KTJKAL ENGINEERING. ,285 



per acre, while the aniui;il assessments to cover maintenance vary from $1 to $2 

 lier acre. 



Duty of water measiiremeuls are given for a large number of canals, covering 

 in some instances several years. Measurements for the Sunnyside Canal cover 

 7 years and show a constant decrease in the quantity of water used from 1898, 

 when the average depth used was 11.4 ft., to 1906, when the average depth 

 used was 0.5 ft. General statements for IS of the larger canals show varia- 

 tions in depths used of from 3 to 12J ft. 



The use of these large quantities of water, together with the leakage from 

 ditches, has injured much land and made drainage necessary in several sec- 

 tions. Seepage measurements on one canal showed losses of from 1 to 3 per 

 tvnt of the volume carried per mile of ditch. 



The report closes with a statement regarding the work of the Reclamation 

 Service in the Yakima Valley. 



Seepage and drainage, I, E. T. Tannatt and A. P. Anderson (Montana Sta. 

 UhI. Oo, Pit. (J3, pis. .'i). — This bulletin calls attention to the evils of over- 

 irrigation and leaky irrigation ditches and describes the drains installed upon 

 a part of the Montana Station farm at Bozeman. The held drained had a thin 

 top soil of muck and loam underlaid by gravel of vmdetermined depth. The 

 drains were first used, but it was found that the joints became cemented, proba- 

 I)ly by silt carried in the irrigation water, rendering the drains useless. Box 

 drains without bottoms were substituted and proved successful, while in addi- 

 tion they were cheaper than the tile drains. Detail drawings of the box drains 

 and a bill of materials are given. 



Reclamation of tide lands, .7. O. Wkight {('. ,S. Dept. A{/r., Office Expt. Htax. 

 Itpt. 1906, pp. 373-397. pis. 5. fif/s. 6). — This paper is a general statement regard- 

 ing the extent of tide lauds, their value when reclaimed, and methods of 

 reclamation. The soil of these marshes is composed of sediment mingled with 

 the remains of animal and vegetable life. Chemical analyses of numerous 

 sami)les and yields of crops grown on reclaimed tracts show that they are very 

 productive and that, with proper treatment, including the leaching out of excess 

 salt, they are extremely valuable. 



The general method of reclamation is diking to keep out tide water and 

 internal drainage. Where the variation between high and low tide is sufficient 

 drainage can be accomplished by the use of automatic tide gates which allow 

 the drainage water to escape at low tide. Where ftiis difference is small it is 

 necessary to pump the drainage water over the dikes. The dikes may be con- 

 structed by hand, with teams and scrapers, or with dredges, jdepending upon the 

 size necessary. The reclamation of these marshes has been successful where 

 dikes have Iteen properly constructed and protected, and failures can in most 

 cases be attrii)uted to neglect of the proper precautions. The essentials of a 

 dike are a wide berm between the water and the foot of the dike, flat slopes 

 I)roperly protected, and proper preparation of the foundation to insure a good 

 joint between the natural earth and the embankment. Slopes on the water side 

 should not be less than 3 to 1 and on the land side not less than 2 to 1. All 

 vegetable matter should be removed from the foundation and intercepting 

 ditches should be excavated aud refilled just inside of each toe of the dike. 



Dredges of different kinds are descril)ed and drawings and bills of material 

 for both concrete and timber tide gates are given. 



Object-lesson roads, !>. W. Page (IL >S'. Drpt. Ayr. Ycarhook 1906, pp. 137- 

 1')0, pis. //). — In this article Director I'age outlines the work of the Office of 

 Public Roads of this Department, showing that its work is divided into two 

 general classes — the economic questions of road management and the practical 

 features of road construction and maintenance. 



