Stormwater Starts at Home!

Jennifer SeamansManager, SW Watershed Resource Center

Overview

• What’s in a Watershed?• Clean Water Regulations• Stormwater Reduction Practices

• Stormwater Stars Workshops

What’s a watershed?(The land area that drains to a common body of water)

“A river is the report card for its watershed.” - Alan Levere

A Brief History of Time:Portland Geology Edition

n Fault lines causing both subsidence and uplift (e.g. the West Hills)

Depth and Age (stratigraphy): n Alluvial (in low areas) & landslide depositsn 16-12 ka: Missoula Floods (80)

à current Columbia flown 18 ka: Cordilleran Ice Sheet glacial silt (loess) n 1.5 Ma-500 ka: Boring volcanicsn Ancestral Columbia River and Sandy River

depositsn 15-13 Ma: Columbia River basalts n Marine sedimentary strata

Pre-Settlement Western Oregon

Multilayered canopy

Soil organic horizon

Nurse logs & stumps

Hydrologic Cycle

Impacts of Urbanization

EPA, 2003

Impacts of Urbanization§ Impervious surfaces reduce infiltration

and roughness, increase flow rate

§ More intense floods and droughts

§ Creek downcutting/incision

§ Increased sediments in runoff create problems for aquatic life

§ Soil compaction

§ Faster spread of invasive species

§ Loss of habitat connectivity and complexity: trees and canopy levels

§ Reduction in habitat for beneficial species

§ Increase in habitat for urban pest species

Why Stormwater?U.S. Clean Water Act

n Enacted in 1972 to protect public health

n EPA is the federal regulator

n In Oregon: state DEQ is charged with assessing water quality & issuing permits on behalf of the EPA

n Bodies of water that fail to meet standards become listed under CWA Section 303(d)

n TMDL: total maximum daily load

Stormwater Regulation in Portlandn Primary stormwater permits:

n National Pollutant Discharge Elimination System(NPDES), established under 1972 Clean Water Act for wastewater, point and non-point source pollution, and regulated by EPA. In Oregon, permits issued by DEQ.

n Municipal Separate Stormwater Sewer Systems(MS4), which further regulates NPDES stormwater within cities, depending on size (Phase I or Phase II). Portland and other municipalities must submit yearly compliance report.

Water Quality in SW Portland

n SW Portland creeks listed for:n Temperaturen Heavy metalsn Bacterian Phosphorus

n Stormwater runoff negatively impacts water quality:

n Rain picks up heat from asphalt, concrete

n Roads convey oils, brake pad lining dust (heavy metals), exhaust/particulate matter (PAHs), roof materials (zinc) to creeks

How do we Manage Stormwater?

n Slow it – Plants/canopy intercept rain before it hits the ground. Minimize flow off impervious surface (roofs or pavement), decrease harmful storm surges in the creek that cause incision.

n Spread it – To minimize erosion, increase evaporation and transpiration, and filter sediment & pollutants out of runoff so that they don’t diminish water quality.

n Soak it* - *only where it’s safe! Take it underground. Create stormwater storage in the soil and release it slowly following a rain event. Deeper infiltration recharges groundwater.

SW Texas Green Street and wetland

Portland’s Stormwater Systemn East side: Creeks are underground and

no longer visible. Downspouts historically directed rain into sewer. Installation of separate stormwater pipe and downspout disconnection began in 1991 and finished in 2011.

n West side: Stormwater flows along impervious surfaces, in roadside ditches along unimproved roads, and in open creek channel. Some separate stormwater pipes; few areas still with combined pipe (stormwater mixed with sewer). Runoff infiltration inappropriate for many/most sites.

n Big Pipe Project: reduced CSOs into Willamette River by 94-99%.

Combined Sewer Overflows (CSOs)

Open creek channel in blue

Portland

Stormwater System Challenges

n Continuing urbanization and infill developmentn increase in impervious area while depending on same systemn less land area available to slow, spread, store and filter runoffn more volume and flow into creek

n Maintaining level of servicen Stephens Creek Stormwater System Plan pilot (2013)n Moving forward: citywide stormwater system planning

n Weather extrema and climate changen Dispersed (non-point source) nature of stormwater à

need for education, outreach, and hands-on skills

Portland’s West Siden Loess (Portland Hills Silt, similar to

clay) n Poor infiltrationn Small particles = small pore spaces =

reduced volume

n Absorbs water slowly and releases it slowly

n Steeper topographyn Difficult to infiltrate due to surface runoff

n Increased soil particle mobility = erosion

n More open creek channel & erosionn Landslide hazard areasn High Groundwatern Site development challenges

Open creek channel in blue

Stormwater practices relying on infiltration of runoff are often inappropriate for the West Side.

Examples of Stormwater Practices

PSU Flow-Through Planters

Glencoe Elementary Rain Garden

Portland Building Ecoroof

Westmoreland Pavers

Green Street

Stormwater Stars Workshopsn Site Assessment

n Current challenges and constraints

n Desired site use

n Habitat type/opportunities

n Identify Risks

n Percolation test

n Designn Right plant, right place

n Creating opportunities to slow and store stormwater regardless of soil type

n Implementation!n Maintenance

Stormwater Stars PracticesStormwater Stars Workshops teach

practices that are suitable for nearly any site:

n TREES & other native plantsn Soil Restoration (Amendments)n Depavingn Porous Walkwaysn Ecoroofsn Container Plantings

Texas Green Street and wetland

A Word on Rain Barrels

✓Good for emergency water supply

⚠ Generally ineffective at managing stormwater due to small volume and long seasonal cycles of precipitation and drought

⚠ High cost for benefit

⚠ End of life cycle waste issue

Stormwater Practice Comparison

Maria Cahill, http://greengirlpdx.com/SWChallenge.htm

Workshop Project: SW Nevada St. n Site preparation: landowners

removed lawn and installed raised beds

n Improve soil pore space with Permamatrix & compost amendments, using broadfork

n Installed 38 native shrubs & pollinator plants

n Installed porous walkway

n Project area: 657 sq ft = 12,200 gallons of runoff reduced

Workshop Project: SW 5th Ave. n Site preparation: removed

invasive plant species, deteriorating plastic weed barrier

n Installed coir erosion control blanket

n Installed 234 native plants to promote slope stability

n Project area: 470 sq ft = 8,672 gallons of runoff reduced

Red Flags: Conditions Requiring Engineering/Permit

n Slope showing signs of movement (e.g. bend in tree trunk) n Projects above, near, or underneath a structuren Spring, seep or high groundwater tablen Facilities requiring plumbing or other connection to discharge

point (e.g. stormwater pipe) n Work within a creek (below ordinary high water mark) n Attempting stormwater infiltration or adding weight to the top

of a slopen Armoring creek bank with rock– may cause more erosion

downstreamn Moving > 10 cubic yards of soil or other material

Additional Resources

n Stormwater Stars registration and other resources at SW Watershed Resource Center:http://swni.org/stormwater

n Stormwater Stars Handouts (by Green Girl LLC)http://greengirlpdx.com/SWChallenge.htm

n ACF West Erosion Control materials:http://acfwest.com

n West Multnomah Soil & Water Conservation District: http://wmswcd.org