SEEPAGE OR RETURN WATERS 
FROM IRRIGATION. 
BY L. G. CARPENTER. 
^^.. For convenience of reference , the principal paragraphs are numbered 
PAAA'j i TP or . tai T e '. §2 Relation to water applied. Poudre goq 
Effects linp t.n irHcofinn j nr *_ f i^ t'at) 1 e ~V II.) .. , .... ,, 30 
Effects due to irrigation,. 
The phenomena of return water,. 5 
The present measurements,....’ ” 0 
Methods of gaging,... 7 
Description of the Poudre valley,’. ” E ! E E"* 8 
Crops and irrigation. g 
Principal canals.. . . A 10 
Character of the stream, .. 77 
Average monthly flow (Table I.’)’.! ” ! ’.’.EE Temperature factor 
Conditions affecting measurement,. 12 " ‘ 
Diagram showing results (Fig. 2 ),............ 13 
Table showing relation between rainfall and 
times of gaging (Table II.),. 14 
Notes on the measurements,. ..... 15 
Detailed tables Poudre gagings — Summary 
of Poudre gagings (Table III ) .. 
Description of the Lower Platte,.16 
Lateral drainage,.. . 17 
Bed of Platte,. 18 
Location of irrigated land,!. AREA A. A! 19 
Complicating conditions. 
: _ • _.. ’ 
v _ __3Q 
Effect of temperature (Table Vl’li.j, . A.A" 31 
Rapidity of movement.. ...AS 32 
Direct evidence scarce, .E.EEEEEEE 32 
Case at Montrose,....A"... 33 
Observations quoted,_.A .AAA A A A* 34 
Rate is slow, .AA A AA.. 35 
French experiments,. A..A A. . 36 
Formula. . . 37 
gg 
Velocity through soils (Table IX ’’ .AAA' 
Losses from a canal,. A 39-40 
The rate of movement. ......... 41 
Case of the Hoover ditch,. A 42 
Other cases,.. A AA A 43 
Source of the increase,. AAA 44 
In rainy countries. A AA A A. 45 
No observations before irrigation,.* 45 
Soil percolation and evaporation,’Lawes and 
Gilbert,. 47 
Conditions in Colorado,. AA AA. A A A A 48 
I? C tn ctero1 ' rainfa "’ aJld Nation tVeVa^ 
o ^ -T_.*_/ tv • j’ *.* ** ‘ . 
Figure showing results of gagings’(Fig. 4) 
ISotes of measurements, ... . 23 
Detailed tables of, from 188^95-Summary’, 
(Table IV.). 
Irrigation of the Upper Platte A !. 24 
Seepage of Upper Platte (Table V.). .AAA 
Relation between seepage and area irrigated, 25 
Distribution of land and w 7 ater, Poudre vallev 
1894 (Table VI.) ... 
Comparison of the Lower Platte. A. A 27 
Conditions favorable to a large return 
Platte. 
in 
28 
. 49 
Underflow of lateral streams,. 50 
Measurements to determine,.. 51 
Case of the Bijou. A A! 52 
Table of measurements (Table X.) AAA A 
Inflow and irrigation, South Platte,.....’...”” 54 
Effect of irrigation at heads of streams on 
irrigation below. 55 
Are these results applicable elswher’eA .’... . . 56 
Italy, Utah, California. 56-58 
Other investigations and references,. ........ 59 
Conclusions. 59 
Acknowledgments,. A A AAA 61 
§ 1. In countries where irrigation is practiced, it is often the 
case that, though streams may be drained dry by the diversion of 
the waters into canals, not far below the stream will again be of 
considerable size, and this without the inflow of visible tributaries. 
§ 2. Phis may become of considerable economic importance, 
as it already has in the valleys whose measurements are here re¬ 
ported. In the valley of the Poudre, the seepage water is worth, 
at prices at which sales have already been made, from $300,000 to 
$o00,000 at the least, and the waters of the Platte from two to 
three million dollars. It is of corresponding importance in the val¬ 
leys of Clear Creek, St. Vrain, and others. Of such importance al- 
