Display omitted
•Monitored rainfall-runoff responses from 13 urban and two forested watersheds.•Statistically compared measurements to current and novel hydrologic design models.•Greater uncertainty ...in peak flow predictions compared to runoff volume.•Different design models necessary for specific watershed / rainfall characteristics.
The need for resilient stormwater infrastructure is increasingly critical as urbanization and climate change continue to threaten water resources. Engineers and practitioners require reliable methodologies to estimate rainfall-runoff responses to adequately size and design sewer pipes and inlets, flood controls, and stormwater control measures (SCMs). The National Resource Conservation Service Technical Release 55 (often referred to as curve number CN method), Simple, and Rational methods are methodologies commonly implemented for such designs by regulatory agencies due to the limited inputs needed to estimate runoff; however, uncertainty is present in each model since they simplify actual hydrological processes. In this study, 13 urban and two forested watersheds were monitored, and their observed hydrologic responses were compared to modeled hydrologic responses utilizing the aforementioned methods. Significant differences in observed normalized runoff volumes (i.e., runoff coefficients) and normalized peak flow rates were found between watersheds with similar watershed characteristics and rainfall patterns, demonstrating the meticulous model inputs required to differentiate hydrologic responses between similar watersheds. A suite of alternative predictive models, informed by feature selection algorithms, were formulated and compared to the performance of standard methods. Results suggested that composite CN methods were the best predictors of event runoff volume across all watersheds (Nash Sutcliffe NSE and Kling Gupta Efficiencies KGE of 0.74 and 0.52, respectively), but were outperformed by the Simple method for watersheds with more than 45% impervious cover (NSE and KGE scores of 0.85 and 0.76, respectively). However, composite CN methods underestimated runoff volume from every watershed, a limitation that was intended to be addressed through the creation of the distributed CN method. In the distributed approach, runoff volume estimations were improved compared to the composite CN approach only when directly connected impervious area in the watershed was extremely high or extremely low. The multi-linear regression runoff volume model created herein did not outperform traditional runoff models except when rainfall depth was less than 12.5 mm (i.e., the storms for which traditional runoff volume estimation methods performed the worst). Uncertainty in modeled peak flow rate was substantially greater than for runoff volume (NSE and KGE scores between 0.48 – 0.55 and 0.39 – 0.67, respectively) across all methodologies. There is a continued need to develop more dependable estimates of peak flow which are critical to the design of pipes, flood routing, and hydrograph prediction. Overall, these results suggest one model is not optimal in all scenarios. Municipalities, regulatory agencies, and stormwater engineers should consider the adoption of multiple methodologies and use guidance from the results herein to provide recommendations as to when each model is most applicable.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The calculation of peak discharge in non-instrumented basins requires including morphometric parameters, which in turn depend on the map type used. This study analyses the impact of and variation in ...peak discharges of the Caño Ricaurte basin, Colombia, based on three types of maps at different resolution scales. The reference map used was the map made for the detailed designs of the channel analysed, which was extracted from the Master Plan of the City. Additionally, maps from a 90 × 90 m digital elevation model and contour lines extracted from Google Earth were used. The time of concentration was determined by different equations (Kirpich, Témez, Bureau, and TR-55) using the mapping methods described above, and the peak discharge was determined using rainfall-runoff models.
•Spring freshet peak flow can be estimated with few variables, easily available.•Generalized Additive Model (GAM) provided a reliable 24-h forecast of the peak flow value.•GAM model forecasts ...compared favorably to a more complex deterministic hydrological model.•The forecasted flow can be used as a decision support to launch emergency measures.
In cold boreal regions, for rivers with small to medium-sized watersheds under natural hydrological regimes, the risk of spring flooding is determined by peak flow intensity rather than flood volume. Nonetheless, short-term forecasting of peak flow intensity is subject to a lot of uncertainty and depends largely on ongoing specific snowmelt conditions. This study proposes a simple operational model based on the Generalized Additive Model (GAM) to forecast short-term spring freshet peak flow. The model uses hydrological and meteorological data publicly available on a daily basis. The model was tested on five rivers in the Province of Québec (Canada) with drainage basins varying between 350 km2 and 1707 km2. The model results (forecasted peak flows) were compared to those obtained using the Generalized Linear Model (GLM) and a distributed deterministic hydrological model (Hydrotel) currently used for flow forecasting of several rivers in the Province. The peak flow was forecasted accurately with relatively few variables, mainly a combination of river flow and rate of flow increase a few days before peak flow, previous air temperature, rain accumulation and snow accumulation. Nonetheless, the best combinations of predictive variables were river-specific. The GAM model, using an automatic fitting and easily accessible daily data, can be implemented by any stakeholder.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Develops and evaluates a practical temporal disaggregation approach that combines daily observations and reanalysis sub-daily rainfall.•Disaggregated rainfall reduces false alarms but shows mixed ...performance in reproducing fine-scale rainfall statistics.•The disaggregation approach improves the hydrological simulation of large flows.
Accurate rainfall datasets with high temporal and spatial resolutions are crucial for most hydrological applications. One potentially valuable source of rainfall data that has consistent spatial and temporal resolutions are atmospheric reanalysis products. However, while such data sets can provide a physically consistent representation of rainfall over large spatial and temporal extents, they are generally less accurate than observed datasets at daily scales. In contrast, while the gauge measurements are accurate source of rainfall data, sub-daily observations are spatially sparse and are of shorter length than daily observations. While the temporal resolution of daily observations can be enhanced using temporal disaggregation methods, they are often applied stochastically with a focus on capturing the fine-scale statistical properties rather than generating a best estimate time series useful for hindcasting purposes. The increasing availability of high resolution regional reanalysis products prompts the question whether they can be used to temporally disaggregate daily observations to derive high-resolution estimates of sub-daily rainfalls suitable for hydrologic applications. This study investigates the efficacy of a simple disaggregation approach to temporally disaggregate daily rainfalls to hourly values using a regional reanalysis at moderate spatial resolutions. The approach is tested on attributes relevant to a wide range of hydrological applications. The selected performance metrics include the distribution and frequency of various sub-daily rainfall accumulations, statistics characterising the sequencing and central tendency of sub-daily rainfalls, and the efficacy of areal estimates of sub-daily rainfalls for simulating catchment streamflows. Categorical evaluation shows that the disaggregated rainfalls reduce the frequency of false alarms and improves the probability of detection compared to the use of raw reanalysis estimates. However, a mixed performance in capturing fine-scale statistical characteristics suggests that the disaggregation approach is less robust for applications that rely solely on high-resolution rainfall characteristics. In hydrological evaluation, when compared to estimates based on raw reanalysis or uniformly disaggregated daily observations, the disaggregated catchment rainfalls improve the simulation of the magnitude and timing of peak flows, and the accuracy of derived flood frequency estimates. The proposed disaggregation method is easily applied to any high-resolution dataset and has the potential to be used in hydrological applications that rely heavily on sub-daily characterisation, with a varying performance across the target applications.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•The cough peak flow measurement has high measurement reliability in patients with myasthenia gravis (MG) before and after immunotherapy.•Cough peak flow measurement is correlated with respiratory ...function and MG symptoms.•Cough peak flow measurement is a useful self-monitoring tool for MG symptoms.
Decreased cough strength in myasthenia gravis (MG) leads to aspiration and increases the risk of MG crisis. The aim of this study was to clarify the reliability and validity of cough peak flow (CPF) measurements in MG. A total of 26 patients with MG who underwent CPF measurements using the peak flow meter by themselves were included. MG symptoms were evaluated by pulmonary function tests and clinical MG assessment scales before and after immune-treatments. The relationship between CPF and pulmonary function tests and MG comprehensive were assessed. The cut-off value of CPF for aspiration risk was determined and the area under the curve (AUC) was calculated. The intraclass correlation coefficient was more than 0.95 for pre-and post-treatment. Positive correlations were found between CPF and almost all spirometric values as well as between the differences of pre-and post-treatment in CPF and quantitative myasthenia gravis score. The CPF for identifying the aspiration risk was used to calculate the CPF cut-off value of 205 L/min with a sensitivity of 0.77, specificity of 0.90, and AUC of 0.85. The CPF, a convenient measure by patients themselves, has a high reliability in patients with MG, and is a useful biomarker reflecting MG symptoms.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Cover crops and surface soil are sources of P to runoff over non-growing season.•Wheat residue does not release significant quantities of P to runoff.•Most P released by residues and soil retained ...on field.•Edge of field losses of P much smaller than P pools in soil and residues.•Cover crops in low-lying areas prone to inundation at greater risk for P leaching.
In northern climates, crop residue and cover crops are potential sources of dissolved reactive phosphorus (DRP) to runoff; yet, there are few field studies to quantify this. The objectives of this study were (1) to quantify changes in water extractable phosphorus (WEP) concentrations in the residues of Triticum aestivum L. (winter wheat), Trifolium pretense L. (red clover) and Avena sativa L. (oat) cover crops and surface soil in two agricultural fields (ILD and LON) over the non-growing season (NGS); and (2) to determine if changes in WEP in vegetation residue or soil were reflected in loads of DRP or total P (TP) in surface runoff and/or tile drain effluent. Concentrations of WEP in cover crops were larger than those in wheat residue and soil. Water extractable P concentrations in vegetation increased with plant decomposition and decreased following runoff events indicating that the plant WEP was mobilized in runoff. Differences in WEP concentrations were not observed with topography, with the exception of the period following snowmelt when low-lying areas prone to surface inundation were depleted relative to upland locations. Although WEP appeared to have been mobilized from vegetation and soil pools, loads of DRP (0.165–0.245kgha−1) and TP (0.295kgha−1–0.360kgha−1) leaving the fields were small in comparison to P pools in cover crops (7.70kgha−1 oat, 1.70kgha−1 red clover), wheat residues (0.03–0.06kgha−1) and soils (1.39–5.87kgha−1), suggesting that much of the P released from vegetation was retained within the field. This study provides insight into the timing and magnitude of P release from vegetation throughout the non-growing season in regions with cool temperate climates, and provides an improved understanding of the contribution of cover crops to winter P losses.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Introduction:A better understanding of the cerebrospinal fluid (CSF) flow dynamics of Chiari 1 malformation (CM-1) may help to reach more specific parameters for indicating therapy and response to ...therapy. This study developed a parameter to better characterize CSF flow alterations in the cerebral aqueduct in patients presenting with CM-1.Methods:We retrospectively scanned archives for CM-1 patients who underwent CSF flow analysis between January 2016 and December 2022. Eighty-eight CM-1 patients and 83 control cases were included in the study. The cerebellar tonsillar descensus was measured in all patients. In 11 cases with the syrinx cavity, the largest transverse diameter of the cavity was measured. Phase-contrast magnetic resonance imaging was performed using a 1.5 T scanner. Peak velocity (P-Vel) (cm/s), average velocity (A-Vel) (cm/s), forward flow volume (μL), reverse flow volume (μL), peak flow (P-Fl) (mL/s), and time to peak velocity (TP-Vel) (s) and cerebral aqueduct’s stroke volume (μL) were calculated. Sixteen CM-1 patients underwent decompression surgery, and we examined postoperative CSF flow analyses.Results:A-Vel and P-F1 were statistically significantly higher in CM-1 cases than in controls (p=0.006, p=0.037). There was a significant negative correlation between the diameter of the syrinx cavity and P-Vel and P-Fl, and a positive correlation between TP-Vel. We found no significant difference between the postoperative and preoperative CSF flow parameters of the CM-1 patients.Conclusion:P-Fl differs between the patient and control groups and correlates with the syrinx diameter; therefore, it could be a useful parameter in CSF flow analysis in CM-1 cases. However, higher case numbers can achieve more effective results.
This study presents a global real-time control (RTC) approach for sustainable and adaptive management of stormwater. A network of inter-connected devices are assumed to dynamically generate the ...required set-points for the system actuators at the remote control center where global optimization algorithms calculate real-time operational decision-making target values. These target values activate the local controllers to manipulate the spatially distributed detention basin's outlets enabling a smart catchment scale optimal control. A real world watershed with four outlets to a nearby watercourse is chosen to test the applicability and efficiency of the proposed dynamic control approach, based on model simulation results. Results show that the proposed autonomous control approach has the ability to enhance the global performance of the stormwater management system in terms of quality and quantity to balance the network flow dynamics and environmental demands, while reducing the potential for erosion of receiving water bodies. Climate change is specifically discussed as a challenge for the designed control framework. Although, the performance criteria are shown to be affected by the increased rainfall intensities compared to actual rainfall scenarios, the proposed methodology still improves the peak flow reduction and detention time of water, at global scale, up to 54% and 14 h respectively under climate change conditions.
•A smart control framework is proposed for system-level management of urban stormwater.•The developed integrated optimization model enables an optimized flow planning that minimizes peak-flows and maximizes the detention time of water in the basins.•A dynamically controlled stormwater management system performs in line with the sustainability and resiliency of smart cities.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Uniform rainfall created smallest peak flows in all rainfall patterns.•Late peak rainfall produced highest flow, followed by middle and early patterns.•Land cover in sensitive areas under middle and ...late rain peaks impacted flow most.•Land-cover change effects on flood peaks were proportionally smaller for heavy rain.•Absolute flow peak change led by land-cover change became larger for heavy rain.
Flood processes in catchments are driven by a combination of rainfall and landscape characteristics. Upland peatlands are source areas of flooding but there is lack of understanding of how different rainfall intensities and temporal patterns may interact with land-cover configurations to influence flood peaks. Using spatially distributed (SD-) TOPMODEL we investigated these interactions for a case study peatland catchment. For each of four rainfall depths ranging from 20 mm to 50 mm, four storm rainfall patterns were applied (rainfall that was uniform, rainfall with an early peak intensity during the storm, middle peak and late peak). Late peak rainfall resulted in the highest river flow peaks at the catchment outlet studied, followed by middle and early rainfall peak patterns, while uniform rainfall through time gave the lowest flow peaks. A key factor was synchroneity of overland flow movement and concentration. The impact on river flow peaks of land-cover change on riparian zones and on gentle gradient slopes was larger than that for other parts of the catchment under different rainfall intensities and patterns. The impacts of land-cover change on proportional change in flood peaks in these sensitive areas became smaller when rainfall intensity increased, but absolute changes in flow peaks became larger. Land-cover change in sensitive areas under middle and late peak rainfall had a larger impact on river flow peaks than for early peak rainfall. It was possible to identify the ‘worst’ rainfall patterns for a particular case of land-cover change which may be useful for practitioners to help manage expectations of flood response to nature-based solutions.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The process of identifying the peak discharge using the rational method was introduced in the 1880s. This method is a simple procedure for determining the peak discharge derived from surface runoff ...flow. Therefore, this research modified a simple hydrological formulation (rational method) based on fieldwork and compared a numerical rainfall model to the relationship model by using the simulation parameters, namely rainfall, infiltration, land use, and stream for hydrological conditions. The novelty of this research is a modification of the theoretical formula (rational method) through the use of fieldwork factors to modify the run-off coefficient. The first scene-up was overlay mapping between land and land use shape files, while the scene-up sampling point was upstream and downstream. This was continued with the estimation curve number until a specific composite curve number was initiated. The rate of infiltration was determined using the Horton method to distinguish the soil type, while the Water Stage Data Logger Starter Kit 13" HOBO KIT-S-U20-04 was used to measure the water level, HEC HMS, and rating curve analysis. The relationships between the fieldwork data using hydrology analysis and modeling were then compared. The results showed that the maximum rainfall calculated and analyzed from the box-and-whisker plot was 140 mm in the year 2019. In addition, the infiltration rate at the upstream and downstream areas was 90 mm/hour and 26.4 mm/hour, or 30% out of the upstream area value. Finally, the estimations of the runoff coefficient were 0.60, 0.45, and 0.0133, while the discharges for the maximum rainfall intensity were observed at 405.7 m3/s, 304.3 m3/s, and 25 m3/s. The simulation using Hydrological Modelling HEC HMS 4.11 computed results of 0.1 m3/s and observed flow of 0.3 m3/s. Doi: 10.28991/HEF-2023-04-02-02 Full Text: PDF
PDF
