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DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, Diekctok

Water-supply Paper 358

WATER RESOURCES OF THE RIO GRANDE BASIN

1888-1913

BY

ROBERT FOLLANSBEE and H. J. DEAN

INCLUDING

SURFACE WATER SUPPLY OF THE UNITED STATES, 1913 PART VIII, WESTERN GULF OF MEXICO BASJNS

ROBERT FOLLANSBEE, W. W. FOLLETT AND GLENN A. GRAY

WASHINGTON

GOVERNMENT PRINTING OFFICE 1916

DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, DIRECTOR

Water- Supply Paper 358

WATER RESOURCES OF THE

RIO GRANDE BASIN JJ^^^ 1888-1913 ^n

BY

ip^

ROBERT FOLLANSBEE and H. J. DEAN

INCLUDING

SURFACE WATER SUPPLY OF THE UNITED STATES, 1913 PART VIII, WESTERN GULF OF MEXICO BASINS

ROBERT FOLLANSBEE, W. W. FOLLETT AND GLENN A. GRAY

WASHINGTON

GOVERNMENT PRINTING OFFICE 1915

fl

D. OF 9.

JUN 26 J9)5

^s

^

CONTENTS.

Page.

Scope of report 9

Cooperation and assistance 10

Bibliography 11

Definition of terms 12

Convenient equivalents 13

Explanation of data 15

Accuracy of field data and computed results 17

General features of the Rio Grande drainage basin 18

Location and boundaries 18

Topography 19

Closed basins 19

San Luis Valley 19

Basins between Rio Grande valley and Pecos basin 20

Basins west of Rio Grande 21

Basin east of Pecos River in New Mexico 21

Basins in Mexico 21

Precipitation 21

Periods covered by records 21

Distribution 23

Relation between precipitation and run-off 24

Forestation 25

Population 26

The river 28

General features 28

Tributaries 30

Gaging station records 31

Rio Grande at Thirtymile Bridge, near Creede, Colo 31

Rio Grande near Creede, Colo 37

Rio Grande near Del Norte, Colo 46

Rio Grande at Alamosa, Colo 75

Rio Grande near Lobatos, Colo 79

Rio Grande at Embudo, N. Mex 98

Rio Grande near Buckman, N . Mex 120

Rio Grande near San Marcial, N . Mex 141

Rio Grande near El Paso, Tex 168

Rio Grande near Fort Hancock, Tex 199

Rio Grande above Presidio, Tex 203

Rio Grande below Presidio, Tex 223

Rio Grande near Langtry, Tex 245

Rio Grande near Devils River, Tex 265

Rio Grande at Eagle Pass, Tex 284

Rio Grande near Laredo, Tex 306

Rio Grande near Roma, Tex 316

Rio Grande near Brownsville, Tex 328

3

CONTENTS.

Clear Creek basin 339

Clear Creek near Creede, Colo 339

South Fork of Rio Grande basin 341

South Fork of Rio Grande at South Fork, Colo 341

San Luis Creek basin 346

General features 346

Gaging station records 347

San Luis Creek at Villa Grove, Colo 347

San Luis Creek near Villa Grove, Colo 349

Kerber Creek near Villa Grove, Colo 350

Saguache River near Saguache, Colo 352

Rio Alamosa basin 355

General features 355

Gaging station records 357

Rio Alamosa near Monte Vista, Colo 357

Rio Alamosa at Terrace reservoir, near La Jara, Colo 359

Conejos River basin 362

General features 362

Gaging station records 363

Conejos River near Mogote, Colo 363

Rio San Antonio near Ortiz, Colo 375

OostUla Creek basin 376

General features 376

Gaging station records 376

Costilla Creek near mouth. New Mexico 376

Rio Colorado basin 378

General features 378

Gaging station records 378

Rio Colorado above Questa, N. Mex 378

Rio Colorado near Questa, N. Mex 380

Rio Colorado below Questa, N. Mex. 382

Rio Hondo basin 386

General features 386

Gaging station records 386

Rio Hondo near Arroyo Hondo, N . Mex 386

Rio Taos basin .• 390

General features 390

Gaging station records 390

Rio Pueblo de Taos near Taos, N. Mex 390

Rio Taos at Los Cordovas, N . Mex 395

Rio Lucero near Taos, N . Mex 400

Rio Fernando de Taos near Taos, N . Mex 405

Chama River basin 407

General features 407

Gaging station records 408

Chama River at Chama, N . Mex 408

Chama River at Park View, N. Mex 410

Chama River at Abiquiu, N. Mex 412

Chama River near Chamita, N. Mex 414

Brazos River at Brazos, N. Mex 415

Horn River near Canjilon, N. Mex 418

Rio Vallecitos at Vallecitos, N. Mex 420

CONTENTS. 5

Pa?e.

Santa Fe Creek basin 424

General features 424

Gaging station records 425

Santa Fe Creek at Monument Rock, near Santa Fe, N. Mex 425

Santa Fe Creek above reservoir near Santa Fe, N . Mex 426

Santa Fe Creek at Santa Fe, N. Mex 429

Arroyo Hondo near Santa Fe, N . Mex 435

Rio Puerco basin 437

General features 437

Gaging station records 438

Rio Puerco at Rio Puerco, N. Mex 438

Rio Puerco near La Joya, N . Mex 441

Bluewater Creek near Bluewater, N. Mex 443

Bluewater Creek at Grants, N. Mex 446

San Jose River near Suwanee, N. Mex 448

Pecos River basin 452

General features 452

The Pecos flood of 1904 453

Gaging station records 455

Pecos River near Cowles, N. Mex 455

Pecos River near Anton Chico, N . Mex 460

Pecos River at Santa Rosa, N. Mex 465

Pecos River near Guadalupe, N. Mex 473

Pecos River near Fort Sumner, N . Mex 475

Pecos River near Roswell, N. Mex 485

Pecos River near Dayton, N. Mex 488

Pecos River near Lakewood, N. Mex 501

Pecos River at Avalon, N. Mex 507

Pecos River at Carlsbad, N . Mex 510

Pecos River near Pecos, Tex 516

Margueretta flume near Pecos, Tex. 529

West Valley ditch near Pecos, Tex 538

Pecos River near Moorhead, Tex 539

Gallinas River basin 560

General features 560

Gaging station records 561

GalUnas River near Las Vegas, N . Mex 561

South Fork of Gallinas River near El Porvenir, N . Mex 574

Hondo River basin 578

General features 578

Gaging station records 579

Hondo River at Hondo reservoir site, N. Mex 579

Inlet canal at Hondo reservoir, near Roswell, N . Mex 583

Hondo River at Roswell, N. Mex 585

Rio Ruidoso near Ruidoso, N. Mex 587

Rio Ruidoso near Glencoe, N . Mex 588

Penasco River basin 589

General features. 589

Gaging station records 590

Penasco River at Elk, N. Mex 590

Penasco River near Elk, N. Mex 591

Penasco River near Dayton, N. Mex 592

6 CONTENTS.

Pecos River basin Continued. Page.

Delaware River basin 595

General features 595

Gaging station records 595

Delaware River near Malaga, N. Mex 595

Devils River basin 598

General features 598

Gaging station records. 599

Devils River at Devils River, Tex 599

Mexican tributaries 618

Rio Salado naar Guerrero, Tamaulipas, Mexico 618

Rio San Juan near La Quemada and Santa Rosalia ranch, Tamaulipas,

Mexico 630

Closed basins 643

Mimbres River basin 643

General features 643

Gaging station records 643

Mimbres River near Faywood, N. Mex 643

Lampbright Draw near Santa Rita, N. Mex 651

Whitewater Draw at Hurley, N. Mex 654

Cameron Creek at Fort Bayard, N. Mex 654

Cameron Creek near Hurley, N. Mex 657

Stevens Creek near Fort Bayard, N. Mex 658

Rio de Arena near Hurley, N. Mex 662

Flood on Cameron Creek and Rio de Arena, August 10-14, 1913 662

Closed basins between Rio Grande and Pecos River 663

General features 663

Gaging station records 664

Rio Tularosa at Mescalero, N. Mex 664

Rio Tularosa near Bent, N. Mex 665

Rio Tularosa near Tularosa, N. Mex 666

Rio La Luz near La Luz, N. Mex 667

Rio La Luz at La Luz, N. Mex 669

Rio Fresnal near Mountain Park, N. Mex 671

Miscellaneous measurements 673

Seepage 679

Scope of investigations 679

Studies on the Rio Grande in Colorado 680

The measurements 680

Interpretation of results 683

Studies on the Rio Grande in New Mexico 684

The measurements 684

Points selected 684

Lobatos to San Marcial 684

Lobatos to El Paso 685

Lobatos station to Embudo 687

Interpretation of results 688

Studies on Chama River 690

Evaporation 694

Theory of evaporation 694

Methods of measurement 695

CONTENTS. 7

Evaporation Continued. Page.

Records of evaporation G96

Fort Bliss G96

Lake A valon 097

Santa Fe G97

Records from pans set in the ground (598

Sedimentation G99

Silt in Rio Grande water G99

Measurements of silt G99

Relation between weight and volume of silt 701

Records of silt determination at El Paso and San Marcial 702

Total silt carried in suspension past San Marcial 713

Sediment moving on bottom of river 715

Sedimentation in Pecos River 715

Index 717

ILLUSTRATIONS.

Plate I . Typical gaging stations 16

II. Price current meters 17

III. Map of Rio Grande drainage basin showing location of gaging sta- tions and mean annual precipitation in New Mexico and Texas ... 18

WATER RESOURCES OF THE RIO GRANDE BASIN, 1888- 1913, INCLUDING SURFACE WATER SUPPLY OF THE WESTERN GULF OF MEXICO BASINS, 1913.

By Robert Follansbee and H. J. Dean.

SCOPE OF REPORT.

This volume, which is one of a series of 12 reports presenting results of measurements of flow made on streams in the United States during the year 1913, includes all data concerning the Rio Grande and its tributaries collected prior to September 30 of that year.

Systematic study of run-off in the Rio Grande basin was begun by the Federal Government near Embudo, N. Mex., soon after the passage of the act of October 2, 1888, which authorized the organiza- tion of the irrigation survey under the direction of the United States Geological Survey. A camp of instruction for hydrographers was estabhshed near Embudo, and at this camp and the gaging station near by, the methods of stream measurements now in general use were systematized. In the spring of 1889 additional stations were estab- lished on the Rio Grande near Del Norte, Colo., and El Paso, Tex. From this beginning the work of measuring the waters of the Rio Grande basin has been expanded not only by the Geological Survey acting alone but by the Survey in cooperation with the American section of the International Water Commission ^ and the State engineers of Colorado and New Mexico. At the end of September, 1913, records had been obtained at 93 gaging stations.

The present report contains not only all data concerning stream flow in the Rio Grande basin collected by the Survey and cooperating parties but also records furnished by individuals connected with private interests. Most of the records here assembled have been taken from the publications of the Geological Survey, but original estimates have been revised where later data have indicated errors. The most notable necessity for revisions was in the older estimates of winter flow of the Rio Grande at Del Norte and Lobatos, the fig- ures given in the present report being considerably lower than those first published. Tables of daily discharge not heretofore pubhshed have been supplied from the original computations.

1 Prior to July 1, 1910, International Boundary Commission.

10 WATER RESOURCES OF RIO GRANDE BASIN, 1888-1913.

The drainage area is stated in connection with the run-off data for only a few of the stations, and no estimates of run-off per square mile have been made, for the maps for the greater part of the basin are so poor and the unit run-off for different areas varies between limits so wide that such estimates would be of little value.

The results of studies of precipitation, evaporation, and sedimen- tation as factors in determining the value of reservoir sites for storage of flood waters, on which future development must largely depend, are also presented in this report.

COOPERATION AND ASSISTANCE.

The American section of the International Water Commission began the work of stream gaging in 1897, by taking over the station at El Paso, Tex., formerly maintained by the Geological Survey. In 1900 a number of stations on the lower Rio Grande and tributaries below El Paso were estabhshed by the American and Mexican sections of the Commission, and in 1901 the station on the Rio Grande at San Marcial was taken over from the Geological Survey. These stations have been maintained to the present time under the immediate direction of W. W. FoUett, United States consulting engineer, through whom the chairman of the commission has furnished the records and to whom special acknowledgments are due.

A large part of the field data for the Pecos River basin was furnished by the United States Reclamation Service, by whom the stations were maintained.

Since 1909 the State engineer of Colorado has cooperated in the maintenance of the stations in Colorado and for 1912 and 1913 he has furnished all field data.

From 1907 to 1912 the work in New Mexico was carried on under the immediate supervision of the Territorial engineer. During the later part of 1912 a cooperative agreement was made with the State engineer and an office of the Geological Survey was established at Santa Fe in connection with the State engineer's office.

Acknowledgments are due also to the State engineers of Colorado and New Mexico for cooperation in making a complete seepage inves- tigation of the Rio Grande from Del Norte, Colo., to El Paso, Tex., for use in this report.

The United States Forest Service has prepared the data used in compiling the statements regarding forestation in the drainage basin.

Mr. W. L. Rockwell, irrigation engineer, Department of Agriculture, furnished the records of evaporation at the United States Experiment farm near San Antonio, Texas.

Mr. R. H. Forbes, director of the Agricultural Experiment Station at Tucson, Ariz., furnished the records of evaporation near Phoenix, Ariz.

BIBLIOGEAPHY. 11

Acknowledgments are also due to a number of corporations and indi\dduals for furnishing records, as noted in connection with each station affected.

The writers have assembled and reviewed the stream-flow data here presented and have made such changes in previously published figures as were necessary to reconcile apparent discrepancies. They have also reviewed and discussed the results of investigations of pre- cipitation, seepage, evaporation, and sedimentation.

BIBLIOGRAPHY.

The following publications, other than stream-flow reports of the United States Geological Survey, have been used in preparing the data presented in this report :

TOPOGRAPHY AND GEOLOGY.

Fisher, C. A., Preliminary report on the geology and underground waters of the Roswell artesian area, New Mexico: U. S. Geol. SiU'vej' Water-Supply Paper 158, 1906.

FoLLETT, W. W. , A study of the use of water for irrigation on the Rio Grande del Norte : Internat. (Water) Boundary Comm., Proc, pp. 284-323, 1903.

Hill, R. T., and Vaughan, T. W., Geology of the Edwards Plateau and Rio Grande plain adjacent to Austin and San Antonio, Tex., with special reference to the occurrence of underground waters: U. S. Geol. Survey Eighteenth Ann. Rept., pt. 2, 1897.

Johnson, W. D., The high plains and their utilization: U. S. Geol. Survey Twenty- first Ann. Rept., pt. 4, 1901, continued in Twenty-second Ann. Rept., pt. 4, 1902.

Lee,W. T., Water resources of the Rio Grande valley in New Mexico and their develop- ment: U. S. Geol. Survey Water-Supply Paper 188, 1907.

Meinzer, O. E., Geology and water resources of Estancia Valley, New Mexico, with notes on ground-water conditions in adjacent parts of central New Mexico: U.S. Geol. Survey Water-Supply Paper 275, 1911.

Geology and water resources of Tularosa Basin, New Mexico: U. S. Geol. Sur- vey Water-Supply Paper 343, 1914.

Richardson, G. B., U. S. Geol. Survey Geol. Atlas, El Paso folio (No. 166); 1909.

Siebenthal, C. E., Geology and water resources of San Luis Valley, Colorado: U. S, Geol. Survey Water-Supply Paper 240, 1910.

Slighter, C. S., Observations on ground waters of Rio Grande valley: U. S. Geol. Survey Water-Supply Paper 141, 1905.

precipitation.

Summary of climatologic data for the United States: U. S. Dept. Agr., Weather

Bureau, sections 1, 2, 3, 4, 5, 6, 7, and 9. U. S. Dept. Agr., Weather Bureau, Annual summaries, 1909, 1910, 1911, and 1912.

population.

Thirteenth Census of the United States, 1910.

seepage.

State engineer of Colorado, Tenth, Thirteenth, and Fourteenth Biennial reports.

12 WATER RESOURCES OF RiO GRANDE BASIN, 1888-1913.

EVAPORATION.

BiGELOw, F. H., A provisional statement regarding the total amount of evaporation

by months at 23 stations in the United States, 1909-10, U. S. Dept. Agr., Weather

Bureau. BiGELOw, F. H., A manual for observers in climatology and evaporation: U. S. Dept.

Agr., Weather Bureau, 1909. Colorado Experiment Station, Second Ann. Rept., p. 70; Third Ann. Rept., p. 102. Kimball, H. H., Evaporation observations in the United States. Newell, F. H., Evaporation at Fort Bliss, Tex. : U. S. Geol. Survey Fourteenth Ann.

Rept., pt. 2, p. 154, 1894.

sedimentation.

FoLLETT, W. W., Silt in the Rio Grande: International Water Commission, Proc,

1913. Powell, J. W., Sedimentin the Rio Grande: U. S. Geol. Survey Eleventh Ann. Rept.,

pt. 2, 1891. Reed, W.M., Siltsiuvey on Pecos River: U. S. Reel. Service Third Ann. Rept., 1905. Stabler, Herman, Some stream waters of the western United States with chapters

on sediment carried by the Rio Grande and the industrial application of water

analyses: U. S. Geol. Survey Water-Supply Paper 274, 1911.

DEFINITION OF TERMS.

The volume of water flowing in a stream the "run-off" or "dis- charge"— is expressed in various terms, each of which has become associated with a certain class of work. These terms may be divided into two groups (1) those which represent a rate of flow, as second- feet, gallons per minute, miner's inches, and run-off in second-feet per square mile, and (2) those which represent the actual quantity of water, as run-off in depth in inches, and acre-feet. The units used in this series of reports are second-feet, second-feet per square mile, run-off in depth in inches, and acre-feet. They may be defined as follows :

"Second-foot" is an abbreviation for cubic foot per second and is the unit for the rate of discharge of water flowing in a stream 1 foot wide, 1 foot deep, at a rate of 1 foot per second. It is generally used as a fundamental unit from which others are computed by the use of the factors given in the accompanying table of equivalents.

"Second-feet per square mile" is the average number of cubic feet of water flowing per second from each square mile of area drained, on the assumption that the run-off is distributed uniformly both as regards time and area.

"Run-off (depth in inches)" is the depth to which the drainage area would be covered if all the water flowing from it in a given period were conserved and uniformly distributed on the surface. It is used for comparing run-off with rainfall, which is usually expressed in depth in inches.

An "acre-foot" is equivalent to 43,560 cubic feet and is the quan- tity required to cover an acre to the depth of 1 foot. The term is commonly used in connection with storage for irrigation.

WATER BESOUECES OF EIO GEANDE BASIN, 1888-1913. CONVENIENT EQUIVALENTS.

13

The following is a list of convenient equivalents for use in hydraulic computations :

Table for converting discharge in second-feet per square mile into run-off in depth in inches

over the area.

Discharge

(second-feet

per square

mile).

Run-off (depth in

inches).

1 day.

28 days.

29 days.

30 days.

31 days.

1

0. 03719 . 07438 .11157 . 14876 . 18595 . 22314 . 26033 .29752 .33471

1.041 2.083 3.124 4. 165 5. 207 6.248 7.289 8.331 9.372

1.079 2.157 3.236 4.314 .5.393 6.471 7.5.50 8.628 9.707

1.116 2.231 3.347 4.463 5.578 6.694 7.810 8.926 10.041

1. 1.53 2.306 3.459 4.612 5.764 6.917 8.070 9.223 10. 376

2

3

4

5

6

7

8

9

Note.— For part of month multiply the value for 1 day by the number of days.

Table for converting discharge in second-feet into run-off in acre-feet.

Discharge (second- feet).

Run-ofl (acre-feet).

1 day.

28 days.

29 days.

30 days.

31 days.

1

1.983 3.967 5.950 7.934 9.917 11.90 13.88 15. 87 17.85

55.54 111.1 166.6 222.1

277.7 333.2 388.8 444.3 499.8

57.52 115.0 172.6 230.1 287.6 345.1 402.6 460.2 517.7

59.50 119.0 178.5 238. 0 297.5 357.0 416.5 476.0 535.5

61.49 123.0 184.5 246.0 307.4 368.9 430.4 491.9 5.53. 4

2

3

4

5

6

7

8

9

Note. For pai't of month multiply value for 1 day by the number of days.

Table for converting discharge in second-feet into run-off in millions of cubic feet.

Discharge (second- feet).

Run-ofl (millions of cubic feet).

Iday.

28 days.

29 days.

30 days.

31 days.

1

0.0864 .1728 .2592 .3456 .4320 .5184 .6048 .6912 .7776

2.419 4.838 7.257 9.676 12.10 14.51 16.93 19.35 21.77

2.506 5.012 7.518 10.02 12.53 15.04 17.54 20.05 22.55

2.592 5.184 7.776 10.37 12.96 15.55 18.14 20.74 23.33

2.678 5.356 8.034 10.71 13.39 16.07 18. 75 21.42 24. 10

2

3

4

5

6

7

8

9

Note. For part of month multiply the value for one day by the number of days.

14 WATER EESOUKCES OF RIO GRANDE BASIN, 1888-1913.

Table for converting discharge in second-feet into run-off in millions of gallons.

Discharge (second- feet).

Run-off (millions of gallons).

1 day.

28 days.

29 days.

30 days.

31 days.

1

0. 6463

1.293

1.939

2.585

3.232

3.878

4.524

5. 170

5.817

18.10 36.20 54.30 72.40 90.50 108.6 126.7 144.8 162.9

18.74 37.48 56.22 74.96 93.70 112.4 131.2 149.9 168.7

19.39 38.78 58.17 77.56 96.95 116.3 135.7 155.1 174.5

20.04 40.08 60.12 80.16 100.2 120.2 140.3 160.3 180.4

2

3

4

5

6

7

8

9

Note. For part of month multiply the value for one day by the number of days.

Table for converting velocity in feet per second into velocity in miles per hour.

flfootper second=0.681818 mile per hour, or two-thirds mile per hour, very nearly; 1 mile per hour =1.46666 feet per second. In computing the table the values 0.68182 and 1.4667 were used.]

Feet per second

Miles per hour for tenths of foot per second.

(units).

0

1

2

3

4

5

6

7

8

9

0

0.000 .682 1.36 2.05 2.73 3.41 4.09 4.77 5.45 6.14

0.068 .750 1.43 2.11 2.80 3.48 4.16 4.84 5.52 6.20

0.136 .818 1.50 2.18 2.86 3.55 4.23 4.91 5.59 6.27

0.205 .886 1.57 2.25 2.93 3.61 4.30 4.98 5.66 6.34

0.273 .955 1.64 2.32 3.00 3.68 4.36 5.05 5.73 6.41

0.341 1.02 1.70 2.39 3.07 3.75 4.43 5.11 5.80 6.48

0.409 1.09

1.77 2.45 3.14 3.82 4.50 5.18 5.86 6.55

0.477

1.16

1.84

2.52

3.20

3.89

4.57

5.25

5.93

6.61

0.545

1.23

1.91

2.59

3.27

3.95

4.64

5.32

6.00

6.68

0.614

1

1.30

2

1.98

3

2.66

4

3 34

5

4.02

6

4 70

7

5 39

8

6.07

9

6 75

1 second-foot equals 40 California miner's inches (law of March 23, 1901).

1 second-foot equals 38.4 Colorado miner's inches.

1 second-foot equals 40 Arizona miner's inches.

1 second-foot equals 7.48 United States gallons per second; equals 448.8 gallons per minute; equals 646,317 gallons for one day.

1 second-foot for one year covers 1 square mile 1.131 feet or 13.572 inches deep.

1 second-foot for one year equals 31,536,000 cubic feet.

1 second-foot equals about 1 acre-inch per hour.

1 second-foot for one day equals 86,400 cubic feet.

1,000,000,000 (1 United States billion) cubic feet equals 11,570 second-feet for one day.

1,000,000,000 cubic feet equals 414 second-feet for one 28-day month.

1,000,000,000 cubic feet equals 399 second-feet for one 29-day month.

1,000,000,000 cubic feet equals 386 second-feet for one 30-day month.

1,000,000,000 cubic feet equals 373 second-feet for one 31-day month.

100 California miner's inches equals 18.7 United States gallons per second.

100 CaUfomia miner's inches for one day equals 4.96 acre-feet.

100 Colorado miner's inches equals 2.60 second-feet.

100 Colorado miner's inches equals 19.5 United States gallons per second.

100 Colorado miner's inches for one day equals 5.17 acre-feet.

100 United States gallons per minute equals 0.223 second-foot.

100 United States gallons per minute for one day equals 0.442 acre-foot.

1,000,000 United States gallons per day equals 1.55 second-feet.

EXPLANATION OF DATA. 15

1,000,000 United Statea gallons equals 3.07 acre-feet.

1,000,000 cubic feet equals 22.95 acre-feet.

1 acre-foot equals 325,850 gallons.

1 inch deep on 1 square mile equals 2,323,200 cubic feet.

1 inch deep on 1 square mile equals 0.0737 second-foot per year.

1 foot equals 0.3048 meter.

1 mile equals 1.60935 kilometers.

1 mile equals 5,280 feet.

1 acre equals 0.4047 hectare.

1 acre equals 43,560 square feet.

1 acre equals 209 feet square, nearly.

1 square mile equals 2.59 square kilometers.

1 cubic foot equals 0.0283 cubic meter.

1 cubic foot of water weighs 62.5 pounds.

1 cubic meter per minute equals 0.5886 second-foot.

1 horsepower equals 550 foot-pounds per second.

1 horsepower equals 76.0 kilogram-meters per second.

1 horsepower equals 746 watts.

1 horsepower equals 1 second-foot falling 8.80 feet.

1 J horsepower equals about 1 kilowatt.

_ , , ^ ^ ... Sec.-ft.X fall in feet . ,

To calculate water power quickly: ^i =net horsepower on water

wheel realizing 80 per cent of theoretical power.

EXPLANATION OF DATA.

The data presented in this report cover the years beginning October 1 and ending September 30, and not, as in previous reports, the calendar years. At the first of January in most parts of the country a large amount of precipitation for the preceding three months is stored, either as ground water in the form of snow, or in lakes. This stored water passes off in the streams during the spring break-up. At the end of September the only stored water available for run-off in the streams is possibly a small amount held in ground storage. Therefore, the run-off for a year, beginning with October 1, is practically all derived from precipitation occurring within that year.

The use of this climatic year in studies of stream flow is applicable only to work in the Temperate Zone, as south of about the twenty- eighth parallel of latitude precipitation is greatest during the sum- mer months. The effect of the rainy season in Mexico is shown in the run-off data for all stations on the Rio Grande below El Paso, Tex.

For each regular current-meter gaging station the following data, so far as available, are given: Description of the station, list of dis- charge measurements, table of daily gage heights, table of daily dis- charge, table of monthly and yearly discharge and run-off. For sta- tions located at weirs or dams the gage-height table is usually omitted

In addition to statements regarding the location and installation of current-meter stations the descriptions give information in regard to

16 WATER EESOUECES OP EIO GEANDE BASIN, 1888-1913.

any conditions that may affect the constancy of the relation of gage height to discharge, covering such points as ice, logging, shifting chan- nels, and backwater; also information regarding diversions which decrease the total flow at the measuring section. Statements are also made regarding the accuracy of the data.

The table of daily gage heights records the daily fluctuations of the surface of the river as found from the mean of the gage readings taken each day, usually in the morning and in the evening. The gage height given in the table represents the elevation of the surface of the water above the zero of the gage. All gage heights affected by the presence of ice in the streams or by backwater from obstructions are pubhshed as recorded, with suitable footnotes. The rating table is not apphcable for such periods unless the proper corrections to the gage heights are known and applied. Attention is called to the fact that the zero of the gage is placed at an arbitrary datum and has no relation to zero flow or the bottom of the river. In general the zero is located somewhat below the lowest known flow, so that readings of negative values shall not occur.

The discharge measurements and gage heights are the base data from which rating tables, daily discharge tables, and monthly dis- charge tables are computed.

The rating tables gives, either directly or by interpolation, the dis- charge in second-feet corresponding to every stage of the river recorded during the period for which it is applicable. It is not published in this report, but can be determined from the tables of daily gage heights and daily discharge as follows :

First plot the discharge measurements for the current and earlier years on cross-section paper, with gage heights in feet as ordinates and dicharge in second-feet as abscissas. Then tabulate a number of gage heights taken from the daily gage-height table for the com- plete range of stage given and the corresponding discharges for the days selected from the daily discharge table and plot the values on cross-section paper. The last points plotted wiU define the rating curve used and will He among the plotted discharge measurements. After drawing the rating curve a table can be developed by scaling off the discharge in second-feet for each tenth foot of gage height. These values should be so adjusted that the first difference shall always be increasing or constant except for known backwater periods.

The table of daily discharge gives the discharge in second-feet corresponding to the observed gage heights as determined from the rating tables.

In the table of monthly discharge, the colunm headed "Maximum" gives the mean flow, as determined from the rating table, for the day when the mean gage height was highest. As the gage height is the

U. S. GEOLOGICAL SURVEY

WATER-SUPPLY PAPER 368 PLATE II

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iLEJi'.lLiil.-!al:.aiJfl 'Bi '7l S, ")i 'Fi2'l' i'3! i-^l 4 T.: c 7i 'f^l '3| 'Fj^li ,:2t '3[

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PRICE CURRENT METERS.

ACCURACY AND RELIABILITY OF FIELD DATA. 17

mean for the clay, it does not indicate correctly the stage when the water surface was at crest height, and the corresponding discharge was consequently larger than given in the maximum column. Like- ^vise in the column of ''Minimum" the quantity given is the mean flow for the day when the mean gage height was lowest. The column headed ''Mean" is the average flow in cubic feet for each second dur- ing the month. On this the computations for the remaining columns, which are defined on page 12, are based.

The field methods used in the collection of the data presented in this series of reports are described in the introductory sections of United States Geological Survey Water-Supply Papers 261 to 272, inclusive, "Surface water supply of the United States, 1909."

Plate I shows typical gaging stations. Plate II shows current meters used in the work.

ACCURACY OF FIELD DATA AND COMPUTED RESULTS.

The accuracy of stream-flow data depends (1) on the permanence of channel and of the relation between discharge and stage, and (2) on the accuracy of observation of stage measurements of discharge, and interpretation of data.

In order to give engineers and others information regarding the probable accuracy of the computed results, footnotes are added to the daily discharge tables, stating the probable accuracy of the rating cin-ves used, and an accuracy column is inserted in the monthly dis- charge table. For the rating curves "well defined" indicates, in gen- eral, that the rating is probably accurate within 5 per cent; "fairly well defined," within 10 per cent; "poorly defined" or "approxi- mate," within 15 to 25 per cent. These notes are very general and pre based on the plotting of the individual measurements with refer- ence to the mean rating curve.

The accuracy column in the monthly discharge table does not apply to the maximum or minimum nor to any individual day, but to the montlily mean. It is based on the accuracy of the rating, the probable reliability of the observer, and knowledge of local conditions. In this column A indicates that the mean monthly flow is probably accurate within 5 per cent; B, within 10 per cent; C, within 15 per cent; D, within 25 per cent. Special conditions are covered by foot- notes.

In general the base data collected each year by the Survey engineers are published not only to comply with the law but to aflord any engineer the means of examining and adjusting to his own needs the results of the computations. The table of montlily discharge is so arranged as to give only a general idea of the flow at the station and should not be used for other than preliminary estimates. The deter-

41823° wsp 358—15—2

18 WATER RESOURCES OF RIO GRANDE BASIN, 1888-1913.

minations of daily discharge allow more detailed studies of the varia- tion in flow by which the period of deficiency may be determined.

It should be borne in mind that the observations in each succeeding year may be expected to throw new light on data already collected and published.

GENERAL FEATURES OF THE RIO GRANDE DRAINAGE

BASIN.

LOCATION AND BOUNDARIES.

The area nominally belonging to the Rio Grande basin comprises the San Luis Valley and the region westward to the Continental Divide in Colorado, the greater part of New Mexico (except the western fifth of the State, and an area in the northeast corner approxi- mately 140 miles square), the western panhandle region in Texas, and a comparatively narrow strip along the lower river; in Mexico it comprises the greater part of the State of Chihuahua, large parts of Coahuila and Nuevo Leon, and small parts of Durango and Tamauhpas. (See PL III.)

In Colorado the boundaries of the basin are clearly marked by the almost continuous ring of mountains separating it from the Arkansas basin on the east and the Colorado basin on the north and west.

In New Mexico the boundaries are much less sharply defined, especially on the western border which reaches the high plateaus or mesas that characterize the greater part of the western section of the State and that commonly are either without surface drainage channels or form closed basins draining toward the center. In general, however, the western boundary may be said to coincide with the Cejita Blanca Range, Chacre Mesa, Zuni Mountains, and the west end of the Datil and Black ranges. From the northeast corner of Grant County the boundary line runs southwest to Bear Mountain, whence it takes a southerly direction to the Mexican Hne. The east- ern boundary in New Mexico is more clearly marked. As far south as Las Vegas it consists of the extension of the Sangre de Cristo Range; southeastward from Las Vegas it is well defined by the divides between the fines of natural drainage, until it reaches the high plateau region in Roosevelt County, where it again becomes indefinite, as this region of high plains is devoid of surface drainage fines. Beyond the region of high plateaus, which does not extend east of the one hundred and second meridian, the boundary is fairly well defined to the Gulf, lying paraUel to the Pecos at a distance of about 50 miles to the east, and below the mouth of the Pecos roughly paralleling the Rio Grande at an average distance of 30 miles.

In Mexico the boundary of the nominal drainage area coincides with the mountain ranges in the western part of the State of Chi-

House Doc. 959 ; 63d Cong., 2d Soss.

MAP OF RIO GRANDE DRAINAGE BASIN

Scale S,<)6&,666 vni*B

Hous* Doo. 9B9 ; 63d Cong., 2d Sesi.

GENEEAL FEATURES OF RIO GRANDE BASIN. 19

hiiahua. It turns eastward in the northern part of the State of Durango and takes a generally easterly course to the Gulf at the mouth of the Rio Grantle. As in the United States, however, the effective drainage area of the river is considerably reduced by the large nonproducmg areas.

TOPOGRAPHY.

The topographic features of the area drained by the Rio Grande range in variety from mountain peaks 14,000 feet and more in eleva- tion to the low plains bordering the Gulf. The most important area as regards water supply is the mountainous part of the Colorado section above San Luis Valley, where the Rio Grande and its tribu- taries flow through narrow valleys whose sides extend up to the crest of the Continental Divide. San Luis Valley is a high level plateau at an elevation ranging from 7,500 to 8,000 feet.

The New Mexico section of the basin is a high plateau region traversed from north to south by more or less parallel mountain ranges that form long, narrow vaUeys, some of which are completely inclosed. In this area elevations range from 13,000 feet in the moun- tains near Santa Fe to less than 4,000 feet in the valleys of the Rio Grande and Pecos.

Below El Paso, in the trans-Pecos region of Texas, there is a mountainous area that probably extends into the Mexican part of the basin and that, in Texas, attains altitudes of 7,000 to 8,000 feet. East and south of the trans-Pecos region the country gradually becomes smoother, passing from