Erosion Control Structure: One Rock Dam

[Music] my name is aaron kaufman i'm the founder of southwest urban hydrology and today we're going to be talking about three structures that are found in a technical field guide produced by the kevira coalition and watershed artisans the three structures include one rock dam a rock rundown and a medea luna the intention of all these structures is to conserve soil in kind of low energy systems typically on uplands we hope you find it's beneficial in restoring sections of your property or land a one rock dam is an erosion control structure built in the bed of a straight low-grade channel using a single layer of rock so at this particular site we're going to be building a one rock dam the intention here is to slow the velocity of water as it's moving through a straight section of channel step one dig a trench and build the splash pad first thing we can do is we can actually excavate a little bit of this soil it only needs to be about one or two rocks wide at this point we'll start to grab ideally some flatter stones uh that can be set kind of against that or kind of similar to that original elevation always trying to create or put the flattest part of the stone in contact with the ground so it doesn't tip or roll because we're going to leave the second row just slightly elevated it's still embedded but it's slightly elevated so that the next section of stones that we built here are going to be pushing against the back of the top of this stone nothing's going to try and tip over the next one as we're building this entire structure we want to make sure that it remains somewhat concave so that the majority of the water remains or kind of centered through the structure if it was completely flat across here the concern would be that water could potentially get around it step two seed the area above the splash pad we've just collected some native seed off the landscape this is an alkali sacotone you can use wildflowers or other forbs and as we put stones above it the stones will serve as a mulch so there's no need to actually bury any of this the seeds should germinate from underneath the stone step 3 build upstream from the splash pad at this point we're going to start to use stones that continue to maintain that concave shape but also start to lift the elevation of the of the actual structure this is a one rock dam meaning that it's only one rock high we're not going to stack any stones on top of each other but we will get lift or a little bit of height from the stones that we lay down you don't want to put any excess height in the middle of this because it'll force water around it too much so try and maintain kind of a constant uh elevation across that middle if you recall we excavated a small um kind of a footer area we took that sediment or that soil we tossed it up channel up here so it'll wash into the structure uh during the next storm uh we embedded a couple of rows of stone that are kind of at the same elevation of the original channel bed we then built the splash pad so that it's even or the height of the original channel bed and then cast a little bit of grass seed and some wildflower mix in the channel above this area and then proceeded to construct the rest of the one rock dam using stones that are kind of one rock high not stacked fitting them together as tightly as possible and ultimately we've maintained this kind of concave shape so that water should pass through the center of it as the water's passing through it'll hit these stones we'll have to meander between each one uh it'll slow down drop the sediment and a little bit of extra moisture the rocks will maintain a mulch to improve soil moisture below them so that hopefully we get some germination of those seeds but the one final kind of step here is we're going to take a little bit of gravel and if you see any small gaps between the stones you can actually start to armor it um even a little bit more by just kind of finding places to put those in there just so it fills in uh some of the holes or the places where the the cobble didn't fit together perfectly you

Channel: Quivira Coalition

Views: 15,809

Keywords: erosion control, one rock dam, quivira coalition

Id: qvrp6qRvYbo

Length: 4min 35sec (275 seconds)

Published: Wed Jan 19 2022