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Soils. Well-designed systems capture sediment near the entrances Sediment loads vary by facility Regular visual checks are the key. City of Portland Environmental Services. Soils. City of Portland Environmental Services. Soils . Visit the facility at least twice a winter after big storms
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Soils • Well-designed systems capture sediment near the entrances • Sediment loads vary by facility • Regular visual checks are the key City of Portland Environmental Services
Soils City of Portland Environmental Services
Soils Visit the facility at least twice a winter after big storms Check sediment accumulations as you’re doing routine maintenance Monitor draw-down rates – how long does it take for standing water to disappear after the end of a storm ? Make notes for future reference
When do You Need to Remove Sediment ? City of Portland Environmental Services If 2-3 inches of sediment accumulates When draw-down rates exceed about 36 hours Don’t let things get out of control (photo)
When do You Need to Remove Sediment ? City of Portland Environmental Services
Soils: Removing Sediment Schedule all maintenance for dry weather unless there’s an emergency Rakes and shovels (hand removal) are best to avoid damaging the plants Be sure to loosen the underlying native soil If large equipment is needed avoid compacting the soils If slow infiltration rates persist, remove the top couple of inches of soil
When to Be Concerned…. Morguefile • Petroleum sheen • Foul smell Nccwep.org
Soils: Sediment and Soil Disposal • Check for evidence of contamination: color and smell • In most cases stormwater sediment is not hazardous and can be disposed of as solid waste. • Places to be concerned: recycling facilities, fueling stations, industrial storage areas, etc. • If you have questions, contact DEQ at 503-229-5263. • Or consult DEQ’s guidelines for hazardous waste at http://www.deq.state.or.us/lq/hw/hwmanagement.htm
Mulch Green Girl Land Development Solutions Suppresses weeds and maintains soil moisture Is a surface for deposition of sediment (for easy sediment removal) Apply 2-3 inches after planting, after removing sediment, and any time there are bare spots Common mulches: medium hemlock,yard-debris compost. Gravel “mulch” is sometimes used at entrances
Mulch Green Girl LDS Mulch sometimes floats in the first storms just after construction. Yard debris compost is less prone to floating, but it can be a source of weeds Many LID systems are densely planted and need only spot-mulching after the first couple of years
Do’s and Don’ts Do • Visually monitor the facility on a regular basis • Remove sediment when it reaches 2-3 inches • Plan to take action if drawdown times exceed 36 hours • Mulch and plant bare spots for erosion control • Loosen the soil after removing sediment Don’t • Compact the soils by working in the facilities when the soils are wet (wait until summer) • Assume a facility is permanently clogged until steps have been taken to remove sediment layers • Handle soils that smell or look odd (contamination)
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