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Technical Equiv Rpt - Streamguard Catch Basin Inserts TECHNICAL EQUIVALENCY REPORT STREAMGUARD~ CATCH BASIN INSERTS FOR The project of 152nd Street East, 94th Avenue East and 160th Street East Public Road Improvements for `Kensington Estates' Pierce County, Washington April, 2000 Prepared for: Don Huber Pacific NW Home Construction, LLC P.O. Box 64160 Tacoma, WA 98464 Prepared by: Craig A. Deaver, Principal Project #98119.10 TABLE OF CONTENTS PAGE StreamGuard® Catch Basin Inserts ...............................................................................1 Attachment A Product Specifications Attachment B Product Comparison Attachment C Pierce County Section 7.7.4.2 Limitations Attachment D Pierce County Stormwater Treatment Information Attachment E Bio-swale Maintenance Program Attachment F Pierce Cotmty Section 7.7.4.2 Limitations StreamGuard® Catch Basin Inserts This report accompanies the storm drainage report, and the road, erosion control, and striping plans for the proposed 152nd Street East, 160 Street East and 94`~ Avenue East Public Road projects as submitted to Pierce County Planning and Land Services (PALS) and Pierce County Traffic Division. This report is being submitted for review and approval for technical equivalency for a StreamGuard® #3001 catch basin insert for water quality treatment in accordance with the Pierce County Surface Water Management Manual. It is proposed that all new catch basins as a part of the offsite road improvements for Kensington Estates shall be installed with StreamGuard® #3001 catch basin inserts for water quality treatment. The StreamGuard® filter can treat up to 1.lOcfs with a 93% removal of oil and grease. In addition to the removal of grease and oil, the filter will remove 80% of sediment. (See Attachment A for product specifications.) The proposed catch basin insert has a bypass for flows over 1. l Ocfs, however the flow rate for the developed 100-year 24-hour storm has been calculated to be 0.68cfs for the worst-case basin located at 160` Street East entire road basin. All other 100-year peak flows for the other road improvements areas have been calculated to be significantly less. As proposed, each roadway catch basin will be expected to handle flows up to .15 cfs. The catch basin inserts must be maintained every 6 months to assure maximum oil, grease and sediment removal (See Attachment A for maintenance information.). The 100-year, 24-hour storni type lA event was used in considering StreamGuard® catch basin inserts and their conveyance capacity. In order to show that the StreamGuard® model #3001 catch basin insert is technically equivalent to a Pierce County approved water quality device, the inserts were compared to approved water quality systems. A bioswale, which is accepted by Pierce County, will remove typically 60% to 70% of sediments (See Attachment B for Comparison Table). The catch basin inserts will remove 80% of sediment. The bioswale as a general rule will remove approximately 80% of oils. Based on the study provided the removal of grease and oils was 93% for the catch basin insert. It should be pointed out that the bioswale does not provide nutrient control as stated on page III-6-4 of the Department of Ecology Storm Water Management Manual "A biofiltration swale is designed to provide runoff treatment of conventional pollutants but not nutrients." The proposed insert also does not provide nutrient control. Underground wet vaults and tanks are an acceptable form of water quality treatment in Pierce County and do not provide nutrient control as shown on page 7-12 of the Pierce County Storrn Water Management Manual (See Attachment C for Limitations.). It is important to note that Pierce County already accepts a form of catch basin inserts for sediment removal (See Attachment D for Stormwater Treatment information.). It has been shown that the proposed StreamGuard® #3001 catch basin insert will meet or exceed the sediment and contaminant removal of approved water quality devices as approved in the Pierce County Storm Water Management Manual. 2 It is important to address and compare the maintenance of the proposed StreamGuard® #3001 catch basin insert with the other Pierce County approved storm water treatment devices. As previously stated, the catch basin insert should be maintained every 6 months as outline in Attachment `A'. However, the catch basin inserts should be inspected every month especially after high rainfall periods for sediment build up. Since the flow contributing to each catch basin is expected to be .15 cfs. or less, it is unlikely that the inserts will need to be removed and replace more than every 6 months. The approximated cost to maintain the proposed catch basin inserts on yearly basis is $2,000.00. In comparison, a biofiltration swale must be maintained regularly to maintain appropriate grass height and to remove sediment and debris. Mowing of the Swale must be completed twice a month during the months of April through October in order to maintain appropriate grass height. In addition, a bioswale must be removed of sediment and debris after storm events with rainfall of 1" or greater. (See Attachment `E' for Maintenance Program.) The annual maintenance cost of a biofiltration swale is expected to be approximately $1,000.00. Another approved treatment device, the underground wet tank, must be maintained on a monthly basis. As stated by the Pierce County Manual "Being underground, vaults and tanks are more difficult to inspect and maintain." (See Attachment F for Limitations.) Therefore, the annual cost to maintain vaults will far exceed the cost to maintain a bioswale or the proposed catch basin inserts. Finally, the catch basin inserts for sediment control, as approved by Pierce County, must also be 3 maintained on a regular basis and removed of sediment when the unit has accumulated approximately 12" of sediment. It is important to discuss the disposal of the catch basin insert debris and material. Sediment and minor oil drippings from automobiles is the expected to enter the catch basin insert. In telephone conversations with the manufacturer of the StreamGuard® catch basin insert it is recommended that the insert be disposed of in accordance with local jurisdictional requirements. Since the Pierce County Public Works Department does not have a method or recommendation for disposal of the catch basin inserts, the Tacoma-Pierce County Health Department was contacted (253-798-3512) to establish a method for disposal. The Tacoma- Pierce County Health Department requires that the sediment and heavy metals be disposed of at an approved location such as Fife Sand and Gravel (253-922-7710) or TPS Technologies (253-584-8430). After the debris is removed from the catch basin insert, the fabric that makes up the insert maybe disposed of at an approved landfill location. After providing anticipated oil saturation levels from the catch basin insert test data to the health department, it was determined that the inserts may be disposed of at an approved landfill as determined by the health department. Pierce County shall coordinate with the Tacoma-Pierce County Health Department in determining the appropriate landfill. In cases where obvious oil saturation levels exceed what is normally anticipated, the health department shall be contacted for a disposal location (253-798-3512) or Hazardous Waste Line (800) 287-6429. Some examples where oil levels may exceed the norm are direct dumping of oil from an automotive oil change into the 4 catch basin, an automobile accident where oil, gasoline or antifreeze is spilled into the catch basin. ' Normal use is expected to be daily pedestrian and vehicular traffic on the roadway. In conclusion, the StreamGuard® #3001 catch basin insert, in our opinion, has been shown to meet or exceed sediment and contaminate removal of approved Pierce County water quality devices. In addition, maintenance costs and intervals have also been shown to meet or exceed the cost and intervals of bioswales and wet tanks. It is important to reiterate that the contributing flows to each filter are expected to be minimal (.10). The StreamGuard® #3001 catch basin insert has been shown to be technically equivalent to other approved devices shown in the Pierce County Storm Water Management Manual. C.E.S. NW, INC. Craig A. Deaver Principal 5 ATTACHMENT A Rpr 18 00 02:22p Foss Environmen TM NONPOINT SOURCE POLLUTION CONTROL PRODUCTS The StteamG uard line of products incorporates innovative designs and new technologies to provide efficient, cost effective solutions. Exten- sively tested and engineered, each device is designed to remove pollutants From contaminated water. StreamGuard Oil & Grease Catch Basin Insert (#~ool 1113ox> (~~021 to-pack) NOW WITH NEW NON-LEACHING CO-POLYMER ABSORBENT! This oil-only model is equipped with an oil absorbent polymer. Unlike common adsorbents. the oleoQhilic StreamGtlardT'" polymer media will not deteriorate or release absorbed hydrocarbons. As contaminated water flows through the insert, the gcotextile fabric absorbs oil and retains sediment. Once contaminants have accumulated, the body of the unit fills with contaminated water and sediment is collected in the bottom of the insert. Floating oi[ and grease are absorbed by the StreamGuard Co-Polymer contained in a screen bag fixed within the unit. Great for parking lots and vehicle storage areas. FITS ANY SIZE CATCH BASIN UP TO 30" x 40"! 1/pack 2.61bs. NOTE: Reuse of the oil unit is not recommended due to the potential for release of captured oil that is absorbed in the insert fabric. If hartrrlotrs materials are be present in the stormwater, disposal of the inserts should be in accordance with local environmental regulations. INSTALLATION: 1) Remove catch basin grating 2) Clean dirt and debris from grating led;e. 3) Lay StreamGuard insert over the catch basin opening with the bag side of [he insert inside the basin. 4) Replace the ~atinb, pinchinb the insert fabric between the grating and the catch basin. 5) Cut the excess fabric off with a blade knife. A 3 to five inch wide strip of fabric should be left around the outside of the grating if insert is to be reused. MAINTENANCE: The StreamGuard"`' inserts for oil are designed to operate for up to 3 to 6 months under normal conditions. Where heavy oil and/or sediment contamination are present the unit will have a reduced life expectancy. The accumulation of sediment can be determined by probing with a yard stick. When the unit has collected about 6 inches of sediment it is recommended that it be replaced. The unit should also be replaced if free oil can be seen floating on the water in the bag. It is recommended that the inserts be regularly inspected and observations logged as a best mana;ement practice. Log sheet is included with each unit. Adaptor skirt (for a pcrfcd Retrieval strap fit) ~" 36" <. ~>,• ~ e ~~ Underflow ~,: ~: ~ Overflow discharge ~ (to bypass Geotextilc peak storm 24" fabric -'-' ~ volumes) _a ..- Oil absorbent ~--~ Sediment accumulation co-polymer PRUDUC.T SPECINICATIUNS [888)234-3677 p•1 Line An O 19Jr Foss 5nrionmawW. All Rigbls Reserved. Fabric Property Test Metbod Unit value Fabric Wei;ht ASTM D-5261 ozlydr 8.0 Thickness ASTM D-5199 mils 145 Water Flow Rate ASTM D-4491 gpm/ft'- 120* Total Surface Area by measurement square feet 18 Permeability ASTM D-4491 cm/sec .5 U.V. Resistance ASTM D-4355 % 70 • The total water flow rate Ihroush the insert in new condition is in excess of500 eom. The overflow rate is approximately 250 gym. rr,e $lreamCnrrd msd: Ana b an: o or ~ a I~+r Foe Emnonnranut Services. All righrt nserved. Rpr 18 00 02:22p Foss Environmen (8881234-367? P•2 RUBBERIZFR® is the polymer absorbent referred to in this report as "StreamGuardTM" and used in StreamGuard catch basin Inserts, Passive Skimmers, and Detectors. StreamGuardTM is a registered trademark of Foss Environmental Services. StreamGuardTM Polymer Leach Test per King County !_each Test Protocol OIL LEACHATE TEST FOR StreamGuardTM CO-POLYMER ABSORBENT MEDIA Performed by: Foss Environmental Services Introduction Various absorption and a~sorptian media are available on the market today for the contact removal of hydrocarbons from storm water. Many of these materials can subsequently degrade and release hydrocarbons after capture because they do not provide permanent encapsulation. Foss Enviranmental Services has introduced a true hydrocarbon absorbent which will not deteriorate with long-term exposure to oil- contaminated water and will not release captured oil. The absorbent polymer is used in the StreamGuard"" catch basin insert and Passive Skimmer for removing oil from storm water. To demonstrate this products' hydrocarbon non-releasing ability, leach tests were performed using a test method developed by King County Surface Water Management Division of Seattle, Washington (see attached test method}. Leach Test Method The method basically consists of saturating the media in a hydrocarbon mixture of 50% diesel and 50% used motor oil for approximately 20 hours. Then clean water is passed through the media at about.'/2gallon-per-minute (gpm} flow rate with five discrete samples for oil & grease collected at two-minute intervals. A media will pass this test if the leachate water samples contain less than 1D mg/L oil & grease. The'/z gpm water flow used to produce the leachate samples was generated with a small submersible pump in a 5-gallon water reservoir. The flow was moderated with a PVC ball valve attached to the discharge tubing of the pump and the flow was calibrated by observing the time required to fill a'/rgallon volume. Results The leach test was performed on a sample of the StreamGuardTM' particulate co- polymer. The results of the testing are recorded in the following table. ATTACHMENT B Apr 18 00 02:22p Fass Environmen (888]234-3677 p•3 FOSS ENYIRONIRfNTAI STREAMGUARDTM CATCH $ASIN INSERT PERFORMANCE DATA As Reported by Port of Seattle -Health, Safety, & Environmental Services Seattle, Washiington March 1998 In an effort to reduce the amount of oil, grease, and sediment in storm water runoff, the Port of Seattle installed Foss' StreamGuard Oil & Grease Catch Basin Inserts in several storm drains located in the passenger pickup azea at Seattlerl'acoma International Airport. An average of 50 Taxis per day park on the two acre paved area that drains into the catch basins monitored. Since early 1996 the Port has been sampling the treated water at a point downstream of the catch basins. Use of the StreamGuazd lnserts resulted in a 93% reduction of oil and grease and an 80% reduction in total suspended solids (TSS) in stormwater runoff. StreamGuard Insert Performance Data 140 2 1 0 - t~ ~ ~ .. _ ,. a~ E ~ 4 0 20 D Before StreamGuard Treatment Contaminant Level ®Oil & Grease ^Total Sediment ~~~5tomi=:t)ate` ~, -~ ~L~ast ;~A~ain"tenanttE~~' s~F ~~1~&f~ea ~T.4~a"~etiimetit, - ~A+CoEnmerit~-a-. ."~::;:; : . ~:'+S'+'^3r_.•:: ,':c.r.sc ...~. k:y - ~°' _ _ ~~ aced~:,~r '_ v'gR.~ it ~ .nc'_ '-'•a'~" . ,a"'t .< ~ _ :ku~.?n~' ~~; :=;~=; IUf :~ . ~~.'~rs it r :n. T, ~)~_=:: s:, :_~ . .4; a ....: ;_ .,~•=.:,:_''~-:, .;p;,:.,::,_-.,,r ' :,:: .: ... .. ._ ..... _, : ar.: n_;, u.:...y +:+: -- : _ ,. T=5:'; is :°:p _~•: 03/22/96 3!11!96 11 3.9 3 new bags installed 04/16/96 3111/96 36 3.7 30 3 new bags installed 04/22/96 4/18/96 4 2 23 2 new bags installed 07/03/96 4118/96 76 1.4 28 2 new bags installed 07!17/96 4/18/96 90 1.9 13 2 new bags installed 08!02!96 4118/96 106 1.6 33 2 new bags installed 10!04/96 9/3!96 31 1.4 17 4 new bags installed 02111!97 12/18/96 55 5.1 29 4 new bags installed 03!05/97 2!15!97 18 18* 188* 4 new bags installed Mean 51.1 Z.6 24.7 sd 37.1 1.4 7.4 CV, % 73°!0 54% 30% * excluded because of potential laboratory error FOSS ENVIRONMENTAd. (800)909-3677 fax: (888)2343677 a-atal: tossenv®fosse~-v.com PO Box 80327 Seattle, WA 98108 www.fosscatalog.com Rpr 18 00 02:23p Foss Environmen (8881234-3677 P•4 The following leach testing was performed in strict accordance with King County Oil Leach Test Methodology, April 1995. The tests were conducted by John Macpherson of Foss Envirotmental Services and supervised by Amy Grey -laboratory managec for Columbia Analytical Services {206) 486-6691 of Bothell, Washington. Parameter StreamGuardTM Polymer Date of Test 10/24/97 Weight of media 421 gms Volume of media 1 liter Volume of oil used 300 mL Volume of oil retained in media 244 mL Oil/media ratio 1.10 mL/gm Observation while adding the oil Oil flowed tluouglr media at a moderate rate but absorbed rapidly. Oil dripped into receiver in 68 mixture seconds. Sample 1 FES-A1 Water flow rate O.S gpm tttru the media. No reduction No oil sheen observed on leachate sample. of flow due to reduced media transmissivity observed Leachate clear and colorless. tluoughout the entire test with both media types. Both Leachate oil = <1.0 mg/1 media could }rave supported higher flow rates Sample 2 Fl?s-Az Water flow rate 0,5 gpm thru the media. No reduction No oil sheen observed on leachate sample. of flow due to reduced media ttanstnissivity observed Leachate clear and colorless. tltroughaut the entire test with both media types. Botit Leachate oil = <1.0 tng/1 media could have supported higher flow rates Sample ~ FES-A3 Water flow rate 0.5 gpm thru the media. No reduction No oil sheen observed on leachate sample. Leachate clear and colorless. of flow due fo reduced media trutsmissivity observed tlvougltout the ontire test with both media types. Bot}t Leachate oil =1.0 mE/1 media could have supported higher flow rates Sample 4 FE5-Aa No oil sheen observed on leachate sample. Water flow rate 0. S gpm tltru the media. No reduction Leacltate clear and colorless. of flow due to reduced media transmissivity observed titrougltout the entire test with both media types. Butlt Leachate oil = 1.2 mg/L media could have supported higher flow rates Sample 5 FES-AS Water flow rate 0.5 bpm thru the media. No reduction No oil sheen observed on leachate sample. Leacltate clear and colorless. of flow due to reduced media transmissivity observed throughout the entire test with both media types. Both Lrtchate uii = <t.0 mgll media could have supported higher flow rates All aspects of the leach test methodology were performed by Jolut Macpherson (professional analytical cltetnisi) for Foss Environmental Services of Seattle, Washington. 1 hereby attest that the test procedures performed by me were done so in strict accordance with the attached King County Oil Leach Test method. Oil & Grease Insert MSDS Yage 1 of 2 ~~ss Material Safety Data Sheet Product NameIFOSS ID#: StreamGuard Catch Basin Insert for Oil & Grease #3001 Product Description: Polypropylene I. Manufacturer Identification Manufacturer's Name: Foss Environmental Address: 200 SW Michigan Street Seattle, WA 98106 Emergency Telephone: (800) 909-3677 Telephone Number For Information: (800) 909-3677 II. Hazardous Ingredients/identity Information Hazardous Components(Specific Chemical Identity: Common Name(s)): N/A -There are no chemicals present in this product at a concentration of 0.1 % or greater c/ass~ed as a carcinogen by IARC, NTP, or OSHA. This product is not considered a hazardous substance by the EPA. OSHA PEL: ACG1H TLV: Other Limits Recommended: VI. Health Hazard Data Route(s) of Entry: Inhalation? Primary Skin? NIA Ingestion? Possible Health Hazards (Acute and Chronic) :None that are known Carcinogenicity: No NTP? No IARC? No OSHA? No Signs and Symptoms of Exposure: Respiratory conditions and eye irritation are possible and skin irritation as with exposure to any fine or grainy material. Medical Conditions Generally Aggravated by Exposure: respiratory conditions and eye irritation are possible and skin irritation as with exposure to any fine or grainy material. Emergency and First Aid Procedures: Flush affected areas thoroughly with water and consult a physician if irritation persists. III. Physical/Chemical Characteristics Boiling Point: NIA Vapor Pressure (mm Hg.) : N/A Vapor Density (Air = 1) :NIA Solubility in Water: Insoluble Specific Gravity (H2 0 = 1) :.89 - 1.1 Melting Point: N/A Evaporation Rate (Butyl Acetate) : N/A Appearance and Odor. Dark fabric/white grainy material; mild, sweet odor IV. Fire and Explosion Hazard Data Flash Point (Method Used) : ASTM D 92 3250 F Cleveland open cup Flammable Limits: Not yet established LEL: no data UEL: no data Extinguishing Media: C02 ,Water, foam, VII. Precautions For Safe Handling and Use Steps To Be Taken In Case Material Is Released Or Spilled: If material has not been contaminated it may be disposed of as a solid waste. If material is contaminated, dispose of accordingly. Waste Disposal Method: Product should be stored away from excessive heat and/or ignition source, preferable long term storage should be below 1250 F Precautions To Be Taken In Handling and Storing: Other Precautions: None VIII. Control Measures Respiratory Protection (Specific Type) None http://www.fossenv.com/MSDS's/Oil%20&%20Grease%20Insert.htm 04/18/2000 Oil & Grease Insert MSDS and dry chemical Special Fire Fighting Procedures: Protect against inhalation of combustion products. Unusual Fire and Explosion Hazards: None known. V. Reactivity Data Stability: Unstable: Stable: XX Conditions to Avoid: Ignition sources, excessive heat. Do not allow contact with strong oxidizing agents. Incompatibility (Materials to Avoid) :Strong oxidizing agents (i.e., concentrated nitric acid) Hazardous Decomposition of Byproducts: Combustion byproducts -hydrocarbons, aldehydes, carboxylic acid, carbon monoxide Hazardous Polymerization: Occur: III Not Occur: X Conditions To Avoid: Strong Oxidizing agents (i.e., concentrated nitric acid) Special: None vy. "..._~..,. vV.~.v~v~" Mechanical (General) :None Other: None Protective Gloves: Optional Eye Protection: None Other Protective Clothing or Equipment: None Work/Hygienic Practices: None Page 2 of 2 http://www.fossenv.com/MSDS's/Oil%20&%20Grease%20Insert.htm 04/18/2000 Oil & Grease Insert MSDS f D~~ Material Safety Data Sheet Product Name/FOBS ID#: Oil Absorbent, Non-Leaching Foss Polymer/#3001, 3017, 3024 Product Description: For catch basin inserts, skimmer, booms, and pillows I. Manufacturer Identification Manufacturer's Name: Haz-Mat Response Technologies, Inc. Address: 5841 Box Canyon Road La Jolla, CA 92037 Emergency Telephone: (800) 542-3036 Telephone Number For Information: (800) 542-3036 11. Hazardous Ingredients/Identity Information Hazardous Components(Specific Chemical Identity: Common Name(s)): N/A -There are no chemicals present in this product at a concentration of 0.1 % or greater classified as a carcinogen by IARC, NTP, or OSHA. This product is not considered a hazardous substance by the EPA. OSHA PEL: ACGIH TLV: Other Limits Recommended: III. Physical/Chemical Characteristics Boiling Point: N/A Vapor Pressure (mm Hg.) : N/A Vapor Density (Air = 1) : NlA Solubility in Water: Insoluble Specific Gravity (H2 0 = 1) :apparent - 0.40; real - 0.89 Melting Point: N/A Evaporation Rate (Butyl Acetate) : N/A Appearance and Odor. White grainy material; mild, sweet odor IV. Fire and Explosion Hazard Data Flash Point (Method Used) : ASTM D 92 3250 F Cleveland open cup Flammable Limits: Not yet established VI. Health Hazard Data Route(s) of Entry: Inhalation? Primary Skin? N/A Ingestion? Possible Health Hazards (Acr~te and Chronic) :None that are known Carcinogenicity: No NTP? No IARC? No OSHA? No Signs and Symptoms of Exposure: Respiratory conditions and eye irritation are possible and skin irritation as with exposure to any fine or grainy material. Medical Conditions Generally Aggravated by Exposure: respiratory conditions and eye irritation are possible and skin irritation as with exposure to any fine or grainy material. Emergency and First Aid Procedures: Flush affected areas thoroughly with water and consult a physician if irritation persists. VII. Precautions For Safe Handling and Use Steps To Be Taken In Case Material Is Released Or Spilled: If material has not been contaminated it may be swept up and returned to its container. If material is contaminated, dispose of accordingly. Waste Disposal Method: Incinerate or landfill according to government waste disposal regulations (local, state, and federal). Precautions To Be Taken In Handling and Storing: Product should be stored away from excessive heat and/or ignition source, preferable long term storage should be below 1250 F Other Precautions: None VIII. Control Measures Page 1 of 2 http://www.fossenv.corn/MSDS's/Oil%20&%20Grease%20Insert.htm 04/18/2000 Oil & Grease Insert MSDS ~c~: no oata u~~: no aata Extinguishing Media: C02 ,Water, foam, and dry chemical Special Fire Fighting Procedures: Protect against inhalation of combustion products. Unusual Fire and Explosion Hazards: None known V. Reactivity Data Stability: Unstable: Stable: XX Conditions to Avoid: ignition sources, excessive heat. Do not allow contact with strong oxidizing agents. Incompatibility (Materials to Avoid) :Strong oxidizing agents (i.e., concentrated nitric acid) Hazardous Decomposition of Byproducts: Thermal decombustioNcombustion may release hydrocarbons, aldehydes, keytones, alcohols, carboxylic acid, carbon monoxide and unidentified organic compounds. Hazardous Polymerization: Occur. Will Not Occur: X Conditions To Avoid: Strong Oxidizing agents (i.e., concentrated nitric acid) Respiratory Protection (Speck Type) Dust masks for airborne particles. Ventilation: Local Exhaust: Sufficient Special: None Mechanical (General) :None Other: None Protective Gloves: Optional Eye Protection: Goggles for dust protection Other Protective Clothing or Equipment: None Woric/Hygienic Practices: Working procedures should minimize airborne particles Foss Environmernal PO Box 80327 Seattle, Washington 98108 USA tel 800.909.3677 fax 888.234.3677 a-mail fossen~ossenv.com Page 2 of 2 http://www.fossenv.corn/MSDS's/Oil%20&%20Grease%20Insert.htm 04/18/2000 ATTACHMENT C PIERCE COUNTY STORMWATER MANAGEMENT and SITE DEVELOPMENT MANUAL 7.7.4.1 Location and Bypass If a wet vautt/tank is designed to provide runoff treatment but not runoff quantity control it must be located "off-line" from the primary conveyance/detention system. Flaws above the peak flow for the water quality design storm must bypass the facility in a separate conveyance to the point of discharge. A mechanism must be provided at the bypass point to take the facility "off-fine" for maintenance purposes. 7.7.4,2 Limitations Wet vaults/tanks cannot provide the equivalent level of treatment accomplished by wet ponds and constructed wetlands because neither biological uptake nor vegetative filtration are available as pollutant removal mechanisms. Gravity-settling of suspended so i s is a pnmary removal mechanism but vaults/tanks are unlikely to be as effective as open ponds in removing particulates because tittle or no soil layer exists in which to permanently stabilize trapped sediments. Also, being underground, vaults and tanks are more difficult to inspect and maintain. Therefore, they shall only be permitted for use on sites, with one acre of contributing area or less,,and then only after it has been demonstrated to the satisfaction of the County that more desirable BMPs are not practicable. 7.7.4.3 Design Considerations Wet vaults/tanks shall be a minimum of 20 feet from any structure, property line, and from any septic tank/drain field. All wet vaults/tanks shall be a minimum of 50 feet from the top of any steep slope. A geotechnical report must address the potential impact on a steep slope if it is proposed to be closer. The design criteria for a wet vau~/tank shall be the same as for Wet Ponds (conventional pollutants) and as detailed in Section 6.6.17. The length-to-width ratio at the design surface area shall be no less than 3:1. Where the wet vault/tank is designed to provide sediment containment, a minimum of 0.5 feet of dead storage depth shall be provided and the vault/tank shall be laid flat or the wet vault/tank shaft be divided into 2 cells using a baffle, with the first cell, the forebay, occupying about 25 per cent of the area. The top of the baffle wall must be coincident with the depth of the permanent pool. 7.8 PRESETTLING BASINS A presettling basin provides pretreatment of runoff in order to remove suspended solids which can impact other primary treatment BMPs. A presettling basin has no "permanent pool" volume; runoff is detained so that particulates can settle out before being discharged to another BMP. Runoff treated b}~presettling basin must be further treated by a water quality infiltration or ftltration BMP. such as a wet pond-type BMP or a biofilter prior to discharge to groundwater ~~ 7-12 ATTACHMENT E PIERCE COUNTY STORMWATER MANAGEMENT and SITE DEVELOPMENT MANUAL or right-of-way in a developed or disturbed area. Its purpose is to intercept sediment-laden water from disturbed areas, retain sediment, and release water in sheet flow. 8.11.4 Triangular Sediment Filter Dikes Refer to Appendix C, Detail 14.0 and Appendix G for standard notes regarding this practice. Triangular sediment filter dikes are temporary barriers constructed of wire mesh and geotextile fabric, installed along a flat area or across the toe of a slope. The purpose of a triangular sediment filter dike is to intercept and detain water-home sediment from unprotected areas of limited extent. They are to be used where there is no concentration of water in a channel or other drainageway above the barrier. If a concentrated flow does occur after installation, corrective action must be taken such as placing rock berms in the areas of concentrated flow. 8.11.5 Inlet Sediment Protection Refer to Appendix C, Detail 1.0, 2.0 and 3.0 and Appendix G for standard notes regarding this practice. Standard inlet protection techniques are intended for filtration of small amounts of sediment. The inlet protection shall be used in conjunction with other upstream erosion and sedimentation controls. They are not a replacement for upstream controls. The placement of a length of filter fabric cloth under a catch basin grate as the primary, sole, sediment control measure is not an acceptable practice. ~ Drop-in catch basin filters may be used in place of other standard inlet protection practices shown in Details 1.0, 2.0 and 3.0. In contrast to standard practices, this inlet protection technology can be used in situations where right-of--way flooding would be a problem. To maintain function, filters shall be removed and cleaned or replaced after each storm event. Contact the County to determine its acceptance of specific filter products. 8.11.6 Pipe Slope Drains Refer to Appendix C, Detail 15.0 and Appendix G for standard notes regarding this practice. The entrance shall consist of a standard flared end section for culverts greater than 12" diameter with a minimum six-inch metal toe plate to prevent runoff from undercutting the pipe inlet. The slope of the entrance shall be at least three percent. 8.11.7 Stair Stepping Cut Slopes And Grooving Slopes (Surface Roughening) Refer to Appendix G for standard notes regarding this practice. Graded areas with slopes greater than 3:1 but less than 2:1 shall be roughened before seeding. This can be accomplished in a variety of ways, including "trackwalking", or driving a crawler tractor up and dawn the slope, leaving a pattern of cleat imprints parallel to slope contours. Tread imprints trap seeds and encourage plants to become established. 8-14 ATTACHMENT D Y Frequenry Drainage Problem Conditions to Chedc For Conditions That Shou{d Exist System ~ Feature M Vegetation not and seedy or Grass cover is sparse Aerate soils and reseed and growing or . areas are overgrown with woody mulch bare areas. Maintain overgrown vegetation. grass height at a minimum of 6 inches for best stomrwater ant Remove woody growth, recontour, and reseed as necessary. M,S Erosion See Ponds Checklist See Ponds Cheddist damage to slopes M Conversion by .Swale has been filed in or blocked If possble, speak with homeowner to by shed, woodpile, shrubbery, eta homeowner and n:quest that incompatible swale area be restored. use ~ Contact the County to report problem if not rectified voluntarily. A Swale does not Water stands in Swale or flow A survey may be needed to drain velocity is very slow. Stagnation check grades. Grades need oaurs. to be in 1-5°~ range if possb(e. if grade is less than 1% underdrains may need to be installed. If you are unsure whether a problem exists, please contact a Professional Engineer. Comments: ~~ A=Annual (March or April preferred) M=Monthly (see schedule) S=After major stones (use 1-i^~ in 24 hours as a guideline) ~'^ J-31 ATTACHMENT "A" (CONTINUED) Maintenance Checklist for Conveyance Systems (Pipes, Ditches, and Swales) Frequenry Drainage Problem Conditions to Check For Conditions That Should Exist System ~ Feature M,S Pipes Sediment ~ Accumulated sediment that exceeds Pipe leaned of alt sediment debris 20% of the diameter of the pipe. and debris. M Vegetation Vegetation that reduces free All vegetation removed so movement of water through pipes. water flows freely through PiP~• p Damaged Protective coating is damaged; rust Pipe repaired or replaced. (rusted, bent, is causing more than 50% or avshed) deterioration to any part of pipe. M Any dent that significantly impedes Pipe repairnd or replaced. flow (i.e., decreases the cross section area of pipe by more than 20%). M Pipe has major cracks or tears Pipe repaired or replaced. allowing groundwater leakage. M S Open Trash i£ debris Dumping of yard wastes such as Remove trash and debris and , ditches grass clippings and branches into dispose as prescribed by the basin. Unsightly accumulation of County. nondegradable materials such as glass, plastic, metal, foam, and coated paper. M Sediment Accumulated sediment that exceeds Ditch cleaned of all sediment buildup 20% of the design depth. and debris so that it matches design. p Vegetation Vegetation (e.g., weedy shrubs or Water flows freely through saplings) that reduces free ditches. Grassy vegetation movements of water through should be left alone. ditches. M Erosion See Ponds Checklist. See Ponds Checklist. damage to slopes p Rock lining out Maintenance person can see native Replace rocks to design of place or soil beneath the rock lining. ' standard. missing (d applicable} Varies Catch See Catch Basins Checkl'~st See Catch Basins Checklist basins M,S Swales Trash ~ debris See above for Ditches. See above for Ditches. M ~ .Sediment See above for Ditches. Vegetation may need to be buildup replanted after leaning. -'~ J-30 ATTACHMENT F PIERCE COUNTY STORMWATER MANAGEMENT and SITE DEVELOPMENT MANUAL ~ 7.7.4.1 Location and Bypass If a wet vauit/tank is designed to provide runoff treatment but not runoff quantrty control it must be located "off-line" from the primary conveyance/detention system. Flows above the peak flow for the water quality design storm must bypass the facility in a separate conveyance to the point of discharge. A mechanism must be provided at the bypass point to take the facility "off-line" for maintenance purposes. 7.7.4.2 Limitations Wet vaults/tanks cannot provide the equivalent level of treatment accomplished by wet ponds and constructed wetlands because neither biological uptake nor vegetative filtration are available as pollutant removal mechanisms. Gravity-settling of suspended solids is the primary removal mechanism but vaults/tanks are unlikely to be as effective as open ponds in removing particulates because f'-ttle or no soil layer exists in which to permanently stabilize trapped sediments. Also. beino underground, vaults and tanks are more difficult to inspect and maintain. Therefore, they shall only be permitted for us'e on sites, with one acre of contributing area or less, and then only after it has been demonstrated to the satisfaction of the County that more desirable BMPs are not practicable. 7.7.4.3 Design Considerations Wet vaults/tanks shall be a minimum of 20 feet from any structure, property line, and ~~ from any septic tank/drain field. All wet vaults/tanks shall be a minimum of 50 feet from the top of any steep slope. A geotechnical report must address the potential impact on a steep slope if it is proposed to be closer. The design criteria for a wet vault/tank shall be the same as for Wet Ponds (conventional pollutants) and as detailed in Section 6.6.17. The length-to-width ratio at the design surface area shall be no less than 3:1. Where the wet vault/tank is designed to provide sediment containment, a minimum of 0.5 feet of dead storage depth shall be provided and the vault/tank shall be laid flat or the wet vault/tank shall be divided into 2 cells using a baffle, with the first cell, the forebay, occupying about 25 per cent of the area. The top of the baffle wall must be coincident with the depth of the permanent pool. 7.8 PRESETTLING BASINS A presettling basin provides pretreatment of runoff in order to remove suspended solids which can impact other primary treatment BMPs. A presettling basin has no "permanent pool" volume; runoff is detained so that particulates can settle out before being discharged to another BMP. Runoff treated by a presettling basin must be further treated by a water quality infiltration or filtration BMP such as a wet aond-tvoe BMP or a biofilter prior to discharge to groundwater. 7-12