Monday, December 22, 2014
Stormwater Management (12/21/2014)
What, no location on this post? My back yard, Yorktown or even Newport News Park would be a decent heading as well, but this post is more than that. It speaks more to one of the things I like to do (landscaping, architecture, building, paving) and things I teach (stormwater management).
Over the past two weekends we decided that a strip of grass between two paved areas in our back yard was more of a bother than an asset. The few things it was good for was that it had some clover (good for bees) that sometimes did reasonably well early on in the year, and that it is the area that receives the overflow from one of our rain barrels and thus serves as an infiltration area for water coming of our roof.
That water infiltrates into the soil is a very important thing to me. I give impassioned talks about this subject in the classes that I teach and talks that I give throughout the state, in particular since we are definitively seeing a drastic drop in groundwater tables in areas that are developed. Areas that are turned into subdivisions and shopping areas become less pervious to rainwater than the forested area or agriculture land they were before development. Rain falls onto impervious surfaces (roofs, roads, parking lots, etc) after which it enters some form of stormwater management system and is piped into the nearest stream or river. As a result, rainwater that used in infiltrate and recharge our groundwater tables now runs down ditches into a river and out to the sea, or in our case the Chesapeake Bay. All this added water in the streams also causes flooding downstream and more erosion in the streams during rainstorms while in dry periods the streams are drier than they used to be. In essence, building subdivisions is not the best for our natural environment; although it is a necessary thing to do; we need to live too. But I believe in sensible development and less urban sprawl (search my blog for the label urban sprawl and you'll see what I mean).
What I teach is also known as Low Impact Development. Yes, we need homes and subdivisions, but we can build them sensibly, with respect for our natural environment and for the ground water resources. When we do that we alse take care of the water quality and quantity in our creeks, rivers and streams. Instead of piping the water away, we need to help it infiltrate with things like rain gardens, bioretention permeable pavement and other measures. That was what I was looking at when doing my paving job.
In this job, I used all kinds of recycled materials. When we lived in Cincinnati my wife and I would even clean up the Ohio River and pick up old brick that were dumped along the river. In this job, the tiles were from a walk way we took out and the brick are all recycled from old building projects (my wife and I spent long hours chipping away the cement that clung to some of these brick).
Giving the brick and tile a bit of a grout line will help with some water infiltration; but we had to deal with the overflow from our rain barrel. Luckily we had what I call holy brick, or brick that is uses as veneer to a home. These brick all seem to have three holes in them (hence the holy in holy brick). So we constructed a slightly depressed channel of these holy brick between the tiles. We routed the water from our rain barrel through this channel in the hope (expectation) that any overflow will infiltrate through these holes into the soil; thus achieving what I teach: runoff reduction. We will have to monitor it and see how it works. The photo below show the results of a two-weekend job, minus the sore back.