Browsing by Subject "hydrology"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Impacts of Development Pattern on Urban Groundwater Flow Regime(American Geophysical Unioon, 2018) Barnes, Michael L..; Welty, Claire; Miller, Andrew J.We compare the effects of urban development type and spatial pattern on the hydrology of six small headwater catchments near Baltimore, Maryland utilizing a three-dimensional coupled groundwater-surface water-land atmosphere model (ParFlow.CLM). The catchments range in size from 0.2 - 2 sq km, across a spectrum of older heavily urbanized development to less developed exurban residential areas. The topography and land cover of each model domain is defined using high-resolution LiDAR topography and orthoimagery. Simulations were conducted at an hourly time-step for calendar years 2012-2015 using a 10-m terrain-following horizontal grid with variable dz (0.1 m to 8 m). Differences in development type and pattern across catchments give rise to complex spatial and temporal trends in the water budget. Catchments with the lowest amounts of impervious cover show the greatest variability in total storage response to climatic variation, whereas those with the greatest amount of impervious cover show less variability in response of subsurface storage to annual and seasonal variability in precipitation input. The storage response among catchments tends to be pronounced during prolonged dry and wet periods, with the variability in response being less pronounced over short-term events. A negative correlation is observed across catchments between impervious cover and net subsurface storage variability. Temporal variability in subsurface storage is most responsive to development pattern in near-surface layers, but transitions to topographic control at depth. Spatially, the development footprint controls where recharge and evapotranspiration occur in the unsaturated zone. Infiltration in pervious areas flows laterally beneath impervious surfaces.Item River‐valley morphology, basin size, and flow‐event magnitude interact to produce wide variation in flooding dynamics(John Wiley & Sons, 2019-01-03) Appledorn, Molly Van; Baker, Matthew; Miller, Andrew J.Inundation dynamics are a key driver of ecosystem form and function in river‐valley bottoms. Inundation itself is an outcome of multi‐scalar interactions and can vary strongly within and among river reaches. As a result, establishing to what degree and how inundation dynamics vary spatially both within and among river reaches can be challenging. The objective of this study was to understand how river‐valley morphology, basin size, and flow‐event magnitude interact to affect inundation dynamics in river‐valley bottoms. We used 2D hydraulic models to simulate inundation in four river reaches from Maryland's Piedmont physiographic province, and qualitatively and quantitatively summarized within‐ and among‐reach patterns of inundation extent, duration, depth, shear stress, and wetting frequencies. On average, reaches from confined valley settings experienced less extensive flooding, shorter durations and shallower depths, stronger gradients of maximum shear stress, and relatively infrequent wetting compared to reaches from unconfined settings. These patterns were generally consistent across flow‐event magnitudes. Patterns of within‐reach flooding across event magnitudes revealed complex interactions between hydrology and surface topography. We concluded that valley morphology had a greater impact on flooding patterns than basin size: Inundation patterns were more consistent across reaches of similar morphology than similar basin size, but absolute values of inundation characteristics varied between large and small basins. Our results showed that the manifestation of out‐of‐bank flows in valley floors can vary widely depending on geomorphic context, even within a single physiographic province, which suggests that hydrologic and hydraulic conditions experienced on the valley floor may not be well represented by existing hydrologic metrics derived from discharge data alone. We thus support the notion that 2D hydraulic models can be useful hydrometric tools for cross‐scale investigations of floodplain ecosystems.Item Using Detailed Terrain Analysis to Understand Spatiotemporal Patterns of Floodplain Hydraulics and Sediment Deposition(2018-01-01) Clifton, Zachary John; Baker, Matthew E; Geography and Environmental Systems; Geography and Environmental SystemsSediment transport in rivers plays multiple key roles within every watershed. Fine sediments transported by rivers carry with them vital nutrients that are essential to riverine and estuarine life, when not in excess. Floodplain storage of these same fine sediments is of interest to parties attempting to mitigate downstream sediment and nutrient pollution. However, historic methodological and technological limitations have limited fine-scale studies of floodplain storage. This exploratory study, utilizing modern multi-temporal high-resolution topography and advanced geospatial analysis tools, sought to overcome these limitations and comprehensively assess floodplain sediment dynamics and the conditions governing them. Our findings suggest that in addition to geometric measures, flow conditions across a floodplain during the falling limb are strong predictors of floodplain-scale sedimentology. Further results suggest modern high-resolution topography is capable of adequately modeling fine-scale sediment dynamics from single storms, accurately characterizing low-relief landforms, and providing detailed terrains for hydraulic models.