Showing posts with label Stormwater Management. Show all posts
Showing posts with label Stormwater Management. Show all posts

Sunday, March 22, 2009

Rain Rain Rain


For the past week or so we have experienced the first signs of Spring (temps in the 50's, grass showing through the snowmelt and college kids wearing t-shirts and shorts outdoors) we are getting our rain barrels cleaned up and ready for action.

We collect rainwater. We use it to water our gardens (tomatoes and basil grow much better with rainwater than treated tap water) and trees, and any excess gets diverted to our raingardens so that stormwater infiltrates back to the aquifer rather than being sent down through the storm sewer system and into the mighty Mississippi River.

You may recall that we also installed a green roof system (see our post in October, 2008 for more info) to help manage stormwater, among other benefits.

So how much difference do our actions really make? Well, we've been measuring, and while we only have a few months of collected data - we can tell you what we know to be true at this point (stay tuned for updates).

Our total rooftop area is 1,724 square feet and will generate approx. 1,077 gallons of stormwater during a 1" rainfall. Left to its own devices, much of that would find its way elsewhere, and eventually to the river. But the data we collected between July and November of last year suggest that our rain barrels collected some 48% (16% used of for irrigation, 32% diverted to raingardens) or a little over 5,400 gals of water. Our green roof absorbed some 12% (1,200 gals) of the total rainfall at the rooftop for that same period even though it was only in place since October. So, during the 5 months we were able to measure, we diverted 60% of the rainfall at our rooftop from moving across our lawn and into the storm sewer system and river. I expect this number to increase significantly when we have a full year's worth of data and a full year's worth of green roof performance.

That means that if everyone utilized a rainbarrel at one or more of their downspouts we would save enormous amounts of stormwater, sediment, chemicals and fertilizers from entering our lakes and rivers; our recreational waters and our drinking water. That's healthier for everyone. It also means less water being treated by our local governmental water treatment facilities, which saves us money and keeps our waterways beautiful and usable.
We'll report more when we know more! Next up, a post on our energy use. There have been a few unexpected twists and turns as we've measured and monitored our consumption.

Thursday, October 2, 2008

Power Plants on the Roof


Hello one and all - yesterday was a red letter day for the HAUS - we installed our green roof (800 sf in 6hrs!) and it looks amazing! For those of you who'd like to know, we used a vegetated roof system called LiveRoof. It comes in preplanted modular trays (1 ft x 2ft by 4" deep) with native plant species selected for your specific exposure and microclimate.

Our roof used 2 different plant mixtures -
Classic Carefree Sunny Mix
Sedum Album (Coral Carpet)
Sedum hybridium(Immergrunchen)
Sedum reflexum (Blue Spruce)
Sedum rupestre (Angelina)
Sedume sexangulare
Sedum spurium (dragon's blood)
Sedum Neon
Allium Flowering Onion

and
Shade Mix
Sedum Pachylados
Sedum hybridium(Immergrunchen)
Sedum spurium (Fireglow)
Sedum rupestre (Angelina)
Sedume sexangulare
Sedum spurium (Green Mantle)
Sedum Spurium (Royal Pink)

These plants are carefully selected to handle lots of rain but also do well for long periods without rain in our Minnesota climate. They will grow to be between 2 and 4 inches tall -and besides periodic weeding will require very little maintenance.

I like the Live Roof system because it comes fully planted and ready to rock and roll. We ordered the plants in early June and the nursery did most of our work for us - growing and caring for the plants all summer long before harvesting them for us this past week and prepping them for our installation. Now that they are on our roof, we don't need to be watching bare dirt with a few plant plugs watching and waiting for them to grow - it's an instant green!


Boy, You Crazy! Why you want a green roof?
Green Roofs help:
  • Manage stormwater (up to 95% of rain fall is used by the green roof)
  • Reduce Energy Costs (energy use reduction of 25% and higher)
  • Extend the life of the primary roof system by 200% (protecting rooftop from temperature swings, ultraviolet radiation, etc)
  • Noise Reduction
  • Improve air quality
The Live Roof system costs about $12.00 per sf but will vary depending on the size of your order. We installed it ourselves and so saved a lot on labor costs. We worked out the details and became certified green roof installers through our local Live Roof supplier - Bachman's nursery.

Here are some photos of the installation in progress:

The plants arrived via truck and after unloading are ready to be brought up to the rooftop.


We rented a scissors lift to help move the modules (about 50 lbs each) up to the rooftop. There was no way I was going to carry 400+ roof modules one at a time on a ladder. The plywood on the ground helps protect the newly planted lawn.



Even local celebrities get in on the act. Here, the famous Curt Kietzer carries the first of many modules to it's final destination. My brother Brian is working the lift.


Getting Started - all the modules click together to stabilize each other and promote better plant growth. The green soil elevators keep the soil in place until they are installed. Working from right to left, we filled in the rooftop pretty quickly. You can see the dark grey 45 mil epdm slip sheet we used as root barrier on top of our real roof membrane. We don't want the plants messing with our roof membrane!


Jeffrey Swainhart is the man with the saw cutting the modules at the end of each row to ensure a tight fit. Cutting takes a long time and should be minimized!


Regular sweeping is critical to avoid pinching any sharp aggregates between the plant trays and the roof membrane.


Curt K and Guy Williams seen splicing the joints at the metal edging - I favor the edging over the cutting .







When the upper roof was nearly complete, we started in on the lower roof (Shade Mix)




Lower roof complete



Upper roof complete


A nice detail so my ladder doesn't damage the plantings on the lower roof when I need to access the upper roof. The pavers are recycled rubber porous paver systems called VAST from our friends at Natural Built Home.

We've been measuring how much water our rooftop generates during each rainfall (we're collecting runoff in rain barrels). Now, with the green roof in place we can track the reduction in that amount. Rather than sending our runoff to the stormsewer system and thus to the Gulf of Mexico via the Mississippi River, we're using the rainwater to keep our plants healthy and happy so they can do all those good things for our home.