6S 



Avater is found in the Miocene o£ the immediate neighbourhood, 

 :and in Section 3076, Hundred of Barossa, where water is found 

 in the fundamental rocks, the waterline is considerably hi^^jher 

 than that in the Gawler drift sands. Taking into consideration 

 the limited depth of clayey deposits overlying the drift sands 

 in the beds of the jN'ortli and Soutli Para Kivers, it is therefore 

 evident that the water supply obtained in the Government and 

 private wells throughout Gawler is chiefly derived from infil- 

 tration of river waters as they pass over the thin superficial 

 stratum of pervious deposit at or near the junction of the Drift 

 with the old rocks. In support of this opinion I have to state 

 that the South Para ceases to flow for five months in twelve 

 over the Drift within a few yards of the Government well, 

 which is only 35 feet in depth "from the surface to the water- 

 line ; and as the bed of the river is 15 feet below the level of 

 the mouth of the well, consequently the river bed is but 20 

 feet above the water-line in the well. The stream, thus 

 situated, and flowing — especially during high flood — a distance 

 of not less than 15 chains over so perA^ous a material, as shown 

 by the strata exposed in the well, must ])enetrate and sur- 

 charge the underlying sands and gravels to the fullest extent. 

 Whilst considering this seemingly unlimited water supply, we 

 must not overlook the fact that' the beds in which it is stored, 

 ^t an elevation of 132 feet above sea level, constitute an 

 integral part of a formation extending far below the present 

 shore line ; it is, therefore, perfectly evident that a barrier of 

 impervious material, sufiicient to oppose the further downflow 

 ■of the water absorbed by the Gawler sandbeds, exists at no great 

 distance to the west, otherwise these beds would, like their 

 prototypes east of Smithfield and in Section 3205, Muuno 

 Para, be non-productive of water, showing also that the 

 well from which the Gawler A\''aterworks is supplied merely 

 taps this subterranean lake, and derives its supph^ chiefly 

 from the flood-waters of the South Para. It, therefore, becomes 

 a critical point to consider whether its contents during the dry 

 .season — especially a prolonged one — will be sufiicient to meet 

 the requirements for which the works were originally executed. 



Previous to the Government undertaking, the Drift yielded, 

 for all purposes, a moderate suppl}^ of subterranean water 

 from wells throughout the town and suburbs. The supply of 

 these being derived from the same source, it is highly probable 

 that the Government well will partially drain those during 

 summer droughts, and the inhabitants and factories, especially 

 the latter, will become dependent upon the waterworks for a 

 supply during those periods. 



Miocene. — About Gawler and "Western Parossa, as in Munuo 

 Para, the Miocene beds, though good rain collectors and of 



