Pond Boss Forums INTRO Questions & Observations Runoff and sand bag question

Two questions: We have sandy soils around our pond which we finally have common bermuda and winter grasses established around. Seems to do a good job of holding the soils but my question has to do with runoff - do you get more or less runoff from grass covered soils versus bare soil? It seems obvious that the grasses need moisture to grow and will use some of this rainfall for that purpose, but does the grass put somewhat of a seal to deter deeper saturation? It seems that I get less runoff into the pond from our rainfall now that the grass is established.

Second question has to do with the use of sandbags. I have a few areas that continue to erode taking any establishes grasses with it. My experience is that the banks seem to melt and level with a lot of rain. Has anyone used sandbags effectively to keep the banks from collapsing and eroding into their ponds at erosion points?

Cap,it seems to me that grass will slow down runoff because its restrictig water flow.But,on the other hand if you dont have it yous soil will just wash into the pond with the water and pretty soon your pondwill be ful of silt.
Grass washout,it would be my guess you have to much sand in your soil and the roots dont have anything to hold on to.
Now,all that being said you better wait for someone who knows whot thier talking about cause I aint it.
where in e texas cause If your close I got a bunch of clayish dirt you can have for nothing,all you have to do is come get it...Ill even load it for ya

We are in Mineola North of Tyler. We have decent clay on 3 sides of the pond and on the bottom, but my contractor was hesitant to put much clay on the upstream side of the pond for fear of sealing off the springs. Even in areas where he put clay over the bank, the deep sands on the uphill side percolate water and collapse creating a ravine, especially where these springs originate. I was hoping sand bags could hold the bank in place, but still let runoff and the stprings percolate through them. I do appreciate your offer.

Could you use rock or riprap maybe?

I used rock which failed, do to the same reason your grass did, so I cemented in the rock and carried it to a level that was below, low waterline, but that is failing, same reason.
My guess would be a plant that has a deep root system. I have a grass here, it may also be available to you, that has a 12' root system, is non invasive. It needs cutting to about 8" when it reaches about 40". I have used it in various places around the pond successfully. It is called vetiver. I don't think the process can be completely stopped but it can be slowed. I read about a rip rap solution that suggested laying down 10" or gravel and cover with that much or more rock. Which maybe where I am going to go eventually, the recommended slope was 4 to 1.

Re your first question about the grass, what happens to me is that the rain soaks in better in the planted areas and part of the water that seeps into the pond, so instead of getting the runoff in a rush I get in a more measured amount over time.

captain 1
You can call my office and we can talk about this, or email me. Office is 1.800.882.3478(DIRT)or email at mikeotto@ottosdirtservice.com. Sheri is there from 8 to noon and she can assist you or will return your call the next day.
Otto

Grass has a lower coefficient of runoff than bare soil. It will hold the water longer, and more will soak into the ground. You will get more runoff from bare soil, but that water which runs off will also be carrying more sediment, into your pond. I'm a civil engineer, but don't let that fool you. I just had a man spend 2 days on a bull dozer building diversion terraces on my property to direct water that I had assumed would flow into the pond. Costly mistake. Only after the pond didn't fill did I decide to perform a topographic survey of my entire pasture and found out that there was an optical illusion, and most of the water drained not where I thought it did.

Of course, now with the terraces directing water into the pond with nowhere else to go, it should fill right up....hold your breath.

We added a couple terraces early on after heavy rains dug a 5 foot deep trench down the hillside depositing a lot of sand to the bottom. Unfortunately, that also diverted runoff elsewhere. I likely have an inadequate watershed to keep my pond full - especially with the low rainfall in recent months. I am about to re-direct some of the terraces into a main channel - but at an angle that should minimize erosion. The established grasses should help as well. My main battle is keeping the depth of the water acceptable at the banks. Sand wants to level to flat!