TY - Generic T1 - Effect upon seasonal runoff forecasts of measurement errors in basic data T2 - 22nd Annual Western Snow Conference Y1 - 1954 A1 - Dean, W.W. A1 - Frost, W.T. A1 - Kuehl, D.W. KW - Statistical analysis, Water supply forecasting AB - A study was made of random sampling errors inherent to hydrologic data used for statistical development of multiple-linear regression formula to forecast the probable season water supply. Random errors were induced into basic data of both the dependent and independent variables and multiple linear equations were developed. The usual statistical parameters of correlation coefficient and standard error were compared with those formulas developed where the obvious random errors were NOT induced. These tests indicated that the introduction of errors in the magnitude chosen did not cause any large effects in the regression equation. It is suggested that every effort be made to gather and use data without errors in measurement and keep hydrologic data up to standard. JF - 22nd Annual Western Snow Conference T3 - Proceedings of the 22nd Annual Western Snow Conference PB - Western Snow Conference CY - Salt Lake City, Utah ER - TY - Generic T1 - A systematized regression forecasting method T2 - 21st Annual Western Snow Conference Y1 - 1953 A1 - Barton, M. KW - Statistical analysis, Water supply forecasting AB - A statistical method is presented for developing an up-to-date streamflow forecasting formulas. The primary purpose being to assist the streamflow forecasters to prepare their data in a logical procedure with close checks as the complicated process of multiple regression development proceeds. Such a procedure enables the operator to detect any shift in the relationships and make corrections. A series of 9 tables illustrate the procedure. JF - 21st Annual Western Snow Conference T3 - Proceedings of the 21st Annual Western Snow Conference PB - Western Snow Conference CY - Boise, Idaho ER - TY - Generic T1 - An approach to streamflow forecasting T2 - 21st Annual Western Snow Conference Y1 - 1953 A1 - Fulcher, M.K. KW - Statistical analysis, Water supply forecasting AB - A water supply forecast scheme is presented for the Colorado River above Grand Canyon. A statistical study of 9 tributary streams resulted in a decision to treat each tributary by itself and then route them by correlation procedures for a collective forecast at Grand Canyon. The Green River above Linwood is used as the pilot study. Data from 10 precipitation stations were weighed by the Thiessen method. These data were used as a soil priming factor from the preceding fall months. Snow survey data from 9 courses were used for April 1 forecasts. Fall and winter temperatures through March were used as a temperature factor. Multiple regression formula are solve with the 4 variables, resulting in a multiple correlation coefficient of 0.918. JF - 21st Annual Western Snow Conference T3 - Proceedings of the 21st Annual Western Snow Conference PB - Western Snow Conference CY - Boise, Idaho ER - TY - Generic T1 - Use of snow surveys in planning regulation of Columbia River floods T2 - 19th Annual Western Snow Conference Y1 - 1951 A1 - Work, R.A. A1 - Wilm, H.G. A1 - Nelson, M.W. KW - Statistical analysis, Water supply forecasting AB -

A practical method for making predictions of volumetric yield and flood discharges from snow is presented. Available data on the water stored in snow in the spring and during subsequent precipitation are obtained from 43 selected snow courses. The predictions are accompanied by estimates of error and probable limits within which the real yield or flood discharge is likely to fall, by statistical means. Two-thirds of the total error in predicting peak discharges is in the error associated with the relations of flood volume to snow water. Later season forecasts become progressively more precise. The effects of early season temperatures on peak discharge were indirectly evaluated by subtracting April volume from the estimated April-June volume, and relating flood discharges only to the remaining amount expected to flow during the last part of the 3-month period.Discussion by Clarence Pederson.

JF - 19th Annual Western Snow Conference T3 - Proceedings of the 19th Annual Western Snow Conference PB - Western Snow Conference CY - Victoria, British Columbia UR - sites/westernsnowconference.org/PDFs/1951WorkB.pdf ER - TY - Generic T1 - Establishing first year-normals on the basis of accumulated showfall snd some forecasts from runoff ratios T2 - 5th Annual Western Interstate Snow Survey Conference Y1 - 1937 A1 - Farrow, R.C. KW - Statistical analysis, Water supply forecasting AB - Three snow courses (one in each area) were laid out in 1937 at Glacier in the Selkirks, at Field in the Rockies, and at Fernie in the Southern Canadian Rockies. The location are near various precipitation stations whose data can be related to runoff at higher elevations. Sampling data from the 3 courses, the method used in obtaining a tentative first year normal, the mechanics of forecasting used, and the application of the forecast to points further downstream by use of runoff ratio factors are discussed. The percentage method is compared with the density method in establishing first-year snow course normals. It is concluded that a relationship between snowfall data and runoff is evident and that precipitation during runoff does not affect runoff. A refutation by Carl Elges of the density method is contained in the discussion. (See also SIP U1695 and WSC 35-37). JF - 5th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 5th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part II: CY - Davis, California ER - TY - Generic T1 - Winter precipitation versus snow survey for forecasting on Skagit River, Washington T2 - 5th Annual Western Interstate Snow Survey Conference Y1 - 1937 A1 - Leaver, R. KW - Statistical analysis, Water supply forecasting AB - A discussion of a paper on the monthly flow forecast of the Skagit River at Diablo Dam is presented. The monthly precipitation on 1100 sq. mi. of drainage area and the monthly mean inflow into the reservoir over a 25 year period were compared. It is shown that 68.7 percent of the rainfall enters the reservoir in an average year. Also half of the rainfall occurs from October thru December; the runoff is less than 18% during the same period. The difference forms a surplus to be drawn upon during the remaining 9 months. Each year the percentage of normal precipitation for Oct.-March is near to the percentage of normal inflow from April-Sept. The flow of the river for each particular period can be predicted within a mean average of 5% from the 25 year record by summing up the maximum and minimum figures for each month. The value derived by using the snow survey seems questionable since the prediction of increase runoff from snow-reservoir conditions is affected by temperature. Discussion by H.H. Boardman. JF - 5th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 5th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part II: CY - Davis, California ER - TY - Generic T1 - Calculation of normals for use with snow survey data T2 - 4th Annual Western Interstate Snow Survey Conference Y1 - 1936 A1 - Lee, C.H. KW - Statistical analysis, Water supply forecasting AB - Two principal methods are used to forecast summer run-off from snow survey data: the area method, which gives quantitative results but requires gathering field information and is seldom practical for use at present; and the percentage method, which expresses snow cover for any given time as a percent of the normal and requires stable normal values. A 25-year record is sufficient for stable values in humid regions and a 40- to 5--year record is sufficient for semi-arid and dry regions. It is now generally impractical to compute snow normals for snow-cover data alone. JF - 4th Annual Western Interstate Snow Survey Conference T3 - Proceedings of the 4th Annual Western Interstate Snow Survey Conference PB - American Geophysical Union, Transactions, Part II: CY - Pasadena, California ER -