There are limits to how much you can do this. For river health, you need to maintain roughly even outflows. Too much release results in flooding, and too litt

There are limits to how much you can do this. For river health, you need to maintain roughly even outflows. Too much release results in flooding, and too little will dry up the river. But even outside of those extremes, you can have issues where high outflows inundate levies, followed by reduced outflows that lower the river, causing the soaked levies to collapse into the river. There are also fishery-health issues to consider. How much of an issue this is depends on what the situation is downstream; some damns have afterbays that can moderate these changes quite well, while others do not and are less able to rapidly change outflows like this. Basically, you might need to do some significant upgrades before you can use your hydro 'on demand' like this.