Merge Stage-Discharge

This command combines two or more stage-discharge files into a single, merged file.  Ponds with two or more spillways (for example, a principal and emergency spillway) will outflow increasing volumes of water at higher elevations (stages) in the pond.  In many ponds, a principal spillway allows baseline, non-storm flow to exit the pond, and an emergency spillway, placed at a higher elevation, permits storm flows to exit the pond as the water in the pond rises.  Because flows increase for virtually all spillway types with increasing water elevation above the spillway, stage-discharge files (.STG files) will show increasing flow at increasing elevation.  For ponds with more than one spillway, it is necessary to combine or merge the flows from the multiple spillways as they are encountered at higher elevation.  The most typical application is to merge the flow from the principal and emergency spillways that are used on most pond designs.  (See graphic in Draw Stage-Storage Curve.)   These merged stage-discharge files are then used in the command Locate Structures, found under the Watershed pulldown menu.  This command will also merge multiple selections of single stage-discharge files, or will accept a "pre-merged" stage-discharge file.  In combination with the pond stage-storage files, the structures in a watershed layout will be used to compute hydrographs and determine the impact of pond placement and spillway design on reducing storm flows.

Prompts

The command is dialog-driven, in this order:

First Stage-Discharge File to Merge. (It is recommended to load the lowest elevation spillway file, typically the principal spillway stage-discharge file.)
Next Stage-Discharge File to Merge. (Here you would typically load the emergency spillway stage-discharge file.)
Merge Another Stage-Discharge File? Yes/No. Click Yes if there is another stage-discharge file, otherwise click No.
Choose the Output Stage-Discharge File. Name the output stage-discharge file.

Pulldown Menu Location: Structure in Hydrology
Keyboard Command: merge_stg
Prerequisite: Spillway design routines that create Stage-Discharge Files, such as Drop Pipe Spillway Design, Pond Weir Spillway Design, Open Channel (Manning's Eq) and Pipe Culvert Design.