PCWA MFP Operations Model All Models are Wrong But Some Models are Useful

What is a Model? A Simulation Model is a mathematical representation of a physical system that includes: Rivers Reservoirs Conveyance and Release Facilities Tunnels, Penstocks & Powerhouses, Streamflow release valves Operating Rules, Licenses and Agreements

What is a Model? The Model routes water (Input Hydrology) through the System (mathematical representation of the physical world) according to Rules

What is a Model? A model chooses how water is routed through the system in order to meet certain criteria and goals. A model allows us to measure the impact that changes to the input set will have on the output set.

What are the Rules? Rules are inputs to the Model Rules represent decisions made by the operators Rules fix operating parameters that can vary from run to run

Examples of Rules Instream flow requirements Storage level requirements and targets Use of discretionary water supplies Meet Consumptive Demands Generate Power Provide Recreation

Other Model Inputs Flow (Hydrology) - PCWA believes that it has a reasonably accurate record of Project flows since the project began operation in 1968 For each different set of inputs, we intend to generate output using the same identical set of historic hydrology

Other Model Inputs Fixed Criteria - project parameters that cannot be changed without physical alteration of the Project. Fixed Criteria include: Tunnels and Turbine capacities Outlet capacities Elevations

Other Model Inputs Water Supply Demands - special class of Rules Consumptive demands at Folsom Reservoir Consumptive demands at Auburn Pump Station Environmental Demands (Water Forum Agreement)

Model Outputs Tables to verify that the Rules are met Rules guide the operation of the model, but may not be met 100% of the time. For example, minimum instream releases will not be met if a reservoir runs dry. Having the flexibility to violate rules helps provide information.

Model Outputs Reservoir Level Trace Identify excursions from “preferred” operation - too high (spills and loss of generation) or too low (risk of failure to meet consumptive demand) Power Generation

Benchmark and Baseline A Benchmark Run is used to verify that the model reasonably represents actual historic operations The Baseline Run is the run against which all Alternative Model Runs are compared to determine the impacts of proposed conditions on the MFP operation

Benchmark and Baseline PCWA proposes that the difference between the Benchmark and the Baseline Runs is that the Benchmark Run uses historic consumptive water demands and the Baseline Run uses buildout consumptive water demands

Using the Model Model Consumptive Demands Hydrology Operating Rules Fixed Criteria Verification Tables Reservoir Levels Input Output Baseline Study Generation Model Consumptive Demands Hydrology Operating Rules (Changes) Fixed Criteria Verification Tables Reservoir Levels Input Output Generation Alternative Study Assess Impacts Compare Outside Model Inside Model

Assessing Impacts The Model Does Not assess environmental impacts The model only provides comparative information on water supply and power generation for Alt Model Runs Assessment of the full impacts of any Model Run is done by people

Assessing Impacts An analysis of the benefits and costs of each alternative may be viewed differently by each person To develop alternatives based upon environmental parameters requires completion of the 1st year of field studies. March 2009.

Alternative Model Runs The desire to create a given environmental condition leads stakeholders to suggest changes to the rules The resulting model run shows the impact of the rule change on water supply and power generation

Where are we now? The Model is operational Benchmark input set has been assembled for testing A draft users manual has been prepared

What do we do until 2009? Verification Education Development (betterments, hourly) Investigate physical limitations Find our sideboards: Dry year issues, Ralston Afterbay flexibility

How do we get there? Process: We need good process around our group understanding of how Modeling Alternatives are developed, run and assessed