1 904 FORESTRY AND IRRIGATION 271 



the mature crop) are set free on all ation of the forest and the market con- 

 sides by the removal of all their imine- ditions. Theoretically, they should be- 

 diate neighbors which crowd them, ir- gin after the cover is established, say in 

 respective of the class to which they the tenth or twelfth year, and continue 

 belong. The rest of the stand is thinned in five or ten year intervals throughout 

 by grade A and made to serve as ground the period of greatest growth, 

 cover and keep the selected trees well In conclusion, let it be said that a thin- 

 pruned and full-boled. This may be ning never permanently breaks the for- 

 called ' ' selection thinning, ' ' and is des- est cover. In the heaviest D thinning 

 ignated as D A. It has given good re- the forest should not take longer than 

 suits in practice, the intermediate yield three to five years in recovering itself, 

 being excellent and the final yield of Of course, the degree of thinning de- 

 the best quality and quantity. pends entirely on species, age, and soil 

 The time for the first thinning and quality, but any permanent break in 

 the subsequent recurrence depends, like cover is a light increment cutting and 

 everything else in forestry, on the situ- belongs to a different question. 



RECLAMATION WORK IN NEW MEXICO. 



DESCRIPTION OF ONE OF THE FIRST PROJECTS 

 LIKELY TO BE TAKEN UP IN THIS TERRITORY. 



THE report of Mr. W. M. Reed, sion is in earth, and to provide for a 



Resident Engineer of the Serv- spillway here would be expensive and 



ice, is of particular interest by reason of would be always a source of annoyance 



the fact that it is probable the govern- if not danger. Two spillways or flush- 



ment will begin at an early date the ing gates are placed on the canal, each 



construction of an irrigation work at in solid rock, with their grade two feet 



one of the sites recommended by him. below the grade of the canal at that 



Apparently the most feasible project point. These spillways are provided 



discovered by Mr. Reed is on the Hondo with gates, not automatic, for these 



at a point nearly on the dividing line of gates are to be used only when the reser- 



the watersheds of Hondo River and the voir is full, or when it is desired to 



Black Water Arroyo. The reservoir flush the silting basins. The top of the 



site lies in a large natural depression gates will be below the embankment 



commonly called a dry lake, and has an grade, and will act as safety spillways 



area of 1,072 acres, and with no em- in the case of unexpected and unusual 



bankment would hold 11,480 acre feet, floods. 



The bottom of the lake is a heavy allu- The canal will have a seventy-foot 



vial deposit, and borings were satisfac- road bed, and an embankment will be 



tory as to its water-holding properties, placed at the lower side. The canal 



The perimeter is nearly all limestone, will enter the reservoir from a rock cut, 



and has the appearance of being as solid thus preventing any erosion. The out- 



and free from cavities as any limestone let canal will connect the lowest point 



formation, except at the places where in the reservoir site with the original 



fills are required. The sides are much bed of the river. The elevation at these 



higher than the proposed water line and points being the same, the canal is level, 



have rock on or near the surface. The bed of the Hondo will be used for 



Mr. Reed's plan for diverting the carrying the irrigating water for a dis- 



water is to make two canals of sufficient tance of about one mile. At this point 



size to carry all the flow of the river, it will be turned by a small concrete di- 



and to provide a spillway on the canal version dam into distributing canals on 



at a rock point 4,000 feet from the one side of the river. This point of 



river. The river at the point of diver- diversion is not the most suitable from 



