Need help with slowing down water flow in swale
Hello Everyone. I have run into a situation in my new construction where I am having drainage problems. Not necessarily for me, but for my two neighbors. In trying to be a good neighbor I'm wondering if you have any ideas to help me out.
My property lies between two completed houses. The house to my right (off screen in the picture) was having some drainage issues on the front corner of my lot which is the back corner of their yard. They have trees planted and it is the low spot of their yard where the lawn slopes to. There is a bit of slope coming from their lawn towards mine, but I would only estimate it as 4' over Compounding the problem there is that the drainage ditch along the road there overflows it's banks and comes into both of our yards when there is a significant rain or snow melt. When the county inspectors saw the water there (possibly after being called by the neighbors) they required me to put a swale in my yard going from the front of my yard along the side and all the way to the back yard (light blue in the drawing). Not something I really wanted, but hey... life, lemons, lemonade, etc..
My plan was (in the future when money grows on trees) to make the swale into a dry creek bed with river rock and boulders. All draining to a large pond at the end of the swale (to be built later as well). The pond would probably be roughly a 20' by 30' oblong shape. Also along the swale I planned to put in a culvert and road so I could reach the far back corner of my lot where I will build a shop and vegetable garden.
The swale is in now minus any landscaping or rocks and after this springs snow melt the water was running sometimes over 8" deep all the way to the end of the swale and washing out the dirt in the neighbor to my left's tree line. The big culprit, in my opinion was that the ditch along the road was draining through my swale and not through the developers planned drainage to the north (left in the picture). You can see in the plot picture that the easement has drainage heading between two lots to the north of me. Either way, I want to be a good neighbor and try to slow down the velocity of the drainage in the swale and had a few ideas I would like to run by everyone.
First, I wonder if putting landscape fabric down and then small gravel in the bottom of the swale (larger rocks on the side and then a few boulders interspersed as well) would slow down the drainage or speed it up?
Second, If I were to put in a smaller depression/mini pond along the swale's path before a culvert and road crosses it would it slow it further?
Finally, could anyone verify that the pond as a catch basin at the end would be a good solution?
I'm hoping that by landscaping the swale now, unfortunately as an unexpected expense, and following it up with a call to the developer and county regarding the ditch flowing through my yard and not their designed location will be enough to fix it.
Any thoughts on this and also how to landscape/plant along the swale would be appreciated.