Level Sill Spillways vs. Normal Spillways

Kaven here wants to know, on the total water design at Zaytuna Farm, the legend suggests at 0.53 that there are two types of spillways. What counts as a level sill spillway and what counts as a normal spillway? Why is this difference in labeling? When is one applicable over the other? Well the level sill spillways we usually put on swales or at least extension walls off the end of dams so that we can get the spillway away from the dam and when we're on ground that might be less stable. Here is a big spillway and it's a standard spillway. Cameraman stood on the dam wall the hill the side of the hill is behind me on the valley and this big channel here is the spillway and we're right at the bottom of the property and we can't run a swale off from here because we're right at the bottom there's no level here it goes down to the creek and that's all forested anyway. So there's no swale attachment on this one we're on pretty solid ground here it's not the type of ground that erodes. So we've got a normal spillway and a big one that runs off on the side of the valley and drops into the valley over there. There's an emergency spillway on the other side that's exactly the same it's just a little bit higher so if we get a big flow that one goes and this one goes at the same time. Now if we had a swale and we were connected on higher country and it was a bit steeper or it was less stable or the soil was potentially more erodible we can put a level sill spillway on the swale and really take the pressure off the overflow in the more sensitive situation. So that's where we we put our level sills also they can go anywhere along the swale so we can choose where we displace the water when we're down the bottom here on a big dam like this we're on solid ground we're near the creek we can't run a swale off so we just put a big stable spillway straight out from here and we make sure we can take a lot of volume because there's going to be a lot of volume down the bottom here.