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1.
Suburban areas are subject to strong anthropogenic modifications, which can influence hydrological processes. Sewer systems, ditches, sewer overflow devices and retention basins are introduced and large surface areas are sealed off. The knowledge of accurate flow paths and watershed boundaries in these suburban areas is important for storm water management, hydrological modelling and hydrological data analysis. This study proposes a new method for the determination of the drainage network based on time efficient field investigations and integration of sewer system maps into the drainage network for small catchments of up to 10 km2. A new method is also proposed for the delineation of subcatchments and thus the catchment area. The subcatchments are delineated using a combination of an object‐oriented approach in the urban zone and geographical information system–based terrain analysis with flow direction forcing in the rural zone. The method is applied to the Chaudanne catchment, which belongs to the Yzeron river network and is located in the suburban area of Lyon, France. The resulting subcatchment map gives information about subcatchment response and contribution. The method is compared with six other automatic catchment delineation methods based on stream burning, flow direction forcing and calculation of subcatchments for inlet points. None of the automatic methods could correctly represent the catchment area and flow paths observed in the field. The watershed area calculated with these methods differs by as much as 25% from the area computed with the new method. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

2.
The quickflow responses of six subcatchment areas in a small hill country catchment in the Craigieburn Range, South Island, New Zealand, were compared for a range of storm sizes, rainfall intensities and antecedent wetness conditions. Topography and soil characteristics suggested that all subcatchments would receive subsurface stormflow input, but that some would receive larger saturation overland flow inputs than others. Quickflow yields and response ratios were positively correlated with storm size and antecedent wetness conditions in the subcatchment most suited to producing saturation overland flow. In subcatchments more likely to be dominated by subsurface flow, quickflow yields and response ratios were positively correlated with storm size, but were either not correlated, or negatively correlated, with antecedent wetness. Quickflow responses were either not significantly or negatively correlated with rainfall intensity variables. Quickflow from the subcatchment most suited to produce saturation overland flow providing an increasing proportion of total catchment quickflow in larger storms and as antecedent conditions became wetter. Subcatchment responses varied greatly in space and time and there was less pattern to the variation than had been expected. Where topographic and pedologic conditions permit substantial responses to storm rainfall by both saturation overland flow and subsurface stormflow, simple topographic and soil indicators may not be useful guides to the relative importance of runoff mechanisms, or to the identification of runoff-source areas.  相似文献   

3.
Theodore Chao Lim 《水文研究》2016,30(25):4799-4814
Many studies have empirically confirmed the relationship between urbanization and changes to the hydrologic cycle and degraded aquatic habitats. While much of the literature focuses on extent and configuration of impervious area as a causal determinant of degradation, in this article, I do not attribute causes of decreased watershed storage on impervious area a priori. Rather, adapting the concept of variable source area (VSA) and its relationship to incremental storage to the particular conditions of urbanized catchments, I develop a statistically robust linear regression‐based methodology to detect evidence of VSA‐dominant response. Using the physical and meteorological characteristics of the catchments as explanatory variables, I then use logistic regression to statistically analyze significant predictors of the VSA classification. I find that the strongest predictor of VSA‐type response is the percent of undeveloped area in the catchment. Characteristics of developed areas, including total impervious area, percent‐developed open space and the type of drainage infrastructure, do not add to the explanatory power of undeveloped land in predicting VSA‐type response. Within only developed areas, I find that total impervious area and percent‐developed open space both decrease the odds of a catchment exhibiting evidence of VSA‐type response and the effect of developed open space is more similar to that of total impervious area than undeveloped land in predicting VSA response. Different types of stormwater management infrastructure, including combined sewer systems and infiltration, retention and detention infrastructure are not found to have strong statistically significant effects on probability of VSA‐type response. VSA‐type response is also found to be stronger during the growing season than the dormant season. These findings are consistent across a national cross‐section of urbanized watersheds, a higher resolution dataset of Baltimore Metropolitan Area watersheds and a subsample of watersheds confirmed not to be served by (combined sewer systems). Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

4.
Urbanization threatens headwater stream ecosystems globally. Watershed restoration practices, such as infiltration‐based stormwater management, are implemented to mitigate the detrimental effects of urbanization on aquatic ecosystems. However, their effectiveness for restoring hydrologic processes and watershed storage remains poorly understood. Our study used a comparative hydrology approach to quantify the effects of urban watershed restoration on watershed hydrologic function in headwater streams within the Coastal Plain of Maryland, USA. We selected 11 headwater streams that spanned an urbanization–restoration gradient (4 forested, 4 urban‐degraded, and 3 urban‐degraded) to evaluate changes in watershed hydrologic function from both urbanization and watershed restoration. Discrete discharge and continuous, high‐frequency rainfall‐stage monitoring were conducted in each watershed. These datasets were used to develop 6 hydrologic metrics describing changes in watershed storage, flowpath connectivity, or the resultant stream flow regime. The hydrological effects of urbanization were clearly observed in all metrics, but only 1 of the 3 restored watersheds exhibited partially restored hydrologic function. At this site, a larger minimum runoff threshold was observed relative to the urban‐degraded watersheds, suggesting enhanced infiltration of stormwater runoff within the restoration structure. However, baseflow in the stream draining this watershed remained low compared to the forested reference streams, suggesting that enhanced infiltration of stormwater runoff did not recharge subsurface storage zones contributing to stream baseflow. The highly variable responses among the 3 restored watersheds were likely due to the spatial heterogeneity of urban development, including the level of impervious cover and extent of the storm sewer network. This study yielded important knowledge on how restoration strategies, such as infiltration‐based stormwater management, modulated—or failed to modulate—hydrological processes affected by urbanization, which will help improve the design of future urban watershed management strategies. More broadly, we highlighted a multimetric approach that can be used to monitor the restoration of headwater stream ecosystems in disturbed landscapes.  相似文献   

5.
Hydrological budgets and flow pathways have been quantified for a small upland catchment (1.76 km2) in the northeast of Scotland. Water balance calculations for four subcatchments identified spatial variability within the catchment, with an estimated runoff enhancement of up to 25% for the upper western area, compared with the rest of the catchment. Data from spatial hydrochemical sampling, over a range of flow conditions, were used to identify the principal hillslope runoff mechanisms within the catchment. A hydrochemical mixing analysis revealed that runoff emerging from springs in various locations of the hillslope accounted for a significant proportion of flow in the streams, even during storm events. A hydrological model of the catchment was calibrated using the calculated stream flows for four locations, together with results from the mixing analysis for different time points. The calibrated model was used to predict the temporal variability in contributions to stream flow from the hillslope springs and soil water flows. The overall split ranged from 57%:43% spring water:soil water in the upper eastern subcatchment, to 76%:24% in the upper western subcatchment. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

6.
Abstract

In catchments characterized by spatially varying hydrological processes and responses, the optimal parameter values or regions of attraction in parameter space may differ with location-specific characteristics and dominating processes. This paper evaluates the value of semi-distributed calibration parameters for large-scale streamflow simulation using the spatially distributed LISFLOOD model. We employ the Shuffled Complex Evolution Metropolis (SCEM-UA) global optimization algorithm to infer the calibration parameters using daily discharge observations. The resulting posterior parameter distribution reflects the uncertainty about the model parameters and forms the basis for making probabilistic flow predictions. We assess the value of semi-distributing the calibration parameters by comparing three different calibration strategies. In the first calibration strategy uniform values over the entire area of interest are adopted for the unknown parameters, which are calibrated against discharge observations at the downstream outlet of the catchment. In the second calibration strategy the parameters are also uniformly distributed, but they are calibrated against observed discharges at the catchment outlet and at internal stations. In the third strategy a semi-distributed approach is adopted. Starting from upstream, parameters in each subcatchment are calibrated against the observed discharges at the outlet of the subcatchment. In order not to propagate upstream errors in the calibration process, observed discharges at upstream catchment outlets are used as inflow when calibrating downstream subcatchments. As an illustrative example, we demonstrate the methodology for a part of the Morava catchment, covering an area of approximately 10 000 km2. The calibration results reveal that the additional value of the internal discharge stations is limited when applying a lumped parameter approach. Moving from a lumped to a semi-distributed parameter approach: (i) improves the accuracy of the flow predictions, especially in the upstream subcatchments; and (ii) results in a more correct representation of flow prediction uncertainty. The results show the clear need to distribute the calibration parameters, especially in large catchments characterized by spatially varying hydrological processes and responses.  相似文献   

7.
Deleterious effects of urban stormwater are widely recognized. In several countries, regulations have been put into place to improve the conditions of receiving water bodies, but planning and engineering of stormwater control is typically carried out at smaller scales. Quantifying cumulative effectiveness of many stormwater control measures on a watershed scale is critical to understanding how small‐scale practices translate to urban river health. We review 100 empirical and modelling studies of stormwater management effectiveness at the watershed scale in diverse physiographic settings. Effects of networks with stormwater control measures (SCMs) that promote infiltration and harvest have been more intensively studied than have detention‐based SCM networks. Studies of peak flows and flow volumes are common, whereas baseflow, groundwater recharge, and evapotranspiration have received comparatively little attention. Export of nutrients and suspended sediments have been the primary water quality focus in the United States, whereas metals, particularly those associated with sediments, have received greater attention in Europe and Australia. Often, quantifying cumulative effects of stormwater management is complicated by needing to separate its signal from the signal of urbanization itself, innate watershed characteristics that lead to a range of hydrologic and water quality responses, and the varying functions of multiple types of SCMs. Biases in geographic distribution of study areas, and size and impervious surface cover of watersheds studied also limit our understanding of responses. We propose hysteretic trajectories for how watershed function responds to increasing imperviousness and stormwater management. Even where impervious area is treated with SCMs, watershed function may not be restored to its predevelopment condition because of the lack of treatment of all stormwater generated from impervious surfaces; non‐additive effects of individual SCMs; and persistence of urban effects beyond impervious surfaces. In most cases, pollutant load decreases largely result from run‐off reductions rather than lowered solute or particulate concentrations. Understanding interactions between natural and built landscapes, including stormwater management strategies, is critical for successfully managing detrimental impacts of stormwater at the watershed scale.  相似文献   

8.
The impacts of land use intensity, here defined as the degree of imperviousness, on stormwater volumes, runoff rates and their temporal occurrence were studied at three urban catchments in a cold region in southern Finland. The catchments with ‘High’ and ‘Intermediate’ land use intensity, located around the city centre, were characterized by 89% and 62% impervious surfaces, respectively. The ‘Low’ catchment was situated in a residential area of 19% imperviousness. During a 2‐year study period with divergent weather conditions, the generation of stormwater correlated positively with catchment imperviousness: The largest annual stormwater volumes and the highest runoff coefficients and number of stormwater runoff events occurred in the High catchment. Land use intensity also altered the seasonality of stormwater runoff: Most stormwater in the High catchment was generated during the warm period of the year, whereas the largest contribution to annual stormwater generation in the Low catchment took place during the cold period. In the two most urbanized catchments, spring snow melt occurred a few weeks earlier than in the Low catchment. The rate of stormwater runoff in the High and Intermediate catchments was higher in summer than during spring snow melt, and summer runoff rates in these more urbanized catchments were several times higher than in the Low catchment. Our study suggests that the effects of land use intensity on stormwater runoff are season dependent in cold climates and that cold seasons diminish the differences between land use intensities. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

9.
The suitability of the physically based model SHETRAN for simulating sediment generation and delivery with a high degree of spatial (20 m) and temporal (sub‐hourly) resolution was assessed through application of the model to a 167‐km2 catchment leading to an estuary in New Zealand. By subdividing the catchment and conducting calculations on a computer cluster for a 6‐month hydrology initialisation period, it was possible to simulate a large rainfall event and its antecedent conditions in 24 h of computation time. The model was calibrated satisfactorily to catchment outlet flow and sediment flux for a large rainfall event in two subcatchments (~2 km2). Validation for a separate subcatchment was successful for flow (Nash–Sutcliff efficiency of 0.84) with a factor 2.1 over‐prediction for sediment load. Validation for sediment at full catchment scale using parameters from the subcatchment scale was good for flow but poor for sediment, with gross under‐estimation of the dominant stream sources of sediment. After recalibration at catchment scale, validation for a separate event gave good results for flow (Nash–Sutcliff efficiency of 0.93) and sediment load within a factor of two of measurements. An exploratory spatially explicit landslide model was added to SHETRAN, but it was not possible to test this fully because no landslides were observed in the study period. Application to climate change highlighted the non‐linear response to extreme rainfall. However, full exploration of land use and climate change and the evaluation of uncertainty were severely constrained by computational limitations. Subdivision of the catchment with separate stream routing is suggested as a way forward to overcome these limitations. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

10.
The digital elevation model (DEM) has become an essential tool for an increasing array of mountain runoff analyses, particularly the derivation and mapping of stream channel networks. This study examines how well commonly applied DEM‐based channel derivation methods at different spatial resolutions can represent the channel network for a glaciated Rocky Mountain headwater catchment. The specific objectives are to (1) examine how differences in gridded DEM resolution affect spatially distributed values of local slope, specific contributing area, and topographic wetness index derived from both eight and infinite directional flow algorithms, (2) map the actual stream channel network to examine the influence of surface variables on channel initiation, and (3) assess accuracy of DEM‐derived networks compared with the field surveyed network. Results show that for the same contributing area threshold, increasing grid cell size leads to increased channelization of modeled networks. A plot of local slope versus contributing area reveals a negative relationship similar to that of prior studies in un‐glaciated areas but with breaks in slope at contributing areas that are too small to represent thresholds for channelization. Field survey results and evaluation of DEM‐derived channel networks suggest that channel network formation is not clearly related to surface topographic variables at Loch Vale. Digitally derived channel networks do not accurately predict low order channel locations, but approximations of the channel network with drainage density and headward extent of channelization similar to the observed network can be derived with both a 1 m and 10 m DEM using a contributing area threshold of approximately 4x104 m2. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

11.
To mitigate the impacts of impervious surfaces in urban areas, structures such as bioretention systems and permeable pavements have been installed to enhance infiltration in many countries. However, relatively little knowledge is available regarding the performance of such infiltration‐based structures in humid tropical and highly urbanized areas. This study investigates the feasibility of enhancing the infiltration of stormwater in tropical urbanized areas using Singapore as a case study. It first shows that the rainfall depth and intensity are both high, but the time interval between consecutive rainfall event is long in Singapore. It then numerically simulates single‐event local infiltration and finds that the fraction of infiltrated rainfall is actually high. It finally performs catchment‐scale simulations and finds that bioretention systems can enhance infiltration and groundwater recharge particularly during wet periods. However, local mounding of groundwater can be significant and can hinder the performance of those structures. Furthermore, with 5% of catchment area being converted to such structures, the infiltration of the entire catchment is enhanced but still not yet up to the natural level. To increase the overall effectiveness, future studies can look into bioretention systems with underdrain systems. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

12.
In this study, we investigate the surface flow time of rise in response to rainfall and snowmelt events at different spatial scales and the main sources originating channel runoff and spring water in a steep nested headwater catchment (Rio Vauz, Italian Dolomites), characterized by a marked elevation gradient. We monitored precipitation at different elevations and measured water stage/streamflow at the outlet of two rocky subcatchments of the same size, representative of the upper part of the catchment dominated by outcropping bedrock, at the outlet of a soil‐mantled and vegetated subcatchment of similar size but different morphology, and at the outlet of the main catchment. Hydrometric data are coupled with stable isotopes and electrical conductivity sampled from different water sources during five years, and used as tracers in end‐member mixing analysis, application of two component mixing models and analysis of the slope of the dual‐isotope regression line. Results reveal that times of rise are slightly shorter for the two rocky subcatchments, particularly for snowmelt and mixed rainfall/snowmelt events, compared to the soil‐mantled catchment and the entire Rio Vauz Catchment. The highly‐variable tracer signature of the different water sources reflects the geomorphological and geological complexity of the study area. The principal end‐members for channel runoff and spring water are identified in rainfall and snowmelt, which are the dominant water sources in the rocky upper part of the study catchment, and soil water and shallow groundwater, which play a relevant role in originating baseflow and spring water in the soil‐mantled and vegetated lower part of the catchment. Particularly, snowmelt contributes up to 64 ± 8% to spring water in the concave upper parts of the catchment and up to 62 ± 11% to channel runoff in the lower part of the catchment. These results offer new experimental evidences on how Dolomitic catchments capture and store rain water and meltwater, releasing it through a complex network of surface and subsurface flow pathways, and allow for the construction of a preliminary conceptual model on water transmission in snowmelt‐dominated catchments featuring marked elevation gradients.  相似文献   

13.
A topological representation of a rural catchment is proposed here in addition to the generally used topographic drainage network. This is an object‐oriented representation based on the identification of the inlets and outlets for surface water flow on each farmer's field (or plot) and their respective contributing areas and relationships. It represents the catchment as a set of independent plot outlet trees reaching the stream, while a given plot outlet tree represents the pattern of surface flow relationships between individual plots. In the present study, we propose to implement functions related to linear and surface elements of the landscape, such as hedges or road networks, or land use, to obtain what we call a landscape drainage network which delineates the effective contributing area to the stream, thus characterizing its topological structure. Landscape elements modify flow pathways and/or favour water infiltration, thus reducing the area contributing to the surface yield and modifying the structure of the plot outlet trees. This method is applied to a 4·4‐km2 catchment area comprising 43 955 pixels and 312 plots. While the full set of 164 plot outlet trees, with an average of 7 plots per tree, covers 100% of the total surface area of the catchment, the landscape drainage network comprises no more than 37 plot outlet trees with an average of 2 plots per tree, accounting for 52 and 7% of the catchment surface area, when taking account of linear elements and land use, respectively. This topological representation can be easily adapted to changes in land use and land infrastructure, and provides a simple and functional display for intercomparison of catchments and decision support regarding landscape and water management. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

14.
Flow direction and specific catchment area were calculated for different flow‐routing algorithms using TAPES‐G and TauDEM. A fuzzy classification was used along with eight topo–climatic attributes to delineate six landscape classes from a 10‐m USGS DEM. A series of maps and tabular outputs were produced to compare flow‐routing predictions in different parts of the study area in the Santa Monica Mountains of southern California. The matched pair t‐test was used to compare the performance of pairs of specific catchment area grids across six user‐defined fuzzy landscape classes. The results show that (1) the ‘source’ cells predicted with the D∞, DEMON, and FD8 algorithms were confined to hilltops; (2) two single flow‐routing algorithms (Rho8, D8) produced poor results; and (3) the choice of flow‐routing algorithm has potentially important consequences for the calculation of upslope contributing areas, sediment transport capacity, topographic wetness, and several other topographic indices. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

15.
Urbanization strongly changes natural catchment by increasing impervious coverage and by creating a need for efficient drainage systems. Such land cover changes lead to more rapid hydrological response to storms and change distribution of peak and low flows. This study aims to explore and assess how gradual hydrological changes occur during urban development from rural area to a medium‐density residential catchment. The Stormwater Management Model (SWMM) is utilized to simulate a series of scenarios in a same developing urban catchment. Sub‐hourly hydro‐meteorological data in warm season is used to calibrate and validate the model in the fully developed catchment in 2006. The validated model is then applied to other cases in development stage and runoff management scenarios. Based on the simulations and observations, three key problems are solved: (1) how catchment hydrology changes with land cover change, (2) how urban development changes pre‐development flows, and (3) how stormwater management techniques affect catchment hydrology. The results show that the low‐frequency flow rates had remarkably increased from 2004 to 2006 along with the increase of impervious areas. Urbanization in the residential catchment expands the runoff contributing area, accelerates hydrological response, raises peak flows in an order of magnitude of over 10, and more than doubles the total runoff volume. The effects of several LID controls on runoff hydrograph were simulated, and the techniques were able to reduce flows towards the pre‐development levels. However, the partly restored flow regime was still clearly changed in comparison to the pre‐development flow conditions. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

16.
Much debate has occurred in catchment hydrology regarding the connectivity of flow paths from upslope areas to catchment outlets. This study was conducted in two catchments, one with three upper branches, in a loess soil with a fragipan that fosters lateral flow and exhibits an extensive distribution of soil pipe collapse features. The study aimed to determine the connectivity of multiple soil pipe networks as well as determine pipe flow velocities during storm events. Fluorescein dye was injected directly into soil pipes at the upper most pipe collapse feature of four different hillslopes. Breakthrough curves (BTC) were determined by sampling multiple pipe collapse features downslope. The BTCs were used to determine the ‘average’ (centre of mass) and ‘maximum’ (first arrival) flow velocities. This study confirmed that these catchments contain individual continuous soil pipe networks that extend over 190 m and connect the upper most hillslopes areas with the catchment outlet. While the flow paths are continuous, the individual pipe networks consist of alternating reaches of subsurface flow through soil pipes and reaches of surface flow through gullies formed by pipe collapses. In addition, flow can be occurring both through the subsurface soil pipes simultaneous with surface flow generated by artesian flow from the soil pipes. The pipe flow velocities were as high as 0.3 m/s, which was in the range of streamflow velocities. These pipe flow velocities were also in the range of velocities observed in pinhole erosion tests suggesting that these large, mature soil pipes are still actively eroding. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

17.
Mountainous headwaters consist of different landscape units including forests, meadows and wetlands. In these headwaters it is unclear which landscape units contribute what percentage to baseflow. In this study, we analysed spatiotemporal differences in baseflow isotope and hydrochemistry to identify catchment‐scale runoff contribution. Three baseflow snapshot sampling campaigns were performed in the Swiss pre‐alpine headwater catchment of the Zwäckentobel (4.25 km2) and six of its adjacent subcatchments. The spatial and temporal variability of δ2H, Ca, DOC, AT, pH, SO4, Mg and H4SiO4 of streamflow, groundwater and spring water samples was analysed and related to catchment area and wetland percentage using bivariate and multivariate methods. Our study found that in the six subcatchments, with variable arrangements of landscape units, the inter‐ and intra catchment variability of isotopic and hydrochemical compositions was small and generally not significant. Stream samples were distinctly different from shallow groundwater. An upper spring zone located near the water divide above 1,400 m and a larger wetland were identified by their distinct spatial isotopic and hydrochemical composition. The upstream wetland percentage was not correlated to the hydrochemical streamflow composition, suggesting that wetlands were less connected and act as passive features with a negligible contribution to baseflow runoff. The isotopic and hydrochemical composition of baseflow changed slightly from the upper spring zone towards the subcatchment outlets and corresponded to the signature of deep groundwater. Our results confirm the need and benefits of spatially distributed snapshot sampling to derive process understanding of heterogeneous headwaters during baseflow. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

18.
We calibrated an integrated flow–tracer model to simulate spatially distributed isotope time series in stream water in a 7.9‐km2 catchment with an urban area of 13%. The model used flux tracking to estimate the time‐varying age of stream water at the outlet and both urbanized (1.7 km2) and non‐urban (4.5 km2) sub‐catchments over a 2.5‐year period. This included extended wet and dry spells where precipitation equated to >10‐year return periods. Modelling indicated that stream water draining the most urbanized tributary was youngest with a mean transit time (MTT) of 171 days compared with 456 days in the non‐urban tributary. For the larger catchment, the MTT was 280 days. Here, the response of urban contributing areas dominated smaller and more moderate runoff events, but rural contributions dominated during the wettest periods, giving a bi‐modal distribution of water ages. Whilst the approach needs refining for sub‐daily time steps, it provides a basis for projecting the effects of urbanization on stream water transit times and their spatial aggregation. This offers a novel approach for understanding the cumulative impacts of urbanization on stream water quantity and quality, which can contribute to more sustainable management. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

19.
Distributed, infiltration‐based approaches to stormwater management are being implemented to mitigate effects of urban development on water resources. One of the goals of this type of storm water management, sometimes called low impact development or green infrastructure, is to maintain groundwater recharge and stream base flow at predevelopment levels. However, the connection between infiltration‐based stormwater management and groundwater recharge is not straightforward. Water infiltrated through stormwater facilities may be stored in soil moisture, taken up by evapotranspiration or contribute to recharge and eventually base flow. This study focused on a 1.1 km2 suburban, low impact development watershed in Clarksburg, Maryland, USA, that was urbanized and contained 73 infiltration‐based stormwater facilities. Continuous water table measurements were used to quantify the movement of infiltrated stormwater. Time series analyses were performed on hydrographs of 7 wells, and the episodic master recession method was used. Persistence in water levels, as measured by autocorrelation function, was found to be positively related to depth to water. Storm properties (precipitation rate and duration) and well location (proximity to the nearest stream) were significant in driving episodic recharge to precipitation ratios. The well that had the highest recharge to precipitation ratios and water table rises of up to 1.5 m in response to storm events was located furthest from the stream and down gradient of stormwater infiltration locations. This work may be considered in evaluating the effects of planned watershed‐scale infiltration‐based stormwater management on groundwater flow systems.  相似文献   

20.
Some relatively straightforward modifications to the Distributed Hydrology–Soil–Vegetation Model (DHSVM) are described that allow it to represent urban hydrological processes. In the modified model, precipitation that falls on impervious surfaces becomes surface runoff, and a spatially varying (depending on land cover) fraction of surface runoff is connected directly to the stream channel, with the remainder stored and slowly released to represent the effects of stormwater detention. The model was evaluated through application to Springbrook Creek watershed in a partially urbanized area of King County, Washington. With calibration, the modified DHSVM simulates hourly streamflow from these urbanized catchments quite well. It is also shown how the revised model can be used to study the effects of continuing urbanization in the much larger Puget Sound basin. Model simulations confirm many previous studies in showing that urbanization increases peak flows and their frequency, and decreases peak flow lag times. The results show that the urbanization parameterizations for DHSVM facilitate use of the model for prediction and/or reconstruction of a range of historic and future changes in land cover that will accompany urbanization as well as other forms of vegetation change. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

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