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HomeMy WebLinkAboutFPA2008-00011 FPA2001-00002 - FPA Plot / Site Plans - 1/18/2011MARTIN RD VI I\ ITY N,T,S, PURDY CUT-OFF RD, EAGLE POINT DR. vAP BRUCKDAL`L RD. cfN tiL T❑ SHELTON SHEET INDEX SHEET 1 OF 3 COVER SHEET AND PROPERTY LAYOUT SHEET 2 OF 3 CONTRUCTION AND EROSION CONTROL NOTES & DETAILS SHEET 3 OF 3 STORMWATER / EROSION CONTROL NOTES SCALE: 1 "= 100' FEET 0 100 200 /100 EROSION AND STORMWA TER CONTROL FOR FOREST PRACTICES ON PROPERTY OWNED BY CALIFORNIA ROAD LLC SECTION 27, TOWNSHIP 21 NORTH, RANGE 4 WEST, WM. PARCEL #421271300000 COVER SHEET AND PROPERTY LA YOUT APPOVFD FOR CONSTRUCTION BY: DATE: BY: DATE: APPROVAL EXPIRES DATE MARLEY L. YOUNG CONSULTING CIVIL ENGINEER P. O. BOX 1343 SHELTON, WASHINGTON 98584 (36D) 426— 7475 CO 0 I WN I- N Q I SHEET 1 OF 3 DRAWING NO. JOB NO. 2008-31 DRAWN BY: M.L.Y. CHECKED BY: M.L.Y. ENGINEERS CERTIFICATE 4� of wAsgj � I HEREBY CERTIFY THAT THE girENGINEERING SHOWN ON THIS 1 il DRAWING WAS PERFORMED BY ME OR UNDER MY DIRECTION. 11 `�EGrs 4 4 Dlb Ss7ONAL E��'l �(1, 2/1EY L. Y NG L.S.: l E. Sl y CONTACT : CALIFORNIA ROAD LLC 37614 39Tth Ave. South, Auburn WA 98001-8708 CONTACT: MANKE LUMBER CO. INC. MATT MANKE 826 FAIRMOUNT AVE. SHELTON, WA. 98584 TEL. 360 426 5536 Cell 360 490 9926 CALL BEFORE YOU DIG! CALL 2 WORKING DAYS BEFORE YOU DIG! 1-800-424-5555 UTILITIES UNDERGROUND \„ 46-1 LOCATION CENTER www.callbeforeyoudig.com 12" MIN. DEPTH 4" TO 8" QUARRY SPALLS PROVIDE FULL WIDTH OF INGRESS/EGRESS AREA STABILIZED CONSTRUCTION ENTRANCE N.T.S. 2' x 4' x 14 GA WELDED WIRE FABRIC OR EQUAL 2'x 2'x 5' DOUGL A S FIR STAKE AT 6'-6' MAX, O.C. (TYP,) CONSTRUCTION GEPTEXTILE FOR TEMPORARY SILT FENCE \ GENERAL NOTES: 1. ALL APPROVALS AND PERMITS REQUIRED BY THE COUNTY SHALL BE OBTAINED BY THE CONTRACTOR PRIOR TO THE START OF CONSTRUCTION. 2. THE CONTRACTOR SHALL BE FULLY RESPONSIBLE FOR THE LOCATION AND PROTECTION OF ALL EXISTING UTILITIES. THE CONTRACTOR SHALL VERIFY THE LOCATIONS PRIOR TO CONSTRUCTION BY CALLING THE UNDERGROUND LOCATE LINE AT 1-800-424-5555 A MINIMUM OF 48 HOURS PRIOR TO ANY EXCAVATION. 3. THE CONTRACTOR IS RESPONSIBLE FOR INSTALLING ANY BURIED UTILITIES AND ELECTRICAL LINES TO APPLICABLE CODES. 4. ALL WORKMANSHIP AND MATERIALS SHALL BE IN ACCORDANCE WITH MASON COUNTY STANDARDS AND THE MOST CURRENT COPY OF THE STATE OF WASHINGTON STANDARD SPECIFICATIONS FOR ROAD BRIDGE AND MUNICIPAL CONSTRUCTION (WSDOT/APWA. 5. ALL SURVEYING AND CONSTRUCTION STAKING SHALL BE PERFORMED BY AN ENGINEERING OR SURVEYING FIRM CAPABLE OF PERFORMING SUCH WORK. THE ENGINEER OR SURVEYOR DIRECTING SUCH WORK SHALL BE LICENSED BY THE STATE OF WASHINGTON. 6. WHEN PROJECT IS COMPLETE CONTRACTOR SHALL LEAVE THE SITE IN A NEAT AND PRESENTABLE CONDITION, CLEAR OF DIRT AND/OR DEBRIS. 7. THE CONTRACTOR SHALL BE RESPONSIBLE FOR PROVIDING ADEQUATE SAFEGUARDS, SAFETY DEVICES, PROTECTIVE EQUIPMENT, FLAGGERS, AND ANY OTHER NEEDED ACTIONS TO PROTECT THE LIFE, HEALTH, AND SAFETY OF THE PUBLIC AND TO PROTECT PROPERTY IN CONNECTION WITH THE PERFORMANCE OF WORK COVERED BY THE CONTRACTOR. ANY WORK WITHIN THE TRAVELED RIGHT-OF-WAY THAT MAY INTERRUPT NORMAL TRAFFIC FLOW SHALL REQUIRE AT LEAST ONE FLAGGER FOR EACH LANE OF TRAFFIC AFFECTED. ALL SECTIONS OF THE WSDOT STANDARD SPECIFICATIONS 1-07.23-TRAFFIC CONTROL SHALL APPLY. 8. THE CONTRACTOR SHALL NOTIFY THE PROJECT ENGINEER IN THE EVENT OR. DISCOVERY OF POOR DRAINING SOILS, STANDING GROUNDWATER, OR SEVERE DISCREPANCIES FROM SOIL INFORMATION AS ORIGINALLY REVIEWED. CONSTRUCTION NOTES : COMPACTION OF ALL FILL AREAS SHALL BE PER CURRENT WSDOT/APWA SPECIFICATIONS. FILL SHALL BE PROVIDED IN 8" MAXIMUM LIFTS AND SHALL BE COMPACTED TO 95 PERCENT OF ITS MAXIMUM RELATIVE DENSITY. CULVERTS: IF NECESSARY HANCOR HiQ - DOUBLE -WALLED, CORRUGATED, POLYETHYLENE PIPE, WITH A SMOOTH INTERNAL DIAMETER (AASHTO M-294 TYPE-S ADS N-12 PLASTIC PIPE 12"-24"0 ONLY) OR APPROVED EQUAL. COUPLED WITH A COMPANY -PRODUCED PVC COUPLING OR APPROVED EQUAL. 2' x 4' x 14 GA WELDED WIRE FABRIC OR EQU CONSTRUCTION PEP TEXTILE FOR TEMPORARY SILT FENCE S. S APO)! li1 ...�..'..y...�..4...� A •...♦...4......•.."..4...q..A. ., 'o'•'0 0 0 0 0 0 0 0 0 0 0 0 0 0 0. 0 0 0, 0 0,0' • 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 ' / sc,��/<</��/,��/ ���/p�/\C\;/QC( �/may/�y>y/�� C/�y\/ti /�/� \'(<("s \ ������ `�/iyi�/i` ELEVA TION 8'x 12' TRENCH 1 1/2' MINUS WASHED ROCK SILT LADEN _ 8'x 12" TRENCH FLOW NOTES: 2' EXCESS OVERLA TYPICAL CROSS-SECTION 1) SEE STANDARD SPECIFICATION 2-12,3(5), 2) STEEL POSTS MAY BE USED, SUPPORTED BETWEEN POSTS WITH WIRE FILTER FABRIC FENCE- IF NECESSARY N,T,S, EROSION AND STORMWA TER CONTROL FOR FOREST PRACTICES ON PROPERTY OWNED BY CALIFORNIA ROAD LLC SECTION 27, TOWNSHIP 21 NORTH, RANGE 4 WEST, WM. PARCEL #421271,300000 CONSTRUCTION AND EROSION CONTROL NOTES & DETAILS EROSION AND SEDIMENT CONTROL REQUIREMENT: THIS THINNING PROJECT WILL DISTURB APPROXIMATELY 46.0 ACRES_ PER THE DOE STORMWATER MANAGEMENT MANUAL - ALL NEW DEVELOPMENT THAT INCLUDES THE CREATION OR ADDITION OF 5,000 SQUARE FEET, OR GREATER, OF NEW IMPERVIOUS SURFACE AREA, AND /OR LAND DISTURBING ACTIVITY OF ONE ACRE OR GREATER, SHALL COMPLY WITH THE MINIMUM REQUIREMENTS #1 THROUGH #11. 1. WHERE APPLICABLE, THIS PROJECT SHALL COMPLY WITH LARGE PARCEL EROSION AND SEDIMENT CONTROL REQUIREMENTS 1 THRU 11 FOUND IN SECTION 1-2.5 OF THE WASHINGTON STATE DEPARTMENT OF ECOLOGY STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN (THE TECHNICAL MANUAL). 2. WHEN NECESSARY THE PRIVATE CONSTRUCTION VEHICLE ACCESS SHALL BE MAINTAINED TO COMPLY WITH EROSION AND SEDIMENT CONTROL REQUIREMENTS FOUND IN THE WASHINGTON STATE DEPARTMENT OF ECOLOGY 'MANUAL'. IF A POTENTIAL FOR TRACKING MUD AND DEBRIS OCCURS, THE CONTRACTOR SHALL IMMEDIATELY ELIMINATE THE POTENTIAL. 3. CONSTRUCTION VEHICLE ACCESS SHALL BE, WHENEVER POSSIBLE, LIMITED TO ONE ROUTE. ACCESS POINTS, WHEN NECESSARY, SHALL BE STABILIZED TO MINIMIZE THE TRACKING OF SEDIMENT ONTO PUBLIC HIGHWAYS, WHENEVER CONSTRUCTION VEHICLE ACCESS ROUTES INTERSECT PAVED STREETS, PROVISION MUST BE MADE TO MINIMIZE THE TRANSPORT OF SEDIMENT ONTO THE PAVED STREET. IF SEDIMENT IS TRANSPORTED ONTO A STREET, THE STREET SHALL BE CLEANED IMMEDIATELY, AND THOROUGHLY CLEANED AT THE END OF EACH DAY. 4. SEDIMENT TRAPS, SEDIMENT BARRIERS AND OTHER BMP'S INTENDED TO TRAP SEDIMENT ON SITE SHALL BE CONSTRUCTED AS NECESSARY. STANDARD STORMWATER NOTES: 1. A COPY OF THESE APPROVED STORMWATER PLANS MUST BE ON THE JOB SITE WHENEVER CONSTRUCTION IS IN PROGRESS, 2. THE STORM DRAINAGE SYSTEM SHALL BE CONSTRUCTED ACCORDING TO THESE APPROVED PLANS ON FILE WITH THE COUNTY. ANY SIGNIFICANT DEVIATION FROM THESE APPROVED PLANS WILL REQUIRE WRITTEN APPROVAL FROM THE COUNTY. 3. IN ANY AREA WHICH HAS BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND DISTURBING ACTIVITIES AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A PERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE IMMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING, OR OTHER APPROVED EROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR IN QUESTION. GRASS SEEDING ALONE WILL BE ACCEPTABLE ONLY DURING THE MONTHS OF APRIL. THROUGH SEPTEMBER, INCLUSIVE. SEEDING MAY PROCEED, HOWEVER, WHENEVER IT IS IN THE INTEREST OF THE DEVELOPER/CONTRACTOR, BUT MUST BE AUGMENTED WITH MULCHING, NETTING, OR OTHER TREATMENT, 4. ALL EROSION CONTROL AND STORMWATER FACILITIES SHALL BE REGULARLY INSPECTED AND MAINTAINED BY THE CONTRACTOR DURING THE CONSTRUCTION PHASE OF THE DEVELOPMENT PROJECT. THE FOLLOWING SHALL BE ADHERED TO ON ALL CONSTRUCTION SITES WITH EROSIVE SOILS AND/OR A GRADIENT OF GREATER THAN 2 PERCENT FOR LIMITING EXPOSED SOILS TO EROSIVE PROCESSES. MAY 1 TO SEPTEMBER 30 (DRY SEASON) THE CLEARING OF LAND, INCLUDING THE REMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO ONLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE OTHERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED, BY NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE STABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENTATION CONTROL PLAN, ALL AREAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED THROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED PLAN OF ACTION, UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, FERTILIZING, AND MULCHING OF CLEARED OR OTHERWISE DISTURBED ARE''S SHALL BE PERFORMED DURING THE FOLLOWING PERIODS: MARCH 1 TO MAY 15 AND AUGUST 15 TO OCTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION OF THE PROJECT IS IMMINE'+'T AND THE ENVIRONMENTAL CONDITIONS ARE CONDUCIVE TO SATISFACTORY GROWTH. IN THE EVENT THAT PERMANENT STABILIZATION IS NOT POSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER (SUCH AS MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, ETC.) MUST BE INSTALLED PY NO LATER THAN SEPTEMBER 30, IN THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT ACTIVITIES ARE DISCONTINUED FOR 4 CONSECUTIVE DAYS OR MORE, THE PROPONENT SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION AND SEDIMENTATION CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT LEAST ONCE EVERY WEEK. THE PROPERTY OWNER SHALL BE RESPONSIBLE FOR THE MAINTENANCE AND REPAIR OF ALL EROSION AND SEDIMENTATION CONTROL FACILITIES. OCTOBER 1 TO APRIL 30 (WET SEASON) ON SITES WHERE UNINTERRUPTED CONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE REMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, SHALL BE LIMITED TO ONLY AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN THE EVENT A MAJOR STORM IS PREDICTED AND/OR EROSION/ SEDIMENT TRANSPORT OFF -SITE IS OBSERVED. ADDITIONALLY, ALL CLEARED OR DISTURBED AREAS WILL RECEIVE APPROPRIATE PROTECTIVE COVER OR BE OTHERWISE STABILIZED (SUCH AS MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC.) WITHIN 5 DAYS AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED. FILTER FABRIC FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC., WILL NOT BE VIEWED AS ADEQUATE COVER IN AND OF THEMSELVES. IN THE EVENT THAT ANY LAND AREA NOT BEING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY STABILIZED 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON THE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENTATION CONTROL ACTIVITY, SHALL IMMEDIATELY CEASE UNTIL SUCH A TIME AS SAID LAND AREA HAS BEEN APPROPRIATELY PROTECTED OR STABILIZED. THE CONTRACTOR SHALL AT ALL TIMES HAVE AVAILABLE FOR THE PROJECT SUFFICIENT QUANTITIES OF PROTECTIVE COVERING MATERIALS TO IMMEDIATELY STABILIZE ALL DISTURBED AREAS IN CASE THE PROJECT ENGINEER OR COUNTY DIRECTS HIM/HER TO COVER DUE TO OBSERVED MIGRATION OF SOILS OR INCLEMENT WEATHER, (REFER TO EROSION CONTROL NOTES #5). 3:1 SL PE 3:1 SLOPE 1OO i 3:1 SLOPE 3:1 SLOPE LAYOUT OF FLAT BOTTOM DITCH TO BE PLACED PARALLEL TO THE POWER LINE EASEMENT 11.71 EROSION CONTROL NOTES: STABILIZED CONSTRUCTION ENTRANCE(s) 1. THIS SITE DOES NOT HAVE A STABILIZED ENTRANCE. A TEMPORARY CONSTRUCTION ENTRANCE AS PER THE D.O.E. MANUAL IS REQUIRED. THE STABILIZED CONSTRUCTION ENTRANCE DETAIL IS SHOWN ON THESE CIVIL DRAWINGS. THE SITE LOCATION TO BE DETERMINED BY THE CONTRACTOR. 2. SHOULD THE NATURAL EROSION AND SEDIMENTATON CONTROL MEASURES NOT PROVE ADEQUATE TO CONTROL EROSION AND SEDIMENTATION, THE DEVELOPER/CONTRACTOR SHALL INSTALL ADDITIONAL FACILITIES AS NECESSARY TO PROTECT ADJACENT PROPERTIES, SENSITIVE AREAS, AND/OR THE STORM DRAINAGE SYSTEM. 3. THE PROPOSED CLEARING LIMITS FOR THE PROPOSED THINNING SHALL BE DEFINED BY THE OWNER OR THEIR ASSIGNS. FLAGGING OR OTHER IDENTIFICATION MAY BE USED. THE BUFFER LIMITS SHALL ALSO BE CLEARLY MARKED WITH FLAGGING. 4. THE CONTRACTOR SHALL PROVIDE MATERIALS ON -SITE READILY AVAILABLE TO IMMEDIATELY STABILIZE DENUDED AREAS DURING PERIODS OF INCLEMENT WEATHER WHICH RESULT IN EROSION AND SEDIMENT TRANSPORT OFF -SITE. AS A MINIMUM THE CONTRACTOR SHALL HAVE ON HAND 30 STRAW HAY BALES AND FOUR (20 FT. BY 100 FT.) ROLLS OF 6 MIL PLASTIC COVERING. 5. ALL WORK ASSOCIATED WITH STABILIZING THE DISTURBED AREAS SHALL BE IN ACCORDANCE WITH THE MASON COUNTY STORMWATER MANAGEMENT MANUAL. 6. ALL NECESSARY FACILITIES SHALL BE MAINTAINED ON SITE TO PREVENT DEBRIS, DUST, AND MUD FROM ACCUMULATING ON PUBLIC OR PRIVATE PROPERTY OR RIGHT OF WAY. SILT FENCES or FILTER FABRIC FENCE - IF NECESSARY: 1. FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL AND CUT TO THE LENGTH OF THE BARRIER TO AVOID USE OF JOINTS. WHEN JOINTS ARE NECESSARY, FILTER CLOTH SHALL BE SPLICED TOGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP, AND SECURELY FASTENED AT BOTH ENDS TO POSTS. 2, POSTS SHALL BE SPACED A MAXIMUM OF 6 FEET APART AND DRIVEN SECURELY INTO THE GROUND (MINIMUM OF 30 INCHES). 3. A TRENCH SHALL BE EXCAVATED APPROXIMATELY 8 INCHES WIDE AND 12 INCHES DEEP ALONG THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER. THIS TRENCH SHALL BE BACKFILLED WITH WASHED GRAVEL. 4. WHEN STANDARD STRENGTH FILTER FABRIC IS USED, A WIRE MESH SUPPORT FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE OF THE POSTS USING HEAVY-DUTY WIRE STAPLES. AT LEAST 1-INCH LONG, TIE WIRES OR HOG RINGS. THE WIRE SHALL EXTEND INTO THE TRENCH A MINIMUM OF 4 INCHES AND SHALL NOT EXTEND MORE THAN 24 INCHES ABOVE THE ORIGINAL GROUND SURFACE. 5. THE STANDARD STRENGTH FILTER FABRIC SHALL BE STAPLED OR WIRED TO THE FENCE, AND 20 INCHES OF THE FABRIC SHALL BE EXTENDED INTO THE TRENCH. THE FABRIC SHALL NOT EXTEND MORE THAN 24 INCHES ABOVE THE ORIGINAL GROUND SURFACE. 6. WHEN EXTRA -STRENGTH FILTER FABRIC AND CLOSER POST SPACING IS USED, THE WIRE MESH SUPPORT FENCE MAY BE ELIMINATED. IN SUCH A CASE, THE FILTER FABRIC IS STAPLED OR WIRED DIRECTLY TO THE POSTS WITH ALL OTHER PROVISIONS OF ABOVE NOTES APPLYING. 7. FILTER FABRIC FENCES SHALL NOT BE REMOVED BEFORE THE UPSLOPE AREA HAS BEEN PERMANENTLY STABILIZED. 8. FILTER FABRIC FENCES SHALL BE INSPECTED IMMEDIATELY AFTER EACH RAINFALL AND AT LEAST DAILY DURING PROLONGED RAINFALL. ANY REQUIRED REPAIRS SHALL BE MADE IMMEDIATELY. 9. SILT FENCES WILL BE INSTALLED PARALLEL TO ANY SLOPE CONTOURS. 10. INSTALL DOWNSLOPE OF EXPOSED AREAS. 11. DO NOT DRIVE OVER OR FILL OVER SILT FENCES. SEEDING - FOR ALL RAW SLOPES: 1. SEED MIXTURE SHALL BE AS SHOWN BELOW, AND SHALL BE APPLIED AT THE RATE OF 120 POUNDS PER ACRE. 2. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO FOSTER AND PROTECT THE ROOT STRUCTURE. 3. FOR SEED BEDS PLANTED BETWEEN OCTOBER 31 AND APRIL 30, ARMORING OF THE GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING). 4. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL MEASURES SUCH AS DIKES, SWALES, LEVEL SPREADERS AND SEDIMENT BASINS. 5. THE SEEDBED SHALL BE FIRM WITH FAIRLY FINE SURFACE, FOLLOWING SURFACE ACROSS OR AT RIGHT ANGLES TO THE SLOPE. 6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS' RECOMMENDATIONS. AMOUNTS USED SHOULD BE MINIMIZED, ESPECIALLY ADJACENT TO WATER BODIES AND WETLANDS. USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION CONTROL, OR A COUNTY -APPROVED ALTERNATE SEED MIXTURE. Name Redtop (Agrostis alba) Annual rye (Lolium multiflorum) Chewing fescue (Festuca rubra commutata) (Jamestown, Banner, Shodow, or Koket) White dutch clover (Trifolium re pens) Proportions Percent by Weight Purity 10 40 40 percent percent percent 10 percent 92 98 97 Percent Germination 90 90 80 96 90 MULCHING - FOR ALL RAW SLOPES: 1. MULCH MATERIALS USED SHALL BE WOOD FIBER CELLULOSE, AND SHALL BE APPLIED AT THE RATE OF 1000 POUNDS PER ACRE 2. MULCH SHALL BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES GREATER THAN 2:1. 3. MULCHING SHALL BE USED IMMEDIATELY AFTER SEEDING OR IN AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASON. 4. ALL AREAS NEEDING MULCH SHALL BE COVERED BY NOVEMBER 1. 12' 3.1 VARIABLE FLAT BOTTOM ORIGINAL W GROUND '`�\.�GINAL ��b' , GRND e✓1�•`J`� :v -r •/ryN%/ v ✓r:ORIGINAL<� 3.1 - 6.0' POWER EASEMENT SEED BED WILL BE NECESSARY, (e.g., GRADIENT TERRACES, INTERCEPTOR ROUGHENING. PERFORM ALL OPERATIONS BERM FROM DITCH EXCAVATION CROSS SECTION OF FLAT BOTTOM DITCH TO BE PLACED PARALLEL TO THE POWER LINE EASEMENT N.T.S. LLI 0 LL APPROVED O co CO OD O Lv N I DRAWING NO. m c J• H APPROVAL EXPIRES z • co o 0 Th N LLI • • U � FOREST PRACTICES APPLICATION STORMWATER/EROSION CONTROL REVIEW I. PROJECT OVERVIEW CALIFORNIA ROAD LLC. OWNERS OF 46 ACRES - The Forest Practices Application is for the thinning of timber from their property located in Section 27, T. 21N., R. 4 W., W.NI., Parcel No. 42127 13 00000. Landowner wishes to conduct an uneven aged and salvage type harvest to ensure proper crown spacing and to reduce pockets of disease and defects. All necessary roads and landings are already on the site. Approximately 50 MBF to be harvested. Removal is to be completed using rubber tired skidder. This project is located in an area designated by Mason County as Rural, adjacent and west of the California Road. Topography within the property is relatively flat with no slopes exceeding 10 %. Generally there are no saturated conditions that would lead to sliding. The calculated additional post stormwater runoff caused by the thinning will infiltrate into the ground. Post storm runoff will be less than pre storm runoff. The soil survey of Mason County indicates that the onsite soil type, (USDA1951) is Grove gravelly sandy loam. The Grove Soil is classified as SCS Soils Group A. Group A has the fastest infiltration rate. Experience has shown that the infiltration rate for this soil is: 10 inches per hour. MINIMUM REQUIREMENTS The project shall comply with D.O.E's 1992 Stormwater Management Manual for the Puget Sound Basin, New Development Minimum Requirements #1 through #11. Minimum Requirement #1: EROSION AND SEDIMENT CONTROL Refer to EROSION and SEDIMENT CONTROL PLAN DURING THE TIMBER THINNING located on this sheet. Minimum Requirement #2: PRESERVATION OF NATURAL DRAINAGE SYSTEMS Natural drainage patterns shall be maintained, and discharges from the site shall occur at the natural location, to the maximum extent practicable. There are no identifiable drainage patterns. The property is virtually flat. To retain stormwater on site for infiltration, a ditch will be installed and located on the west side of the Bonneville Power Line. The floor of the ditch will be 12 feet wide with 3:1 slopes and be 2 feet in depth. A burn of excavated materiral will be located on the easterly side of the ditch. See Page 2 of 3 for Details. Minimum Requirement #3: SOURCE CONTROL OF POLLUTION * Source control BMPs shall be applied to all projects to the maximum extent practicable. Source control BMPs shall be selected, designed, and maintained according to an approved manual. The 46 acres is 1 drainage basin. The ditch will act as a settling pond, a treatment facility and also provide total infiltration for the stormwater from the property to the west. Stormwater from the property to the east will continue to flow unrestricted - 'free flow'. The sum of the runoffs will be less than the calculated pre project runoff. Minimum Requirement #4: RUNOFF TREATMENT BMPS * First priority for treatment shall be to infiltrate as much runoff as possible, if site conditions are appropriate and ground water quality will not be impaired. In addition to the treatment received from the flat bottomed ditch, the runoff treatment will also be primarily the natural treatment received by overland flow and infiltration. Minimum Requirement #5: STREAMBANK EROSION CONTROL * This requirement applies only to situations where stormwater runoff is discharged to a stream. Calculations show that the Post runoff satisfies the Streambank Erosion Control requirements. Minimum Requirement #6: WETLANDS * This requirement applies only to situations where stormwater discharges directly or indirectly through a conveyance system into a wetland. This project is Timber Thinning. This project will not change the acreage of pervious surface. No wetlands on this property. Minimum Requirement #7: WATER QUALITY SENSITIVE AREAS * Where local governments determine that the Minimum Requirements do not provide adequate protection of water quality sensitive areas, either on -site Or within the basin, more stringent controls shall be required. This property lies in a County designated Aquifer Recharge Area. This is a timber thinning project. Mason County has not imposed additional requirements. Minimum Requirement #8: OFF -SITE ANALYSIS AND MITIGATION * All development projects shall conduct an analysis of off -site water quality impacts resulting from the project and shall mitigate these impacts. The analysis shall extend a minimum of one-fourth of a mile downstream from the project. The off site Post Discharge is calculated to be less than the Pre Discharge. Further analysis is not necessary. Minimum Requirement #9: BASIN PLANNING * An adopted and implemented basin plan may be used to develop requirements for water quality sensitive areas that are tailored to a specific basin. The proposed project is addressing stormwater issues with on -site facilities. No water -shed basin plan is available for use. Minimum Requirement #10: OPERATION AND NIAINTENANCE DURING LOGGING * An operation and maintenance schedule shall be required for all proposed stormwater facilities and BMPs, and the party (or parties) responsible for maintenance and operation shall be identified. The private facility maintenance checklist should be tailored to the facility. The Owner/Contractor will be responsible for operation and maintenance of any stormwater facilities during and after the Timber Thinning. The Owner/Contractor will also inspect the facilities for any evidence of erosion or soil migration and take appropriate action. Grass should be encouraged to grow where logging has been completed. Some timber and native brush will remain behind to assist in greenup. Some areas may be replanted with douglas fir seedlings. Minimum Requirement #11: FINANCIAL RESPONSIBILITY * Performance bonding or other appropriate financial instruments shall be required for all projects to ensure compliance with these standards. We do not expect Mason County to make any requirements regarding performance bonding as a result of the stormwater control plan. II. PLOT PLAN See Civil Drawings III. GENERAL. SITE CONDITIONS SUMMARY See Project Overview for information. IV. SPECIAL REPORTS AND STUDIES N/A V. BASIN AND COMMUNITY PLANNING N/A VI. STORM EVENT DESIGN ASSUMPTIONS STORMWATER CONTROL REVIEW Based on DOE's Stormwater Management Manual: * STORM EVENT Total Acreage Rain Precipitation (in.) Six-month, 24-hour Storm Event Two-year, 24-hour Storm Event Ten-year, 24-hour Storm Event Hundred -year, 24-hour Storm Event Rainfall Choice Hydrograph ** Santa Barbara Urban Hydrograph Method 46 acres 3.00" 4.70" 6.50" 9.30" IA SB U H** EROSION and SEDIMENT CONTROL PLAN DURING THE TIMBER HARVESTING #1 Stabilization and Sediment Trapping All exposed and unworked soils shall be stabilized by suitable application of BMPs. From October 1 to April 30, no soils shall remain unstabilized for more than 2 days. From May 1 to September 30, no soils shall remain unstabilized for more than 7 days. The proposed thinning and harvesting will be with rubber tired skidder. Harvested area boundaries include the 46 acres. All exposed soil will be seeded. A flat bottom ditch will be installed to act as a settling trap, a treatment facility and an infiltration pond for stormwater from the west side of the Bonneville Power Line. Stormwater runoff from the Bonneville Power Line Easement and the easterly property will free flow and infiltrate into the soil. The total runoff allowed to free flow is less than the calculated pre project runoff for the entire 46 acres. #2 Delineate Clearing and Easement Limits In the field, mark clearing limits and/or any eassements, setbacks, sensitive/critical areas and their buffers, trees and drainage cources. The thinning and harvesting operations take place on the entire 46 acres. E,.cc,n- #3 Protection of Adjacent Properties Property adjacent to the project site shall be protected from sediment deposit. The underlying soils are considered to have very little potential for migration. Protecting adjacent property (beyond California Road LLC ownership) from damage caused by sediment migration does not appear to be a problem. Hay or grass mulch may be used where necessary. #4 Timing and Stabilization of Sediment Trapping Measures The ditch and any other BMP's intended to trap sediment on -site shall be constructed as a first step in grading. The proposal is a Timber Thinning, with ground disturbance to be kept at a minimum. The underlying soils are considered to have very little potential for migration. The flat bottom ditch will be installed to act as a sediment trap, treatment facility and infiltration pond. The Contractor shall provide material on -site readily available to immediately stabilize problem areas during periods of inclement weather. As a minimum the Contractor shall have on hand 30 straw/havlales and 4 (20 ft. by 100 ft.) rolls of 6 mil plastic covering. Erosion control measures are to be installed first before any significant Timber fir' ng is started. #5 Cut and Fill Slopes Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion. The Timber Thinning activities do not generate Cut and Fill Slopes. However, the installation of the flat Bottom Ditch will have cut and fill slopes. The side slopes of the ditch are to be no steeper than 3 foot horizontal to 1 foot horizontal. All raw ditch slopes shall be seeded and or mulched immediately after construction. #6 Controlling Off -site Erosion Properties and waterways downstream from development sites shall be protected from erosion due to increases in volume, velocity, and peak flow rate of stormwater runoff from the project site. Because of the gravelly nature of the existing materials, off -site erosion is not anticipated to become an issue. Also the calculated post discharge is less than the calculated pre discharge because of infiltration expected in the flat bottom ditch. #7 Stabilization of Temporary Conveyance Channels and Outlets All temporary on -site conveyance channels shall be designed, constructed and stabilized to prevent erosion from the expected velocity of flow from the 2-year, 24-hour frequency strom for the developed condition. The proposal is a Timber Thinning, with ground disturbance to be kept at a minimum. The underlying soils are considered to have very little potential for migration. The flat bottom ditch will be installed to act as a sediment trap, treatment facility and infiltration pond. EROSION AND STORMWATER CONTROL FOR FOREST PRACTICES ON PROPERTY OWNED BY CALIFORNIA ROAD LLC SECTION 27, TOWNSHIP 21 NORTH, RANGE 4 WEST, WM. PARCEL #421271300000 S TORMWA TER / EROSION CONTROL REPO T ^�4 #8 Storm Drain Inlet Protection All storm drain inlets made operable during construction shall be protected so that stormwater runoff shall not enter the conveyance system without first being filtered or otherwise treated to remove sediment. NA No Storm Drains on site. #9 Underground Utility Construction The construction of underground utilities lines shall be subject to certain criteria. NA No Utilities on site. #10 Construction Access Routes Wherever construction vehicle access routes intersect paved roads, provisions must be made to minimize the transport of sediment (mud) onto the paved road. Construction vehicle access shall be, whenever possible, limited to one route. Stabilized Construction Entrance Detail is shown on the Civil Drawings. #11 Removal of Temporary BMPs All temporary erosion and sediment control BMPs will be removed when final site stabilization is achieved. The ditch is considered to be a permanent erosion and sediment control measure. #12 Dewatering Construction Sites Dewatering devices shall discharge into a sediment trap or sediment pond. NA Groundwater or standing water is not anticipated to become a problem. Lowering the ground water table to facilitate this project will not be an issue. #13 Control of Pollutants Other Than Sediment on Construction Sites All pollutants other than sediment that occur on -site during construction shall be handled and disposed of in a manner that does not cause contamination of stormwater. #14 Maintenance All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of intended function. #15 Financial Liability Mason County has not indicated any requirement for bonding. DRAIN4GE BASIN Entire 46.00 acres Pre Project Runoff Grove gravelly sandy loam (Ab), 0 - 5 percent slope; Hydrologic Soil Group A Remarks Timbered Bonneville Timbered CN# Soil Group 42 A 55 A 42 A Acres 34.96 7.44 3.60 Tc (300' @ 1%; w/ Coeff 0.40 plus 1000' @ 1%; w/ Coeff 0.06) 87.46 minutes DESIGN RESULTS Predeveloped Undeveloped Acreage = 46.00 Storm Event 6-Month Pre Flow -cfs 0.17 Two-year 1.25 Ten-year 100-year 2.90 7.17 DRAINAGE BASIN west of the Bonneville Easement - 34.96 acres Post Developed before flat bottom ditch and infiltration Developed Acreage = 34.96 Remarks CN# Soil Group Acres Timbered 55 A 34.96 Tc (300' @ 1 %; w/ Coeff 0.40 plus 1000' @ 1%; w/ Coeff 0.035) 74.48 minutes Storm Event Post Flow -cfs 6-Month Two-year 0.60 1.86 Ten-year 100-year 4.67 11.98 To reduce the volume of stormwater runoff, after Post Thinning, a flat bottom ditch is proposed for infiltration (floor 1500'x 12' with sideslopes 3' horizonal by I' vertical.) Infiltration rate 10.0 in/hr; Storm Event Post Flow Volume Depth I ,filtration -cfs -cf -ft -cfs 6-Month 0.00 250 0.01 0.60 Two-year 0.00 784 0.04 1.86 Ten-year 0.00 2695 0.14 4.49 100-year 0.00 49044 1.85 8.30 Note: After thinning, any natural depressions that will store and infiltrate stormwater can be used to reduce the width of the flat bottom ditch. (volume for volume). DRAINAGE BASIN including the Bonneville Easement and the property on the east side of the Easement. Totalling 11.04 acres Remarks CN# Soil Group Acres Easement 55 A 7.44 T1hinning 55 A 3.60 Tc (150' @ 1%; w/ Coeff 0.40 DESIGN RESULTS - FREE FLOW POST developed - 11.04 Acres Storm Event 6-Month Post Flow -cfs 0.19 Two-year 0.59 32.34 minutes Ten-year 100-year 1.93 5.30 Pre developed - 46.00 Acres Storm Event 6-Month Two-year Ten-year 100-year Pre Flow -cfs 0.17 1.25 2.90 7.17 Note. The two-year Post Flow is less than half (47 %) of the Pre Flow which satisfies Streambank Erosion Control Requirements. The 10-year and the 100-year Post Flow is 67 % and 74% of the Pre Flow. o.k. CONSTUCTIO\ 117 0 LL APPROVED APPROVAL EXPIRES Occ 00 00 �w CO CO W -CD �w o CD "<( I O Z N Co 'sf- Lu d co o ON R=25' MIN. 4" TO 8" QUARRY SPALLS -1 PROVIDE FULL WIDTH OF INGRESS/EGRESS AREA STABILIZED CONSTRUCTION ENTRANCE N.T.S. x 4' x 14 GA WELDED WIRE FABRIC DR EQUAL 2'x 2 x 5' DOUGL AS FIR STAKE AT 6'-6' MAX SC, (TYP) CONSTRUCTION GEO TEXTILE FOR TEMPORARY SILT FENCE vvvvv`vvv•.i\.V # i.A•A•••A\/•Ai. AAIAAA ♦•NIA/A i nIII A A AAIA111,►:.- • ° o o ° .°000 o000°00000.00 \,\\\\/ 0 0 0 0 0 0°0°0°0 °O°o°o0,00000_0, /`�i�iyi\iyiy`\4 7)4 9iy�\\� 2 ELEVA T i 0/V \/ vv ti S x 12' TRENCH GENERAL NOTES: 1. ALL APPROVALS AND PERMITS REQUIRED BY THE COUNTY SHALL BE OBTAINED BY THE CONTRACTOR PRIOR TO THE START OF CONSTRUCTION. 2, THE CONTRACTOR SHALL BE FULLY RESPONSIBLE FOR THE LOCATION AND PROTECTION OF ALL EXISTING UTILITIES, THE CONTRACTOR SHALL VERIFY THE LOCATIONS PRIOR TO CONSTRUCTION BY CALLING THE UNDERGROUND LOCATE LINE AT 1-800-424-5555 A MINIMUM OF 48 HOURS PRIOR TO ANY EXCAVATION, 3. THE CONTRACTOR IS RESPONSIBLE FOR INSTALLING ANY BURIED UTILITIES AND ELECTRICAL LINES TO APPLICABLE CODES. 4. ALL WORKMANSHIP AND MATERIALS SHALL BE IN ACCORDANCE WITH MASON COUNTY STANDARDS AND THE MOST CURRENT COPY OF THE STATE OF WASHINGTON STANDARD SPECIFICATIONS FOR ROAD BRIDGE AND MUNICIPAL CONSTRUCTION (WSDOTIAPWA. 5. ALL SURVEYING AND CONSTRUCTION STAKING SHALL BE PERFORMED BY AN ENGINEERING OR SURVEYING FIRM CAPABLE OF PERFORMING SUCH WORK. THE ENGINEER OR SURVEYOR DIRECTING SUCH WORK SHALL BE LICENSED BY THE STATE OF WASHINGTON. 6. WHEN PROJECT IS COMPLETE CONTRACTOR SHALL LEAVE THE SITE IN A NEAT AND PRESENTABLE CONDITION, CLEAR OF DIRT AND/OR DEBRIS. 7, THE CONTRACTOR SHALL BE RESPONSIBLE FOR PROVIDING ADEQUATE SAFEGUARDS, SAFETY DEVICES, PROTECTIVE EQUIPMENT, FLAGGERS, AND ANY OTHER NEEDED ACTIONS TO PROTECT THE LIFE, HEALTH, AND SAFETY OF THE PUBLIC AND TO PROTECT PROPERTY IN 'CONNECTION WITH THE PERFORMANCE OF WORK COVERED BY THE CONTRACTOR. ANY WORK WITHIN THE TRAVELED RIGHT-OF-WAY THAT MAY INTERRUPT NORMAL TRAFFIC FLOW SHALL REQUIRE AT LEAST ONE FLAGGER FOR EACH LANE OF TRAFFIC AFFECTED. ALL SECTIONS OF THE WSDOT STANDARD SPECIFICATIONS 1-07.23-TRAFFIC CONTROL SHALL APPLY, 8. THE CONTRACTOR SHALL NOTIFY THE PROJECT ENGINEER IN THE EVENT OR DISCOVERY OF POOR DRAINING SOILS, STANDING GROUNDWATER, OR SEVERE DISCREPANCIES FROM SOIL INFORMATION AS ORIGINALLY REVIEWED. CONSTRUCTION NOTES COMPACTION OF ALL FILL AREAS SHALL BE PER CURRENT WSDOT/APWA SPECIFICATIONS. FILL SHALL BE PROVIDED IN 8" MAXIMUM LIFTS AND SHALL BE COMPACTED TO 95 PERCENT OF ITS MAXIMUM RELATIVE DENSITY. CULVERTS: IF NECESSARY HANCOR HiQ - DOUBLE -WALLED, CORRUGATED, POLYETHYLENE PIPE, WITH A SMOOTH INTERNAL DIAMETER (AASHTO M-294 TYPE-S ADS N-12 PLASTIC PIPE 12"-24"0 ONLY) OR APPROVED EQUAL, COUPLED WITH A COMPANY -PRODUCED PVC COUPLING OR APPROVED EQUAL, 2' x 4' x 14 GA WELDED WIRE FABRIC OR EQU CONSTRUCTION GEE TEXTILE FOR TEMPORAR Y SIL T FENCE 1 1/2' MINUS WASHED ROCK SILT LADEN 8'x 12' TRF NCH -OW NOTES: 2' EXCESS EVERLA TYPICAL CROSS-SECTION 1) SEE STANDARD SPECIFICATION 2-12.3(5), 5, STEEL POSTS MAY BE USED. SUPPORTED BETWEEN POSTS WITH WIRE FILTER FABRIC FENCE- IF NECESSARY N,T,S, LAYOUT OF FLAT BOTTOM DITCH TO BE PLACED PARALLEL TO THE POWER LINE EASEMENT EROSION AND S 'T0 RMWA TER CONTROL. FOR OR FORE S T PRA C TI G ES l �'R OPER T Y O WNL"D BY�' CALIFORNIA ROAD / SECTION 27, TOWNSHIP-LG 21 NORTH, RANGE WEST, WM. PARCEL ##42127130000 CONS TRU0 GT/ON AN.D EROSION CONTROL NOTES & DETAILS EROSION AND SEDIMENT CONTROL REQUIRE THIS THINNING PROJECT WILL DISTURB APPROXIMATELY 46.0A RESPMEND ; THE STORMWATER MANAGEMENT MANUAL - ALL NEW DEVELOPMENT THAT INCLUDES THE CREATION OR ADDITION OF 5,000 SQUARE FEET, OR GREATER, OF NEW IMPERVIOUS SURFACE AREA, AND/OR LAND DISTURBING ACTIVITY OF ONE ACRE OR GREATER COMPLY WITH THE M/N/MUM REQUIREMENTS #1 THROUGH #11. SHALL 1. WHERE APPLICABLE, THIS PROJECT SHALL COMPLY WITH LARGE PARCEL EROSION AND SEDIMENT CONTROL REQUIREMENTS 1 THRU 11 FOUND IN SECTION 1-2.5 OF THE WASHINGTON STATE DEPARTMENT OF ECOLOGY STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN (THE TECHNICAL MANUAL). MRLY 2. WHEN NECESSARY THE PRIVATE CONSTRUCTION VEHICLE ACCESS SHALL BE MAINTAINED TO CO WITH EROSION AND SEDIMENT CONTROL REQUIREMENTS FOUND IN THE WASHINGTON STATE DEPARTMENT OF ECOLOGY 'MANUAL', IF A POTENTIAL FOR TRACKING MUD AND DEBRIS OCCURS, THE SHALL IMMEDIATELY ELIMINATE THE POTENTIAL. CONTRACTOR 3. CONSTRUCTION VEHICLE ACCESS SHALL BE, WHENEVER POSSIBLE, LIMITED TO ONE ROUTE. ACCESS POINTS, WHEN NECESSARY, SHALL BE STABILIZED TO MINIMIZE THE TRACKING OF SEDIMENT ONTO PUBLIC HIGHWAYS. WHENEVER CONSTRUCTION VEHICLE ACCESS ROUTES -INTERSECT PAVED STREETS PROVISION MUST BE MADE TO MINIMIZE THE TRANSPORT OF SEDIMENT ONTO THE PAVED STREET. IF THOROUGHLY CLEANED AT THE END OF EACH DAY. SEDIMENT IS TRANSPORTED ONTO A STREET, THE STREET SHALL BE CLEANED IMMEDIATELY, AND ' 4. SEDIMENT TRAPS, SEDIMENT BARRIERS AND OTHER BMP'S INTENDED TO TRAP SEDIMENT ON SITE SHALL BE CONSTRUCTED AS NECESSARY. STANDARD STORMWATER NOTES: CONSTRUCTION IS IN PROGRESS. 1. A COPY OF THESE APPROVED STORMWATER PLANS MUST BE ON THE JOB SITE W HENEVER 2. THE STORM DRAINAGE SYSTEM SHALL BE CONSTRUCTED ACCORDING TO THESE APPROVED PLANS O FILE WITH THE COUNTY. ANY SIGNIFICANT DEVIATION FROM THESE QUIRE WRITTEN APPROVAL FROM THE COUNTY, NAPPROVED PLANS WILL RE 3. IN ANY AREA WHICH HAS BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND DISTURBING ACTIVITIES AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A PERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE IMMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING, OR OTHER APPROVED EROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR IN QUESTION. GRASS SEEDING ALONE WILL BE ACCEPTABLE ONLY DURING THE MONTHS OF APRIL THROUGH SEPTEMBER, INCLUSIVE. SEEDINSEEDINGMAY PROCEED, HOWEVER, WHENEVER IT IS IN THE INTEREST OF THE DEVELOPER/CONTRACTOR, BUT MUST BE AUGMENTED WITH MULCHING, NETTING, OR OTHER TREATMENT 4• ALL EROSION CONTROL AND STORMWATER FACILITIES SHALL BE REGULARLY INSPECTED AND MAINTAINED BY THE CONTRACTOR DURING THE CONSTRUCTION PHASE OF THE DEVELOPMENT PROJECT. THE FOLLOWING SHALL BE ADHERED TO ON ALL CONSTRUCTION SITES WITH EROSIVE SOILS AND/OR A GRADIENT OF GREATER THAN 2 PERCENT FOR LIMITING EXPOSED SOILS TO EROSIVE PROCESSES. MAY 1 TO SEPTEMBER 30 DRY SEASON THE CLEARING OF LAND, INCLUDING THE REMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO ONLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE LATER THAN OTHERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED, BY NO SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE STABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENTATION CONTROL PLAN, ALL AREAS CLEARED OR OTHERWISE DISTURBED MUST BE N APPROPRIATELY STABILIZED THROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, FREE DRAINING ARTERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED PLAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, FERTILIZING, AND OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE PERFORMED DURING 1 TO MAY 15 AND AUGUST 15 TO OCTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONEMULCHING I THE FOLLOWING PERIODS: MARCH COMPLETION OF THE PROJECT IS IMMINENT AND THE ENVIRONMENTAL CONDITIONS ARE CONDUCIVE SATISFACTORY GROI^VTR. IN 'THE EVENT WHEN PHYSICAL ALTERNATIVE METHOD OF GROUND COVER (SUCHPASMMULCHING ANENT BILIZATION IS N07" POSSIBLTO BLANKE. TS, ETC.) MUST BE INSTALLED BY NO LATER THAN SEPTEMBER G30 PLASTIC SHEETING, EROSION IN THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT ACTIVITIES ARE DISCONTINUED FOR 4 CONSECUTIVE DAYS OR MORE, THE PROPONENT SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION AND SEDIMENTATION CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT LEAST ONCE EVERY WEEK. THE PROPERTY OWNER SHALL BE RESPONSIBLE FOR THE MAINTENANCE AND REPAIR OF ALL EROSION AND SEDIMENTATION CONTROL FACILITIES. OCTOBER 1 TO APRIL 30 (WET SEASON) ON SITES WHERE UNINTERRUPTED CONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE REMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, SHALL BE LIMITED TO AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN THE EVENT A MAJOR STORM IS PREDICTED AND/OR EROSION! SEDIMENT TRANSPORT OFF -SITE IS OBSERVED. ONLY ADDITIONALLY, ALL CLEARED OR DISTURBED AREAS WILL RECEIVE APPROPRIATE PROTECTIVE COVER OR BE OTHERWISE STABILIZED (SUCH AS MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC.) WITHIN 5 DAYS AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED NOT BEING ACTIVELY WORKED. FILTER FABRIC FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC. WILL NOT BE VIEWED AS ADEQUATE COVER IN AND OF THEMSELVES,IF NOT BEING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY STABILIZED IN THE EVENT THAT ANY LAND AREA , 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON THE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENTATION CONTROL ACTIVITY, SHALL IMMEDIATELY CEASE UNTIL SUCH A TIME AS SAID LAND AREA HAS BEEN APPROPRIATELY PROTECTED OR STABILIZED. THE CONTRACTOR SHALL AT ALL TIMES HAVE AVAILABLE FOR THE PROJECT SUFFICIENT QUANTITIES PROTECTIVE COVERING MATERIALS TO IMMEDIATELY STABILIZE ALL DISTURBED AREAS IN CASE THE PROJECT ENGINEER OR COUNTY DIRECTS HIM/HER TO COVER DUE TO OBSERVED MIGRATION OF SOILS OR OF INCLEMENT WEATHER, (REFER TO EROSION CONTROL NOTES #5). INgL } J w W 3 EROSION CONTROL NOTES: STABILIZED CONSTRUCTION ENTRANCE(s) 1. THIS SITE DOES NOT HAVE A STABILIZED ` / MANUAL IS REQUIRED. THE STABILIZED CONSTRUCTION ENTRANCENCE. A ODETAILY OISTRUCTION SHOWN ON THESECCIVILPER THE S.D.O.E. T LOCATION TO BE DETERMINED BY THE CONTRACTOR. 2. SHOULD THE NATURAL EROSION AND SEDIMENTATON CONTROL MEASURES NOT PROVE ADEQUATEDRAWINGS. THE SITE SEDIMENTATION, THE DEVELOPER/CONTRACTOR SHALL INSTALL ADDITIONAL FACILITIES AS NECESSARY TO ADJACENT PROPERTIES, SENSITIVE AREAS, AND/OR THE STORM DRAINAGE SYSTEM, TO CONTROL EROSION AND 3. THE PROPOSED CLEARING LIMITS FOR THE PROPOSED THINNING SHALL BE DEFINED BY THE OWNER OR PROTECT FLAGGING OR OTHER IDENTIFICATION MAY BE USED. THE BUFFER LIMITS SHALL ALSO BE CLEARLY MARKED 4. THE CONTRACTOR SHALL PROVIDE MATERIALS ON -SITE READILY AVAILABLE TO IMMEDIATELY STABILIZETHEIR ASSIGNS. DURING PERIODS OF INCLEMENT WEATHER WHICH RESULT IN EROSION AND SEDIMENT TRANSPORT OFF -SITE. WITH IN MUM THEV CONTRACTOR SHALL HAVE ON HAND 30 STRAW HAY BALES AND FOUR(20 FT, BY 100 FT.) DENUDED AREAS COVERING. TE. MILAS A MINIMUM 5• ALL WORK ASSOCIATED WITH STABILIZING THE DISTURBED AREAS SHALL BE IN ACCORDANCE OWITH OF 6 PLASTIC STORMWATER,ALL MANAGEMENTSOCMANUAL.TH THE MASON COUNTY 6. ALL NECESSARY FACILITIES SHALL BE MAINTAINED ON SITE- TO PREVENT DEBRIS, DUST, AND MUD ON PUBLIC OR PRIVATE PROPERTY OR RIGHT OF WAY. FROM ACCUMULATING SILT FENCES or FILTER FABRIC FENCE - IF 1. FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL AND CUT TO THE LENGTH OF THE OF JOINTS. WHEN JOINTS ARE NECESSARY, FILTER CLOTH SHALLNECESSARY: MINIMUM 6-INCH OVERLAP, AND SECURELY FASTENED AT BOTH ENDS TO POSTS. BARRIER TO AVOID USE 2. POSTS SHALL BE SPACED A MAXIMUM OF 6 FEET APART ANDDRIVEN BEVENPS SPLICED TOGETHER ONLY AT A SUPPORT POST WITH A INCHES), SECURELY INTO THE GROUND (MINIMUM OF 30 3. A TRENCH SHALL BE EXCAVATED APPROXIMATELY 8 INCHES WIDE AND 12 INCHES DEEP ALONG T UPSLOPE FROM THE BARRIER. THIS TRENCH SHALL BE BACKFILLED WITH WASHED GRAVEL. 4. WHEN STANDARD STRENGTH FILTER FABRIC IS USED, A WIRE MESH SUPPORT FENCE SHALL BE F S LINE OF POSTS AND THE UPSLOPE SIDE OF THE POSTS USING HEAVY-DUTY WIRE STAPLES AT LEAST 1-INCH LONG, TIE THE WIRERIG SHALL GROUNDU S INTO THE TRENCH A MINIMUM OF 4 INCHES AND SHALL NOT EXTEND MORE FASTENED SECURELY TO THE INAL ETSURFACE.INTOTHANNE 4 INCHESCRINGS. 5, THE STANDARD STRENGTH FILTER FABRIC SHALL BE STAPLED OR WIRED TO THE FENCE, AND 20 24 TABOVE GROUND BE EXTENDED INTO THE TRENCH. THE FABRIC SHALL NOT EXTEND MORE THAN 24 INCHES ABOVE SHALL SURFACE.EINCHES OF THE FABRIC 6. WHEN EXTRA -STRENGTH FILTER FABRIC AND CLOSER POST SPACING IS USED, THE WIRE MESH THE FENCEORCINAL ELIMINATED. IN SUCH A CASE, THE FILTER FABRIC IS STAPLED OR WIRED DIRECTLY TO THE POSTS PROVISIONS OF ABOVE NOTES APPLYING.SUPPORT MAY BE 7. FILTER FABRIC FENCES SHALL NOT BE REMOVED BEFORE THE UPSLOPE AREA HAS BEEN PERMANENTLY WITH ALL OTHER 8. FILTER FABRIC FENCES SHALL BE INSPECTED IMMEDIATELY AFTER EACH RAINFALL -IND AT LEAST PROLONGED RAINFALL. ANY REQUIRED REPAIRS SHALL BE MADE IMMEDIATELY. STABILIZED. 9. SILT FENCES WILL BE INSTALLED PARALLEL TO ANY SLOPE CONTOURS, DAILY DURING 10. INSTALL DOWNSLOPE OF EXPOSED AREAS, 11. DO NOT DRIVE OVER OR FILL OVER SILT FENCES. SEEDING FOR ALL RAW SLOPES: 1. SEED MIXTURE SHALL BE AS SHOWN BELOW, AND SHALL BE APPLIED AT THE RATE OF 120 POUNDS 2. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL REQUIRE IRRIGATION AND OTHER TO FOSTER AND PROTECT THE ROOT STRUCTURE. PER ACRE, 3. FOR SEED BEDS PLANTED BET{'/EON OCTOBER 31 AND APRIL 30, MAINTENANCE AS NECESSARY GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING). ARMORING OF THE SEED BED WILL BE NECESSARY, (e.g., 4. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF DIKES, SWALES, LEVEL SPREADERS AND SEDIMENT 5• THE SEEDBED SHALL BE FIRM WITH FAIRLY FINE SURFACE, CONTROL MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR BASINS, ACROSS,H ORS E T RIGHT ANGLES THEI SLOPE. ° ACE, FOLLOWING SURFACE ROUGHENING, PERFORM ALL OPERATIONS ESPECIALLY ADJACENT TO WATER BODIES AND WETLANDS, 6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS' RECOMMENDATIONS. AMOUNTS USED SHOULD BE MINIMIZED, USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION CONTROL, OR A COUNTY -APPROVED - ALTERNATE SEED MIXTURE. T1' APPROVED Name Redtop (Agrostis alba) 10 Annual rye (Lolium multiflorun) 40 percent Chewing fescue Percent (Festuca rubra commutate) 40 percent (Jamestown, Banner, Shodow, or Koket) White dutch clover (Trifolium repens) 10 percent 96 Proportions Percent by W_ e1 Pu rlty_ 92 98 97 Percent Germination 90 90 80 90 MULCHING - FOR ALL RAW SLOPES: 1, MULCH MATERIALS USED SHALL BE WOOD FIBER CELLULOSE, AND SHALL BE APPLIED AT T ACRE. 2. MULCH SHALL BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES GREATER THAN 2:1 HE RATE OF 1000 POUNDS PER 3. MULCHING SHALL BE USED IMMEDIATELY AFTER SEEDING OR IN AREAS WHICH CANNOT BE SE SEASON, 4. ALL AREAS NEEDING MULCH SHALL BE COVERED BY NOVEMBER 1, EDED BECAUSE OF THE -311 VARIABLE 3:1 CROSS SECTION Pr FLAT BOTTOM 12' FLAT BOTTOM ❑RIGINAL GROUND 2,0' 3;1 - 6,0' 311 W ra in BERM FROM J DITCH EXCAVATION W DITCH TO BE PLACED PARALLEL TO THE POWER LINE EASEMENT NTS. Zrl CO 0 FOREST PRACTICES APPLICATION STORMWATER/EROSION CONTROL REVIEW I. PROJECT OVERVIEW CALIFORNIA ROAD LLC. OWNERS OF 46 ACRES - The Forest Practices Application is for the thinning of timber from their property located in Section 27, T. 21N., R. 4 W., W.M., Parcel No. 42127 13 00000. Landowner wishes to conduct an uneven aged and salvage type harvest to ensure proper crown spacing and to reduce pockets of disease and defects. All necessary roads and landings are already on the site. Approximately 50 MBF to be harvested. Removal is to be completed using rubber tired skidder. This project is located in an area designated by Mason County as Rural, adjacent and west of the California Road. Topography within the property is relatively flat with no slopes exceeding 10 %. Generally there are no saturated conditions that would lead to sliding. The calculated additional post stormwater runoff caused by the thinning will infiltrate into the ground. Post storm runoff will be less than pre storm runoff. The soil survey of Mason County indicates that the onsite soil type, (USDA1951) is Grove gravelly sandy loam. The Grove Soil is classified as SCS Soils Group A. Group A has the fastest infiltration rate. Experience has shown that the infiltration rate for this soil is: 10 inches per hour. MINIMUM REQUIREMENTS The project shall comply with D.O.E's 1992 Stormwater Management Manual for the Puget Sound Basin, New Development Minimum Requirements #1 through #11. Minimum Requirement #1: EROSION AND SEDIMENT CONTROL Refer to EROSION and SEDIMENT CONTROL PLAN DURING THE TIMBER THINNING located on this sheet. Minimum Requirement #2: PRESERVATION OF NATURAL DRAINAGE SYSTEMS Natural drainage patterns shall be maintained, and discharges from the site shall occur at the natural location, to the maximum extent practicable. There are no identifiable drainage patterns. The property is virtually flat. To retain stormwater on site for infiltration, a ditch will be installed and located on the west side of the Bonneville Power Line. The floor of the ditch will be 12 feet wide with 3.1 slopes and be 2 feet in depth. A burn of excavated materiral will be located on the easterly side of the ditch. See Page 2 of 3 for Details. Minimum Requirement #3: SOURCE CONTROL OF POLLUTION * Source control BMPs shall be applied to all projects to the maximum extent practicable. Source control BMPs shall be selected, designed, and maintained according to an approved manual. The 46 acres is 1 drainage basin. The ditch will act as a settling pond, a treatment facility and also provide total infiltration for the stormwater from the property to the west. Stormwater from the property to the east will continue to flow unrestricted - 'free flow'. The sum of the runoffs will be less than the calculated pre project runoff. Minimum Requirement #4: RUNOFF TREATMENT BMPS * First priority for treatment shall be to infiltrate as much runoff as possible, if site conditions are appropriate and ground water quality will not be impaired. In addition to the treatment received from the flat bottomed ditch, the runoff treatment will also be primarily the natural treatment received by overland flow and infiltration. Minimum Requirement #5: STREAMBANK EROSION CONTROL * This requirement applies only to situations where stormwater runoff is discharged to a stream. Calculations show that the Post runoff satisfies the Streambank Erosion Control requirements. Minimum Requirement #6: WETLANDS * This requirement applies only to situations where stormwater discharges directly or indirectly through a conveyance system into a wetland. This project is Timber Thinning. This project will not change the acreage of pervious surface. No wetlands on this property. Minimum Requirement #7: WATER QUALITY SENSITIVE AREAS * Where local governments determine that the Minimum Requirements do not provide adequate protection of water quality sensitive areas, either on -site or within the basin, more stringent controls shall be required. This property lies in a County designated Aquifer Recharge Area. This is a timber thinning project. Mason County has not imposed additional requirements. Minimum Requirement #8: OFF -SITE ANALYSIS AND MITIGATION * All development projects shall conduct an analysis of off -site water quality impacts resulting from the project and shall mitigate these impacts. The analysis shall extend a minimum of one-fourth of a mile downstream from the project. The off site Post Discharge is calculated to be less than the Pre Discharge. Further analysis is not necessary. Minimum Requirement #9: BASIN PLANNING * An adopted and implemented basin plan may be used to develop requirements for water quality sensitive areas that are tailored to a specific basin. The proposed project is addressing stormwater issues with on -site facilities. No water -shed basin plan is available for use. Minimum Requirement #10: OPERATION AND MAINTENANCE DURING LOGGING * An operation and maintenance schedule shall be required for all proposed stormwater facilities and BMPs, and the party (or parties) responsible for maintenance and operation shall be identified. The private facility maintenance checklist should be tailored to the facility. The Owner/Contractor will be responsible for operation and maintenance of any stormwater facilities during and after the Timber Thinning. The Owner/Contractor will also inspect the facilities for any evidence of erosion or soil migration and take appropriate action. Grass should be encouraged to grow where logging has been completed. Some timber and native brush will remain behind to assist in green up. Some areas may be replanted with douglas fir seedlings. Minimum Requirement #11: FINANCIAL RESPONSIBILITY * Performance bonding or other appropriate financial instruments shall be required for all projects to ensure compliance with these standards. We do not expect Mason County to make any requirements regarding performance bonding as a result of the stormwater control plan. II. PLOT PLAN See Civil Drawings III. GENERAL SITE CONDITIONS SUMMARY See Project Overview for information. IV. SPECIAL REPORTS AND STUDIES N/A V. BASIN AND COMMUNITY PLANNING N/A VI. STORM EVENT DESIGN ASSUMPTIONS STORMWATER CONTROL REVIEW Based on DOE's Stormwater Management Manual: * STORM EVENT Total Acreage Rain Precipitation (in.) Six-month, 24-hour Storm Event Two-year, 24-hour Storm Event Ten-year, 24-hour Storm Event Hundred -year, 24-hour Storm Event Rainfall Choice Hydrograph Santa Barbara Urban Hydrograph Method 46 acres 3.00" 4.70" 6.50" 9.30" IA SBUH** EROSION and SEDIMENT CONTROL PLAN DURING THE TIMBER HARVESTING #1 Stabilization and Sediment Trapping All exposed and unworked soils shall be stabilized by suitable application of BMPs. From October 1 to April 30, no soils shall remain unstabilized for more than 2 days. From May 1 to September 30, no soils shall remain unstabilized for more than 7 days. The proposed thinning and harvesting will be with rubber tired skidder. Harvested area boundaries include the 46 acres. All exposed soil will be seeded. A flat bottom ditch will be installed to act as a settling trap, a treatment facility and an infiltration pond for stormwater from the west side of the Bonneville Power Line. Stormwater runoff from the Bonneville Power Line Easement and the easterly property will free flow and infiltrate into the soil. The total runoff allowed to free flow is less than the calculated pre project runoff for the entire 46 acres. #2 Delineate Clearing and Easement Limits In the field, mark clearing limits and/or any eassements, setbacks, sensitive/critical areas and their buffers, trees and drainage cources. The thinning and harvesting operations take place on the entire 46 acres. #3 Protection of Adjacent Properties Property adjacent to the project site shall be protected from sediment deposit. The underlying soils are considered to have very little potential for migration. Protecting adjacent property (beyond California Road LLC ownership) from damage caused by sediment migration does not appear to be a problem. Hay or grass mulch may be used where necessary. #4 Timing and Stabilization of Sediment Trapping Measures The ditch and any other BMP's intended to trap sediment on -site shall be constructed as a first step in grading. The proposal is a Timber Thinning, with ground disturbance to be kept at a minimum. The underlying soils are considered to have very little potential for migration. The flat bottom ditch will be installed to act as a sediment trap, treatment facility and infiltration pond. The Contractor shall provide material on -site readily available to immediately stabilize problem areas during periods of inclement weather. As a minimum the Contractor shall have on hand 30 straw/hay bales and 4 (20 ft. by 100 ft.) rolls of 6 mil plastic covering. Erosion control measures are to be installed first before any significant Timber Thinning is started. #5 Cut and Fill Slopes Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion. The Timber Thinning activities do not generate Cut and Fill Slopes. However, the installation of the flat Bottom Ditch will have cut and fill slopes. The side slopes of the ditch are to be no steeper than 3 foot horizontal to 1 foot horizontal. All raw ditch slopes shall be seeded and or mulched immediately after construction. #6 Controlling Off -site Erosion Properties and waterways downstream from development sites shall be protected from erosion due to increases in volume, velocity, and peak flow rate of stormwater runoff from the project site. Because of the gravelly nature of the existing materials, off -site erosion is not anticipated to become an issue. Also the calculated post discharge is less than the calculated pre discharge because of infiltration expected in the flat bottom ditch. #7 Stabilization of Temporary Conveyance Channels and Outlets All temporary on -site conveyance channels shall be designed, constructed and stabilized to prevent erosion from the expected velocity of flow from the 2-year, 24-hour frequency strom for the developed condition. The proposal is a Timber Thinning, with ground disturbance to be kept at a minimum. The underlying soils are considered to have very little potential for migration. The flat bottom ditch will be installed to act as a sediment trap, treatment facility and infiltration pond. EROSION AND STORMWATER CONTROL FOR FOREST PRACTICES ON PROPERTY OWNED BY CALIFORNIA ROAD LLC SECTION 27, TOWNSHIP 21 NORTH, RANGE 4 WEST, WM. PARCEL #4212 71300000 S TORMWA TER / EROSION CONTROL REPORT #8 Storm Drain Inlet Protection All storm drain inlets made operable during construction shall be protected so that stormwater runoff shall not enter the conveyance system without first being filtered or otherwise treated to remove sediment. NA No Storm Drains on site. #9 Underground Utility Construction The construction of underground utilities lines shall be subject to certain criteria. NA No Utilities on site. #10 Construction Access Routes Wherever construction vehicle access routes intersect paved roads, provisions must be made to minimize the transport of sediment (mud) onto the paved road. Construction vehicle access shall be, whenever possible, limited to one route. Stabilized Construction Entrance Detail is shown on the Civil Drawings. #11 Removal of Temporary BMPs All temporary erosion and sediment control BMPs will be removed when final site stabilization is achieved. The ditch is considered to be a permanent erosion and sediment control measure. #12 Dewatering Construction Sites Dewatering devices shall discharge into a sediment trap or sediment pond. NA Groundwater or standing water is not anticipated to become a problem. Lowering the ground water table to facilitate this project will not be an issue. #13 Control of Pollutants Other Than Sediment on Construction Sites All pollutants other than sediment that occur on -site during construction shall be handled and disposed of in a manner that does not cause contamination of stormwater. #14 Maintenance All terporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of intended function. #15 Financial Liability Mason County has not indicated any requirement for bonding. DRAINAGE BASIN Entire 46.00 acres Pre Project Runoff Grove gravelly sandy loam (Ab), 0 - 5 percent slope; Hydrologic Soil Group A Remarks Timbered Bonneville Timbered CN# Soil Group 42 A 55 A 42 A Acres 34.96 7.44 3.60 Tc (300' © 1 %; w/ Coeff 0.40 plus 1000' @ 1 %; w/ Coeff 0.06) 87.46 minutes DESIGN RESULTS Predeveloped Undeveloped Acreage = 46.00 Storm Event 6-Month Pre Flow -cfs 0.17 Two-year 1.25 Ten-year 100-year 2.90 7.17 DRAINAGE BASIN west of the Bonneville Easement - 34.96 acres Post Developed before flat bottom ditch and infiltration Developed Acreage = 34.96 Remarks CN# Soil Group Acres Timbered 55 A 34.96 Tc (300' @ 1 %; w/ Coeff 0.40 plus 1000' @ 1%; w/ Coeff 0.035) 74.48 minutes Storm Event 6-Month Two-year Ten-year 100-year Post Flow -cfs 0.60 1.86 4.67 11.98 To reduce the volume of stormwater runoff, after Post Thinning, a flat bottom ditch is proposed for infiltration (floor 1500'x 12' with sideslopes 3' horizonal by 1' vertical.) Infiltration rate 10.0 in/hr; Storm Event Post Flow Volume Depth - Infiltration - cfs - cf -ft - cfs 6-Month 0.00 250 0.01 0.60 Two-year 0.00 784 0.04 1.86 Ten-year 0.00 2695 0.14 4.49 100-year 0.00 49044 1.85 8.30 Note: After thinning, any natural depressions that will store and infiltrate stormwater can be used to reduce the width of the flat bottom ditch. (volume for volume). DRAINAGE BASIN including the Bonneville Easement and the property on the east side of the Easement. Totalling 11.04 acres Remarks Easement Thinning Tc CN# Soil Group Acres 55 A 7.44 55 A 3.60 (150' © 1%; w/ Coeff 0.40 DESIGN RESULTS - FREE FLOW POST developed - 11.04 Acres Storm Event 6-Month Two-year Post Flow -cfs 0.19 0.59 32.34 minutes Ten-year 100-year 1.93 5.30 Pre developed - 46.00 Acres Storm Event 6-Month Two-year Ten-year 100-year Pre Flow -cfs 0.17 1.25 2.90 7.17 Note: The two-year Post Flow is less than half (47 %) of the Pre Flow which satisfies Streambank Erosion Control Requirements. The 10-year and the 100-year Post Flow is 67 % and 74% of the Pre Flow. o.k. CO\STU 0 L APPROVED >- mo r- ~o� �zLLo LLJ CL �(f)u-,O �zz z �CO z�o wow APPROVAL EXPIRES Q c.D z U Op Z N. c p coo OD CM to o W �`nrn oo ZYpcipo Q -1 Z= -9 - z I i d cl-i5 q� cci�v U