1. TWRI figures for "Common methods" chapter X1 well lake 97 70 78 80 72 61 70 05001000 75 Figure 1 – A hypothetical lake segmented based on positioning of near-shore water-table wells. Values are hydraulic head and surface-water stage.

2. TWRI figures for "Common methods" chapter X1 well lake 97 70 78 80 72 61 70 05001000 75 Figure 1 – including dimensions. 650 500 430 550 850 600 800 425 200 400 300 275 350 225

3. TWRI figures for "Common methods" chapter X1 A L ground-water flow lines Lake t water- table well shoreline segment Figure 2 –Typical hydraulic conditions in the vicinity of the shoreline of a surface-water body. flow passes beneath lake and is break in slope outside of local flow domain m

4. TWRI figures for "Common methods" chapter X1 hinge line well lake 97 75 70 78 80 72 61 70 0 500 1000 Figure 3 – A flow net generated to indicate flow of water to and from a hypothetical lake. Ground-water flow direction is indicated by flowlines (solid lines) and lines of equal hydraulic head (equipotential lines) are shown with dashed lines. Values shown are hydraulic head and surface-water stage.

5. TWRI figures for "Common methods" chapter X1 hinge line well lake 97 75 70 78 80 72 61 70 0 500 1000 Figure 3 – alternate.

6. TWRI figures for "Common methods" chapter X1 hinge line well lake 97 75 70 78 80 72 61 70 G F E D C B A Figure 4 – Conceptualization of flow based on flow-net analysis and segmented Darcy fluxes. The position of the hinge line changes depending on the method used.

7. TWRI figures for "Common methods" chapter X1 Figure 5 – Hydraulic potentiomanometer (HPM) showing drive well inserted into lakebed and manometer indicating a very small vertical hydraulic-head gradient. (Photo by Don Rosenberry)

8. TWRI figures for "Common methods" chapter X1 Figure 6 – Components of the HPM system. (from Winter et al., 1988)

9. TWRI figures for "Common methods" chapter X1 Figure 7 – Hydraulic potentiomanometer designed to place the manometer tubes connected to the drive probe and to the surface-water body close together to minimize out- of-level errors. (Photo by Jim Lundy)

10. TWRI figures for "Common methods" chapter X1 Figure 8 – HPM potentioprobe with drive hammer, shown driven about 2 m beneath the lakebed. Manometer and hand-crank peristaltic pump are visible in background. (photo by Don Rosenberry)

11. TWRI figures for "Common methods" chapter X1 Figure 9 – Hydraulic potentiomanometer (created by Joe Magner, Minnesota Pollution Control Agency) with manometer connected to drive probe. Note the proximity of the lake and drive-probe tubes to minimize out-of-level errors. Note also the in-line water bottle to keep the vacuum pump dry. (Photo by Don Rosenberry)

12. TWRI figures for "Common methods" chapter X1 Figure 10 – HPM device consisting of a commercially available retractable soil-gas vapor probe connected to threaded pipe with tubing inside the pipe connected to the vapor probe, and a separate tube taped to the outside of the pipe that extends to the lake water surface. (Photo by Don Rosenberry)

13. TWRI figures for "Common methods" chapter X1 Figure 11 – Potentioprobe constructed from a commercially available root feeder with the coiled tubing substituting for a manometer (from Wanty and Winter, 2000).

14. TWRI figures for "Common methods" chapter X1 Figure 12 – MHE PP27 probe used to indicate difference in head (Henry, 2000). (Photo by Mark Henry)

15. TWRI figures for "Common methods" chapter X1 Figure 13 – Half-barrel seepage meter (from Lee and Cherry, 1978). The top panel shows typical installation with bag inserted to a tube inserted through a rubber stopper. The bottom panel shows installation in shallow water with vent tube to allow trapped gas to escape.

16. TWRI figures for "Common methods" chapter X1 Figure 14 – Seepage meter modified for use in large lakes (from Cherkauer and McBride, 1988).

17. TWRI figures for "Common methods" chapter X1 Figure 15 – Seepage meter modified for use in deep water (from Boyle, 1994). 62 cm

18. TWRI figures for "Common methods" chapter X1 Figure 16 – Plastic bag attached to a garden-hose shut-off valve. Bag is filled with a known volume of water and then purged of air. Valve is closed. Bag is threaded onto male threads on seepage meter and valve then is opened to begin seepage measurement. (Photo by Donald Rosenberry)

19. TWRI figures for "Common methods" chapter X1 056113169 226 282339 Seepage flux through standard half-barrel meter, in cm d -1 Figure 17 – Resistance to flow related to tubing diameter and rate of seepage. Seepage flux assumes a 0.25 m 2 -area seepage meter (modified from Fellows and Brezonik, 1980).

20. TWRI figures for "Common methods" chapter X1 Figure 18 – Seepage flux measured at two seepage meters located 1 m apart. Flux values are in m/s (from Shaw and Prepas, 1990). SEEPAGE FLUX, in m/s x 10 -8