Civil engineers design them, landscape architects loath them, developers wonder why we need them and municipal engineers often require them - I hate them. Retention and Detention ponds have become the standard for stormwater management on commercial and residential projects throughout most of the US. They were originally intended for flood control and were later incorporated into water quality requirements as well. They serve in their capacity to attenuate peak flows from new development reasonably well, but their usefulness stops there. Here are a few of the reasons that I'm not a fan of detention/retention ponds:

I have been advocating for and designing green infrastructure and LID solutions for a number of years now. In those years one of the most common things I hear is "So what's it going to cost me?". The assumption is always that it's going to cost more, and often they expect it to cost a lot more. Fortunately, its often less expensive rather than more expensive. This is especially the case with civil engineering (stormwater infrastructure, grading, parking lots, landscape design, etc.). Clients are naturally incredulous when I tell them that it's going to cost less, so their next statement is usually " Really!?, how much less?". In answering that question I have found that "well, that depends", doesn't always fly, so I have put together some general cost comparisons for several green vs traditional design elements.

“Assessing the conditions of the nation’s public schools remains a difficult process,” says the American Society of Civil Engineers (ASCE) in their 2009 Report Card for America's Infrastructure. The problem leading to this "D" grade seems to be funding. However, part of the problem is that we don’t know how much of a problem we have.

The American Society of Civil Engineers (ASCE) includes Levees on its 2009 Report Card for America's Infrastructure, giving them a D–. The category of "Levees" covers major flood control works. However, what about the water that causes the flooding that levees protect against? Throughout drainage basins comprising thousands of square miles, stormwater runoff makes its way downstream. Obviously some systems convey that stormwater and even control it. ASCE says nothing about these storm sewer systems, but they form a vital part of America's infrastructure.

Buffalo Township’s wastewater treatment plant is located along Buffalo Creek in Pennsylvania, beneath the State Route 28 bridge. This type of wastewater treatment plant is perfect to serve smaller communities. It supports 6,000 people with 3,100 sewer connections to homes and businesses throughout Sarver, Pennsylvania, and the vicinity. It’s an excellent example of an efficient wastewater infrastructure that uses extended aeration to treat raw sewage, without any initial sedimentation.

Reduce, reuse, recycle. This is the simplest mantra of the environmental movement and the guiding principle for families and small programs across the nation. How does this principle apply to infrastructure, specifically asphalt pavement? We already use as little asphalt pavement as we can, but this is more an economic decision. We recycle asphalt pavement to build new pavement. We reuse it as clean fill. What else can we do with it? Can we use it to collect solar energy?

The City of Takoma Park, Maryland, needed to replace a failing retaining wall that supports a roadway in a small residential development. The Linden Avenue site is directly adjacent to Sligo Creek, which is a tributary of Anacostia Creek, a river undergoing a significant restoration effort. T. E. Scott & Associates, Inc., designed a replacement for the failing retaining wall infrastructure, created a pocket park for the local residents, and provided water quality treatment for the unmanaged watershed. This combination of aesthetic and environmental improvements adds value to the project. We’ll look at some stormwater flow design calculations, a storm water flow splitter, an urban modular wetland unit, a step/plunge pool, and an interesting retaining wall design.

The various blogs I follow send me newsletters, and one article regarding new smart bridge technology caught my attention last Friday. A “smart bridge” is probably better labeled as a talking bridge – one that communicates its status to those who are listening for follow-on interpretation. Baseline measurements of critical strain, deflection, and corrosive conditions can be established with the structure following project completion, then monitored throughout the bridge’s service life.