Delayed Paving Drainage Problems 1

[heide]

We design many developments which are built in phases. Often the client wants to delay paving the top course of HMA until after most or all of the construction traffic has stopped. It can sometimes be upwards of a year or two before the top course is finished.

Has anyone found a good way to deal with drainage problems that result from have a 1 1/2" to 2" lip at the the edge of pavement/curb interface, thereby leaving ponding and rendering on-grade basins useless?

We have tried leaving the curb-line catch basins at leveling course grade and adjusting them just prior to paving, however this gets messy, what with the pavement and curb replacement.

Any help would be appreciated.

 

[Maury]

I have the sonewhat same problem. In fact, the City requires a delay so that problems in the base can be identified and corrected before placing the surface course. I haven't seen that the ponding areas you describe have a greater frequency of problems than anywhere else. The Owner has to accept this as a cost of doing business.

 

[cvg]

can you leave one basin open (at leveling course elevation) at the sag so you get complete drainage? spread should not be a problem since the road is probably not open for traffic yet anyway. You can also install a construction subdrain in the side of the basin to take the flow during construction and then plug it when you finish the paving.

 

[gbam]

Does your project have Storm Water Pollution
Protection BMPs? Typically in my area, the CBs are protected with sed logs or bails to limit the sediment entering the storm sewer. This in turn creates ponding issues during construction. I have seen these BMPs in place for over a year for larger projects. Is a couple of inches of ponding that much of an issue? Where are you located? Is precip high/often? If the ponding is an issue maybe interim drainage facilities should be used, just a thought.

 

[heide]

The road actually is open to traffic in most cases. This is typically required during phased construction for base issues as mentioned, as well as to prevent construction traffic from beating up the new pavement.

The ponding occurs at sag inlets, where the water is required to pond to the same depth as the lip before it can enter the basin.

During temporary situations such as over the winter, ponding is not such an issue. However in subdivisions with several phases, often built months or even years apart, the ponding can become quite a nuisance.

We have used the adjacent underdrain solution and have had problems with them plugging with debris and snow, so I wondered if there are any others out there, possibly proprietary.

Thanks for the help!

 

[PELS]

If it's feasible in the site and street layout, we try to provide a separate and temporary "construction traffic" access point to the project. Sometimes this can be a dirt road and sometimes it may need to be gravel or temporary pavement but it diverts the heavy construction traffic away from the newly paved streets. Some jurisdictions require this with the SWPPP and call it a "construction entrance". It depends on the particular site constraints whether or not this is feasible for your needs and you have to do a cost comparison of a temporary road versus repairing pavement and base course in new streets.

 

[bws2]

I also have these similar problems. We are required to do the final 1" overlay of the asphalt at project completion.

I find that the majority of the problems are due to bypass from the upstream catch basins or a road that is proposed to be built in a future phase uphill, which would collect and pipe runoff that the sag catch basin is not designed to handle as overland flow. The complaints we get are from homeowners who are concerned about seeing this much ponding in the street. We have had some success (temporarily) with installing washed stone logs wrapped in filter fabric and placing them on the downstream side of the 'on grade' catch basins to create a ponding effect at the upstream catch basins - But the homeowner's don't like to see this either.

I agree with Maury when he says "I haven't seen that the ponding areas you describe have a greater frequency of problems than anywhere else. The Owner has to accept this as a cost of doing business." But if this is a common problem and your concerns are about the depth of ponding maybe you could consider over-designing the sag catch basins to account for this.