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Preliminary Drainage Crystal Springs Estates Yelm, WA Preliminary Drainage Report ~uiy Zoos PRELIMINARY DRAINAGE REPORT Project Information Yelm, Washington July 2005 Project: Crystal Springs Estates Prepared for: Rainier General Development Contact: Doug Bloom P.O. Box 627 Rainier, WA 98576 (360) 446-3083 Reviewing Agency Jurisdiction: Project Number: Project Contact Project Engineer Prepared by: Contact: OE Project No. File Name: ~wo~ W~ap~~oo ~ ~ 1or~ -~ _ 3T4C7 ,. /, City of Yelm Tami Merriman (360) 458-8496 Olympic Engineering 1252 Devon Loop NE Olympia, WA 98506 (360) 870-2561 FAX (360) 705-9361 Chris M. Merritt, P.E. 05016 05016_pdr.doc PROJECT ENGINEERS CERTIFICATION: I hereby certify that this Preliminary Drainage Report for the Crystal Springs Estates Plat in the City of Yelm, Washington has been prepared by me or under my supervision and meets the intent of the Thurston County Drainage Design and Erosion Control Manual (DDECM) and/or the WSDOE 1992 Stormwater Management Manual, unless noted otherwise, and normal standards of en meerin ractice. I understand that the urisdiction does E'j(~}}tpS fEtt410~~ not and will no tassume liability for the sufficiency, suit bility, or performance of drainage facilities designed for this development. 1 Table of Contents PART I STORM DRAINAGE REPORT ........................................................ 2 SECTION 1 -PROPOSED PROJECT DESCRIPTION ...................... ......... 2 SECTION 2 -EXISTING CONDITIONS ............................................ ......... 3 SECTION 3 -INFILTRATION RATES /SOILS REPORT ................. ......... 4 SECTION 4 - WELLS AND SEPTIC SYSTEMS ................................ ......... 4 SECTION 5 -FUEL TANKS ............................................................... ......... 4 SECTION 6 - SUB-BASIN DESCRIPTION ........................................ ......... 4 SECTION 7 -ANALYSIS OF 100-YEAR FLOOD .............................. ......... 5 SECTION 8 -AESTHETIC CONSIDERATIONS FOR FACILITIES ......... 5 SECTION 9 -DOWNSTREAM ANALYSIS ........................................ ......... 5 SECTION 10 -COVENANTS, DEDICATIONS, EASEMENTS .......... ......... 5 SECTION 11 -ARTICLES OF INCORPORATION .............................. ......... 5 PART II EROSION CONTROL REPORT ....................................................6 SECTION 1 - CONSTRUCTION SEQUENCE AND PROCEDURE .......... 6 SECTION 2 -TRAPPING SEDIMENT ........................................................ 6 SECTION 3 -PERMANENT EROSION CONTROL ................................... 7 SECTION 4 - GEOTECHNICAL ANALYSIS AND REPORT ..................... 7 SECTION 5 -INSPECTION SEQUENCE ................................................... 7 SECTION 6 - CONTROL OF POLLUTANTS .............................................. 8 PART III MAINTENANCE PLAN ................................................................9 SECTION 1 -REQUIRED MAINTENANCE ...............................................9 SECTION 2 -RESPONSIBLE ORGANIZATION ...................................... 20 SECTION 3 -VEGETATION MANAGEMENT PLAN .............................. 20 SECTION 4 - SOURCE CONTROL ............................................................ 20 APPENDICES Appendix 1-Preliminary Drainage Calculations Appendix 2- Vicinity Map Appendix 3 -Drainage Basin Map Appendix 4 -Soils Report ll PART I STORM DRAINAGE REPORT SECTION 1 -PROPOSED PROJECT DESCRIPTION Prepared for: Rainier General Development Contact: Doug Bloom P.O. Box 627 Rainier, WA 98576 (360) 446-3083 Parcel Number: Total Site Area: Zoned: Site Address: Required Permits: Section, Township, Range 22718330102,22718330304 5.60 Acres R-6 1311 & 1405 Crystal Springs Road NW Yelm, WA 98597 Grading, Utility, Building, etc. Section 18 Township 17 North Range 2 East, W.M. Project Overview The project site is located adjacent to Crystal Springs Road in Yelm. The applicant proposes to construct a new public roadway through the parcel connecting to Crystal Springs Road and to install utility services to serve 23 single family lots. Access to the proposed lots will be from the new public roadway The development will be constructed in one phase. Construction will include clearing and grading of the site, storm drainage improvements, underground utilities, and paving. City of Yelm sanitary sewer and water mains will be extended into the site to provide services to the residential lots. Stormwater facilities will be constructed that consist of proposed a biofiltration swale and wetvault for storm water treatment along with an infiltration pond and underground drainrock gallery for retention and infiltration of stormwater runoff created by the new development. For stormwater design purposes, the proposed development has been subdivided into two drainage sub-basins (see preliminary calculations in Appendix). Stormwater Treatment: A proposed biofiltration swale in Basin `A' and a proposed wetvault in Basin `B' will provide treatment of Stormwater runoff. The proposed treatment facilities exceed the minimum WSDOE requirements. See Preliminary Drainage Calculations in Appendix. Stormwater Storage: All Stormwater runoff from the new roadway and the Crystal Springs Road frontage will be collected in a series of catch basins and conveyed to either the biofiltration Swale or wetvault for treatment. Discharge from the biofiltration Swale in Basin `A' will flow into an infiltration pond; and discharge from the wetvault in Basin `B' will flow into an underground drainrock gallery for Stormwater retention and infiltration to groundwater. The proposed Stormwater storage facilities exceed the minimum storage requirements per the WSDOE. See Preliminary Drainage Calculations in Appendix. Roof Runoff: Roof runoff from each residential home will be tightlined to individual lot infiltration drainrock drywells. The drywells shall be sized per Table 8.2 in the DDECM using a soil hydrologic Group "A" classification (125 cf per 1,000 sf of roof area). SECTION 2 -EXISTING CONDITIONS The project site contains a single family residence with several outbuildings. The home will remain and some of the outbuildings will be demolished. Site relief is rolling, rising from the east at Crystal Springs Road a distance of 1501ineal feet to the property's highest elevation of 332 ft. The site then slopes to the west approximately 140 lineal feet to a low point of 324 ft. Terrain then rises to the west a distance of 200 lineal feet to an elevation of 326 ft., and then continues to slope away in a westerly direction to a low point of 309 ft. at Yelm Creek. Yelm Creek defines the western property line. Site vegetation consists of a small 2nd growth fir tree grove near the northeastern property corner, field grasses with isolated conifer and deciduous trees on the uplands, and thick indigenous brush and field grass ground cover bordering Yelm Creek on the lowlands. The project site is bounded to the east by Crystal Springs Road NW, developed residential property to the south and west, and residential property to the north. See Section 6 for description of off-site drainage to the property, if any. The project site is located in an aquifer sensitive area based on review of Thurston County Comprehensive Plan Map M-8. This project will comply with the Stormwater treatment requirements of the DOE Manual. SECTION 3 -INFILTRATION RATES /SOILS REPORT The Soil Conservation Service (SCS) soil survey of Thurston County classifies the on-site soils as Spanaway Gravelly Sandy Loam (Hydrologic Group A). Soil testing confirmed the Spanaway series classification. Two test pits were excavated by backhoe to a maximum depth of 156" below existing grade and two double ring infiltration tests were completed. A 15"/hr and 20"/hr rate will be used for design in Basins A and B, respectively. Test pit soil log data sheets and infiltration test results are included in the Appendix of this report. SECTION 4 -WELLS AND SEPTIC SYSTEMS No wells within 200-feet of the project boundaries were found during a site investigation. Water and sanitary sewer services for the proposed project will be provided by the City of Yelm. A septic system currently serves the existing home. This will be abandoned per Department of Health standards during development. SECTION 5 -FUEL TANKS No fuel tanks were located during our site inspection or soils work. The latest "LUST" list (Leaking Underground Storage Tank) was reviewed and no listing for the subject site was found. SECTION 6 -SUB-BASIN DESCRIPTION The project site is located within the Nisqually River Drainage Basin per the Thurston County Geodata Center. From our site visit there were no signs of existing drainage swales or channels on the proposed property. There did not appear to be a significant amount of off-site runoff onto the site from the adjacent north, east, and south properties. Yelm Creek defines the western property line of the subject project. The Coot Company has determined the stream to be Type III and the associated wetland to be Category 3. A 200' shoreline jurisdiction boundary has been established along with a 50' wetland/stream setback buffer. Hazardous material handling or transportation is not expected in the area tributary to the on-site detention facility. SECTION 7 -ANALYSIS OF 100-YEAR FLOOD Approximately 40' on either side of Yelm Creek appears to be within the 100-year floodplain. SECTION 8 -AESTHETIC CONSIDERATIONS FOR FACILITIES All disturbed pervious areas including the storm drainage and open space tracts will be vegetated and landscaped. SECTION 9 -DOWNSTREAM ANALYSIS Preliminary calculations for the project stormwater treatment and storage systems are included in the Appendix of this report. All stormwater runoff generated by site development will be treated, stored, and infiltrated on-site. In the event of a failure, storm water will overflow through the catch basin rims and temporarily back onto the public roadway in Basin `B' and overflow to Yelm Creek in Basin `A'. Adjacent properties should not be affected due to failure of the proposed stormwater system. SECTION 10 -COVENANTS, DEDICATIONS, EASEMENTS On-site drainage facilities will require routine maintenance. A maintenance agreement will be prepared and finalized prior to final project approval. SECTION 11 -PROPERTY OWNERS ASSOCIATION ARTICLES OF INCORPORATION In light of the residential nature of this project, special covenants covering landscape, maintenance, signage, stormwater and site maintenance may be put in place at the time of final platting. The Owner's and/or their representatives will perform maintenance of these private storm drainage facilities. PART II EROSION CONTROL REPORT SECTION 1 -CONSTRUCTION SEQUENCE AND PROCEDURE Proposed development of the residential property will include site grading and erosion control measures designed to contain silt and soil within the project boundaries during construction until permanent erosion control is in place. Erosion/sedimentation control will be achieved by a combination of structuraUvegetative cover measures and construction practices tailored to fit the site. Best Construction Management Practices (BMP's) will be employed to properly clear and grade the site and to schedule construction activities. Before any construction begins on-site, erosion control facilities shall first be installed. The planned construction sequence is as follows: 1. Install rock construction entrance. Use 4" to 8" diameter spalls with 12" minimum depth. 2. Install filter fabric fencing, where appropriate. 3. Construct temporary sedimentation basins, if necessary. 4. Clear site (grubbing and rough grading). 5. During November 1 through March 31, all disturbed areas greater than 5,000 sf that are to be left un-worked for more than twelve (12) hours, shall be stabilized by one of the following: mulch, sodding, or plastic covering. 6. Install underground utilities (cable, telephone, power, etc.). 7. If applicable, provide catch basin protection by installing filter fabric and hay bales around all inlets to drainage system. 8. After paving is complete, install landscape, sod and/or seed, and mulch all disturbed areas. 9. Maintain all erosion control facilities until the entire site is stabilized and silt runoff ceases. 10. Designate an area for washing of equipment and concrete trucks to control the runoff and eliminate entry into storm drainage systems. SECTION 2 -TRAPPING SEDIMENT A stabilized construction entrance shall be installed at the entrance to the proposed plat to prevent vehicles from tracking soil away from the disturbed areas. If sediment is tracked onto public roadways, sediment shall, on a daily basis, be swept or shoveled from paved surfaces and not washed down into the roadside storm drainage system. The contractor shall not be allowed to leave disturbed areas greater than 5,000 sf that are to be left un-worked for more than twelve (12) hours uncovered during the rainy season from November 1 through March 31. Mulch, sodding or plastic covering will be used to prevent erosion in these areas. During construction, the contractor will also be required to install filter fabric fencing as needed, per the erosion control plan and as directed by the engineer, or City Inspector SECTION 3 -PERMANENT EROSION CONTROL & SITE RESTORATION All disturbed areas will be paved, covered with a building or landscaped with grass, shrubbery or trees. SECTION 4 -GEOTECHNICAL ANALYSIS AND REPORT There are no slopes exceeding 15% on-site, therefore, a geotechnical analysis was deemed unnecessary. SECTION 5 -INSPECTION SEQUENCE In addition to the normal City inspections, the Project Engineer shall inspect the facilities related to storm water treatment, erosion control, storage and conveyance during construction. At a minimum, the following items shall be inspected at the time specified: 1. The erosion control facilities shall be inspected before the start of clearing and grading to ensure the following structures are in place: a. Construction Entrance b. Filter Fabric Fences 2. The conveyance systems will be inspected after construction of the facility, but before the project is completed to ensure the following are in working order: a. Road Drainage Conveyance System b. Biofiltration Swales c. Infiltration Pond d. Infiltration Gallery e. Wetvault 3. The permanent site restoration measures should be inspected after landscaping is completed. A final inspection shall be performed to verify final grades, settings of structures and all necessary information to complete Engineer's Construction Inspection Report Form and Residential Agreement to maintain stormwater facilities. These forms must be completed prior to final public works construction approval. SECTION 6 -CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS Washout from a concrete truck shall not be dumped into the storm drain, or onto soil or pavement, which carries stormwater runoff: It can be dumped into a designated area to be later backfilled or hardened and broken up for disposal into a dumpster. The Contractor will be required to designate a wash down area for equipment and concrete trucks. PART III MAINTENANCE PLAN SECTION 1 -REQUIRED MAINTENANCE The following pages contain maintenance needs for most of the components that are part of your drainage system, as well as for some components that you may not have. Let us know if there are any components that are missing from these pages. Ignore the requirements that do not apply to your system. You should plan to complete a checklist for all system components on the following schedule: 1.Monthly from November through April. 2.Once in late summer (preferably September). 3.After any major storm (use 1" in 24 hours as a guideline) items marked "S" only. Using photocopies of these pages, check off the problems you looked for each time you did an inspection. Add comments on problems found and actions taken. Keep these "Checked" sheets in your files, as they will be used to write your annual report (due in May). Some items do not need to be looked at every time an inspection is done. Use the suggest frequency at the left of each item as a guideline for your inspection. You may call the jurisdiction for technical assistance. Please do not hesitate to call, especially if you are unsure whether a situation you have discovered may be a problem. ATTACHMENT `A' Inspection Period: MAINTENANCE PROGRAM COVER SHEET Number of Sheets Attached: Date Inspected: Inspector's Signature: ATTACHMENT "A": MAINTENANCE PROGRAM Maintenance Checklist for Conveyance Systems (Pipes, Ditches and Swales) Frequency Drainage ~ Req'd Problem Conditions To Check For Conditions That Should Exist System Feature M.S. Pipes ~/ Sediment & Accumulated sediment that Pipe cleaned of all sediment and debris exceeds 20% of the diameter debris. of the pipe. M ~ Vegetation Vegetation that reduces free All vegetation removed so water movement of water through flows freely. pipes. A ~ Damaged Protective coating is Pipe repaired or replaced. (rusted, bent damaged, rust is causing or crushed) more than 50% deterioration to any part of pipe. M ~ Any dent that significantly Pipe repaired or replaced. impedes flow (i.e., decreases the cross section azea of pipe by more then 20%). M ~I Pipe has major cracks or Pipe repaired or replaced. tears allowing groundwater leakage- M.S. Swales ~ Trash & Dumping of yard wastes such Remove trash and debris and debris as grass clippings and dispose as prescribed by County branches into Swale. Waste Management Section. Unsightly accumulation of non-degradable materials such as glass, plastic, metal, foam and coated paper. M ~ Sediment Accumulated sediment that Swale cleaned of all sediment and buildup exceeds 20% of the design debris so that it matches design. depth. M ~ Vegetation Grass cover is sparse and Aerate soils and reseed and mulch not growing weedy or areas are bare areas. Maintain grass height or over-grown overgrown with woody at a minimum of 6" for best vegetation. stormwater treatment. Remove woody growth, recontour and reseed as necessary. M ~ Conversion Swale has been filled in or If possible, speak with homeowner by home- blocked by shed, woodpile, and request that Swale area be owner to shrubbery, etc. restored. Contact County to incompatible report problem if not rectified use voluntarily. A ~ Swale does Water stands in Swale or A survey may be needed to check not drain flow velocity is very slow. grades. Grades need to be in 1% Stagnation occurs. range if possible. If grade is less than 1%, under drains may need to be installed. If you are unsure whether a problem exists, please contact the Jurisdiction and ask for technical assistance. ATTACHMENT "A" (CONTINUED) Maintenance Checklist for Catch Basins and Inlets Frequency Drainage J Req'd Problem Conditions To Check For Conditions That Should Exist System Feature M,S General J Trash, Trash or debris in front of the No trash or debris located debris, and catch basin opening is blocking immediately in front of catch sediment capacity by more than 10%. basin opening. Grate is kept in or on clean and allows water to basin enter. M J Sediment or debris (in the No sediment or debris in the basin) that exceeds 1/3 the catch basin. Catch basin is depth from the bottom of basin dug out and clean. to invert of the lowest pipe into or out of the basin. M,S J Trash or debris in any inlet or Inlet and outlet pipes free of pipe blocking more than 1/3 of trash or debris. its height. M ~ Structural Corner of frame extends more Frame is even with curb. damage to than 3/4 inch past curb face frame into the street (if applicable). and/or top slab M J Top slab has holes larger than 2 Top slab is free of holes and square inches or cracks wider cracks. than 1/4 inch (intent is to make sure all material is running into the basin). M J Frame not sitting flush on top Frame is sitting flush on top slab, i.e., separation of more slab. than 3/4 inch of the frame from the top slab. A J Cracks in Cracks wider than 1/2 inch and Basin replaced or repaired to basin longer than 3 feet, any evidence design standards. Contact a walls/ of soil particles entering catch professional engineer for bottom basin through cracks, or evaluation. maintenance person judges that structure is unsound. A J Cracks wider than 1/2 inch and No cracks more than 1/4 inch longer than 1 foot at the joint of wide at the joint of inletloutlet any inlet/outlet pipe or any pipe. evidence of soil particles entering catch basin through cracks. A J Settlement Basin has settled more than 1 Basin replaced or repaired to /misalign- inch or has rotated more than 2 design standards. Contact a went inches out of alignment. professional engineer for evaluation. Frequency Drainage System Feature J Req'd Problem Conditions To Check For Conditions That Should Exist M,S J Fire hazard Presence of chemicals such No color, odor, or sludge. Basin is or other as natural gas, oil, and dug out and clean. pollution gasoline. Obnoxious color, odor, or sludge noted. M,S J Outlet pipe is Vegetation or roots growing No vegetation or mot growth clogged with in inlet/outlet pipe joints present. vegetation that is more than six inches tall and less than six inches apart. If you are unsure whether a problem exists, please contact the Jurisdiction and ask for technical assistance. Comments: Kev A =Annual (March or April preferred) M =Monthly (see schedule) S =After major storms ATTACHMENT "A" (CONTINUED) Maintenance Checklist for Grounds (Landscaping) Frequency Drainage ~ Problem Conditions to Check For Conditions That Should Exist System Feature M General ~ Weeds Weeds growing in more than Weeds present in less than 5% of (nonpoisonous) 20% of the landscaped area the landscaped area. (trees and shrubs only). M ~ Safety hazard Any presence of poison iry or No poisonous vegetation or other poisonous vegetation or insect nests present in insect nests. landscaped area. M,S ~ Trash or litter See Ponds Checklist. See Ponds Checklist. M,S ~ Erosion of Noticeable rills are seen in Causes of erosion are identified Ground Surface landscaped areas. and steps taken to slow down/spread out the water. Eroded areas are filled, contoured, and seeded. A Trees and ~ Damage Limbs or parts of trees or Trim trees/shrubs to restore shrubs shrubs that are split or shape. Replace trees/shrubs broken which affect more with severe damage. than 25% of the total foliage of the tree or shrub. M ~l Trees or shrubs that have Replant tree, inspecting for been blown down or knocked injury to stem or mots. Replace over. if severely damaged. A ~ Trees or shrubs which are Place stakes and rubber-coated not adequately supported or ties around young trees/shrubs are leaning over, causing for support. exposure of the roots. If you are unsure whether a problem exists, please contact the Jurisdiction and ask for technical assistance. Comments: Kev A =Annual (March or April preferred) M =Monthly (see schedule) S =After major storms ATTACHMENT "A" (CONTINUED) Maintenance Checklist for Energy Dissipaters Freq. Drainage ~ Problem Conditions to Check For Conditions That Should Exist System Feature A Rock Pad ~ Missing or Only one layer of rock exists Replace rocks to design moved rock above native soil in area 5 standard. square feet or larger, or any exposure of native soil. A Rock-filled Missing or Trench is not full of rock. Add large rock (t301b. each) so trench for moved rock that rock is visible above edge discharge ftom of trench. pond M Dispersion Pipe plugged Accumulated sediment that Pipe Cleaned/flushed. trench with sediment exceeds 20% of the design depth. M Perforations Over 1/2 of perforations in Clean or replace perforated pipe. plugged pipe are plugged with debris and sediment. M,S Not discharging Visual evidence of water Trench must be redesigned or water properly discharging at concentrated rebuilt to standard. Elevation of points along trench (normal lip of trench should be the same condition is a "sheetflow" of (flat) at all points. water along trench). Intent is to prevent erosion damage. M,S Water flows out Maintenance person Facility must be rebuilt or top of observes water flowing out redesigned to standards. Pipe is "distributor" during any storm less than probably plugged or damaged catch basin the design storm or its and needs replacement. causing or appears likely to cause damage. M,S Receiving area Water in receiving area is Stabilize slope with grass or over-saturated causing or has potential of other vegetation, or rock if causing landslide. condition is severe. If you are unsure whether a problem exists, please contact the Jurisdiction and ask for technical assistance. Comments: Key: A =Annual (March or April preferred) M =Monthly (see schedule) S =After major storms ATTACHMENT "A" (CONTINUED) Maintenance Checklist for Ponds Freq. Drainage ~I Problem Conditions to Check For Conditions That Should Exist System Feature M.S. General .~ Trash & debris Dumping of yard wastes Remove trash and debris and buildup in pond such as grass clippings and dispose as prescribed by County branches into basin. Waste Management Section Unsightly accumulation of non-degradable materials such as glass, plastic, metal, foam, and coated paper. M.S. ~ Trash rack Bar screen over outlet more Replace screen. Remove trash plugged or than 25% covered by debris and debris and dispose as missing or missing. prescribed by County Waste Management Section. M ~ Poisonous Any poisonous vegetation Remove poisonous vegetation. vegetation which may constitute a Do not spray chemicals on hazard to the public. vegetation without obtaining Examples of poisonous guidance from the Cooperative vegetation include: tansy Extension Service and approval ragwort, poison oak, from the County. stinging nettles, devilsclub M.S. ,~ Fire hazard or Presence of chemicals such Find sources of pollution and pollution as natural gas, oil, and eliminate them. Water is free gasoline, obnoxious color, from noticeable color, odor, or odor, or sludge noted. contamination. M .~ Vegetation not For grassy ponds, grass For grassy ponds, selectively growing or is cover is sparse and weedy thatch, aerate, and reseed ponds. overgrown or is overgrown. For Grass cutting unnecessary unless wetland ponds, plants are dictated by aesthetics. For sparse or invasive species wetland ponds, hand-plant are present. nursery-grown wetland plants in bare areas. Contact the Cooperative Extension Service for direction in invasive species such as purple looseime and reed canary grass. Pond bottoms should have uniform dense coverage of desired plant species. M .~ Rodent holes Any evidence of rodent Rodents destroyed and dam or holes if facility is acting as berm repaired. Contact the a dam or berm, or any Thurston County Health Dept. evidence of water piping for guidance. through dam or berm via rodent holes. M Insects When insects such as wasps Insects destroyed or removed and hornets interfere with from site. Contact Cooperative maintenance activities, or Extension Service for guidance. when mosquitoes become a nuisance. A ~ Tree Growth Tree growth does not allow Trees do not hinder maintenance maintenance access or activities- Selectively cultivate interferes with maintenance trees such as alders for firewood. activity (i.e., slope mowing, silt removal, or ui ment Freq. Drainage ~ Problem Conditions to Check For Conditions That Should Exist System Feature movements). If trees are not interfering with access, leave trees alone. M Side slopes of ~I Erosion on Check around inlets and Find causes of erosion and pond berms or at outlets for signs of erosion. eliminate them. Then slopes entrance/ Check berms for signs of should be stabilized by using exit sliding or settling. Action appropriate erosion control is needed where eroded measure(s); e.g., rock damage over 2 inches deep reinforcement, planting of grass, and where there is potential compaction. for continued erosion. M Storage area .~ Sediment Accumulated sediment that Sediment cleaned out to designed buildup in pond exceeds 10% of the pond shape and depth; pond designed pond depth. reseeded if necessary to control Buried or partially buried erosion. outlet structure probably indicates significant sediment deposits. A Pond dikes .~ Settlements Any part of dike which has Dike should be built back to the settled 4 inches lower than design elevation. the design elevation. A Emer-gency ~ Rock missing Only one layer of rock Replace rocks to design overflow/ exists above native soil in standards. spillway area 5 square feet or larger, or any exposure of native soil. One time Emer-gency ~ Overflow Side of pond has no area Contact County for guidance. overflow/ missing with large rocks to handle spillway emergency overflows. If you are unsure whether a problem exists, please contact the Jurisdiction and ask for technical assistance. Comments: Key: A =Annual (March or April preferred) M =Monthly (see schedule) S =After major storms ATTACHMENT "A" (CONTINUED) Maintenance Checklist for Infiltration Systems Frequency Drainage J Problem Conditions to Check For Conditions That Should Exist System Feature M,S General Trash & debris See Maintenance Checklist for See Maintenance Checklist for buildup in Ponds. Ponds. pond M Poisonous See Maintenance Checklist for See Maintenance Checklist for vegetation Ponds. Ponds. M,S Fire hazard or See Maintenance Checklist for See Maintenance Checklist for pollution Ponds. Ponds. M Vegetation not See Maintenance Checklist for See Maintenance Checklist for growing or is Ponds. Ponds. overgrown M Rodent holes See Maintenance Checklist for See Maintenance Checklist for Ponds. Ponds. M Insects See Maintenance Checklist for See Maintenance Checklist for Ponds. Ponds. A Storage J Sediment A soil texture test indicates Sediment is removed and/or area buildup in facility is not working at its facility is cleaned so that system designed capabilities or was infiltration system works incorrectly designed. according to design. A sediment trapping azea is installed to reduce sediment transport into infiltration area. A J Storage area A soil texture test indicates Additional volume is added drains slowly facility is not working at its through excavation to provide (more than 48 designed capabilities or was needed storage. Soil is aerated hours) or incorrectly designed. and rototilled to improve overIlows drainage. Contact the City for information on its requirements regarding excavation. M J Sediment Any sediment and debris filling Clean out sump to design trapping area area to 10% of depth from sump depth. bottom to bottom of outlet pipe or obstructing flow into the connector pipe. One Time J Sediment Stormwater enters infiltration Add a trapping area by trapping area area directly without constructing a sump for settling not present treatment. of solids. Segregate settling area from rest of facility. Contact City for guidance. M Rock filters J Sediment and By visual inspection little or no Replace gravel in rock filter. debris water flows through filter during heavy rain storms. S Infiltration J Infiltration Standing Water in Inspection Excavate bottom of trench as Trenches Failure Well After 48 hours after necessary but at least 3 feet. storm or Overflow during Replace with crushed rock. Storms Check pretreatment systems for effectiveness. Check tributary area for sediment sources. If you are unsure whether a problem exists, please contact the Jurisdiction and ask for technical assistance. Comments: Key A =Annual (March or April preferred) M =Monthly (see schedule) S =After major storms SECTION 2 -RESPONSIBLE ORGANIZATION The Homeowner's Association shall be responsible for the operation and maintenance of all on-site drainage facilities. SECTION 3 -VEGETATION MANAGEMENT PLAN All disturbed pervious areas within the site will be landscaped to provide an aesthetically pleasing environment. SECTION 4 -SOURCE CONTROL Warning signs (e.g., "Dump No Waste -Drains to Groundwater") will be embossed or painted on or adjacent to all storm drain inlets and will be repainted periodically as necessary. Appendix I Preliminary Drainage Calculations DRAINAGE CALCULATIONS The following calculations were based on the requirements contained in the Drainage Design and Erosion Control Manual (DDECM) for Thurston County, 1994 Edition and the WSDOE Stormwater Management Manual, 1992 edition. DESIGN AND BASIN INFORMATION SUMMARY: Post Development Basin Area Summary (Acres) Sub-Basin A B Total Impervious Roadway 0.54 0.16 0.70 Concrete Sidewalk 0.06 0.02 0.08 Impervious Driveway 0.30 0.04 0.34 Impervious Roof Area 0.36 0.14 0.50 Disturbed Pervious 0.59 0.28 0.87 Total 1.85 0.64 2.49 Roof Area: 2,000 sf/lot Driveway Area: 600 sf/lot Soil Classification: SCS Soil Classification: Spanaway Gravelly Sandy Loam Hydrologic Group: A Design Infiltration Rate: Basin A - 15"/hr Basin B - 20"/hr BASIN `A' WATER QUALITY CALCULATIONS Minimum Stormwater Treatment Area Required: Formula 6-9 from page III-6-14: b = Qn - Zy 1.486 yi.ss~ so.s Qsmo = 0.24 cfs (see attached StormShed output) n = 0.07 Z=3 y=2"=0.1667' s = 0.02 b = 1.08' 1.08' x 200' long Swale = 217 sf min. Stormwater Treatment Area Provided: 217 sf / 2' wide =min. 109' long Total Treatment Area Provided 2' wide x 124' long = 248 sf > 217 sf .: OK Check Velocity: V=Q/A = 0.24 cfs /((2)(0.1667) +(3)(0.1667)2) = 0.58 cfs < 1.5 cfs .: OK BASIN `A' WATER QUANTITY CALCULATIONS *See attached StormShed software output Stage Elevation Live Storage Volume Pond Bottom Peak Stage* 1 ft Freeboard Total Storage Volume Provided 48 Hour Drawdown: 317.0 0 cf 318.0 1,209 cf 318.9 2,699 cf 319.0 2,879 cf 320.0 5,066 cf = 5,066 cf (992 sf)(15 in/hr)(1'/12")(48 hours) = 59,520 cf BASIN `B' WATER QUALITY CALCULATIONS Minimum Stormwater Treatment Area Required: StormShed software was used to model the runoff from a portion of the on-site roadway, sidewalks, and driveway areas. The 6-month storm event resulted in a peak volume of 842 cf. The DOE manual, section III-4.3.2, requires that "the permanent pool volume equals the runoff volume from the 6-month, 24-hour design storm. Therefore, using 85 LF of 4-foot diameter pipe as a wet vault, with across-sectional area of 10 sf at a 3-foot depth, results in an available pool volume of 850 cf, which exceeds the required volume of 842 cf. See the following StormShed modeling output. BASIN `B' WATER QUANTITY CALCULATIONS *See attached StormShed software output 30' long x 6' wide x 4.5' deep infiltration gallery with 3' dia. perf. pipe Void ratio = 0.30 [(30')(6')(4.5')- (30')(3.14)(3'^2)/4] (0.3) +(30')(3.14)(3'^2)/4 Total Storage Volume Provided = 391 cf Active Live Volume = 292 cf at Elev. = 321.3' per StormShed modeling 391 cf > 292 cf .: OK 48 Hour Drawdown: (30' x 6')(20 in/hr)(1'/12")(48 hours) = 14,400 cf > 292 cf .: OK ROOF RUNOFF Roof runoff from each residential home will be tightlined to individual lot infiltration drainrock drywells. The drywells shall be sized per Table 8.2 in the DDECM using a soil hydrologic Group "A" classification (125 cf per 1,000 sf of roof area). Olympic Engineering Crystal Springs Estates StormShed #05016 7/26/2005 Basin A Water Qualit Basin A 6-mo Event Summary: BasinlD Peak O Peak T Event ------- (cfs) (hrs) Basin A 6-mo 0.24 8.00 Drainage Area: Basin A 6-mo Hyd Method: SCS Unit Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area CN Pervious 0.0000 ac 77.00 Impervious 0.9000 ac 98.00 Total 0.9000 ac Supporting Data: Impervious CN Data: Roadway 98.00 Driveways 98.00 Sidewalks 98.00 Pervious TC Data: Flow type: Description: . Fixed None Entered Impervious TC Data: Flow type: Description: Shallow Impervious Peak Vol Area Method Raintype (ac-ft) ac /Loss 0.0793 0.90 SCS/SCS TYPE1A 6 mo Loss Method: SCS CN Number SCS Abs: 0.20 TC 0.00 hrs 0.06 hrs 0.5400 ac 0.3000 ac 0.0600 ac Length: Slope: Coeff: Travel Time 0.00 ft 0.00% 0.1000 0.10 min Length: Slope: Coeff: Travel Time 550.00 ft 1.00% 27.0000 3.40 min Basin A Water Quantity RLPCOMPUTE [Pond Level Pool] SUMMARY 100 yr MatchQ=PeakO= 1.0760 cfs Peak Out O: 0.3400 cfs -Peak Stg: 318.89 ft - Active Vol: 2699.78 cf Summary Report of all RLPooI Data Project Precips [2 yr] 2.00 in [5 yr] 2.50 in [10 yr] 3.00 in [25 yr] 3.00 in [100 yr] 4.00 in [6 mo] 1.28 in BASLIST2 [Basin A] Using [TYPE1A] As [100 yr] LSTEND BasinlD Peak Q Peak T Peak Vol Area Method Raintype Event ------- (cfs) (hrs) (ac-ft) ac /Loss Basin A 1.0760 8.00 0.3740 1.49 SCS/SCS TYPEIA 100 yr 1 of 5 Olympic Engineering Crystal Springs Estates StormShed #05016 7/26/2005 BASLIST [fYPE1A] AS [100 yr] DETAILED [Basin A] LSTEND Drainage Area: Basin A Hyd Method: SCS Unit Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 0.5900 ac 78.00 0.09 hrs Impervious 0.9000 ac 98.00 0.06 hrs Total 1.4900 ac Supporting Data: Pervious CN Data: Landscaping 78.00 0.5900 ac Impervious CN Data: Roadway 98.00 0.5400 ac Sidewalks 98.00 0.0600 ac Driveways 98.00 0.3000 ac Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Shallow Roadway 550.00 ft 1.00% 27.0000 3.40 min HYDLIST SUMMARY [Basin A 100-yr out] LSTEND HydID Peak Q Peak T Peak Vol Cont Area ------- (cfs) (hrs) (ac-ft) (ac) Basin A 100-yr out 0.34 7.75 0.3733 1.4900 STORLIST [Infiltration Pond] LSTEND Node ID: Infiltration Pond Desc: Infiltration Pond Start EI: 317.0000 ft Contrib Basin: Stage Input Volume 317.00 0.00 cf 0.00 cf 318.00 1209.00 cf 1209.00 cf 319.00 2879.00 cf 2879.00 cf 320.00 5066.00 cf 5066.00 cf Max EI: 320.0000 ft Contrib Hyd: Volume 0.0000 acft 0.0278 acft 0.0661 acft 0.1163 acft DISCHLIST [Infiltration Pond] LSTEND Control Structure ID: Infiltration Pond -Stage Discharge rating curve Descrip: Infiltration Pond Start EI Max EI Increment 317.0000 ft 320.0000 ft 0.10 Stage Discharge 2 of 5 Olympic Engineering Crystal Springs Estates StomtShed #05016 7/26/2005 317.0000 ft 318.0000 ft 319.0000 ft 320.0000 ft 0.0000 cfs 0.3400 cfs 0.3400 cfs 0.3400 cfs Basin B Water Quality Basin B 6-mo Event Summary: BasinlD Peak Q Peak T Peak Vol Area Method Event ------- (cfs) (hrs) (ac-ft) ac /Loss Basin B 6-mo 0.06 8.00 0.0193 0.22 SCS/SCS 8yz5~ Drainage Area: Basin B 6-mo Raintype TYPE1A 6 mo Hyd Method: SCS Unit Hyd Loss Method: SCS CN Number Peak Factor: 484.00 SCS Abs: 0.20 Storm Dur 24.00 hrs Area CN TC Pervious 0.0000 ac 77.00 0.01 hrs Impervious 0.2200 ac 98.00 0.04 hrs Total 0.2200 ac Supporting Data: Impervious CN Data: Roadway 98.00 0.1600 ac Sidewalks 98.00 0.0200 ac Driveways 98.00 0.0400 ac Pervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Fixed None Entered 0.00 ft 0.00% 0.5000 0.50 min Impervious TC Data: Flow type: Description: Length: Slope: Coeff: Travel Time Shallow Impervious 103.00 ft 5.00% 27.0000 0.28 min Channel Pipe 124.00 ft 0.18% 21.0000 2.32 min Basin B Water Quantity RLPCOMPUTE [Gallery Level Pool] SUMMARY 100 yr MatchQ=PeakQ= 0.3187 cfs Peak Out Q: 0.1961 cfs -Peak Stg: 321.38 ft - Active Vol: 292.31 cf Summary Report of all RLPooI Data Project Precips [2 yr] 2.00 in [5 yr] 2.50 in [10 yr] 3.00 in [25 yr] 3.00 in [100 yr] 4.00 in [6 mo] 1.28 in BASLIST2 [Basin B] Using [TYPE1A] As [100 yr] 3 of 5 Olympic Engineering Crystal Springs Estates StormShed #05016 7/26/2005 LSTEND Peak Vol Area (ac-ft) ac 0.1125 0.50 Method /Loss SCS/SCS Raintype BasinlD Peak Q Peak T Event ------- (cfs) (hrs) Basin B 0.3187 8.00 yr BASLIST [TYPE1A] AS [100 y r] DETAILED [Basin B] LSTEND Drainage Area: Basin B Hyd Method: SCS Unit Hyd Peak Factor: 484.00 Storm Dur 24.00 hrs Area CN Pervious 0.2800 ac 78.00 Impervious 0.2200 ac 98.00 Total 0.5000 ac Supporting Data: Pervious CN Data: Landscaping 78.00 Impervious CN Data: Roadway 98.00 Driveways 98.00 Sidewalks 98.00 Pervious TC Data: Flow type: Description: Sheet Landscaping Impervious TC Data: Flow type: Description: Shallow Impervious Channel Pipe HYDLIST SUMMARY [Basin B 100-yr out] LSTEND HydID Peak Q Peak T ------- (cfs) (hrs) Basin B 100-yr out 0.20 8.25 STORLIST [Infiltration Gallery] LSTEND Node ID: Infiltration Gallery Desc: Infiltration Gallery Start EI: 318.0000 ft Contrib Basin: Length Width 30.0000 ft 6.0000 ft DISCHLIST [Infiltration Gallery] TYPE1A 100 Loss Method: SCS CN Number SCS Abs: 0.20 TC 0.14 hrs 0.04 hrs 0.2800 ac 0.1600 ac 0.0400 ac 0.0200 ac Length: Slope: 96.00 ft 5.00% Length: Slope: 103.00 ft 5.00% 124.00 ft 0.18% Coeff: Travel Time 0.1500 8.31 min Coeff: Travel Time 27.0000 0.28 min 21.0000 2.32 min Peak Vol Cont Area (ac-ft) (ac) 0.1124 0.5000 Max EI: 322.5000 ft Contrib Hyd: Void Ratio 48.00 4of5 Olympic Engineering Crystal Springs Estates StormShed #05016 7/26/2005 LSTEND Control Structure ID: Infiltration Gallery -Infiltration control structure Descrip: Infiltration Gallery Start EI Max EI Increment 318.0000 ft 322.5000 ft 0.10 Infil: 20.00 in/hr Multiplier: 1.00 5of5 Appendix II Vicinity Map Q z Q ~d W ~ r L% ~ ~ w ~ c~ z Q ~o ~~ z ~ z U m ~ ~ j o Q 0 N W H Q a y a W N ~ Z f- pC Z y V J ~ ~ N V w X Z~ ao ~~ o~ ~ ~ J 01 l!'1 M N O ~ C Q O l A ~j ~S 1~ O ~ i0 ~ n 0 .n N M M N A u u .-1 0 Appendix III Drainage Basin Map ~ ~ ------- _ e .--~ --,~. - / ,.-o __ o - ~ I ~~Q m I i _ 1 i I I , ( N4 ' I I S R i I /My~ {.i.I / I R I I 31 = I ~I M ' ' / / I I I ( I ~.~- ,' ~ ~ o. I I ~ ~ ~ / ~ I I I N I I I n ~ I ~ I I I 3 sz« . I I I I I ~ ( ' I N °I I ~ ~ ~ I 1 1 ( ~ I N 'Q ~ I I I Z I 1 ~ " ~ ~ ' I Cl) o I d N ~ m ~ ~ I ,~ o ~ I -., o N ,gam ~ I I \\ ~ ~ ~ - o I o ~ I~ ~ I~ _ II p I °i I ° I I ~ ~ I ~ w J O i o I I I (n ~ o W U F- I I ~ I ~ O w ~ I I ~ ( O I ( I \I. I I I ~ U I \ I I v ~ a ~ I I i N ~ Z O ~ I a ~ L O al a ~ l X) 1 = I ~ . - I --Y~- - _ - wren ~ _s..w:m x _ _ _ _ - _ _ W ~ N W W w ~ a- ~co z~ z ~ z z m ~ ~ Q 0 m Q ? W a ~ mz W per, N Q J Z ~ Q N ~ ~ 0 ~ W X Z t0 w a O ti ti O ~ ~ ~ J 01 lA M N O ~ C Q OlA j ~i ~ o a~ is ao ~ p •n O O N E l0 t0 ~ ~. Appendix IV Soils Report SOIL EVALUATION REPORT FORM 1: GENERAL SITE INFORMATION PROJECT TITLE: Crystal Springs Estates SHEET: 1 OF 1 PROJECT NO. :05122 DATE: 6/14/05 PREPARED BY :William Parnell, P.E. 1. SITE ADDRESS: 1405 Crystal Springs Road SE, Yelm 98597 TAX PARCEL NUMBER: 22718330102, 22718330304 2. PROJECT DESCRIPTION: Create a 23 lot residential subdivision. 3. SITE DESCRIPTION: The 5.6 acre project site is currently occupied by a single residential dwelling, two barns and three smaller outbuildings. Site relief is rolling, rising from the east at Crystal Springs Road a distance of 150 feet lineal feet to the property's highest elevation of 332 ft. The site then slopes to the west approximately 140 lineal feet to a low point of 324 ft. Terrain then rises to the west a distance of 200 lineal feet to an elevation of 326 ft., then continues to slope away in a westerly direction to a low point of 309 ft. at Yelm Creek. Site distinguishing features include Yelm Creek as the western property line. Site vegetation consists of a small 2"d growth Fir tree grove_at the northeastern property corner, field grasses with isolated conifer and deciduous trees on the uplands, and thick indigenous brush and field grass ground cover bordering Yelm Creek on the lowlands. The project site is bounded to the east by Crystal Springs Road SE, developed residential property to the south and west and residential property to the north. On-site soils are a well-drained Spanaway series formed in glacial outwash. 4. SUMMARY OF SOILS WORK PERFORMED: Two test pits were excavated by backhoe to a maximum depth of 156" below existing grade. Soils were inspected by entering and visually logging each test pit to a depth of four feet. Soils beyond four feet were inspected by examining backhoe tailings. Two double ring infiltration tests were completed. Test pit soil log data sheets and infiltration test results are included in this report. 5. ADDITIONAL SOILS WORK RECOMMENDED: Additional soils work should not be necessary unless drainage infiltration facilities are located outside the general area encompassed by the soil test pits. 6. FINDINGS: The Natural Resource Conservation Service soil survey for Thurston County mapped the on- site soils as a Spanaway Gravelly Sandy Loam (110). Both test pits confirmed the Spanaway designation generally profiling a gravelly very fine sandy loam surtace soil overlying a very to extremely gravelly & cobbley coarse-fine sand substratum. The substratum gravels and sands were slightly loose. Winter water table was present in test pit #2 at 144" below the existing grade. No winter water table was present in test pit #1 and indicators were not visible. Double ring infiltration tests revealed an infiltration rate of 120 in/hr at 84" below the existing grade and 45 in/hr at 56" below the existing grade in test pit #1and #2 respectively. 7. RECOMMENDATIONS: The Spanaway soil series is a somewhat excessively drained soil that formed in gravelly glacial outwash. Infiltration rates are generally rapid in the substratum soils. The specified substratum C horizon soils should be targeted for all drainage infiltration facilities as noted in the attached soil log data sheets. A design infiltration rate of 20 in/hr would be appropriate for these targeted soils in test pit #1 and 15 in/hr or less in test pit #2. During construction, care must be taken to prevent the erosion of exposed soils. Drainage facility infiltration surfaces must be properly protected from contamination by the fine-grained upper horizon soils and from compaction by construction site activities. Soils not properly protected will cause drainage infiltration facilities to prematurely fail. I hereby certify that I prepared this report, and conducted or supervised the performance of related work. I certify that I am qualified to do this work. I represent my work to be complete an accurate within the bounds of uncertainty inh/e~rent to the prac ' of soils science, and to be suitable for its intended use. SIGNED: W ~. p DATE: C~// ~( oS of ~ Q ~~ ~ H N ~ °O ~O 9~ 2615 ~o ~~~ Q/STEP ~~? ~~~ONALEN (~'I~~CtS SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Crystal Springs Estates SHEET: 1 OF 2 PROJECT NO. :05122 DATE: 6/13/05 PREPARED BY :William Parnell, P.E. SOIL LOG: #1 LOCATION: 60 ft. west and 20 ft. south of the northeast property corner. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: Double Ring Infiltration Spanaway (110) Terrace 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: GROUP: Glacial Outwash A/B Unknown 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: Greater than bottom of hole Greater than bottom of hole Sloping 10. POTENTIAL FOR: EROSION RUNOFF PONDING Minimal Slow Minimal 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: A double ring infiltration test completed at 84" below the existing grade revealed an infiltration rate of 120 in/hr. Use a design infiltration rate of 20 in/hr or less for drainage infiltration facilities located in the C1, C2 and C3 horizon soils. Soils Strata Description Soil Log #1 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM ROO <X> FSP Ap 0"- 6" 10YR2/2 VCobSaLm <15 <5 <45 1 SBK - - - ff 2-6 2 Bw 6"- 10" 10YR3/6 VGrCSaLm <10 - <55 SG - - - ff 6-20 6 C1 10"- 48" 2.5Y3/2 GrCSa <1 - <35 SG - - - - >20 20 C2 48"- 90" 2.5Y4/2 VGrC-MSa <1 - <45 SG - - - - >20 20 few stones C3 90"-156" 2.5Y4/2 ExGrC-MSa <1 - <75 SG - - - - >20 20 some cobbles & stones SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Crystal Springs Estates SHEET: 2 OF 2 PROJECT NO. :05122 DATE: 6/13/05 PREPARED BY :William Parnell, P.E. SOIL LOG: #2 LOCATION: 630 ft. west and 200 ft. south of the northeast property comer. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: Double Ring Infiltration Spanaway (110) Terrace 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: GROUP: Glacial Outwash AIB Unknown 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: 144" Greater than bottom of hole Nearly Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Minimal Slow Minimal 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: A double ring infiltration test completed at 56" below the existing grade revealed an infiltration rate of 45 in/hr. Use a design infiltration rate of 15 in/hr or less for drainage infiltration facilities located in the C1 horizon soils. Soils Strata Description Horz Depth Color Texture A 0"- 30" 10YR2/1 VFiSaLm Bw 30"- 48" 10YR3/6 VGrLmC-FSa C1 48"- 66" 2.5Y4/2 ExGr&Cob C-FSa C2 66"- 92" 2.5Y4/2 ExGr&Cob C-MSa C3 92"-124" 2.SY5/2 Gravel & Cobbles with thick Clay binder C4 124"-156" 2.5Y4/2 Gravel & Cobbles with thin silt jackets Soil Log #2 %CL %ORG CF STR MOT IND CEM ROO <X> FSP <15 <5 <5 1 SBK - - - ff 2-6 2 10 - <40 SG - - - ff 6-20 6 <1 - <70 SG - - - - >20 20 <1 - <75 SG - - - - >20 20 <20 - <80 Mas - - - - - - <10 - <85 SG - - - - >20 20 Abbreviations Textural Class (Texture) Structure (STR) Grades of Structure Cobbley -Cob Granular - Gr Strong - 3 Stone - St Block - Blk Moderate - 2 Gravelly - Gr Platy - PI Weak - 1 Sandy - Sa Massive - Mas Loam - Lm Sin le Grained - SG Silty - Si Sub-Angular Blocky - SBK Clayey - CI Coarse - C Very - V Extreme) - Ex Fine - F Medium - M Induration 8~ Cementation (IND) (CEM) Weak - Wk Moderate -Mod Strong - Str Mottles (MOT) 1 Letter Abundance 1st Number Size 2nd Letter Contrast Few - F Fine - 1 Faint - F Common - C Medium - 2 Distinct - D Many - M Coarse - 3 Prominent - P Roots (ROO) 1st Letter Abundance 2nd Letter Size Few - f Fine - f Common - c Medium - m Man - m Coarse - c <X> -Generalized range of infiltration rates from SCS soil survey (<X>) DOUBLE RING INFILTRATION TEST CRYSTAL SPRINGS ESTATES Test Date :6/13/2005 Completed By : William Parnell, P.E. PE Job #05120 DOUBLE RING INFILTRATION TEST Test Hole # 1 (test run @ 84" be low existing gro und surface ) Start Sto Ela sed Time Total Dro Infiltration Rate ( Min) (Min) (Min) (Inches) (In/Hr ) 0 2' 00" 2' 00" 6 2' 00" 4' 15" 2' 15" 6 4' 15" 6' 30" 2' 15" 6 6' 30" 8' 30" 2' 00" 6 8' 30" 10' 45" 2' 15" 6 10' 45" 13' 00" 2' 15" 6 13' 00" 15' 15" 2' 15" 6 15' 15" 17' 45" 2' 30" 6 17' 45" 20' 15" 2' 30" 6 20' 15" 22' 45" 2' 30" 6 22' 45" 25' 45" 3' 00" 6 25' 45" 28' 45" 3' 00" 6 28' 45" 31' 45" 3' 00" 6 31' 45" 34' 45" 3' 00" 6 34' 45" 37' 45" 3' 00" 6 120 DOUBLE RING INFILTRATION TEST Test Hole # 2 (test run @ 56" below existing ground surface ) Start Sto Ela sed Time Total Dro Infiltration Rate ( Min) (Min) (Min) (Inches) (In/Hr ) 0 5' 45" 5' 45" 6 5' 45" 12' 30" 6' 45" 6 12' 30" 19' 45" 7' 15" 6 19' 45" 27' 30" 7' 45" 6 27' 30" 35' 30" 8' 00" 6 35' 30" 43' 30" 8' 00" 6 43' 30" 51' 30" 8' 00" 6 51' 30" 59' 30" 8' 00" 6 59' 30" 1:07' 30" 8' 00" 6 45