Swales

Hi everyone. I am looking for advice as to how I can slow erosion on my property and incorporate that into the landscape. I have a few goals, on of them being growing some of my own food. I have read and watch videos about building swales and planting trees, bushes etc. on the other side of the swales. All advice will be appreciated as well as any good book on permaculture that has practical ideas to implement. I have a few questions in mind. How long do the swales have to be, depth, width? How far apart should they be from one another? Any other ways you have tried to stop erosion are also welcome. I am attaching a few pictures of the slopes with the slope percentage (which I calculated) so you can get a better idea of what I will be working with. BTW all these water goes on to a seasonal creek which runs though the entire property, which is also causing erosion because it slopes north to south. Maybe I can build some kind of pond system (permit required? dont ask/ dont tell? Any how that might be part of a different thread. Thank you in advance for you input.

THERE are a few questions before we can answer
What area are you in?
hat soil type do you have?
rainfall annually?
How big is the area you are speaking about?

Great books on swales, water catchment and erosion control are Rainwater Harvesting for Drylands and Beyond by Brad Lancaster vols 1 and 2. https://permies.com/wiki/51855/Rainwater-Harvesting-Drylands-Brad-Lancaster

John C Daley wrote:THERE are a few questions before we can answer
What area are you in?
hat soil type do you have?
rainfall annually?
How big is the area you are speaking about?

I live in California. The rainfall average in Valley Center (where I live) 15” per year, but we have had more rain this year.
The area across the slopes is about 3/4 acre. Clay soil.

Ok, thats a great starting point
Clay soil holds water
I dont see why your seasonal creek would cause erosion because it flows north to south.
Creeks cause erosion because of speed of water, soil type etc.
using terraces as well as swales on your block, may work better.
Terraces will give to flatter surfaces to work on, and swales will catch and hold water so it soaks into the ground.
If you look up Natural sequence Farming in Australia you will get some ideas, although they are more suited to large tracts of land.
By constructing walls across the creek, so that the toe of one 'pond' lines up with the top of the next wall, you could slow any flow down a lot and retain that water in the ground as well.
Any walls will need to be covered with rock to prevent erosion.

You will ned to plan roadways, housing, shedding etc all at the same time.

Until you decide how much disturbance to introduce, how much reshaping to undertake, you can implement low cost short term solutions.

Like cover exposed areas with wood chips and sow a drought tolerant cover crop. If you have woody debris or even left over firewood, you can arrange above and below eroded spots, pounding in small brances like spikes to hold debris in place. You can do short term check dams in your creek with firewood and clay. Nature abhors bare ground and has many means of avoiding it from weeds, vines, leaf litter, etc. We can mimic nature to let the healing begin.

Swales might work for you but a simple solution such as a vetiver hedge might be just as effective.  It just depends on what your long term goals are.  It would definitely stop/slow the erosion.  Switchgrass might be another solution.  As far as the stream goes, check dams or small rock dams could be an answer.  Once again, a really simple solution that can have excellent results.  It is less labor intensive than a pond and can be tweaked until it fits your needs.

Here's a Calculator that will help you decide:

input your numbers and let it rip :)

https://www.permaculturereflections.com/swale-calculator/