Peak Discharge Rate Research Articles

Voluntary co-contraction of ankle muscles alters motor unit discharge characteristics and reduces estimates of persistent inward currents.

Motoneuronal persistent inward currents (PICs) are facilitated by neuromodulatory inputs but are highly sensitive to local inhibitory circuits. Estimates of PICs are reduced by group Ia reciprocal inhibition, and increased with the diffuse actions of neuromodulators released during remote muscle contraction. However, it remains unknown how motoneurons function in the presence of simultaneous excitatory and inhibitory commands. To probe this topic, we investigated motor unit discharge patterns and estimated PICs during voluntary co-contraction of ankle muscles, which simultaneously demands the contraction of agonist-antagonist pairs. Twenty participants performed triangular ramps of both co-contraction (simultaneous dorsiflexion and plantar flexion) and isometric dorsiflexion to a peak of 30% of their maximum muscle activity from a maximal voluntary contraction. Motor unit spike trains were decomposed from high-density surface EMG activity recorded from tibialis anterior using blind source separation algorithms. Voluntary co-contraction altered motor unit discharge rate characteristics. Discharge rate at recruitment and peak discharge rate were modestly reduced (∼6% change; P<0.001; d=0.22) and increased (∼2% change; P=0.001, d=-0.19), respectively, in the entire dataset but no changes were observed when motor units were tracked across conditions. The largest effects during co-contraction were that estimates of PICs (ΔF) were reduced by ∼20% (4.47 vs. 5.57 pulses per second during isometric dorsiflexion; P<0.001, d=0.641). These findings suggest that, during voluntary co-contraction, the inhibitory input from the antagonist muscle overcomes the additional excitatory and neuromodulatory drive that may occur due to the co-contraction of the antagonist muscle, which constrains PIC behaviour. KEY POINTS: Voluntary co-contraction is a unique motor behaviour that concurrently provides excitatory and inhibitory synaptic input to motoneurons. Co-contraction of agonist-antagonist pairs alters agonist motor unit discharge characteristics, consistent with reductions in persistent inward current magnitude.

Optimizing urban green infrastructure using a highly detailed surface modeling approach

Urban trees and forests show a better ecosystem with many benefits, including pure air quality. The development of urban green infrastructure (UGI) creates a better management system that greatly impacts social values in an urban system. The UGI and construction activities are receiving much attention for their effectiveness in addressing various urban ecological, social and economic issues. Using green infrastructure in stormwater management can reduce the influence on urban sewerage systems and, eventually, on building water resources. The main goal of the research is to optimize the green infrastructure to provide a less-pollution, well-organized, and pleasurable environment for the inhabitants. Various models are used to study the present rainfall-runoff scenario, but the stormwater management model (SWMM) is the most preferable and suggested model. Once the parameters are accessed, optimizing the green infrastructure (GI) will be easy. A complete SWMM model is evaluated over the complete surface, and a hydrological measurement is presented. The evaluation study presents various component percentages: asphalt (37%), green (27%), ceiling (21%), grit (12%), and cemented area (2%), which provides rainproof coverage of approximately 60%. A design is developed about the diverse events of GI in urban exploiting the SWMM and demonstrates its stimulus on the rainfall-runoff behaviour. In recent years, very little attention has been given to green spaces in urban areas, which not only increases pollution but also decreases the urbanization. Therefore, urban green spaces are more important to improve air quality and resident living standards. Over the given scenario and the rainfall event, a decline of the quantitative discharge parameters is evident, such as discharge volume (i.e., from 3.6 to 61.8) and the peak discharge rate (i.e., from 5.4 to 62.7%). The simulation results show that green areas give high satisfaction with low construction costs, which shows the superlative performance ratio of the examined measures. From the investigation, it is also recommended to have green areas and public spaces in impervious urban areas, which greatly reduced the runoff in the project area.

Architecture of Fluvial and Deltaic Deposits Exposed Along the Eastern Edge of the Western Fan of Jezero Crater, Mars

AbstractEarly observations from the Perseverance rover suggested a deltaic origin for the western fan of Jezero crater only from images of the Kodiak butte. Here, we use images from the SuperCam Remote Micro‐Imager and the Mastcam‐Z camera to analyze the western fan front along the rover traverse, and further assess its depositional origin. Outcrops in the middle to lower half of the hillslopes comprise planar and inclined beds of sandstone that are interpreted as foresets of deltaic deposits. Foresets are locally structured in ∼20–25 m thick, ∼80–100 m long, antiformal structures interpreted as deltaic mouth bars. Above these foresets, interbedded sandstones and boulder conglomerates are interpreted as fluvial topset beds. One well‐preserved lens of boulder conglomerate displays rounded clasts within well‐sorted sediment deposited in overall fining upward beds. We interpret these deposits as resulting from lateral accretion within fluvial channels. Estimations of peak discharge rates give a range between ∼100 and ∼500 m3 s−1. By contrast, boulder conglomerates exposed in the uppermost part of hillslopes are poorly sorted and truncate the underlying beds. The presence of these boulder deposits suggests that intense sediment‐laden flood episodes occurred after the deltaic foreset and topset beds were deposited, although the origin, timing, and relationship of these boulder deposits to the ancient lake that once filled Jezero crater remains undetermined. Overall, these observations confirm the deltaic nature of the fan front, and suggest a highly variable fluvial input.

Experimental Assessment of Different Air-Based Battery Thermal Management System for Lithium-Ion Battery Pack

&lt;div&gt;Lithium-ion (LI) batteries are widely used to power electric vehicles (EVs), owing to their high charge density, to minimize the environmental pollution caused by fossil fuel-based engines. It experiences an enormous amount of heat generation during charging and discharging cycles, which results in higher operating temperatures and thermal nonuniformity. This affects performance, useful battery life, and operating costs. This can be mitigated by an effective battery thermal management system (BTMS) to dissipate the heat there by safeguarding the battery from adverse thermal effects and ensuring high performance, safety, and longevity of the battery. This article presents a method to estimate the cooling requirement of a given battery pack using calorimetry and discusses the effect of airflow path, flow rate, and inlet air temperature on the thermal behavior of a 4S4P battery pack consisting of 18650 type lithium iron phosphate (LFP) cylindrical Li-ion cells each of 2.55 Ah capacity. In battery pack operation without a cooling system, it is found that the interior cells experience a 3°C higher cell temperature relative to the rest of the battery pack. The cooling performance of the different air BTMS, viz., natural convection cooling, single suction fan cooling, two-fan air cooling, centralized inlet air cooling, and wet jute-based single suction fan air cooling, is discussed. It is observed that the peak temperature rise of the cells in the battery pack was found to be the least in centralized inlet air cooling, unlike other cooling configurations. The wet jute-based single suction fan air cooling is superior by achieving the highest COP of 6, with an 8.9°C rise in battery pack peak temperature for a permissible peak discharge rate. It is observed that the temperature rise of the battery pack is profoundly influenced by the temperature of the inlet air compared to the flow rate.&lt;/div&gt;

SO2 emissions from the Timanfaya eruption (1730–36 CE), Lanzarote, Canary Islands

The 1730–36 CE eruption of Lanzarote (Canary Islands) is the third largest basaltic fissure eruption known to have occurred in the last 1000 years, after the Icelandic events of Laki (1783–84 CE) and Eldgja (939 CE). Approximately 5.2 km3 (1.1 × 1012 kg) of alkalic basalt (sensu lato) lava and pyroclastic rocks were emplaced on land, with a further unknown amount entering the sea, The activity occurred in five eruptive phases from vents situated along a 15-km long, E-W trending fissure. Each phase began with Strombolian fire fountain activity, building large spatter and scoria cones, accompanied and followed by effusive ‘a'ā and pāhoehoe lava flow emplacement. Phases I and II were the most explosive and occurred between 1st September 1730 and June 1731. Samples of scoria and lava surfaces were collected from all phases and the major elements, S, Cl and F contents of matrix glasses and glass inclusions in olivine (the dominant phenocryst phase) were analysed by electron microprobe. Water contents of selected glasses were measured on polished wafers by Fourier Transform Infrared spectroscopy. Glass compositions mimic the range of published whole rock compositions, with Phase I being predominantly basanitic and later phases alkali basalt. Whole rock variations in incompatible trace element ratios are mimicked by ratios involving TiO2, K2O and P2O5 in glass. Matrix and glass inclusion analyses in a given sample are similar, indicating that the inclusions formed synchronously with eruption and that most phenocryst crystallization occurred during earlier evolution of the magmas. Matrix glasses in scoria and surface lava samples have 80–300 ppm S and 260–750 ppm H2O, whereas glass inclusions in olivine have 420–2650 ppm S and 0.1 to 0.5 wt% H2O. Glass inclusions with low sulfur contents were trapped during degassing-induced crystallization as the magma approached the surface. The inclusions with the highest sulfur contents, at given P2O5/TiO2 ratio, are inferred to represent un-degassed melt, and their S content and S/K2O ratios correlate very strongly with incompatible element concentrations and P2O5/TiO2 ratios. The original S contents of 131 matrix glasses were calculated from their P2O5/TiO2 ratios and compared to their measured degassed S contents. The mass of S released per unit mass of magma ranged from about 0.25% in Phase I Episode 1to 0.17% in later phases, with propagated uncertainties of about 2 to 5%. About 40 Mt. of SO2 was released overall, with ca. 25 Mt. being released during the first 5 months of the eruption (Phase I). Estimates of average magma discharge rates imply that plumes remained in the troposphere, with the possible exception of those associated with extreme peak discharge rates during Phase I Episode 1 which may have just reached the upper troposphere – lower stratosphere. Lower eruption rates during the later phases would have confined SO2 emissions to the troposphere. Although acid and sulfate peaks dated to 1730 and 1731 have been reported from some Greenland ice cores, the evidence for stratospheric impact, such as cooling at the Earth's surface and increased stratospheric turbidity, is minimal.

Evaluating soil erosion and runoff dynamics in a humid subtropic, low stream order, southern plains watershed from cultivation and solar farm development

Much work has been done to understand and improve soil and water conservation where agriculture has driven land use intensification. Less is known about soil- and water-related impacts from intensification driven by solar farming, especially at watershed-scales. Here we employed Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) to model Pond Creek, a rural watershed in Texas, USA. Land use is primarily crop cultivation and secondarily pasture for cattle grazing. Presently, several industrial-scale projects are planned to convert ≈15–30% of Pond Creek from agriculture to solar farms. The model was parameterized using public data sources and information from local stakeholders, then calibrated to several historical precipitation events. Experiments were conducted by varying precipitation depth, duration, and land uses: native vegetation pre-cultivation (control), cultivation (current), current conditions with 15% solar farm conversion (solar), and current conditions with 30% solar farm conversion (solar x2). Shifting to solar farming led to significant increases in cumulative sediment load (+12%–30%), with no significant differences in peak discharge rate changes (+0.38%–4%). Comparison to soil loss tolerance values showed current and solar treatment erosion rates exceeded tolerance values between 0.17 and 2.29 tons per hectare and all treatments were significantly different than the native treatment. We discuss high leverage strategies applicable to solar farm development sites as well as watersheds where they reside. Accelerating demand for land for renewable energy such as solar farming warrants greater attention from the soil and water conservation community to anticipate and mitigate impacts across landscapes.

Comparison of on-site versus NOAA’s extreme precipitation intensity-duration-frequency estimates for six forest headwater catchments across the continental United States

Urgency of Precipitation Intensity-Duration-Frequency (IDF) estimation using the most recent data has grown significantly due to recent intense precipitation and cloud burst circumstances impacting infrastructure caused by climate change. Given the continually available digitized up-to-date, long-term, and fine resolution precipitation dataset from the United States Department of Agriculture Forest Service’s (USDAFS) Experimental Forests and Ranges (EF) rain gauge stations, it is both important and relevant to develop precipitation IDF from onsite dataset (Onsite-IDF) that incorporates the most recent time period, aiding in the design, and planning of forest road-stream crossing structures (RSCS) in headwaters to maintain resilient forest ecosystems. Here we developed Onsite-IDFs for hourly and sub-hourly duration, and 25-yr, 50-yr, and 100-yr design return intervals (RIs) from annual maxima series (AMS) of precipitation intensities (PIs) modeled by applying Generalized Extreme Value (GEV) analysis and L-moment based parameter estimation methodology at six USDAFS EFs and compared them with precipitation IDFs obtained from the National Oceanic and Atmospheric Administration Atlas 14 (NOAA-Atlas14). A regional frequency analysis (RFA) was performed for EFs where data from multiple precipitation gauges are available. NOAA’s station-based precipitation IDFs were estimated for comparison using RFA (NOAA-RFA) at one of the EFs where NOAA-Atlas14 precipitation IDFs are unavailable. Onsite-IDFs were then evaluated against the PIs from NOAA-Atlas14 and NOAA-RFA by comparing their relative differences and storm frequencies. Results show considerable relative differences between the Onsite- and NOAA-Atlas14 (or NOAA-RFA) IDFs at these EFs, some of which are strongly dependent on the storm durations and elevation of precipitation gauges, particularly in steep, forested sites of H. J. Andrews (HJA) and Coweeta Hydrological Laboratory (CHL) EFs. At the higher elevation gauge of HJA EF, NOAA-RFA based precipitation IDFs underestimate PI of 25-yr, 50-yr, and 100-yr RIs by considerable amounts for 12-h and 24-h duration storm events relative to the Onsite-IDFs. At the low-gradient Santee (SAN) EF, the PIs of 3- to 24-h storm events with 100-yr frequency (or RI) from NOAA-Atlas14 gauges are found to be equivalent to PIs of more frequent storm events (25–50-yr RI) as estimated from the onsite dataset. Our results recommend use of the Onsite-IDF estimates for the estimation of design storm peak discharge rates at the higher elevation catchments of HJA, CHL, and SAN EF locations, particularly for longer duration events, where NOAA-based precipitation IDFs underestimate the PIs relative to the Onsite-IDFs. This underscores the importance of long-term high resolution EF data for new applications including ecological restorations and indicates that planning and design teams should use as much local data as possible or account for potential PI inconsistencies or underestimations if local data are unavailable.

Forest-cover-loss control on year-round river flow dynamics in the upper Saint John River (Wolastoq) basin, Northeastern North America from 2001 to 2019

Forest-cover removal has led to substantial changes in stream and river flow dynamics globally. The objective of this study was to characterize the daily-to-seasonal forcing of discharge rates in a large, international river in northeastern North America. During a 19-year period (i.e., 2001–2019), forest-cover in the upper Saint John River (Wolastoq) basin was routinely removed as part of large-scale, commercial forestry operations. Annual mean forest-cover removal ranged from 0.39 to 1.35% of basin area, with an obvious increasing trend of 7.7% per year. The long-term annual mean discharge rate at the basin outlet was 457.5 m3 s−1. An analysis based on extreme gradient boosting revealed that daily discharge rates during the snowmelt season were largely influenced by (i) cumulative snow degree-days, as proxy of springtime northeasterly advection of warm-moist air from southerly positions and affiliated increases in snowmelt, (ii) cumulative, on-the-ground snow water equivalent (SWE), and (iii) extent of within-basin, annual forest-cover removal. In contrast, daily discharge rates during the warm period of the year (i.e., June–October) was controlled primarily by warm-season degree-days and annual forest-cover removal. Spring flood maxima increased by 2.1% per year with annual forest-cover loss, whereas mid-summer discharge rates tended to drop. We used wavelet analysis to investigate the role of related environmental variables in controlling river flow dynamics across the time–frequency domain. Annually, the time lag between peak discharge rate and SWE significantly decreased with increasing annual forest-cover removal, suggesting an accelerated melting season. This study has important implications for river flow dynamics in a large river system prone to spring flooding and low waterflow events in summer.

Liquid hydrogen storage system for heavy duty trucks: Capacity, dormancy, refueling, and discharge

Continuing the previous work on configuration, performance, cost, and safety of liquid hydrogen (LH2) storage for Class 8 heavy-duty trucks, we examine and demonstrate the feasibility of meeting the targets of 750 mile (1200 km) driving range, 65 kg H2 storage capacity, 8–10 kg/min refueling rate, 4.6 g H2/s peak discharge rate, 1–3 day dormancy, 5000 refueling cycles, 15% gravimetric capacity, 35 g/L volumetric capacity, and $8/kWh total system cost. A thermodynamic model is developed to determine the useable H2 density considering ullage and LH2 heel subject to heat transfer through the multilayer vacuum insulation and dormancy in the limits of “full” and “empty” fuel tanks. Dynamic simulations are conducted to determine the fraction of gaseous H2 returned to the station Dewar during refueling and heat input by H2 recirculation through an in-tank heat exchanger during discharge. The system gravimetric and volumetric capacities are affected by availability of on-board LH2 pump, discharge pressure, and dormancy. Compared to compressed H2 at 350 and 700 bar in carbon fiber wound Type 4 tanks, LH2 storage in double walled, vacuum insulated, low-pressure Type 1 tanks for heavy duty trucks shows advantages of 34–54% higher useable H2 storage density, 59–68% higher gravimetric capacity, 25–48% higher volumetric capacity, and 36–41% lower cost.

Estimates of persistent inward currents in lower limb motoneurons are larger in females than in males.

Noninvasive recordings of motor unit (MU) spike trains help us understand how the nervous system controls movement and how it adapts to various physiological conditions. The majority of participants in human and nonhuman animal physiology studies are male, and it is assumed that mechanisms uncovered in these studies are shared between males and females. However, sex differences in neurological impairment and physical performance warrant the study of sex as a biological variable in human physiology and performance. To begin addressing this gap in the study of biophysical properties of human motoneurons, we quantified MU discharge rates and estimates of persistent inward current (PIC) magnitude in both sexes. We decomposed MU spike trains from the tibialis anterior (TA), medial gastrocnemius (MG), and soleus (SOL) using high-density surface electromyography and blind source separation algorithms. Ten participants of each sex performed slow triangular (10 s up and down) isometric contractions to a peak of 30% of their maximum voluntary contraction. We then used linear mixed-effects models to determine if peak discharge rate and estimates of PICs were predicted by the fixed effects of sex, muscle, and their interaction. Despite a lack of sex-differences in peak discharge rates across all muscles, estimates of PICs were larger [χ2(1) = 6.26, P = 0.012] in females [4.73 ± 0.242 pulses per second (pps)] than in males (3.81 ± 0.240 pps). These findings suggest that neuromodulatory drive, inhibitory input, and/or biophysical properties of motoneurons differ between the sexes and may contribute to differences in MU discharge patterns.NEW & NOTEWORTHY Sex-related differences in motoneuron analyses have emerged with greater inclusion of female participants, however, mechanisms for these differences remain unclear. Estimates of persistent inward currents (i.e., ΔF) in motoneurons of the lower limb muscles were larger in females than in males. This suggests neuromodulatory drive, monoaminergic signaling, intrinsic motoneuron properties, and/or descending motor commands may differ between the sexes, which provides a potential mechanism underlying previously reported sex-related differences in motoneuron discharge patterns.

Multistate Overflow Fragility Models for Homogenous Inland Levees with Noncohesive Sediments

Existing efforts for analyzing the overflow fragility of inland levees have focused primarily on breach and incorporated simplified definitions of breach for that purpose. The intermediate events that are precursors of a breach have not been analyzed, and several key performance measures including the duration of overflow, discharge rate, and time to the intermediate and breach events, which can inform decisions on evacuation and recovery planning, have not been investigated. This study, for the first time, provides a set of two-dimensional fragility models with an initial water level before surge and peak surge elevation as intensity measures. Fragility models are developed for the class of homogenous levees with noncohesive sediments. Breach formation is modeled through the Dam/Levee Breach model, and failure probabilities are derived using Monte Carlo Simulation (MCS). Unlike existing fragility models, the new class of fragility models accurately represents key performance failure events in levees including initiation of a breach, local geotechnical instabilities, and breach development. These models can be used in risk analysis frameworks to probabilistically account for local geotechnical failures and breach scenarios. Furthermore, probabilistic models for the time of peak discharge rate, breach peak outflow, and volume of water outflow are developed based on stochastic simulations of the flood performance of levees. A power model is investigated for representing breach peak outflow and is compared with previous deterministic models. The proposed model for breach peak outflow can be integrated with hydraulic inundation modeling to probabilistically estimate the inundated area downstream of levees.

A practical method for estimating climate-related changes to riverine flood elevation and frequency

Abstract Floods have been occurring with increasing frequency, leading to damage to communities worldwide. These impacts are expected to continue to rise due to increases in the intensity of extreme rainfall. Global climate model (GCM) output, while imperfect in reproducing daily rainfall, is the only practical source of future projections of extreme rainfall intensification. This article presents a practical method for translating GCM precipitation output into usable outputs for stormwater and flood management planning at a regional or local level. The method estimates the impact of extreme storm intensification on riverine flooding using available runoff estimates from GCM precipitation and variable infiltration capacity models, focusing on changes in elevation and frequency due to climate change. It allows communities and utilities to obtain a screening-level estimate of climate change impacts to peak discharge rate statistics without conducting hydrologic modeling. This article outlines the method, its implementation for the 48 contiguous states of the United States, and an example calculation for a river in the eastern United States. Changes in extreme storm runoff intensity vary significantly by region, but much of the United States is projected to see increases of 25 and 50% by 2060 and 2090, respectively, for the RCP8.5 scenario.

Intrinsic motor neuron excitability is increased after resistance training in older adults.

This study investigated the effects of high-intensity resistance training on estimates of the motor neuron persistent inward current (PIC) in older adults. Seventeen participants (68.5 ± 2.8 yr) completed a 2-wk nonexercise control period followed by 6 wk of resistance training. Surface electromyographic signals were collected with two 32-channel electrodes placed over soleus to investigate motor unit discharge rates. Paired motor unit analysis was used to calculate delta frequency (ΔF) as an estimate of PIC amplitudes during 1) triangular-shaped contractions to 20% of maximum torque capacity and 2) trapezoidal- and triangular-shaped contractions to 20% and 40% of maximum torque capacity, respectively, to understand their ability to modulate PICs as contraction intensity increases. Maximal strength and functional capacity tests were also assessed. For the 20% triangular-shaped contractions, ΔF [0.58-0.87 peaks per second (pps); P ≤ 0.015] and peak discharge rates (0.78-0.99 pps; P ≤ 0.005) increased after training, indicating increased PIC amplitude. PIC modulation also improved after training. During the control period, mean ΔF differences between 20% trapezoidal-shaped and 40% triangular-shaped contractions were 0.09-0.18 pps (P = 0.448 and 0.109, respectively), which increased to 0.44 pps (P < 0.001) after training. Also, changes in ΔF showed moderate to very large correlations (r = 0.39-0.82) with changes in peak discharge rates and broad measures of motor function. Our findings indicate that increased motor neuron excitability is a potential mechanism underpinning training-induced improvements in motor neuron discharge rate, strength, and motor function in older adults. This increased excitability is likely mediated by enhanced PIC amplitudes, which are larger at higher contraction intensities.NEW & NOTEWORTHY Resistance training elicited important alterations in soleus intrinsic motor neuronal excitability, likely mediated by enhanced persistent inward current (PIC) amplitude, in older adults. Estimates of PICs increased after the training period, accompanied by an enhanced ability to increase PIC amplitudes at higher contraction intensities. Our data also suggest that changes in PIC contribution to self-sustained discharging may contribute to increases in motor neuron discharge rates, maximal strength, and functional capacity in older adults after resistance training.

The impact of vegetated landscape elements on runoff in a small agricultural watershed: A modelling study

Flooding of settlements is a growing concern in Europe, also in agricultural areas. Restoration and installation of vegetated landscape elements (vLE) such as hedges, lines of trees and grass buffers, along the parcel boundaries is increasingly recognized as a way to mitigate downstream flood risk. However, there is a lack of scientific evidence to support their implementation. We used the Landlab modelling framework to gain knowledge about the importance of the presence and characteristics of vLEs for the hydrological response in a 26 ha undulating watershed representative for the Belgian loess belt for which a multitude of vLE scenarios were developed. Our model results demonstrated that the total runoff volume, the peak discharge rate and its lag time in such small watersheds are mainly controlled by the density of the vLE objects and their upstream area. First and foremost we demonstrated a negative correlation between the discharge volume and peak discharge rate and the density of the vLE objects and their upstream area. A positive correlation was observed between the lag time and density of the vLE objects for both dry and wet soils and between the lag tag time and upstream area for dry soils. Further, we found that the impact of the value of the saturated hydraulic conductivity of the soil covered by the vLE became increasingly important with increasing soil wetness, with the hydraulic conductivity being negatively correlated with the discharge volume and peak discharge rate. The impact of hydraulic conductivity on the lag time was limited. A negative correlation between hydraulic conductivity and lag time for intermediate wet soils was demonstrated. Our model results also showed that the roughness, expressed as the Manning n-coefficient, of the soil underneath a vLE and the spatial connectivity of the vLE objects have little impact on the hydrological response.

Application of Hydrologic Engineering Centers Hydrologic Modeling System (HEC-HMS) Model for Modelling Flood in Sub Basin of Meenachil River, Kerala, India

Meenachil river basin, located in southern part of Kerala, is frequently liable to flood. It is an area predominant with agricultural land and falls under tropical humid zone. Hence, water resources planning and management and understanding of rainfall-runoff relationship along with its land characteristics, is necessary for irrigation scheduling, flood control and design of various engineering structures. HEC-HMS(Hydrologic Engineering Centers Hydrologic Modeling System) which is a widely used rainfall-runoff model was chosen for the simulation of watershed responses and generation of flood hydrographs. This research was done to establish the peak discharge rate of the river as well as calibrate and validate the HEC-HMS model for the Meenachil subbasin and obtain long-term flow data. The performance parameters NSE (Nash–Sutcliffe model efficiency) coefficient and R² (coefficient of determination) values were obtained above 0.7. The Error in Peak Flow and Volume were calculated below 20%. All these values indicated satisfactory performance of the model simulation both in the calibration (2013-2016) and validation (2017-2018) period. Curve number (61.46-79.93 mm), Initial abstraction(10.29-31.87 mm) and Lag time(208.27 min and 4456.2 min) were found to be the most sensitive parameters of the model. Simulated and observed stream flow values (viz. lowest peak flow of river was found during the year 2013 and it was predicted as 168.9 m³/s and observed as 158.5 m³/s) indicated that the model was able to predict and present credible results for the sub basin.

The effects of α-lactalbumin supplementation and handgrip contraction on soleus motoneuron excitability

We tested two strategies that hypothetically increase serotonin availability (α-lactalbumin consumption and a remote submaximal handgrip contraction) on estimates of persistent inward currents (PICs) amplitude of soleus muscle in healthy participants. With a randomised, double-blind, and cross-over design, 13 healthy participants performed triangular-shaped ramp contractions with their plantar flexors (20% of maximal torque), followed by a 30-s handgrip sustained contraction (40% of maximal force) and consecutive repeated triangular-shaped contractions. This was performed before and after the consumption of either 40g of α-lactalbumin, an isonitrogenous beverage (Zein) or an isocaloric beverage (Corn-starch). Soleus motor units discharge rates were analysed from high-density surface electromyography signals. PICs were estimated by calculating the delta frequency (ΔF) of motor unit train spikes using the paired motor unit technique. ΔF (0.19 pps; p = 0.001; d = 0.30) and peak discharge rate (0.20 pps; p < 0.001; d = 0.37) increased after the handgrip contraction, irrespective of the consumed supplement. No effects of α-lactalbumin were observed. Our results indicate that 40g of α-lactalbumin was unable to modify intrinsic motoneuron excitability. However, performing a submaximal handgrip contraction before the plantar flexion triangular contraction was capable of increasing ΔF and discharge rates on soleus motor units. These findings highlight the diffused effects of serotonergic input, its effects on motoneuron discharge behaviour, and suggest a cross-effector effect within human motoneurons.

Morphometric, Meteorological, and Hydrologic Characteristics Integration for Rainwater Harvesting Potential Assessment in Southeast Beni Suef (Egypt)

In arid areas, the forecast of runoff is problematic for ungauged basins. The peak discharge of flashfloods and rainwater harvesting (RWH) was assessed by the integration of GIS, the RS tool and hydrologic modeling. This approach is still under further improvement to fully understand flashflood and rainwater harvesting potentialities. Different morphometric parameters are extracted and evaluated; they show the most hazardous sub-basins. Vulnerability potential to flooding is high relative to steep slopes, high drainage density, and low stream sinuosity. Using hydrologic modeling, lag time, concentration time, peak discharge rates, runoff volume, rainfall, and total losses are calculated for different return periods. The hydrologic model shows high rainfall rates, and steep slopes are present in the southeastern part of the study area. Low rainfall rates, moderate–high runoff, and gentle slopes are found in the central and downstream parts, which are suitable sites for rainwater harvesting. An analytic hierarchy process is utilized for mapping the best sites to RWH. These criteria use land-cover, average annual max 24 h rainfall, slope, stream order, and lineaments density. About 4% of the basin area has very high potentialities for RWH, while 59% of the basin area has high suitability for RWH. Ten low dam sites are proposed to impact flooding vulnerability and increase rainwater-harvesting potentialities.

Investigating the Influence of Dam-Breach Parameters on Dam-Break Connected Flood Hydrograph

The dam-break connected flood hydrograph properties primarily depend on the breach geometry and the time for the breach to fully develop. Therefore, the prediction of dam’s breach geometry is essential in dam-break studies. To understand the impact of breach parameters on flood peak hydrograph, five of the most common breach prediction methods are implemented in the presented study to estimate the flood hydrographs using 2-dimensional HEC-RAS model. The Ürkmez Dam is chosen as the case study due to the presence of a residential settlement located right at the dam downstream where undesirably any breach of the dam body can have inevitable and dramatical risks on downstream populations and properties. Various levels for reservoir storage are investigated in each method. In order to assess the impact of each breach parameter on the resulting flood hydrographs, sensitivity analysis is carried out. The peak discharge rates and the times to peak for each analyzed scenario are investigated and discussed. Results reveal that Froehlich approach is the most reasonable method for estimating dam-breach parameters as far as exemplified in the Ürkmez Dam case. Furthermore, sensitivity analysis points out that the parameter of the breach side slope has no major influence on the time to peak while having an insignificant impact on the peak discharge. Besides, the study exhibits that both the peak discharge and the time to peak characteristics are highly sensitive to breach time formation parameter. In the light of these targeted findings, the study is aimed to contribute to other relevant research in designating the set of key parameters in experimental or modeling efforts in a way to limit the uncertainty that substantially originates from personal judgment.

Flash Flood Assessment and Management for Sustainable Development Using Geospatial Technology and WMS Models in Abha City, Aseer Region, Saudi Arabia

Abha city is distinguished by urbanization, infrastructure, deepening watercourses, and changes in runoff flow which encourage flash floods in the urban zones of many villages in the region. AlMahalah village is prone to flash flooding due to its geographic location near the outlet of convergence streams of significant flow. The Geographic Information System (GIS), Remote Sensing (RS), Water Modeling System (WMS), and Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) were used to assess the effects of flash floods on AlMahala village. Precipitation data from 1978 to 2020 was statistically processed and analysed to provide more information about flash flood hazards. With a 3-h lag time in both watersheds, the higher peak discharge in Wadi Abha than in Wadi Al Akkas indicates that flooding was a primary concern in Wadi Abha. With an average yearly rainfall of 520 mm, the hydrograph simulation from 1 to 5 April 2020 would contribute to the junction (outlet) point of AlMahala village with a peak discharge rate of 474.14 m3/s. The vegetation cover increased by 243 km2 in 2020 compared to 2016. The HEC-RAS model was used to calculate the water depth, velocity, and elevation of the water surface with and without dam installation. The study provides the administration with practical and reasonable procedures for avoiding flash flood destruction in urban areas.

A distributed domain model coupling open channel flow and groundwater flow to quantify the impact of lateral hydrologic exchange on hydrograph

• A distributed-domain coupling model is developed to evaluate the interaction between hydrologic exchange flows and river hydrodynamics. • The buffering effect of lateral HEFs can dominate flood wave patterns. • The falling limb (with a power-law rate) of hydrographs is linked to spatially heterogeneous hydraulic properties. Hydrologic exchange flows (HEFs) of river-aquifer systems are known to affect water flow, but the quantitative influences of lateral HEFs and the riparian zone’s hydraulic conductivity ( K ) distribution on stream fluxes remain obscure under varying hydrologic conditions. To fill this knowledge gap, this study proposed a physical based, distributed domain, coupled (open channel and groundwater) flow model (DDCM) to quantify the effect of lateral HEFs on hydrograph characteristics, including especially the peak discharge and tailing decay which are practically important. Numerical experiments showed that (1) the interaction between the lateral HEFs and river hydrodynamics reduced the peak discharge and flood flow rates, (2) a heterogeneous K field of the riparian zone generated multi-rate HEFs (which then changed flow response) represented by the hydrographs with various declining rates (varying from exponential to power-law), significantly expanding the flow process, and (3) the probability density function of K also affected the tailing and peak of the hydrograph. A preliminary test showed that the DDCM captured the overall pattern of hydrographs observed from a catchment in the Wadi Ahin West, Oman. This study, therefore, provided a model-based quantification of the mechanisms and factors of the lateral HEFs affecting the hydrograph pattern in flood events, and further applications are needed to test the applicability of the DDCM in capturing real-world hydrographs affected by the lateral HEFs.