Lawn Sprinkling Through Concealed Irrigation 



By Laurie Davidson Cox. 



The excessive cost of maintenance is one of the most 

 serious problem which confronts the park builder in the 

 climate of Southern California, writes Laurie Davidson 

 Cox, landscape architect, Park Department, Los Angeles, 

 Cal., in Tlie Aincrican City. This is because the mainte- 

 nance is continuous throughout the year, during 

 practically all of which time artificial irrigation must 

 be resorted to. Any eastern park official who has 

 struggled with a much used lawn during an August 

 drought will realize what ten months of such conditions 

 must mean to us here in Southern California. 



Four years ago wlien this department undertook, as 

 part of a progressive park system, the problem of re- 

 ducing mainte- 

 nance costs, the 

 question of 

 lawn irrigation 

 was seen to be 

 one of the chief 

 features of the 

 jiroblem. In 

 an attempt to 

 r e tl u c e this 

 item, recourse 

 was had to a 

 system making 

 use of fixed 

 sprinkler top^ 

 s u p p 1 i e il 

 b y u n d e r- 

 ground pipes. 

 The system 

 Mas worked 

 out in this de- 

 ]"artnient under 

 the direction of 

 the superin- 

 tendent, M r. 

 Frank Shearer, 

 and proved 

 very satisfac- 

 t o r y. Today 

 systems more 

 or less similar 

 are being wide- 

 ly used all over 

 Southern Cali- 

 fornia. 



UPPER ILLUSTR.\T10N SHOWS UNnERGROUND PIPE SYSTl:\l I 

 ILLUSTRATION SHOWS IT IN.\CTI\E. 



Since the first use of the system by the Park Depart- 

 nient here, there have been numerous new ideas brought 

 forward regarding the form of the sprinkler tops and 

 their arrangement. Some of these are of considerable 

 complexity, such, for e.xample, as the disappearing top 

 for use in shrubbery and flower beds. This rises to a 

 height of several feet to operate and drops below the 

 ground cut of sight when the water is shut off. The 

 simple fixed top is, however, the standard and a number 

 of such tops are on the market. These differ principally 

 in the amount of water wliich they distribute and the 

 pressure under wdiich they work. 



The newer forms of tops are designed so as to with- 

 stand weight and hard usage, such as that given by horse 

 and power motors. The earlier forms did not do so, 

 fnd much breakage of tops ensued. The general principle 

 now is to provide as a part of the top a protecting guard, 

 such as the one now used by this department and shown 



in the diagram. Uthers make use of a spring valve which 

 closes wdien the sprinkler is not in use and causes the 

 sprinkler to present a plain massive surface capable of 

 with.standing a heavy thrust or pressure. On account 

 of greater strength and toughness, brass or bronze is 

 now frequently used for the material in these tops, rather 

 than composition metal or cast iron, as formerly. 



In using the system for shrubbery and flowers a greater 

 variety of sprinkler tops is possible, as the top can be 

 kept above the ground and may be of more delicate con- 

 struction. For this work a sprinkler which distributes 

 the water so as to leave the walks or other adjacent areas 

 dry is desirable. The most ingenious form yet seen by 



the writer is 

 one making use 

 of gas jets set 

 slightly above 

 the ground and 

 arranged in the 

 grass or curb 

 border of the 

 bed. 



ISesides the 

 system making 

 use of buried 

 pipes and fixed 

 sprinkler tops, 

 there are sev- 

 e r a 1 systems 

 using pierced 

 pipe which lie 

 flush with the 

 surface of the 

 lawn. Of these 

 the best known 

 is the so-called 

 "Skinner sys- 

 tem," the de- 

 tails of which 

 are shown in 

 Diagram Num- 

 ber Two. The 

 system consists 

 m e r e 1 y of a 

 galvanized iron 

 !> i p e ( usually 

 ;''4 - i n c h is 

 used ) w i t h 

 minute holes punched 16 inches apart, laid flush with the 

 surface of the ground and provided with a patented union 

 and handle which permits the pipe to be rotated without 

 leakage. Such a system will sprinkle splendidly a strip 

 of lawn twenty feet on either side. The system is espe- 

 ciallv good for flower and shrub borders or for long, nar- 

 row strips of grass such as street parkings. It is much 

 cheaper to install than the underground system and dis- 

 tributes the water in a finer mist. It is, however, more 

 trouble to operate, and the labor cost of irrigation is 

 probably twice as .great as with the underground system. 

 The unilerground system as used by the Los Angeles 

 Park Department consists of a series of pipes laid in' 

 radiator circuits 12 to 15 inches deep in the ground, hav- 

 i^4 stand pipes with attached sprinkler tops placed flush 

 with the surface of the lawn at intervals of from 15 to 20 

 feet. The grass soon covers the tops, so that the system 

 when inactive is absolutely invisible. The tops do not 



