150 CONSERVATION OF GROUND WATER 



along the streams, coal culm and sludge on the river bottom, 

 doubtless are largely responsible for this deterioration. 73 



Contaminated stream water is not necessarily an indication 

 that all the water in a watercourse is unsuitable for use. As an 

 example, the Red River in Louisiana carries water too hard 

 for most purposes, and the ground water in the alluvium is of 

 similar composition. But the ground water has a more uni- 

 form temperature than the surface water, which makes it suita- 

 ble for use in cooling or air conditioning. Use of this water 

 has been recommended at Shreveport, where concentrated 

 draft on another ground-water reservoir has caused a progres- 

 sive decline of water levels, with the result that many wells 

 have been abandoned. 



Data from wells adjacent to the highly polluted Ohio River 

 indicate that coliform bacteria are not transmitted into them 

 from the river. Whether there is wholesale destruction of 

 pathogenic organisms in the silt and sludge of the river bottom, 

 or during the nitration through permeable materials, is not 

 known. Scientific data are still far too meaner to define the 

 limits of safety from pathogenic organisms where a well in- 

 duces infiltration from a polluted stream (see page 202). 



WHERE THE SURFACE WATER IS USED DOWNSTREAM 



The water in most western streams is not a surplus that will 

 flow unused to the ocean, but is on its way to some downstream 

 user. Pumpage from wells that induces infiltration from such 

 a stream becomes an infringement on the previously estab- 

 lished rights of the downstream users. However, many of these 

 watercourses discharge large quantities of water to the atmos- 

 phere by evaporation or transpiration that is of no benefit to 

 mankind. Salvaging this wasted water requires methods of 

 ground-water development that will divert water only from 

 the area of consumptive waste, without depleting the quan- 

 tity of water available for downstream uses. 



In some western valleys ground water has been developed 



73 Graham, J. B., Ground-water Problems in the Philadelphia Area, Econ. 

 Ceol., vol. 45, pp. 210-221, 1950. 



