January 23, 2013 at 3:01 pm #155627
Does anyone know of any stormwater management courses a non-engineer could take to become knowledgeable about calculating whether or not daylighting (i.e. bioswales, detention ponds/sediment basins, etc) is feasible?
I’ve run into the problem at work a few times now where I discuss with the engineer using bioswales instead of pipes, but then when they go off and do the grading plan, the pipes show up again a couple weeks later. I think 85% of the time this is due to them just doing something easy and what they’re used to, and not because the bioswale is unfeasible. It’s also much more expensive to pipe things and add manholes etc.
It would be really great to be able to have some hard knowledge beyond theory to quickly bring back to the engineer to show the reasons why it would work.
Are there any courses or certificates out there that would teach us this stuff?January 26, 2013 at 4:27 am #155631
Unless the municipality is requiring retention/detention ponds, or stormwater treatment of surface contaminants, you’ll be on the losing end of the arguement for quite a while.
You might also talk to the bosses – they may be quietly pushing the engineers back to the lowest liability solution. Construction costs and long term maintenance are not always a factor for many projects, but immediate profits are.
And since you’re in a town with a really good university, go talk to the Engineering Dept about the hydrology and water management classes they offer. Getting beyond the math curve can be daunting if you’re trying to do this on your own.January 29, 2013 at 1:21 am #155630
Is it an underdrain? They are typically used for bioretention cells, bioswales, etc. It is not a negative. They are used to dewater the soil in the event that the other dewatering techniques (infiltration, evaporation, evapotranspiration) won’t dewater the swale or rain garden (bioretention cell) in the 48 hr period (thats the dewater time here in MD, based on HSG)
See:January 29, 2013 at 2:06 am #155629
I would suggest getting a free subscription to this magazine: http://www.stormh2o.com/SW/SWhome.aspx
and try to at least get familiar with the terms and current topics. Getting more overland flow and infiltration is a “hot” topic in some states that have legislation calling for storm water solutions that reduce pollutants and overall volume of flow off of a site, so there are people interested in bioswales from that perspective. With performance standards that state merely that rainfall hase to drain from a lot within x minutes, well, its harder to make the case for pollutant filtration.January 29, 2013 at 8:04 pm #155628
When I sat on the other side of the table (engineer’s side), the main reason we tended to lean towards piping was the maintenance of the bioswales (mowing, weeding, cleaning, and recommended replacement; some systems call for replacing soils every 5~10yrs, at least to get rid of fines/silt) which many clients are reluctant to commit to. Selling it as a benefit, by choosing nicer planting material and taking the time to make it have some curb appeal rather than a wild mess takes time (and fees), but often leads to an easier sell.
Most states have stormwater mauals available online that includes the equations and sample calcs to help you figure out how much rainfall a bioswale can take; they’re relatively easy to navigate.
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