The Fill–Spill Hydrology of Prairie Wetland Complexes during Drought and Deluge

Abstract

Abstract: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.

Field-scale water balance closure in seasonally frozen conditions

“…The hydrological complexity of the landscape is also largely influenced by glacial and post-glacial geomorphological processes, which have imparted a tremendous degree of heterogeneity. Morainal deposits, comprised of a variable mix of soil textures, are often topographically indeterminate and consist of areas which are internally drained and infrequently contribute to stream flow (Zebarth and de Jong, 1989;Shaw et al, 2012).…”

Impacts of climate variability on wetland salinization in the North American prairies

“…Hydrological processes in the region are complex and unusual, characterized by closed basins isolated from any regional drainage network, with drainage via a spill and fill sequence into terminal ponds (Shook and Pomeroy, 2011). Snowmelt runoff from surrounding uplands and precipitation on the wetlands are the dominant hydrological inputs into the wetland systems, together with occasional runoff events due to high-intensity rainfall, whereas snow distribution over the landscape is an important control on the hydrology (Shaw et al, 2012;Spence and Woo, 2003); semi-arid conditions result in minimal shallow groundwater recharge from uplands, while ponds drain to shallow groundwater beneath the depressions (van der Kamp and Hayashi, 2009). …”

The Role of Lake Expansion in Altering the Wetland Landscape of the Prairie Pothole Region, United States

“…Huang et al (2011a) showed a 600 % increase in total surface-water area in the Cottonwood Lake area between 1982 and 2009. Efforts to understand how surface-water expansion can connect features across the landscape have been restricted to wetland-wetland connections (Leibowitz and Vining 2003;Kahara et al 2009), and connections between wetlands and streams (Huang et al 2011b;Shaw et al 2012;Vanderhoof et al 2015). This study extends previous findings Wetlands connected to a lake under both the saturated and inundated thresholds were assumed to be subsumed, while wetlands connected only under the saturated threshold were assumed to have merged with lake (i.e., were not subsumed).…”

“…Intermittent or temporary linear connections (e.g., ephemeral channels, swales, ditches, fill-and-spill events) that connect some waters (Shaw et al 2012) are difficult to detect with Landsat and often are not well documented by NHD, which has been shown to inconsistently map such features (Lang et al 2012;Fritz et al 2013). Although finer spatial resolution imagery may expand the types of connectivity captured, these data sources are often collected on-demand, reducing our ability to capture a wide range of climate conditions.…”