Much of the water does NOT get to that swale, though, so the primary strategic need of landscaping here is to manage the flows of all that water "on the run." The aim is to convert regular washout catastrophes into occasional annoyances.
Here is a diagonal swale we made in the lawn when we saw how storm water found its way from the rain spouts on garage side of the house down to the lake. Our contractor laid pipes to carry the outflow from the rain gutters under the lawn to a discharge point just below the feet of the bird bath. From there it runs down a gentle groove between the flower beds into the lake.
To the right of the channel is an area for our daylily seedling beds. Last spring we added metal edging to define all the beds and to deflect water. Now we are adding lines of brick to help us develop a slight terraced effect in each strip of seedlings or paths. The paths will be covered with cypress mulch. Some of them were done last year. Now that the scheme has proved effective in the upper section, we will carry it out in the lower section.
Where'd we get the bricks? I imagine they are the former owner's patio. I found them tossed or arranged in the main drainage swale on the left side of the property, part of the mound of rubble that prevented storm water from staying in the channel. So I tossed 'em aside, one by one and chunk by chunk until the channel held the water. Then we stacked them and waited for a way to use them. We have recycled what I called "The Hidden Lake Rubble Museum."