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HomeMy WebLinkAbout3.0 Conditions of Approval6 SC HMU ES ER I GO RDO N I M EYER ENG I NEERS & SURVEYORS October 30 , 2000 Mr. Gary Aho 1588 Odin Drive Silt, Colorado 81652 RE : Dust-N-Sage Kennel Cistern Design Dear Gary, GLENWOOD SPRINGS I 18 W. 6TH, SUITE 200 G L ENWOOD SPR INGS , CO 8 I 60 I 970-945-I 004 FX : 970-945-5948 ASPEN P .O. BOX 2 I 55 ASPEN, C O 8 I 6 I 2 970-92 5-6727 F X : 970-925-4 I 5 7 At your request, and in order to meet a condition of approval for the Dust-N-Sage Kennel Special Use Permit, we are providing this letter to address the water system design for the kennel as it relates to water quantity and quality . In your application for the special use permit as well as for the supplemental information provided to the county, you note that the water demand for the kennel use is anti cipated to be 10-20 gallons per day. Additionally, subsequent conversations with you ha ve revealed that the system will be supplied by hauling water from local municipal sources where it is common place to sell potable water to individual users such as yourself. I understand that the hauled water will be stored in a 1000-gallon con crete storage vessel for use via a pumped delivery system for the kennel. Since imposing this condition for approval of the spe cial use permit , I ha ve had a phone conversation with Jeff Laurien , Senior Planner for the County Planning and Building Department. Mr. Laurien re-iterated that the county co mmissioners were concerned about the adequacy of th e design based upon the 20 gallon per day demand both from a quantity and quality standpoint. Of specific concern , I presume , is the large volume to demand ratio created by the use of the 1000- gallon storage vessel and the potential for the production of stagnant water. Therefore, I would like to take the remainder of this letter to address the County's concerns regarding water quantity and quality. WATER QUANTITY Given the 1000-gallon concrete c istern and the 20 gallon per day demand , the cistern volume has the capa c ity to provid e 50 days of average demand to the kennel and 12 to 13 days of continuous ma x imum day demands. Obviously, this represents a large volume and requires less need for frequent water hauling . If one were to "design " a syste m for the demands under "industry standards", a smaller storage volume would be required . For example, required storage typically considers the storage volume to be a combination of ma ximum day demands, emergen cy storage (equal to ma ximum day demands) and fire storage (when required). In your case, the max imum day demand , assuming an average day demand is 20 gallons per day , is 80 gallons per day. The emergency storage component is equal to the ma ximum day demand (80 gallons per day) as well. As your facility is lo cated in an existing subdi vision supp orted by fire flo ws (and storage) deemed adequate by the Burning Mountain Fire Protection District, no fire storage is required for you r fa cility. Therefore , the storage requirement at any point in time would be 160 gallons . Under average day demands, this would require you to haul water at a rate of every 3 to 4 days . Gi ven the previously mentioned "design volume ", we would re commend your schedule for hauling water cons ider a time period of every 10 to 20 days . This should accomm odate avoidance of 6 inclement weather for hauling water and should accommodate adequate storage for other factors such as kennel population, wash down's and other un-foreseen water demand occurrences. With this recommended schedule and average day demands, you should anticipate the need to haul anywhere from 200 to 400 gallons . This would repre se nt, assuming a 200-gallon tank is used , 1 to 2 trips every 10 to 20 days. Initially, we would recommend that you only provide 500 to 600 gallons of water in the cistern to establish the exact water use for the facility. This would provide the "required storage" plus the anticipated average day demand storage for the subsequent 10 to 20 day hauling cycle . By closely monitoring water use in the facility, the excess volume available will provide you an "equalization component" of storage in the cistern to accommodate a "regular hauling schedule ''. In summary, we anticipate that the 1000-gallon cistern will provide more than adequate storage for the facility . WATER QUALITY Given the 1000-gallon concrete cistern, water quality is of obvious concern. The major concerns are that of the water becoming stagnant and the potential growth of bacteria due to the potential high volume to demand ratio . The fact that your source of water is that of municipally treated potable water works in favor of maintaining water quality for the kennel. Your most likely source of water, I understand, will be from the Town of Silt. In fact, the Town's dispensing facility is close to their water treatment facility where the chlorine residual in the water is relatively high . Being a producer of potable water for municipal use, the Town is required to supply water with a chlorine residual at a rate that the residual will be maintained to trace levels at the most remote points in their distribution system . In fact, the State requires that the chlorine residual shall not be less than 2.0 mg/I at the immediate distal end of the water treatment plant. Being a surface water treatment plant , the Town of Silt is most likely maintaining 5.0 mg/I at the immediate distal end of their plant. Using the dispensing facility close to their water treatment facility will assure a so urce of adequately c hlorinated water with a high level of chlorine residual. In regards to water quality, we would recommend that the volume considerations outlined in the previous sections be followed . This would include not initially filling the cistern full, but half full . Also, th e hauling cycle of 10 to 20 days be followed and adjusted according to actual use, which is closely monitored. Assure that you use dispensing points in the municipal systems that are closest to the town 's water treatment plant. Finally , coordinate with Grand Junction Laborat ories to obta in chlorine residual test strips to allow you to continually monitor the presence of chlorine in the cistern . In the case that the chlorine residual becomes immeasurable, provide ch lorine tabl ets in the cistern to re -establish the chlorine residual to safe levels. Coordinate this pro ced ure with Grand Junction Laboratories or Schmueser Gordon Meyer, Inc. Hopefully, this letter respond s to the condition of approval for Garfield County. Upon your receipt and review, if you have any questions , please don 't he sita te to contact me. Resp ectfully Sub mitted : D:\work 'worddocs\october 30.doc (970 ) 94 5-1004 SGM ENGINEERS SURVEYORS 11..et:S RECEIV ED AUG 3 1 2000 FAX (9 70) 945 -5948 SCHMUESER ~~~~ GORDON MEYER 118 West 6th , Suite 200 Gle nwood Spri ngs , CO 81601 August 31 , 2000 Mr. Gary Aho 1588 Odin Drive Silt, Colorado 81652 RE: Dust-N-Sage Kennel Individual Sewage Disposal System Design Dear Gary, Per your request, SGM has evaluated the design of the proposed septic system to service the effluent from the proposed Dust-N -Sage Kennel to be located at 1588 Odin Drive, Silt, Colorado. This work is in response to the request made by the Garfield County Building and Planning Department during their review of your application of a special use permit for the aforementioned use. With this letter, you will find a number of attachments of wh ich are described as follows : 1. A photocopy of the Asgard Subdivision Plat, 3rd Filing , wherein the graphical description of your lot, Lot #37 is identified. Excepting a 30 foot drainage easement, no further easements are noted relative to the placement of the septic system on the 5.6593 acre parcel. 2. A photocopy of the Aho property identifying the existing improvements as well as the proposed optional sites for the proposed Kennel Bu ilding . 3. A photocopy of the Aho propoerty identifying the locations of the soil profi le holes and percolation holes . 4. A photocopy of the plans and elevat ions of the proposed building for the Dust-N - Sage Kennels . 5. A photocopy of the percolation test data compiled from the percolation/so ils testing performed on August 27, 2000. 6 . Design calculations for the individual sewage disposal system for the kennel. 7 . Table of setbacks for installation of individual sewage disposal system components . 8 . Detail of a "Standard Infiltrator Chamber''. 9 . Manufacturer's literature for the installation of the disposal field using infiltrator units. 10. Code information for the proper installation of the other various components of the septic system . Page 2 DESIGN FLOW DISCUSSION For the proper design of the individual sewage disposal system, it is necessary to determine the anticipated design flows intended to utilize the system on a daily basis. Based upon our discussions, it appears that the special use permit has considered the population of the kennel to potentially house twenty (20) dogs. Our review of the building construction plans indicates that the kennel will actually provide individual kennel packages (ie., wire cages) for one-half of that population, or ten (10) dogs. However, from the county review standpoint, since the application is for up to 20 dogs, we will address the "worst case" scenario which considers the 20 dogs. If, during further planning, and upon the submittal of a "septic permit" concurrently with the building permit it is determined that the system will only need to accommodate ten (10) dogs, then the system can accordingly be down sized. Because this system will be an additional system housed on the 5.6593 acre parcel, the county is concerned with the combined flow for the lot not serving over 2000 gallons per day, average daily flow. Therefore the entire flow for the site is also calculated. For the kennel itself please note the following: 1. Design for 20 dog population. 2. From Table I, "Quantities and BOD Strength of Sewage for Various Types of Uses' of the 1994 Edition of the "Individual Sewage Disposal Systems" design guidelines of the Colorado Department of Health, Water Quality Control Division, the average daily flow, per dog, for kennels is thirty (30) gallons per day. 3. Average Daily Flow for Dust-N-Sage kennel is: 20 dogs X 30 gallons per day per dog = 600 gallons per day (gpd) For the existing home (three (3) bedroom home), please note the following: 1. Three bedrooms in home. 2. Two persons per bedroom. 3. Seventy five (75) gallons per day per person. 3 bedrooms X 2 persons per bedroom X 7 5 gallons per person per day = 450 gallons per day (gpd) Total flow for the site is: Kennel: 600 gpd Home: 450 gpd Total: 1050 gpd Note that since the total flow from the site is less than 2000 gallons per day, the county will be able to process the permitting for the individual sewage disposal system. ~---------------SCHMUESER GORDON MEYER, INC·----------------' Page 3 PERCOLATION TESTING The soil profile hole excavated for the site did not encounter the presence of either bedrock nor ground water in existence within 8 feet of the surface. Additionally, the percolation testing indicated a "worst case" percolation rate of 40.33 minutes per inch. Given the observations of the soil profile hole as well as the results of the percolation tests, a standard ISDS design can be performed using the guidelines outlined in the county's ISDS regulations. COMPONENT SIZING The septic tank size for the 600 gpd average daily flow will need to have a nominal capacity of 1, 125 gallons considering the 1.5 peaking factor to derive the design flow and the 30 hour required detention time. The absorption area tor the disposal field will need to be 1, 143.11 square feet considering the design flow (average daily flow times 1.5) and the 40.33 minute per inch percolation rate. As was previously mentioned, we have attached the manufacturer literature for the utilization of infiltrator chambers for the disposal field construction. Please note that if this product is used, the State Health Department as well as Garfield County recognizes a reduction of absorption area requirement by 30% for use of the infiltrators in a "bed configuration" and 50% for use of the infiltrators in a "trench configuration". Typically, site and setback constraints determine the most feasible configuration for the disposal field construction. However, it appears that neither of these constraints are applicable and that the configuration can be economically selected by yourself or your contractor. SUMMARY Based upon the information attached, it appears that the provision of Iha septic system on this site is feasible for even the worst case scenario when considering dog population. Flexibility in selecting the type of disposal field is also available. Please note that as you further decide upon final dog population for design and absorption field construction, we can be of further assistance to prepare specific plans for construction. However, an experienced installer of septic systems within Garfield County, whom is also knowledgeable with the county's ISDS regulations will be able to properly provide the construction of the system without further information. Assistance will also be given to you from the county's inspector upon submittal of an application for a "septic system permit' as well as through inspections during construction of the system itself. I appreciate you having given SGM the opportunity to be of service to you in this matter. If you have any questions or need further assistance, please don't hesitate to call. ~---------------SCHMUESER GORDON MEYER, INC·---------------~