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Show GREAT SALT LAKE ' 500 YEARS AGO Investigation to Determine the Relative Annual Precipitation in the Great Salt Lake Drainage Area Before the Coming of White ( Race Important Data to Be Obtained. The present behavior and past history his-tory of Great Salt Lake is attracting more and more attention each year and is now the object of a special investigation in-vestigation by the I Tnite.l States geological geo-logical survev. The I'nit.d Stales weather bureau precipitation records, beginning in 1Mj'5. present a comparatively compar-atively accurate record of the levels of ('rent Salt Lake dating back to the jear In lS'.u the lake stood at U feet. In ISf.fc the water rose 10 II feet, dropped lo 7.5 feet in is?:;, and rose again to II t'e.t in 1S7T. The lake then gradually lowered until the water stood at 2.4 feet in H"2 and 2.2 leet in 1 '.'".". Since Kin." the water has gradually risen, reaching the J loot mark lit May l'JH'i. The lake is now falling. Many millions of dollars have been f-rcnt in the construction of railroads and reverts over or near the shores ( ol the Great Salt Lake. If any data i can b.- secured which will enable one to make a reliable prediction as In i the behavior of the lake ton years in i advance, the Information would be of . inestimable value. It will bo necessary neces-sary to delcimiiic whether or not there are regular periods nf wet and dry years: also to determine the lime intervening between two wet and two dry periods. To determine this point one should have precipitation records dating back one. hundred years or more Taking, for example, a forest for-est tree which is some distance Jto.n a flowing stream, and one which receives re-ceives no moisture from artificial sources, It is believed that the annual growth of this tree would bear a direct di-rect relation to the am. 'tint of precipitation pre-cipitation which Jell during the winter win-ter just prior to the growing season. The amount of growth made during each year may be determined by meas uririg the thickness of the tree's annular an-nular rings. The temperature during the growing season would have its effect ef-fect upon the growth of the tree, and i. is therefore not expected that the data obtained Horn measuring the thickness ol annulaiOings would give reliable records lor successive years where there is ilttle variation In tho annual precipitation. It seems reasonable reason-able to believe that the high normal 1'iul low years can b? determined. Tho forest service has extended it3 assistance in this Interesting Invest! gatiou by cutting a big tree from the Hig Cottonwood drainage urea, which lies ten miles southeast of Salt Lake City. This tree is be'ween four and five hundred years old A section will be cut ami polished in order that the thickness of the annular rings may be ca-iiv measured. A thorough study will be made of the first sixty annular rings and a comparison made with the sixty year record of the levels lev-els or Great Salt Luke if n definite relation can be detci mined, showing that a certain amount ui precipitation produces a ling of certain thickness, this relation can then be -applied back t i the tenter of the tree and an estimate esti-mate thereby secured for the annual precipitation for a period of four hun drd to five hundred years. An effort will be made to complete this study I during the next three months. |
