What is the best way to model surge relief valve (SRV) in WaterGEMS or WaterCAD?
Surge Relief Valves are more typically used in HAMMER as a surge or transient protection device. The Surge Valve element acts as a junction in the initial conditions regardless of the initial pressure. There may be modeling cases where a user may want to model the effects of a valve that acts like a surge valve. In such cases, you can try the following steps.
To model a surge relief valve with WaterGEMS or WaterCAD, you would create a branch link (pipe at a tee) to a Pressure Sustaining Valve (PSV). Then you would put a reservoir node at the ground elevations just downstream of the PSV. The setting on the PSV should be the pressure or HGL you want to maintain upstream. This could be used to model an open surge relief valve.
This will provide results for steady conditions. Note that for transient results, a surge valve element would need to be used. See the link below for information on modeling SRVs in HAMMER.
Modeling Reference - Surge Valves
http://communities.bentley.com/products/hydraulics___hydrology/f/5925/t/94038.aspx (Forum post)