Quality of Water 

Conchas Reservoir 

New Mexico 

1939-49

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1110-C

Quality of Water 

Conchas Reservoir 

New Mexico 

1939-49

By JOHN D. HEM

CONTRIBUTIONS TO HYDROLOGY, 1948-51 

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1110-C

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1952
UNITED STATES DEPARTMENT OF THE INTERIOR 

Oscar L. Chapman, Secretary

GEOLOGICAL SURVEY 

W. E. Wrather, Director

For sale by the Superintendent of Documents, U. S. Government Printing Office 

Washington 25, D. C. - Price 25 cents
CONTENTS

Past

Abstract_______.____._...__.._______________________ 83

Introduction...___________________________________________________ 83

History, scope, and purpose of the investigation.__________________ 83

Acknowledgments..___________________________________________ 84

Description of Canadian River basin_-_____________._________________ 85

Description of Conchas Dam______________________________________ 87

Tucumcari irrigation project________________________________________ 88

Previous investigations..___________________________________________ 90

Methods of collection and analysis of water samples_.___---_-_-_----._ 90

Location of sampling stations. __________________________________ 90

Analytical procedures._--_______________________--______--_---- 91

Collection and analysis of samples-______-_-___----_-_------- 91

Significance of specific conductance.-..---------------------- 92

Expression of results--_--_-_---___-______--____-_-__-----------_-_- 93

Chemical character of inflow._._________________.___.---___-__--__-- 93

Canadian River.__--___________________-____.___-__ ___--_-__- 94

Conchas River._______________________________________________ 98

Chemical character of stored water___________-_-___-__-___-----___ 99

Changes occurring during storage__________---__-_-__--__--_--_ 101

Piecipitation of calcium carbonate..---_________--____--._--_ 101

Evaporation._-__________-____________-___.---__.__-_.____ 103

Mixing of stored water-_-_--_-_-_____-_-__-__-___--__--------_- 103

Relation of quality of water to use_________________________________ 104

Irrigation_-____---_______________________-_____--____--_-_-_ 104

Domestic use.________________________________________________ 105

References cited.__________--_____-_-____-_______-___-_--_---.--___ 107

Analyses.-_-_-___-------_----____-_-___________________________ 107

ILLUSTRATIONS

Page 

PLATE 6. Aerial view northwest, main section of Conchas Dam__________ 94

FIGTJBE 11. Map of Canadian River drainage basin.___________________ 86

12. Map of Conchas Reservoir with water level at 4,201 feet___ 89

13. Specific conductance of composite water samples from Canadian River and the surface of Conchas Reservoir at station 2 

and monthly contents of reservoir, 1939-49_--_-_-------_ 95

14. Minimum and maximum annual weighted-average and individual analyses, Canadian River near Sanchez__________ 97

15. Typical analyses of low and high concentrations and variations

of quality with depth, Conchas Reservoir..________.___»_ 102

16. Diagram for use in interpreting the analysis of irrigation water. 106

m
3V CONTENTS

TABLES

Page 

TABLE 1. Quality of water of Canadian River near Conchas Dam site____ 108

2. Quality of inflow to Conchas Reservoir from Canadian River,

1939-49_----__--_-____ ________________________________ 110

3. Quality of inflow to Conchas Reservoir from Conchas River, 114

4. Quality of water in Conchas Reservoir at station 1, 1939-49-.-- 117

5. Quality of water in Conchas Reservoir at station 2, 1939-49__-_ 119

6. Quality of water in Conchas Reservoir at station 3, 1939-49- 122

7. Quality of water in Conchas Reservoir at station 6, 1941-49. __ 125

8. Quality of water in Conchas Reservoir at station 7, 1941-49- __ 126
QUALITY OF WATER OF CONCHAS RESERVOIR, N. MEX.,

1939-49

By JOHN D. HEM

ABSTRACT

Conchas Reservoir is formed by Conchas Dam which is located on the Canadian 

River in San Miguel County in northeastern New Mexico. Storage in the 

reservoir began in December 1938. At the level of the spillway in the main dam 

(pool elevation, 4,201 fset), the reservoir has a capacity of 370,000 acre-feet. 

Water from the reservoir is used on the Tucumcari Project of the Bureau of Reclamation. Construction of canals and laterals on the project, which contains 

about 45,000 acres, was completed in 1949.

Samples for chemical analysis were collected from Canadian and Conchas 

Rivers for a time in 1936 during construction of the dam. After storage began, 

samples of inflow and stored water were collected for chemical analysis from April 

1939 to July 1949. During the period of record, the water of Canadian River 

ranged in dissolved solids concentration from 133 parts per million September 

22, 28-29, 1941, to 2~32d parts per million July 10-11, 1943. Water stored in the 

reservoir ranged in dissolved solids from about 320 to about 800 parts per million 

after a volume of stored water cf 25,000 acre-feet was first attained. In general 

the predominant anion in the inflow and stored water is sulfate, but of the cations 

calcium, magnesium, and sodium all are present in significant amounts. At low 

concentrations the water in Canadian River is of the calcium bicarbonate type. 

Except during and for some time after periods of excessive inflow, the water in 

the reservoir is generally well mixed.

The water from Conchas Reservoir is classified as good to permissible in quality 

for irrigation, based on standards of the United States Department of Agriculture. 

The water is very hard and rather high in sulfate, but is otherwise satisfactory 

for domestic use. It is anticipated that with the Tucumcari Project in full 

operation, greater amounts of water will be used for irrigation in the years following 1949, and a wider range of fluctuation of the quality of stored water than that 

occurring in the last 6 years of the 1939-49 period, may be experienced.

INTRODUCTION 

HISTORY, SCOPE, AND PURPOSE OF THE INVESTIGATION

The studies upon which this report is based were begun in January 

1936 near the reservoir site early in the construction period. At that 

time samples were obtained from Canadian River at several points 

below its confluence with Conchas River during the first 3 months of 

the year and also in June and July. No further sampling was done 

until after storage began in the reservoir at the end of 1938.

Conchas Dam was built as a multiple-purpose project under the 

control of the Corps of Engineers. The quality-of-water studies were 

made to determine the suitability of the stored water for irrigation and

municipal uses.

83
84 CONTRIBUTIONS TO HYDROLOGY, 1948-51

Beginning in April 1939, water samples were collected systematically 

at various locations within the reservoir, and near the end of that 

year collection of daily samples of inflow from Canadian and Conchas 

Rivers was begun. Investigations also were begun late in 1939 to 

determine variations of chemical quality with depth below the water 

surface within the reservoir. By the middle of 1940, samples were 

being collected daily from Canadian River at or near the gaging station 

near Sanchez, and during periods of flow from Conchas River near the 

gaging station at Variadero. Surface samples were being collected 

weekly at three points in the reservoir near the dam, and sets of 

samples were being collected at 2- to 4-month intervals at different 

depths at these three points and after October 1941 at two other points 

in the reservoir farther upstream. This program of sampling was 

continued until the end of the investigation on June 30, 1949.

The quality-of-water studies at Conchas Reservoir provide information on the chemical characteristics of water available from the 

reservoir and assist in determining the effect of inflowing water at 

various reservoir stages. This report includes a summary of all 

previously published analyses and contains all the significant analyses 

made during the investigation which have not previously been 

published.

ACKNOWLEDGMENTS

The funds for the quality of water studies were provided by the 

Corps of Engineers, Department of the Army, and all routine samples 

were collected by employees of the Corps of Engineers. The investigation was made under the direction of S. K. Love, Chief, Quality of 

Water Branch, and was under the general supervision of C. S. Howard, 

Regional Chemist of the Geological Survey. The description of 

Conchas Dam included in this report is based on an information 

pamphlet issued by the Albuquerque District, Corps of Engineers, 

revised in March 1948. The description of the Tucumcari Irrigation 

Project is based on the Bureau of Reclamation descriptive statement, 

"The Tucumcari Project, New Mexico, June 1948." The author 

wishes to express his appreciation to John T. Martin of the Albuquerque District, Corps of Engineers and to Ray J. Lyman, U. S. Bureau of 

Reclamation, Tucumcari, N. Mex. for making available maps and 

additional information on Conchas Dam and the Tucumcari Irrigation 

Project, included in this report. The photograph of Conchas Dam 

used in preparing plate 6 was furnished by the Corps of Engineers.

Analyses were made in the laboratories of the Geological Survey at 

Washington, D. C,, Roswell, N. Mex., and Albuquerque, N. Mex., Jby 

V. E. Arnold, J. P. Bertino, W. W. Brannock, A. W, Carlson, T. 

Downer, W. I. Ettleman, I. M. Gutierrez, J. L. Hatchett, J. D. Hem, 

C. S. Howard, L. S. Hughes, R. T. Kiser, M. E. Krausnick, W. L.
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 85

Lamar, E. W. Lohr, W. L. Minton, W. M. Noble-, C. D. Orcutt, M. D. 

Reeves, H. R. Simms, S. A. Simpson, G. R. Stewart, N. Talvitie, H. B, 

Waha, Jr., W. F. White, and E. F. Williams.

DESCRIPTION OF CANADIAN RIVER BASIN

Canadian River rises in northern Coif ax County, N. Mex., west of 

Raton, flows generally south-southeastward to Conchas Dam in southeastern San Miguel County; thence it flows eastward across Quay 

County into Texas. The river and its tributaries drain an area of 

7,327 square miles above Conchas Dam. Except for a few square 

miles in Colorado near Raton, all the drainage area above the dam is 

in New Mexico, The entire basin of Canadian River above the New 

Mexico-Texas line is shown on the base map, figure 11.

The principal tributaries of the river above Conchas Dam rise in the 

Sangre de Cristo Mountains and in smaller ranges along the western 

edge of the basin. Among the more important tributaries from the 

west are Vermejo, Cimarron, and Mora Rivers, and Ocate Creek, all 

of which are perennial streams. Conchas River enters the reservoir 

from the west but rises in an area of comparatively low elevation and 

is intermittent. All tributaries of Canadian River from the east 

above the reservoir are small ephemeral or intermittent streams.

The maximum altitudes reached in the Sangre de Cristo range are 

more than 13,000 feet, but only a few peaks within the basin rise 

above 12,000 feet. Most of the area of the basin above Conchas Dam 

comprises plains and remnants of plains at various levels. The altitude of most of this part of the basin is from 4,200 to 7,000 feet. The 

altitude of the river bed at the dam is 4,050 feet.

The climate of the basin is characterized by abundant sunshine, low 

humidity, and considerable wind movement. Climatic conditions 

within the basin are influenced considerably by differences in altitude, 

with short cool summers and long periods of winter cold at the highest 

elevations, and long warm summers with only short periods of cold 

weather in winter in the lower plains area. In much of the mountain 

area annual precipitation averages more than 20 inches, a large part 

of which is received in the form of snow. The major tributaries of 

Canadian River receive much of their runoff from the slopes of the 

high mountains. Most of the precipitation on the plains area is 

received in the form of local summer thundershowers, some of which 

are violent and cause flash floods in normally dry stream channels. 

The mean annual precipitation at Tucumcari is 16.42 inches, which 

probably represents about the normal amount for the plains area of 

the basin. Evaporation from a Weather Bureau type of land pan at 

Conchas Dam averaged 98.29 inches annually for a 12-year period 

ending in 1949.
86 CONTRIBUTIONS TO HYDROLOGY, 1948-51

FIGURE 11. Map of Canadian River basin.

The principal cities of the Canadian River basin in New Mexico are 

Raton, (pop. 7,927), Tucumcari, (pop. 8,369), and Clayton, (pop. 

3,268). Of these cities only Raton is in that part of the basin above 

Conchas Dam, but Tucumcari is in the center of a large area irrigated 

with water from Conchas Reservoir.

The basin of Canadian River in New Mexico is crossed by several 

rail lines. Two lines of the Chicago, Rock Island, & Pacific R. R. 

join at Tucumcari and extend to the west as a part of the Southern
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 87

Pacific system. A branch of the Southern Pacific R. R. extends 

northeast from Tucumcari to Dawson. The Colorado and Southern 

Ry. crosses the northeastern corner of the basin at Clay ton. The 

Santa Fe Ry. main line crosses the western part of the area between 

Las Vegas, just outside the basin, and Raton and extends north into 

Colorado.

Several paved highway routes which are heavily traveled cross the 

edges of the basin. U. S. Highways 66 and 54 cross the southern 

edge of the basin through Tucumcari, and U. S. Highways 64 and 87 

cross the northern edge through Raton. U. S. Highway 85 parallels 

the Santa Fe Railroad between Las Vegas and Raton. Several State 

highways cross the interior of the basin. Parts of these routes are 

surfaced. The unimproved roads in the basin are very difficult to 

traverse in wet weather.

DESCRIPTION OF CONCHAS DAM

Conchas Dam is on Canadian River about one-eighth mile below its 

confluence with Conchas River, and about 35 miles northwest of 

Tucumcari, N. Mex. The construction project was approved by 

President Franklin D. Roosevelt as a part of the Works Relief Program, July 29, 1935, and was assigned to the Corps of Engineers, 

Department of the Army. Storage began December 29, 1938, 

although construction was not completed until September 15, 1939. 

The reservoir is intended to provide flood control, irrigation, and 

recreational benefits.

The main dam is a concrete gravity structure in the canyon of 

Canadian River (pi. 6), with a maximum height of 235 feet from the 

top of the roadway to the foundation and a crest length of 1,250 feet. 

The structure, which contains 755,000 yards of concrete, has outlets 

near its base to maintain low water flow and to drain the reservoir 

should it become necessary. There is a 340-foot ungated spillway 

section at the middle of the dam for passage of ordinary high-water 

flow. Wing dams extend north about 1,000 feet and south about 

4,000 feet from the main dam. These are of earth and rock-fill 

construction. A concrete emergency spillway with a crest length of 

3,000 feet is north of the dam; it is flanked by two earth and rockfill dikes with an aggregate length of about 2,550 feet. An additional 

dike across low ground is about a mile south of the main dam. This 

dike has a length of about 6,400 feet ard is constructed of earth and 

rock-fill. A small saddle dam about 3 miles south of the main dam is 

designed to serve as a "fuse plug" in event of extreme flood. The 

reservoir map (fig. 12) shows the locations of these structures.

Irrigation water is diverted from the reservoir through a tunnel 

under the south dike at an elevation of 4,155 feet. The crest of the 

spillway in the main dam is at an elevation of 4,201 feet. The crest

9T5952 52 2
88 CONTRIBUTIONS TO HYDROLOGY, 1948-51

of the emergency spillway is at an elevation of 4,218 feet. When the 

water is at the 4,155-foot level, the reservoir contains 90,800 acre-feet 

of water. When filled to the 4,201-foot level, the reservoir contains 

370,000 acre-feet of water. The lake has a surface area of 9,707 acresat this elevatiqn and extends 14 miles up the Canadian River valley 

and 11 miles up the Conchas River valley. The map of the reservoir 

area (fig. 12) shows the extent of the reservoir with the water at the 

4,201-foot level. At the 'elevation of the emergency spillway, 4,218 

feet, there is a storage capacity of 566,000 acre-feet. The reservoir 

storage figures are taken from the area-capacity table based on the 

1949 resurvey of the reservoir.

The level of 4,155 feet is the lowest point to which it is anticipated 

the reservoir will be drawn down, and the permanent pool below this 

elevation is used primarily for sediment storage and for recreational 

purposes. The capacity between elevations 4,155 and 4,201 feet 

constitutes irrigation storage and amounts to 279,200 acre-feet. The 

portion of the reservoir between elevations 4,201 and 4,218 feet is to 

be used for detention storage for flood control. A 150-kw. hydroelectric generator has been installed in the main dam, and the dam was 

so constructed that larger generating units could be installed if use of 

the water for this purpose is ever required. An area near the dam has 

been set aside and partly developed as Conchas State Park, to enhance 

the recreational use of the reservoir.

TUCUMCARI IRRIGATION PROJECT

The Tucumcari Irrigation Project was authorized by Congress in 

1938. Water for the project is stored in Conchas Reservoir. The 

Arch Hurley Conservancy District, organized under the laws of New 

Mexico, comprises the lands in the vicinity of Tucumcari irrigated with 

this water. Construction of the irrigation system was begun in 1940 

but was suspended in December 1942 because of the war emergency. 

In 1944 the project was reauthorized as an emergency food project, 

and late in 1945 water was made available to 7,000 acres of project 

land. The construction of canals and laterals was completed in 1949. 

The distribution system includes about 116 miles of main canal and 

about 200 miles of laterals and serves about 45,000 acres of irrigable 

lands. The mam canals have 35 siphons, with an aggregate total 

length of more than 28,000 feet, and 5 tunnels, with an aggregate total 

length of more than 30,000 feet. These structures were necessitated 

by the rough terrain through which the canals pass between Conchas 

Dam and the areas to be irrigated.

Crops grown successfully under irrigation at Tucumcari include 

alfalfa, cotton, small grains, corn and various forage crops, and vegetables. Farmers in the project area are experimenting with various
Stotlon 5 on Conchoi River ot Quintono 

Ronch, II milet obovt heod of reservoir

FIGTJKE 12. Map of Conchas Reservoir with water level 
90 CONTRIBUTIONS TO HYDROLOGY, 1948-51

crops. Because of the newness of irrigation in the area, it is not 

now known which crops will eventually be most important.

PREVIOUS INVESTIGATIONS

Chemical analyses of water samples collected from the Conchas 

Reservoir and Canadian and Conchas Rivers after September 30, 

1950, have been published or are to be published in Water-Supply 

Papers, by the Quality of Water Branch of the United States Geological Survey, for the years 1941-49. Each of the annual reports from 

1946 to 1949 will also contain analyses for the Canadian River and 

its tributaries in the upper part of the basin in Colfax County.

Chemical analyses of samples collected near the mouth of Sapello 

Creek a tributary of Mora River at Los Alamos Post Office for 

the period March 1905 to April 1906 have been published. (Stabler, 

1911, pp. 120-122.) It is not known to what extent conditions in 

the basin may have changed since these samples were collected. 

Therefore, the analyses may not be representative of present conditions. A few other analyses for surface waters in the basin above 

Conchas Dam have been published. (Griggs, 1948, pp. 172-174.)

Some data on quality of ground waters in Colfax County have been 

published, and a similar publication is in preparation for San Miguel 

County. (Griggs, 1948, pp. 159-171, 175-176.) Chemical analyses 

for a number of wells, springs, and surface sources in the Tucumcari 

Irrigation Project area are contained in an unpublished report. (Hem 

and Hughes, 1948.) No data on quality of surface or ground waters 

are available for most of the basin outside these two counties and the 

Tucumcari Project area.

METHODS OF COLLECTION AND ANALYSIS OF 

WATER SAMPLES

LOCATION OF SAMPLING STATIONS

The first samples collected from Canadian River in this area were 

obtained in January 1936 near the site of Conchas Dam short distances above and below the mouth of Conchas River. Sampling "was 

discontinued later in that year. Beginning in November 1939, daily 

samples were obtained from Canadian River from flowing water 

immediately above the reservoir, 8 to 10 miles downstream from the 

gaging station. In February 1941 the sampling station was moved 

upstream to the bridge on State Highway 65 (locally known as Garms 

Bridge) which is the site of the gaging station. In February 1942 

the sampling station was moved farther upstream to Sabinoso, 5 

miles above the gaging station, where it remained until the end of the 

study. Samples collected at these various points were believed to 

be comparable and representative of water passing the gaging station 

and entering the reservoir. Although several small tributaries enter
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 91

the river between Sabinoso and the head of the reservoir, they are 

all ephemeral.

In 1936, a few samples were collected from Conchas River at its 

mouth, and beginning in November 1939 samples were obtained from 

flows in Conchas River immediately above the reservoir, some 7 or 

8 miles below the gaging station at Variadero. Samples were collected at the gaging station from March 1941 to April 1942, and subsequently at Quintana Ranch 4 miles upstream from the gaging 

station. Quality of water records for Conchas River are fragmentary.

The locations of five regular sampling points within the reservoir 

are shown on the reservoir area map, figure 12. Station 1 is described 

as being hi the former channel of the Conchas River, 3,500 feet above 

Conchas Dam. Station 2 is below the confluence of Conchas and 

Canadian Rivers, at the upstream face of Conchas Dam. Station 3 

is in the former Canadian River channel, 1,300 feet above the dam. 

These three stations are in the downstream end of the lake, and samples were first taken at these, points in April 1939. Station 6 is in the 

Conchas River arm of the reservoir, 5 miles above the dam, and 

station 7 is in the Canadian River arm, 5 miles above the dam. Sampling at stations 6 and 7 was begun in October 1941. Samples of 

water were collected at the reservoir surface each week at stations 

1, 2, and 3, and sets of samples at different depths from the surface to 

the bottom of the reservoir were taken two to five times a year at 

each of the five stations. A few samples were collected during the 

study at other locations in the reservoir.

For the investigation the station on Canadian River above the 

reservoir was called station 4 and the station on Conchas River above 

the reservoir was called station 5. These stations have been described previously. Their locations are shown on figure 11 and the 

position of stations 4 and 5 with respect to the other reservoir stations is indicated on figure 12.

ANALYTICAL PROCEDURES

COLLECTION AND ANALYSTS OF SAMPLES

Specific conductance was determined for each sample collected. 

Daily samples of inflow to the reservoir were combined into composite 

samples for analysis. Generally the samples for a month from Canadian River were combined into three composites, one for the period 

from the first to the tenth of the month, the second for the eleventh 

to the twentieth, and the third for the remaining days of the month. 

When the daily conductance values showed excessive day-to-day 

variation, the composites were made for shorter periods, so that only 

daily samples of similar conductance were included in any composite 

sample. Samples collected from Conchas River were sometimes 

made into composite samples covering periods longer than 10 days.
92 CONTRIBUTIONS TO HYDROLOGY, 1948-51

Samples collected weekly at the surface in the reservoir were combined into composites each covering a month. Sets of samples collected at vari6us depths were not composited.

Analyses of the composite samples from Canadian River near 

Sanchez generally included determinations of specific conductance, 

pH, silica, iron, calcium, magnesium, bicarbonate, sulfate, chloride, 

fluoride, nitrate, and boron. From these data sodium plus potassium, 

total and noncarbonate hardness, and percent sodium were calculated. 

During the 1947 water year, however, only a few determinations were 

made on composite samples from this station. Composite samples 

from Conchas River were usually analyzed for only a few constituents. 

Composites of reservoir water often were analyzed for only a few 

constituents because of the nearly constant composition of the reservoir water. Generally, for one or more of the samples in each set 

taken from several depths, determinations were made of conductance, 

calcium, magnesium, bicarbonate, sulfate, chloride, and nitrate. 

For each of the remaining samples in the set only two or three constituents were determined.

Analytical procedures were those commonly used by the Geological 

Survey. (Collins, 1928, pp. 235:261; Amer. Pub. Health Assoc. 

1946, pp. 1-112.)

SIGNIFICANCE OF SPECIFIC CONDUCTANCE

The specific conductance of a water is a measure of its ability to 

conduct an electric current. Conductance, the reciprocal of resistance, 

is expressed in reciprocal ohms, or mhos, but since the mho is an inconveniently large unit to use in studies of natural waters, millionths 

of mhos or micromhos are commonly used in reporting the specific 

conductance of natural waters. In the records of quality of waters 

in the United States that were obtained by the Geological Survey prior 

to October 1, 1947, conductance values are expressed as K x 10s at 

25 C. These values may be converted to micromhos by multiplying 

them by a factor of 10.

The conductance of a water in general varies with the concentration 

of dissolved solids and is usually higher for more concentrated waters, 

but there is no direct proportional relationship between conductance 

and dissolved solids that applies to all natural waters. This is true 

because dissolved minerals affect the conductance differently. For 

waters such as those entering or stored in Conchas Reservoir, however, 

a fairly consistent relationship exists between dissolved solids concentrations and conductance. For water in the Conchas Reservoir area 

specific conductance in micromhos multiplied by 0.7 gives approximate dissolved solids in parts per million.
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 93

EXPRESSION OF RESULTS

Table 1 contains previously unpublished analyses of samples collected between January 8 and July 19, 1936. Table 2 contains previously unpublished analyses of samples collected between November 

11, 1939, and October 1,1940, and a summary of analyses for Canadian 

River for water years 1941-49. For each of the 9 water years beginning with 1941 the analyses of the composite samples having maximum 

and minimum dissolved solids are given, and the annual weighted-, 

average analysis is given for each year except 1942 and 1949. Table 

3 contains data for Conchas River above the reservoir, but no weighted 

averages are shown for this station as none could be computed on the 

basis of available fragmentary records. Previously unpublished 

analyses for the period from April 1939 to September 1940 and two or 

three typical analyses of reservoir water for each water year from 1941 

to 1949 are shown in tables 4, 5, and 6. Tables 4 to 8 contain typical 

analyses showing variations in quality with depth at each sampling 

point in the reservoir. One set of observations is given for each water 

year for which such data are available.

Fluctuations in concentration of dissolved solids in Canadian River 

inflow and in stored water for one station during the period are shown 

graphically in figure 13. Chemical character of inflow and stored 

water are shown graphically in figures 14 and 15.

Weighted-average analyses were computed by multiplying the discharge for the period of such composite sample by the quantities of 

the individual contstituents for the corresponding period and dividing 

the sum of the products for each constituent by the sum of the discharges. The weighted-average analysis represents approximately 

the composition of the water that passed the sampling station during 

the year had all the water been retained in a reservoir and thoroughly

mixed.

CHEMICAL CHARACTER OF INFLOW

Records of stream- flow show that the water stored in Conchas 

Reservoir comes largely from the Canadian River. From the time 

storage began in the reservoir until the end of the 1948 water year the 

total annual discharge of Conchas River into the reservoir ranged 

from 86,000 acre-feet during water year 1941 to 1,990 acre-feet during 

water year 1945. During 6 years of the period 1939 to 1948 the Conchas River discharge was 5 percent, or less, of that of Canadian River 

into the reservoir. During this same period, the annual discharge of 

Conchas River never was more than about 14 percent of the discharge 

of Canadian River for the same year. Therefore, although few complete analyses are available for Conchas River, the data which are 

lacking are of little practical importance. Inflow from small streams 

directly tributary to the reservoir probably is even less than inflow 

from the Conchas River.
94 CONTRIBUTIONS TO HYDROLOGY, 1948-51

CANADIAN RIVER

The water of Canadian River above the reservoir fluctuates widely 

and rapidly in dissolved solids concentration. This fact is strikingly 

illustrated in figure 13, where the specific conductances of composite 

samples are plotted against time for the period of record. Had daily 

conductance values been used in this illustration, even greater fluctuations would be shown. Rapid fluctuation in the concentration of 

dissolved solids is characteristic of. many streams in the southwestern 

United States (Hem, 1948, pp. 80-83), and Canadian River above 

Conchas Reservoir shows fluctuations similar in some respects to 

those of Pecos River and the Rio Grande. The fluctuations are 

related to such factors as the geology of the drainage basin, the nature 

of rainfall and runoff in the basin, and the manner in which water is 

diverted from or returned to the stream. Large areas of sedimentary 

rock are exposed in the lower parts of the basin above Conchas Dam. 

Some of these sedimentary rocks, and soils derived from them, contain 

soluble salts which are carried into the river by surface runoff and 

ground-water inflows. These rocks are the primary source of soluble 

matter in Canadian River both at high and low stages.

Waters containing less than 200 parts per million of dissolved solids 

occur in tributaries rising in the mountains at the west side of the 

basin. However, these waters are extensively used for irrigation, and 

the return flow from irrigated tracts carries increased concentrations 

of dissolved solids. Low flow in Canadian River near Sanchez commonly contains more than 1,000 parts per million of dissolved solids, 

and concentrations sometimes exceed 2,000 parts per million.

When rainstorms occur in those areas of the basin where soluble 

salts are exposed at the surface, the resulting runoff may contain 

considerable amounts of dissolved matter. Rises occurring after prolonged low-flow periods also have a flushing effect in the main river 

channel, dissolving soluble salts left by evaporation and flushing pools 

of stagnant highly mineralized water. As a result, the first water of 

such a rise to reach the gaging station may be as high as or higher than 

preceeding low flow in dissolved solids. The highest dissolved-solids 

concentration for the period of record was 2,320 parts per million; it 

occurred in water of a small rise on June 10 and 11, 1943, following 

about a week of moderately low flow. A rise occurred in Canadian 

River at Taylor Springs and near Roy, upstream from Sanchez, at 

this time, but none was observed in any of the tributaries from the west 

on which gaging stations were in operation.

The lowest concentrations of dissolved solids are observed during 

major flood periods, generally some time after the beginning of high 

flow. A series of high flows occurred in Canadian River basin late in 

September 1941 as a result of widespread and heavy rainfall in the basin
GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1110 PLATE 6

AERIAL VIEW NORTHWEST, MAIN SECTION OF CONCHAS DAM, SEPTEMBER 2, 1911 

Photograph furnished by Corps of Engineers, Albuquerque district

QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 95

during the last 2 weeks of the month. The first important rise of the 

period at Sanchez occurred on September 21, and the specific conductance of the sample collected that day was 447. The peak flow 

was reached the next day, September 22, and the sample collected that 

afternoon had a conductance of 213. Conductance values increased 

as the stage receded on subsequent days. A second large rise occurred 

on September 28 whan a conductance of 294 was obtained, and on the

» 200

FIGURE 13. Specific conductance of composite water samples from Canadian River near Sanchez, N. 

Mex., and the surface of Conchas Reservoir at station 2 (upstream face of dam), and monthly contents of 

reservoir, 193»-49.

following day, during a higher stage, the conductance was 203. The 

lowest concentration of dissolved solids for a composite sample at this 

station during the period of record was 133 parts per million (specific 

conductance 241) for the 3 days September 22, 28, and 29. This 

dissolved solids value, however, does not include silica, which was 

not determined for the sample.

The chemical character of the water of Canadian River entering the 

reservoir is shown in figure 14. The diagrams were prepared according:

975952 52-
96 CONTRIBUTIONS TO HYDROLOGY, 1948-51

to the system developed by Collins (1923, p. 394). Maximum and 

minimum annual weighted-average analyses for the period of record 

are shown, as well as maximum and minimum analyses of composite 

samples for the period of record.

Sulfate is normally the principal anion in the water of Canadian 

River at the Sanchez station, and there is a lesser amount of bicarbonate and a relatively small amount of chloride. Calcium, magnesium and sodium are present in important quantities, and usually 

no single cation predominates. At low concentrations, however, the 

water is of the calcium bicarbonate type.

The diagrams in figure 14 show that the maximum annual weightedaverage analysis has more than twice the concentration of dissolved 

solids of the minimum weighted-average. During the same period, 

the composite sample of maximum concentration is about 17 times as 

high in concentration of dissolved solids as the composite sample of 

minimum concentration!. These relationships show the variations in 

chemical quality typical of the stream, and also they show that important variations occur in the annual average concentration.

The minimum annual weighted-average concentration for Canadian 

River water for the period was probably that reported for the 1941 

water year. The runoff in the 1941 water year was 656,500 acre-feet 

as compared with 949,500 acre-feet in the 1942 water year. Because 

of lack of data for high flow in April 1942 and for several low-flow 

periods in 1941 and 1942, it is not possible to compute an accurate 

weighted-average analysis for the 1942 water year. The data available 

indicate that the minimum annual weighted-average concentration 

almost certainly could not have occurred in 1942, even though the 

annual runoff at the sampling point that year was the highest in the 

period of record. A tentative weighted average not included in 

table 2 computed for the period for which adequate samples were 

available in the 1942 water year, and which represents about 67 

percent of the total discharge for the year, shows an average concentration of 515 parts per million of dissolved solids. If all the unsampled water had a concentration of dissolved solids equal to the 

minimum observed for the year at high flow in September, the weighted 

average for the dissolved solids would have been about 440 parts per 

million. This tentative value may be compared with the weighted 

average of 368 parts per million for the dissolved solids that was 

computed on the basis of practically complete data for the year ended 

September 30, 1941 (see table 2). Actually, the concentration of 

dissolved solids during the periods in 1942 when no samples were 

taken probably would have averaged considerably above the recorded 

minimum for the year because the river was at moderately low stages 

for a considerable part of the time when no samples were taken. 

Probably the weighted-average concentration of dissolved solids for
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 97

5 Conchas River, August 

4,19-30, 1946

24

20

1 Annual weighted average, 

Canadian River 1941

2 Annual weighted average, 

Canadian River 1943

3 Minimum concentration, Canadian 

River September 22,28-29,1941

4 Maximum concentration, Canadian 

River June 10-11, 1943

FIGURE 14. Minimum and maximum annual weighted-average and individual analyses, Canadian 

River near Sanchez, N. Mex., and analyses of low and high concentration, Conchas River at 

Variadero, N. Mex., 1939-49.
98 CONTRIBUTIONS TO HYDROLOGY, 1948-51

the year ending September 30, 1942, would have been somewhere 

between 515 and 440 parts per million had an adequate number of 

samples been collected throughout the year.

The fact that the years of maximum total flow are not necessarily 

the years of the minimum average concentration of dissolved solids 

and vice versa has been observed in studies of other streams in New 

Mexico. Rocks exposed in the drainage basin of streams of the 

State may differ widely from place to place in their soluble mineral 

content. Hence, certain streams may contain comparatively high 

concentrations of soluble matter when carrying flood waters which 

originate in those parts of the drainage basin where exposed rock 

formations contain large amounts of soluble mineral matter. For 

such streams the distribution of precipitation in the basin and the 

spacing of flood flows with respect to time during the year are perhaps 

more important in producing runoff with low concentrations of dissolved solids than is high total annual runoff.

The fact that the maximum annual weighted-average concentration 

occurred in the 1943 water year is also of interest, because the flow in 

that year was greater than that in the succeeding 4 years for which 

records are available and was actually fourth highest for the period of 

record. (See table 2.) It is possible that the high-average dissolved 

solids (993 parts per million) for the 1943 water year was partly the 

result of increased ground-water runoff, which would have maintained 

an unusually large base flow of rather highly mineralized water in the 

river. This increase in ground-water runoff would be expected to 

follow the two abnormally wet years of 1941 and 1942. Definite proof 

of an increase in ground-water runoff is lacking, but discharge records 

for the station indicate a probable high base flow in 1942 and 1943. 

The high weighted-average concentration of dissolved solids in the 

1943 water year may also have been the result of unusually low spring 

runoff. Under these conditions a subnormal quantity of dilute water 

would pass the station and would tend to increase the weigh ted-average 

concentration for the year.

CONCHAS RIVER

Conchas River carries no flow at the sampling point near the 

Variadero gaging station except during and shortly after storm 

periods. A rather small number of analyses are available for this 

stream, and most of these are not complete enough to show the 

chemical character of the water. Two analyses are shown diagrammatically in figure 14 to illustrate the chemical character of water of 

different concentrations. Data available are not complete enough to 

permit diagramming of maximum and minimum concentrations for 

the period of record on this stream.
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 99

CHEMICAL CHARACTER OF STORED WATER

Figure 13 provides a comparison of the fluctuation of dissolved 

solids of Canadian River with changes in concentration of the water 

in storage as sampled at the surface of the reservoir at station 2 (see 

fig. 12). Specific conductances of monthly composites of the surface 

samples from the reservoir are plotted in figure 13. Had conductances 

of individual weekly samples been used, however, only slightly greater 

fluctuations would be shown. In general, the illustration shows that 

the water at the surface of the reservoir at the dam maintains a 

remarkably constant concentration, even though there are wide" and 

rapid fluctuations in quality of inflow and although the inflow was not 

completely mixed with stored water during high-flow periods. Even 

the rather large year-to-year variation in weighted-average concentration that characterizes the inflow from Canadian River does not 

cause variations of equal magnitude in the reservoir water. Most of 

the changes took place in the first 2 years of record, when the reservoir 

was being filled for the first time.

Figure 13 also shows the quantity of water in storage in the reservoir 

at the end of each month from 1939 to 1949. Storage began near the 

end of December 1938, but the reservoir contents did not reach 

100,000 acre-feet until late in the summer of 1940. During the 

period of filling to this level, the small volume of water held in the 

reservoir was considerably affected by quality of inflow. The first 

samples were collected from the reservoir on April 8, 1939, when only 

about 15,000 acre-feet of water was in storage. The concentration 

of dissolved solids in the sample taken at station 3 (869 parts per 

million) was the highest of record for stored water at the surface of 

Conchas Reservoir, and it represented accumulated winter low flow. 

As the spring and summer runoff was added to the stored water, its 

concentration of dissolved solids decreased. However, from the 

fall o£ 1939 until early in the spring of 1941, inflow to the reservoir 

was small in volume. The runoff of Canadian River at Sanchez in 

the 1940 water year (34,210 acre-feet), was the lowest total annual 

runoff of any of the years covered in this report. From the fall of 

1939 until the spring of 1941, the concentration of reservoir water 

gradually increased. In March, April and May of 1941 inflow was 

sufficient to fill the reservoir to the level of the spillway and water 

was spilled in large quantities during 1941 and 1942.

The minimum conductance of stored water at the dam for the 

period of record was observed in October of 1941 when several samples 

collected from the surface at station 2 had conductances of 454 to 456 

micromhos. Mixing of inflow with stored water, however, probably 

was incomplete during this period. The concentration of the stored 

water increased slowly from October 1941 through most of 1942. It 

increased for the subsequent years to a conductance of 1,150 micro-
100 CONTRIBUTIONS TO HYDROLOGY, 1948-51

mhos in mid-1946 which was the peakfortheperiodsincestorage volume 

first exceeded 25,000 acre-feet in 1939. The concentration decreased 

late in 1946, then fluctuated in a narrow range near conductivity 1,000 

to the end of the period of record. Figure 15 shows diagrammatically 

the analyses for reservoir water of near-maximum concentration in 

1945 and near the minimum in 1941. Analyses of stored water are 

included in tables 4 to 8.

Probably the principal reason for the effectiveness of Conchas 

Reservoir in maintaining the water in storage at so nearly a constant 

concentration during the period of record was the large volume of 

water held in storage. At all times after initial filling, in 1941 the 

amount of water in storage was large compared to the amount that 

entered during a single flood. Any such flood, therefore, when mixed 

with the water in storage could have only a minor effect on the concentration of dissolved solids of the water.

It may be anticipated that water stored in Conchas Reservoir will 

continue to have a comparatively minor fluctuation in concentration of 

dissolved matter, although fluctuations greater than those that 

occurred between 1944 and 1949 may be expected. The reservoir 

will probably be operated so as to maintain a pool of 100,000 acre-feet 

or more, primarily for recreational purposes. This water, held 

back from year to year, will mix with the inflow and tend to minimize 

changes in the quality of stored water, unless the inflow is very great 

as it was in 1941. So long as a permanent pool of this size is maintained, however, it is unlikely that minimum concentrations of reservoir water will drop much below those observed in 1941. While the 

permanent pool is maintained the reservoir can never be completely 

filled with flood waters of minimum dissolved solids concentration. 

The gradual filling of the permanent pool with sediment will eventually 

decrease the size and the effectiveness of the pool in minimizing 

fluctuations in dissolved solids concentration of stored water.

As previously noted, the facilities for delivery of irrigation water to 

the entire Tucumcari Project area were not complete at the time this 

investigation was closed. Consequently, during the period of record, 

considerably less water for irrigation was withdrawn annually from 

the reservoir than may be normally expected in the future. Larger 

withdrawals for this purpose will tend to draw down the reservoir 

more nearly to the level of the irrigation outlet at the top of the 

permanent pool each summer and will probably result in a smaller 

average quantity of water in storage than during the period of record 

since 1941. Years of high discharge such as 1941 and 1942 also are 

likely to occur infrequently. A smaller volume of water available in 

the reservoir to mix with inflow will result in more" fluctuation of the 

dissolved solids concentration of stored water than occurred in most 

of the period of record. A succession of dry years, resulting in the
QUALITY OP WATER, CONCHAS RESERVOIR, N. MEX. 101

maintenance of little more than the permanent pool in storage might 

raise the concentration of the dissolved solids in the stored water to a 

maximum considerably above that observed during the period of 

record. Evaporation from the lake has an important effect, and 

losses from this source may at times exceed the inflow to the reservoir. 

Evaporation tends to increase the concentration of dissolved matter 

in the remaining water and would play an important part ia increasing 

the concentration of dissolved solids in the stored water during long 

dry periods.

In order to regulate the releases from the reservoir so as to maintain 

the stored water at the best possible quality, a continuing study of the 

chemical quality of the stored water is desirable. This study is 

especially needed if proposed municipal use of the stored water 

materializes.

Figure 15 shows the approximate variation of chemical character of 

stored water, based on analyses for the water of low concentration in 

storage in September 1941 and the water of considerably higher concentration in storage in July 1945. These analyses represent water 

at the surface at the upstream face of the dam (sampling station 2). 

It is recognized that somewhat higher concentrations were reached at 

this point in 1946, but none of the samples collected that year were 

analyzed completely enough to permit the preparation of a diagram. 

It is also recognized that at times the water at the surface of the 

reservoir at this sampling point might not have been representative 

of all the water stored in the reservoir. The data in figures 14 and 15 

show that water in storage is very similar in chemical character to the 

weighted-average analyses for Canadian River water. During the 

peraed of record the concentration of dissolved solids in stored water, 

however, has never reached as high a level as the maximum annual 

weighted average shown in figure 14.

CHANGES OCCURRING DURING STORAGE 

PRECIPITATION OF CALCIUM CARBONATE

The analyses for samples collected from water in storage show that 

water at the surface of the reservoir generally has a lower concentration of bicarbonate than that of the inflow from Canadian River which 

contributed to the stored water. This apparent difference in bicarbonate concentration probably is the result of precipitation of calcium 

carbonate from the water during storage. The effect has been 

observed in other reservoirs (Howard, C. S., personal communication) 

as well. The available analyses for reservoir water are very incomplete, and for a part of the period of record, at least, the water in 

storage was poorly mixed. It is not possible, therefore, with the data 

available to make any quantitive estimate of the effect of precipitation 

of calcium carbonate in Conchas Reservoir.
102 CONTRIBUTIONS TO HYDROLOGY, 1948-51

12

1 Conchas Reservoir station 2, surface. 

September 10, 1941

2 Conchas Reservoir station 2, surface, 

July 14, 1945

3 Conchas Reservoir station 7, surface, 

June 3,1943

4 Conchas Reservoir station 7, depth 

50 feet, June 3, 1943

5 Conchas Reservoir station 7, depth 

109 feet, June 3, 1943

6 Conchas Reservoir station 7, depth 

119 feet (bottom), June 3, 1943

No»K CI*N03

S04

HCOs

FIGUKE 15. Typical analyses of low and high concentrations and analyses of samples from different depths,

Conchas Reservoir, N. Mex.
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 103 

EVAPORATION

The fact that evaporation measured in a land pan at Conchas Dam 

averages more than 8 feet a year has already been cited. This high 

evaporation rate indicates that there may be a considerable increase 

in concentration of dissolved matter in stored water resulting from 

loss of water to the atmosphere. Attempts to evaluate the effect 

closely, however, have encountered difficulties. The records of water 

released from the reservoir are incomplete and it is uncertain what the 

quality of the spilled water was. Furthermore, available analyses 

for stored water may not represent satisfactorily the average composition of all water in the reservoir. Tentative computations, which 

are subject to these inaccuracies, show that at the end of the 1940 

water year the water in storage was about 5 percent higher in dissolved 

solids than it should have been as computed from data on quantity 

and quality of inflow. This difference probably was the result of

evaporation.

MIXING OF STORED WATER

The analyses in tables 4, 5, 6, 7, and 8 give indications of the extent 

to which the water entering the reservoir mixes with that already in 

storage. In many reservoirs it has been found that mixing is far 

from complete at times, and that flows of water may pass through a 

reservoir and be discharged without appreciable changes in their 

chemical composition even thought a large volume of water is in 

storage. The irregular shape of Conchas Reservoir and the variable 

quality of inflowing water might be expected to be factors contributing 

to poor mixing and to lack of uniformity of the quality of stored water 

in the two main arms of the lake.

Data collected during the study show no significant consistent 

difference in water samples collected on the same day at the surface 

of the reservoir at stations 1, 2, and 3. However, these sampling 

points are near the dam and at a maximum distance from points of 

inflow, so that the mixing effect should be most complete in that part 

of the reservoir. Surface samples taken on the same day at stations 

6 (Conchas arm) and 7 (Canadian arm) both of which are 5 miles 

above the dam, sometimes differed appreciably during the years of 

high flow in the first part of the study. From 1944 to the end of the 

investigation, however, sets of samples taken on the same day at all 

five points in the reservoir show practically uniform composition of 

water at the surface.

The samples taken at various depths show a lack of complete 

mixing at stations 1, 2, and 3 on several occasions, notably in February 

1942 and December 1942. The analyses for these periods show water 

of comparatively low concentration of dissolved solids overlying more 

concentrated water. Probably during periods of high inflow to the 

reservoir in 1941 and 1942, considerable amounts of water compara975952 52 4
104 CONTRIBUTIONS TO HYDROLOGY, 1948-51

tively low in dissolved solids spread over more highly mineralized 

water already in storage and passed down the reservoir to the dam 

without gaining appreciably in concentration. The time of sampling 

at stations 6 and 7 during 1941 and 1942 does not coincide exactly 

with that at stations 1, 2, and 3, but the results show lack of mixing 

at depth at least part of the time during those years. The available 

data do not show definitely that individual flows of water pass through 

the repervoir at depth without mixing, however, it is possible that such 

flows may occur at times.

Abnormally high concentrations of bicarbonate were noted in 

several samples of water collected at the surface of the sediment 

layer, or of water in the upper part of the sediment layer in the bottom 

of the reservoir. These abnormally high bicarbonate concentrations 

sometimes were associated with below-normal sulfate concentrations, 

as shown in figure 15, where results of analyses of a set of depth 

samples collected at station 7 are shown diagrammatically.

RELATION OF QUALITY OF WATER TO USE 

IRRIGATION

The principal future use of water from Conchas Reservoir probably 

will be for irrigation in the Tucumcari Project area. For satisfactory 

results, water to be used for irrigation should be free from excessive 

quantities of dissolved solids. However, the quality of water in the 

root zone of the irrigated plants is the controlling factor, and this is 

influenced by various conditions other than the quality of the irrigation supply. Among these conditions are the nature of the soil, 

effectiveness of drainage, amount of water applied, and amount of 

rainfall. In addition, crop plants differ considerably in their tolerance 

of salinity.

The water applied to a field in. the process of irrigation invariably 

contains some dissolved mineral matter. The evaporation from the 

land surface and the transpiration of the plants dispose of what essentially may be considered distilled water. The dissolved matter 

originally contained in this water is left behind. Some of this material 

is utilized by the plants in their structure, but a large part is not usable 

and is left behind either in residual water or in the soil. As a result 

the water in the root zone commonly has a higher content of dissolved 

solids than the original irrigation water. In order to keep the water 

of the root zone within acceptable limits of salinity, it is necessary 

occasionally to apply an excess of irrigation water. A part of this 

excess passes downward through the root zone to the water, table, 

carrying with it soluble matter which may have accumulated in the 

soil and root zone. This leaching may be accomplished also by heavy 

rainfall. However, leaching can be effective only if the drainage is 

sufficiently complete to keep ground water levels from rising exces-
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 105

sively. Where the water table is very near the surface the continuous 

evaporation of water from the moist surface soil causes the visible 

accumulation of soluble salts commonly called "alkali."

Another factor of considerable importance in the evaluation of 

irrigation water is sodium percentage. The percent sodium of a water 

is the proportion of sodium to the total cations calcium, magnesium, 

sodium, and potassium. Waters with excessively high sodium percentages may enter into a base-exchange reaction with the soils which 

they irrigate. As a result of this reaction, the soil is deflocculated 

and hardened and becomes progressively less permeable to water. 

This reaction is not stopped by adding excess water but may often be 

controlled by adding substances like gypsum to the soil.

The diagram in figure 16 has been adapted from that of Wilcox 

(1948, p. 26) and can be used as an aid in the evaluation of an irrigation water by plotting conductance against sodium percentage and 

noting the area on the diagram in which the resulting point falls.

The presence of boron in irrigation water in concentrations toxic to 

certain boron-sensitive plants constitutes a further problem in some 

areas. No boron concentrations sufficient to cause damage, however, 

were found in analyzing any surface water from this area.

On the whole the water stored in Conchas Reservoir was "good to 

permissible'' for irrigation most of the time from 1939 to 1949. For 

a time in 1941 and 1942 it was "excellent to good." Little difficulty 

should be experienced in using this water on well-drained land. The 

sodium percentage of the stored water appears to be less than 40 at 

all times.

By wiy of contrast, the inflow to the reservoir from Canadian 

River, during the investigation, ranged from "excellent to good" to

"unsuitable."

DOMESTIC USE

Standards for drinking water supplied in common carriers have 

been published by the U. S. Public Health Service (1946, pp. 371-384). 

According to these standards a satisfactory drinking water should 

contain no more than 1 4 5 parts per million of fluoride and preferably 

no more than 250 parts per million of chloride or sulfate, 125 parts 

per million of magnesium, or 500 parts per million of dissolved solids. 

However, concentrations of dissolved solids as much as 1,000 parts 

per million may be permitted if better water is not available. These 

standards are commonly used for evaluation of drinking water, but 

it is recognized that waters of higher concentration are used continuously by many people without apparent ill effects. During the period 

of record, the water of Conchas Reservoir always contained less than 

1,000 parts per million of dissolved solids, but for a considerable 

part of the time the sulfate concentration was more than 250 parts per 

million. Fluoride concentrations in the stored water appear to be low.
CONTRIBUTIONS TO HYDROLOGY, 1948-51

500 1,000 1,500 2,000 2,500 3,000 

TOTAL CONCENTRATION AS ELECTRICAL CONDUCTIVITY

(MICROMHOS) 

FIGURE 16. Diagram for use in interpreting the analysis of krigation water.

3,500
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 107

Hardness in water is caused principally by dissolved calcium and 

magnesium. Excessive hardness in a domestic water supply is 

objectionable principally because of the excessive amounts of soap 

consumed in washing and the scale deposits left in water heating 

equipment. The water of Conchas Reservoir is very hard. If it were 

necessary, the water from Conchas Reservoir could be used satisfactorily as a municipal supply. Treatment to assure sanitary 

purity would be required, and treatment to reduce the hardness 

would be desirable.

REFERENCES CITED

American Public Health Association, 1946, Standard methods for the examination 

of water and sewage, 9th ed.

Collins, W. D., 1923, Graphic representation of analyses: Ind. and Eng. Chemistry, 

vol. 15.

 1928, Notes on practical water analysis: U. S. Geol. Survey WaterSupply Paper 596-H.

Griggs, R. L., 1948, Geology and ground-water resources of the eastern part of 

Colfax County, N. Mex.: New Mexico Bur. Mines and Mineral Res., Ground 

Water Rept. 1.

Hem, J. D., 1948, Fluctuations in concentration of dissolved solids of some 

southwestern streams: Am. Geophys. Union Trans., vol. 29, no. 1.

Hem, J. D., and Hughes, L. S., 1948, Quality of water in the Tucumcari irrigation project, N. Mex., manuscript report in files of U. S. Geol. Survey.

Quality of surface waters of the United States, 1941-46: U. S. Geol. Survey 

Water-Supply Papers. 942, 950, 970, 1022, 1030, 1050.

U. S. Public Health, 1946, Public Health Service drinking water standards: 

Public Health Repts., reprint 2697, vol. 61, no. 11.

Wilcox, L. V., 1948, The quality of water for irrigation use: U. S. Dept. Agr. 

Tech. Bull. 962.

ANALYSES

The following tables summarize the data obtained during the 

period 1939-49 on the quality of inflowing water at Conchas Reservoir and on the quality of water in storage. All analyses in these 

tables for samples collected prior to October 1,1940, and the weightedaverage analyses for the Canadian River for water years prior to 

1944 have not previously been published.
TABLE 1. Chemical analyses, in parts per million of water from Canadia

LOCATION. Various points near site of Conchas Dam. 

RECORDS AVAILABLE. January to July 1936.

EXTREMES, 1936. Dissolved solids: Maximum 1,609 parts per million Mar. 21-27; min

Total hardness: Maximum 804 parts per million Mar. 21-27; minimum 174 parts pe

Date of collection

Mean

discharge 

(secondfeet)

Specific 

conductance 

(Micromhos at

25° C.)

Temporature

PH

Silica 

(Si02)

Iron 

(Fe)

Calcium 

(Ca)

Magnesium 

(MR)

Sodium 

(Na)

Potassium 

(K)

Bicarbonate 

(HCOa)

Sulfate 

(800

Ch

ri

(C

Canadian River 200 feet above confluence with Conch

Jan. 13-20, 1936 

Jan. 21-31- -- 

Feb. 1-10- . _ .

Feb. 11,12, 19, 20. -

Feb. 21-29 

Mar. 1-10 

Mar. 11-20- __ ..

June 13, 16-20 

July 1-4, 6-10 

July 11-. ....

July 13. ......

July 15... .......

July 16... .....

July 17. ........

July 18 

July 19.... .........

37.9

31.5

24.4

23.8

20.3

5.2

1.5

148 

408 

29.8

36.1 

332 

126 

344 

172 

80 

40 

30

6.2 

12 

11 

12 

15 

6.4 

8.6 

12 

17 

19 

18 

15

0.04 

.02 

.02 

.03 

.04 

.02 

.02 

.02 

.06 

.31 

.07 

.06

112 

133 

129 

140 

125 

140 

164 

197 

97 

88 

139 

140 

138 

58 

182 

128 

105 

116 

103

48 

54 

52 

55 

55 

58 

63 

76 

34 

29 

51 

52 

52 

18 

64 

43 

37 

39 

37

91 

102 

109 

107 

104 

127 

164 

221 

69 

54 

107 

114 

1

1 

1 

1( 

!

3.8 

4.3 

4.5 

4.6 

4.6 

5.1 

6.1 

7.7 

5.1 

4.8 

6.2 

6.0 

18 

51 

L5 

15 

)1 

)9 

J5

191 

229 

242 

232 

211 

226 

252 

279 

142 

139 

184 

147 

165 

103 

281 

136 

115 

169 

166

451 

515 

490 

539 

514 

573 

652 

772 

373 

314 

566 

619 

604 

220 

680 

581 

495 

481 

422

1

1
Canadian River at Conchas Dam site below confluence with 

July 12.- - 

July 14-... ... 

8.6 0.05 134 

50 

69

52 

12 

19

111 1 4.8 

53

48

234 

181 

178

483 

105 

166

Canadian River 4 miles below Conchas Dam s

Jan. 22-24, 26, 27, 

29-31, 1936 - _

Feb. 3-7... .... 

13 0.01 134 53 111 3.8 227 500 

479

No flow at gaging station Mar. 14-20. * No flow at gaging st
TABLE 2. Chemical analyses in parts per million, of water from Canadian 

LOCATION. At sites 8 miles downstream to 5 miles upstream from gaging station which 

of Sanchez, 1 mile upstream from Lagartija Creek, and 10 miles downstream from 

DRAINAGE AREA. 5,925 square miles.

RECORDS AVAILABLE. November 1939 to June 1949.

EXTREMES, 1939-40. Dissolved solids: Maximum, 1,942 parts per million May 11, 1

25-31. 

Total hardness: Maximum, 1,045 parts per million May 11, 16-20; minimum, 328 p

EXTREMES, 1939-40. Dissolved solids: Maximum, 2,320 parts per million June 10-1

28-29, 1941.

Total hardness: Maximum, 1,260 parts per million, June 10-11, 1943; minimum, 10

Date of collection

Mean

discharge 

(secondfeet)

Specific

conductance 

(Micromhos at

25° C.)

Temperature 

(° F.)

PH

Silica 

(SiOj)

Iron 

(Fe)

Calcium 

(Ca)

Magnesium 

(Mg)

Sodium

(Na)

Potassium 

(K)

Bicarbonate 

(HO Os)

Sulfate 

(S04 )

Ch

ri

(C

Water Year October 1939 to September 1940

Nov. 11-20, 1939

Nov. 21-30 .......

Dec. 1-6, 9-10-.--,--

Dec. 11-15, 17-20

Dec. 21-22 i ._

10.7

13.0

20.2

16.4

1,420

1,670

1,660

1,690

1,710

7.5

10

8.5

12

0.15

.15

.15

.12

135

159

153

156

62

73

74

77

106

128

129

135

8.2

7.2

6.8

6.4

196

196

190

190

196

613

741

738

760
July 1-2, 4-10------

July 11-13_-...-....

July 21-31. -------

Aug. 1-5 .._-.- 

Aug. 11-19 _______

Aug. 21-23, 25-31...

Sept. 1-10-----.

Sept. 11-20-.. -_--

66.8

5.95

42.9

27.4

1.80

4.72

737

136

251

18.7

55.4

100

47.1

1,270

1,220

1,020

1,910

2,150

1,980

901

858

842

1,020

1,300

893

1,160

14

12

23

17

14

12

25

25

19

31

31

25

19

.16

.08

.04

.18

.01

.08

.02

.08

.10

.04

.05

.08

.09

115

110

90

176

190

164

86

87

93

98

126

90

111

52

48

35

80

94

84

32

27

27

37

46

30

46

98

95

9

20

19

6

6

5

7

10

6

9

7.4

7.2

2

1

5

0

6

3

7

9

9

7

1

153

160

197

149

178

155

198

151

167

187

202

183

179

522

489

358

922

1,049

930

291

308

299

372

521

309

458

Maximum, minimum and weighted average, water year October 19

19.0

8,500

907

1,750

241

557

6.4

15

0.12

.08

158

31

62

84

6.6

18

140

8

30

4.5

5

3.7

198

103

155

810

34

152

35

2

7

Maximum and minimum, water year October 1941 to Se

106

28,000

1,460

455

12 0.18 130

59

68

12

113 2.0

2

210

142

617

114

25

7

Maximum, minimum and weighted average, water year October 19

June 10-11, 1943 

Oct. 18, 1942------

153

3,750

184

2,880

639

1,340 13 6.13

251

65

122

153

18

61

256

54

106

178

125

184

1,506

223

570

69

14

28 

See footnotes at end of table,
112 CONTRIBUTIONS TO HYDROLOGY, 1948-51

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Oct. 1943.-.-.- 1-8, June 29-30, July

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May 1946 < 21-31, . July 17,20--------. Weighted average1

ember 1

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1947.--. Apr. 21-30, May 9 _...__ Weighted average.
Maximum, minimum and weighted average, water year October 19

Nov. 21-30, 1947. -

Aug. 5-7, 1948------

26.7

398

191

1,980-

420

906

7.8

8.2

8.6

20

14

0.02

.03

.04

184

56

93

93

13

37

IfiS

22

59

193

173

179

940

84

326

47

6

15

Maximum and minimum for period October 1948 to Ju

Apr. 1-10, 1949-. __ 

May 17-20- -----

31.1

881

2,250 8.0 

8.1

11 

17

0.01 

.05

198 

81

118 

29

195 

43

179

167

1,140 48 

11

1 Discharge Dec. 21-22 included in discharge reported for Dec. 11-15,17-20.

2 Based on analyses representing 91 percent of total discharge for the water year.

3 Based on analyses 

4 No flow at gage du
114 CONTRIBUTIONS TO HYDROLOGY, 1948-51

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Maximum and minimum, water year October 1942 to Se

July 24-25. .........

9.0

12.5

1,630

463

89 

46

51 

13

213 

34

241 

175

542

77

9

1

Maximum and minimum, water year October 1943 to Se

^ar\t 98 ^fl 1Q44

July 4 6,9, 14-15 

0.2 

10.6

784 

590

172 

182

200 

116

1

1

Maximum and minimum, water year October 1944 to S

Aug. 10-11 

28 

28.5

927 

345

208 

160

242 

33

Maximum and minimum, water year October 1945 to S

2.9

60

1,130

292

250 

135

302 

29

6

Maximum and minimum, water year October 1946 to S

Oct. 4-9, 1946- 

May8, 1947.. 

196 

42

334 

1,640

140 

294

48 

533 8

Maximum and minimum, water year October 1947 to S

May 29-31, June 

1-2, 5-6, 1948 .. 945 

446

258 

196

223

52

4

1

Maximum and minimum, period October 1948 to J

June 21-25, 1949 

June 30, July 1-5, 

8-10--- 

589 

392

190 

174

116

47

2

1 No flow at gaging station. Sampled at head of reservoir.

2 No flow at gaging station.
116 CONTRIBUTIONS TO HYDROLOGY, 1948-51

TABLE 4. Chemical analyses, in parts per million, of water from Conchas Reservoir 

at station 1, Conchas River arm of reservoir about 3,500 feet above dam, water 

years 1939 to 1949

Date of collection

'of

«2n

a

<D

Q

-iSconduc Micromh 

C.)

s§s &§« 02

"3 

0

 3"3

D

1

'$

a03

§

A

"2* is

3*

a a 3 s,

"S's

£>

03

a^

oQ

X!O

SB0

M

^t 

0

00

1

^ ^3 1

0

T3 §

A

D

-3 

1

-d

g "3

CO 8

eg

fes°

B

e

STTRPACE SAMPLES 

Water year October 1938 to September 1939

Apr. 29, 30 _________

May 1-10 

May 11-20- ___ . __ ....

May 21-31 

June 1-10 ________

June 21, 28.. - .- -

July 5, 12, 19, 26- ....

Aug. 2,9, 16, 23, 30. ... .

Sept. 6, 13, 20, 27 - 

1,160

1,150

1,100

1,090

1,060

1,040

1,020

981

825

748

116

<K

91

74

fid

K/l

35

27

90|7. 0

79

56

53

10^

188

185

183

180

176

174

156

144

481

457

443

397

364

287

251

OC

22

20

20

23

21

16

14

Q7Q

728

675

KAK

485

511

422

396

qoQ

ooq

Water year October 1939 to September 1940

Oct. 4, 11, 18, 28, 1939. -

Nov. 8, 15, 22, 29-. ...

Dee. 6, 13, 20, 27- 

Jan. 10, 17, 25, 31, 1940 

Feb. 7, 15, 21, 28__ ... .

Mar. 6, 13, 20, 27- -

Apr. 3, 10, 17, 24___ _ -

May 1, 9, 16, 22, 29 . .

June 5, 12, 19, 26 .....

July 12, 18, 31. __ ......--

Aug. 8, 14, 22... ...........

Sept. 3, 11, 18, 25 .......

748

762

760

804

838

841

848

866

884

888

63

74

27

27

64

52

148

146

154

153

158

153

156

152

150

146

148

257

258

13

14

15

16

17

19

19

19

18

497

4.O7

268

296

Maximum and minimum, water year October 1940 to September 1941

Mar. 5, 9, 12, 1941 r ._

Sept. 4,18,23.. 

982

542

160

127

22

10

Maximum, minimum, and intermediate analyses, water year October 1941 to September 1942

Aug. 6, 13, 20, 25, 1942.....

May 7, 8, 15, 28, 1942 ...

638

464

622 fin 23 40

115

141 189

9.0

13 394 244

Maximum, minimum, and intermediate analyses, water year October 1942 to September 1943

Sept. 2, 10, 16, 23, 30, 1943-

Feb. 3,12, 18, 26, 1943.. 

893

612

782 69 29 59

156

138

148

186

265

14

15 511 291

Maximum and minimum, water year October 1943 to September 1944

June 15, 22, 1944__.........

Ont 7 1 4. 91 9S 1 Q4.3

1 1,020

914

165

160

384

Maximum and minimum, water year October 1944 to September 1945

JuneS, 14, 23, 30, 1945.- 

Oct. 6,12, 1944........ .

a 1,070

3 1 ,010

165 411

379

See footnotes at end of table.
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 117

TABLE 4. Chemical analyses, in parts per million, of water from Conchas Reservoir 

at station 1, Conchas River arm of reservoir about 3,500 feet above dam, water 

years 1939 to 1949 Continued

.Date of collection o> 

 2

a "a

0)

Q

conduct- Specific (Micromhos ance 

C.) 25° at

Calcium (Ca)

"Si

§

'to

pg> 1

Sodium andpotassium (Na+K)

Bicarbonate 

(HC0 )3

(SO4) Sulfate Chloride (Cl)

Dissolved solids Total hardness as 

CaCO>

Maximum and minimum, water year October 1945 to September 1946

June 1, 8, 15, 21, 28, 1946 

Oct. 5, 12, 18, 25, 1945- 

1,150

1,070

450 

156 405

Maximum and minimum, water year October 1946 to September 1947

Dec. 3, 11,18, 27, 1946.. 

June5, 10, 17, 26, 1947. 

981 

1,040 85 40 82

150 

159

367 

378 22 686 376

Maximum and minimum, water year October 1947 to September 1948

May 5, 11, 28, 1948 

Sept. 6, 14, 20, 27, 1948 -

1,070

« 1,010

161 410 

387

24

Maximum and minimum, for period October 1948 to July 1949

June 8, 13, 26, 1949 

Oct. 4, 22, 26, 1948 

1,070

1,010

420 

405

SAMPLES FROM DIFFERENT DEPTHS

XTnTT 7 1 Q^Q

Sept. 10, 1941. . 

Feb. 13, 1942--- 

Apr. 3, 1944... _ . _

25

50

84

25 

50

75 

93

25

50

75

100

105 

110

115

120

125

25

5078- 

83

88

93

98

103

25

50

75

100

113

118

123

128

758

761

765

773

543

544 

540

535 

559 

589

591

587

597

592

704 

742

750

752

767

697

696

701

819 

825

823

822

820

824 

1,010

992

995

1,000

995

1,000

1,000

1,000

1.010

54

52 

64 

60

74

68

80

77 

84

19

19 

18 

20

26

94.

32

31 

40

32

29 

28 

39

45

46

60

61 

84

150

151

152

153

127

127 

127

126 

166 

144

160

168

141

155

156

168

167

180

159

151 

141 

175

231

248

991

298

290 

370

9.0

9.0 

10

8.0 

8.0 

11

12

13

16

17

16 

25

336

321 

341 

377

468

AAK

564

552 

685

212

208 

234 

232

292

268

331

320

VIA

See footnotes at end of table.
118 CONTRIBUTIONS TO HYDROLOGY, 1948-51

TABLE 4. Chemical analyses, in parts per million, of water from Conchas Reservoir 

at station 1, Conchas River arm of reservoir about 3,500 feet above dam, water years 

1939 to 1949 Continued

Date of collection <D 8

01

P

. M

<j i< ;d -5 "2 o

Specific coi (Micr ance 25° C.) at

O

6 

,2"3 

O

'hfl

^f

o

Magnesium

,

C^x-^ -gK>

ft 1

Sodium andsium (Nao.

03

B^~.

icar hBo(HCOs

.

^^

Sulfate (SO

Z3

Chloride (C

TJ

s

1

(3

w

s

"o

SAMPLES FROM DIFFERENT DEPTHS Continued

Jan. 12, 1945. ....... .......

July 16, 1947__. __---.-...

Apr. 27, 1948_..___. .......

Oct. 19, 1948_. .............

25

50

75

100

105

110

115

120

50

75

95

100

105

110

115

120

25

50 

75

100

105

110

115

120

125

25

50

75

102

107

112

117

25

50

75

100

105

110

115

120

1,010

1,020

1,020

1,020

1,050

1,050

1,050

1,040

1,080 

1,130

1,120

1,120

1,120

1,120

1,120

1,120

1,120

1,020

1,030 

1.020

1,020

1,020

1,600

1,070

1,060

1,070

1,070

1,070

1,090

995

1,010

1 040

1,030

1,030

86

99

86

42

43

38

83

84

89

162

186 

167

160

161

160

175

148

152

172

214

384

402 

435

386

406

412

415

386

383

385

385

24

24 

28

21

27

25

30

24

23

23

23

699

746

699

387

424

370

1 Also reported for period May 4, 11, 20, 28, June 9, and July 14, 18. 

» Also reported for period July 4,19, 27, and Aug. 4, 11, 19, 23, 29.

3 Also reported for period Dec. 7, 16, 21, 30.

4 Also reported for period Aug. 3, 9, 16, 24, 30.
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 119

TABLE 5. Chemical analyses, in parts per million, of water from Conchas Reservoir at station 2, at upstream face of main section of Conchas Dam, water Hears 

1939 to 1949

[See fig. 12)

Date of collection 1

Q

 g o

3*

oS?

a* *

CO

03

O

s

 3

D

If

a a

s

C3

g

.

g,^

6~s

 §3 X"55

s

a.

03

00

o

.^

M

6

CO

&

O

a.

o

J3

0

T3

g

T3 

o

1

5

s

|o 1° *r

03

O

SURFACE SAMPLES

Water year October 1938 to September 1939

Apr. 8, 1939-....... ....

Apr. 29-30- 

May 1-10 ...-. ....

May 11-20 

May 21-31- ............

June 1-2, 4-10 ------

June 11-20 -

July5, 12, 19,26-- . 

Aug. 2,9, 16,22,30- -

Sept. 6, ,13; 20, 27 ------

~*

1,120

1,130

1,090

1,070

1,050

1,030

976

814

737

114

98

92

76

68

55

45

41

35

27

886.2

75

70

51

51

193

187

183

177

182

176

176

152

141

479

453

440

394

362

289

249

24

21

22

19

23

21

21

14

12

870

725

673

540

476

510

430

398

334

280

Water year October 1939 to September 1940

Oct. 4, 11, 18, 28, 1939.. 

Nov. 8, 15, 22,29 . 

Jan. 10, 17, 25, 31, 1940 

Feb. 7, 15,21,28 

Mar. 6, 13; 20, 27 

May 1,9, 16,22,29 

JuneS, 12, 19.26--- 

July 12, 18,31. 

Aug. 8, 14,22 -.

Sept. 3, 11, 18,25- 

749

744

7fi4

767

796

808

837

846

872

894

68

72

26

25

61

58

146

149

155

-154

154

157

157

156

157

150

146

148

261

256

13

14

15

15

18

17

19

18

19

431

498

276

282

Maximum and minimum, water year October 1940 to September 1941

Mar. 5, 12, 19, 1941 

Sept. 4, 18,23 .. 

985

543

158

128

20

9.0

Maximum, minimum, and intermediate analyses, water year October 1941 to September 1942

Oct. 1, 9, 15, 22, 1941 

May 7, 8, 15,28, 1942 

638

466

622 60 23 40

114

138 192

7.0

12 395 244

Maximum, minimum, and intermediate analyses, water year October 1941 to September 1942

Sept. 2, 10, 16, 23, 30, 1943 .

Peb. 4,12, 18,26, 1943.---

896

609

781 70 29 60

156

133

151 265 16 515 294

Maximum and minimum, water year October 1943 to September 1944

Oct. 7, 14, 21, 28, 1943 - 908

166

161

385

Maximum and minimum, water year October 1944 to September 1945

Nov. 16, 23, 30, 1944---....

»1, 070

'1,010 379

See footnotes at end of table.
120 CONTRIBUTIONS TO HYDROLOGY, 1948-51

TABLE 5. Chemical analyses, in parts per million, of water from Conchas Reservoir at station 2, at upstream face of main section of Conchas Dam, water years 

1939 to 1949 Continued

Date of collection I 

.a "a

0)

Q

Specific conduct- (Micromhos ance 

C.) at 25°

Calcium (Ca)

I

*w

05

1

Sodium andpotassium (Na+K)

icarbonate B

(HCOj) ^

O

CQ

I

1 

03

Chloride (Cl)

2 "3

T3

1

5

Total hardness as

CaCOj

Maxmum and minimum, water year October 1945 to September 1946

July 5, 20, 25, 1946 _ ....

Oct. 5, 12, 18, 25, 1945 .

1,150

1,060 158

447 

415

Maximum and minimum, water year October 1946 to September 1947

June5, 10, 17, 26, 1947 -

NOY. 13, 23, 27, 1946 

^ 1,030 

976

84 41 81 159 381 

371

19 685 378

Maximum and minimum, water year October 1946 to September 1947

May 5, 11, 21, 28, 1947 -.

Sept. 6, 14, 20, 27 .......

H,060

61, 010

165 412 

383

25

Maximum and minimum, period, October 1948 to July 1949

June 3, 8, 26, 1949..........

Oct. 4, 22, 26, 1948 

1,070 

1,010

416 

394

SAMPLES FROM DIFFERENT DEPTHS

Nov. 7, 1939 ____ .

Apr. 23, 1940 

Sept. 10, 1941.. __ .... ...

Feb. 13,1942..... .....

Dee. 17, 1942. ______ ...

25

50

70

90

25

50

75

86

88

25 

50

75

100 

125

25

50

75 

100

111

116

121

126 

131

25

 ;n

75 

112

117

122

127

132

772

760

766

770

1,390

833

841

848

848

900

541

541 

539

529

499 

603

Ron

587

590

591 

675

734

704

744

757 

832

703

699

704

823

823

828

828

827

54

52

61

77

60

88

82

18

17

21

30

25

29

33

34

27

38

52

60

47

53

150

151

152

153

816

164

164

162

174

198

127

129 

128

128

126 

268

143 

156

170

148

157

166

158

139 

98

182 

221

257

230

276

293

9.0

9.0 

9.0

9.0

8.0 

8.0

10 

12

14

15

17

16

337

305

383

515

464

535

554

208

200

238

314

252

338

340

See footnote at end of table.
*~* 

S

W* OS* W* W* W* 

O 0 O O O 

i-« >-l i-s >-l >-< i-«

g 0 0 0 0 0

CD CD CD CD CD CD

dO.o.O'O.p,

g o o o o o

 period May4, 11,2

period June8, 14,2period Oct.6,12 ai 

 period July2,10, 1

period April 1,71

period Aug.3, 91C

£~88og8

g wo P>IH 

PC-50

JS 9"

to

JO

0 !> g > «

?* p <<] r* 

5 M S g 

» 00 -J OS 

cc cc en

II 1

00 

& 

8SSS838S8S888S83888SSS8SSg838S8SSKiSSS8S38S8i3l3QS9838

OOCO^wCO|s300HJt^h^^^^^^-vjo^OOlN3*^ls3HJ|s3is3is3is3COhJCOCOIs3b3M

§

CO

cS

*

s

i

*

s

Oi

»

Cn O5

COOO

SB

il

00 CO

to

Cn

S

&

00

»£k

S

CO 

00

So

8

03

g

CO

8

£

§

IS

it". CO

coco

CJT CO

ill

§

00
122 CONTRIBUTIONS TO HYDROLOGY, 1948-51

TABLE 6. Chemical analyses, in parts per million, of water from Conchas Reservoir at Station 3, Canadian River arm of reservoir about 1,300 feet above dam, 

water years 1939 to 1949

[See fig. 12]

Date of collection

S3"a.

0)

Q

, 01 "o

1.1 .iju US*

?

O> *O

g«

Q« 03 03

1

"oS

O

p

'3

"3

O

i-""

§,

6 

 53s

Sc

bo

03

§

0§

a_jl

«§.'

.3 § ^ 'S

lg

0)

03 

O~ <=6

^~* M

a

 ^

eq

^.^

o

CO

-2

03

1

O

a)

TJ

|

3

O

2"o

TJ

f»

§

5

M

03

i.

|p

^0"3

O

EH

SURFACE SAMPLES

Water year October 1938 to September 1939

Apr. 8, 1939..._. ...........

Apr. 29, 30. ...............

May 1-10-- --.---..

May 11-20._. ...... ...... .

May 21-31 

June 1-2, 4-10- - 

June 11-20 .. __ .

June 21, 28-- .

July 5, 12, 19, 26 

Aug. 2,9, 16, 23,30. 

Sept. 6, 13, 20, 27 

1,140

1,120

1,090

i nfifl

1,010

970

816

735

96

74

68

54

45

35

26

89 5.6

72

51

56

192

186

183

177

176

176

172

1 KK

142

480

449

437

391

283

253

24

19

20

18

21

21

22

13

13

869

712

532

486

424

328

276

Water year October 1939 to September 1940

Oct. 4, 11,18, 28, 1939 

Nov. 8, 15,22, 29---_-_. .

Dee. 6, 13, 20, 27 

Jan. 10, 17, 25, 31, 1940 

Feb. 7, 15, 21, 28. 

Mar. 6, 13, 20, 27 

Apr. 3, 10, 17, 24. -

May 1, 9, 16, 22, 29 

June5, 12, 19, 26.-.-. .

July 12, 18, 31. . ....

Aug. 8, 14, 22.... ....

Sept. 3, 11, 18, 25. -

»,

752

741

798

810

839

858

881

QQfi

896

68 27

26

56

55

146

148

153

154

158

158

157

156

151

146

147

253

257

13

16

16

14

17

19

19

18

18

489

501

280

" 292

Maximum and minimum, water year October 1940 to September 1941

Mar. 5, 12, 19, 26, 1941..

June 11, 18, 25 

986

1 544

160

116

20

9.0

Maximum, minimum, and intermediate analyses, water year October 1941 to September 1942

Aug. 6, 20, 25, 1942-.. .

Oct. 1, 9, 15, 22, 1941 

May 7, 8, 15, 28, 1942._._ __

652

618 22 37

114

138 189

9.0

10 387 242

Maximum, minimum, and intermediate analyses, water year October 1942 to September 1943

Sept. 2, 10, 16, 23, 30, 1943-

Oct. 7, 1942_______. ________

Feb. 3, 7, 12, 18, 26, 1943

917

621

762 62 28 65

157

143 254 20 500 270

Maximum and minimum, water year October 1943 to September 1944

June 15, 22, 1944 ... .

Oct. 7,14,21,28,1943 .. 910 162

379

Maximum and minimum, water year October 1944 to September 1945

July 4, 19, 27, 1945 

Oct. 6, 12, 1944... .. '1,010

161 413

379

See footnotes at end of table.
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 123

TABLE 6. Chemical anayses, in parts per million, of water from Conchas Reservoir at Station 3, Canadian River arm of reservoir about 1,300 feet above dam, 

water years 1939 to 1949 Continued

Date of collection

a 

a

Q

Specific conduct- (Micromhos ance 

25° C.) at

Calcium (Ca)

Magnesium (Mg)

S~

SM

-at

§5,

ll

Bicarbonate 

(HCOs)

Sulfate (SO )4

Chloride (Cl)

Dissolved solids

Total hardness as

CaCOs

Maximum and minimum, water year October 1945 to September 1946

June 1, 8, 15, 21, 28, 1946-.

Oet. 5,12,18,25,1945 .-

4 1,140

1,060 153

468 

414

Maximum, minimum, and intermediate analyses, water year October 1946 to September 1947

July 2, 10, 16, 23, 31, 1947- .

Nov. 13, 23, 27, 1946...-.-.

June5, 10, 17, 26, 1947.. ...

1,030 

978 

1,030 84 40 85

160

159

389 

372 

383 21 692 374

Maximum and minimum, water year October 1947 to September 1948

May 5, 11, 21, 28, 1948... ..

Sept. 6, 14, 20, 27----------

1,070 

988

163 409 

379

23

Maximum and minimum, for period October 1948 to July 1949

June 8, 26, 1949 . -

Oct. 4, 22,26, 1948------ --

1,070

1,000

417 

392

SAMPLES FROM DIFFERENT DEPTHS

Nov. 7, 1939--... . .-__

Sept. 10, 1941---------.._-

Feb. 13, 1942. ......... ..._

Dee. 31, 1942-.. --__--.. ..

10

20

30

40

50

60

70

80

83

84

86

25 

50

75

100 

125

25 

50

75

100

106

111

116

121 

126

25

50

75

81

85

91

96

101

768

760

765

768

770

775

770

774

764

807

ZAK

538

529

497 

621

587

584 

585

584

695

754

751

751

761 

761

742

738

740 7dt;

746

749

748

757

898

56

52 

82

61

78

71

96

18

17 

22

20

29

26

32

30

23 

25

38

51

CO

62

151

150

151

152

1 =.3

1 =.9

154

179

840

126 

128

128

124 

254

143

170

148

217

156

132 

126

177

230

254

291

9.0

9.0 

9.0

10

8.0 

7.0

11

12

13

15

17

331

293 

387

378

510

484

606

214

200 

295-

234

314

284

371

See footnotes at end of table.
124 CONTRIBUTIONS TO HYDROLOGY, 1948-51

TABLE 6. Chemical analyses, in parts per million, of water from Conchas Reservir at Station 3, Canadian River arm of reservoir about 1,300 feet above dam, 

water years 1939 to 1949 Continued

Date of collection (feet) pth 

£>

Q

' S

o $

|1!l? i§®t»

"c?

0

a i

6

*h/l

a

 3

1

i

and pol ium 

(Na+K um 

0 w

02

e

-4_3

b aoncar

(HCOj)

«

O 02

£

o

0) 

TJ

s

D

rf.

solid solved 

fi

S

tal hardness 

CaCOj

o 

EH

SAMPLES FROM DIFFERENT DEPTHS Continued

Apr. 3, 1944.. .............

Jan. 12, 1945... ____ .....

Apr. 29, 1946 _ ...........

July 16, 1947.. _ .......

Apr. 27, 1948-.......... 

Oct. 19, 1948 ............

25

50

75

100

108

117

121

126

131

136

25

50

75

100

105

110

115

125

25

50

75

100

105

110

115

120

25 

50

75

100

105

110

115

120

122

25

50

75

105

110

115

120

125

25

50

75

95

100

105

110

115

995

992

992

995

997

995

997

1,000

1,010

1,010

1,020

1,030

1,030

1,020

1,020

1,040

1,050

1,050

1,050

1,080 

1,130

1,120

1,120

1,120

1,120

1,120

1,120

1,120

1,110

1,040

989 

1,030

1,020

1,020

1,010

1,010

1,010

1,020

1,440

1,070

1,070

1,060

1,070

1,070

1,070

1,070

1,070

1,180

1,020

1,010

1,010

1,020

1,020

1,030

1,040

1,030

1,140

84

86

98

84

83

41

4.0

44

38

80

83

73

84

80

170

168

168

171

164

186 

166

171

156

149

934

161

367

151

154

166

272

366

386

380 

434

428

ODD

374

4.HQ

326

385

387

388

400

23

24

24

O7

27

20

18

f>4

23

24

20

25

678

703

712

RCU

667

378

392

426

378

363

' Also reported for period Sept. 4,18, 23.

J Also reported for period June 8,14, 23, 30 and Aug. 4, ll, 19, 23, 29.

* Also reported for period Nov. 2, 9.

«Also reported for period May 4,12,18, 24, July 5, 20, 25, and Aug. 3,13, 21, 31.
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 125

TABLE 7. Chemical analyses, in parts per million, of water samples from different 

depths, Conchas Reservoir at Station 6, Conchas River arm of reservoir 5 miles 

above dam, water years 1941 to 1949

Date of collection

Oct. 15, 1941...............

Jan. 17, 1942. __ .........

Dec. 17, 1942.. ............

Apr. 3, 1944.... __ ......

Jan. 12, 1945.. ..........

Apr. 29, 1946... ...........

July 16, 1947.... _ ........

Apr. 27, 1948... ___ .....

Jan. 26, 1949.......... _ ..

1 

a 

aCD

Q

25 

v>

58

63

68

73

75

78

25

50

75 

on

95

100

105 

110

25

Krt

71 

76

Q1

86

91

96

95

50

75

80

85

90

95

95

50

70

75

80

85

90

25

Krt

70

75

en

85

90

25

50

70

75

80

85

on

95

25

50

70

75

80

85

90

25

50

65

70

75

80

85

90

Specific conduct- (Micrombos ance 

C.) 25° at

450

448

AAK

443

442

43A

435

443 

496

KKK

KC7

KKK

552 

566

708

721

725

79 K

685

680

680

734 

758

QflO

817

775

833 

992

989

QQQ

QQQ

989

986

989

995 

1,020

1,020

1,020

1,020

1,020

1,030

1,020

1,110 

1,130

1,130

1,120

1,120

1,120

1,130

1,120

1,130

1,040

1 fl^ft

1,030

1,020

1,020

1,020

1,030

1,020

1,030

1,070

1,070

1,060

1,070

1,060

1,070

1,070

1,080

1,040

1,040

1,040

1,040

1,040

1 040

1,050

1,080

Calcium (Ca)

44

44

57

74

68

72

84 

85

90

87

112

84

Magnesium (Mg)

14

14

18

27

24

25

30

49

40 

43

43

42

Sodium andpotassium (Na+K)

28

26

37

47

52

60

61

85

74 

79

84

82

Bicarbonate 

(HCOs)

116

114 

116

114

114

113

112

114 

154

138

165

149

150

176 

165

167

172

159 

162

232

168

156

1fi4

173

158

189

(SO )Sulfate 4

118

115 

120

160

235

229

255

286 

372

373

383

399 

433

387

408

414

396

406

Chloride (Cl)

9.0

8.0 

9.0

7.0

9 n

8.0

7.0

8.0 

8.0

12

12

15

17

16 

34

22 

24

24

21

25

23

solids Dissolved 

268

263

352

477

466

503

569 

699

677 

696

777

693

Total hardness as

CaCOs

168

168

216

296

268

282

333

384

389 

394

456

382
126 CONTRIBUTIONS TO HYDROLOGY, 1948-51

TABLE 8. Chemical analyses, in parts per million, of water samples from different 

depths, Conchas Reservoir at Station 7, Canadian River arm of reservoir 5 milesabove dam, water years 1941 to 1949

[See figure 12]

Date of collection

Oct. 15, 1941... ............

Jan. 17, 1942-. ............

Dec. 31, 1942..............

Apr. 3, 1944. ..............

Jan. 12, 1945^.. .

Apr. 29, 1946..............

July 16, 1947.... ...........

S

"" 

<**

a

& 

Q

25 

50

75

85

90

95

100

100

105

25

50

75

97

100

102

107

112

117

25

50

60

65

70

75

80

85

25

50

75

97

102

107

112

. 117

25

50

75

88

93

98

103 

108

Surface

25

50

75

82

87

92

97

102

107

25 

50

75

100

105

110

115

120

Specific conduct- (Micromhos ance 

25° C.) at

464

460 

501

519

543

550

560

581

596

639

594

593

605

603

629

633

642

702

786

771 

768,

772

779 '778

777

780

784

782 

834 

1,010

1,010

1,010

1, 030

1,020

1,040

1,050

1,050

1,010

1.-020

1,030

1,030

1,040

1,060

1,060

1,060

1,070 

1,070

1,130

1,120

1,120

1,130

1,140

1,130

1, 130

1,130

1,130

1,150

1,040

989 

1,000

1,000

1,000

1,010

1,010

1,010

1.010

Calcium (Ca)

*

47

86 

72

74

84 

89

89

94

QO

82

Magnesium (Mg)

17

91

28

00

29 

30

49

d3

46

41

38

Sodium andpotassium (Na+K)

23

QQ

47 

62

60 

60

QQ

76

80

QQ

80

Bicarbonate 

(HCOs)

115

114 

122

123

132

132

133

139

140

178 14<;

201 

ISO

152 

167 

174

168

172

173

162

168

168

178

1 CO

146

Sulfate (SOi)

128

178

176

181

237

973

273 

292

385

410

438

436

9QE

372

Chloride (Cl)

7.0

7.0 

7.0

9.0

9.0

8.0

9.0

10

10

10

13 

16

17 

16 

24

22

24

26

26

91

20

Dissolved solids

278

385

513

KOC

528 

566 

726

695

737

702

664

Total hardness as

CaCOs

188-

9J.U

330

9Q±

304 

333 

394

349

424

37<4

360
QUALITY OF WATER, CONCHAS RESERVOIR, N. MEX. 127

TABLE 8. Chemical analyses, in parts per million, of water samples from different 

depths, Conchas Reservoir at Station 7, Canadian River arm of reservoir 5 miles 

above dam, water years 1941 to 1949 Continued

Date of collection

Jan. 26, 1949-..............

IB 

<2

.a"a 

® 

P

25

80

85

90

95

100

25

50

75

80

85

90

95

100

105

Specific conduct- (Micromhos ance 

C.) 25° at

1,070

1,070

1,070

1,090

1,090

1,090

1,230

1,020

1,030

1,030

1 030

1,030

1,030

1,030

1,030

1,030

1,130

Calcium (Ca)

Magnesium (Mg)

Sodium andpotas- 

(Na+K) sium 

Bicarbonate 

(HC0 )3

163

166

277

158

Sulfate (SO)4

409

424

437

398

Chloride (Cl)

25

24

21

Dissolved solids

Total hardness as

CaCOs

o