94 A GEOLOGICAL SUK^'EY OF LASDS 



The head of the waters in this basin will no dobt be found to 

 vary at different points to some extent. Such variations are not 

 unknown in regions with a more regular geological structure than 

 this basin. The deepest water can be expected to exhibit the least 

 variations in this respect. A well which was recently made at a 

 point about three miles west of the "Cross S" ranch by Mr. Archi- 

 bald gives us an approximate measure of the height of the head 

 of this lowest water. Four measurements by the aneroid baro- 

 meter make the elevation of the curb of this well 54 feet above 

 low water of the Nueces rirer at the ranch. The elevation of the 

 Nueces low water at this point is estimated at 667 feet above the 

 sea level. The curb of the well is therefore about 721 feet above 

 the sea. The water is said to rise ten feet above the curb, and its 

 head must be near 730 feet. At present the well is tapped through 

 a ditch fifteen feet below the curb. 



All the lowlands belonging to the Company in the northwest 

 part of Webb county are below this level and there is good reason 

 for believing that flowing wells may be made by sinking wells into 

 the lowest tertiary sands under these lands. An estimate of the 

 thickness of the tertiary beds on the Eio Grande on these lands 

 indicates not less than 1,000 feet and not more than 1,500. This 

 thickness would have to be penetrated in order to make a fair 

 test. 



Waste of Flowing Water. 



The unrestricted waste of water in the Carizzo Springs' basin 

 will soon be a matter of concern to land owners north and west 

 of the wells as well as to owners of land irrigable by this water. 

 As has been indicated already, the intake area of this water is on 

 the sandy lands between Chacon creek and Turkey creek south of 

 the Anacacho moimtains, extending about as far south as to 

 Wilderness lake. AYith such a limited intake area a too liberal 

 draught on the supply will certainly reduce the head, and not 

 only will the wells with the lowest pressure cease flowing, but the 

 underground water level in the intake area will sink and with 

 this must follow a general scarcity of water in shallow wells and 

 in tanks dependent on surface supply in this region. For with a 

 lowering of the level of the ground moisture the water which 

 supplies the vegetation, the tanks and natural water holes, will 

 be less, and the general seepage downward wUl be more rapid. 



