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Integrated Water Resource Planning Systems User Forum. WRYM - New features 1 July 2004. Layout – new features. Automated search for stochastic firm yield Alternative method of modeling IFR - LHWP Reconciliation scenario analysis using the historical sequence – F16.DAT.
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Integrated Water Resource Planning Systems User Forum WRYM - New features 1 July 2004
Layout – new features • Automated search for stochastic firm yield • Alternative method of modeling IFR - LHWP • Reconciliation scenario analysis using the historical sequence – F16.DAT
Automatic search for stochastic firm yield (1 of 2) • User defines the assurance level at which the yield needs to be determined (1:50, 1:20 return period) • Iterative analyses are undertaken to search for the firm yield using an upper and lower target drafts as starting point • User provides the initial upper and lower limits
Automatic search for stochastic firm yield (2 of 2) • Activation variable: OPTFY=2, FO1.DAT • Upper and lower target drafts defined through variable YIELD • New variable TARGRI defines the recurrence interval for which the yield is determined (“50” for 1:50 or “20” for 1:20), F01.DAT
Alternative method of simulating the IFR (1 of 4) • Application: Lesotho Highlands Water Project • Method approved by the Lesotho Highlands Development Authority • Use annual total flows as driver for IFRs – as apposed to normal method using monthly flow • Additional data provided in the F14.DAT file
Alternative method of simulating the IFR (2 of 4) • Two options are available: • 1 – Annual IFR is a constant percentage of the annual natural inflows as defined by a set of reference inflow nodes – smooth annual IFR duration curve • 2 - User defines finite set of IFR definitions and one definition is imposed exactly for a range of annual inflows as defined by a set of reference inflow nodes – IFR for a year is one out of the set of IFR values
Alternative method of simulating the IFR (3 of 4) • Monthly disagregation: • Apply one of a set of user defined monthly values (12) for a simulation year which are selected based on a range of annual natural inflows that are referenced by a set of inflow nodes • Option 1 > Normalization of 12 monthly values are used • Option 2 > Exact specified 12 monthly values are used
Alternative method of simulating the IFR (4 of 4) • Example of additional data in F14.DAT file: . . 2 / Number of annual IFR structures 276 1 5 0.121 /IFR channel, # of inflow nodes, # of classes, IFR factor 21 / Reference node number 756.6 3.21 22.74 12.21 11.48 12.14 11.48 7.74 4.71 7.35 4.45 7.18 4.09 563.8 2.95 13.61 3.21 11.48 12.14 6.98 7.74 3.21 2.85 2.41 6.91 3.83 501.7 2.95 12.11 3.21 7.98 12.14 3.48 7.74 3.21 2.85 2.41 6.67 2.15 348.4 2.68 2.85 3.08 7.71 12.14 2.95 4.09 2.41 1.45 1.61 6.64 2.33 0.0 2.28 2.33 2.68 2.68 2.30 2.41 6.70 2.14 1.81 1.61 5.97 2.07 Monthly IFR flows (m3/s) Annual reference flows
Reconciliation Scenario Analysis • A method to reconcile the water requirements with the available water by taking the interdependencies among users in a water resource system into account • Apply a water user type risk criteria that portions the demand into assurance categories – annual sequence only • Scenario defined by single multiplication factor for each abstraction channel in a system – input variables allow multiple scenario runs, maximum 10 • Factors applied to min-max and specified demand abstraction channel types • Simulation results assessed for compliance with risk criteria and summary of all channels presented as output
Reconciliation Scenario Analysis Model input (F16.DAT): 2 5 1 / # user types, # risk criteria levels, # scenarios 50 20 10 5 2 / Recurrence interval for each criteria level (1:X years) 0.0 0.5 0.2 0.1 0.2 / Portion of demand for each criteria level – Type 1 1.0 0.0 0.0 0.0 0.0 / Portion of demand for each criteria level – Type 2 5 / Number of water use channels 27 1 1.00 /Channel number, user type, portion of demand to be imposed 29 1 0.01 /Channel number, user type, portion of demand to be imposed 32 1 0.03 /Channel number, user type, portion of demand to be imposed 33 2 0.81 /Channel number, user type, portion of demand to be imposed 901 2 0.15 /Channel number, user type, portion of demand to be imposed Add further columns of factors for more scenarios, maximum = 10
Reconciliation Scenario Analysis Model results (DBG.OUT): Reconciliation summary | Chn. nr | Type |User T| Demand(1) | Demand(2) | Supply | Fct | Recon(F/T) |Failure Years per Criteria Level 27 2 1 3.513 3.513 3.513 1.000 T 0 0 0 0 0 29 2 1 9.499 0.095 0.089 0.010 T 0 0 0 14 18 32 2 1 29.260 0.878 0.859 0.030 T 0 0 0 0 17 33 1 2 1.578 1.278 1.278 0.810 T 1 1 1 1 1 901 1 2 1.578 0.237 0.237 0.150 T 1 1 1 1 1