How to Build a Rain Garden in Eugene, Oregon
How to Build a Rain Garden in Eugene, Oregon
Create a sustainable drainage solution that manages stormwater runoff and protects the Willamette Valley watershed by installing a functional rain garden.
What You'll Need
- Perc test kit or a bucket and water
- Shovel and garden rake
- Wheelbarrow
- Native rain garden plant mix
- Organic compost
- Mulch (shredded cedar or hardwood)
Steps
Step 1: Site Selection and Perc Test
Choose a location at least 10 feet away from your home's foundation and avoid areas with underground utility lines. Perform a percolation test by digging a small hole and filling it with water to ensure the soil drains within 24 to 48 hours, as Eugene's clay-heavy soils can vary significantly.
Step 2: Determine Drainage and Sizing
Identify the natural flow of water from your roof gutters or driveway to determine the garden's placement. Size the basin to handle the specific volume of runoff from your impervious surfaces, ensuring it is shallow enough to allow water to infiltrate without creating a permanent pond.
Step 3: Excavate the Basin
Dig out the area to a depth of 6 to 12 inches, depending on your soil's drainage capacity. Store the excavated soil in a pile nearby; you will use the best topsoil for the surrounding berms to keep runoff contained within the garden.
Step 4: Amend the Soil
If you have heavy clay soil common in Lane County, mix in organic compost and sandy loam to improve permeability. This creates a porous medium that filters pollutants from the water before it reaches the groundwater table.
Step 5: Construct the Berm
Use the remaining excavated soil to build a small, reinforced mound or berm on the downhill side of the garden. This prevents runoff from escaping the basin and directs water toward the center of the planting area.
Step 6: Select Native Plants
Choose a mix of native Oregon species that can tolerate both saturated soil and periods of summer drought. Incorporate a variety of depths, using deep-rooted sedges and rushes in the center and moisture-tolerant shrubs on the slopes.
Step 7: Planting and Mulching
Install plants according to their moisture needs, spacing them closely to minimize weed growth. Apply a 2-to-3-inch layer of shredded hardwood mulch to suppress weeds and retain moisture during the dry July and August months.
Expert Tips
- Avoid using river rocks as mulch, as they can float away during heavy winter storms.
- Check with the City of Eugene regarding local stormwater ordinances before altering significant drainage patterns.
- Focus on native species like Red-osier Dogwood or Slough Tera to support local pollinators.
See also
- The Best Local Bakeries in Eugene, Oregon
- Best Hiking Trails in Lane County, Oregon: A Seasonal Guide
- How to Build a Rain Garden in Eugene, Oregon
- Best Fishing Spots in Florence, Oregon: A Complete Guide