Moyle, John B.

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Journal of the Minnesota Academy of Science Volume 13 Number 1 Article 3 4-1945 Classification of Lake Waters Upon the Basis of Hardness John B. Moyle Follow this and additional works at: https://digitalcommons.morris.umn.edu/jmas  Part of the Hydrology Commons Recommended Citation Moyle, J. B. (1945). Classification of Lake Waters Upon the Basis of Hardness. Journal of the Minnesota Academy of Science, Vol. 13 No.1, 8-12. Retrieved from https://digitalcommons.morris.umn.edu/jmas/vol13/iss1/3 This Article is brought to you for free and open access by the Journals at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Journal of the Minnesota Academy of Science by an authorized editor of University of Minnesota Morris Digital Well. For more information, please contact skulann@morris.umn.edu. 8 THE :MINNESOTA ACADEMY OF SCIENCE groups Q to 7 was 58, 45, 83, 96, 83 and 86 per cent of the amount entering similar muscle of normal animals. The amount entering the muscle which had been previously occluded in each of these groups was 96, 83, 169, 224, 162 and 134 per cent of the normal calculated on a basis of dry weight of muscle. Considerable eleva-tion of the phosphate content of the plasma occurred in groups 4, 5, 6 and 7. If the elevated phosphate of the plasma is considered it appears that the unoccluded muscle is much less permeable to plasma phosphate than normal and that the muscle previously oc-cluded is permeable about as much as normal except in groups 6 and 7 when the blood pressure was greatly reduced. CLASSIFICATION OF LAKE WATERS UPON THE BASIS OF HARDNESS JOHN B. MOYLE Division of Game and Fish Chemically, hardness is a measure of the soap-consuming power of water. Calcium, magnesium, and to a lesser extent iron and aluminum are the principal metals which in fresh waters form in-soluble compounds with soap. The amount of soap used before suds are formed can be taken as an index of the total concentration of these metais. Although water hardness is of two types, temporary hardness due to carbonate salts and permanent hardness due to sulphate salts, hardness is always expressed as parts per million of calcium carbonate. Temporary hardness is so called because heating the water precipitates the disolved carbonates as scale. Sulphate salts which cause permanent hardness are not affected by heating. From the point of view of utilization for public and industrial water supply, Theroux, Eldridge and Mallman (1943) classify waters as follows: Sufficiently soft for ordinary use Moderately hard Hardness noticeable to most persons ,v a ter softeners often necessary Total hardness expressed as p.p.m. calcimn carbonate Less than 50 to 75 p.p.m. 75 to 100 p.p.m. Greater than 150 p.p.m. Greater than 200 p.p.m: Since this classification is designed primarily for the use of water supply engineers, it is of limited value t9 workers in the fields of limnology and fisheries. It has long been recognized that hard .carbonate, waters are often more productive of aquatic life than soft carbonate waters, and because of this several schemes have been devised by biological workers for the classification of waters upon the basis of hardness. It should be remembered that in most fresh waters the concentra-PROCEEDINGS, VOLUME THIRTEEN, 1945 tion of sulphate salts is low and that the 'term "hardness" as em-ployed by many limnological and fisheries workers refers to carbonate or temporary hardness and is often regarded as practically synony-mous with total alkalinity (methyl orange alkalinity) or bound carbon dioxide. Birge and Juday (1911) classified Wisconsin lake -waters on the basis of hardness as follows: Soft-water lakes Median class lakes Hard-water lakes EX[Jressed M cc. bound. carbon dioxide per liter Less than 5 5 to 22 More than 22 Recalculated as p.p.m. calcium carbonate Less than 20.3 20.3 to 89.2 More than 89 .2 This is a natural classification which is valid in Minnesota waters but which is not complete enough to afford adequate description and coverage of all waters in the state. The classification of water hardness included in the Wildlife Handbook for the 'North Central Region (United States Depart-ment of Agriculture, 1940) seems to be a more or less arbitrary separation of waters for convenient and consistent description. It appears to have no biological basis. The scheme given in this hand-book is as follows: Very soft water Soft water Medium water Medium hard water Hard--water EX[Jressed M p.p.m. bound carbon dioxide 0-5 5-10 10~20 20-30 30 1 Recalculated M p.p.7n. calcium carbonate 0-11.4 11.4-22.7 22.7-45.5 45.5-68.2 68.2 Botanists have long recognized the existence of three aquatic floras whose distribution is related to tlie chemical quality of the water. They are (1) the acid or soft-water flora, (2) the calcareous or hard-water flora, and (3) the brackish or alkali-water flora. These floras have been variously delimited and classified by such workers as Metcalf (1931), Naumann (1932), Samuelsson (1934), McAt,ee (1939), Martin and Uhler (1939), and Coston, Pentelow and Butcher (1936). Extensive work 'on Minnesota lakes (Moyle, 1945) shows that the separation between these floras in Minnesota usually has the following chemical basis: Soft-water lakes Hard-water lakes Alkali or sulphate-Total, alkalinity as p.p.m. calcium carbonate Sulphate ion p.p.m. Less tha,n 5 Usually less than 10 water lakes More than 100 More than 50 Soft-water lakes are characterized by a scanty growth of larger aquatic plants and typically support such rosette- or tuft-forming 10 THE MINNESOTA ACADEMY OF SCIENCE species as water lobelia (Lobelia Dortmanna L.), pipewort (Erio-caulon septangulare With.), quill wort (Isoetes Braunii Dur.), floating leaf burreed (Sparganium fluctuans (Morong) Robinson), and sub-merged bulrush (Scirpus subterminalis Torr.). Other characteristic species are the little yellow water lily (Nuphar microphyllum (Pers.) Fern.), milfoil (Myriophyllum alterniflorum DC.), and the spiral pondweed (Potamogeton Spirillus Tuckerm.). Alkali or sulphate waters are ,characterized by brackish-water species especially wid-geon• grass (Ruppia occidentalis Wats.), spiny naiad (Najas marina L.), horned pondweed (Zannichellia palustris L.), and bayonet grass (Scirpus paludosus ·Nels.). The hard-water lakes support a robust growth of the common pondweeds (Potamogeton spp.), muskgrasses (Chara spp.), milfoil, coontail, waterlilies and many other aquatic plants. However, the typical alkali and soft-water plants are absent. If these botanical data are combined with other types of limno-logical and fisheries data for the Minnesota lakes, a more detailed classification of lake waters on the basis of hardness can be devised. The following proposed scheme is essentially a combination of the foregoing classification based upon distribution of aquatic plants with that of Birge and Juday (1911) and represents a natural ar-rangement for the chemical separation of Minnesota lake waters. Very soft-water lakes Soft-water lakes Medium hard-water lakes Hard-water lakes Medium alkali-water lakes Alkali-water lakes Total alkalinity as p.p.m. calcium carbonate 0-20 21-40 41-90 More than· 91 More than 100 More than 100 Sulphate ion p.p.m. Less than 5 Less than 5 Less than 5 Less than 50 50-125 More than 125 In regions generally low in sulphate salts the last two categories can be disregarded and since it appears from Minnesota fish pond pro-duction data that sulphates in low concentrations such as those of the first four categories have little if any effect on productivity, sulphate analyses are essential only where alkali waters may be expected to occur. The bases for the foregoing classifications are as follows: V enJ soft-water lakes. - General productivity low; larger aquatic plant growth sparse and that mostly limited to typical soft-water species; deep lakes are often trout water with oxygen below the thermocline; lakes generally unsuited to centrarchid fishes and wall-eye pike; plankton sparse; no blue-green algal bloom or free-floating vegetation, such as duckweeds, unless there is pollution. Unfertilized fish ponds with this type of water are usually not productive. Plants typical of this type of water are the rosette-forming species Lobelia Dortmanna, Eriocaulon septangulare, Isoetes Braunii and such slender species as Potamogeton Spirillus, Myriophyllum alterni-PROCEEDINGS, VOLUME THIRTEEN, 1945 11 fforum, and Nitella sp. The more robust submerged plants are no-ticeably absent. Sagittaria spp. frequently developed only juvenile leaves (phyllodes) in water of this type. Soft-water lakes. - General productivity fair to good; aquatic plants, especially pondweeds, more abundant than in preceding type; deep lakes usually have oxygen below the thermocline and often support a cisco or trout population; lakes of this type often have a good walleye pike population but in Minnesota are usually not productive of panfish; usually no blue-green algal bloom; free-floating aquatic plants are lacking or very rare; several fish ponds with waters .of this type have proven to be moderately productive. Typical plants are the soft-water species mentioned for the preced-ing group plus the more robust aquatic plants such as Potamoget"on amplifolius, P. alpinus, P. natans, P. epihydrus, Nuphar microphy-lum, and Vallisneria americana. Typical hard-water species such as Potamogeton pectinatus, P. Richardsonii, and Chara spp. are usually lacking or make poor growth. · Medium hard-water lakes. - General productivity good; some of the most productive Minnesota lakes fall in this category; larger aquatic plants abundant and robust, the larger potamogetons being the predominant members of the flora; typical soft-water species are absent; some waters in this category have summer oxygen depletion below thermocline, others do not and support tullibee populations; there are few trout lakes with water of this type but many good panfish and walleye pike waters; harder waters of this category often have moderate blue-green algal blooms and _free-floating vegetation is fairly common. Some of the more productive Minne-sota fish ponds have been those with medium hard waters. Typical plants of this water type are Nuphar variegatum, Nymphaea odo-rata, Potamogeton amplifolius, P. natans, P:, strictifolius, P. Rob-binsii, Bidens Beckii, Pontederia cordata; Eleocharis palustris var. major, as well as many other robust species more typical of harder waters. Hard-water lakes. - General productivity good; many of the best Minnesota walleye pike and panfish lakes are in this category; larger aquatic plants robust and abundant' but often limited to water less than 10 feet deep because of heavy plankton production; deep lakes usually have summer oxygen depletion below the t,hermo-cline; lakes often have a heavy blue-green algal bloom and free-floating plants such as duckweeds and Ceratophyllum'demersum are abundant. Many fish ponds with this type of water have produced well. Typical plants of this type of water are Potamogeton pectina-tus, P. Richm:dsonii,P. praelongus, Najas fiexilis, Chara spp., Cerato-phyllum demersum, Myriophyllum exalbescens, and Potamogeton -gramineus forma myriophyllus. Medium alkali~water lakes.-General productivity good; many good panfish lakes, some walleye lakes, and carp and bullhead waters fall in this category; larger aquatic plants are usually abun-12 THE MINNESOTA ACADEMY OF SCIENCE dant and robust and generally similar to the preceding water type except that some members of the alkali flora: appear; there are no deep lakes of this type in Minnesota and some are so shallow that winter oxygen depletion can usually be expected; a heavy blue-green algal bloom is usual in summer and duckweeds are often abundant in bays. The production of fish ponds with water of this type has been moderately good to good. Typical aquatic plants of waters of this type are Potamogeton pectinatus, P. Richardsonii, P. foliosus, Najas flexilis, Chara spp., with the typical alkali-water plants Rup-pia occidentalis, N ajas marina, and Zannichellia palustris. Alkali-water lakes. - General productivity good for lakes within the sulphate range found in Minnesota fishing waters (less than 300 p.p.m. of S04 ion); aquatic plant growth often heavy but of a few species compared to hard carbonate waters; there are no deep lakes of this type in Minnesota, all being shallow prairie lakes; summer blue-green algal blooms are common although small lakes with a very high sulphate concentration may remain clear; duckweeds and Ceratophyllum often abundant; most larger aquatic plants typical of hard carbonate waters grow poorly when the sulphate ion con-centration exceeds 300 parts per million; fish ponds with a sulphate ion concentration above 250 parts per million usually have not produced well. Typical plants are Ruppia occidentalis, Najas ma-rina, Zannichellia palustris, Potamogeton pectinatus, P. Richard-sonii, Najas flexilis, and Chara spp. Data from areas with waters having higher salt concentrations than those found in Minnesota (Metcalf, 1931) show that the vegetation becomes increasingly limited as the concentration of alkali salts increases. BIBLIOGRAPHY Birge, E. A. and C. Juday. The inland lakes of Wisconsin. The dissolved gases of the water and their biological significance. Wis. Geo!. Nat. Hist. Surv. Bull. 22, Sci. Ser. 7, 1911, 259 pp. Coston, H. E. T., F. T. K. Pentelow and R. W. Butcher. River management. The making, care and development of salmon and trout rivers. Lippincott Co., Phila-delphia, 1936, 263 pp. McAtee, W. L. Wildfowl food plants. Their value, propagation and managem'ent. Collegiate Press, Ames, Ia., 1939, 141 pp. Martin, A. C. and F. M. Uhler. Food of game ducks in the United States and Canada. U.S. Dept. Agr. Tech. Bull. No. 634, pp. 1 to 156, 1939. Metcalf, Franklin. 1931. Wild duck foods of North Dakota lakes. U. S. Dept. Agr. Tech. Bull. No. 221, pp. 1 to 72. 1931. Moyle, John B. 1945. Some chemical factors influencing the distribution of aquatic plants in Minnesota. Am. Mid. Nat. (in press). Naumann, Einar. Grundziige der regionalen Limnologie. Die Binnengewasser, 1932, Vol. 9, xiv + ·175 pp. Samuelsson, G. Die Verbreitung der hohere Wasserpflanzen in Nordeuropa (Fen-noskanien und Danemark). Acti:t Phytogeogrophica Succica, Vol. 6, pp. 1 to 211, 1934. Theroux, Frank R., Edward F. Eldridge, and W. Le Roy Mallmann. Laboratory manual for chemical and bacterial analyses of water and sewage. McGraw-Hill, 1943, X + 274 pp, United States Dept. Agriculture, Forest Service. Wildlife handbook. North Central Region. Mimeo. 

Classification of Lake Waters Upon the Basis of Hardness

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Classification of Lake Waters Upon the Basis of Hardness

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