47 



Division of Hydrography 



Honolulu, February 13, 1917. 



Board of Commissioners of Agriculture and Forestry. 



Gentlemen: — The following report of operations of the Divi- 

 sion of Hydrography during January, 1917, is submitted: 



Kauai. 



The regular monthly visit to the mauka measurement stations 

 revealed the fact that the December 18 flood, which destroyed 

 the Hanapepe river measurement station, also destroyed the 

 measurement station recently established on the Waiahuiu branch 

 of the Waimea river, including the new Gurley recording instru- 

 ment. 



Several staff gages were destroyed and, at most of the mauka 

 stations, much damage was done to the measurement sections in 

 the channels, these being filled with huge boulders and debris. 

 An estimate of the cost of repairing and replacing stations is 

 now being prepared and will be submitted as soon as possible. 



The U. S. Weather Bureau maximum and minimum thermo- 

 meters, recently established at Kokee, elevation 3,550 feet (in the 

 area suggested as a territorial camping place), showed a mini- 

 mum for January of 32° F. These instruments are established, 

 sheltered and operated in exact accordance with U. S. Weather 

 Bureau regulations. The minimum reading for December was 

 about 41° F. 



Twenty-nine stream and ditch measurement stations and 12 

 rainfall measurement stations were visited, and 17 discharge 

 measurements were made. Three stream measurement stations 

 were discontinued (destroyed by December flood). 



Oahu. 



To prevent the artesian well head measurement work being 

 suspended during the balance of the fiscal year ending June 

 30, 1917, this division has undertaken to keep up this work in 

 connection with the surface hydrometric work until some provi- 

 sion can be made by the 1917 Legislature of the Territory of 

 Hawaii relative to the future status of underground water in- 

 vestigations. 



Data obtained to date from the Hillebrand Glen run-off in- 

 vestigation show the following interesting facts. The total period 

 covered is from May 23, 1916, to January 31, 1917: 



Average daily flow, 530,000 gallons. 



Average percentage of run-off to rainfall, 22^%. 



Maximum percentage of run-off to rainfall, (January) 35%. 



