664 Transactions. — Geology. 



2. Many fluctuations, apparently erratic, are no doubt due 

 to irregular causes of which I can give no account — such as 

 the stopping of rams ; less pumping by windmills on calm 

 days; rainfall outside Christchurch ; watering the streets; 

 opening of new wells, &c. 



3. Certain fluctuations are sufficiently regular to show 

 cause and effect : they are — (a) Eise after rain, unless the 

 ground is very dry ; {b) rise at night, owing to less water being 

 used. 



4. The rise at night in each well is about equal ; conse- 

 quently, as the second stratum fluctuates more rapidly than 

 the first stratum, the supply to the first stratum must be 

 larger than that to the second. 



5. This rise without rain appears to be the main source of 

 supply. It must be due either to water running in from the 

 bed of the Eiver Waimakariri, or to some still lower water- 

 bearing stratum leaking into the upper ones. 



6. The height of the water in the wells is not affected by 

 the height of the river. It is therefore improbable that the 

 supply is from a leak in the river-bed. 



7. The regular inflow — independent of rain — is, with each 

 stratum, greater than the present outflow by night, but smaller 

 than the outflow by day. 



Lastly, we come to the question of the annual rate of 

 lowering of the water. Of course, one year's observations are 

 not enough to settle this point accurately, but they are better 

 than nothing. The shallow well stands about Ifin. and the 

 deep well about 2fin. below the level of last year. The annual 

 rainfall was 22-21in., which is 2in. or Sin. below the average; 

 but I do not think that this will account altogether for the 

 fall. No doubt heavy rain would make the wells go up again 

 to last year's level, but they would go down again in two or 

 three weeks. 



The shallow wells are estimated by Mr. T. Danks to have 

 fallen between 6ft. and 7ft. during the last thirty years, which 

 gives an average annual fall of between 2-Jin. and 2fin. Mr. 

 H. Oakley has estimated that they have fallen 3ft. in twenty 

 years, which is rather more than Ifin. a year. Mr. Oakley 

 also thinks that the deep wells have fallen 3ft. in six or seven 

 years, which is an average of 5iin. a year. This rate of lower- 

 ing requires further investigation ; but no doubt it is serious, 

 and increasing year by year. 



