I bought my house a few months ago and have noticed a long and narrow strip that is mostly bare of grass in my backyard. I have no idea why it is there, but recently I found what looks like a plastic drain hole along that strip. See pictures below. What is it, and why is it there? What should I do about it?
I believe that's a daylighted drain pipe. Before I began capturing rain in rain barrels at my house's downspouts, I ran a piece of drain tile from the downspout away from the house and "daylighted" it down the hill a bit from the house. This effectively moved the water coming off the roof away from the foundation and allowed it to run out into the yard 30 feet or so away.
My guess this is a similar setup. It doesn't always have to run from a downspout. It could be part of a drain system.
Sometimes rain gutters are run to underground dry wells. Basically a hole lined with a tub filled with gravel that allows the water to drain down into the soil. The ones I've seen have a popup overflow.
I've never seen one that has holes like yours. My guess would be either someone didn't want to run the underground pipes and just put a drain cap. Or maybe that area of your lawn is lower than other areas and pools with water when it rains so they put a drywell with a drain there to get the water down into the soil so it doesn't get muddy. Or I could be wrong and it's a drywell connected to the downspouts with holes instead of a popup.
It's most likely some sort of drywell but whether it's for your gutters or for drainage due to grading problems it's hard to tell without seeing photos that show it in context.
It is there to protect your backyard from flooding in case of heavy rains. The ground must be sloped towards the drain so that all the water flows in that direction and goes out to the front of the house (on the street) or straight to the drain.
