land erosion and stairs

[Lake Guy]

Hi,
I live on the northern side of rattlesnake. The land (about 150 ft) between my house and the water edge is a relatively steep slope - mostly soil and very few rocks. Unfortunately, the land has not been well maintained by a previous owner (we bought the place last Fall) and the soil around some of the concrete pilings that support the stairs leading up to the house is eroding (the concrete is fully visible in several pilings). The growth/vegetation is bad in these areas. I'm wondering if folks can recommend what I can do to remedy this? Do I need to bring in more soil to pack around these areas ? What can I plant that will make a strong root system around the stairs to minimize erosion? etc.... any advice would be great.
Thanks,
Lake Guy

[RTTOOL]

Originally Posted by lake guy

hi,
i live on the northern side of rattlesnake. The land (about 150 ft) between my house and the water edge is a relatively steep slope - mostly soil and very few rocks. Unfortunately, the land has not been well maintained by a previous owner (we bought the place last fall) and the soil around some of the concrete pilings that support the stairs leading up to the house is eroding (the concrete is fully visible in several pilings). The growth/vegetation is bad in these areas. I'm wondering if folks can recommend what i can do to remedy this? Do i need to bring in more soil to pack around these areas ? What can i plant that will make a strong root system around the stairs to minimize erosion? Etc.... Any advice would be great.
Thanks,
lake guy

need pictures to lead you in the right way..

[ApS]

It may be too late for the planting of trees. Added soil will eventually wash away. You'll likely need something engineered for soil retention, as was done across from Rattlesnake Island.

Directly across from your Rattlesnake location is a modern home that was confronted with sliding down the yard into the lake. A shed had already slid to the water's edge; lately, it could be seen attached by strong lines to keep it from getting dunked.

The yard was criss-crossed by large PVC pipes—perhaps for redirecting up-slope runoff. Bales of hay aren't the solution. Boundary lines between nearby homes are still turning into ravines.

The "fix" was to cover the entire yard with a huge coarse mat and buttress the shorefront with three rows of large concrete blocks: those interlocking blocks are normally used on steep slopes to support parking spaces for cars.

I haven't been over to the Broads-side of Wolfeboro Neck this year to see how that repair has fared.

I'll look for some others, but this photo was taken years ago, before the situation got extreme.

[tis]

That is all fixed now, Acres, and you would hardly know what happened. I felt so sorry for them. That is what is hard about a steep slope, not to mention walking up and down it all the time. I would hate the stairs! Good exercise though. You might as well look at the bright side, right?

[ApS]

Lake Guy: I'd suggest moving some bread-basket-sized rocks in a large semi-circle around each of the affected concrete bases. Inevitable down-slope movement of forest duff, earth and clay will fill in the areas above the rocks. "Stake" the rocks with wood or rebar. Wood will last long enough to stabilize the rocks. The bigger the circle of rocks giving support, the stronger the support.

I've found several more photos in my computer! They'd been unaccountably filed under "Erosion".

Originally Posted by tis

That is all fixed now, Acres, and you would hardly know what happened.

1) About "all those stairs"—you're right! A family I know—and you may know them too...think "Marcie"...are approaching their 70s. They've just bought into a similar access of stairs—directly in my view of Lake Winnipesaukee.

2) I don't know about "fixed".

Many shrubs, many stumps, and many square yards of clay washed into the lake over a decade. I have photos of that slope going back twelve years—they couldn't be that ignorant of that condition all those years!

All-fixed?

[ApS]

Originally Posted by tis

That is all fixed now, Acres, and you would hardly know what happened.

1) The erosion "repair in progress" appears at my previous post.

2) Although a mile of that SW-facing shoreline remains in peril from runoff, here's that same property today.

It took weeks of installing concrete blocks along the shoreline, and the spreading of mats up to the house. That we can see, the soil that remained has finally been stabilized:

[Natt]

Originally Posted by Acres per Second

1) The erosion "repair in progress" appears at my previous post.

2) Although a mile of that SW-facing shoreline remains in peril from runoff, here's that same property today.

It took weeks of installing concrete blocks along the shoreline, and the spreading of mats up to the house. That we can see, the soil that remained has finally been stabilized:

This is just why the Shoreland Water Quality Protection Act is so critical for the lake and the regional economy.

[Rattlesnake Guy]

I was thinking about the original question last week and was thinking about how bad it would be if you added concrete around a post above the frost line. The frost could lift the cement and the post with it.

[ApS]

Originally Posted by Natt

This is just why the Shoreland Water Quality Protection Act is so critical for the lake and the regional economy.

I stumbled onto a photo I'd placed on this forum several years ago.

At the bottom-middle of that photo, it shows my dry right shoe beneath the roots of an approximately 50-y.o. Maple growing directly at the shoreline. (Really, that tree was "suspended" above the lake. )

Yes, that shoe has my foot in it!

That Maple grew from a seed that would have started about two feet above the pictured lake level. As this is an undeveloped lot, erosion had claimed all that lakefront soil into the lake.

I looked for that tree on Thursday, and discovered it's nowhere to be found!

[Jonas Pilot]

If you look at the image in post #5 you can see proof that the Shoreland Protection Act is needed.

[tis]

Originally Posted by Jonas Pilot

If you look at the image in post #5 you can see proof that the Shoreland Protection Act is needed.

How do you think the shoreland protection act would have prevented that "landslide"?

[Jonas Pilot]

Do you see any land slide where all the trees weren't cut down?

[tis]

Before the landslide, there were trees. They hadn't cleared it out as far as I can remember. THe trees went too as they are going in other places. When you have a steep hill like that, I don't know if anything can stop a possible landslide.

[Jonas Pilot]

Originally Posted by tis

Before the landslide, there were trees. They hadn't cleared it out as far as I can remember. THe trees went too as they are going in other places. When you have a steep hill like that, I don't know if anything can stop a possible landslide.

Please check the image in post #3. It shows clearly the extent of the tree removal.

[tis]

I won't argue with you except to say this. WE don't know when that tree in the picture was cut, before or after the slide. I do not recall that land being stripped. Even with the shoreline protection act you can cut a FEW trees. When land is that steep, even with trees, it can slide.

[Jonas Pilot]

I guess you'll see what you want to see.

[ApS]

Originally Posted by Natt

This is just why the Shoreland Water Quality Protection Act is so critical for the lake and the regional economy.

You are correct.

Erosion adds silt and unnecessary "nutrients" into the lake—contributing to the recent algae growth that spreads the dreaded "Duck Itch". Runoff from all steep lots forms an ideal substrate for the spreading of milfoil and other "invasive-exotics".

In a previous photo, you can see at least one stump was left in place, but even those "required" stumps weren't sufficient to hold back the landslide. This was a heavily-forested shoreline when I was growing up here. It depends on one's perspective, but trees get cut down—to "improve the view of the lake".

Though long-delayed at that site, the first mitigation attempt was the erecting of the usual "soil fences":



You can see how that worked out.

In the lakefront lot next door to me, a leachfield got a wash-out a few years ago, and appears as a moonscape

Septic-PVC appear as the white objects in the photo.



There are many more photos of Lake Winnipesaukee erosion in this computer—taken just by me—but I think I'll stop about here.

[Onshore]

Slope failures are going to happen. Erosion, slumps, slides and the like are all natural processes than can't be prevented forever. That said there are certainly things you might want to avoid doing if you happen to own steeply sloping land and you don't want to increase the risk of these events. First off don't be ignorant about the ground under your feet. Know if there is shallow bedrock or if it is mostly sand or clay. Second, don't cut out all the small vegetation and keep just a couple of large trees on the slope. Mixed stands of vegetation will hold a slope remarkbly well at no cost to the owner, however the key is having "mixed stands" vegetation. Isolated large trees can actually become a hazard because of their exposure to the wind. A large tree swaying in the wind can be analogous to some jamming a pry bar in behind a rock and working it back and forth. Stands of trees are not likely to behave this way but individuals can. At the first signs of slope failure the tree should be removed and new woody-stemmed vegetation planted in the vicinity. Lastly, irrigation systems... If you believe you absolutely have to have one for some reason, use only the water that you need. Extra water pumped directly into the soil means extra weight, extra pressure, and extra mobility.