294 THE IRRIGATION AGE. 



be equal to 7,108,173 gallons per acre, or a rainfall of 210 inches per 

 year and 262 inches to mature the crop. 



The report proceeds to give examples, and begins with the Ha- 

 waian Commercial Company's plantation at Spreckelsville, island of 

 Maui, of which it says: 



The record for the calender year 1888 shows that there was delivered to the 

 plantation the following quantity of water: 



Cubic feet. 



From the Haiku ditch 1,175,000,000 



From the Waihee ditch 919,000,000 



2,094,000,000 



Or 15,700,000,000 gallons. The rainfall during this period was 19.08 inches. 



With this water there were irrigated 2,000 acres of ''plant cane" and 600 acres 

 of "ratoons" (volunteer second crop). In addition. 400 acres of seed cane were irri- 

 gated once a month, consuming a quantity roughly estimated at 70,000.000 cubic 

 feet. The remaining 2,024.000.000 cubic feet would be equivalent t<> a constant 

 ' average flow through the year of 64.18 cubic feet per second, which, divided into 

 2,600 acres, would appear to give an average duty of 40.5 acres per cubic foot per 

 second, and to indicate that the mean depth applied was nearly 18 feet in the aggre- 

 gate (22 feet, or 264 inches, for the crop period of fifteen months) 



The report states that the explanation for "this seemingly low 

 duty" may be found in the fact that the water was also used for cattle, 

 domestic, and other purposes. 



Mr. Hugh Morrison, general manager of the plantation at Spreck- 

 elsville, states, as an epitome of his experience, that 11,000 cubic feet 

 per acre applied every seven days will produce the very best results 

 in growing sugar cane. Covering'the period of fifteen months already 

 stated, that amount was equal to 5,348,200 gallons per acre, or a rain- 

 fall of 197 .inches, which with the 19.08 inches of actual rainfall makes 

 a total of 216.08 inches to produce the crop. The report continues: 



Mr. Morrison further adds that it is almost impossible to put on too much water 

 of course within reasonable limits), and that the more water is applied, without go- 

 ing to extremes, the greater the yield He has obtained a yield as high as 10 tons 

 of sugar per acre in localities sheltered from the wind. The average yield *of 1888 

 on 2,000 acres of plant cane was 5| tons of sugar per acre; the raroon crop averaged 

 3 tons per acre. 



On the Wailuku plantation, island of Maui, where the water supply is very 

 abundant and in excess of the needs of the plantation, the consumption is equal to a 

 duty of about 50 acres per cubic foot per second on plant cane and 60 acres on ra- 

 toons. 



On the Hamakuapoko plantation, Maui, where the average annual rainfall is re- 

 ported as 36.2 inches, the amount applied is stated by the superintendent. Mr. 

 James Cowan, to be 10,890 cubic feet per acre to each watering. The intervals be- 

 tween waterings are seven days, and consequently the duty of water in continuous 

 flow is 55.5 acres per cubic foot per second. 



This amount is equal to a depth of 195 inches, which, with the 

 natural fall of 35.2 inches of rain, is equivalent to a total rainfall of 

 230.2 inches to mature the crop, or 184.2 inches per annum. Contin- 

 uing, the report says: 



