SEEPAGE OR RETURN WATERS 
FROM IRRIGATION. 
BY L. G. CAKPENTER. 
For convenience of reference, the principal paragraphs are numbered: 
Economic importance. § 2 
Attributed to irrigation,. 3 
Effects due to irrigation,. 4 
The phenomena of return water,. 5 
The present measurements,. 6 
Methods of gaging,. 7 
Description of the Poudre valley,. 8 
Crops and irrigation,. 9 
Principal canals,.. 10 
Character of the stream,. 11 
Average monthly flow (Table I.). 
Condihons 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,. 19 
Complicating conditions,. 20 
Methods of irrigation,. 21 
Figure showing results of gagings (Fig. 4) .. 
Notes of measurements,. 23 
Detailed tables of, from 1889-95—Summary, 
(Table IV.). 
Irrigation of the Upper Platte. 24 
Seepage of Upper Platte (Table V.). 
Relation between seepage and area irrigated, 25 
DistriV>ution of land and water, Poudre valley, 
1894 (Table VI.) . . 
Comparison of the Lower Platte. 27 
Conditions favorable to a large return in 
Platte,. 28 
Relation to water applied, Poudre,.§29 
Comparison by sections (fl'abie VII.). 39 
Effect of temperature (Table VIII.),. 31 
Rapidity of movement. 32 
I>irect evidence scarce, . 32 
Case at Montrose,. 33 
Observations quoted,. 34 
Rate is slow, . 35 
French experiments,. 36 
Formula. 37 
Temperature factor. . 38 
Velocity throu.gh soils (Table IX.),. 
Losses from a canal,.39-40 
The rate of movement. 41 
Case of the Hoover ditch,. 42 
Other cases,. 43 
Source of the increase,. 44 
In rainy countries,.45 
No observations before irrigation,. 46 
Soil percolation and evaporation, Lawses and 
Gilbert,. 47 
Conditions in Colorado,. 48 
Character of rainfall, and relation to evapora¬ 
tion,. 49 
Underflow of lateral streams,. 50 
Measurements to determine,. 51 
Case of the Bijou. 52 
Table of measurements (Table X. j.. 
Inflow and irrigation. South Platte,. 54 
Effect of irrigation at heads of streams on 
irrigation below,. 55 
Are these results applicable elswhere ?. .56 
Italy, Utah, California. 56-58 
Other investigations and references,. 59 
Conclusions,. 60 
Acknowledgments,. 61 
§ 1. Til 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 tar below the stream will again be of 
considerable size, and this without the inflow of visible tributaries. 
§ 2. This may become of considerable economic importance, 
as it already has in the valleys wdiose measurements are here re¬ 
ported. In tlie valley of the Poudre, tlie seepage water is worth, 
at prices at which sales have already been made, from $300,000 to 
$500,000 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- 
