Examination of Specified and Maximum Release Rules in HEC-ResSim

This post will demonstrate the behavior of HEC-ResSim with a combination of Specified and Maximum release rules.

To develop this post, a simple model with one reservoir was created.  This is shown below.

The simulation begins at the top of conservation pool with a constant 1,000 cfs of inflow entering the reservoir.

In the first simulation, a specified release rule of 500 cfs is placed in the rule set at a higher priority than a maximum release rule of 400 cfs. 

Recall that ResSim want to release as much as possible since the pool rises into the flood pool.  ResSim uses the specified release even though its value exceeds the maximum release since the specified release is a higher priority rule.  This is shown in the figure below (green line in bottom plot shows the release; release is set to 500 cfs until pool reaches top of flood pool).

In the next simulation, these priority of these two rules are reversed.  This is shown in the figure below.

Since the maximum release is now the higher priority, the release is limited to 400 cfs until the top of the flood pool is reached.  This is shown in the figure below.