42. 



DR. KOHMAN: How was the water table related to the 

 Columbia River? 



DR. L. F. CURTISS: Is it different from the level of the 

 river? 



MR. PIPER: If you wish to defer that for a moment, I would 

 like to come to it later. I -would like to caution against any interpre- 

 tation that we can show conclusively in wells of this sort what happens 

 to the fluid: it passes down largely in an unsaturated state and a test 

 hole may penetrate the zone of .percolation and not collect a single 

 drop of fluid. Similarly with well sampling of the water at the ground 

 water table: contaminated water may be caught or it may go by un- 

 detected. 



I doubt that the present practice of discharging low-level wastes 

 could be continued over the centuries, and wouldn't for a moment 

 consider adopting this practice in a populous area. I feel the problem 

 of waste-product disposal is far from solved. 



There is another aspect to disposal in cribs at Hanford. Most 

 of the waste cribs are roughly in the center of the area bounded by 

 a large bend of the Columbia River. The diagonal across this area 

 measures about 40 miles. The water table does not slope uniformly 

 across the area. A couple of intermittent streams discharge into the 

 area from the hills to the west, and have formed a natural ground 

 water ridge. The ridge merges with a rather gentle ground-water 

 slope and induces a general radial movement of ground water in the 

 central area, toward the river. This natural pattern has been com- 

 plicated by disposal of cooling water in the plant area, which has 

 built a couple of rude ground-water mounds, possibly several tens of 

 feet higher than the natural water table. These two mounds act es- 

 sentially as dams to the movement of water and, for the moment, they 

 hold back the water that is beneath the cribbed area. We can't say 

 definitely what the condition may be 25 years from now. 



DR. CURTISS: What is the nature of the ground? Can you give 

 us a cross-section or rough sketch. 



MR. PIPER: On the west side of the area there is a ridge of 

 basalt, 1500 or 2000 feet high. From its base, a rudely terraced 

 plain descends to the river. The water table is relatively steep at 

 the west side, then flattens beneath the central plain. 



