ALBERT

Description: The Journal of Organic Chemistry DOI: 10.1021/acs.joc.5b02456

Description: The fill-spill of surface depressions (wetlands) results in intermittent surface water connectivity between wetlands in the prairie wetland region of North America. Dynamic connectivity between wetlands results in dynamic contributing areas for runoff. However, the effect of fill-spill and the resultant variable or dynamic basin contributing area has largely been disregarded in the hydrological community. Long-term field observations recorded at the St. Denis National Wildlife Area, Saskatchewan, allow fill-spill in the basin to be identified and quantified. Along with historical water-level observations dating back to 1968, recent data collected for the basin include snow surveys, surface water survey and production of a light detection and ranging-derived digital elevation model. Data collection for the basin includes both wet and dry antecedent basin conditions during spring runoff events. A surface water survey at St. Denis in 2006 reveals a disconnected channel network during the spring freshet runoff event. Rather than 100% of the basin contributing runoff to the outlet, which most hydrological models assume, only approximately 39% of the basin contributes to the outlet. Anthropogenic features, such as culverts and roads, were found to influence the extent and spatial distribution of contributing areas in the basin. Historical pond depth records illustrate the effect of antecedent basin conditions on fill-spill and basin contributing area. A large pond at the outlet of the St. Denis basin, which only receives local runoff during dry years when upstream surface storage has not been satisfied, has pond runoff volumes that increase by a factor of 20 or more during wet years when upstream antecedent basin surface storage is satisfied and basin-wide runoff contributes to the pond. © 2011 John Wiley & Sons, Ltd.

Description: The unique topography of the pothole region of the North American prairies creates challenges for properly determining basin contributing area. Numerous depressions or potholes within the landscape impound runoff. However, potholes can 'fill-spill' resulting in surface water connections between the potholes. Surface water connectivity between potholes ultimately influences basin contributing area. Currently, automated methods, such as landscape analysis tools, treat depressions in the landscape as artifacts and simply fill the depressions to delineate a drainage basin. Using this method to calculate contributing area assumes that all surface storage has been satisfied (threshold) and the drainage basin will contribute 100% of its area for all runoff events. However, most runoff events in the prairie pothole region are pre-threshold events that contribute only a portion of surface runoff to the outlet. These pre-threshold events have surface storage that varies because of antecedent water levels and have a variable or dynamic potential to store further runoff in the basin. Government agencies have developed methodologies for determining pre-threshold contributing areas, but these methodologies do not incorporate current technologies and, as a result, have limitations. We propose an automated method for determining contributing area that incorporates the fill-spill of prairie potholes. The algorithm, which uses the D-8 drainage direction method, automates a methodology for identifying and quantifying runoff contributing area. Any algorithm that determines pre-threshold contributing area, must allow the DEM to be filled in an incremental manner. This will simulate increasing pond levels, and the resulting decrease in available storage in the basin, in response to runoff events. The SPILL algorithm is an iterative solution that increases the magnitude of input runoff events and records the decreasing change in available surface storage and the increase in contributing area until the storage threshold is reached and the contributing area reaches 100%. Through application of the algorithm on prairie pothole region basins, we test proposed conceptual curves that describe a hypothesized non-linear relationship between decreasing potential storage in the landscape and contributing area. Results indicate that the proposed conceptual curves represent the relationship between potential surface storage and contributing area in the test basins very well. © 2012 John Wiley & Sons, Ltd.

Description: Physiographic data are often used to parameterize hydrological models and, in the past, physiographic parameters have often been derived manually. However, this can be a lengthy and unreliable process, particularly for application to a gridded hydrological or atmospheric model applied to large or continental-scale basins. An important attribute of gridded models is drainage direction. Current methods that determine drainage directions for large or continental-scale basins, by general circulation models (GCMs), route flow using lowest neighbour algorithms. These methods, however, do not reflect the hydrology of the basin subunit. This paper proposes a method of parameterizing hydrological models with physiographic data using the ArcInfo macro language to create an interface between the Topographic Parameterization (TOPAZ) software and the WATFLOOD hydrological model. The interface uses output raster data created by TOPAZ (i.e. drainage identification) to supply physiographic parameters required by WATFLOOD. The interface (WATPAZ) is an expert system based on a manual method of deriving parameters for the WATFLOOD distributed model. The WATPAZ interface uses grouped response units to subdivide the watershed. This allows large drainage basins to be subdivided at a scale that allows computational efficiency while preserving the hydrological variability of the watershed. To test whether the WATPAZ method improves the current GCM methodology for determining drainage directions, WATPAZ is applied on a local basin (Wolf Creek) a regional-scale basin, (Athabasca) and a continental-scale basin (Mackenzie). An examination of flow directions derived from this new method with current GCM methods is carried out. The results indicate that a substantial improvement is made to flow routing within the basin using the channel network to determine drainage directions for each segment. Copyright © 2005 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.