We use the USGS website to monitor current river flow levels in our area. Here's what you can expect based on the current river flow:

•  GREEN | Up to 300 ft³/s : The current is very slow. Paddling on the river will be similar to paddling on a lake except for a few sections (~50ft) with a little bit of current. Conditions are good. The river is typically at this level.
  
•  BLUE | 301-600 ft³/s : The current is slow. You will need to work a bit when traveling up stream against the current. Conditions are still good for almost all riders. The river is typically at this level for a few days after a moderate rainfall.
•  RED | 601 ft³/s or more : We typically cancel rides when the river is at this level. The river current is strong and potentially dangerous. Paddling up stream is difficult or impossible. The river can be at this level for 3-10 days after a heavy rainfall.
  

When rain falls to the north of the Dublin Bridge Park District (Jerome, Ostrander, Powell, Delaware, etc.) the water eventually flows into the Scioto River at our location. Rainfall in that watershed area has a direct impact on the river levels where we provide rides. A good way to predict whether the river flow will be too high for kayaking is to click on this rainfall map and change the date range to the last 7 days. If there has been more than an inch of rainfall in the area north of Dublin (Marysville, Delaware, Marion, etc.) in the last 7 days, there is a good chance the river will be too high for kayaking.

As you can see on the USGS website, when the river flow goes up high, it typically takes several days for it to fall back below safe levels. When the river starts going down, we typically find that it decreases about 1000-1500cfs per day (assuming there is no rain). For example, if there is 2 inches of rainfall in the watershed area and the river increases to 6000cfs, it will probably take 5-10 days without any rain before the river lowers back to safe levels. Also keep in mind... When there is an increase in the river level due to rain, there is often an initial sharp surge in the river level that lasts for about a day and then the river starts dropping, but then a secondary surge starts about 1.5 days after the initial surge. That is likely due to water flow from the area north of Dublin finally making it to our location from many miles away.

Those are some of the reasons why it is difficult for us to predict when the river will be safe in our area for kayaking. :( And, that's why we constantly monitor the river levels. :) If we believe that the conditions are not good for fun and safe rides, we cancel our rides.