Analytical and Numerical Models to Explain Steady Rates of Spring Flow

Abstract

Flow from some springs in former glacial lakebeds of the Upper Midwest is extremely steady throughout the year and does not increase significantly after precipitation events or seasonal recharge. Analytical and simplified numerical models of spring systems were used to determine whether preferential ground water flow through high-permeability features in shallow sandstone aquifers could produce typical values of spring discharge and the unusually steady rates of spring flow. The analytical model is based on a one-dimensional solution for periodic ground water flow. Solutions to this model suggest that it is unlikely that a periodic forcing due to seasonal variations in areal recharge would propagate to springs in a setting where high-permeability features exist. The analytical model shows that the effective length of the aquifer, or the length of flowpaths to a spring, and the total transmissivity of the aquifer have the greatest potential to impact the nature of spring flow in this setting. The numerical models show that high-permeability features can influence the magnitude of spring flow and the results demonstrate that the lengths of ground water flowpaths increase when high-permeability features are explicitly modeled, thus decreasing the likelihood for temporal variations in spring flow.

The hydrogeological and cultural background for two sacred springs, Bø, Telemark County, Norway

“…Then, the spring discharge will be steadier due to a higher storage coefficient and a long flow length. Analytical and numerical modeling results show that discharge steadiness for a spring from a phreatic aquifer of coarse material increases with length of the flow (Swanson and Bahr, 2004).…”

Evidence for preferential flow through sandstone aquifers in Southern Wisconsin

“…7). Generic analytical and simplified, transient numerical models based on this conceptual model adequately explain the transient flow characteristics that are typical of spring flow in this area (Swanson and Bahr, 2004). In this study, a site-specific, steady-state numerical model was developed to further test whether features that are hydraulically continuous across tens of kilometers can also explain the localization and spatial distribution of spring flow in the landscape.…”

The morphology and hydrology of small spring-dominated channels

“…Recent work comparing the hydrology and geomorphology of spring-dominated channels to runoff-dominated channels in areas of Oregon, Idaho, and Montana (Stamm and Whiting, 1994;Whiting and Stamm, 1995;Whiting and Moog, 2001) has shown significant differences in morphology. The hydrograph of spring-dominated systems shows comparatively little change throughout the year (Manga, 1996;Swanson and Bahr, 2004), resulting in prevalent bankfull or near bankfull conditions. In comparison, runoff-dominated channels have relatively little base flow and exhibit a much more variable character dependent on the magnitude of local precipitation events (Manga, 1996).…”