We rented an end unit townhouse in a planned community adjacent to an empty commons area space and a visitors parking area. Today, the parking area is being shut down and a basketball court is being installed. The basketball pole is being placed into the ground adjacent to our property. Our landlord claims no prior knowledge of this development. We find it hard to believe the Homeowners Association didn't send a letter to property owners advising them of the new play area and subsequent loss of parking spots. The ample parking situation and quiet commons area were the reasons we rented this townhome. The posted play times are 9am to 8pm which will definitely impact our quiet enjoyment of the property. Are we justified in breaking our lease?

Not as far as I know. THe landlord isn't responsible for actions the Association takes on common property which you are not paying to rent.

The Landlord has violated no terms of your lease.

All you can do is when the lease runs out... find a new place to live or negotiate to reduce the rent you are paying at that time due to the changed amenities.

... Our landlord claims no prior knowledge of this development. We find it hard to believe the Homeowners Association didn't send a letter to property owners advising them of the new play area and subsequent loss of parking spots. ...

Maybe. Maybe not. But in either case it is unlikely that the LL had the ability to alter the decision.