Get Involved – Best Practices

Property Maintenance Manual

The Education and Public Outreach Committee of the Shingle Creek and West Mississippi Watershed Management Commissions has prepared a booklet detailing Best Management Practices for Commercial Properties and Common Ownership Properties (found here). This guidebook is designed to help property owners better understand:

Ø      How to inspect and maintain their ponds and drainage systems to ensure they function as originally designed

Ø      How to specify turf maintenance and plowing/ice control contracts that minimize runoff of pollutants to our lakes and streams

Ø      Eight simple things they can do to improve water quality

 

Rain Gardens

What is a Rain Garden?  A rain garden is a strategically located low area planted with native vegetation that intercepts runoff.  Rain gardens help rainwater and snowmelt to infiltrate naturally into the ground rather than run off your property into the storm drainage system.

 

What makes a garden a rain garden? In many ways, a rain garden is indistinguishable from any other garden.  The main difference is that, rather than planting in a bed that is flush with the ground or raised, the bed of a rain garden is 4-6 inches below the level of the ground.  Many different types of shrubs, trees, perennials, and annuals thrive in wetter soils and are suitable plants for rain gardens.

 

How do I build a rain garden?  A rain garden can be as informal or as engineered as you like.  For best results, excavate 1-2 feet down to decompact and loosen the soil.  Unless your soil is naturally very sandy, work in sand to achieve a soil mix of about 50% sandy soil, 20% organic matter, and 30% topsoil.   The floor of the rain garden at its lowest point should be 4-6 inches below the ground level.  Slope the bed gently towards the low point of the garden.  The City of Maplewood, MN has more information on different types of rain gardens.

There is no standard size for a rain garden.  It should be large enough to contain the water from the area draining into it without overflowing and the water should infiltrate within 4 to 6 hours.  The size of the rain garden should be anywhere from 5-30 percent of the size of the impervious surface draining into it.  It may take some trial and error to determine the right size for your garden.  Many properties drain in several directions, so instead of one big rain garden you might be better off with several, smaller gardens or a combination of rain gardens and rain barrels.

Place your rain gardens near impervious surfaces so that rainwater and snowmelt will drain into the dip or depression. The gardens should be located strategically near impervious surfaces such as patios, sidewalks, driveways, and under downspouts or gutters to capture the rain as close as possible to the point where it falls. Rain gardens should be planted at least ten feet from your home’s foundation to avoid basement seepage.

 

What do I plant in a rain garden?  Many hardy shrubs, perennials, and annuals thrive in wetter soils.  For more complete information, see the University of Wisconsin’s How-To Manual on Rain Gardens. To request a hard copy of the manual email us at judie@jass.biz. 

The Friends of Bassett Creek have also produced a pamphlet with useful information about rain gardens including lists of good native plant choices.  Visit their website or the Twin Cities Green Guide for more information.  Additionally, the Rice Creek Watershed District recently started a program to aid people in creating rain gardens.

Shredded hardwood mulch over the surface will help keep down weeds and prevent erosion.  Rain gardens require the same routine landscape maintenance such as weeding, pruning, plant replacement, mulching, and supplemental watering as your other gardens.

 

What about mosquitoes?   A rain garden is not intended to detain water for long periods. Mosquitoes will not survive in wetlands that dry out in less than a week after a summer rain. The development of a mosquito from egg to adult takes 10 to 14 days. A mosquito larva must live in water for 7 to 12 days before maturing to the adult stage.

Rain Barrels

What is a Rain Barrel?  A rain barrel is a collection system that stores rooftop runoff to be used later for activities such as lawn and garden watering.  Collecting rainwater from your roof by using a rain barrel can not only help to decrease water demand during the hot summer months, it also helps reduce stormwater runoff and increase infiltration.

 

How does it work?  You can purchase a rain barrel at many major lawn and garden centers; many on-line retailers also carry a variety of rain barrels.  You can expect to pay $80-150 for a 50-75 gallon barrel and accessories.  If you’re feeling creative, you can build your own rain barrel out of a 55 gallon drum or trashcan.  You can also link rain barrels in series to store even more rainwater.

 

How much rain does it take to fill my rain barrel?  Not as much as you think.  It is easy to calculate how much rainwater your roof generates. The constant to remember is: 1" of rain will produce 625 gallons of runoff from a 1000 square foot roof, or 625 gallons per 1000 square feet.  

Say you want to install a rain barrel to catch runoff from half the roof of your double garage.  Let’s say that eave and downspout catches runoff from 250 square feet of roof.  Multiply 250 square feet by 625 gallons and divide by 1000 = 156.25 gallons produced from a 1” rain.  A ½” rain will fill up your 75 gallon rain barrel.