[Kasperspirit]

hi...

I hope i havent put this in the wrong section.
If so, plz some mod move it.

Anyway...
i am making my thesis design and it requires that we dig a trench from the river and make an artifical lake that branches in many directions somewhere in the forest.
I am looking for the technique how to do this lake with information of steps to follow so the river bank doesnt collapse and so that water doesnt infiltrate much to the deep because near this place is an archeological site and monuments must be far from water.

Can anyone help me with this.
thanks...

[tfld]

Im a landscape architecture student. From my limited experience I would say 3:1 max slopes on the banks if possible to deter erosion, avoid using rip-rap or stone on banks to encourage habitat, and try to think about blurring the line if you will between land and water and what happens during a flood event and a drought event. As far as high and low water, how can that encourage habitat and different types of plants and animals?

I'm not sure on sealing or capping the earth, I suppose it would largely depend on the soil composition whether its a clay or sand, etc.

In laying out the routing for your water courses you should try as much as possible to follow the existing contours, ie "natural lay of the land," and perhaps avoid putting water on ridges and hill tops. The streams should flow at a minimum of 1-2% grade (maybe more per agla's comments) which is perceptually flat, ie 2'-4' of drop for every 50' in horizontal distance.

Those are just a few things I'd consider.

hope it helps..

-n

[Kasperspirit]

thanks.
this helped me alot.
i even made searches acording to the data u informed me about and found it to be the best norm to follow.

i would like to ask something else.
in the research i am doing, i have read in many places that on slopes near the water, gabions are used.

do you know anything else than this, or is it really the best solution to use?

[tfld]

I'd say, from an aesthetic standpoint gabions should not be used and considered a last resort for slope stabilization. Gabions are typically constructed of "rip rap", what I talked about earlier. This is a pretty typical engineering solution, but does very little ecologically for the river and can substantially degrade the river and adjacent environment due to complex ecological principles I couldnt really get into here.

Also, if you think about it, gabions and the like are very poor way to treat a watercourse as it also inhibits humans and animals from experiencing/touching the water. Gabions should only be used in extreme cases.

If you'd be interested in ecologically sound practices and principles of slope stabilization and ecological design I would look at the book "Design with Nature" by Ian Mcharg. He was/is at the forefront of environmental design and re-creating healthy habitats and ecosystems.

[Hoosier]

contact your DNR and extension office.

[Paul]

Before excavation you drive sheet pileing along the bank and along the channel to be dug. Then excavation can begin. More info with greater info on project.

[Kasperspirit]

thanks alot for the help.

I will buy this book today... and i will tell you all more of the project soon.

EDIT:
My fault...
I should have mentioned this before.
in the design i a making, we are creating a new sacred space for people.
The objective is to create a wide landscape where varius religions of the world can come and use the field as a sacred space, primarly water being the important feature bcz the religions essence is in water and without it, these religons have no sense at all.

As for the gabion, i found that many Japanese/Buddhist gardens are being built this way.
well, maybe the book will have more answers to my questions...

Thanks again.

[Malrex]

I'm not a fan of gabions. The "cages" that hold the rock together can get worn away and start to jut out into the river--creating spear points basically for fish.
I would do 3:1 slopes if you can, or even 2:1 slopes. I would install erosion control blanket on the banks and have a rock toe or even a bio-log to help hold the blanket thats in the water in place. I would sprig the banks with willow sprigs and plant riverine plants. I'd make the trench curvy and you could add rock weirs to help stabilize the grade. I would also add fish habitat structures along the banks--rootwads, jutting logs, etc. if there is fish in the river that you are building the trench off of. You could add some hard points along the trench with boulders if the trench nears a monument or whatever...but I would definately use "soft" engineering techniques.

Sounds like a neat project.