Washakie County Planning Office 1001 Big Hom Avenue Suite 104 Worland~ Wyoming 82401 Office: (307) 347-6778 Fax: (307) 347-9366 E-mail: pjanner@washakiecounty.net 1- OkfWCJJ>d:ie Authorization to Construct a Small Wastewater Treatment Facility Application Washakie County reviews applications for and authorizes the construction ofsmall wastewater treatment facilities (septic tanks, single unit, domestic sewage) of less than 2,000 gallons pursuant to a delegation agreement between the Wyoming Department of Environmental QualityIWater Quality Division and Washakie County. You must contact WDEQIWQD at 510 Meadowview Drive, Lander, WY 82520 or call (307) 332-3144 for all other permits issued by that agency. Attached is a copy of the Washakie County application for authorization to construct, install, or modify small wastewater treatment facilities. If your design (The Washakie County Planning office does not design small wastewater treatment systems.) is approved, the Washakie County Planning Department will authorize you to construct an on-site treatment system according to the application you submitted. The authorization to construct your small wastewater treatment facility is not a warranty of the operation of the system. There are a number of different options for leach field design. Submit only the system detail sheet pertaining to the type of system you wish to build. You must designate a replacement area for the disposal field on the site plan sheet that must conform to the same requirements as the primary system in the event of the failure of the primary system. Please complete and submit the application form and the other forms contained in the packet appropriate to your particular application. A check in the full amount due is required at the time you submit your application to the Planning Office. Residential Septic Permit (new) $100.00 Residential Septic Permit (renewal) $ 50.00 The percolation test procedures along with general instructions are included in this packet. Be sure that at least three (3) percolation tests are run in the area and at the depth the proposed leach field will be located. You must also determine the depth to the highest seasonal groundwater by digging to at least eight (8) feet deep_ The bottom of the leach field must be at least four (4) feet above the highest seasonal groundwater level and four (4) feet above bedrock or impermeable soil. High groundwater may not be present when the pit is excavated. The planning staff or the professional installer can interpret the test pit to estimate high groundwater_ The Planning Office strongly encourages the use of professionals skilled at the installation of septic systems. You are also encouraged to contact the Planning Office with any questions you may have. Sincerely, Washakie County Planning Office
WASHAKIE COUNTY APPLICATION AUTHORIZATION TO CONSTRUCT, INSTALL, OR MODIFY SMALL WASTEWATER FACILITIES Please complete this application foffil in full, including pertinent attachments. The application must contain the original (for this office) and one (1) CODY (for your records) of each of the following: application foffil, pertinent design infoffilation sheets, plan sheets, and percolation test results. Submit the completed application form to the Washakie County Planning Office in the Washakie County Courthouse, 1001 Big Hom Avenue, Suite 107, Worland, WY 82401. 1. Name of Owner/Pemlitee: --------------------------------------------- Address: Telephone Number: 2. Name (and Company) ofinstaller Address: Telephone Number: 3. Location of facility. Township Range Section ~ Section 4. Type of Application. (Circle correct type) Ncw Replacement system As built 5. Briefly describe facilities proposed to be constructed and/or rcason for replaccment. This fonn must be signed by the owner, or in the case of the owner being a corporation or other business organization, by an individual with the legal authority to bind the corporation or business organization. I certity that to the best ofmy knowledge and understanding the application for Authorization to Construct, Install, or Modity Small Wastewater Facilities for the above described facility in Washakie County, Wyoming shall be constructed as authorized under the provisions ofany permit issued pursuantto W.S. 35-11-301(a)(iii) and (v) and other applicable State and County law. The signing ofthis application constitutes permission for a representative of the Washakie County Planning Office to enter onto the proposed facility site as needed for the purpose of inspection. Owner (Please print or type) Title Owner's Signature Date For Office use only: Application Number Date Permission Issued ------ Date Inspected By:
DESIGN INFORMATION PACKAGE SMALL WASTEWATER FACILITIES GENERAL INSTRUCTIONS for DESIGN: Less than 2000 Gallons Per Day GRA VITY SEPTIC SYSTEM utilizing a LEA CHFIELD Introduction - The following instructions are provided to assist you in submitting a properly completed application with design calculations and plan and detail sheets for a small wastewater treatment and disposal system (less than 2000 gallons per day). By carefully following the instructions and submitting all ofthe required information, delays can be avoided and a permit issued promptly. Disposal Field Alternatives The selection ofthe type ofdisposal system depends upon site conditions such as terrain, lot layout, soil percolation rates, seasonal high groundwater levels, and subsurface geology. The standard trench or bed type disposal system can be used under most conditions. At trench system tends to require less earthwork and leach field materials than a bed system. However, a bed system is more compact and may be desirable in situations where land area is limited. Trench or bed systems can be constructed with either perforated pipe and washed rock, or manufactured chambers. Ifthe site conditions are hilly such that the bottom ofthe disposal area eannot be kept level, then a side-hill type of disposal field may be desirable. A separate side-hill handout is available. Ifthe seasonal high groundwater level, bedrock, or an impervious clay layer is within four feet ofthe bottom of the proposed leach field, then a mounded, partially mounded, non-discharging pond, or evapotranspiration system may be required. Since these types offacilities are more difficult to design and construct, separate handouts have been prepared for each and are available upon request. A pumping system may sometimes be necessary to pump the sewage uphill from the house or septic tank to the leachfield. A separate handout is also available to assist you with this design. Application Submittal Requirements - A complete application package is necessary before a permit can be approved and issued. Only those pages used for your individual design need to be submitted. There may be several pages in the design package that do not apply to your system - these pages need not be included. Additionally, any pages marked as "Example" of "Instructions" can be omitted. As you go through the design package you previous page either has instructions or examples on it. The front side (right hand sheet) is the page that you actually fill out and submit. Design Information - The instructions and examples will help you to calculate the size ofyour wastewater system and to supply the information that is necessary for us to review your project. The design information should then be transferred to the appropriate detail sheets as needed for your system. The following abbreviations are used throughout the design package: gpd = gallons per day sfofsq ft = square feet mpl minutes per inch
DESIGN YOUR WASTEWATER TREATMENT SYSTEM Drinking water supplied by _--'-'-=.. GWlmd slope at location of leachfield 2=-- ft.ll OOft., or --:=. Soil Description -==;.L...==:..::.::... The seasonally high groundwater level is ---" feet below the ground surface. How was this determined? ---~==~~~~----------- The depth to bedrock or an impermeable layer is _--"- feet below ground surface. How was this determined? -----~==~~~---------- Septic tank size is,=..1o"-,,o~o gallons. lcompartment 2compartment Supplier? ~~~~~=~ Note: The minimum septic tank size required is 500 gallons for a 1 bedroom house, 1,000 gallons for a 2 4 bedroom house, 1,250 or 1,500 for a 5 or 6 bedroom house. X Leachfield size calculations S1. Design wastewater volume gpd = gallons per day Permanent structure: 150 gpdlbedroom x _3_bedrooms = _~4,-,,-5-,-0~pd or Mobile home: 1 or 2 bdrms = 350 gpd, 3 bdrms 500 gpd, 4 bdrms = 600 gpd or Shop building: 10 gpd/employee x employees gpd S2. The loading rate determined by the Percolation Test is "_-'-"- gpd/square foot S3. Calculate the minimum required intiltrative surface area: Wastewater volume (SI) ~- = _~~"-"-_ square feet Loading rate (S2) 0.46 gpd/sf EXAMPLE
DESIGN YOUR WASTEWATER TREATMENT SYSTEM Drinking water supplied by Ground slope at location of leachfield ft.l100ft., or Soil Description The seasonally high groundwater level is feet below the ground surface. How was this determined? -------------------- The depth to bedrock or an impermeable layer is feet below ground surface. How was this determined? -------------------- Septic tank size is gallons. 1compartment 2compartment Supplier? Note: The minimum septic tank size required is 500 gallons for a 1 bedroom house, 1,000 gallons for a 2-4 bedroom house, 1,250 or 1,500 for a 5 or 6 bedroom house. Leachfield size calculations SI. Design wastewater volume gpd gallons per day Permanent structure: 150 gpdlbedroom x bedrooms gpd or Mobile home: 1 or 2 bdrms 350 gpd, 3 bdrms 500 gpd, 4 bdrms = 600 gpd or Shop building: 10 gpd/employee x employees = gpd S2. The loading rate determined by the Percolation Test is " gpd/square foot S3. Calculate the minimum required infiltrative surface area: Wastewater volume (S1) gpd square feet Loading rate (S2) gpd/sf
EXAMPLE Type ofleach field system (Check one) Rock and perforated pipe trench Rock and perforated pipe bed Chamber trench system Chamber bed system Trench system with washed rock and perforated pipe calculations: (Distinct trenches with at least 3 feet of undisturbed soil between trenches) Dl. Depth below pipe (in inches)(6" minimum) inches)~ 112 = 4 square feet per linear foot Total linear feet of trench x 2 + width oftrench (in 83IDl = _-",,-~._linear feet (round up) 978.26/4 244.56 Bed system with washed rock and perforated pipe calculations: Width ~ ft. x Length _31_ ft. = _--'-~ Total square feet Total square feet must always be more than 83. Chamber system calculations: Manufacturer Infiltrator Model Quick4 Standard _---":.:..;,L:::.:;.;...;='-- Equivalent area per unit 26.5 (Trench) (See Chamber Systems Equivalent Area 22.5(Bed) sheet.) Note that the equivalent area per unit varies when using either a trench layout or a bed layout. Number of units needed: 831 Equivalent area per unit = 978.26126.5 36.9 978.26/22.5 = 43.5 44 (Bed) 37(French) units (round up)
Type ofleachfield system (Check one) Rock and perforated pipe trench...~ Chamber trench system Rock and perforated pipe bed Chamber bed system Trench system with washed rock and perforated pipe calculations: (Distinct trenches with at least 3 feet of undisturbed soil between trenches) Dl. Depth below pipe (in inches)(6" minimum) x 2 + width oftrench (in inches ) / 12 square feet per linear foot Total linear feet oftrench S31D1 = linear feet (round up) Bed system with washed rock and perforated pipe calculations: Width ft. x Length ft. =.. Total square feet Total square feet must always be more than S3. Chamber system calculations: Manufacturer ---------------- Model -------------- Equivalent area per unit (See Chamber Systems Equivalent Area sheet.) Note that the equivalent area per unit varies when using either a trench layout or a bed layout. Number ofunits needed: S3/ Equivalent area per unit = units (round up)
SI EXAI\1PLE PLAN '" Details that should be shown on a site plan: 1. The site plan shan show the location ofproperty lines, all buildings, all wens within 200 feet, septic tank, leachfield, water lines, streams and surface water bodies. 2. The septic tanks shall have the following minimum separation distances: a. 5 ft from any dwelling b. 10 ft from adjoining property lines c. 25 ft from potable water lines d. 50 ft from any water well e. 50 ft from any waterways 3. The leach-field shall have the following minimum separation distances: a loft from the septic tank b. loft from any building c. loft from adjoining property lines d. 25 ft from potable water lines e. 50 ft from any waterways North f. 100 ft from any water well U 4. An area sball be sbown on the site plan for future replacement oftbe leacbfield. Property line 12t.,.. j A I EXAMPLE NOT TO SCALE
SITEPLAN