Runoff curve number

Okay, so you know when it rains outside and the water flows over the ground? Well, sometimes this can cause flooding and it's important for us to know how much water is going to flow so we can plan and prepare for it.

That's where a runoff curve number comes in. It's like a little number that helps us figure out how much rainwater is going to run off the ground and into rivers and streams.

Let's say we have a big open field and it starts raining. Some of the water will soak into the ground, some will evaporate into the air and some will run off. The runoff curve number helps us figure out how much of the rainwater will run off and how much will soak in or evaporate.

We look at different factors like how much grass or pavement is on the ground, how steep the ground is, and how much rain is falling. Then we use these factors to come up with our little number, the runoff curve number.

The higher the number, the more rainwater will run off the ground. If we have a low number, that means more of the water will soak into the ground and we won't have as much runoff.

So, basically, the runoff curve number helps us predict how much water will flow over the ground when it rains, which is important for planning and preventing flooding.