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