Ground Water, Continued
Quality of Water
The chemical character of the ground water utilized in Seward County is shown by the 20 analyses of water listed in Table 9. All samples, except those of wells 63 and 130, were collected by Frank E. Byrne during August 1940. The other two samples were collected from public-supply wells at Kismet and Liberal by the Kansas State Board of Health earlier in the same year. The analyses were made by Robert H. Hess, then chemist in the Water and Sewage Laboratory of the Kansas State Board of Health. The analyses, in general, do not indicate the sanitary condition of the waters as they show only the dissolved mineral contents. The constituents listed were determined by the methods used by the U. S. Geological Survey.
Chemical Constituents in Relation to Use
The following discussion of the chemical constituents of ground water in relation to use was adapted from publications of the U. S. Geological Survey.
Dissolved solids--When water is evaporated the residue consists mainly of the mineral constituents listed in Table 9 and generally includes a small quantity of organic material and a little water of crystallization. Waters containing less than 500 parts per million of dissolved solids generally are entirely satisfactory for domestic use, except for difficulties resulting from their hardness or occasional excessive content of iron. Waters containing more than 1,000 parts per million are likely to include enough of certain constituents to produce a noticeable taste or to make the water unsuitable in some other respects.
The dissolved solids did not exceed 500 parts per million in any of the samples of water that were collected in Seward County. Consequently, all waters that were sampled can be considered suitable for most ordinary uses. Three of the samples of water (from wells 53, 102, and 146) contained between 400 and 500 parts per million of dissolved solids, 11 of the samples contained between 300 and 400 parts per million, and the 6 samples contained between 200 and 300 parts per million.
Hardness--The hardness of water, which is the property that receives the most attention as a general rule, is most commonly recognized by its effects when soap is used with the water in washing. Calcium and magnesium cause almost all the hardness of ordinary water. These constituents are also the active agents in the formation of the greater part of all the scale formed in steam boilers and in other vessels in which water is heated or evaporated.
In addition to the total hardness, the table of analyses shows the carbonate hardness and the non-carbonate hardness. The carbonate hardness is that due to the presence of calcium and magnesium hi-carbonates and can be almost entirely removed by boiling, in some reports this type of hardness is called temporary hardness. The non-carbonate hardness is due to the presence of sulfates or chlorides of calcium and magnesium; it cannot be removed by boiling and has sometimes been called permanent hardness. With reference to use with soaps, there is no difference between the carbonate and non-carbonate hardness. In general, the non-carbonate hardness forms harder scale in steam boilers.
Water having a hardness of less than 50 parts per million generally is rated as soft, and its treatment for the removal of hardness under ordinary circumstances is not necessary. Hardness between 50 and 150 parts per million does not seriously interfere with the use of water for most purposes; however, it does slightly increase the consumption of soap, and its removal by a softening process is profitable for laundries or other industries using large quantities of soap. Waters in the upper part of this range of hardness will cause considerable scale on steam boilers. Hardness above 150 parts per million can be noticed by anyone, and if the hardness is 200 or 300 parts per million it is common practice in some areas to soften water for household use or to install cisterns to collect soft rain water. Where municipal water supplies are softened, an attempt is generally made to reduce the hardness to 60 or 80 parts per million. The additional improvement from further softening of a whole public supply is not deemed worth the increase in cost.
The range in hardness in the water samples from Seward County was from 258 to 480 parts per million. The supplies for Kismet (389 parts per million) and Liberal (338 parts per million) are not softened before being discharged into the mains but may be softened in the home or in industry before consumption. All waters used in the locomotives of the Chicago, Rock Island, and Pacific Railway Company are treated before use.
Iron--Next to hardness, iron is the constituent of natural waters that in general receives the most attention. The quantity of iron in ground waters may differ greatly from place to place, even though the waters are derived from the same formation. If water contains much more than 0.1 part per million of iron, the excess may be present in sufficient quantity to give a disagreeable taste and to stain cooking utensils. Iron may be removed from most waters by simple aeration and filtration but a few waters require the addition of lime or some other substance.
Two of the water samples collected from wells in Seward County contained no iron (22 and 100). Five wells (23, 53, 102, 130, and 156) yielded water containing less than 0.1 part per million of iron and nine samples (8, 24, 31, 63, 69, 78, 96, 113, and 118) contained more than 0.1 part per million but less than 1.0 part per million. Samples taken from wells 105, 113, 141, and 146 contained 1.0 part per million or more of iron. The iron content of the water from well 141 was the highest of all those sampled, 1.9 parts per million.
Fluoride--Although determinable quantities of fluoride are not so common as fairly large quantities of the other constituents of natural water, it is desirable to know the amount of fluoride present in water that is likely to be used by children. Fluoride in water has been shown to be associated with the dental defect known as mottled enamel, which may appear on the teeth of children who, during the period of formation of the permanent teeth, drink water containing fluoride. It has been stated that waters containing one part per million or more of fluoride are likely to produce mottled enamel, although the effect of one part 'per million is not usually very serious (Dean, 1936). If the water contains as much as four parts per million of fluoride, 90 percent of the children drinking the water are likely to have mottled enamel, and 35 percent or more of the cases will be classified as moderate or worse. Small quantities of fluoride, not sufficient to cause mottled enamel, are likely to be beneficial by decreasing dental caries (Dean, Arnold, and Elvove, 1942).
Only two of the water samples collected in Seward County contained fluoride in excess of one part per million. Well 53 contained 1.2 parts per million of fluoride and 156 contained 3.0 parts per million.
Water for irrigation--The suitability of water for use in irrigation is commonly believed to depend mainly on the total quantity of soluble salts and on the ratio of the quantity of sodium to the total quantity of sodium, calcium, and magnesium. The quantity of chloride may be large enough to affect the use of the water and in some areas other constituents, such as boron, may be present in sufficient quantity to cause difficulty. In a discussion of the interpretation of analyses with reference to irrigation in southern California, Scofield (1933) states that if the total concentration of dissolved salts is less than 700 parts per million there is not much probability of harmful effects in irrigation use. If it exceeds 2,100 parts per million, there is a strong probability of damage to either the crops or the land, or both. Water containing less than 50 percent sodium (the percentage being calculated as 100 times the ratio of the sodium to the total bases, in equivalents) is not likely to be injurious, but if it contains more than 60 percent its use is inadvisable. Similarly, a chloride content less than 142 parts per million is not objectionable, but more than 355 parts per million is undesirable. It is recognized that the harmfulness of irrigation water is so dependent on the nature of the land and the crops, on the manner of use, and on the drainage that no definite limits can be adopted.
The mineral content of the samples of water collected in Seward County did not exceed any of the limits of suitability for irrigation as determined by Scofield; hence, ground water from any part of Seward County probably would be suitable for irrigation.
The analyses of water given in Table 9 show only the amounts of dissolved mineral matter in the water and do not indicate the sanitary quality of the water. An abnormal amount of certain mineral matter, such as nitrate, however, may indicate pollution of the water.
About one-third of the prewar population of Seward County was dependent upon private water supplies from wells and every precaution should be taken to protect these supplies from pollution. A well should not be located where there are possible sources of pollution, such as barnyards, privies, and cesspools, and every well should be tightly sealed down to a level somewhat below that of the water table. As a general rule, dug wells are more subject to contamination from surface water than are drilled wells, chiefly because they generally are not effectively cased or sealed at the surface. Drilled wells generally are well protected by the casing, although many are poorly sealed at the top.
Quality of Water in Relation to Water-bearing Formations
The general character of water from the principal water-bearing formations in Seward County is indicated in Figure 9 and is discussed below.
Figure 9--Analyses of waters from the principal water-bearing formations in Seward County.
Pliocene and Pleistocene formations--The Laverne, Rexroad (?), and Meade formations yield water to most of the wells in Seward County. The Rexroad (?) is the principal water-bearing formation in the area because in most places the water table is near or below the base of the Meade formation and because ground water in the Laverne formation generally is not utilized owing to its. considerable depth. Because of the lithologic similarity of the coarse water-bearing materials in these formations and because a large number of wells probably obtain water from more than one formation, the quality of the water from the three formations will be discussed in one section.
Samples of water from these deposits ranged in hardness from 177 to 275 parts per million, the average being 231 parts per million. The amount of dissolved solids ranged from 258 to 480 parts per million and averaged 333 parts per million. The average fluoride content of these waters was 0.7 parts per million.
Alluvium--Water from the Recent alluvium of Cimarron River is generally of poorer quality than that from the water-bearing formations mentioned above. Three samples of water were collected from wells ending in these deposits. The average hardness of these waters was 259 parts per million. The amount of dissolved solids averaged 396 parts per million and the fluoride content averaged 0.9 part per million.
Kansas Geological Survey, Geohydrology
Web version Sept. 2001. Original publication date March 1948.
Comments to email@example.com
The URL for this page is http://www.kgs.ku.edu/General/Geology/Seward/05_gw7.html