1903 



FORESTRY AND IRRIGATION 



125 



facts should obtain together is proof 

 that such waters used with judgment 

 and good drainage are not deleterious. 

 It may be said, however, that the Ewa 

 supply, when not overdrawn, remains 

 comparatively sweet. The lifts on this 

 plantation do not exceed 250 feet, and 

 the cost of the pumping system for main- 

 tenance during 1901 was $35. 72 per acre. 



The pumping plants of the Hawaiian 

 Commercial and Sugar Company on the 

 Island of Maui show as great a variety 

 of types as can be found on the islands. 

 The engines used vary from the old-style 

 poppet valve to the compound condens- 

 ing Corliss and triple-expansion types. 

 The pumps used are the centrifugal, 

 direct-acting plunger, automatic, and 

 multi-valvular types. The boilers which 

 generate the steam vary over a wide 

 range of makes, from the most simple 

 to the most complicated and improved. 

 Coal is the fuel used generally through- 

 out the islands for these pumping sta- 

 tions, and its cost averages about $10 

 or a little less per ton. 



Perhaps the most interesting of all 

 the pumping works are those on the 

 Kihei plantation, adjoining the Ha- 

 waiian Sugar Company on the south. 

 Here numerous wells have been sunk 

 and extensive shafts and channels have 

 been constructed to develop a liberal 

 flow of water. At one of the stations 

 the capacity of the pumps is 17,560,000 

 gallons in 24 hours, and they were in- 

 stalled at an expense of $258,000. 



On the borderland of the wet and dry 

 portions of the Island of Maui is the 

 Haiku plantation, whose elevation va- 

 ries from 300 to over 1,200 feet. The 

 rainfall in this region materially assists 

 irrigation, and the headwaters of the 

 river on the far or wet side of the moun- 

 tain have with great difficulty been 

 diverted in canals to the fields on the 

 more fertile slope. Nevertheless, the 

 plantation authorities have installed 

 two pumps of a combined capacity of 

 9,500,000 gallons to assist in the irriga- 

 tion of the low r er levels and as a security 

 against a possible deficiency in the canal 

 supply. These pumps raise the water 

 to land 250 to 450 feet above the sea- 

 level. 



The development of this system of 



pumping shows a new use for this class 

 of machinery in a field to which it is 

 peculiarly adapted. Many irrigators 

 look upon such plants as expensive lux- 

 uries, and with reason, unless there is 

 a commensurate return for the large 

 amounts which must be invested. 



Exhaustive experiments at the island 

 station maintained by the Hawaiian 

 Sugar Planters' Association show that 

 certain well-established principles must 

 be kept in view in the irrigation of the 

 cane. More than two-thirds of the 

 sugar produced is by means of irriga- 

 tion. In the favorable, unirrigated 

 areas about 125,000 tons were produced 

 in 1900. On the leeward side of the 

 islands dependence on natural rainfall 

 supplies is impracticable, as experi- 

 ments show that areas depending on 

 rainfall alone produce only i ,600 pounds 

 of sugar per acre, while those treated 

 with irrigation in addition to the same 

 rainfall made 24,755 pounds to the acre, 

 a difference in favor of irrigation of 

 23,155 pounds. It can be seen from 

 these figures how such expensive sys- 

 tems of irrigation can be made to pay. 



The greatest faults to be overcome 

 in Hawaiian irrigation are those which 

 result from over-irrigation. In the first 

 place, the mistake is sometimes made of 

 irrigating the sugar-cane seed too freely, 

 thereby excluding the oxygen of the air 

 from the seeds and making germination 

 imperfect, and souring the soil. Dur- 

 ing the first months of the growth, this 

 fault of too much water, if persisted in, 

 will seriously affect the productiveness 

 of the crop. Moreover, all water used 

 in excess of the need soaks away and is 

 lost, and this must be guarded against 

 with the water supply at hand for irri- 

 gation purooses in Hawaii. As soon as 

 the artesian supply is too much drawn 

 upon, the water becomes brackish, and 

 salt is injurious, especially in those areas 

 where an alkaline condition of the soil 

 already exists. In draining through 

 the soil, moreover, the water carries off 

 many soil constituents upon which 

 plant-life depends for food. With alka- 

 line soils nothing but perfect under- 

 drainage will make irrigation a success, 

 particularly where brackish waters have 

 to be used. Enough water to leach out 



