Sediment Control Measures Treat the Problem! Storm Drain Inlet Protection Measures Water Body Protection Measures Down-Slope Protection Measures Stabilized Construction Vehicle Access & Exit Points Dust Generation & Track-Out from Vehicles Soil Stockpiles Non-Storm Water Discharges Sediment Basins
Storm Drain Inlet Protection Measures
Install appropriate protection measures to minimize the discharge of sediment prior to entry into the inlet Inlet Protection vs. Plow Destruction Habitat Protection? Where’s the Best in this management practice? This is No Place for Sediment to Collect - $$$$$$ What’s in this Storm System? Who’s Cleaning it Out? Protect Inlets Until Final Site Stabilization is Completed!
Bylaw 2006 No. 16138
Install and maintain filter fabric bags inside any catch basins, lawn basins, exposed manholes or any other storm sewer access point collecting runoff from the site. Inlet Protection Catch Basin Inserts Maintenance Issues Will Traffic Destroy Your Efforts?
Midtown Anchorage Will Your Efforts Destroy Traffic ?
Photo Courtesy David Jenkins Storm Drain Inlet Protection
• Keeps coarse sediment out of drainage systems • Above ground methods: silt fence, Exert, Dandy Bag • Below ground: catch basin filter
BMP WA C-220 OR SC-8 AK - 19 Water Body Protection Measures
Install appropriate protection measures to minimize the discharge of sediment prior to entry into the water body. For water bodies located on site or immediately downstream of the site. Tok Turbidity Curtain / Oil Boom • Where intrusion into a watercourse is necessary • Tidal and non-tidal uses • Maximum flow velocity of 5 feet per second • Locate parallel to flow, not across a channel
Kotzebue BMP OR RC-10 Columbia River Tidal Influences make maintenance difficult
Turbidity / Silt Curtain Ketchikan Down Slope Sediment Controls
Gakona Establish and use down-slope sediment controls where storm water will be discharged from disturbed areas of the site. Tok Install Sediment Controls
• Sediment Controls are BMPs Installed to Prevent Sediment from Leaving Your Site • Most Sediment Control Devices are Used to Pond/Collect Sediments (Not Filtration) • Without Application of Erosion Control BMPs Stormwater Runoff Cannot Be Properly Controlled Downslope • Erosion Control BMPs Prevent Soil Erosion at its Source – First Line of Defense Down-Slope Sediment Controls Choices Choices Choices
Silt Fence
Vegetated Buffer
Compost Berm Straw Wattle Perimeter Sediment Controls
Silt Fence and Geotextile Bales Compost Sock Sediment controls tight to the work area. Good, Bad, Both? Tasty BMP’s Installation Specs
Stake Size / spec
Sitka Trenched in? How Should We do Perimeter Control Here?
Glacier Highway Glacier Highway Perimeter Controls On the Cheap and Easy
Glacier Highway Gravel Berm Perimeter Control
Glacier HWY Juneau
Glacier HWY Juneau
Glacier HWY Juneau
Glacier HWY Juneau Temporary Crossings create unique challenges.
Glenn HWY @ Hicks Cr. Bridge Deck Perimeter Control
Ketchikan Break Up Ice Pass Thru & Scour ALL DISTURBED AREAS (EVEN SMALL AREAS) MUST HAVE SEDIMENT CONTROLS INSTALLED
Taylor Hwy SILT FENCE
. Must meet specifications . Sheet flow only . Trench into ground . Pull tight and place ends up slope . Wrap end stakes of adjoining sections . Reinforced and super silt fence
Courtesy DNREC Behold: The worlds most effective silt fence
Nome Silt Fence Installed on Contour BMP Silt Fence WA C-233
OR SC-1 AK - 18
• Used down slope of disturbed areas • Captures water and sediment • Contains site soils
• At grade pond Ft. Yukon Silt Fences Should Not Be Used for Concentrated Flows Silt Fences are Not For V-Shaped Channels Silt Fence Sedimentation
Evidence of Ponding
• Sedimentation Behind Silt Fences is Evidence of Proper Siltation • Without Sedimentation Water is Perhaps Flowing Underneath or is Going Someplace Else • When Sediment Accumulates up to 1/3 the Height of the Fence – Clean Out Wire Backed Silt Fence Sand Bag Toe & J Hooks
Ketchikan Sediment control measures must be constructed as one of the first steps in grading. These control measures must be functional before other land disturbing activities take place.
Muskeg Installation Petersburg Silt Fence Repair
Remove sediment from silt fences, check dams, berms or other controls before the accumulated sediment reaches one- half (½) the distance up the above-ground height (or it reaches a lower height based on manufacturer’s specifications) of the control measure. Fairbanks Frozen Ground Installation
Photo Courtesy Michael Travis Compaction of Backfill is Critical
• Good Compaction of Backfill is the Most Crucial Element of Proper Installment as it Prevents Saturation & Piping Underneath • Trenches Must Also Be First Cleaned of Debris to Help Avoid Blowouts Pocketed Silt Fence Silt Fence Fabrics Differ Greatly
BMP WA C-233 If you can see through it OR SC-1 AK 18 what can get through it? Longevity Break Up Survival Pity the BMP’s on the edge of the earth Receiving Water
BMP?
Barrow Compost Berm
Perimeter Control Slope length reduction Soil Amendments Down Slope Sediment Controls
Silt Fence
Straw Bale Barrier
Seeding Temporary BMP’s Must be removed Vegetated Strip
BMP WA C-234 Reduce the OR EP-2 AK - 16 transport of coarse sediment
Reduce the runoff velocities of overland flow Huslia
Frozen Arctic Perimeter Controls
Snow BermsKotzebue Stabilized Construction Vehicle Access & Exit Points
Rattle Racks
Establish construction vehicle access and
exit points and they must be stabilized. Anchorage Establish stabilized transitions to roadways & construction exits Site operators must provide an effective way of removing sediment from wheels to prevent trackout.
Anchorage If sediment escapes the construction site, off-site accumulations of sediment must be removed at a frequency sufficient to minimize off-site impacts. Uncontrolled Construction Access are Major Sources for Stormwater Pollution Keep the Rubber on the Rock!
*Hint Use Clean Rock USE CLEAN ANGULAR ROCK & MAINTAIN FOR EFFECTIVE PERFORMANCE OVER-EX FOR ROCK & PLACE SEPARATION FABRIC
Construction Road & Parking Area Stabilization BMP WA C-107 OR SC-10 AK - 21 Parking of Vehicles Willy - Nilly Does Not Help Mud Mats
Eagle SINGLE FAMILY RESIDENCE Individual Construction Entrance Provide a stabilized way to access the site. LARGER SITES WITH MORE TRAFFIC NEED LARGER & LONGER ENTRANCES
PERFORMANCE GOALS: No off site tracking to adjoining streets! Inspection / Corrective Action Modified Rumble Construction Entrance
Ingenuity in action Fairbanks Clean Up As You Go!
Public Roads Must Be Kept Clean Dirt Must Be Disposed of in Areas With Sediment Controls Staining vs. Tracking Rock Entrances Need to Be Maintained Good Housekeeping Everyone has a role to play Be Prepared to Clean up any tracking
Juneau Describe the corrective action Dust Generation & Track–Out from Vehicles
• Dust & Mud are Cousins • Dust Becomes Stormwater Pollution During Rain Events Plan Ahead for Dust Control! • Water Should Be Applied Prior to Construction Activity • Dust Suppressants Cannot Handle Heavy Equipment Traffic • Surfactants Can Increases Moisture Penetration
Minto DUST CONTROL
Employee & Public Health Concerns Water for dust control and compaction
Glenn HWY Equipment Operation for Dust Control • Keep Loader Close to Truck When Emptying • Mix Water & or Surfactants With Clay/Silt Soils • Avoid Construction Activity During High Winds
Barrow Drive Slowly & Cover Loads With Tarps Demolition Dust Control
• Apply Water to Demolition Debris • Make Sure that Water Does Not Become A Stormwater Pollutant Perimeter Wind Barriers
• In Areas Wind Barriers May Sometimes Be More Appropriate Than Silt Fences • Use Wind Barriers to Help Protect Bare Soils from Blowing Away Soil Stockpiles
Stabilize or cover soil stockpiles, protect with sediment trapping measures, and where possible, locate stockpiles away from drain inlets, water bodies, and conveyance channels. Sea-Tac Soil Stockpiles Keep Stockpiles From Impacting Stormwater
• Cover Stockpiles • Protect Stockpile Bases Taylor Hwy How Much Maintenance Do You Want to Do? Plastic Covering Source Control BMPs
• Immediate, short-term erosion protection to slopes and disturbed areas. • Cut and fill slopes and stockpiles. • Over newly-seeded areas • Install water collection measures at the base of the slope • Don’t mix clean runoff from plastic with dirty runoff
Other uses for plastic include: – Temporary ditch liner – Pond liner in temporary sediment pond; – Liner for bermed temporary BMP fuel storage area WA C123 – Emergency slope protection OR NS-9 during heavy rains
Photo Courtesy David Jenkins Plastic Cover Sandbags on 10’ Centers String “Net” Connections
WA BMP C-123 Non-Storm Water Discharges
Minimize any non-storm water discharge. Non-Stormwater Discharges Identify pollution prevention measures to ensure that pollutants are not introduced to these discharges and carried to nearby waterbodies.
•Water line flushing •Dust Control •Vehicle wash water without detergent
North Pole Sediment Basins
•Sizing depends on •Contributing drainage area •Precipitation •Topography •Soil Type
Wasilla Sediment Basins • Stormwater Runoff Shall Be Controlled
• Stormwater May Require Onsite Detention, Sediment Pond/Trap, Before Discharge Offsite “Rules of Thumb” • Site Area < 3 Acres – Sediment Trap
• Site Area > 3 Acres – Sediment Pond
• Controls Installed Before Construction Activity Begins – Last Line of Defense
Sediment Basin Limitations • Sediment Pond/Traps Cannot Filter Out Fine Sediments • Stormwater Discharges from Sediment Pond/Trap Can be Pumped Back Onsite for Increased Treatment • Remember that Sediment Ponds May be Designed for Post Construction Landscaped Areas – Not for Construction Activities Surface Outlets from Basins
•Use skimmer type outlets from basins, ponds, and impoundments Runoff from Disturbed Areas: Must pass through Key Points sediment pond or other sediment removal BMP before discharge
Runoff from Stabilized Areas: May be discharged off site without sediment control BMPs but must Design Criteria: adhere to Flow Volume ~ Acreage Controls Land Use ~ Precipitation Runoff Conveyance and Treatment BMPs
Sediment Trap • Small temporary ponding area with a gravel outlet • Used to collect and store sediment • Drainage area is less than 3 acres • Design life of approximately 6 months • Removes coarse sediments only! BMP WA C-240 OR SC-9 AK - 15 Juneau Runoff Conveyance and Treatment BMPs
Temporary Sediment Pond
• Contributing drainage area is 3 acres or more • Removes coarse sediments only
BM WA C-241 OR SC-9 Ketchikan Silt Fence
Sediment Bag
Baffles Outlet
Inlet
Ketchikan Dewatering Construction dewatering waters must be treated by an appropriate control measure. Appropriate control measures include*, sediment basins or traps, dewatering tanks, weir tanks, or filtration systems to remove sediment.
* Other Control Measures May Be Used Control Dewatering
• Plan the dewatering activity • Involve the approval agency • Monitor dewatering operations
Have a Plan! Control Dewatering
• Trench/Foundation Dewatering Shall Be Infiltrated, Conveyed, or Controlled Onsite by Proper BMPs • Clean Well Water Can Be Discharged into Surface Waters if it Does Not Cause Increased Flows or Erosion
Making Clean Water Dirty
Courtesy DNREC Dewatering Well Dispersal & Infiltration
Foundation Dewatering & High pH
Bylaw 6410-2006 Waters captured within a building foundation shall be pumped into the excavated sump or extracted by a pumper truck, not onto surrounding exposed areas. IS THIS WORKING? Bag 3 Bag 1 Bag 2
Hay Bale Dam
Soil Stabilization Minimum Requirements for Soil Stabilization Temporary Stabilization Final Stabilization Stabilize Soils
Stabilization efforts will affect water quality Parks Hwy Phasing
Stabilize all disturbed areas of the site to minimize on-site erosion Anchorage Erosion Control & Stabilization:
For any portion of the site where grade has been established and for areas where clearing, grading, excavating or other earth disturbing activities have temporarily ceased initiate stabilization. Anchorage Initiate Stabilization As soon as practicable or….
Within 14 days during dry conditions Immediately during wet season Land development guidelines Stabilize Soils With Hay/Straw
Hay/Straw Mulch Erosion Reduction
½ Ton 75% Per Acre 1 Ton 87% Per Acre 4.5 Tons 98% Per Acre Mulching
• Provide immediate temporary protection from erosion • Enhances plant establishment • On disturbed areas that require cover measures for less than 30 days.
Common mulches: – Straw – Wood chips – Compost – Bonded fiber matrix BMP WA C-12O OR EP-8 AK - 9 Vegetation & Erosion Prevention
Grass Seeding/Sod Erosion Reduction
40% Cover 90% 60% Cover 96%
90%+ 99% Cover Temporary & Permanent Seeding
• On disturbed areas that have reached final grade or that will remain unworked for more than 30 days. • Schedule stabilization around seeding windows. • Protect seed with mulch or plastic in cold weather. • Irrigate in dry weather until 75% cover established.
BMP WA C-120 OR EP-5 , EP-6 AK - 10 Standard Operating Procedure
Seeding was a normal operation conducted as needed throughout the active construction period. Tuntutuliak Tuntutuliak Tuntutuliak Why use native seed?
• It prevents the introduction of potentially unwanted pest species. • They are truly adapted to the area. • Their appearance is more pleasing. • It is a local business • Last but not least, it is required under Federal Rules Dormant Seeding
•Remains un-germinated until next growing season •Not immediately effective •Seed after first hard killing frost •Not on crusted or more than 4 inches of snow •Include annual and perennial species •Seed needs to be kept in place Have vegetation ready for Breakup & Spring Feeding Nome BMP WA C- OR EP-8 AK - 9 View from the bottom up View from the top down Source Control BMPs
Nets and Blankets • Prevent erosion & hold seed and mulch in place • Reinforce turf • Organic: biodegrade in place, 1-5 years BMP WA C-122 • Inorganic: long term high stress applications OR EP-10 AK - 14 Top soiling
• Provide a suitable growth medium for final site stabilization • What does your contract stipulate BMP WA C-125 you provide OR EP-4
Composting Stabilization
Improves Soil Structure Absorbs More Moisture Provides Soil Nutrients Suppresses Diseases Degrades Compounds/Pollutants Increases Surface Porosity Mimics Nature Facilitates Growth Extreme Topography Complicates Stabilizing Soils
and: Records of Disturbance & Stabilization -or- Grading Logs Steep Slope Blanket Installation
Safety First Treatment Chemicals
Requires: •Manufacturer MSDS Sheets •Trained employees •Site specific soil testing for treatability
Application of Treatment Chemicals The application of treatment chemicals shall be in combination with appropriate physical control measures (e.g., rolled erosion control products, ditch check dams, sediment basins, sediment bags, filtration, etc.) to ensure effectiveness and retention of the treatment chemical. Bylaw 2006 NO 4381
• Requires – Field testing kit for the Treatment Chemical, sensitive to one-tenth of the LC50. – If automated, a fail safe shutoff method. – Operations Manual & Qualified operators Additional Applications
Courtesy DNREC Flocculation • Chemicals flocculate suspended sediment by binding to several soil particles forming a larger aggregate or floc
Flocculation
• The large flocs then settle out of suspension or are filtered.
Bench Testing Chemicals & Dose Rates 1 Drop 2 Drops Control 1 Drop 2 Drops Control
1 2
1 Drop 2 Drops Control 1 Drop 2 Drops Control
3 4 1 Drop 2 Drops Simple pH Remediation System CO2 Injection pH Adjustment
Remediation Controller CO2 Injection
pH Sample Line Floating Suction for Shore-Side Pump
8-inch PVC pipe float 900 Elbow Suction hose
To pump Floating Suction for Shore-Side Pump
8” PVC floatation pipe Top View
Suction pipe To pump
2”x 4” braces
Suction pipe To pump Water level 8” PVC Floatation pipe Side View Submerged suction
Floating Barrel Surface Suction Dewatering Discharge 12” corrugated pipe w/ solid flocculant inside
Stabilized outlet
Rock baffle
Example of Passive Dosing CTS
Effect of Flocculant Pumping with no flocculant 12:03 Flocculant pump turned on
12:14
Clear water from bag 12:26 Petersburg, Alaska Runway Safety Area A Case study in Passive Treatment
Pop.2624 Haul Road Sediment Trap Treatment System
Dewatering Source
Dispersal System
Discharge Pipe
Wire Backed Perimeter Silt Fence
No Chitosan With Chitosan
Sediment Trap
Intake Weir Pond Perimeter