The influence of basin morphology on groundwater outflow

Abstract

Twenty geomorphologic parameters which constitute a well-balanced representation of the area, length, elevation, form, and shape aspects of watersheds as well as the texture of their drainage networks were considered. On the basis of groundwater theory and the results of previous related studies, eight of these parameters were identified as being relevant to the process of groundwater discharge. Values of the selected parameters were obtained for representative watersheds located in a section of the Appalachian Plateaus. The data, which were generated from U.S. Geological Survey topographic maps, were then subjected to a factor analysis to assess the relative importance of the parameters with respect to their influence on groundwater outflow behavior. The analytical results and their interpretation showed that among the parameters that are related to groundwater outflow, total length of perennial streams, average basin slope, and drainage density are the ones that are most closely related to the process. The influences of these parameters on groundwater outflow behavior are independent of each other. Thus in relating groundwater outflow characteristics to basin morphology, only these parameters need be considered and the inclusion of additional parameters does not necessarily yield a better relationship and may result in redundancy. The findings of the study are consistent with existing concepts regarding base flow (or drought flow) and have been confirmed by an independent study that investigated the process based on a more mechanistic approach.

Are streamflow recession characteristics really characteristic?

“…The results of recession analysis are often related directly to physical characteristics such as drainable porosity, hydraulic conductivity, aquifer thickness and other basin-wide hydraulic or geomorphological parameters such as drainage area or stream length (Brutsaert and Nieber, 1977;Zecharias and Brutsaert, 1988b;Parlange et al, 2001;Dewandel et al, 2003). Beyond that, RAMs are often used to estimate recession behavior over different scales (e.g.…”

The hydrological response of baseflow in fractured mountain areas

“…Different authors have estimated average values of recession constants for different geomorphologic regions or geological formations, in some cases establishing quantitative relationships between the recession parameters and the characteristics of the sub-basins (Tóth, 1970;Zecharias and Brutsaert, 1988;Demuth, 1989;Tallaksen, 1989). In these studies, the main indices with influence on the storage-discharge relationship are related to geological features and climate.…”

Estimation of low-flow statistics at ungaged sites on streams in the Lower Hudson River Basin, New York, from data in geographic information systems

“…For 8 of these years, the volume of backwash water in each month was recorded; the number of backwash events in a month typically averaged 2.7 to 4.6 events per day, and the monthly average rate of backwash discharge was typically 0.65 ±0.1 cubic feet per second in the months of July through October when all annual low flows took place (R. Borfitz, assistant chief operator, written commun., 2007). The low-flow indices calculated by Barnes (1986) did not exclude this wastewater discharge.…”

“…Detailed (1:24,000-scale) maps of surficial geology are not available for most localities in New York. Therefore, for this study the distribution of unconsolidated glacial and postglacial sediments overlying bedrock was inferred from county soil surveys, as compiled in the Soil Survey Geographic Database (SSURGO) by the Natural Resources Conservation Service (2007).…”