution is highly consistent with that of local extreme magnitudes. This deficiency may cause large errors in the subsequent urban hydrological modelling. To address this limitation and improve the applicability of adjustment techniques at urban scales, a method is proposed herein which incorporates a local singularity analysis into existing adjustment techniques and allows the preservation of the singularity structures throughout the adjustment process. In this paper the proposed singularity analysis is incorporated into the Bayesian merging technique and the performance of the resulting singularity-sensitive method is compared with that of the original Bayesian (non singularity-sensitive) technique and the commonly-used mean field bias adjustment. This test is conducted using as case study four storm events observed in the Portobello catchment (53 km2) (Edinburgh, UK) during 2011 and for which radar estimates, dense rain gauge and sewer flow records, as well as a recently-calibrated urban drainage model were available. The results suggest that, in general, the proposed singularity-sensitive method can effectively preserve the non-normality in local rainfall structure, while retaining the ability of the original adjustment techniques to generate nearly unbiased estimates. Moreover, the ability of the singularity-sensitive technique to preserve the non-normality in rainfall estimates often leads to better reproduction of the urban drainage system's dynamics, particularly of peak runoff flows.
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Miller, J. R., G. Mackin, P. Lechler, M. Lord, and S. Lorentz. "Influence of basin connectivity on sediment source, transport, and storage within the Mkabela Basin, South Africa." Hydrology and Earth System Sciences Discussions 9, no. 9 (September 6, 2012): 10151–204. http://dx.doi.org/10.5194/hessd-9-10151-2012.
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Abstract. The management of sediment and other non-point source (NPS) pollution has proven difficult, and requires a sound understanding of particle movement through the drainage system. The primary objective of this investigation was to obtain an understanding of NPS sediment source(s), transport, and storage within the Mkabela basin, a representative agricultural catchment within the KwaZulu-Natal Midlands of southeastern South Africa, by combining geomorphic, hydrologic and geochemical fingerprinting analyses. The Mkabela Basin can be subdivided into three distinct subcatchments that differ in their ability to transport and store sediment along the axial valley. Headwater (upper catchment) areas are characterized by extensive wetlands that act as significant sediment sinks. Mid-catchment areas, characterized by higher relief and valley gradients, exhibit few wetlands, but rather are dominated by a combination of alluvial and bedrock channels that are conducive to sediment transport. The lower catchment exhibits a low-gradient alluvial channel that is boarded by extensive riparian wetlands that accumulate large quantities of sediment (and NPS pollutants). Fingerprinting studies suggest that silt- and clay-rich layers found within wetland and reservoir deposits are derived from the erosion of fine-grained, valley bottom soils frequently utilized as vegetable fields. Coarser-grained deposits within both wetlands and reservoirs result from the erosion of sandier hillslope soils extensively utilized for sugar cane, during relatively high magnitude runoff events that are capable of transporting sand-sized sediment off the slopes. Thus, the source of sediment to the axial valley varies as a function of sediment size and runoff magnitude. Sediment export from the basin was limited until the early 1990s, in part because the upper catchment wetlands were hydrologically disconnected from lower parts of the watershed during low- to moderate flood events. The construction of a drainage ditch through a previously unchanneled wetland altered the hydrologic connectivity of the catchment, allowing sediment to be transported from the headwaters to the lower basin where much of it was deposited within the riparian wetlands. The axial drainage system is now geomorphically and hydrologically connected during most events throughout the study basin. The study indicates that increased valley connectivity partly negated the positive benefits of controlling sediment/nutrient exports from the catchment by means of upland based, best management practices.
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Fang, X., J. W. Pomeroy, C. J. Westbrook, X. Guo, A. G. Minke, and T. Brown. "Prediction of snowmelt derived streamflow in a wetland dominated prairie basin." Hydrology and Earth System Sciences Discussions 7, no. 1 (February 10, 2010): 1103–41. http://dx.doi.org/10.5194/hessd-7-1103-2010.
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Abstract. The eastern Canadian Prairies are dominated by cropland, pasture, woodland and wetland areas. The region is characterized by many poor and internal drainage systems and large amounts of surface water storage. Consequently, basins here have proven challenging to hydrological model predictions which assume good drainage to stream channels. The Cold Regions Hydrological Modelling platform (CRHM) is an assembly system that can be used to set up physically based, flexible, object oriented models. CRHM was used to create a prairie hydrological model for the externally drained Smith Creek Research Basin (~400 km2), east-central Saskatchewan. Physically based modules were sequentially linked in CRHM to simulate snow processes, frozen soils, variable contributing area and wetland storage and runoff generation. Five "representative basins" (RBs) were used and each was divided into seven hydrological response units (HRUs): fallow, stubble, grassland, river channel, open water, woodland, and wetland as derived from a supervised classification of SPOT 5 imagery. Two types of modelling approaches calibrated and uncalibrated, were set up for 2007/08 and 2008/09 simulation periods. For the calibrated modelling, only the surface depression capacity of upland area was calibrated in the 2007/08 simulation period by comparing simulated and observed hydrographs; while other model parameters and all parameters in the uncalibrated modelling were estimated from field observations of soils and vegetation cover, SPOT 5 imagery, and analysis of drainage network and wetland GIS datasets as well as topographic map based and LiDAR DEMs. All the parameters except for the initial soil properties and antecedent wetland storage were kept the same in the 2008/09 simulation period. The model performance in predicting snowpack, soil moisture and streamflow was evaluated and comparisons were made between the calibrated and uncalibrated modelling for both simulation periods. Calibrated and uncalibrated predictions of snow accumulation were very similar and compared fairly well with the distributed field observations for the 2007/08 period with slightly poorer results for the 2008/09 period. Soil moisture content at a point during the early spring was adequately simulated and very comparable between calibrated and uncalibrated results for both simulation periods. The calibrated modelling had somewhat better performance in simulating spring streamflow in both simulation periods, whereas the uncalibrated modelling was still able to capture the streamflow hydrographs with good accuracy. This suggests that prediction of prairie basins without calibration is possible if sufficient data on meteorology, basin landcover and physiography are available.
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Bariamis, George, and Evangelos Baltas. "Hydrological Modeling in Agricultural Intensive Watershed: The Case of Upper East Fork White River, USA." Hydrology 8, no. 3 (September 10, 2021): 137. http://dx.doi.org/10.3390/hydrology8030137.
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Identifying the core hydrological processes of catchments is a critical step for operative hydrological modeling. This study attempts to assess the long-term alterations in streamflow in three adjacent catchments of Upper East Fork White River, Indiana USA, by employing the SWAT hydrological model. The model simulations are spanning from 1980 up to 2015 and distributed in three configurations periods to identify monthly alterations in streamflow. For this purpose, water abstraction, land use, tillage, and agricultural field drainage practices have been incorporated in the model to provide accurate data input. The model setup also integrates spatially disaggregated sectorial water use data from surface and groundwater resources integrating the significant increases of water abstractions mainly for agricultural and public water supply purposes. The land cover of the study area is governed by rotating crops, while agricultural practices and tile drainage are crucial model parameters affecting the regional hydrological balance. Streamflow prediction is based on the SUFI-2 algorithm and the SWAT-CUP interface has been used for the monthly calibration and validation phases of the model. The evaluation of model simulations indicate a progressively sufficient hydrological model setup for all configuration periods with NSE (0.87, 0.88, and 0.88) and PBIAS (14%, −7%, and −2.8%) model evaluation values at the Seymour outlet. Surface runoff/precipitation as well as percolation/precipitation ratios have been used as indicators to identify trends to wetter conditions. Model outputs for the upstream areas, are successful predictions for streamflow assessment studies to test future implications of land cover and climate change.
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Kondratyev, S. A., A. Yu Bruchanov, N. V. Ignatyeva, A. E. Lapenkov, A. M. Rasulova, A. V. Terekhov, and N. S. Oblomkova. "Ecological problems of the river Novaya (St. Petersburg) and ways to solve them." HYDROMETEOROLOGY AND ECOLOGY. PROCEEDINGS OF THE RUSSIAN STATE HYDROMETEOROLOGICAL UNIVERSITY, no. 59 (2020): 94–110. http://dx.doi.org/10.33933/2074-2762-2020-59-94-110.
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Main sources of pollution of the river Novaya, one of the most ecologically unfavorable water bodies in St. Petersburg, have been revealed on the basis of hydrological, hydrochemical and geochemical data. The river lost natural water supply and its length decreased by 4 times after the runoff from the upper part of catchment was redirected to the river Dudergofka during the construction of the Pulkovo Airport several decades ago. Currently, the river is a drainage system of agricultural territory, supplying a system of six connected ponds at urban area. The main ecological problem of the aquatic system under study has been found to be nutrient and organic pollution. Main reason of pollution is intensive agricultural activity at the catchment area. As a result, a huge amount of phosphorus, nitrogen and organic substances enters the hydrographic network. Low flow rate of the water system makes worse the development of negative processes in the ecosystem. The main polluter is a livestock enterprise located in the upper part of the catchment area. It discharges wastewater into the drainage system in the catchment area and manures agricultural fields directly adjacent to the riverbed. In accordance with the evaluation criteria of the degree of surface waters chemical pollution, approved by the Ministry of Natural Resources of the Russian Federation, the situation is assessed as extreme in the aquatic system, and at some sites - as a zone of ecological disaster by a number of parameters. No contamination of water and bottom sediments, as well as soils in the catchment area with priority organic pollutants previously entering from the airport territory was detected. Nutrient loading on the aquatic system of the catchment area from the agricultural enterprise has been calculated. It has been assessed that the use of the best available technologies for agricultural activity could reduce the phosphorus load by 9 % and the nitrogen load by 28 %. Currently, the calculated concentration of total phosphorus in the drainage system in the catchment area is 4 times higher than the hyper eutrophic state limit. An improvement in the ecological situation can be achieved by optimizing agricultural activity in the catchment area, periodical removal of some nutrients and organic substances by mowing macrophytes in the swampy floodplain area, establishing a coastal protective zone and increasing the flow rate as a result of the return of runoff from the upper part of the river catchment to the former course
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Ghebrehiwot, Anghesom A., and Dmitriy V Kozlov. "Assessment of applicability of mike 11-nam hydrological module for rainfall runoff modelling in a poorly studied river basin." Vestnik MGSU, no. 7 (July 2020): 1030–46. http://dx.doi.org/10.22227/1997-0935.2020.7.1030-1046.
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Introduction. The need to simulate hydrological processes is caused by, among other factors, the complexity of hydrological systems and data insufficiency due to the unavailability or a small number of instrumental observations. Recently, the reanalysis of the climate data supplied by the world’s leading meteorological centres has been used quite successfully in the regions that suffer from the deficit of instrumental information. This paper assesses the applicability of climate reanalysis data to rainfall runoff (“rainfall runoff”) modelling in the poorly studied river basin in Eritrea.
Materials and methods. Climate Forecast System Reanalysis (CFSR) data generated by the National Centre for Environmental Prediction (USA) were used. Besides, high-resolution topographic information, generated by the SRTM international research project, was also applied to set the drainage area boundaries and to simulate the river network using such tools as MIKE and GIS. In addition, calibration and validation (evaluation) of the hydrological model (simulation quality) were performed using the Nash-Sutcliffe efficiency criterion, the determination coefficient, and the root mean square error of volumetric and peak flow rates.
Results. The results suggest that a considerable overestimation of precipitation in the reanalysis data set, which in turn has a significant effect on other variables such as potential evapotranspiration, leads to a significant discrepancy between water balance values which are simulated and registered by the hydrographs.
Conclusions. The applicability of Climate Forecast System Reanalysis (CFSR) data to river flow modelling in arid and semi-arid regions such as Eritrea is questionable. The incompatibility of spatial and temporal variations of initial variables (e.g. precipitation), derived from reanalysis data sets and instrumental observations, is undoubtedly the main reason for errors. Thus, the application of reanalysis data sets and development of hydrological models for the region under study requires further intensive research aimed at identifying most effective mechanisms designated for the harmonization of differences between reanalysis data and field observations. In the course of further research, CFSR information is to be converted into more realistic data; climate reanalysis indicators, provided by other sources and designated for different time scales in the context of the “rainfall runoff” model are to be assessed, and the efficiency of other software systems is to be compared with MIKE 11-NAM.
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Doppler, T., L. Camenzuli, G. Hirzel, M. Krauss, A. Lück, and C. Stamm. "Spatial variability of herbicide mobilisation and transport at catchment scale: insights from a field experiment." Hydrology and Earth System Sciences Discussions 9, no. 2 (February 22, 2012): 2357–407. http://dx.doi.org/10.5194/hessd-9-2357-2012.
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Abstract. During rain events, herbicides can be transported from their point of application to surface waters where they may harm aquatic organisms. Since the spatial pattern of mobilisation and transport is heterogeneous, the contributions of different fields to the herbicide load in the stream may differ considerably within one catchment. Therefore, the prediction of contributing areas could help to target mitigation measures efficiently to those locations where they reduce herbicide pollution the most. Such spatial predictions require sufficient insight into the underlying transport processes. To improve the understanding of the process chain of herbicide mobilisation on the field and the subsequent transport through the catchment to the stream, we performed a controlled herbicide application on corn fields in a small agricultural catchment (ca. 1 km2) with intensive crop production in the Swiss Plateau. For two months after application in 2009, water samples were taken at different locations in the catchment (overland flow, tile drains and open channel) with a high temporal resolution during rain events. We also analysed soil samples from the experimental fields and measured discharge, groundwater level, soil moisture and the occurrence of overland flow at several locations. Several rain events with varying intensities and magnitudes occurred during the study period. Overland flow and erosion were frequently observed in the entire catchment. Infiltration excess and saturation excess overland flow were both observed. However, the main herbicide loss event was dominated by infiltration excess. This is in contrast to earlier studies in the Swiss Plateau, demonstrating that saturation excess overland flow was the dominant process. Despite the frequent and wide-spread occurrence of overland flow, most of this water did not directly reach the channel. It mostly got retained in small sinks in the catchment. From there, it reached the stream via macropores and tile drains. Manholes of the drainage system and catch basins for road and farmyard runoff acted as additional shortcuts to the stream. Although fast flow processes like overland and macropore flow reduce the influence of herbicide properties due to short travel times, sorption properties influenced the herbicide transfer from ponding overland flow to tile drains (macropore flow). However, no influence of sorption was observed during the mobilisation of the herbicides from soil to overland flow. These two observations on the role of herbicide properties contradict, to some degrees, previous findings. They demonstrate that valuable insight can be gained by spatially detailed observations along the flow paths.
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Bilal, Ahmed, Qiancheng Xie, and Yanyan Zhai. "Flow, Sediment, and Morpho-Dynamics of River Confluence in Tidal and Non-Tidal Environments." Journal of Marine Science and Engineering 8, no. 8 (August 7, 2020): 591. http://dx.doi.org/10.3390/jmse8080591.
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River confluences are the key features of the drainage basins, as their hydrological, geomorphological, and ecological nature strongly influences the downstream river characteristics. The river reaches near the coastal zones, which also makes them under the influence of tidal currents in addition to their runoff. This causes a bi-directional flow and makes the study of confluences more interesting and complex in these areas. There is a reciprocal adjustment of flow, sediment, and morphology at a confluence, and its behaviors, differ greatly in tidal and non-tidal environments. Existing studies of the river junctions provide a good account of information about the hydrodynamics and bed morphology of the confluent areas, especially the unidirectional ones. The main factors which affect the flow field include the angle of confluence, flow-related ratios (velocity, discharge, and momentum) of the merging streams, and bed discordance. Hydraulically, six notable zones are identified for unidirectional confluences. However, for bi-directional (tidal) junctions, hydrodynamic zones always remain in transition but repeat in a cycle and make four different arrangements of flow features. This study discusses the hydrodynamics, sediment transport, morphological changes, and the factors affecting these processes and reviews the recent research about the confluences for these issues. All of these studies provide insights into the morpho-dynamics in tidal and non-tidal confluent areas.
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Doppler, T., L. Camenzuli, G. Hirzel, M. Krauss, A. Lück, and C. Stamm. "Spatial variability of herbicide mobilisation and transport at catchment scale: insights from a field experiment." Hydrology and Earth System Sciences 16, no. 7 (July 6, 2012): 1947–67. http://dx.doi.org/10.5194/hess-16-1947-2012.
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Abstract. During rain events, herbicides can be transported from their point of application to surface waters, where they may harm aquatic organisms. Since the spatial pattern of mobilisation and transport is heterogeneous, the contributions of different fields to the herbicide load in the stream may vary considerably within one catchment. Therefore, the prediction of contributing areas could help to target mitigation measures efficiently to those locations where they reduce herbicide pollution the most. Such spatial predictions require sufficient insight into the underlying transport processes. To improve the understanding of the process chain of herbicide mobilisation on the field and the subsequent transport through the catchment to the stream, we performed a controlled herbicide application on corn fields in a small agricultural catchment (ca. 1 km2) with intensive crop production in the Swiss Plateau. Water samples were collected at different locations in the catchment (overland flow, tile drains and open channel) for two months after application in 2009, with a high temporal resolution during rain events. We also analysed soil samples from the experimental fields and measured discharge, groundwater level, soil moisture and the occurrence of overland flow at several locations. Several rain events with varying intensities and magnitudes occurred during the study period. Overland flow and erosion were frequently observed in the entire catchment. Infiltration excess and saturation excess overland flow were both observed. However, the main herbicide loss event was dominated by infiltration excess. Despite the frequent and wide-spread occurrence of overland flow, most of this water did not reach the channel directly, but was retained in small depressions in the catchment. From there, it reached the stream via macropores and tile drains. Manholes of the drainage system and storm drains for road and farmyard runoff acted as additional shortcuts to the stream. Although fast flow processes such as overland and macropore flow reduce the influence of the herbicide's chemical properties on transport due to short travel times, sorption properties influenced the herbicide transfer from ponding overland flow to tile drains (macropore flow). However, no influence of sorption was observed during the mobilisation of the herbicides from soil to overland flow. These observations on the role of herbicide properties contradict previous findings to some degree. Furthermore, they demonstrate that valuable insight can be gained by making spatially detailed observations along the flow paths.
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Schmidt, A., J. J. Gibson, I. R. Santos, M. Schubert, and K. Tattrie. "The contribution of groundwater discharge to the overall water budget of Boreal lakes in Alberta/Canada estimated from a radon mass balance." Hydrology and Earth System Sciences Discussions 6, no. 4 (July 21, 2009): 4989–5018. http://dx.doi.org/10.5194/hessd-6-4989-2009.
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Abstract. Radon-222, a naturally-occurring radioisotope with a half-life of 3.8 days, was used to estimate groundwater discharge to small lakes in wetland-rich basins in the vicinity of Fort McMurray, Alberta, a region under significant water development pressures including both oil sands mining and in situ extraction. A program of field investigations was carried out in March and July 2008 using a Durridge RAD-7® and RAD Aqua® to measure radon-222 activity distributions in dissolved gas in the water column of two lakes as a tracer of groundwater discharge in the timeframe of 4 half-lives (15 days). Radon activity concentrations in lakes was found to range from 0.5 to 72 Bq/m3, compared to radon activity concentrations in groundwaters, measured using a RAD H2O, in the range of 2000–8000 Bq/m3. Radon mass balance, used in comparison with stable isotope mass balance, suggested that the two lakes under investigation had quite different proportions of annual groundwater inflow, one being close to 0.5% of annual inflow and the other about 14%, with lower values in the former attributed to a larger drainage area/lake area ratio which promotes greater surface connectivity. Interannual variability in groundwater proportions is expected despite constancy of groundwater discharge rates due to observed variability in annual surface runoff. Combination of stable isotope and radon mass balance approaches provides information on flowpath partitioning that is useful for evaluating surface-groundwater connectivity and acid sensitivity of individual water bodies of interest in the Alberta Oil Sands Region.
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Li, R. H., S. M. Liu, Y. W. Li, G. L. Zhang, J. L. Ren, and J. Zhang. "Nutrient dynamics in tropical rivers, lagoons, and coastal ecosystems of eastern Hainan Island, South China Sea." Biogeosciences 11, no. 2 (January 30, 2014): 481–506. http://dx.doi.org/10.5194/bg-11-481-2014.
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Abstract. Nutrient dynamics based on field observations made along the eastern Hainan Island during the period 2006–2009 were investigated to understand nutrient biogeochemical processes, and to provide an overview of human perturbations of coastal ecosystems in this tropical region. The rivers showed seasonal variations in nutrient concentrations, with enrichment of dissolved inorganic nitrogen and dissolved silicate, and depletion of PO43−. High riverine concentrations of nitrate mainly originated from agricultural fertilizer inputs. The DIN : PO43− ratios ranged from 37 to 1063, suggesting preferential depletion of PO43− relative to nitrogen in rivers. Chemical weathering in the drainage area might explain the high levels of dissolved silicate. Aquaculture ponds contained high concentrations of NH4+ and dissolved organic nitrogen. The particulate phosphorus concentrations in the study area were lower than those reported for estuaries worldwide. The particulate silicate levels in rivers and lagoons were lower than the global average level. Nutrient biogeochemistry in coastal areas was affected by human activities (e.g., aquaculture, agriculture), and by natural phenomena including typhoons. The nutrient concentrations in coastal waters were low because of dispersion of land-derived nutrients in the sea. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes are magnified by estuarine processes (e.g., regeneration, desorption) in estuaries and Laoyehai Lagoon, but not in Xiaohai Lagoon. Riverine and groundwater inputs were the major sources of nutrients to Xiaohai and Laoyehai lagoons, respectively, and riverine inputs and aquaculture effluents were the major sources for the eastern coast of Hainan Island. Nutrient inputs to the coastal ecosystem increased with typhoon-induced runoff of rainwater, elucidating the important influence of typhoons on small tropical rivers.
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Li, R. H., S. M. Liu, Y. W. Li, G. L. Zhang, J. L. Ren, and J. Zhang. "Nutrient dynamics in tropical rivers, estuarine-lagoons, and coastal ecosystems along the eastern Hainan Island." Biogeosciences Discussions 10, no. 6 (June 5, 2013): 9091–147. http://dx.doi.org/10.5194/bgd-10-9091-2013.
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Abstract. Nutrient dynamics were studied along the eastern Hainan Island based on field observations during 2006–2009, to understand nutrient biogeochemical processes and to have an overview of human perturbations on coastal ecosystems in this tropical region. The concentrations of nutrients in the rivers had seasonal variations enriched with dissolved inorganic nitrogen (DIN). High riverine concentrations of nitrate were mainly originated from agricultural fertilizer input. The ratios of DIN : PO43− ranged from 37 to 1063, suggesting preferential PO43− relative to nitrogen in the rivers. The areal yields of dissolved silicate (DSi) varied from 76 to 448 × 103 mol km−2 yr−1 due to erosion over the drainage area, inducing high levels of DSi among worldwide tropical systems. Aquaculture ponds contained high concentrations of NH4&plus; (up to 157 μM) and DON (up to 130 μM). Particulate phosphorus concentrations (0.5 ∼1.4 μM) were in lower level comparied with estuaries around the world. Particulate silicate levels in rivers and lagoons were lower than global average level. Nutrient biogeochemistry in coastal areas were affected by human activities (e.g. aquaculture, agriculture), as well as natural events such as typhoon. Nutrient concentrations were low because open sea water dispersed land-derived nutrients. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes would be magnified by estuarine processes (e.g. regeneration, desorption) in the Wenchanghe/Wenjiaohe Estuary, Wanquan River estuary, and the Laoyehai Lagoon except in the Xiaohai Lagoon. Riverine and groundwater input were the major sources of nutrients to the Xiaohai Lagoon and the Laiyehai Lagoon, respectively. Riverine input and aquaculture effluent were the major sources of nutrients to the eastern coastal of Hainan Island. Nutrient inputs to the coastal ecosystem can be increased by typhoon-induced runoff of rainwater, and phytoplankton bloom in the sea would be caused.
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Mello, Carlos Rogério de, and Nilton Curi. "Hydropedology." Ciência e Agrotecnologia 36, no. 2 (April 2012): 137–46. http://dx.doi.org/10.1590/s1413-70542012000200001.
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Pedology consists of a sub-area of Soil Science that studies the soil and its origin as well as its inter-relationship with the landscape. Hydrology is the science that studies the water in nature in its different mediums (atmosphere, soil and rock), using the watershed as a reference for analysis of the water dynamics and also its interaction with the landscape. The relationship between these two branches of knowledge has been the object of debate and analysis in recent years, contributing to the creation of a multidisciplinary science, which seeks to integrate the respective fields of research. As such, for Hydrology, Pedology has been fundamental for enabling a foundation for the processes associated to the generation of runoff and groundwater recharge, especially concerning the micro-morphological analysis of the soil and the horizons which may impede the water flow, and their relationships with the soil structure. For Pedology, Hydrology can be fundamental to the understanding of the soil formation processes in the different landscapes, in the context of materials deposition as well as the shaping of the relief, as consequence of the soil-climate-drainage interaction, and its importance for pedogenesis. Therefore, the understanding and the deepening of the pedologic analyses, on a microscale and in toposequence in a specific landscape, and its insertion in the theories of Hydrology will allow the development of more realistic, physically based hydrological models and less parameterization dependence, this now being one of the most important challenges for the hydrologist.
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Schaffitel, Axel, Tobias Schuetz, and Markus Weiler. "Fluxes from soil moisture measurements (FluSM v1.0): a data-driven water balance framework for permeable pavements." Geoscientific Model Development 14, no. 4 (April 23, 2021): 2127–42. http://dx.doi.org/10.5194/gmd-14-2127-2021.
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Abstract. Water fluxes at the soil–atmosphere interface are a key piece of information for studying the terrestrial water cycle. However, measuring and modeling water fluxes in the vadose zone poses great challenges. While direct measurements require costly lysimeters, common soil hydrologic models rely on a correct parametrization, a correct representation of the involved processes, and the selection of correct initial and boundary conditions. In contrast to lysimeter measurements, soil moisture measurements are relatively cheap and easy to perform. Using such measurements, data-driven approaches offer the possibility to derive water fluxes directly. Here we present FluSM (fluxes from soil moisture measurements), which is a simple, parsimonious and robust data-driven water balancing framework. FluSM requires only a single input parameter (the infiltration rate) and is especially valuable for cases where the application of Richards-based models is critical. Since permeable pavements (PPs) present such a case, we apply FluSM on a recently published soil moisture data set to obtain the water balance of 15 different PPs over a period of 2 years. Consistent with findings from previous studies, our results show that vertical drainage dominates the water balance of PPs, while surface runoff plays only a minor role. An additional uncertainty analysis demonstrates the ability of the FluSM-approach for water balance studies, since input and parameter uncertainties only have a small effect on the characteristics of the derived water balances. Due to the lack of data on the hydrologic behavior of PPs under field conditions, our results are of special interest for urban hydrology.