Water Level Regimes in a Swamp

Abstract

<p>This research studies the spatial and temporal variations of the watertable of Beverly Swamp (Southern Ontario), within the context of the hydrology of the area. Fieldwork was conducted from April to November, 1977, and it concentrated on the monitoring of water levels at selected sites in the swamp.</p> <p>Results indicate that there is a strong interaction between streamflow and subsurface flow, which led to a classification of swamp water level regimes. In general, streams entering the swamp tend to impose their regime on the surrounding aquifer which thus experiences a "periodically effluent" regime, with periods of marked influent flow. The flow of the streams starting at the swamp, instead, depends on the watertable of the surrounding aquifer, which experiences a "predominantly effluent" regime.</p> <p>The relationship between swamp water levels and outflow is analyzed in detail. At a seasonal scale, this relationship is non-linear, and at a reduced time scale it shows a series of hysteresis loops caused by two factors. The first is related to a translation time lag, and the second to different discharges resulting from a given watertable level.</p> <p>Stream level, evaporation and rainfall data are then used in a numerical model which synthesizes the water level hydrographs at several sites in the swamp.</p> <p>Finally, runoff regulation ability of the swamp is examined, and it is concluded that it is of small magnitude, noticeably only in small-volume, flashy inputs to the swamp.</p>