Jeffrey D. Niemann

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Many stormwater modeling problems consider watersheds comprised of complex flow networks including surfaces, streets, pipes, and channels. Ideally, hydrologic methods would be used to model the accumulation of runoff on surfaces while hydraulic methods would be used to explicitly model the flow in each street, pipe, and channel. In many practical(More)
Playfair's law (J. Playfair, illustrations of the Huttonian Theory of the Earth, 1802) requires any two tributaries in a river network to lower at the same rate near their junction. Although this law holds exactly at the junction, it is unclear how well it holds in the vicinity of the junction. This issue has practical importance because Playfair's law has(More)
Spatial patterns of soil moisture cannot be adequately characterized by direct measurement for most practical applications, so interpolation between observations is required. Interpolation of soil moisture is complicated because multiple hydrologic processes can affect soil moisture and these processes can introduce distinct modes of variation into the soil(More)
The spatial structure of soil moisture is important in many catchment-scale hydrologic applications including flood forecasting and watershed and land management. Unfortunately, estimating these patterns at suitable resolutions (e.g., patterns with 10 – 30 m grid cells) is difficult. In many instances, coarse-resolution patterns obtained from remote sensing(More)
The Arkansas River, one of four major rivers that begin in Colorado, has the largest drainage basin in the state and serves as a vital source of water. At peak flows, the Arkansas River swells by 70% through Chaffee County, in the heart of the Rockies, and only increases by 20% before exiting the mountains onto the high plains near Pueblo. The production of(More)
Soil moisture is an important hydrologic state variable, affecting both the partitioning of energy into sensible and latent heat fluxes and the partitioning of precipitation into infiltration and runoff. In addition, the spatial patterns of soil moisture within a catchment also influence the catchment's hydrologic behavior including the timing and quantity(More)
Soil moisture acts as a key state variable in the interaction between the atmosphere and land surface, strongly influencing radiation and precipitation partitioning and thus many components of the hydrologic cycle. However, measuring soil moisture patterns with adequate spatial resolutions over useful spatial extents remains a significant challenge due to(More)
The Lower Arkansas River Valley in Southeastern Colorado is an important agricultural region. More than a century of intensive irrigation has raised the water table of the region causing several agroecological problems including water logging, soil salinization, and leaching of selenium into waterways. These issues could be addressed, in part, through(More)
Soil moisture is a critical variable for numerous hydrologic and ecological processes, but direct measurement of catchment-scale soil moisture patterns is time consuming and expensive. Many efforts have been made to estimate soil moisture patterns based on readily available information such as topography, which is known to affect soil moisture patterns(More)
Soil moisture is a key state variable in land surface-atmospheric interactions, strongly influencing radiation and precipitation partitioning and thus many components of the hydrologic cycle. However, physical and economic constraints make measurement of soil moisture patterns with adequate spatial resolutions and spatial extents impractical. In particular,(More)