60 
SEEPAGE OR RETURN WATERS FROM IRRIGATION. 
the upper portions of the stream. The earlier canals, some built by 
the Moors before 1000, A D., were taken out from the lower por^ 
tions of the stream, the later ditches near the head. P 
The lower canals desired to close the upper ones. ' The latter 
returned £"?} Wa< f r that Was a PP lied b y them 511 irrigation 
returned to the river to a great extent, and thus had the effect of 
making the stream more constant in its flow, and, therefore, was as 
a whole advantageous for the lower users. During several years a 
system ot measurements was carried on at different places on the 
stream and included all the water that came into the stream 
iiougli the smaller tributaries. Measurements were made daily by 
e local officers Ihe valley is one the total length of which is 
32 000‘acr ‘ ke TO 7 mileS ’ and the total area irrigated is 
it ir° dt G T 1 16 cultlvat1011 consists largely of wheat beans 
alfalfa, meadows and gardens, with small quantities of potatoes and 
n : . biennial rotation is practiced which dates from the Moors. 
ram is usually watered three times, once at the time of sowing in 
November. Irrigation is practiced throughout the whole season, 
in the upper valley wheat is not watered. Beans are watered from 
the nuddle of July to the middle of September. From the data, 
obtained, M. \ igan reached the following conclusions : The return 
waters are derived from all irrigated lands of the valley, varying 
nessof‘If th , 6 n r0pS ’ a,n0Unt of water used each season, thick® 
aver Y, co, "P osltlon > and the slope of the impermeable 
layer He concludes that, in the bottom lands, which form a bed 
frrim it "u ^ the streani - and are abundantly watered, 
om the' first ot March, that the return waters from this'source are 
sufficient to compensate for the losses caused bv irrigation during 
the greatest part of the low water. He also concludes that, in the are! 
forming a strip two or three miles wide, with a very deep laver of 
permeable sod the return waters come to the surface only income 
unused infL fT** 5^ ° f the SpringS which are caused flow 
unused in the subsoil and return frequently to the sea. Oil these 
lands irrigation occasions considerable loss; hence he concludes 
that in case of an application for water right in the stream for 
shonH h d ‘f Che *’ whlcb are t0 be newly constructed, the concession 
ti e other 6 f , 6d ;f Ce P‘ emotionally. In case water is lacking in 
e otliei canals, then the new ones should be closed In general 
under the conditions existing in that valley of the Tet, irrigation at 
he upper portions of the stream with water taken at periods of high 
er > is beneficial to the lower portions of the stream. The water 
re , tu ™ s , t0 f he in such quantity that the • 
earn is net so low as if the irrigation had not been practiced. 
in ., So ™ e . of tbe measurements of the Poudre river have been cd ve n 
p qtbO ° ° ° gnCUltUral Ex P er iment Station Report, 1891, 
