With most of the work complete along the length of the new Silver Line Phase 1 metro line, the lesser elements of the project like landscape, hardscape, lighting, and maintenance access are becoming more visible. One scope item I wasn’t aware of was the implementation of new stormwater facilities within the median of Route 7 underneath the overhead rail system. Between each column the Silver Line incorporates bioretention and infiltration facilities that both control the runoff from the metro line itself, but also some of the runoff that previously was uncontrolled flowing off of Route 7.
I think the designers have done a decent job incorporating both function and aesthetics so far on the facilities. Combining the access path to each facility along with access to maintain the rail line itself was a smart move, killing two birds with one stone. While most of the access areas are currently asphalt topped, based on a few I have seen it looks like a more decorate gravel covering will be the final result.
I’m not sure how they are installing the gravel, whether by some sort of adhesive polymer spray or leaving it in a loose condition. If the latter, it could mean nuisance debris being transplanted onto the adjacent street from time to time.
For some background on bioretention facilities, they are small decentralized pockets of ponded water that control small drainage sheds by partially slowing (ie detaining) the flow so as to spread the total volume over time, and partially by infiltrating or absorbing runoff through vegetated intake (ie plants and soil recharge). They work pretty well if the areas that drain to them remain within capacity, and no individual facility takes on more than it can handle. It’s certainly an improvement over the complete lack of any stormwater facility previously provided on Route 7… something VDOT must have forgotten from their own stormwater handbooks last time they widened the road.
One thing we have mentioned before in posts, as the vegetation, grass, and canopy trees begin to grow into maturity the impact of the concrete piers will be reduced. You only have to take a look at new suburban roads to see how this occurs in other areas as well. Take a trip to any new subdivision and see how barren it looks with small saplings, but after three to five years the neighborhood looks established and the sense of scale is improved. The same will occur along the Silver Line, and combined with some aesthetic improvements like lighting and paint, as well as new high rise construction along the corridor, the “ugliness” of the concrete will be diminished and it will look more appealing.