Sidewalk drainage between buildings
Sorry in advance for the long post, but I'm hoping to tap into the expertise here. I am handling some maintenance for the townhome community I live in. We have a drainage problem between two of our buildings.
The buildings are about 40 feet apart, with a sidewalk running between them that residents use to get from the parking lot down to their units. The landscape from each building is slightly sloped down toward the sidewalk, and the general slope is downward from the parking lot toward the far end of the sidewalk. The total sidewalk run is about 200 feet from the parking lot down to the last units, with another 50 feet or so past that before the landscape really drops off toward the street. The problem is that the slope is not consistent and there are several areas along the sidewalk where ponding is an issue. In the winter this is particularly bad as we have sheets of ice covering the sidewalk.
The total square footage of roof being drained into this area is around 4200, coming from 4 downspouts on one building, and 3 on the other.
I've discussed the issue with the board of directors and am tasked with presenting a couple of possible solutions to address the issue before heavy spring rains start up. Right now I've got two ideas I'm working with and I'd like to present them here for some feedback.
Option 1 is to remove the existing sidewalk in its entirety, and replace it with a slightly wider sidewalk that integrates a channel drain (something like this: http://www.ndspro.com/trench-drains-and-channel-drains/channel-drain/pro-series-channel-drain-system) on each side, to catch runoff from each of the buildings. In my opinion, this would offer the cleanest look, but would also be the more expensive of the two options, and would have the greatest inconvenience to residents, who would be without a sidewalk for at least a few days. We would most probably hire this out as we do not have laborers with concrete experience.
Option 2 is to install a french drain on each side of the sidewalk. I'm thinking along the lines of 4" perforated PVC, buried in a 10" wide x 12" deep trench lined with landscaping fabric, and filled in with a 1.5" gravel of some kind. I think the best option for optimum drainage would be to top the trench off with decorative 1 to 1.5" stone, such as Colorado river rock, in a sort of irregular "wavy" pattern on each side of the walk. We have laborers that can do most of the work for this task, making it less expensive. It is also less inconvenient for residents.
I'm under no illusion that in a torrential downpour either option will completely handle all of the runoff we're dealing with. Our goal is to handle water from the more frequent small showers, and to drain the water that normally would be left standing.
Do these sound like feasible options? Which sounds like the better solution? Am I missing a more obvious solution?