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Show UNITED STATES DEPARTMENT OF AGRICULTURE Agricultural Research Administration Bureau of Plant Industry, Soils, and Agricultural Engineering Division of Rubldoux Laboratory, Soil Managenent and Irrigation Riverside, California October 1, I9U7 CHANGE IN METHOD OF REPORTING CONDUCTANCE DETERMINATIONS Effective October 1, 19^7. Rubidoux laboratory will report conductance determinations in terms of micromhos instead of mhos x 105 as in the past two abbreviations, identical in meaning, may be used. or EC, micromhos/cm © 25° C where EC is electrical conductivity and is synonymous with the term formerly used "specific electrical conductance". Certain relationships beiween KxlO5025°C and EOxlO6@B5°C follow: Kxio5©25°c multiplied by 10 equals ECxlO ©25°C The ratio Kxl0->©25oc/sum of anions equals approximately 10 The ratio ECxlO ©25°c/sum of anions equals approximately 100 / ^ o The ratio Dissolved Solids in p.p.m./KxlO ©25 C equals approximately 7 The ratio Dissolved Solids in p.p.m./ECxlO @25°C equals approximately 0.7 This ne77 method of reporting will not involve any change in the procedure for determining conductivity. The cell constant and resistance values will not be affected. The quotient obtained by dividing C by R gives the conductivity in mhos. This value was multiplied by 10-5 to give Kxlo5<925OC and this same value will be multiplied by 10bto give ECxlO°@25°C. The more important reasons for adopting the new unit relate to the need for a uniform and standard method of reporting. Conductivity data, other than for natural waters, almost without exception are reported in micromhos/cm and some agencies have used the unit for natural waters. Conferences, in Tfeshlngton this past summer, between a number of Federal Agencies resulted in the recommendation that all Federal Agencies report conductivity data in micromhos/cm. Tnis laboratory agreed to the proposal along with the U. S. Regional Salinity Laboratory, the U. S. Geological Survey Qiallty of Tfeter Branch, U. S. Bureau of Reclamation Research Laboratory at Denver, Fish and Wildlife and possibly others. L. V. tfilcox, Agronomist. |
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Original book: [State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants, United States of America, State of Nevada, State of New Mexico, State of Utah, interveners] : |