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HomeMy WebLinkAbout950801 ii" 1•O4- ORDINANCE NO. 9-F IN THE MATTER OF AN AMENDMENT TO THE WELD COUNTY INDIVIDUAL SEWAGE DISPOSAL SYSTEM REGULATIONS BE IT ORDAINED BY THE BOARD OF COUNTY COMMISSIONERS OF THE COUNTY OF WELD, STATE OF COLORADO: WHEREAS, the Board of County Commissioners of the County of Weld, State of Colorado, pursuant to Colorado statute and the Weld County Home Rule Charter, is vested with the authority of administering the affairs of Weld County, Colorado, and WHEREAS, pursuant to the Weld County Home Rule Charter the Board of County Commissioners acts as the Weld County Board of Health, and WHEREAS, C.R.S. Title 25, Article 10, Part 1 authorizes a Local Board of Health to adopt Individual Sewage Disposal System Regulations provided they are consistent with guidelines adopted by the Water Quality Control Commission at 5 C.C.R. 1003-6, and WHEREAS, the Water Quality Control Division has recently revised said guidelines, and WHEREAS, the Water Quality Control Division has, in the course of the revision, determined that the formula for computing the minimum area for an Evapotranspiration (ET) disposal system bed has been in error in the guidelines and, as a result, Weld County Ordinance 9, as amended, is in error and could lead to engineer-designed ET system beds being undersized by a factor of 2 1/2, and WHEREAS, the undersizing of ET beds may result in premature failure of ET systems and represents a threat to the quality of groundwater and to the health, safety and welfare of the residents of Weld County, and WHEREAS, an emergency exists as the continued failure to require proper size ET beds represents an ongoing threat to the public health, safety and welfare. NOW, THEREFORE, BE IT ORDAINED that Weld County Ordinance 9E, Section VI, is repealed and reenacted to read as follows : Section VI : Requirements for ET Systems 0RD #9-F 2407784 B-1460 P-579 09/22/94 04:28P PG 1 OF 6 REC DOC Mary Ann Feuerstein Weld Co. , Clerk & Recorder 0.00 950801 LAC ; //t.)PLy CA RE: ORDINANCE #9-F PAGE 2 6 . 1 Use. A. Evapotranspiration systems may be used where soil absorption of effluent is not possible and where high water table, bedrock, fractured rock, or highly pervious material precludes the use of a soil absorption system. B. An evapotranspiration system may be used exclusively or in combination with a soil absorption system. Combination systems are permitted where water table elevations or soil conditions permit leaching, but percolation rates may be satisfactory or acceptable. Calculations submitted for rates of effluent disposal shall include the leaching rate, the percolation rate and the evaporation rate. C. No new subdivision will be approved by the Division if greater than 25% of the subdivision' s septic systems are proposed to be evapotranspiration systems. 6 .2 Design Requir- ents A. An evapotranspiration system shall be designed by a registered professional engineer who shall furnish design data for a complete review of the design. B. Data to be furnished shall include, but shall not be limited to: liner material and bedding, properties of the soil in the evapotranspiration bed, and provision for vegetation cover. C. When high groundwater table, bedrock, fractured rock, or highly pervious material (percolation faster than 5 minutes per 1 inch) endanger the underground water, a durable and impermeable liner shall be installed to prevent the sewage effluent from entering the underlying formation or groundwater table. D. An evapotranspiration system shall be located in an area where there is exposure to sunshine. ORE) #9-F 2407784 8-1460 P-579 09/22/94 04:28P PG 2 OF 6 RE: ORDINANCE #9-F PAGE 3 E. The system bed shall be crowned and covered with a minimum of four (4) inches of selected backfill material and with a vegetation cover. F. Bed area shall be protected to prevent damage from vehicular or pedestrian travel . The ground surface shall be graded to deflect precipitation and other outside water away from the disposal area. G. The following formula may be used as a guide for determining the area necessary for total evapotranspiration of septic tank effluent : Area (square feet) = Design Flow (Gallons per day) X 586 Lake Evaporation at the Site (inches per year) H. As an alternative, a system may be designed on the basis of a monthly water balance for the system. Such a design would provide for total storage of average daily flows for all months in which the bed area is likely to be snow-covered or the ground at the site frozen. The design shall also provide wicks (sand structures which penetrate through the rock media to the bottom of the bed) equal to 10 to 15 percent of the bed surface area . The wicks shall be uniformly spaced throughout the bed. Adequate surface area shall be provided to evaporate/transpirate total annual average daily flows at a rate equivalent to local net lake evaporation over the remaining period of the year. (If the system is designed as a percolation/evapotranspiration system, the amount of storage and ET capacities may be reduced by the volume of effluent percolating into the soil . ) I . Sand utilized in Evapotranspiration or Evapotranspiration/Absorption beds for cover shall meet the following gradation requirements and be approved by the design engineer: oRL) #9-F 2407784 8-1460 P-579 09/22/94 04:28P PG 3 OF 6 RE: ORDINANCE #9-F PAGE 4 Sieve. Size Percent % Passing 4 100 40 <50-55% 200 <15 6 .3 Installation A. Septic tanks and aeration plants shall be level . The evapotranspiration bed bottom and any capillary interface shall be level within one (1) inch as measured from any perimeter, and shall be cleaned or smoothed of any sharp projections . A berm or drainage ditch shall be provided for a control of surface water drainage . B. The liner shall be sealed at all openings to the bed and shall completely underlay the matrix of the evapotranspiration bed. Seams shall be bonded tightly and imperviously. Any damage to the liner shall be repaired using the proper solvent or mastic and patch of the same material as the liner. Liners shall not be laid directly on any sharp rocks or objects . A sufficient amount of sand or dirt fill shall be added over sharp bedrock that will prevent the puncturing of the liner. Workmanship shall be of sufficient quality as to maintain the integrity of the liner to its specifications . A liner is required in high water table elevations, in jointed rock, or where leaching is prohibited. If the problem is solely due to excessive percolation rate, such rates may be retarded by soil building or replacement soil requirements as listed in 5 .4 C.4 of these regulations. C. The matrix shall be installed with care so that: the liner is not perforated. Heavy machinery shall not be permitted to drive over the matrix or the liner. The surface of the matrix shall be convex so as to permit run-off of rainwater and to increase the air turbulence over it . The surface of the matrix shall be provided with sod, or with grass cover, or with any other plants specified by the designer and shall be maintained as designed. The bed area shall be protected as to prevent vehicular, pedestrian, and livestock travel . 24O7784 R-1460 P-579 09/22/94 04:28P PG 4 OF 6 ORI) #9-F RE: ORDINANCE #9-F PAGE 5 BE IT FURTHER ORDAINED by the Board that no portion of this Ordinance shall be deemed to have given rise to a duty of care on the part of Weld County or its public employees, as defined at C.R.S. § 24- 10-103 (4) ,where none otherwise existed nor shall any portion of this Ordinance be deemed to constitute a Waiver of sovereign immunity by Weld County or its public employees. BE IT FURTHER ORDAINED by the Board, if any section, subsection, paragraph, sentence, clause, or phrase of this Ordinance is for any reason held or decided to be unconstitutional, such decision shall not affect the validity of the remaining portions hereof . The Board of County Commissioners hereby declarers that it would have enacted this Ordinance in each and every section, subsection, paragraph, sentence, clause, and phrase thereof irrespective of the fact that any one or more sections, subsections, paragraphs, sentences, clauses, or phrases might be declared to be unconstitutional or invalid. BE IT FURTHER ORDAINED that the effective date of this Ordinance shall be in accordance with Article III, Section 3-14 (6) of the Weld County Home Rule Charter but the design standards contained herein shall not be applied retroactively to any system for which a permit has been applied for or prior to August 31, 1994 unless that permit expires or has expired pursuant to Section 3 .7 of Ordinance 9-E, BE IT FURTHER ORDAINED by the Board that an emergency exits which requires that this Ordinance No. 9-F is declared to be an emergency ordinance under the provision of Section 3-14 (6) of the Weld County Home Rule Charter. 2407784 8-1460 P-579 09/22/94 04:28P PG 5 OF 6 ORD #9-F RE: ORDINANCE #9-F PAGE 6 The above and foregoing Ordinance Number 9-F was, on motion duly made and seconded, adopted by the following vote on the 14th day of September, A.D. , 1994 . A BOARD OF COUNTY COMMISSIONERS ATTEST:// WELD COUNTY, COLORADO Weld Co -e e Board b _ ) 11,0 (11( 1-,) t Ili-7-177 Ttail W. H. Webster, Chair an BY: r' , ^^. . Deputy L@r Co the Board Da e K. Hall, ro-T A AS TO FORM: / o- � � / ,- -:( _ /eo e E. Baxter eriCount tt'Sr y Co tance L. Harber. arbara J. Kirk eyer O Read and Approved: September 14, 1994 Published: September 22, 1994 Effective: September 14, 1994 2407784 B-1460 P-579 09/22/94 04:28P PG 6 OF 6 #9-F j ' a .. . ,f sn �. r eanus* a sus. t Oblearall ii*Baia' s M E:Eromt ":rr a AFFIDAVIT OF PUBLICATION Sat at MNttR mot me�nW MO STATE OF COLORADO A ss NONAi ant r �tabec o COUNTY OF WELD tiartri a a lidiieee IS M N: RageeeWe for Will- I, ROGER A. LIPKER, of said County of Weld, being duly va eta sworn,say that I am publisher of c___ a atrmaptr.11ari""an WINDSOR BEACON Conveys so MS0 used %loo .oa Wild eaeyeoantd of SS k not and , eawatM din a weekly newspaper having a general circulation in said al Oak w a en pervious met County and State, published in the town of WINDSOR, in ArMf tb,rani a th• U• at •s•s said County and State; and that the notice, of which the knit I iaddrfe.fn�t aillmaarmm annexed is a true copy, has been published in said weeky �°° M►aom aaaaen«+ for / successive weeks, that the notice was =it: F y+.. ~u�odatoob published in the regular and entire issued every number d o r I 1 m. the paper during the period and time of publication, and i i e s 0.C.R.Ue14, II w Pe' . the newspaper proper and not in a.supplement, and that auk the first publication of said notice was in said paper bearing Weft the ate d the / New witWeed the ce`vaa.aeaa r�w�yaae-� off( day d P��e�u-�o-r A.D., 19 9y and the swims,7ewoweueW n u rshall rata of last publication bearing the date of the Cordial (Wonist w arrr. "c INC the Rrnotaa.re day of AD., 19 and that for and w'Woman Mt the said WINDSOR BEACON has been published tro C.No nor,oubedasn rill 4 continuously find uninterruptedly for the period of 5 • t .... approved by nn x e•.. unnxsxno consecucve weeks, in said County and State, prior to the MW ^" � r'd' •i len% peptic warn a. date of brat publication of said notice, and the same is a is ot000loo to bea°aaarfa"dpf- newspaper within the meaning of an Act to regulate printing of legal notices and advertisements, approved May 18, • 1931,and all prior acts so far as in force. « ‘ t CA' CyB ISHER Subscribed and sworn to before me this,'" 7 day of • e,, z 1974! 4- 77 - 7/4-G-rn mo NOTARY PUBLIC My commission expires Qa, -F;-� / 'fie/6 . I —W Mt' -rr "47tit g n.�r r.lbw. rxc , lhat an war- � k ffjrynrmR ORDAINED n m +a I n '!'y7 k .. i 0µl r M ..ws.c. — r ryr'mr«m I wag,.? 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Ppb.a Alp• 1 MH pYYppYr,Cpalmar +74 I. 4 i "Mt N t a lsd F mn or mpn ppo-YMp,AlpMro- Ooh K.NpA,Pro Tarn r r: •. m M,.,�p.a�1tW.�__,...._.�_ds'llf S.. pre p 140.4 w.wwr.wa,�... doe,ar id *lap E. r appfAAieip .: : Ps 9 drAApAiptallY1 MAW xo prAiw Q p4l�rmwpal mLyal Caalpa4.H.rben MISL,s.s . !�! v4 auplipApt i.5nl RF iT.aRI a $wkra J.Kl arrays arT "'"�' R' la 1 all on � rim and Appro.R ����""� TAlospllApMI�AI iss as S ANS Ill, Aaphnbar la 1906 staligacans*****fa tat t 0*al Oat 9l; MA sal aaai'a Mader ant ID Ham. OS CII S Am hm4md:seaomppr 22 s1Na,#k . arlllp. *Wan HAp )x, ail.,, mEmoRAnDum ElkBard of County Commissioners Data September 8, 1994 COLORADO From Lee D. Morrison, Assistant Weld County Attorney Emergency Ordinance 9-F, Amendment to Individual Subject: Sewage Disposal System Regulations The State Health Department has recently determined that a factor in the formula used to determine the area of an evaporation bed in an evapotransporation (ET) system is in error in the state guidelines and has been that way for a number of years . The incorrect figure could result in ET beds being undersized by a factor of 2 ]l/2 times . The number of such systems in Weld County is a small percentage of the total number of systems but the Health Department and the County Attorney' s Office would recommend that the corrected formula be adopted as soon as possible to prevent any more of these systems being sized incorrectly. The proposed ordinance would provide that anyone who has applied for a permit as of August 31, 1994 would not be required to redesign their system provided that they did not let the permit lapse by failing to diligently pursue construction of the attached structure and the system. We request that this item be placed on the agenda for September 14 , 1994 . There will be a comprehensive review and revision of the septic regulations in the future to insure that Weld County' s regulations continue to remain consistent with the state guidelines with amendments to the Ordinance and this issue and any other policy could be addressed in more detail at that time. LDM/db: sewage Attachments Initial : Approve Schedule Recommendation Work Session Other Baxter Hall Harbert Kirkmeyer ✓/ Webster V pc: Health Dept. Weld County Atbrneyes Office . LDM • 8/30/94 317:16 Page 2 of 12 AUG-30-f994 06';27 P.01 ` COLORADO DEP & NT OF HEALTH (.l."igig---- Water Quality Control Division Ground Water & Standards Section y MEMORANDUM -- TO: State Board of He th p ` JUN 61994 FROM: Thomas Bennett • w. nrltLln , LfrT. DATE: June 1, 1994 SUBJECT: Sizing of Evapotranspiration Systems Accompanying this memorandum is a copy of the Water Quality Control Division's proposal for revision of the Individual Sewage Disposal System (ISDS) Guidelines with respect to evapotranspiration (ET) system sizing. The Division is proposing the inclusion of two methodologies for determining ET bed sizing. The first would correct the error contained in the Guidelines since the 1970's. That error involved a unit conversion factor of 237. The error was discovered as early as 1980, but it was never formally corrected to 586. The second alternative provides for a more custom sizing on the basis of a water balance. The system must be capable of storing liquid entering during periods when evaporation and transpiration is not occurring and of evaporating and transpiring liquid stored in the system and entering the system when those processes are taking place. Since the Board's hearing in April, staff has explored the appropriateness of its previous proposal as well as alternatives to that formula. Discussions have been held with a number of individuals both within and outside of Colorado with expertise in the field of ISDS design and regulation. The proposal to use the original formula with the conversion factor corrected to 586 is supported by EPA documentation and other research work. Discussions with other states shows a general dissatisfaction with methodologies presently in use and a high incidence of ET system failure. Some of these states experiencing high failure rates use or have used formulae similar to and more restrictive than that contained in the Guidelines. This lends further support to the need to correct this factor. In an effort to provide an alternative to the generic formula, which will increase systems by a factor of 2. 5, it is proposed that a water balance design basis be permitted as described above. This procedure is being used exclusively and successfully throughout New Mexico. RUG 30 ' 94 9115 L0M PRGE . 002 Weld County Attorney's Office LDM 8/30/94 91804 Page 3 al 12 AUG-30-1994 0EI:28 P.02 • STATEMENT 07 BASIS AND PURE SE The Individual Sewage Disposal System Guidelines were first adopted as temporary emergency Guidelines in October 1973 and, with minor revisions, were adopted by the State Board of Health in 1974. The Guidelines have undergone minor revisions numerous times over the years. One element of the Guidelines deals with systems utilizing evapotranspiration of wastewater effluent. The State's Individual Sewage Disposal Systems Act (Article 10 of Title 25) directs the establishment of minimum standards for individual sewage disposal systems including "Performance criteria and construction standards for evapotranspiration systems which dispose of effluent into the air by evaporation from a soil surface or transpiration of plants" (25-10-105(i) ) . Since the 1970's this element of the Guidelines has included a units conversion factor of 237 in the formula for evapotranspiration (ET) bed sizing. In 1980 the Division found this number to be in error and issued a memo indicating 586 to be the correct number. During the course of revisions to the Guidelines in 1984 and again in• 1988, this error was overlooked. Questions about ET system design and the basis for the number 237 recently caused knowledge of this error to resurface. The main objective of this revision is to correct a mathematical error in the formula for calculating the area of an evapotranspiration system. The revision also includes our alternative to use of the formula for designing ET systems. Such alternative incorporates a water balance in determining system size. The water balance addresses the basic concept of the ET system. The system must be able to store all flows during non- evaporative periods and evaporate all flows and storage during evaporative periods over the course of a year. This statement of basis and purpose applies only to that element of the current guidelines dealing with ET systems, and not to any former edition. The above statements are intended to comply with 24-2-103 (as amended) C:.R.S. , as prescribed by the statute. This revision to the Guidelines establishes basic standards for regulating evapotranspiration (ET) systems within the State of Colorado. These Guidelines are intended to comply with the legislative intent as stated in Title 25, Article 10, Section 102 C.R.S. XVII. Financial Impact Statement This revision will have a significant financial impact on those installing ET systems for their use if the standard formula is used. Correction of this error will increase RUG 30 ' 94 9 : 16 LDM PRGE . 003 Weld County Attorney's Office LDM 8/30/94 9:18:58 Page 4 of 12 AUG-30-1994 08:29 P.03 the cost of installing such a system by a factor of nearly 2.5. Those installing ET systems based on a water balance will likely see some increase in cost over design based on the present formula. This should be offset by a significant reduction in the rate of system failure. Most .. JA - --:.1. .. *hn r...,Ant inec nrnvi An AUG 30 ' 94 9: 16 LDM PAGE . 004 5. 9 Serial Distribution Systems A. Use: A serial distribution system may be used in all situations where a soil absorption system is permitted and shall be used where the ground slope does not allow for suitable installation of a single level absorption field. The horizontal distance from the side of the absorption system to the surface of the ground shall be adequate to prevent lateral flow and eruption of effluent above ground. B. Capacity: System capacity shall be ascertained using the same procedures outlined in 5.4 C. C. Construction: The bottom of each absorption trench and its distribution line shall be level. There shall be a minimum of twelve (12) inches of ground cover over the gravel fill in the absorption trenches. The absorption trenches shall follow approximately the ground surface contours so that variation in trench depth will be minimized. There shall be a minimum of six (6) feet of undisturbed earth between adjacent trenches and between the septic tank and the nearest trench. Adjacent trenches shall be connected with an overflow line or a drop box arrangement, in such a manner that each trench is completely filled with septic tank effluent to the full depth of the gravel before effluent can flow to the next trench downline. All other construction procedures for the serial distribution system are outlined in 5.5 A and B. D. Serial distribution systems shall meet the requirements of 5.5 C of these regulations. SECTION VI: REQUIREMENTS FOR EVAPOTRANSPIRATION SYSTEMS 6. 1 Use A. Evapotranspiration systems may be used where soil absorption of effluent is not possible and where high water table, bedrock, fractured rock, or highly pervious material precludes the use of a soil absorption system. B. An evapotranspiration system may be used exclusively or in combination with a soil absorption system. Combination systems are permitted where water table elevations or soil conditions permit leaching, but percolation rates may be satisfactory or acceptable. Partial or no liners may be permitted. Calculations submitted for rates of effluent disposal shall include the leaching rate, the percolation rate and the evaporation rate. C. No new subdivison will be approved by the Division if greater than 25% of the subdivision's septic systems are proposed to be evapotranspiration systems. 34 6.2 Material and Construction Requirements A. Septic tanks and aeration plants shall meet all of the requirements as provided for in these regulations. B. Liners shall be impervious to the chemical reaction and passage of sewage. Polyvinyl chloride plastic lining, manufactured from domestic polyvinyl chloride resin, of ten (10) mills thickness; butyl rubber, or other nontoxic equivalent materials, shall be used. C. Matrix material shall be resistant to chemical decomposition and the formation of colloidal particles. The matrix shall be well-graded and with the proper sizing to do the specified work of the design. The content of fine particles shall be limited to the extent that they do not inhibit capillary action or permeability. 6.3 Design Requirements A. All systems shall be designed by a Registered Professional Engineer who shall furnish design calculations to support the design and size of the system and shall inspect and approve construction of the system. Specifications to be furnished shall include, but not be limited to: liner material and protection of liner, soil analysis of select material, grain size, soil description and provision for vegetation cover. The Board of Health shall review and consider all evapotranspiration systems for approval. B. Designs shall provide for adequate depth (at least four (4) inches) of matrix and biological or external heat sources to prevent freezing. Septic systems shall provide at least two—compartment tanks for two or more units in series. Aeration plants shall be of sufficient capacity so that the matrix will not become impermeable during malfunctions. C. The following formula may be used as a minimum guide for determining the area necessary for total evapotranspiration of septic tank effluent: SIT Area = Flow (in gallons/day) X 237 (in sq. ft.) Lake evaporation rate at the site (in inches/year) 6.4 Installation A. Septic tanks and aeration plants shall be level. The evapotranspiration bed bottom and any capillary interface shall be level within one (1) inch as measured from any perimeter, and shall be cleaned or smoothed of any sharp projections. A berm or drainage ditch shall be provided for a control of surface water drainage. The bed shall be located in an open area, where there will be exposure to sunshine. 35 B. The liner shall be sealed at all openings to the bed and shall completely underlay the matrix of the evapotranspiration bed. Seams shall be bonded tightly and imperviously. Any damage to the liner shall be repaired using the proper solvent or mastic and patch of the same material as the liner. Liners shall not be laid directly on any sharp rocks or objects. A sufficient amount of sand or dirt fill shall be added over sharp bedrock that will prevent the puncturing of the liner. Workmanship shall be of sufficient quality as to maintain the integrity of the liner to its specifications. A liner is required in high water table elevations, in jointed rock, or where leaching is prohibited. If the problem is solely due to excessive percolation rate, such rates may be retarded by soil building or replacement soil requirements as listed in 5.4 C.4 of these regulations. C. The matrix shall be installed with care so that the liner is not perforated. Heavy machinery shall not be permitted to drive over the matrix or the liner. The surface of the matrix shall be convex so as to permit run—off of rainwater and to increase the air turbulence over it. The surface of the matrix shall he provided with sod, or with grass cover, or with any other plants specified by the designer and shall be maintained as designed. The bed area shall be protected as to prevent vehicular, pedestrian, and livestock travel. SECTION VII: REQUIREMENTS FOR ALTERNATE DISPOSAL SYSTEM 7. 1 Vaults Shall have a minimum 1,000 gallon effective capacity and may be permitted for indoor, water carriage sewage systems on property which cannot accommodate a sewage treatment system. Vaults shall meet the same installation and construction requirements as apply to septic tanks except chat no effluent outlet shall be provided. Vaults shall be provided with an indicator which signals when pumping is necessary. 7.2 Vault Privy Shall be constructed to include - a concrete fly and watertight receptacle; a superstructure affording complete privacy; an earth mound, around the top of the receptacle and below the floor level, which slopes downward away from the receptacle; a floor and riser of concrete or other impervious material; and a seat and lid of easily cleanable, impervious material, hinged, self-closing and fly proof. All venting shall be fly proofed with No. 16 or smaller mesh screening. The effective capacity of the privy receptacle shall be no less than 400 gallons. Metal or coated metal vaults are prohibited. 7.3 Chemical. Toilets Portable chemical toilets shall have a superstructure which meets the requirements of a vault privy and shall have a sewage receptacle of 36 Hello