The chemical character of the ground waters in Meade County is shown by the analyses given in table 7. The analyses were made by Robert H. Hess and Elza O. Holmes in the Water and Sewage Laboratory of the Kansas State Board of Health. Forty-four samples of water were collected from representative wells in all parts of the county but mainly from wells in the Meade artesian basin. Most of the wells sampled derived their water from the Ogallala or Meade formations or from alluvium, but a few of the wells, tapped the Permian, Laverne, and Kingsdown formations. In addition, three samples of surface water (A, B, and C) were collected, and analyses of water pumped for public supplies at Fowler, Meade, and Plains have been supplied by the State Board of Health.
The fluoride content of the waters was determined by the Modified Sanchis method, and the other constituents given 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 has been adapted from publications of the United States Geological Survey.
Total dissolved solids--The residue left after a natural water has evaporated consists of rock materials with which may be included some organic material and a little water of crystallization. Waters with less than 500 parts per million of dissolved solids generally are entirely satisfactory for domestic use, except for the difficulties resulting from their hardness and, in some areas because of excessive iron corrosiveness. Waters having more than 1,000 parts per million are likely to contain enough of certain constituents to produce a noticeable taste or to make the water unsuitable in some other respects.
The concentration of total dissolved solids in well waters collected in Meade County ranged from 190 to 2,169 parts per million. The waters from all but five of the wells contained less than 500 parts per million of dissolved solids, however, and are suitable for most ordinary purposes. Five wells yielded waters containing between 500 and 1,000 parts per million of dissolved solids, and the water from one well (160) contained more than 1,000 parts.
Hardness--The hardness of water is the property that generally receives the most attention, and it is commonly recognized by its effects when soap is used with the water in washing. Calcium and magnesium cause practically all the hardness of ordinary waters. 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 noncarbonate hardness. The carbonate hardness is that due to the presence of calcium and magnesium bicarbonates. It is removed almost completely by boiling. In some reports this type of hardness is called temporary hardness. The noncarbonate hardness is due to the presence of sulphates or chlorides of calcium and magnesium, but it can not be removed by boiling and has sometimes been called permanent hardness. With reference to use with soap, there is no difference between the carbonate and noncarbonate hardness. In general, the noncarbonate hardness forms harder scale in steam boilers.
Water having a hardness of less than 50 parts per million is generally rated as soft, and its treatment for 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, but 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 in steam boilers. Hardness of more than 150 parts per million can be noticed by anyone, and if the hardness is 200 or 300 parts per million it is common practice to soften water for household use or to install a cistern to collect soft rain water. Where municipal water supplies are softened, an attempt is generally made to reduce the hardness to from 60 to 80 parts per million. The additional improvement from further softening of a whole public supply is not deemed worth the increase in cost.
The hardness of the samples of well water from Meade County ranged from 128 to 898 parts per million. The softest water analyzed was from well 291 in the Ogallala and Permian, and the hardest water obtained was from well 160 in alluvium and Kingsdown. Of the 50 samples analyzed 47 percent had a hardness between 100 and 200 parts per million, 36 percent had from 200 to 300 parts, and 11 percent had from 300 to 400 parts. Only 6 percent of the samples had a hardness in excess of 400 parts per million.
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 from the same formation. If a water contains much more than 0.1 part per million of iron, the excess may separate out and settle as a reddish sediment. Iron, which may be present in sufficient quantity to give a disagreeable taste and to stain cooking utensils, may be removed from most waters by simple aeration and filtration, but a few waters require the addition of lime or some other substance.
Most of the water from wells in Meade County contained more than 0.1 part per million of iron. Five samples contained between 1.0 and 2.0 parts per million of iron, and seven samples contained more than 2.0 parts. The water from well 333 had the highest iron content (8 parts per million) of the waters analyzed.
Fluoride--Although determinable quantities of fluoride are not so common as fairly large quantities of the other constituents of natural waters, it is desirable to know the amount of fluoride present in waters that are 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 drink water containing fluoride during the period of formation of the permanent teeth. It has been stated that waters containing 1 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, 1935, pp. 1,269-1,272). If the water contains as much as 4 parts per million fluoride, 90 percent of the children exposed are likely to have mottled enamel and 35 percent or more of the cases will be classified as moderate or worse.
Less than 1 part per million of fluoride was determined in 76 percent of the samples collected from Meade County, and the remaining 24 percent contained from 1 to 2 parts. The maximum fluoride content of 2.0 parts per million was found in a sample of water from well 291.
Water for irrigation--The suitability of water for use in irrigation is commonly held 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 together. 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) suggested 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; but, 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 of 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, the crops, the manner of use, and the drainage that no hard and fast limits can be adopted.
All but four of the samples of water collected in Meade County are well within the limits suggested by Scofield for safe waters for use in irrigation. Water from wells 276, 291, and 299 contained respectively 702, 816, and 827 parts per million of dissolved solids. Well 160 contained 2,169 parts per million of dissolved solids and probably would not be suitable for irrigation.
The analyses of water given in table 7 show only the amounts of dissolved mineral matter in the water and do not indicate the sanitary quality of the water.
More than 50 percent of the population of Meade County is dependent on 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 nor where surface water can descend to the water table. Every well should be constructed so as to seal off all surface water. As a general rule, dug wells are more subject to contamination from surface water than are drilled wells, owing mainly to the fact that generally they are not effectively sealed at the surface. More than 95 percent of the wells in Meade County are drilled wells.
Relation to Stratigraphy and Structure
The quality of ground waters in Meade County is closely related to the deposits from which the water is obtained, and, to a lesser extent, to the structure of these deposits. The influence of structure on the quality of the water is shown by the relatively high chloride content of ground water along the Crooked Creek and Fowler faults. The waters from wells 160, 191, and 199 contained respectively 325, 289, and 315 parts per million of chloride. Such concentrations of chloride are unusually high for this county and probably were caused by brines migrating upward along the fault zones from the underlying Permian rocks.
The typical quality of water in the five principal water-bearing formations in Meade County is shown in figure 11, and is discussed below.
The range in concentration of significant mineral constituents in waters from the four principal water-bearing formations in Meade County is given in table 8. Owing to the fact that only one unmixed sample of water from the Permian redbeds was analyzed (fig. 11), it was not included in this table. Also waters from the Kingsdown silt and from the alluvium are considered together. With this exception, only unmixed samples of water are included in the table.
Table 8--Range in concentration of total dissolved solids, hardness, fluoride, and iron in water from the four principal water-bearing formations of Meade county, in parts per million.
|Fluoride (F)||Iron (Fe)|
|Kingsdown silt and alluvium||6||2,169||354||898||220||1.5||0.7||7.1||*|
* Less than 0.15 part
Permian redbeds--Water is pumped from Permian rocks only in the southeastern part of the county. The water contains a large amount of calcium and sulphate and therefore, generally, is excessively hard. These beds are cemented by iron oxide, but the water has a low iron content because iron present as the ferric oxide is relatively insoluble.
Ogallala formation--The Ogallala formation on the whole yields water of better quality than the other water-bearing formations in Meade County. The total dissolved solids and total hardness of the Ogallala waters are appreciably lower than in the waters from the Kingsdown silt and alluvium and somewhat lower than in those from the Meade formation. Although there is but slight difference in the iron and fluoride content of the various waters, the Ogallala waters compare favorably with the others.
Meade formation--On the basis of only seven analyses, it appears that the Meade waters are only slightly higher in total solids and hardness than the Ogallala waters. In general, the quality of water from the Meade formation is somewhat inferior to that from the Ogallala formation.
Kingsdown silt and alluvium--The quality of waters from the Kingsdown silt and from the alluvium shows the greatest range of any ground waters in the county. The total solids and hardness of waters from these formations in general are considerably higher than waters from either the Ogallala or Meade formations. The iron and fluoride content of waters from the Kingsdown and the alluvium is approximately the same as in waters from the Ogallala and compares favorably with waters from the Meade formation.
Kansas Geological Survey, Geologic History of Kansas
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Web version February 2004. Original publication date Dec. 1942.