Changes In Peak Flow Research Articles

Forecasting the impacts of future development on water quantity and quality within the Reedy River Watershed

This study was initiated to gain a better understanding of how patterns of development within Greenville, SC and its surrounding metro area would affect the Reedy River's water quantity and quality. Grenville County is located in the Upstate of South Carolina and serves as an economic hub for this region. Greenville is located on the I-85 corridor halfway between Atlanta, GA and Charlotte, NC. A previously prepared watershed-scale model was modified to yield quantity and quality data that would result from projected growth in Greenville through year 2030 at three different growth scenarios.The major findings of the study showed water quality was degraded with higher nutrient loads and peak and average flows were consistently higher for sprawling as compared to compact development. As more land is developed in the sprawling scenario, the amount of stormwater increases while water quality decreases. At Boyd Millpond by 2030, for instance, change in peak flow and average flow percentages more than double for the sprawling scenario. Similar effects were also seen for both total phosphorus and total nitrogen levels. Results are similar by 2030 for the flow entering Lake Greenwood from the Reedy River Arm. At that location, change in peak and average flow percentages, and changes in total nitrogen and phosphorus percentages, more than double when comparing sprawling versus compact developments.While these results are based on the effects of predicted development along the Reedy River, in Greenville, SC, the overall implications of development on water quality applies to most any community faced with similar issues. These modeling results allow land use planners such as municipal boards to gain a better understanding of what impacts land use planning and zoning can have on a community as related to effects on water quality and quantity.

Pediatric stroke and transcranial direct current stimulation: methods for rational individualized dose optimization.

Background: Transcranial direct current stimulation (tDCS) has been investigated mainly in adults and doses may not be appropriate in pediatric applications. In perinatal stroke where potential applications are promising, rational adaptation of dosage for children remains under investigation.Objective: Construct child-specific tDCS dosing parameters through case study within a perinatal stroke tDCS safety and feasibility trial.Methods: 10-year-old subject with a diagnosis of presumed perinatal ischemic stroke and hemiparesis was identified. T1 magnetic resonance imaging (MRI) scans used to derive computerized model for current flow and electrode positions. Workflow using modeling results and consideration of dosage in previous clinical trials was incorporated. Prior ad hoc adult montages vs. de novo optimized montages provided distinct risk benefit analysis. Approximating adult dose required consideration of changes in both peak brain current flow and distribution which further tradeoff between maximizing efficacy and adding safety factors. Electrode size, position, current intensity, compliance voltage, and duration were controlled independently in this process.Results: Brain electric fields modeled and compared to values previously predicted models (Datta et al., 2011; Minhas et al., 2012). Approximating conservative brain current flow patterns and intensities used in previous adult trials for comparable indications, the optimal current intensity established was 0.7 mA for 10 min with a tDCS C3/C4 montage. Specifically 0.7 mA produced comparable peak brain current intensity of an average adult receiving 1.0 mA. Electrode size of 5 × 7 cm2 with 1.0 mA and low-voltage tDCS was employed to maximize tolerability. Safety and feasibility confirmed with subject tolerating the session well and no serious adverse events.Conclusion: Rational approaches to dose customization, with steps informed by computational modeling, may improve guidance for pediatric stroke tDCS trials.

Change detection of storm runoff and sediment yield using hydrologic models following wildfire in a coastal redwood forest, California

This study attempted to detect changes in stormflow volumes, peakflows, and sediment loads using hydrologic models within the context of an uncertainty assessment following wildfire. In 2009, after 8 years of study, the Lockheed Fire burned the treatment and control watersheds of a paired watershed study in coastal California, USA, eliminating the ability to continue a paired watershed before–after control–intervention (BACI) study design. An alternative analysis was used to detect stormflow and sediment load changes due to the wildfire by comparing measured posttreatment stormflow and sediment load with simulated predisturbance responses predicted with the hydrologic models HBV-EC and DHSVM. High natural variability of stormflow and sediment measurements compounded with uncertainty associated with the hydrologic models and climate suggest that only large changes can be detected. The fire and subsequent salvage harvest created an approximately 9%–12% reduction in forest overstory canopy and a 70%–90% consumption of understory vegetation. No discernible changes in slopes of regression lines were detected between predisturbance and postfire stormflow volumes, peakflows, or sediment loads. No changes were detected in stormflow volume, peakflow, or sediment loads comparing pre- and post-fire vegetation inputs to the hydrologic model DHSVM. The lack of detected change in streamflow to accelerate stream channel erosion combined with low to moderate fire severity adjacent to stream channels most likely were the reasons for no detected postfire change to sediment loads.

Physiology-based minimum clinically important difference thresholds in adult laryngotracheal stenosis.

Delivering evidence-based patient care is predicated on the availability of objective and validated outcome measures. We aimed to calculate physiology-based minimum clinically important difference (MCID) values for adult laryngotracheal stenosis (LTS). Prospective observational study. Patient demographics, morbidities, and stenosis severity were assessed preoperatively. Flow-volume loops and Medical Research Council (MRC) dyspnea grades were measured in 21 males and 44 females before and 6 to 8 weeks after airway surgery, and before treating recurrent disease in 10 patients. Anchor and distribution-based methodologies were used to calculate MCIDs for treatment efficacy and disease recurrence respectively. The mean age at treatment was 46 ± 16 years. The most common etiology was idiopathic subglottic stenosis (38%). Most lesions (66%) obstructed >70% of the lumen. There were strong correlations between treatment-related changes in total peak flow (TPF) (ΔTPF) (peak expiratory flow + |peak inspiratory flow|) and the ratio of area under the flow-volume loop (AUC) to forced vital capacity (FVC) (ΔAUCTotal /FVC), and treatment-related changes in the MRC grade (ΔMRC) (r = -0.76 and r = -0.82, respectively). Both TPF and AUCTotal /FVC discriminated between effective (ΔMRC <0) and ineffective (ΔMRC ≥0) interventions, yielding MCID values of 4.2 L/s for TPF and 2.1 L(2) /s for AUCTotal /FVC, respectively. Ten patients required airway treatment for recurrent disease, and TPF and AUCTotal /FVC levels had distribution-based MCID values of 0.9 and 0.6, respectively. Flow-volume loops provide a quantitative method of objectively assessing outcomes in LTS. TPF is the most convenient index for this purpose, but AUCTotal /FVC provides marginally greater sensitivity and specificity.

Climate changes of hydrometeorological and hydrological extremes in the Paute basin, Ecuadorean Andes

Abstract. Investigation was made on the climate change signal for hydrometeorological and hydrological variables along the Paute River basin, in the southern Ecuador Andes. An adjusted quantile perturbation approach was used for climate downscaling, and the impact of climate change on runoff was studied for two nested catchments within the basin. The analysis was done making use of long daily series of seven representative rainfall and temperature sites along the study area and considering climate change signals of global and regional climate models for IPCC SRES scenarios A1B, A2 and B1. The determination of runoff was carried out using a lumped conceptual rainfall–runoff model. The study found that the range of changes in temperature is homogeneous for almost the entire region with an average annual increase of approximately +2.0 &amp;amp;degC. However, the warmest periods of the year show lower changes than the colder periods. For rainfall, downscaled results project increases in the mean annual rainfall depth and the extreme daily rainfall intensities along the basin for all sites and all scenarios. Higher changes in extreme rainfall intensities are for the wetter region. These lead to changes in catchment runoff flows, with increasing high peak flows and decreasing low peak flows. The changes in high peak flows are related to the changes in rainfall extremes, whereas the decreases in the low peak flows are due to the increase in temperature and potential evapotranspiration together with the reduction in the number of wet days.

On the utilization of hydrological modelling for road drainage design under climate and land use change

Road drainage structures are often designed using methods that do not consider process-based representations of a landscape's hydrological response. This may create inadequately sized structures as coupled land cover and climate changes can lead to an amplified hydrological response. This study aims to quantify potential increases of runoff in response to future extreme rain events in a 61km2 catchment (40% forested) in southwest Sweden using a physically-based hydrological modelling approach. We simulate peak discharge and water level (stage) at two types of pipe bridges and one culvert, both of which are commonly used at Swedish road/stream intersections, under combined forest clear-cutting and future climate scenarios for 2050 and 2100. The frequency of changes in peak flow and water level varies with time (seasonality) and storm size. These changes indicate that the magnitude of peak flow and the runoff response are highly correlated to season rather than storm size. In all scenarios considered, the dimensions of the current culvert are insufficient to handle the increase in water level estimated using a physically-based modelling approach. It also appears that the water level at the pipe bridges changes differently depending on the size and timing of the storm events. The findings of the present study and the approach put forward should be considered when planning investigations on and maintenance for areas at risk of high water flows. In addition, the research highlights the utility of physically-based hydrological models to identify the appropriateness of road drainage structure dimensioning.

Parsimonious rainfall-runoff model construction supported by time series processing and validation of hydrological extremes – Part 2: Intercomparison of models and calibration approaches

An intercomparison of different approaches for the construction and calibration of lumped conceptual rainfall-runoff models is made based on two case studies with unrelated meteorological and hydrological characteristics located in two regions, Belgium and Kenya. While a model with pre-fixed “one-size-fits-all” model structure is traditionally used in lumped conceptual rainfall-runoff modeling, this paper shows the advantages of model structure inference from data or field evidence in a case-specific and step-wise way using non-commensurable measures derived from observed series. The step-wise model structure identification method does not lead to higher accuracy than the traditional approach when evaluated using common statistical criteria like the Nash–Sutcliffe efficiency. The method is, however, favorable to produce a well-balanced calibration obtaining accurate results for a wide range of runoff properties: total flows, quick and slow subflows, cumulative volumes, peak flows, low flows, frequency distributions of peak and low flows, changes in quick flows for given changes in rainfall. It furthermore is shown that model performance evaluation procedures that account for the flow residual serial dependency and homoscedasticity are preferred. Explicit evaluation of model results for peak and/or low flow extremes and changes in these extremes make the models useful for impact investigations on such hydrological extremes.

Multi-decadal variations in annual maximum peak flows in semi-arid and temperate regions of Chile

In determining the possible influence of climate change, it is important to understand the temporal and spatial variability in streamflow response for diverse climate zones. Thus, the aim of this study was to determine the presence of changes in annual maximum peak flow for two climate zones in Chile over the past few decades. A general analysis, a flood frequency analysis and a trend analysis were used to study such changes between 1975 and 2008 for a semi-arid (29°S–32°S) and a temperate (36°S–38°S) climatic zone. The historic annual maxima, minima and mean flows, as well as decadal mean peak flow, were compared over the period of record. The Gumbel distribution was selected to compare the 30-year flood values of two ±15-year intervals, which showed that streamflow decreased by an average of 19.5% in the semi-arid stations and increased by an average of 22.6% in the temperate stations. The Mann-Kendall test was used to investigate the temporal changes in streamflows, with negative trends being observed in 87% of the stations analysed in the semi-arid zone, and positive trends in 57% of those analysed in the temperate zone. These differences in streamflow response between climate zones could be related to recent documented increases in altitude of the zero-degree isotherm in the Andes Mountains of Chile, since most of the significant positive and negative changes were detected in first-order rivers located closer to this mountain range.Editor D. Koutsoyiannis; Associate editor H. LinsCitation Pizarro, R., Vera, M., Valdés, R., Helwig, B., and Olivares, C., 2013. Multi-decadal variations in annual maximum peak flows in semi-arid and temperate regions of Chile. Hydrological Sciences Journal, 59 (2), 300–311.

Influence of peak flow changes on the macroinvertebrate drift downstream of a Brazilian hydroelectric dam.

Successive daily peak flows from hydropower plants can disrupt aquatic ecosystems and alter the composition and structure of macroinvertebrates downstream. We evaluated the influence of peak flow changes on macroinvertebrate drift downstream of a hydroelectric plant as a basis for determining ecological flows that might reduce the disturbance of aquatic biota. The aim of this study was to assess the influence of flow fluctuations on the seasonal and daily drift patterns of macroinvertebrates. We collected macroinvertebrates during fixed flow rates (323 m3.s-1 in the wet season and 111 m3.s-1 in the dry season) and when peak flows fluctuated (378 to 481 m3.s-1 in the wet season, and 109 to 173 m3.s-1 in the dry season) in 2010. We collected 31,924 organisms belonging to 46 taxa in the four sampling periods. Taxonomic composition and densities of drifting invertebrates differed between fixed and fluctuating flows, in both wet and dry seasons, but family richness varied insignificantly. We conclude that macroinvertebrate assemblages downstream of dams are influenced by daily peak flow fluctuations. When making environmental flow decisions for dams, it would be wise to consider drifting macroinvertebrates because they reflect ecological changes in downstream biological assemblages.

Prioritization of subwatersheds based on flooding conditions using hydrological model, multivariate analysis and remote sensing technique

AbstractPrioritization of watersheds has gained more importance in natural resources management, particularly in the context of watershed management. Flooding potential is one of the main indices used to prioritize watersheds. The objective of this study is to investigate the Pol‐Doab Shazand Watershed flooding conditions as a result of land use change and prioritization of its subwatersheds using rainfall – runoff data. For this purpose, after computation of design flow with different return periods, factor analysis technique was applied to determine the best flow with proper return period towards evaluation and prioritization of subwatersheds. The results showed that the design flow with 25‐year return period (Q25) is suitable. The results indicate that subwatershed 22 is the highest priority because of large changes in peak flow, and subwatershed 2 given the lowest priority since changes in peak flow is the lowest.

The effect of diaphragm contraction on upper airway collapsibility

Increasing lung volume increases upper airway patency and decreases airway resistance and collapsibility. The role of diaphragm contraction in producing these changes remains unclear. This study was undertaken to determine the effect of selective diaphragm contraction, induced by phrenic nerve stimulation, on upper airway collapsibility and the extent to which any observed change was attributable to lung volume-related changes in pressure gradients or to diaphragm descent-related mediastinal traction. Continuous bilateral transcutaneous cervical phrenic nerve stimulation (30 Hz) was applied to nine supine, anesthetized human subjects during transient decreases in airway pressure to levels sufficient to produce flow limitation when unstimulated. Stimulation was applied at two intensities (low and high) and its effects on lung volume and airflow quantified relative to unstimulated conditions. Lung volume increased by 386 ± 269 ml (means ± SD) and 761 ± 556 ml during low and high stimulation, respectively (P < 0.05 for the difference between these values), which was associated with peak inspiratory flow increases of 69 ± 57 and 137 ± 108 ml/s, respectively (P < 0.05 for the difference). Stimulation-induced change in lung volume correlated with change in peak flow (r = 0.65, P < 0.01). Diaphragm descent-related outward displacement of the abdominal wall produced no change in airflow unless accompanied by lung volume change. We conclude that phrenic nerve stimulation-induced diaphragm contraction increases lung volume and reduces airway collapsibility in a dose-dependent manner. The effect appears primarily mediated by changes in lung volume rather than mediastinal traction from diaphragm descent. The study provides a rationale for use of continuous phrenic stimulation to treat obstructive sleep apnea.

Work-related peak flow and asthma symptoms in a damp building

Working in damp conditions is associated with asthma, but few studies have used objective testing to document work-related patterns. To describe the relationship of peak flow measurements to work-related asthma (WRA) symptoms and WRA among occupants in a damp office building. At the beginning of the study, all workers were offered a questionnaire and methacholine challenge testing. Participants were then instructed to perform serial spirometry using handheld spirometers five times per day over a 3 week period. Peak flow data were analysed using OASYS-2 software. We calculated the area between the curves (ABC score) using hours from waking. We considered a score >5.6 L/min/h to be indicative of a work-related pattern. All 24 employees participated in the questionnaire. Seven participants (29%) reported physician-diagnosed asthma with onset after starting work in the building. Almost two-thirds (63%) of participants reported at least one lower respiratory symptom (LRS) occurring one or more times per week in the last 4 weeks. Twenty-two (92%) consented to participate in serial spirometry. Fourteen participants had adequate quality of serial spirometry, five of whom had ABC scores >5.6, ranging from 5.9-23.0. Of these five, two had airways responsiveness, three had current post-hire onset physician-diagnosed asthma and four reported work-related LRS. We found evidence of work-related changes in serial peak flows among some occupants of an office building with a history of dampness. Serial peak flows may be a useful measure to determine WRA in office settings.

Design flood flows with climate change: method and limitations

An extended method is presented for ‘perturbing' design flood flows to account for climate change. Specifically, the method uses climate model output to directly alter parameters in the UK Flood Estimation Handbook rainfall–runoff model. The method is explored using a model of the River Eden catchment in northwest England, which comprises 26 sub-catchment hydrological models, with outflows routed using a hydraulic model. The results show a significant increase in flood flows and water levels by the 2080s, although uncertainties are large. The size of the increases varies depending on the climate change scenario and timing of the event, with the monthly precipitation change factor the single largest determinant of the change in peak flow. The method is reasonably simple to apply and there are benefits of using climate model information, rather than a sensitivity allowance, in terms of geographical interpretation of changes in precipitation and explicit representation of some of the uncertainty related to climate change. However, there are significant limitations to the methodology, in particular the minimal representation of antecedent conditions and more generally due to the ability of climate models to accurately reproduce and simulate extreme precipitation.

Complex land cover change, water and sediment yield in a degraded Andean environment

Rapid land use/-cover change has increasingly transformed the hydrological functioning of tropical Andean ecosystems. The hydrological response to forest cover change strongly depends on the initial state of the ecosystem. Relatively little is known about human-disturbed ecosystems where forest plantations have been established on highly degraded land. In this paper, we analyze the impact of forest change on water and sediment fluxes for a highly degraded Andean catchment. Different pathways of land cover change (1963-2007) are observed in the Jadan catchment, with deforestation taking place in remote uplands and recovery and reforestation in the middle and lower parts where agricultural and bare lands are prevalent. Time series analyses of streamflow and rainfall data (1979/1982-2005/2007) show significant shifts in the distribution of rainfall and flow data. Changes in discharge are not resulting from changes in precipitation, as the direction of change is opposite. The removal of native forest for rangeland or croplands (by -20km 2) is likely to have contributed to the increase in total annual water yield, through an increase in annual baseflow by 25mm. The observed changes in peakflow are important as the 1st percentile highest flow rates were 54% lower, while the 1st percentile rainfall amounts increased by 52%. The observed decrease in peakflow cannot be explained by clearcut of native forest, but is likely to be related to reforestation of degraded lands as well as spontaneous recovery of vegetation on remaining grazing lands. Over the same time period, a major decrease in specific sediment yields and suspended sediment loads was observed. Although deforestation in the upper parts led to increased landslide activity, this change is not reflected in an increased sediment yield. Small upland rivers are often nearly completely blocked by landslide material, thereby reducing their potential to transport sediment. In contrast, the reduction in estimated erosion is likely to be caused by the reduction of the degraded areas in areal extent as well as to the (partial) recovery of the vegetation in these areas. © 2012 Elsevier B.V..

How might climate change affect river flows across the Thames Basin? An area-wide analysis using the UKCP09 Regional Climate Model ensemble

Summary The Thames Basin drains an area of over 10,000 km 2 through London to the North Sea. It encompasses both rural and heavily urbanised areas overlying a spatially-varied and complex geology. Historically, the lower Thames has proved resilient to climate variability, and careful river management in recent years has helped protect the region from flooding. However, recent climate projections for the region indicate that over the next century winter rainfall might increase by 10–15%, potentially leading to higher flows than the Thames can accommodate. This study uses a distributed hydrological model, the Grid-to-Grid (G2G), to assess future changes in peak river flows for a range of catchments across the Thames Basin. The G2G model has used as input an ensemble from the UK Climate Projections (UKCP09) Regional Climate Model (RCM), under the A1B emissions scenario, to analyse changes in flood frequency between two 30-year time-slices (October 1960–September 1990 and October 2069–September 2099). The RCM ensemble uses a perturbed-parameter approach to address uncertainty in climate projections. Results indicate considerable spatial variation in projected changes in peak flows. Towards the downstream end of the fluvial Thames, the average estimated change in modelled 20-year return period flood peaks by the 2080s is 36% with a range of −11% to +68%, which is broadly in line with recent government guidance for the Thames Basin. A key question that arises is whether these estimated changes fall within the range of natural variability and would therefore be indistinguishable from the effects of typical weather patterns in the current climate. Comparison of the modelled changes in flood frequency with an RCM-based estimate of current natural variability shows that, whilst for some rivers (or parts of rivers) there are few changes outside the range of current natural variability, for other rivers there are more changes outside of this range. The latter locations could be considered as sites where further monitoring/modelling may provide early warning of statistically significant changes in observed flows, due to climate change.

Lung Volume Recruitment Slows Pulmonary Function Decline in Duchenne Muscular Dystrophy

McKim DA, Katz SL, Barrowman N, Ni A, LeBlanc C. Lung volume recruitment slows pulmonary function decline in Duchenne muscular dystrophy. ObjectiveTo evaluate the long-term effect on measures of forced vital capacity (FVC) before and after the introduction of regular lung volume recruitment (LVR) maneuvers (breath-stacking) in individuals with Duchenne muscular dystrophy (DMD). DesignRetrospective cohort study of pulmonary function data, including FVC, cough peak flow (CPF), maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP). Data were collected for 33 months prior to and 45 months after LVR introduction. SettingAmbulatory care in a tertiary level regional rehabilitation center in Canada. ParticipantsAll individuals (N=22) with DMD (mean age ± SD, 19.6±2.4y), who were prescribed LVR and reported adherence with therapy. InterventionsIntroduction of regular LVR (breath-stacking); 3 to 5 maximal lung inflations (maximum insufflation capacity [MIC]) using a hand-held resuscitation bag and mouthpiece, twice daily. Main Outcome MeasuresMeasures included the rate of decline of FVC in percent-predicted, before and after the introduction of regular LVR. Changes in maximum pressures (MIP, MEP), MIC, and cough peak flows were also measured. ResultsAt LVR initiation, FVC was 21.8±16.9 percent-predicted, and cough peak flows were <270L/min (144.8±106.9L/min). Annual decline of FVC was 4.7 percent-predicted a year before LVR and 0.5 percent-predicted a year after LVR initiation. The difference, 4.2 percent-predicted a year (95% confidence interval, 3.5–4.9; P<.000), represents an 89% improvement in the annual rate of FVC decline. ConclusionsThe rate of FVC decline in DMD patients improves dramatically with initiation of regular LVR.

Peak flow responses and recession flow characteristics after thinning of Japanese cypress forest in a headwater catchment

We evaluated the effects of forest thinning on peak flow and recession characteristics of storm runoff in headwater catchments at Mie Prefecture, Japan. In catchment M5, 58.3% of stems were removed, whereas catchment M4 remained untreated as a control catchment. Storm precipitation and runoff was monitored from June 2004 to January 2007 for the pre-thinning period (113 events) and from March 2007 to June 2009 for post-thinning (103 events). Based on paired-catchment analysis between M5 and M4, volumes of peak flow did not increase significantly after thinning. Recession constant K increased, while recession time of storm runoff did not differ between pre- and post-thinning periods. Storm hydrograph recession tended to be more gradual (i.e., higher K values) after thinning due to increases in available soil water associated with higher net precipitation and decreased evapotranspiration. The lack of changes in peak flow can be attributed to the minimal soil disturbance during thinning. Our hydrograph analysis in paired catchments indicates that thinning may alter specific internal hydrological pathways, such as subsurface flow and groundwater flow.

Method for testing the accuracy of rainfall–runoff models in predicting peak flow changes due to rainfall changes, in a climate changing context

Summary Catchment hydrological models are widely used in climate change impact studies. The considered climate scenarios often involve increases in rainfall intensities. These increases might go beyond the range of historical events used in model calibration and validation. The hydrological impact results of climate change consequently are under these circumstances highly uncertain. This paper presents a method to test the validity of hydrological models for that type of impact analysis. The method is based on the evaluation of peak flow increases due to different levels of rainfall increases. The method is demonstrated, based upon the results of three conceptual rainfall–runoff models (NAM, PDM, VHM) for three catchments in Belgium. It is shown how the performance of the model in predicting impacts of rainfall increases can be integrated in the calibration process and how this method can increase the reliability of climate change impact results on peak flows. The paper addresses the importance of the relation between the soil moisture content and the overland flow coefficient, as it controls the generation of peak flows in the considered rainfall–runoff models.

실측자료를 이용한 하천의 수위변화 분석 - 강원도를 사례로 -

This study is to analyze the relationship between rainfall and water level using the measured data. During the rainfall event from September 9 to September 12, 2010, the rainfall and water level data were measured from automatic weather systems and automatic water level measurement systems which have been installed throughout Gangwon province. The result showed that the relationship between rainfall and peak flow change was different by basin and tributary. It is expected that this study will help to build a plan for preventing disasters and rainfall-runoff models for the river basins in Gangwon province. 2011년 1월 24일 접수 Received on January 24, 2011 / 2011년 3월 21일 수정 Revised on March 21, 2011 / 2011년 6월 7일 심사완료 Accepted on June 7, 2011 1 강원대학교 지리교육과 Department of Geography Education, Kangwon National University ※ 연락저자 E-Mail : gis119@kangwon.ac.kr Analysis of Peak Flow Changes Using the Measured Data 2

The relative impact of climate change and urban expansion on peak flows: a case study in central Belgium

AbstractAn essential part of hydrological research focuses on hydrological extremes, such as river peak flows and associated floods, because of their large impact on economy, environment, and human life. These extremes can be affected by potential future environmental change, including global climate change and land cover change. In this paper, the relative impact of both climate change and urban expansion on the peak flows and flood extent is investigated for a small‐scale suburban catchment in Belgium. A rainfall‐runoff model was coupled to a hydrodynamic model in order to simulate the present‐day and future river streamflow. The coupled model was calibrated based on a series of measured water depths and, after model validation, fed with different climate change and urban expansion scenarios in order to evaluate the relative impact of both driving factors on the peak flows and flood extent. The three climate change scenarios that were used (dry, wet winter, wet summer) were based on a statistical downscaling of 58 different RCM and GCM scenario runs. The urban expansion scenarios were based on three different urban growth rates (low, medium, high urban expansion) that were set up by means of an extrapolation of the observed trend of urban expansion. The results suggest that possible future climate change is the main source of uncertainty affecting changes in peak flow and flood extent. The urban expansion scenarios show a more consistent trend. The potential damage related to a flood is, however, mainly influenced by land cover changes that occur in the floodplain. Copyright © 2011 John Wiley &amp; Sons, Ltd.