Practical Protection & Restoration 9/27/11

The Science and Practice of Sustainable Sites: Why a Soil Standard? – Multiple Benefits Practical Implementation of Environmental/sustainability benefits • Protect/restore stormwater infiltration Soil Protection & Restoration • Bio-filtration of urban pollutants – protect waterways • Protect existing vegetation , improve tree & growth • Reusing organic “wastes” to restore soil function • Reduced irrigation use, less need for fertilizers & pesticides Value to builder/contractor • Quicker planting in prepped soil • Less plant loss = fewer callbacks David McDonald – Seattle Public Utilities • Better appearance sells next job Howard Stenn – Stenn Design Jim Berger – Port Blakely Communities Value to property owner • Better plant health & appearance 9/27/2011 seminar sponsored by the WA Chapter of the American Society of • Lower water bills Landscape Architects, UW Botanic Gardens, • Reduced chemical needs 1 2 and Seattle Public Utilities • Lower maintenance costs

Sustainable Sites Initiative WA State “Post Construction (SITES™) Rating System & Depth” BMP Summary of Soil Best Management Practices • Prereq. 1.1 Protect farmland in Dept. of Ecology Stormwater New Construction • Credit 1.5 Select brown/grey-fields Manual; coming into local codes  Retain and protect native topsoil & vegetation (esp. trees!) • Prereq. 2.1 Conduct pre-design • Soil management plan showing site assessment (incl. soil) areas to be protected, or • Choose sites to conserve good quality existing veg. & soil • Prereq. 2. 2 Use integrated site disturbed & restored, and • Minimize construction footprint development process soil//mulch import • Establish veg. & soil protection zones - fence & protect • Credit 4.4 Minimize soil amounts for each area disturbance (minimize grading) • Keep all impacts off protected • Store and reuse topsoil from site • Prereq. 4.3 Create a Soil veg. & soil areas • Retain “buffer” vegetation along waterways Management Plan • Prereq. 7.2 Restore soils • Restore disturbed areas by  Restore disturbed soils by tilling 2-4" of compost disturbed during construction amending with compost, into upper 8-12" of soil. Ripppy to loosen compacted layers. • Credit 7.3 Restore soils disturbed stock pili ng & reus ing topso il, or by previous development importing amended soil. Existing Landscapes • Prereq. 8.1 Plan for sustainable site Scarify subsoil, for 12” uncompacted depth. • Retrofit soils with tilled-in compost when re-landscaping maintenance • Mulch beds with organic mulches (leaves, wood chips, • Credit 8.3 Recycle organic matter • Mulch, and Maintain to replenish organic content. compost), topdress turf with compost, and mulch-mow to in operations & maintenance 3 4 www.sustainablesites.org www.buildingsoil.org maintain organic content that supports soil ecosystem.

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Understanding Soil: Sub-Soils in the Puget Sound Basin: development from parent “dirt” & rock Leftovers from glaciers & volcanoes glacial till: unsorted, unstratified mixtures of , silt, sand, Soil horizons & their evolution gravel, and boulders; deposited under ice, or in moraines hardpan: till compacted under glacier • Substratum (C) or bedrock (R) outwash soils: layers sorted by particle weathers physically & size by water - sand / gravel / rocks chemically to subsoil (B) lake/marine bed soils: clay or silt that settled out in lakes & estuaries • Primarilyygp biological processes create topsoil (A) volcanic ash: light, fertile, holds moisture - and organic (O) horizons mostly blown east of Cascades mudflows: mixed size, compact - like till Learn about Puget Sound soils at: USDA - NRCS 5 6 http://soils.usda.gov www.puyallup.wsu.edu/soilmgmt/Soils.htm

Glacial till Glacial outwash • May be piled, uncompressed • May be sorted boulders, gravel and unsorted, in moraines at • …sand and fines ….. edge or terminus of glacier •Or a mix!

• Basal till from under the glacier (1/2 mile of ice over Seattle!) has been compressed into hardpan

• Good for foundations, but low permeability and hard for roots to penetrate 7 8

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Volcanic ash Lake beds, or mudflows lenses, and layers • Tephra (ash) – light, fertile, holds moisture, erodable • Silts and clays settle out… • And then may be overlain in • Mudflow – compact, mixed fines and boulders, low lenses with sand or gravel from permeability, looks and acts like basal till, but more fertile succeeding outwash • Grey-yellow color when saturated and anaerobic • Great for farming, (best nutrient capacity) but unstable in slopes or foundations! 9 10

Layers upon layers… Alluvial soils ignore them at your peril!

• Sandy outwash over • Flat, loamy deposits compacted b asal till h ard pan in river floodplains (or ancient rivers) • Thin soil over bedrock • Clay lenses over hardpan, • Best for farming, or inter-layered with sand often wasted on (unstable!) development because they’re flat

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Disturbed soils in urban areas = mineral particle size (sand and finer particles) Ribbon + feel test: • TillTopsoil layer removed Mo isten soil , roll b etween • Compaction hands, then squeeze • Subsoil (or worse) fill out with thumb layers. • Debris or toxins? – Sand: no ribbon, grainy – Sandy : ½ inch ribbon – Loam: thick 1 inch ribbon – Silt: makes flakes rather than ribbon – Silty clay loam: thin, breaks easily, floury feel – Sandy clay loam: stronger, grainy

13 – Clay: long (3 inch) ribbon, smooth feel 14

Understanding soil: Understanding texture, structure, & pore space (thus infiltration) provides essential functions

Soil components: • “The Dirt” (mineral part) Good soil is about - half mineral –sand - half space (air & water) Soil – silt - plus a smaller but is –clay essential amount of alive! organic matter & soil life • Air and Water

“Loam” is a mix of • Organic Matter sand, silt, clay and organic, USDA-NRCS formed over time by nature and Soil Life “Soil Biology Primer” 15 16 (create aggregates & pores) S. Rose & E.T. Elliott http://soils.usda.gov/sqi/

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Common organisms in the soil foodweb Restoring soil life, to restore • Nematodes Soil organisms create: • Bacteria • • fertility = nutrient cycling • plant disease protection Soil Foodweb Inc. • Fungi Paul R. August, University of Minn. • Arthropods • biofiltration • erosion control Soil Foodw Soil • stormwater detention e

b Inc. SSSSSSA ••ProtozoaProtozoa ••EarthwormsEarthworms Compost kickstarts the soil ecosystem!

Wilhelm Foissner, 17 (Provides food and home for organisms)18 University of Salzburg

How does soil life create soil structure? How does soil life provide fertility (nutrient cycling)? • Bacteria secretions glue clays, silts and sands together into micro-aggregates. • Soil foodweb stores nutrients in living & dead organic matter • Micro-aggregatbdtes are bound • Nutrients are released in root zone as organisms eat and together by fungal hyphae, excrete “waste” (nitrogen, etc.) root hairs and roots. • Mycorrhizal fungi bring nutrients • Spaces are made by moving and water to roots of arthropods & , and decaying roots. • Only when all organisms are present can roots and water move into the soil with ease.

19 20 S. Rose & E.T. Elliott

Dr. Michael P. Amaranthus, Mycorrhizal Applications Inc.

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How does soil life provide plant disease protection? How does soil life filter out urban pollutants? Diversity  predation, parasitization & competition with the few disease-causing organisms • Creates structure • Bacteria cover leaf surfaces, block infection • Breaks down hydrocarbons, pesticides • Converts fertilizers to stable forms, so they are • Ecto- and endo- available to plants but mycorrhizae won’t wash away prevent root Soil Foodweb Inc. infection • Binds heavy metals iilhd’in soil, so they don’t • Many organisms wash into streams prey on the few disease-causing organisms 21 22

SSSA

How does soil life How does soil life provide stormwater control erosion? detention / infiltration? • Creates pore spaces, • Builds soil structure, increases infiltration moisture-holding capacity • Sticks soil particles & aggregates together • Increases surface with bacterial slime, fungal hyphae, porosity & root hairs (bigger aggregates are UW trials, turf on glacial till soil harder to move)  “aggregate stability” Compost- amended • Promotes rapid plant growth till soil – & deep root development up to 50% reduction in storm water runoff 23 24

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How can we enhance & restore , Site selection & planning to protect good soils to improve plant growth, water quality, and • Select previously disturbed sites instead of greenfields. reduce runoff? • Infill to enhance communities, connect with transit. • Protect existing soil & vegetation where possible • Start early to identify site values, and locate development on site to maximize protection of best soils , trees, habitat , • Prevent /reduce compaction natural drainage, etc. Involve arborists, soil & habitat (keep heavy machinery off) experts. Sell these values to developers/ decision makers. • Reduce intensive use of • Plan to minimize grading, soil export/import. pesticides & soluble fertilizers • Incorporate compost into soil to feed soil life

organic matter + soil organisms + time creates  soil structure, biofiltration, fertility, & stormwater detention25 26

Protecting soil & vegetation during construction Street tree protection • Fence vegetation & soil protection zones measures in action • Inform all contractors & subs: no stockpiling, trailers, etc. • If temporary vehicle access required, place steel plates over 6” coarse wood chi p.

401 Terry

Box trunks, protect root zones from compaction • Avoiding cutting roots – by using air & vactor, 27 or boring to place conduits. 28

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Sustainable Sites soil requirement: Manual for Implementing BMP T5.13 Prereq. 7.2 Restore soils disturbed during construction - also referenced by SITES 4.3 Soil Mgmt. Plan Ecology Stormwater Mgmt. Manual for Western WA: and 7.2 Restore Soils Disturbed by Construction BMP T5.13 Post-Construction Soil Quality and Depth • Retain & protect native soil and vegetation wherever possible • Manual developed regionally with experts • Areas cleared or graded required to restore min. soil depth: • Develop a “Soil Management Plan” for each site – Organic matter content (SITES  3%; Ecology  10% planting • Four options for soil management (can use 1 or more / site): beds, 5% for turf – driven by stormwater performance in NW) 1) Retain undisturbed native soil & vegetation, protect from compaction – SITES:  12-inch amended soil depth. Use native topsoil, amend 2) Amend existing soil in place with compost existing soil with compost, or import topsoil blend. 3) Stockpile topsoil prior to grading, and reuse on site (amend if needed) 4) Impor t topso il mee ting organi c matt er cont ent requi rement s – Ecology: Subsoil scarified 4 inches below 8-inch amended soil, for 12” finished uncompacted depth • Choose pre-approved or custom calculated amendment rates – Protect amended soil from compaction • Simple field inspection and verification procedures – Mulch after planting Available www.soilsforsalmon.org or www.buildingsoil.org – Maintenance practices to replenish organic content 29 30

How to Select Compost Know your supplier! Carbon to Nitrogen ratio of • Field tests: – earthy smell - not sour,,y, stinky, • For turf & most landscapes or ammonia • Mfr.-supplied info: C:N ratio of 20:1 to 25:1 - good nutrient availability for – brown to black color first year of growth (no other fertilizer needed) – Permitted WA composting facility – – uniform particle range meets WAC 173-350 requirements – stable temperature (does not – Meets US Compost Council (STA) • For native plants and trees get very hot if re-wetted) “Seal of Testing Assurance” C:N ratio of 30:1 to 35:1, and coarser (1” minus screen) – not ppyowdery or soakin g wet – CNC:N rat io – less Ni trogen b etter f or NW nati ves, di scourages weed s • Soil/compost lab test info: – Weed-seed trials – for streamside, unlikely to leach nitrogen –Nutrients – Nutrients, salinity, contaminants – Salinity – Size: “screen”, % fines –pH – % organic content (OM) 31 32

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Clearing up the confusion about “% organic” Compost Application Methods

“% Content” in lab soil tests Compost application & incorporation methods: is by loss-on-ignition method • Blowing - Most composts are 40-60% organic • Spreading content by this method ? • Tilling / ripping Recommended soil amendment rates • Blending off-site (for low-organic soils or sand-compost topsoil mixes):

• 5% Soil Organic Matter Content for Turf =15-25% compost amendment by volume

• 10% Soil Organic Matter Content for Landscape Beds =30-40% compost amendment by volume 33 34

Blowing & spreading Issaquah Highlands – the big scale • Blower trucks

• Various construction grading equipment

• Other equipment : golf course & farm spreaders

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Incorporating amendments into soil Stockpile site soils & amend, • Range of equipment after road & foundation work for different-sized sites • Till in to 8 ” depth • Allows mass grading • If compacted, • Can reduce hauling & disposal costs rip to 12” depth before/while amending • Set grade to allow re-application of topsoil & allow for settling • Amend stockpile to spec offsite, or after reapplication • Spread after concrete work • Rip in first lift, to reduce sub-grade compaction 37 38

Importing “Topsoil” Compost Based Erosion Control BMPs • “Topsoil” is not a defined, regulated product. Topsoil products often include subsoil, uncomposted organic • EPA-approved BMPs: materillial, land -clilearing and constructi idbion debris… blankets, berms, and socks • Best to use mixes containing only clean compost and see www.buildingsoil.org mined sand or “sandy loam” • “2 for 1” – use compost for erosion as defined by USDA. control, then till in at end to meet soil BMP: • Important to avoid clay that “2 for 1” – construction erosion can inhibit drainage – - No disposal costs control and soil quality BMPs are - Faster planting, better growth met with compost at Issaquah spec <5% passing #200 sieve Highlands. • Costs: blankets similar to rolled • See Seattle/WSU/PSP products, but savings on disposal, “Bioretention Soil” specification plus 2 for 1 benefits

at www.seattle.gov/util/GreenInfrastructure 39 40

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Combine methods as needed MULCHING: after planting, & annual maintenance for best water quality and flow control BENEFITS OF MULCHES: WsDOT - Protecting Wetland Area from I-5 Runoff • Limit weed growth, & make weeds that sprout easy to pull. • Conserve water , moderate soil temperature, and reduce erosion. • Replenish soil organic matter, enhancing soil biodiversity, Wetland structure, and nutrient cycling = increased plant vigor. WHAT: Arborist Wood Chip Mulch is best – see spec 9-14.4(5) www.seattle.gov/util/Engineering/Standard_Plans_&_Specs/index.asp - Bark can inhibit air & water, doesn’t build soil - Coarse compost builds soil but doesn’t suppress weeds. HOW MUCH: 2-4 inches wood chips, replenish annually 41 42 until plant canopy closes.

Developing A Soil Management Plan (SMP) 1: Review Landscape and Grading Plans Working with plans, check the soil in each area to assess how grading will • A scale-drawing identifying impact soil conditions and potential for reuse of topsoil excavated for building areas where each soil foundations, stormwater detention facilities and pavement. treatment option will be applied. • A completed SMP form identifying treatment options, amendment products and calculated application rates for each area. • Copies of laboratory analyses for compost and topsoil products to be used, with OM content and C:N 43

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Soil Treatment Options Amendment Rate Options 2. Identify Areas Suitable for Each Option Option 1. Retain undisturbed SITES™: native vegetation and soil, and Min. 3% OM = 1.5” compost into 12” soil protect from compaction during • Establish vegetation and soil protection zones where construction. WA DOE: “native” plants and duff– will be left undisturbed and OtiOption 2 . A mend exitiisting soil ilt at Pre-approved Amendment Rate protected from compaction during construction. pre-approved or custom calculated Turf: Mix 1.75 compost into 8” soil. • Excavated or graded topsoil suitable for stockpiling and rates based on soil and amendment Beds: Mix 3” compost in to 8” soil. reuse on site. tests. Pre-Approved Topsoil Import Rate • Compacted layers less than Option 3. Import topsoil mix of Place 8 inches of topsoil (or enough to provide 8 sufficient organic content and 12 inches deep (after grading) – inch depth with existing soil). depth. require scarification or soil import. Turf: 5% OM = 20-25% compost + 75-80% sand Option 4a. Stockpile native topsoil or loam. • Existing organic content in soil to during grading, and reapply after Beds: 10% OM = 35-40% compost + 60-65% be retained or stockpiled and construction. (import soil if needed sand or loam. reapplied – reduced amendment rate. to achieve depth). Option 4b. Amend stockpiled soil if Custom-Calculated Rate needed to meet 5-10% o.m. Test soil and amendment for organic content and density to determine amendment rate needed to 46 achieve organic content

3. Tests to Conduct for Custom Calculated 4. Select Amendment Options Amendment Rates Outline areas where each amendment option will be applied If planning to use calculated amendment rate, sample and test on plan. Assign each area a letter (A, B, C…) on the plan soil. Request compost test results from supplier. and Soil Management Plan form.

Soil Compost • Bulk density • Bulk density • Percent organic matter • Percent organic • Moisture content matter • Carbon to nitrogen ratio

Sampling and calculations must be performed by licensed Soil Scientist, Geologist, Civil Engineer or Landscape Architect.

47 48

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5. Calculate Amendment, Topsoil & Mulch Verification of PostPost--ConstructionConstruction Volumes on Soil Management Plan Form Soil Quality and Depth BMP • For Pre-Approved Amendment Rates: Calculate the sqqguare footage of modlSMPdel SMP ItiInspections each area, and complete calculations form is on page 13 in the for each area to convert inches of “Building Soil” manual, and on amendment into cubic yards. websites – a similar form is being developed for • To Compute Custom Calculated SITES™ Amendment Rates: Use soil and Verification amendment test results, and the Model Amendment calculators at: AdtRtClltAmendment Rate Calculator. www. buildingsoil. org • List products on the Soil Management www.soilsforsalmon.org Plan form. or (King County example) http://your.kingcounty.gov/solidwaste/ Dispute Resolution • Procure recent product test sheets compost_calculator.htm showing that compost or other organic or (Seattle soil amendment std. plan) materials specified meet requirements. http://www.seattle.gov/dpd/Codes/Sto49 rmwaterCode/Forms/

Who Will Verify BMP? Suggested Inspection Procedures

Primary • Pre-Grading Inspection • Code Enforcement Inspector • Grading Progress Inspection • May be assigned to Licensed Landscape • Post-Construction Inspection Architect • Mulch Verification

Independent Inspection to Resolve Disputes Exact number of inspections • Certifi ed S oil S ci enti st , C rop Ad vi sor or will vary between jurisdictions Agronomist and project type. • Licensed Landscape Architect, Civil Engineer or Example verification forms at Geologist www.soilsforsalmon.org

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Suggested Inspection Procedures Inspection / Verification Supplies

• Pre-Grading Inspection • Field Verification • Grading Progress Inspection Form • Post-Construction Inspection • Soil Management Plan • Mulch Verification • Site drawing

Exact number of inspections • Shovel will vary between jurisdictions • Tape measure and project type.

Example verification forms at www.soilsforsalmon.org

PrePre--GradingGrading / Grading Progress Post Construction Inspection (prior to planting) • Compare conditions to SMP / drawings • Verify nati ve soils & vegetation delineation and • Confirm volumes on amendment delivery tickets protection per SMP match approved SMP • Review SMP with general contractor and/or • Dig test holes to check depth of amended soil & grading equipment operator scarification • Verify erosion controls in place • Use shovel test to check uncompacted depth in • Verify excavation & stockpiling of native soils multiple locations consistent with SMP • Check sub-grades consistent with SMP

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Dig Test Holes to Check Depth of Check Soil Depth Amended Soil & Scarification

• At least three 12 inch deep •Use shlhovel or rod test holes (3 per acre “driven only by minimum ) for each inspectors weight” to treatment test for compaction • 8” depth of amended soil • Test 10 locations per (excluding mulch layer) ldlandscaped acre (10 • Scarified subsoil minimum per site).

Issaquah Highlands 1000 ft. elevation change, dense “urban village” development. Dispute Resolution 700 acres developed, 1400 acres deeded to King County as permanent open space. • Organics verified using Loss On Ignition method • No analytical method to verify scarification

Fildield Inspecti on and Verifi cati on guid e avail ilblable at www.soilsforsalmon.org (in Building Soil manual and as separate PDF)

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Spreading compost on prepared (track-walked) slope.

Slope preparation: track-walking with cat, tracks on contour (perpendicular to fall line) to promote infiltration and provide bonding for applied compost/topsoil.

The next spring. 100% plant cover on compost-amended slope.

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18”

Planting strips (between curb and sidewalk) re-excavated to 18” for placement of Blowing coarse compost on 2:1 slope. compost-amended soil before tree planting.

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Repairing erosion with blown-in compost blanket and seed.

Project Sequencing

 GMAGMA--vsvs--SoilSoil Conservation – GMA mandates higher density – Less opportunity for conservation on smaller lots and compact development – There may be no native soil & vegetation to conserve – Restoration more appropriate?

Compost blanket protects a steep slope as well as coir fabric over compost – expensive fabric not necessary.

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Soils Planning and Coordination

 Challenges – Is the soils plan practical? Dirt Cheap???Cheap??? Hauling dirt is expensive! Room to stockpile topsoil? RESULTS  Cost ––StockStockpileile--vsvs--exexpp/port/import: Stockpile & reuse is cheaper, if there’s room  Cost of compost – Save compared to hauling more topsoil

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Park establishment, using amended stockpiled topsoil.

Stormwater pond as amenity: compostcompost--amendedamended soil makes the difference.

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Hydroseed and straw mulch: the next spring – no growth.

Same slope, same seed, but applied with compost blanket: Compost and seed blown over rock road-cut face: next spring – slope’s stabilized, job’s done. superior erosion protection, and long-term plant success.

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Construction Sequencing for Soil Protection The green sells the project. Good soil makes the green. Design phase • Choose site & program to minimize impacts. • Identify vegetation & soil protection areas; verify they fit into development program and site access routes. • Identify areas to be graded, and soil restoration options. Calculate compost amendment, topsoil, & mulch on Soil Management Plan. Site grading through construction phases • Communicate Soil Management Plan to managers & contractors. • Fence vegetation & soil protection areas prior to first disturbance. • Stockpile topsoil to be reused with breathable cover. • Grade below finish grade to allow placing topsoil/amendments. • Compost based erosion BMPs can be reused as soil amendment. 86 • Place rock road bases ASAP and keep vehicle traffic on them.

Construction Sequencing for Soil Restoration (cont.) Learn More:  Protect existing soils and Post construction, pre-planting phase vegetation where possible. • Amend all disturbed soil areas or place amended topsoil.  Restore natural functions in • Avoid tilling through tree roots, or raising soil height on trunk. disturbed soils, • Plan for amended soil to settle, by placing amended soil higher, or by reducing compaction and retain/import amended topsoil to meet final grades. using organic amendments. www.SustainableSites.org After planting, end of project phase • Remove protection area barriers. Have arborist evaluate trees for stress/ need for remediation. • Mulch all planting beds (& tree root zones with exposed soil). • Protect amended/restored soils from compaction. • Communicate a landscape management plan to property owners. 87 www.BuildingSoil.org www.SoilsforSalmon.org88

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