Temperature Time Data Series Indicating Effective Flow Velocities

A fourth way in which temperature data from the Mohawk River were processed is shown in Fig. 4.23. Temperature observations over a whole year are plotted for six wells and for the river. Wells 54 and 59 are seen to follow

Fig. 4.22 Location map of wells near the Mohawk River with annual groundwater temperatures (from Winslow et al., 1965). Using these values, contours of equal annual temperature variation were drawn. The decrease of these contour values indicates water moves from the river into the aquifer, especially through the zone marked A.

Fig. 4.22 Location map of wells near the Mohawk River with annual groundwater temperatures (from Winslow et al., 1965). Using these values, contours of equal annual temperature variation were drawn. The decrease of these contour values indicates water moves from the river into the aquifer, especially through the zone marked A.

the pattern of the river, but with a time shift of about 2 months. Well 21, in contrast, reveals no resemblance to the river at all, and the rest of the wells have intermediate patterns. The degree of similarity to the river is correlated with the distance of the well from the river or, as more precisely stated by the researchers, the degree of similarity reflects the hydraulic distance. By this they mean the combined effect of distance, conductivity, amount of water in transit, and temperature equilibration with the aquifer materials.

The temperature graphs in Fig. 4.23 serve not only to demonstrate recharge, but the time lags in the response of each well to the temperature changes in the river may be divided by the distances from the river to provide effective water velocities. A treatment of this kind for all wells showed a zone of high velocities, marked A in Fig. 4.22.

Fig. 4.23 Temperature records over a whole year in wells near the Mohawk River (following Winslow et al., 1965). Wells 54 and 58 follow the river temperature changes with a time lag. Well 21, most distant from the river, revealed a steady temperature over the year, indicating that river recharge is probably not contributing to this well. The rest of the wells showed intermediate degrees of temperature response to the river temperature variations in proportion to their hydraulic distances.

Fig. 4.23 Temperature records over a whole year in wells near the Mohawk River (following Winslow et al., 1965). Wells 54 and 58 follow the river temperature changes with a time lag. Well 21, most distant from the river, revealed a steady temperature over the year, indicating that river recharge is probably not contributing to this well. The rest of the wells showed intermediate degrees of temperature response to the river temperature variations in proportion to their hydraulic distances.

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