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Estimation of Truckee Canal Losses. Truckee Canal Mass Balance. TRD = Truckee River Diversion (Gage nr Wadsworth) – Canal Inflow TDD = Truckee Division Diversion TCL = Truckee Canal Losses (Seepage + Evaporation) TCH = Truckee Canal Hazen (Gage nr Hazen)
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Estimation of Truckee Canal Losses
Truckee Canal Mass Balance TRD = Truckee River Diversion (Gage nr Wadsworth) – Canal Inflow TDD = Truckee Division Diversion TCL = Truckee Canal Losses (Seepage + Evaporation) TCH = Truckee Canal Hazen (Gage nr Hazen) Canal Outflow to Lahontan Reservoir Flow to Pyramid TDD Gage nr Hazen TCL TRD Truckee River TCH Gage nr Wads Inflow Vol. = Outflow Vol. TRD = TDD + TCL + TCH
Modeling Canal Losses • For RW Model – Ideally would like to relate losses canal flow • Normal depth flow – as flow ^, depth ^, wetted perim ^, seepage^ • Early attempts failed to establish good correlation due to many • reasons: • Normal depth conditions do not exist for much of the year with check structures. • Several lateral diversions along 18 mi. length. • Compounding gage errors.
Estimation of Truckee Canal Losses in the Current RiverWare TROF Model • Study by Coors and Mann: Modeled combination of • TDD + TCL (total depletion). • For the Ops model at time – no reason to separate. • TDD + TCL (Depletions) = TRD (Wads) – TCH (Hazen). • Analyzed 34 years of data (1970 – 2003).
Canal Flow and Depletion Characterization • TDD + TCL does not vary much from year to year. • Temporal seasonal pattern is very regular. • Irrigated acreage decreasing over time.
Verification of Modeled Depletions • The model averages the last 3 years of daily gage data to forecast TDD + TCL for the remainder of the year. • Accounts for decreasing irrigation acreage.
Comparison of Actual vs. Simulated TDD+TCL • Avg Annual Deviation = 7.1 KAF (16.8%)
Current Analysis to Improve Truckee Canal Loss Estimation • (Preliminary – for discussion) • Objective: Separate TDD and TCL to allow for • flexibility in changing TDD over time. • - Use of additional data to improve TCL/Flow • relationship (through 2010). • - Try monthly regression to account for variability • in checking, evaporation, and seepage rates.
Previous Work in 1996 for OCAP • Analysis of Truckee Canal Losses from 1967-1995 • TCL vs. Truckee Division Diversion + Truckee Canal Flow at Hazen • Three seasonal groups: • Summer (May-Sept) • Spring and Fall (March, April, Oct, Nov) • Winter (Dec-Feb) • Results
Previous Work in 1996 – Fig. 1 R2 =0.12 (Summer)
Previous Work in 1996 – Fig. 2 R2 =0.07 (Spring & Fall)
Previous Work in 1996 – Fig. 3 R2 =0.01 (Winter)
Hypothesis: • Truckee Canal Losses Increase with Increased Wetted Perimeter and Depth • Used a monthly break down to improve correlation between flow and loss • Tried to correlate canal loss with Wadsworth • gage flow • Two sets of data: 1967-1995 and 2001-2010
Hypothesis: Truckee Canal Losses Increase with Increased Wetted Perimeter and Depth
Monthly Results • Did not use TC losses that were 0’s, negative numbers, or outliers • We tried a power function fit, linear produced a better R-value • Significant improvement over previous seasonal regression
Data Issues / Sources of Error • Checking uncertainty • Compounding gage errors with lateral data • Long canal with diversions distributed along • the length of the canal • 12 hour travel time between TC Wadsworth gage and TC Hazen gage • Varying operational strategies
Moving Forward - Ideas for future improvements: • Try regressing to Hazen gage (TCID operates the TC differently with water running to Lahontan. If there is no water running to Lahontan then the TC is full checked up) • Try breaking data out by different operating periods: • Past-Feb 1999 • March 1999-Jan 5, 2008 (Dave Overvold Era) • Feb 2008-Present (After breach) • Fortran canal loss equation • Physical model? • Additional regressors? • Suggestions from group?