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Sumner County Geohydrology

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Ground Water, continued

Chemical Character of the Water

The chemical character of ground water in Sumner County is indicated by the analyses of 219 samples given in Table 6, and the analyses of 13 samples shown graphically in Figure 9. The analyses were made by Howard Stoltenberg in the Water and Sewage Laboratory of the Kansas State Board of Health. Samples of water were collected from wells and test holes distributed as uniformly as possible within the county and representing the principal water-bearing formations of the area. Analyses of samples from all municipal supplies and of samples collected during 1943 and 1944 as part of an earlier study also are included. In areas where the ground water has been contaminated by oil-field brines, samples were collected from closely spaced test holes to determine the extent of contamination. Analyses of 15 samples of surface water (Table 7) are included to show the effects of contamination. Because chloride and sulfate are the critical constituents in ground water in much of Sumner County, 71 samples were analyzed only for one or both of these substances.

Figure 9--Graphic representation of analyses of water from principal water-bearing formations in Sumner County.

water from Wellington Fm is worst; Nebraskan Terrace is best

The relation of the geology to the quality of water in an aquifer is discussed in a later section.

The results of the analysis of water samples listed in Table 6, Table 7, and Table 8 are given in parts per million. Factors for converting parts per million of mineral constituents to equivalents per million are given in Table 9. The parts per million of a constituent are multiplied by the conversion factor to obtain the equivalents per million of that constituent.

Table 7--Partial analyses of water from wells and test holes in Sumner County.

Well number Depth,
feet
Geologic
source
Date of
collection
Temperature
(deg. F)
Sulfate
(SO4)
Chloride
(Cl)
30-2E-6bcb 47-52 Wisconsinan terrace deposits 5/23/1944     114
30-2E-6bdd 20-25 Wisconsinan terrace deposits 5/23/1944     33
30-2E-7abc1   Wisconsinan terrace deposits 9/8/1955     147
30-2E-17acb1 38.6 Wisconsinan terrace deposits 8/9/1956   1,240 65
30-2E-17bba 50-55 Wisconsinan terrace deposits 5/20/1944     54
30-2E-19aba 67-72 Wisconsinan terrace deposits 5/20/1944     43
30-2E-19bcc 46-51 Wisconsinan terrace deposits 5/19/1944     34
30-2E-19ccb 39-41 Alluvium 6/14/1956     24
30-2E-20ccc 20 Wisconsinan terrace deposits 8/23/1943 62   20
30-2E-28aba 20 Alluvium 8/23/1943 64   76
30-2E-29aab 58-60 Wisconsinan terrace deposits 6/18/1956     347
30-2E-29aba2 54-56 Wisconsinan terrace deposits 6/14/1956     451
30-2E-29add 37-39 Wisconsinan terrace deposits 6/18/1956     328
30-2E-29baa 56-58 Wisconsinan terrace deposits 6/18/1956     435
30-2E-29bbb 47-49 Wisconsinan terrace deposits 6/14/1956     31
30-2E-30ccc 11-13 Wisconsinan terrace deposits 9/7/1955     14
30-2E-30dba 36.3 Wisconsinan terrace deposits 8/9/1956   46 16
30-2E-33bbb 20 Wisconsinan terrace deposits 8/23/1943 62   15
30-2E-34bbb 17-19 Alluvium 6/13/1956     39
30-1E-1aac 45-50 Alluvium 6/8/1944     118
30-1E-1abb 47-49 Wisconsinan terrace deposits 7/3/1956     143
30-1E-1acd 34-36 Alluvium 7/4/1956     82
30-1E-2abb 51-56 Wisconsinan terrace deposits 6/9/1944     81
30-1E-3aaa 45-47 Wisconsinan terrace deposits 7/4/1956     33
30-1E-3abb 33-38 Wisconsinan terrace deposits 6/9/1944     28
30-1E-3bbb 19-21 Wisconsinan terrace deposits 9/5/1956     18
30-1E-4aab 9-14 Wisconsinan terrace deposits 6/9/1944     20
30-1E-4bab 25-30 Illinoisan or Kansan terrace deposits 6/9/1944     29
30-1E-6bbb 61-67 Illinoisan or Kansan terrace deposits 6/7/1944     22
30-1E-9add 26-28 Illinoisan or Kansan terrace deposits 7/5/1956     17
30-1E-11aaa 48-50 Wisconsinan terrace deposits 7/3/1956     75
30-1E-13bab 20 Wisconsinan terrace deposits 8/23/1943     24
30-1E-13daa 33.0 Wisconsinan terrace deposits 9/7/1955     23
30-1E-14aaa 58-60 Wisconsinan terrace deposits 7/3/1956     31
30-1E-14ccd 20 Wisconsinan terrace deposits 8/23/1943 65   40
30-1E-18cbc 30.0 Wisconsinan terrace deposits 9/1/1955     235
30-1E-23aab 19-21 Wisconsinan terrace deposits 7/3/1956     27
30-1E-25aba 20 Wisconsinan terrace deposits 8/23/1943     45
30-1E-25baa 31-36 Wisconsinan terrace deposits 5/18/1944     28
30-1E-28ccc 30-32 Wisconsinan terrace deposits 9/7/1955     40
30-1E-33cdc 29-31 Wisconsinan terrace deposits 6/7/1956     755
30-1E-33ddd 29-31 Alluvium 6/6/1956     70,100
30-1E-34add 25-27 Wisconsinan terrace deposits 8/11/1956     11,700
30-1E-34bbc 31-33 Wisconsinan terrace deposits 6/6/1956     178
30-1E-34bcc 40-42 Wisconsinan terrace deposits 6/6/1956     15,100
30-1E-34ccb 36-38 Wisconsinan terrace deposits 6/6/1956     64,400
30-1E-34ccd 37-39 Alluvium 6/8/1956     115,000
30-1E-34dcd 37-39 Alluvium 6/8/1956     12,200
30-1E-35aaa 36-38 Illinoisan or Kansan terrace deposits 9/7/1955     15
30-1E-35bcc 20-25 Wisconsinan terrace deposits 5/17/1944     96
30-1E-35cbc 31-33 Wisconsinan terrace deposits 6/11/1956     2,070
30-1W-2abb 30-35 Wisconsinan terrace deposits 6/7/1944     15
30-1W-5abb 29-31 Wisconsinan terrace deposits 8/31/1955     13
30-1W-13aaa 40.0 Wisconsinan terrace deposits 9/1/1955     71
30-4W-23ddd 45.8 Ninnescah Shale 8/13/1956   58 27

Well number Depth,
feet
Geologic
source
Date of
collection
Temperature
(deg. F)
Sulfate
(SO4)
Chloride
(Cl)
31-2E-2ddd 17-19 Wisconsinan terrace deposits 6/18/1956     8.0
31-2E-3aba 12-14 Alluvium 6/29/1956     14
31-2E-3baa 19-21 Alluvium 6/18/1956     36
31-2E-3bbb 48-50 Wisconsinan terrace deposits 6/12/1956     54
31-2E-3cbb 20 Alluvium 8/23/1943     43
31-2E-3ddd 24-26 Alluvium 6/29/1956     52
31-2E-5cdd 20 Wisconsinan terrace deposits 8/23/1943 62   27
31-2E-5ddd 48-50 Wisconsinan terrace deposits 6/12/1956     18
31-2E-7ccc 31-33 Wisconsinan terrace deposits 9/8/1955     6.0
31-2E-9adb 61.8 Wisconsinan terrace deposits 8/13/1956   166 26
31-2E-11ada 20 Wisconsinan terrace deposits 8/23/1943 63   29
31-2E-12bcc 16-18 Wisconsinan terrace deposits 6/19/1956     19
31-2E-13bba 17-19 Wisconsinan terrace deposits 6/19/1956     31
31-2E-13bca 21-23 Wisconsinan terrace deposits 6/19/1956     48
31-2E-13cca 28-30 Wisconsinan terrace deposits 6/20/1956     36
31-2E-14aab 29-31 Wisconsinan terrace deposits 6/19/1956     48
31-2E-15aaa 48-50 Wisconsinan terrace deposits 6/12/1956     48
31-2E-16aaa 20 Wisconsinan terrace deposits 8/23/1943     18
31-2E-17cdc 25 Wisconsinan terrace deposits 8/23/1943     40
31-2E-20ddc 25 Alluvium 8/26/1943     24
31-2E-24bab 20-22 Wisconsinan terrace deposits 9/10/1955     47
31-2E-24cdd 42-47 Wisconsinan terrace deposits 5/25/1944     85,500
31-2E-24dca 18-20 Wisconsinan terrace deposits 6/20/1956     64,700
31-2E-24dcc 39-41 Wisconsinan terrace deposits 6/20/1956     430
31-2E-25aba 36-38 Wisconsinan terrace deposits 6/20/1956     27,500
31-2E-25ada 11-13 Wisconsinan terrace deposits 6/20/1956     915
31-2E-25cac 28-30 Alluvium 6/21/1956     515
31-2E-25cad 27-29 Alluvium 6/21/1956     2,080
31-2E-25dcc 42-47 Alluvium 5/26/1944     74,200
31-2E-25dda 47-49 Wisconsinan terrace deposits 6/20/1956     37,400
31-2E-25ddd 41-43 Wisconsinan terrace deposits 9/10/1955     56,400
31-2E-26bbb 27-29 Wisconsinan terrace deposits 9/9/1955     18
31-2E-26ddd 18-23 Wisconsinan terrace deposits 5/13/1944     28
31-2E-27aaa 25 Wisconsinan terrace deposits 8/26/1943 62   42
31-2E-34aba 28 Wisconsinan terrace deposits 8/26/1943 62   24
31-2E-36aad 34-36 Alluvium 6/21/1956     23,600
31-2E-36abb 11-13 Alluvium 6/21/1956     760
31-2E-36acb 10-12 Alluvium 6/21/1956     485
31-2E-36dca 9-11 Alluvium 6/28/1956     510
31-2E-36dcd 9-11 Alluvium 6/28/1956     490
31-1E-2baa 17-19 Wisconsinan terrace deposits 6/12/1956     54
31-1E-2bad 21-23 Wisconsinan terrace deposits 6/12/1956     78
31-1E-2bbb 30-32 Wisconsinan terrace deposits 6/11/1956     1,590
31-1E-2bcc 30-32 Wisconsinan terrace deposits 6/11/1956     595
31-1E-3baa 37-39 Wisconsinan terrace deposits 6/8/1956     160,000
31-1E-4aab 34-36 Wisconsinan terrace deposits 6/7/1956     20,400
31-1E-4aac 24-26 Wisconsinan terrace deposits 6/7/1956     6,080
31-1E-4adc 34-36 Wisconsinan terrace deposits 6/8/1956     7,200
31-1E-4baa 28-33 Wisconsinan terrace deposits 5/16/1944     250
31-1E-4bad 32-34 Wisconsinan terrace deposits 6/7/1956     280
31-1E-9abb2 35-40 Wisconsinan terrace deposits 6/6/1944     70
31-1E-10aaa1 25 Wisconsinan terrace deposits 8/27/1943 63   72
31-1E-10aaa2 25 Wisconsinan terrace deposits 7/5/1956     79
31-1E-11ada 25 Wisconsinan terrace deposits 8/26/1943 62   117
31-1E-11baa 41-43 Wisconsinan terrace deposits 6/12/1956     202
31-1E-11bbb 33-35 Alluvium 6/11/1956     930
31-1E-11bcc 34-36 Wisconsinan terrace deposits 6/11/1956     8,050
31-1E-11cbb 24 Wisconsinan terrace deposits 6/11/1956     2,900
31-1E-11cbc 14-16 Alluvium 7/5/1956     1,750
31-1E-12bbb 38-40 Wisconsinan terrace deposits 6/12/1956     64
31-1E-13bbb 35-40 Wisconsinan terrace deposits 5/15/1944     1,180
31-1E-14aaa 26-28 Alluvium 7/6/1956     262
31-1W-26add 33 Wellington Formation 7/26/1956   2,350 89

Well number Depth,
feet
Geologic
source
Date of
collection
Temperature
(deg. F)
Sulfate
(SO4)
Chloride
(Cl)
32-2E-1abd 15-17 Alluvium 6/28/1956     361
32-2E-1dcd 9-11 Alluvium 6/27/1956     550
32-2E-13aaa 34-36 Wisconsinan terrace deposits 6/22/1956     2,290
32-2E-13abb 35-37 Wisconsinan terrace deposits 6/27/1956     32,700
32-2E-13add1 25 Wisconsinan terrace deposits 8/21/1943 63   356
32-2E-13daa 36-39 Wisconsinan terrace deposits 6/22/1956     9,820
32-2E-13ddc 39-41 Wisconsinan terrace deposits 6/22/1956     374
32-2E-17acc 72.9 Wellington Formation 7/26/1956   1,630 394
32-2E-22aaa 40 Illinoisan or Kansan terrace deposits 7/26/1956   15 10
32-2E-24aaa 45-47 Wisconsinan terrace deposits 6/22/1956     237
32-2E-24bcd   Wisconsinan terrace deposits 8/16/1956   56 8,540
32-2E-25abb 37-39 Alluvium 6/26/1956     18,700
32-2E-25ddd 30-32 Alluvium 9/13/1955     1,160
32-2E-31cdc 44.0 Illinoisan or Kansan terrace deposits 8/16/1956   1,800 770
32-1E-8ddd 49.4 Wellington Formation 6/26/1956   2,620 755
32-1E-9ddc 37.4 Wellington Formation 6/26/1956   130 183
32-1E-12dcc   Wellington Formation 6/26/1956   2,270 333
32-1E-16aaa   Wellington Formation 6/26/1956   2,470 810
32-4W-20ddd 37.4 Wisconsinan terrace deposits 8/15/1956   348 60
33-2E-1cbb 87.2 Illinoisan or Kansan terrace deposits 7/26/1956   42 14
33-2E-23cdd 19-24 Wisconsinan terrace deposits 5/10/1944     65
33-2E-27cad 39 Wellington Formation 7/26/1956   1,688 281
33-2E-27cdc 66 Wellington Formation 7/26/1956   3,470 5,020
33-3W-14cbb 51 Wellington Formation 8/15/1956   1,940 505
33-3W-15add 60 Wellington Formation 8/15/1956   806 273
33-4W-3aaa 241.0 Ninnescah Shale 8/16/1956   2,180 5,640
35-2E-1aaa 85.9 Wellington Formation 8/10/1956   1,410 129
35-2E-2bdd1 84.8 Illinoisan or Kansan terrace deposits 8/10/1956   43 44
35-1E-4aaa 32.1 Wellington Formation 8/10/1956   2,540 535
35-2W-8aaa 31.0 Ninnescah Shale 8/10/1956   296 414

Table 8Analyses of water from streams in Sumner County, Kansas. Analyzed by H.A. Stoltenberg. Dissolved constituents given in parts per million.

Sample no. Source Date of
collection
Sulfate
(SO4)
Chloride
(Cl)
30-1E-1aaa Arkansas River 8/13/1956 115 231
30-1E-3bbb Cowskin Creek 8/13/1956 194 95
30-1E-32ddc Ninnescah River 8/14/1956 163 348
30-1E-33ddd Oxbow Lake 6/23/1956   66
30-2W-1aaa Ninnescah River 8/14/1956 70 500
31-2E-35bda Ninnescah River 8/14/1956 85 493
31-1E-11bcc Ninnescah River 8/14/1956 95 650
32-2E-12dcc Arkansas River 7/11/1956 157 555
32-2E-14daa Stream 7/26/1956   8,130
32-1E-32cbc Slate Creek 7/26/1956 102 81
33-2E-15ccc Slate Creek 7/26/1956 842 4,010
33-2E-23dad Slate Creek 7/26/1956 1,890 13,700
34-2E-1dda Salt Creek 7/26/1956 3,220 19,800
34-2E-2cbc Salt Creek 7/26/1956 798 124
34-2E-23bcc Ditch 7/11/1956   71,400

Table 9--Factors for converting parts per million of mineral constituents to equivalents per million.

Cation Conversion factor   Anion Conversion factor
Ca++ 0.0499   HCO3- 0.0164
Mg++ 0.0822   SO4-- 0.0208
Na+ 0.0435   Cl- 0.0282
      NO3- 0.0161
      F- 0.0526

Chemical Constituents in Relation to Use

The following discussion of the chemical constituents of ground water has been adapted in part from publications of the U.S. Geological Survey and the State Geological Survey of Kansas.

Dissolved solids

When water is evaporated, the residue consists mainly of the mineral constituents listed in the tables of analyses, but generally includes a small quantity of organic material and some water of crystallization. Water containing less than 500 ppm of dissolved solids is satisfactory for domestic use except for difficulties resulting from its hardness or excessive iron content. Water containing more than 1,000 ppm is likely to include enough of certain constituents to cause a noticeably poor taste or to make the water unsuitable in some other respect.

The dissolved solids in 67 samples of ground water from Sumner County ranged from 146 to 158,400 ppm. Of these, 34 samples contained less than 500 ppm, 21 samples contained 500 to 1,000 ppm, and 12 samples contained more than 1,000 ppm. Strong concentrations of dissolved solids in water from unconsolidated aquifers in the county are probably due to contamination by brines.

Hardness

The hardness of water is recognized most commonly by its effects when soap is used with the water. Calcium and magnesium cause almost all the hardness of ordinary water and are the active agents in the formation of most of the scale in steam boilers and other vessels used to heat or evaporate water.

In addition to the total hardness, the carbonate and noncarbonate hardness are listed in the table of analyses. The carbonate hardness is due to the presence of calcium and magnesium bicarbonates and can be removed almost completely by boiling. This type of hardness is sometimes called "temporary" hardness as compared to "permanent" or noncarbonate hardness due to the presence of sulfates or chlorides of calcium and magnesium, which cannot be removed by boiling. With reference to soap consumption, the carbonate and the noncarbonate hardness do not differ. In general, water of noncarbonate hardness forms harder scale in steam boilers.

Water having a hardness of less than 50 ppm is generally rated as soft, and softening treatment is not necessary under ordinary circumstances. Hardness of 50 to 150 ppm does not interfere seriously with the use of water for most purposes, but it does increase the amount of soap used, and its removal is profitable for laundries and certain other industries. Water having a hardness in the upper part of this range will cause considerable scale in steam boilers. Hardness exceeding 150 ppm is very noticeable, and if the hardness is 200 to 300 ppm, water for household use is commonly softened. Where municipal water supplies are softened, an attempt generally is made to reduce the hardness to about 80 ppm. Additional improvement by further softening of a public supply generally is not deemed worth the increased cost.

The total hardness of 71 samples of ground water from Sumner County ranged from 54 to 8,800 ppm. Of these, 6 samples had less than 150 ppm, 21 samples had 150 to 300 ppm, and 41 samples had more than 300 ppm. Total hardness concentrations in excess of about 2,000 ppm are probably due to contamination of ground water by brine. Thirty-six samples contained less than 50 ppm of non-carbonate hardness and could be softened considerably by boiling.

Chloride

Chloride salts are found in nature in great abundance. They occur in sea water, in oil-field brines, in beds of nearly pure salt, and, in small quantities, in other types of rock. Concentrations of chloride salts in water can be readily recognized by the salty taste, but chloride content has little effect on the suitability of water for domestic use unless present in excessive quantity. Water containing much chloride may be corrosive if used in steam boilers. The removal of the chloride ion by present methods is too expensive to be practical. Most persons cannot detect a salty taste if chloride concentration is less than 500 ppm and can drink water containing as much as 2,000 ppm of chloride. Some livestock may survive on water containing as much as 10,000 ppm, but it has been recommended that, for their best production, stock should have water of a quality satisfactory for human consumption.

Analyses were made of 219 samples of water from wells and test holes in Sumner County to determine chloride content. The range was from 60 to 160,000 ppm: 170 of the samples had less than 500 ppm, 20 samples contained 500 to 2,000 ppm, 11 contained 2,001 to 10,000 ppm, and 18 contained more than 10,000 ppm. The distribution of chloride in water in Sumner County is shown in Plate 4. Chloride concentration in excess of about 5,000 ppm is probably due to contamination by brine. The concentration of chloride in the area west of Belle Plaine is probably due to natural pollution; that in the Oxford area, to contamination by oil-field brine.

The chloride content of 15 samples of surface water in Sumner County ranged from 66 to 71,400 ppm. Sample 32-2E-14daa was taken from a small stream near the center of the east side of sec. 14. The chloride concentration of this sample (8,130 ppm) was due chiefly to brine from three poorly plugged oil wells near the intersection of the two railroads in sec. 14. This condition will continue until the flow of salt water is stopped by proper plugging of these wells. Sample 34-2E-23bcc was taken from a small stream near the center of the west side of sec. 23. The concentration of chloride (71,400 ppm) in this sample came from several nearby abandoned oil-field brine ponds. Salt-water seepage can be expected to continue for several years in this area because the surface material surrounding the brine ponds is saturated with salt water. In August 1956 the chloride content of Arkansas River was found to increase downstream from 231 ppm west of Mulvane (sample 30-1E-1aaa) to 555 ppm at Oxford (sample 32-2E-12dcc). This increase in chloride is due to the movement of brine-contaminated ground water into the river from the Churchill oil field northeast of Oxford. A sample taken from Cowskin Creek, which carries much less sewage and industrial waste than Arkansas River, contained only 95 ppm of chloride (sample 30-1E-3bbb) as compared to 231 ppm chloride in a sample from Arkansas River in the same general area (sample 30-1E-1aaa). The chloride content of samples of water from Slate Creek increased greatly downstream from Wellington. Sample 32-1E-32cbc contained only 81 ppm of chloride, sample 33-2E-15ccc contained 4,010 ppm, and sample 33-2E-23dad contained 13,700 ppm. This increase in chloride content occurs where Slate Creek flows over that part of the Wellington Formation from which most of the Hutchinson Salt member has been removed by solution. Sample 34-2E-2cbc, from Salt Creek, contained 124 ppm, and sample 34-2E-1dda, taken from Salt Creek 2 miles farther east, contained 19,800 ppm chloride. This increase also is due to solution of salt from the Wellington Formation.

Iron

If a water contains more than a few tenths of a part per million of iron, it may have a disagreeable taste and will stain cooking utensils and plumbing. Upon exposure to air, most of the iron will settle out of the water as a reddish precipitate. The usual treatment of water to remove iron is aeration and filtration, but some water requires the addition of lime or some other substance. The quantity of iron in ground water may differ greatly from place to place although the water may be derived from the same formation. Iron carbonate is especially troublesome in water from the alluvial deposits of Ninnescah River.

The iron content of 67 samples of ground water from Sumner County ranged from 0 to 18 ppm. In 27 samples it was less than 0.11 ppm; 33 samples contained 0.11 to 2.0 ppm, and 7 contained more than 2.0 ppm.

Sulfate

Sulfate (SO4) in ground water is derived principally from gypsum (hydrous calcium sulfate) and from the oxidation of pyrite (iron disulfide). Magnesium sulfate (Epsom salts) and sodium sulfate (Glauber's salts), if present in sufficient quantity, will impart a bitter taste to the water and may have a laxative effect upon persons who are not accustomed to drinking such water. According to the U.S. Public Health Service (1946), sulfate in water supplies used on interstate carriers preferably should not exceed 250 ppm.

The sulfate content of 95 samples of ground water from Sumner County ranged from 3.7 to 7,800 ppm. In 30 samples it was less than 50 ppm; 36 contained 50 to 250 ppm, 8 contained 251 to 1,000 ppm, and 21 contained more than 1,000 ppm. The sulfate content of 12 samples of water from streams in Sumner County ranged from 70 to 3,220 ppm.

Fluoride

The fluoride content of drinking water is associated with the dental defect known as mottled enamel. Mottled enamel may appear on the teeth of children who, during the period of formation of the permanent teeth, customarily drink water containing fluoride in excess of 1.5 ppm. Concentrations of fluoride of about 1 ppm are known to prevent or lessen the incidence of tooth decay (Dean, 1938), and fluoride is now being added to many municipal supplies.

The fluoride content of 70 samples of ground water from Sumner County ranged from 0.1 to 0.7 ppm.

Nitrate

The use of water containing an excessive amount of nitrate in the preparation of a baby's formula can cause cyanosis or oxygen starvation. Some authorities advocate that water containing more than 45 ppm of nitrate should not be used (Metzler and Stoltenberg, 1950). Water containing 90 ppm of nitrate generally is regarded as very dangerous to infants, and water containing 150 ppm may cause severe cyanosis. Cyanosis is not produced in adults and older children by such concentrations of nitrate. The source of nitrate in ground water is not known, and boiling of water containing excessive nitrate does not make it safe for use by infants. Therefore, only water that is known to have a low content of nitrate should be given to infants.

The nitrate content of 70 samples of ground water from Sumner County ranged from 0.7 to 230 ppm. In 62 samples it was less than 45 ppm; 4 contained 45 to 90 ppm, 2 contained 91 to 150 ppm, and 2 contained more than 150 ppm.

Water for Irrigation

This discussion of the suitability of water for irrigation is adapted from Agriculture Handbook 60, U.S. Department of Agriculture (U.S. Salinity Laboratory Staff, 1954).

The development and maintenance of successful irrigation projects involve not only the supplying of irrigation water to the land, but also the control of the salinity and alkali of the soil. Irrigation practices, drainage conditions, and quality of irrigation water are all involved in salinity and alkali control. Soil that was originally non-saline and non-alkaline may become unproductive if excessive soluble salts or exchangeable sodium are allowed to accumulate because of improper irrigation and soil management or inadequate drainage.

In areas of sufficient rainfall and ideal soil conditions, the soluble salts originally present in the soil or added to the soil with water are carried downward by the water and ultimately reach the water table. This process of dissolving and transporting soluble salts by downward movement through the soil is called leaching. If the amount of water applied to the soil is not in excess of the amount needed by plants, there will be no downward percolation below the root zone, and mineral matter will accumulate at that level. Likewise, impermeable soil zones near the surface can retard the downward movement of water and cause waterlogging of the soil and deposition of salts. Unless drainage is adequate, attempts at leaching may not be successful, because leaching requires the free passage of water through and away from the root zone.

The characteristics of an irrigation water that seem to be most important in determining its quality are (1) total concentration of soluble salts, (2) relative proportion of sodium to other cations (magnesium, calcium, and potassium), (3) concentration of boron or other elements that may be toxic, and (4) under some conditions, the bicarbonate concentration as related to the concentration of calcium plus magnesium.

For purposes of diagnosis and classification, the total concentration of soluble salts in irrigation water can be adequately expressed in terms of electrical conductivity. Electric conductivity is the measure of the ability of the inorganic salts in solution to conduct an electric current and is usually expressed in terms of micromhos per centimeter. The electrical conductivity can be determined accurately in the laboratory, or an approximation of the electrical conductivity can be obtained by multiplying the total equivalents per million of calcium, sodium, magnesium, and potassium by 100, or by dividing the total dissolved solids in parts per million by 0.64. In general, water having electrical conductivity of less than 750 micromhos per centimeter is satisfactory for irrigation insofar as salt content is concerned, although salt-sensitive crops such as strawberries, green beans, and red clover may be adversely affected by water having an electrical conductivity in the range of 250 to 750 micromhos per centimeter. Water in the range of 750 to 2,250 micromhos per centimeter is widely used, and satisfactory crop growth is obtained under good management and favorable drainage conditions, but saline conditions will develop if leaching and drainage are inadequate. Use of water having a conductivity greater than 2,250 micromhos per centimeter is rare, and very few instances can be cited where such water has been used successfully.

In the past the relative proportion of sodium to other cations in irrigation water usually has been expressed simply as the percent sodium. According to the U.S. Department of Agriculture, however, the relative activity of sodium ions in exchange reactions with soil is a much better measure of the suitability of water for irrigation. The sodium-adsorption ratio (SAR) may be determined by the formula

SAR is sodium divided by the square root of one half the (calcium and magnesium

where the ionic concentrations are expressed in equivalents per million. The sodium-adsorption ratio may be determined also by use of the nomogram shown in Figure 10.

Figure 10--Nomogram for determining value of sodium-adsorption ratio of irrigation water.

Graphical method of finding sodium-adsorption ratio by plotting sodium and calcium+magnesium values and connecting the line.

Figure 11--Diagram showing classification of typical waters of Sumner County for irrigation use.

all samples are low in alkali hazard; most are medium to high on salinity

In using the nomogram to determine the sodium-adsorption ratio of a water, the concentration of sodium expressed in equivalents per million is plotted on the left scale (A), and the concentration of calcium plus magnesium expressed in equivalents per million is plotted on the right scale (B). The point at which a line connecting these two points intersects the sodium-adsorption-ratio scale (C) indicates the sodium-adsorption ratio of the water. When the sodium-adsorption ratio and the electrical conductivity of a water are known, the suitability of the water for irrigation can be determined by plotting these values on the diagram shown in Figure 11. Low-sodium water (S1) can be used for irrigation on almost all soils with little danger of developing harmful levels of exchangeable sodium. Medium-sodium water (S2) will present an appreciable sodium hazard in certain fine-textured soils, especially under poor leaching conditions. This water may be safely used on coarse-textured or organic soils having good permeability. High-sodium water (S3) may produce harmful levels of exchangeable sodium in most soils and will require special soil management such as good drainage, thorough leaching, and additions of organic matter. Very high sodium water (S4) is generally unsatisfactory for irrigation unless special action is taken, such as addition of gypsum to the soil.

Water of low salinity (C1) can be used for irrigation of most crops on most soils with little likelihood that soil salinity will develop. Water of medium salinity (C2) can be used if a moderate amount of leaching occurs. Crops having moderate salt tolerances, such as potatoes, corn, wheat, oats, and alfalfa, can be irrigated with C2 water without special practices. Water of high salinity (C3) cannot be used on soils having restricted drainage. Water of very high salinity (C4) can be used only on certain crops and then only if special practices are followed.

Boron is essential to normal plant growth, although the quantity required is very small. Crops vary greatly in their boron tolerances, but in general it may be said that the ordinary field crops common to Kansas are not adversely affected by boron concentrations of less than 1 ppm.

Prolonged use, under adverse conditions, of water having a strong concentration of bicarbonate could have an undesirable effect upon the soil texture and plant growth.

Of the 67 samples of ground water from Sumner County that were classified as to suitability for irrigation use, 9 (Table 10) were of such poor quality that they could not be plotted on Figure 11. All samples plotted had a low sodium hazard, but one sample had a very high salinity hazard and could be used for irrigation only under special conditions; 23 samples had a high salinity hazard, but could be used for irrigating most field crops on soils having adequate drainage; 32 samples had a medium salinity hazard and could be used for irrigation with no special practices on most soils, and 2 samples had a low salinity hazard and could be used to irrigate any crop on all types of soil.

Table 10--Classification of water in Sumner County for irrigation use.

Well number Approximate
conductivity,
(micromhos/cm)
Approximate
sodium-adsorption
ratio
Class
30-2E-6acd 1,670 4.0 C3-S1
30-2E-8bbb 1,500 1.3 C3-S1
30-2E-12cdc 1,010 1.0 C3-S1
30-2E-16ccc1 1,480 0.3 C3-S1
30-2E-18cdd 625 0.2 C2-S1
30-2E-20abb 1,040 1.1 C3-S1
30-2E-31bbb 550 0.6 C2-S1
30-1E-1bbb 930 1.5 C3-S1
30-1E-2aab1 630 1.4 C2-S1
30-1E-13ddc1 620 1.1 C2-S1
30-1E-15cdc 430 1.1 C2-S1
30-1E-16bba 510 1.7 C2-S1
30-1E-17bab 390 1.6 C2-S1
30-1E-25bcc 470 1.3 C2-S1
30-1E-36caa 490 1.7 C2-S1
30-1W-2ddd 670 0.6 C2-S1
30-1W-3bab 720 0.7 C2-S1
30-2W-22ada 5,250    
30-3W-33dcc 320 0.8 C2-S1
30-4W-16ccb 300 0.8 C2-S1
31-2E-2bba 630 0.6 C2-S1
31-2E-7cbc 570 0.4 C2-S1
31-2E-8bbb 670 1.2 C2-S1
31-2E-10dcc 550 0.2 C2-S1
31-2E-11dcd 800 0.4 C3-S1
31-2E-25bbc 2,370 0.8 CC4
31-2E-28aab 1,020 0.6 C3-S1
31-2E-29cbb 540 0.8 C2-S1
31-1E-3abb 247,500    
31-1E-4bbb 710 1.3 C2-S1
31-1E-4bdc1 980 2.2 C3-S1
31-1E-4bdc2 1,320 3.8 C3-S1
31-1E-5aba 490 0.1 C2-S1
31-1E-25bba1 640 1.9 C2-S1
31-1W-24bcb 4,190    
31-3W-5acd1 230 0.9 C1-S1
31-3W-23baa 490 0.6 C2-S1
31-4W-12bbd1 230 0.9 C1-S1
32-2E-14bbb1 700 1.4 C2-S1
32-2E-36abb 680 1.2 C2-S1
32-2W-20ddd 1,890 4.4 C3-S1
32-3W-11bbb 4,180    
32-3W-25ccb 670 1.6 C2-S1
32-4W-5abb 345 1.0 C2-S1
32-4W-9cc4 460 1.0 C2-S1
32-4W-20add 420 0.3 C2-S1
33-2E-6bba 4,260    
33-2E-25bbb 790 0.8 C3-S1
33-2E-26bdd 9,600    
33-2W-14ccd 790 2.0 C3-S1
33-3W-11bab 4,260    
33-3W-18baa 620 1.7 C2-S1
34-2E-2baa 4,270    
34-2E-17ccc 1,350 2.0 C3-S1
34-1E-32bdd 3,540    
34-1W-25ddb 790 0.8 C3-S1
34-1W-26aaa 880 1.3 C3-S1
34-2W-4bba 1,050 2.0 C3-S1
34-2W-21add 620 0.8 C2-S1
34-3W-31cdc 580 1.6 C2-S1
34-3W-35bac 865 1.5 C3-S1
34-4W-18aaa 820 3.1 C3-S1
35-1W-15ddb 895 2.2 C3-S1
35-2W-13dcc1 700 1.6 C2-S1
35-3W-11dca 800 0.8 C3-S1
35-3W-17aad 1,160 3.2 C3-S1
35-4W-8ccd 1,160 4.2 C3-S1

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Kansas Geological Survey, Geology
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