ResSim 3.5 New or Updated Content

UPDATED IN RESSIM 3.5 As of ResSim 3.5, Release Allocation is now defined by sets, like operations. BUG IN RESSIM 3.5There are some bugs that were introduced when making this update - they relate to interaction with the UI.

As we'll see in the next chapter when we create rules, rules can be specified to apply to a specific outlet, thus imposing an "allocation" of the release determined for that rule to the identified outlet. Although rule-based allocation takes precedence, there are usually releases that are not specifically allocated by the rules; these are typically the releases made due to rules or operations that are applied to the dam or reservoir as a whole and are the ones the Release Allocation feature is intended to manage.

In ResSim, a Global Variable is a data object that modelers can use to represent data needed or produced by their model and its scripts. Input Global Variables are assigned values through the Alternative Editor when defining an alternative.  Output Global Variables are defined during through a script during the compute. The intention of global variables is to allow an operation to be specified in the abstract (say through rules and state variables) and defined with different parameters for each alternative.

Each alternative represents the combination of a reservoir network, a selection of one operation set per reservoir, the specification of the initial conditions of each reservoir, and the selection of inflows and other input time-series datasets needed by your model. An Alternative consists of a Reservoir Network (previously created from a Configuration), Run Control specifications, an Operation Set for each Reservoir in the network, a Storage Balance Operation Set for each Reservoir System in the network (if applicable), a definition of initial (Lookback) conditions, and a mapping of all Time-Series records to identified local inflows. To develop an Alternative, you use the Alternative Editor to name the Alternative and give it a description, define the Time Step and Flow Computation method, select Reservoir Operation Sets, select System Operation Sets (if applicable), select a Lookback Type, associate time-series data with locations, associate observed data with locations, and save the Alternative you have created. This chapter will guide you through these steps.

A Flow Rate of Change Limit rule specifies the allowable change when increasing or decreasing release values (a.k.a., "ramping rates"). A single rule of this type will only limit a rising release or a falling release, but not both. To describe both increasing and decreasing limits, you must define two rules and set the type of one to increasing and the other to decreasing. A rule of this type can be assigned to any release element to influence the behavior of that element.

To access the Options Editor:

• Select Options… from the Tools menu of any ResSim module.

As shown in "Figure: ResSim Options Editor", the Options Editor is arranged in tabs. Some tabs are module dependent, such as the Simulation tab which only appears when the Options Editor is accessed from the Simulation module of ResSim.

Starting ResSim

To begin modeling reservoirs, you must first start ResSim. Like most other Windows applications, you can launch ResSim by:

• Double-clicking the HEC-ResSim icon on your Windows desktop ("Figure: ResSim Desktop Icon"), or
  

UPDATED IN RESSIM 3.5

A Prescribed Release rule is a rule that can be used to "hand regulate" a reservoir. That means that you can tell the reservoir how to operate over a specific time window with a specific operating objective. The operating objective is defined by selecting an Operator and an accompanying value. For example, if the Operator is "Rel % Inflow", the Value is the percentage of inflow that should be released.

UPDATED IN RESSIM 3.5

The Menu Bar in the OSI is important to the setup and configuration of the OSI. After configuring the OSI, menus will be used less frequently.

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