SWC Methodology - TWG

February 19, 2015

Settlement Document Subject to I.R.E. 408

Update on Natural Flow Predictor Models

April 1 Models• Considering using other forecasts• Predictor models for all SWC members • Relationship between Box Canyon and

Blackfoot to Milner reach gains.

NRCS USACOE/USBR Averaged NRCS/USACOE&USBR

2000 25% 12% 18%

2001 1% 13% 7%

2002 14% 12% 13%

2003 7% 3% 5%

2004 -19% -13% -16%

2005 10% 10% 10%

2006 25% 24% 24%

2007 1% 0% 1%

2008 -10% -12% -11%

2009 -36% -26% -31%

2010 -13% -20% -17%

2011 -2% 12% 5%

2012 5% 16% 11%

2013 23% 14% 19%

2014 2% 3% 3%

Average 2% 3% 3%

Standard Deviation 18% 15% 16%

New TFCC April Natural Flow Predictor

TFCC= 62.01 (Heise) +12,980(Box) – 609,600

Where:TFCC = TFCC natural flow supply from April to October;Hei = Heise natural flow forecast from April – July in (KAF);Box = Box Canyon total flow from November through March (KAF).

Adjusted R2 p SE DOF F-statistic0.8664 <0.001 38,010 21 75.6

Current April Natural Flow ModelsSWC

MemberEquation

(less one standard error)R2

A&B y = 0.0092x - 19.747 0.887

AFRD2 y = 0.0742x - 141.14 0.8317

BID y = 0.0344x - 2.5853 0.7964

Milner y = 0.0102x - 19.412 0.9243

MID y = 0.0484x + 2.7178 0.7896

NSCC y = 0.1562x - 53.005 0.8952

TFCC y = 0.0658x + 626.37 0.5416

Where:y = Natural flow April – October for the SWC Member (AF);x = Heise Natural Flow (April 1 – July 31). USBR/ACOE Heise forecast is used in April.

*To error on the side of the SWC , natural flow predictions are one standard error below regression line.

April 1 Predictor Models for other SWC Members

• Used the same variables that were used for TFCC model:– Heise– Box Canyon

• Found no model improvement for:– A&B– AFRD2 ?– Milner– All have late priority NF rights

SWC Member

Water Right Priorities

A&B 1939

AFRD2 1921

BID 1903, 1908, 1939

Milner 1916, 1939, 1939

MID 1903, 1908, 1939

NSCC 1900, 1905, 1908, 1915, 1920

TFCC 1900, 1915, 1939

Multilinear Regression Model : AFRD24to10 = HeiseAprtoJulKAF + Box11to3)Residuals: Min 1Q Median 3Q Max -64494 -22886 -6416 19101 64373

Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) -435713.23 170094.89 -2.562 0.0182 * HeiseAprtoJulKAF 73.22 6.70 10.928 4.01e-10 ***Box11to3 3317.91 1673.59 1.983 0.0607 . ---Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 37290 on 21 degrees of freedomMultiple R-squared: 0.8583, Adjusted R-squared: 0.8448 F-statistic: 63.58 on 2 and 21 DF, p-value: 1.233e-09

AFRD2 April 1 Models

Linear Regression Model: AFRD24to10 = HeiseAprtoJulKAF

Residuals: Min 1Q Median 3Q Max -69999 -23845 -1323 20850 79034

Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) -1.014e+05 2.389e+04 -4.247 0.00033 ***HeiseAprtoJulKAF 7.418e+01 7.114e+00 10.428 5.6e-10 ***---Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 39700 on 22 degrees of freedomMultiple R-squared: 0.8317, Adjusted R-squared: 0.8241 F-statistic: 108.7 on 1 and 22 DF, p-value: 5.604e-10

April 1 MLR Predictor ModelsSWC

MemberPredictor Model

Natural Flow Diversions (April – October)Adjusted

R2SE F-Statistic

BID BID = 33.64(Heise) + 2570(Box) – 240,800 0.8546 17,100 68.61

MID MID = 47.12(Heise) + 4302(Box) – 401,000 0.8786 22,070 84.22

NSCC NSCC = 154.19(Heise) + 6834.23(Box) – 677,949 0.9151 55,950 125

TFCC TFCC= 62.01 (Heise) +12,980(Box) – 609,600 0.8664 38,010 75.6

Where:Heise is the total Heise natural flow from April – June in (KAF); Box = Box Canyon total flow from November through March (KAF).

Current April Natural Flow ModelsSWC

MemberEquation

(less one standard error)R2

A&B y = 0.0092x - 19.747 0.887

AFRD2 y = 0.0742x - 141.14 0.8317

BID y = 0.0344x - 2.5853 0.7964

Milner y = 0.0102x - 19.412 0.9243

MID y = 0.0484x + 2.7178 0.7896

NSCC y = 0.1562x - 53.005 0.8952

TFCC y = 0.0658x + 626.37 0.5416

Where:y = Natural flow April – October for the SWC Member (AF);x = Heise Natural Flow (April 1 – July 31). USBR/ACOE Heise forecast is used in April.

*To error on the side of the SWC , natural flow predictions are one standard error below regression line.

Box Canyon Discussion

July 1 Models• Two Oceans Plateau SWE – Consider using an earlier date to remove years with

zeros• Concerns over using Spring Creek data.– Consider using only metered data– Investigate using other indicators

• Tyhee (missing data 1995 – 2001)• Wells

• Predict total natural flow in the Blackfoot to Milner reach then allocate by priority

Two Oceans Plateau

• Looked at June 1 and June 15.• June 15 had better results than June 1. • June 15 data set has 4 years with zero SWE• July 1 data set has 13 years with zero SWE

July 1 MLR Predictor ModelsSWC

MemberAdjusted

R2SE F-Statistic

BID Old 0.8672New 0.828

12,81014,580

51.0637.9

MID Old 0.8808New 0.8438

17,49020,020

57.6342.42

NSCC 0.9003New 0.8593

39,82047,300

70.2247.83

TFCC 0.8304New 0.8511

31,24029,270

38.5444.83

Where:Heise is the total Heise natural flow from April – June in (KAF);SpringCreek is Spring Creek total flow from January - May (KAF);TwoOceans is the July 15 Snow Water Equivalent (in).

Spring Creek Alternatives