How to Approximate a Timer in the RTC Rules of SWMM 5
2. Closing the weir by staggered Storage node depth,
3. Opening the weir gradually when the inflow increases
4. Closing the weir by a combination of Node Depth IF statements and Control Curve rules
For example, you can have the Weir Setting controlled the Node Depth, Link Inflow and Node Inflow simultaneously approximately with the depth and the inflow parameters closing the weir by proxy instead of by time since the closing.