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HomeMy WebLinkAbout3.0 Correspondence & ConditionsGlenn Hartmann From: Michael Erion <merion@resource-eng.com> Sent: Monday, October 03, 2016 9:48 AM To: Glenn Hartmann Subject: RE: Chavez Site Response Glenn: I reviewed the most recent response materials received September 28, 2016 including a 9/27/2016 response letter, an updated report (9/27/2016), and updated foundation and grading plans (9/20/2016). The new submittal addresses RESOURCE's concerns outlined in our June 17, 2016 review letter. The elevation certificate will be submitted by the surveyor after construction is complete. Regards, Michael Michael Erion, P.E. Water Resources Engineer (970) 945-6777 Voice (970) 945-1137 Facsimile www.resource-eng.com The information contained in this e-mail is PRIVILEGED AND CONFIDENTIAL information intended only for the use of the individual or entity named above. If the reader of this message is not the intended recipient, or the employee or agent responsible to deliver it to the intended recipient, you are hereby notified that dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify us by telephone and delete the original message from your system. Thank You. From: Glenn Hartmann [mailto:ghartmann@garfield-county.com] Sent: Monday, October 03, 2016 9:11 AM To: Michael Erion <merion@resource-eng.com> Subject: FW: Chavez Site Response Hi Michael: I've taken a look through the new material and it looks like he has addressed the conditions and your referral comments. If you have a chance to talk today to confirm that they have meet your concerns that would be great. I'm pretty available. Thanks. Glenn Glenn Hartmann, Senior Planner Garfield County Community Development 970-945-1377 x1570 ghartmann@garfield-county.com From: Glenn Hartmann Sent: Wednesday, September 28, 2016 3:31 PM To: 'Michael Erion' <merion@resource-eng.com> Subject: FW: Chavez Site Response Hi Michael: Here is the latest from Civco. Thanks. Glenn. 1 Glenn Hartmann, Senior Planner Garfield County Community Development 970-945-1377 x1570 ghartmann@garfield-county.com From: John Barrus [mailto:johnbarrus@civcoengineering.com] Sent: Wednesday, September 28, 2016 2:59 PM To: Glenn Hartmann<ghartmann@garfield-county.corn> Subject: Chavez Site Response Glenn, Per our conversation this afternoon, I have revised the Site Plan and Comment Response letter. The documents are attached in the following link. ShareFile Attachments Title Size Chavez Comment Response.pdf 152.6 KB Chavez Floodplain Report Revi .pdf 243.6 KB Chavez-Site_Plan-Revl .pdf 403 KB John Barrus uses ShareFile to share documents securely. Learn More. Thanks, John B. Barrus, PE CIVCO Engineering, Inc. PO Box 1758 1256 West 400 South Vernal, Utah 84078 (435)789-5448 — Office (435)790-8610 — Cell (435)789-4485 — Fax email: johnbarrus@civcoengineering.com 2 Glenn Hartmann From: John Barrus <johnbarrus@civcoengineering.com> Sent: Tuesday, September 20, 2016 3:49 PM To: Glenn Hartmann Subject: Chavez Residence Glen, I have a question about the following comments from your review: 3. The plans indicate a crawl space for the foundation system. The Applicant should address location, elevation and size of openings and address compliance with enclosure openings if appropriate. Specifically. the east side of the structure foundation could be subject to flooding in the crawl space. d. Specific plans for crawl space openings including size and location demonstrating compliance with FEMA requirements. Do you want a flow through foundation, or just for us to provide an opening for water to exit the crawlspace if it floods? Should the plans be part of the structural foundation plans? Thanks, John B. Barrus, PE CIVCO Engineering, Inc. PO Box 1758 1256 West 400 South Vernal, Utah 84078 (435)789-5448 — Office (435)790-8610 — Cell (435)789-4485 — Fax email: johnbarrus@civcoengineering.com 1 (pir' CIVCO Engineering, Inc. Vernal, Utah CIVCO Engineering, Inc. Civil Engineering Consultants PO Box 1758 * 1256 W 400 5, Suite 1 Vernal, Utah 84078 May 4, 2016 Amended September 27, 2016 RE: CMH Flood Plain Development Permit (File No. FDPA-04-16-8445) 1.0 Summary The Chavez residence will be located on Lots 8 & 9 Rifle Village South; on Remington Ave. in Garfield County. This property is situated within a Zone AO Special Flood Hazard Area (SFHA) subject to inundation by the 1% annual chance flood. Zone AO is defined as "Flood depths of 1 to 3 feet (usually sheet flow on sloping terrain); average depths determined. For areas of alluvial fan flooding, velocities also determined." The flood zone is associated with alluvial fan flooding from Helmer Gulch, and the 100 year discharge is defined as 760 cubic feet per second (cfs). The flood depth in this area is defined as 1 foot with a velocity of 4 feet per second (fps). The entire parcel is located within the flood zone. The proposed residence will be a single story manufactured home with treated lumber framed perimeter foundation walls on concrete footings and chassis supports on spot footings throughout the crawl space. The structure will be anchored to resist flotation using tie straps on the chassis frame anchored to the exterior foundation. The finished floor elevation (FFE) will be 2 feet higher (5365.37) than the highest adjacent ground elevation (5363.37). The lot will be graded to provide positive drainage away from the structure in all directions. 2.0 County Floodplain Overlay Regulations The Garfield County Land Use and Development Code specifies general standards for development within a floodplain and specific standards that apply to the different types of SFHA zones that have been defined. The sections of that code that apply to the proposed project are 3- 301 B -G, 4-109, and 4-203. These sections are discussed in sections 2.1, 2.2 and 2.3 of this report. 2.1 Garfield County Land Use and Development Code 3-301 3-301 B. General Standards. In the Floodplain Overlay, the following provisions are required for all New Construction and Substantial Improvements: 1. All New Construction or Substantial Improvements shall be designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. Phone (435)789-5448 * Fax (435)789-4485 Email: civco@civcoengineering.com The proposed residence will be a single story manufactured home with treated lumber framed perimeter foundation walls on concrete footings and chassis supports on spot footings throughout the crawl space. The structure will be anchored to resist flotation and lateral movement using tie straps on the chassis frame anchored to the exterior concrete foundation. Refer to attached foundation plans. 2. All New Construction or Substantial Improvements shall be constructed by methods and practices that minimize flood damage. The proposed project site has been designed to minimize the probability for floodwaters to impact the proposed structure. Refer to sections 4.0 Site Grading and 5.0 Flood Damage Protection. Construction materials have been specified according to the International Residential Code Section R401. Refer to attached foundation plan. 3. All New Construction or Substantial Improvements shall he constructed with materials resistant to flood damage. Foundation materials have been specified per the International Residential Code Section R401. Refer to section 4 Site Grading and to the attached foundation plan. 4. All New Construction or Substantial Improvements shall be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment, and other service facilities that are designed and/or located so as to prevent water from entering into or accumulating within the components during conditions offlooding. The finished floor elevation of the structure will be 5365.37 feet which is 1 foot higher than the reported flood water depth. A concrete slab for the air conditioning unit will be constructed with a finished top of slab elevation of 5364.37 feet. All electrical, heating, ventilation, plumbing, and air conditioning equipment, and other service facilities have been designed to keep those systems higher than the 100 -year floodwater elevation. Refer to section 5.0 Flood Damage Protection. S. All Manufactured Homes shall be installed using methods and practices which minimize flood damage. For the purposes of this requirement, Manufactured Homes must be elevated and anchored to resist floatation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over -the -top or frame ties to ground anchors. This requirement is in addition to applicable State and local anchoring requirements for resisting wind forces. The structure will be anchored to resist flotation and lateral movement using tie straps on the chassis frame anchored to the exterior concrete foundation. The foundation has been designed according to the International Residential Code section R401. Refer to section 5.0 Flood Damage Protection and to the attached foundation plans. Page 1 2 6. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration offlood waters into the system. The proposed project will connect to the Rifle City culinary water system. The water service lateral will be water tight and will terminate above the finished floor. 7. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration offlood waters into the system and discharge from the systems into flood waters. The proposed project will connect to the Rifle City sanitary sewer system. The sewer service lateral will be water tight and will terminate at or above the finished floor. 8. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding. Does not apply. There is no on-site waste disposal system. 3-301 C. Specific Standards. In the Floodplain Overlay, where BFE data has been provided. Does not apply. Base flood elevation has not been provided on FIRM. 3-301 D. Floodway. The proposed structure is not located within the floodway. The floodway will not be altered in any way by this project. Refer to attached FIRM. 3-301 E. Standards for Areas of Shallow Flooding. Areas designated as shallow flooding are located within the SFHAs. These areas have special flood hazards associated with Base Flood depths of 1 to 3 feet where a clearly defined channel does not exist and where the path offlooding is unpredictable and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply: 1. All New Construction and Substantial Improvements of residential structures have the Lowest Floor (including Basement) elevated above the highest adjacent Natural Grade at least 1 foot above the depth number specified in feet on the community's FIRM (at least 3 feet if no depth number is specified). The high point of the lot around the perimeter of the proposed structure has an elevation of 5363.37 feet and is located at the south east corner of the proposed structure. The finished floor elevation of the structure will be 5365.37 feet which is lfoot higher than the reported flood water depth of 1 foot. Page 1 3 2. All New Construction and Substantial Improvements of nonresidential structures: Does not apply. This is a residential structure. 3. Adequate drainage paths around structures are required to guide flood waters around and away from proposed structures. Drainage shall not adversely impact adjacent properties. The lot will be graded to provide positive drainage away from the structure in all directions. The existing site is crowned and approximately one quarter of the lot drains northerly toward Remington Avenue. The remaining three quarters of the lot drains to the alley on the northern side of the lot. Proposed site grading will maintain the same general grading pattern. Refer to section 4.0 Site Grading and the grading and drainage plan attached to this document. 3-301 F. Properties Removed from the Floodplain by Fill. Does not apply. 3-301 G. Alteration of a Watercourse. Does not apply. 2.2 Garfield County Land Use and Development Code 4-109 4-109. DEVELOPMENT IN THE 100 -YEAR FLOODPLAIN. 4-109A. Overview. Applications for development within the 100 year Floodplain must receive a Floodplain Development Permit prior to any development. A floodplain development permit has been applied for. 4-109B. Review Process. Development in the 100 -Year Floodplain shall be processed pursuant to section 4-103, Administrative Review. A Floodplain Development Permit shall be issued upon approval of the application. Pending review by county. 4-109C. Review Criteria. A Floodplain Development Permit may be issued by the Director or designated Floodplain Administrator if it is found that the application is in conformance with section 3-301, Floodplain Overlay Regulations, and upon weighing the following relevant factors: 1. The danger to life and property due to flooding or erosion damage; Refer to section 3.0 Flood Plain Analysis. Page 1 4 2. The susceptibility of the proposed facility and its contents' to flood damage and the effect of such damage on the individual owner; Refer to sections 3.0 Flood Plain Analysis, 4.0 Site Grading and 5.0 Flood Damage Protection and the attached site plan drawings. 3. The danger that materials may be swept onto other lands to the injury of others; Refer to sections 3.0 Flood Plain Analysis, 4.0 Site Grading and 5.0 Flood Damage Protection and the attached site plan drawings. 4. The compatibility of the proposed use with existing and anticipated development; The proposed single family dwelling is located within a residential subdivision. 5. The safety of access to the property in times of flood for ordinary and emergency vehicles; The proposed project will have no effect on the safety of access to the property by ordinary or emergency vehicles. 6. The costs of providing governmental services during and after flood conditions, including maintenance and repair of streets and bridges, and public utilities and facilities such as sewer, gas, electrical, and water systems; The proposed project will not increase the costs of providing governmental services during and after flood conditions. 7. The expected heights, velocity, duration, rate of rise, and sediment transport of the flood waters and the effects of wave action, if applicable, expected at the site; Refer to section 3.0 Flood Plain Analysis. 8. The necessity to the facility of a waterfront location, where applicable; Does not apply. 9. The availability of alternative locations, not subject to flooding or erosion damage, for the proposed use; Does not apply. 10. The relationship of the proposed use to the Comprehensive Plan for that area. The proposed single family dwelling is located within a residential subdivision. Page 1 5 2.3 Garfield County Land Use and Development Code 4-203 4-203 0. Floodplain Analysis. When a project is located within a Special Flood Hazard Area, if there is an indication or suggestion that a project is located in a SFHA, or if a project is a division of land or a PUD over 5 acres in size or proposes 50 lots or greater, the application must include a Floodplain Analysis. 1. Floodplain Specific Site Plan. The Applicant shall submit a Site Plan with specific • information pertaining to the SFHA and shall include the following elements. The Floodplain Administrator may require, or the Applicant may choose to submit, a more detailed version of all or part of the Site Plan. Any elevation information shall be provided in the North American Vertical Datum of 1988. a. Base Flood boundary and water surface elevations; Refer to attached FIRM. b. Floodway boundary; Refer to attached FIRM. c. Channel of water course; Refer to attached FIRM. d Existing and proposed topographic contours shown at vertical intervals of no greater than 2 feet; Refer to the attached site plan drawings. e. Elevation of the Lowest Floor, including Basement and garage, or each existing and proposed structure; Refer to the attached site plan drawings. f Proposed elevations to which structures will be flood -proofed; Refer to the attached site plan drawings. g. Existing and proposed location, dimension, and elevation of proposed landscape alterations, structures, streets, water supply and any sanitation facilities; Refer to the attached site plan drawings. Page 1 6 h. Boundaries and total land area of existing and proposed impervious surfaces, including structures; and Refer to the attached site plan drawings. i. Location of existing water supply ditches, irrigation ditches and laterals. Refer to the attached site plan drawings. 2. A certificate from a qualified professional engineer or architect that the nonresidential flood proofed structure shall meet the flood proofing criteria in section 3-301.C.2., Specific Standards for Nonresidential Construction. Does not apply. This is a residential structure. 3. An elevation certificate from a qualified professional surveyor, engineer or architect that certifies that all residential construction and mechanical equipment will be at least 1 foot above BFE. Refer to the attached elevation certificate, prepared by Kipp Land Surveying. 4. Description of the extent to which any watercourse or natural drainage will be altered or relocated as a result of proposed development. No watercourse or natural drainage will be altered or relocated as a result of the proposed development. Refer to the attached grading and drainage plan and FIRM. 5. An engineer's report completed by a qualified professional engineer experienced in hydrology or hydraulics, using a methodology acceptable to FEMA or the CWCB, that address the standards in section 3 -301.B -G. of this Code. This report has been prepared to specifically address the requirements of the Garfield County Land Use and Development Code 3 -301.B -G and standard level of care for development within an SFHA. 3.0 Flood Plain Analysis The Zone AO SFHA is an alluvial fan shallow flood plain. In an alluvial flood plain, the entire plain is not inundated during every flood event. An alluvial flood plain is formed over thousands of years. High velocity, sediment laden flood waters enter the flatter flood plain and gradually slow until the waters no longer have the energy required to transport the sediment they contain. When the waters slow sufficiently, the sediment settles out of the water creating deposits on the flood plain. As this process occurs over many years the alluvial fan changes shape topographically and flow paths are changed for each succeeding flood event. Page 1 7 The 100 year flood discharge at the mouth of Helmer Gulch is 760 cfs with a flood depth defined at a depth of 1 foot with a velocity of 4 fps. The width of the flood plain at the project, scaled from the firm map, is approximately 3500 feet. Using the continuity equation (Q = vA) we can solve for the width of flow of the 100 year flood, which will be approximately 190 feet. From this, in the event of a 100 year flood (0.1 % chance) the percent chance for this property to be inundated is approximately 5% (190ft/3500ft). Other factors influencing flooding in this area include roads, grading due to land development and farming activities and the development of Helmer Gulch itself. The alluvial fan has been developed significantly over the past 40 years. The roads in the Rifle Village South Subdivision alone will do much to channelize and potentially split the flow of flood waters through this area. This report does not include the analysis of these impacts, but merely mentions them to show that by following the standards specified in the Garfield County Land Use and Development Code, the proposed residence will be reasonably protected from damage caused by flooding. A flood plain report prepared by Jerome Gamba & Associates in May of 1996 was referenced in the preparation of this report. A copy of that report has been attached to this document. 4.0 Site Grading The project site is currently vacant. Remington Avenue drains generally from east to west. The existing site is crowned and approximately one quarter of the lot drains northerly toward Remington Avenue. The remaining three quarters of the lot drains to the alley on the northern side of the lot. Proposed site grading will maintain the same general grading pattern. The high point of the lot around the perimeter of the proposed structure has an elevation of 5363.37 feet and is located at the south east corner of the proposed structure. The finished floor elevation of the structure will be 5365.37 feet which is lfoot higher than the reported flood water depth of 1 foot. Finished grade elevations around the structure will be 18 inches below the FFE or 6 inches above the existing grade. A concrete slab for the air conditioning unit will be constructed with a finished top of slab elevation of 5364.37 feet. The lot will be graded to provide positive drainage away from the structure in all directions. Refer to the grading and drainage plan attached to this document. 5.0 Flood Damage Protection The proposed project will connect to the Rifle City culinary water and sanitary sewer systems. Service laterals will be water tight and will terminate at or above the finished floor, thereby minimizing or eliminating the infiltration of potential flood waters into either system. To protect the proposed structure from flotation, collapse or lateral movement, the structure will be anchored using tie straps on the chassis frame anchored to the exterior concrete foundation at regular intervals along the north and south sides. Openings in the foundation wall have been designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood waters. Openings have been Page 18 designed using guidance found in FEMA Technical Bulletin 1-08 Openings in Foundation Walls and Walls of Enclosures. Refer to foundation plan. 6.0 Conclusion The proposed project has been designed with flood protection in mind. The Garfield County Land Use and Development Code and FEMA Technical Bulletin 1-08 have been used as for guidance in the selection of measures used to protect the proposed structure from flood damage. By constructing the site according to the proposed site plan and the Development Code, and following FEMA guidelines, the home will be reasonably protected from damage caused by flooding. Pre ed by: 6—(A44-1. Jhn B. Barrus Approved by: Vance V. King, P.E. Page ( 9 CIVCO Engineering, Inc. Vernal, Utah CIVCO Engineering, Inc. Civil Engineering Consultants PO Box 1758 * 1256 W 400 5, Suite 1 Vernal, Utah 84078 September 27, 2016 RE: Resource Engineering Inc. Comment letter and Staff Report, both dated August 16, 2016 Resource Comment 1 The anchoring system is listed as an over the top tie down in the CIVCO report, but the design drawings show a foundation system with tie straps to the floor joists. Both systems are acceptable, but the Applicant should clarify the design so that the floodplain permit and building permit are consistent for the project. Response The text of the flood plain report has been revised to say "the structure will be anchored using tie straps on the chassis frame anchored to the exterior concrete foundation". Resource Comment 2 The grading plan on Sheet 2 of the CIVCO drawings calls out a high point on the west fence line with half the drainage flowing north and half flowing to the south. The existing topography does not appear to support this label. RESOURCE agrees with this approach so as to not impact the property to the west. It is recommended that the drawings indicate specific elevations at the high point and at the northwest and southwest corners for the contractor to provide the intended drainage concept. Response The grading plan has been revised to include the spot elevations at the high point and the corners of the lot. Resource Comment 3 The plans indicate a crawl space for the foundation system. The Applicant should address location, elevation and size of openings and address compliance with enclosure openings if appropriate. Specifically, the east side of the structure foundation could be subject to flooding in the crawl space. Response The foundation plan has been revised to show the flood openings. Phone (435)789-5448 * Fax (435)789-4485 Email: civco@civcoengineering.com Staff Comment 4 a Confirmation that all utility connections are designed and protected from infiltration by flood waters and confirmation that all utility facilities and equipment such as air conditioning units will be elevated at least one foot above the FEMA anticipated level of flood waters. This information shall be provided with the building permit application. Response Utility Note 5 has been added to Sheet No. 1 - Site Layout and Utility Plan addressing this comment. Staff Comment 4 b Plans for landscaping or re -vegetation of disturbed areas to minimize the potential for soil erosion in the event of a flood. Evidence of initial re -seeding shall be required prior to issuance of a certificate of occupancy. Sw 04 44.4- #'L,9 - Response Staff Comment 4 c A determination that the proposed grading plan will not adversely affect any adjacent property owners. Response The site plan has been designed to eliminate adverse impacts to adjacent lots and it is the opinion of CIVCO Engineering, Inc. that if constructed according to plans, the grading will not adversely affect any adjacent property owners. Page 1 2 CIVCO Engineering, Inc. Vernal, Utah ---- CIVCO Engineering, Inc. Civil Engineering Consultants PO Box 1758 * 1256 W 400 5, Suite 1 Vernal, Utah 84078 May 4, 2016 Amended September 27, 2016 RE: CMH Flood Plain Development Permit (File No. FDPA-04-16-8445) 1.0 Summary The Chavez residence will be located on Lots 8 & 9 Rifle Village South; on Remington Ave. in Garfield County. This property is situated within a Zone AO Special Flood Hazard Area (SFHA) subject to inundation by the 1% annual chance flood. Zone AO is defined as "Flood depths of 1 to 3 feet (usually sheet flow on sloping terrain); average depths determined. For areas of alluvial fan flooding, velocities also determined." The flood zone is associated with alluvial fan flooding from Helmer Gulch, and the 100 year discharge is defined as 760 cubic feet per second (cfs). The flood depth in this area is defined as 1 foot with a velocity of 4 feet per second (fps). The entire parcel is located within the flood zone. The proposed residence will be a single story manufactured home with treated lumber framed perimeter foundation walls on concrete footings and chassis supports on spot footings throughout the crawl space. The structure will be anchored to resist flotation using tie straps on the chassis frame anchored to the exterior foundation. The finished floor elevation (FFE) will be 2 feet higher (5365.37) than the highest adjacent ground elevation (5363.37). The lot will be graded to provide positive drainage away from the structure in all directions. 2.0 County Floodplain Overlay Regulations The Garfield County Land Use and Development Code specifies general standards for development within a floodplain and specific standards that apply to the different types of SFHA zones that have been defined. The sections of that code that apply to the proposed project are 3- 301 B -G, 4-109, and 4-203. These sections are discussed in sections 2A, 2.2 and 2.3 of this report. 2.1 Garfield County Land Use and Development Code 3-301 3-301 B. General Standards. In the Floodplain Overlay, the following provisions are required for all New Construction and Substantial Improvements: 1. All New Construction or Substantial Improvements shall be designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. Phone (435)789-5448 * Fax (435)789-4485 Email: civco@civcoengineering.com The proposed residence will be a single story manufactured home with treated lumber framed perimeter foundation walls on concrete footings and chassis supports on spot footings throughout the crawl space. The structure will be anchored to resist flotation and lateral movement using tie straps on the chassis frame anchored to the exterior concrete foundation. Refer to attached foundation plans. 2. All New Construction or Substantial Improvements shall be constructed by methods and practices that minimize flood damage. The proposed project site has been designed to minimize the probability for floodwaters to impact the proposed structure. Refer to sections 4.0 Site Grading and 5.0 Flood Damage Protection. Construction materials have been specified according to the International Residential Code Section R401. Refer to attached foundation plan. 3. All New Construction or Substantial Improvements shall be constructed with materials resistant to flood damage. Foundation materials have been specified per the International Residential Code Section R401. Refer to section 4 Site Grading and to the attached foundation plan. 4. All New Construction or Substantial Improvements shall be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment, and other service facilities that are designed and/or located so as to prevent water from entering into or accumulating within the components during conditions of flooding. The finished floor elevation of the structure will be 5365.37 feet which is 1 foot higher than the reported flood water depth. A concrete slab for the air conditioning unit will be constructed with a finished top of slab elevation of 5364.37 feet. All electrical, heating, ventilation, plumbing, and air conditioning equipment, and other service facilities have been designed to keep those systems higher than the 100 -year floodwater elevation. Refer to section 5.0 Flood Damage Protection. 5. All Manufactured Homes shall be installed using methods and practices which minimize flood damage. For the purposes of this requirement, Manufactured Homes must be elevated and anchored to resist floatation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over -the -top or frame ties to ground anchors. This requirement is in addition to applicable State and local anchoring requirements for resisting wind forces. The structure will be anchored to resist flotation and lateral movement using tie straps on the chassis frame anchored to the exterior concrete foundation. The foundation has been designed according to the International Residential Code section R401. Refer to section 5.0 Flood Damage Protection and to the attached foundation plans. Page 1 2 6. All new and replacement water supply systems shall be designed to minimize or eliminate infiltration offlood waters into the system. The proposed project will connect to the Rifle City culinary water system. The water service lateral will be water tight and will terminate above the finished floor. 7. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration offlood waters into the system and discharge from the systems into flood waters. The proposed project will connect to the Rifle City sanitary sewer system. The sewer service lateral will be water tight and will terminate at or above the finished floor. 8. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding. Does not apply. There is no on-site waste disposal system. 3-301 C. Specific Standards. In the Floodplain Overlay, where BFE data has been provided. Does not apply. Base flood elevation has not been provided on FIRM. 3-301 D. Floodway. The proposed structure is not located within the floodway. The floodway will not be altered in any way by this project. Refer to attached FIRM. 3-301 E. Standards for Areas of Shallow Flooding. Areas designated as shallow flooding are located within the SFHAs. These areas have special flood hazards associated with Base Flood depths of 1 to 3 feet where a clearly defined channel does not exist and where the path of flooding is unpredictable and where velocity flow may be evident. Such flooding is characterized by ponding or sheet flow; therefore, the following provisions apply: 1. All New Construction and Substantial Improvements of residential structures have the Lowest Floor (including Basement) elevated above the highest adjacent Natural Grade at least 1 foot above the depth number specified in feet on the community's FIRM (at least 3 feet if no depth number is specified). The high point of the lot around the perimeter of the proposed structure has an elevation of 5363.37 feet and is located at the south east corner of the proposed structure. The finished floor elevation of the structure will be 5365.37 feet which is lfoot higher than the reported flood water depth of 1 foot. Page13 2. All New Construction and Substantial Improvements of nonresidential structures: Does not apply. This is a residential structure. 3. Adequate drainage paths around structures are required to guide flood waters around and away from proposed structures. Drainage shall not adversely impact adjacent properties. The lot will be graded to provide positive drainage away from the structure in all directions. The existing site is crowned and approximately one quarter of the lot drains northerly toward Remington Avenue. The remaining three quarters of the lot drains to the alley on the northern side of the lot. Proposed site grading will maintain the same general grading pattern. Refer to section 4.0 Site Grading and the grading and drainage plan attached to this document. 3-301 F. Properties Removed from the Floodplain by Fill. Does not apply. 3-301 G. Alteration of a Watercourse. Does not apply. 2.2 Garfield County Land Use and Development Code 4-109 4-109. DEVELOPMENT IN THE 100 -YEAR FLOODPLAIN. 4-109A. Overview. Applications for development within the 100 year Floodplain must receive a Floodplain Development Permit prior to any development. A floodplain development permit has been applied for. 4-109B. Review Process. Development in the 100 -Year Floodplain shall be processed pursuant to section 4-103, Administrative Review. A Floodplain Development Permit shall be issued upon approval of the application. Pending review by county. 4-109C. Review Criteria. A Floodplain Development Permit may be issued by the Director or designated Floodplain Administrator if it is found that the application is in conformance with section 3-301, Floodplain Overlay Regulations, and upon weighing the following relevant factors: 1. The danger to life and property due to flooding or erosion damage; Refer to section 3.0 Flood Plain Analysis. Page 1 4 2. The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner; Refer to sections 3.0 Flood Plain Analysis, 4.0 Site Grading and 5.0 Flood Damage Protection and the attached site plan drawings. 3. The danger that materials may be swept onto other lands to the injury of others; Refer to sections 3.0 Flood Plain Analysis, 4.0 Site Grading and 5.0 Flood Damage Protection and the attached site plan drawings. 4. The compatibility of the proposed use with existing and anticipated development; The proposed single family dwelling is located within a residential subdivision. S. The safety of access to the property in times of flood for ordinary and emergency vehicles; The proposed project will have no effect on the safety of access to the property by ordinary or emergency vehicles. 6. The costs of providing governmental services during and after flood conditions, including maintenance and repair of streets and bridges, and public utilities and facilities such as sewer, gas, electrical, and water systems; The proposed project will not increase the costs of providing governmental services during and after flood conditions. 7. The expected heights, velocity, duration, rate of rise, and sediment transport of the flood waters and the effects of wave action, if applicable, expected at the site; Refer to section 3.0 Flood Plain Analysis. 8. The necessity to the facility of a waterfront location, where applicable; Does not apply. 9. The availability of alternative locations, not subject to flooding or erosion damage, for the proposed use; Does not apply. 10. The relationship of the proposed use to the Comprehensive Plan for that area. The proposed single family dwelling is located within a residential subdivision. Page 5 2.3 Garfield County Land Use and Development Code 4-203 4-203 0. Floodplain Analysis. When a project is located within a Special Flood Hazard Area, if there is an indication or suggestion that a project is located in a SFHA, or if a project is a division of land or a PUD over 5 acres in size or proposes 50 lots or greater, the application must include a Floodplain Analysis. 1. Floodplain Specific Site Plan. The Applicant shall submit a Site Plan with specific information pertaining to the SFHA and shall include the following elements. The Floodplain Administrator may require, or the Applicant may choose to submit, a more detailed version of all or part of the Site Plan. Any elevation information shall be provided in the North American Vertical Datum of 1988. a. Base Flood boundary and water surface elevations; Refer to attached FIRM. b. Floodway boundary; Refer to attached FIRM. c. Channel of water course; Refer to attached FIRM. d. Existing and proposed topographic contours shown at vertical intervals of no greater than 2 feet; Refer to the attached site plan drawings. e. Elevation of the Lowest Floor, including Basement and garage, or each existing and proposed structure; Refer to the attached site plan drawings. f Proposed elevations to which structures will be flood proofed; Refer to the attached site plan drawings. g. Existing and proposed location, dimension, and elevation of proposed landscape alterations, structures, streets, water supply and any sanitation facilities; Refer to the attached site plan drawings. Page 1 6 h. Boundaries and total land area of existing and proposed impervious surfaces, including structures; and Refer to the attached site plan drawings. i. Location of existing water supply ditches, irrigation ditches and laterals. Refer to the attached site plan drawings. 2. A certificate from a qualified professional engineer or architect that the nonresidential flood -proofed structure shall meet the flood proofing criteria in section 3-301.C.2., Specific Standards for Nonresidential Construction. Does not apply. This is a residential structure. 3. An elevation certificate from a qualified professional surveyor, engineer or architect that certifies that all residential construction and mechanical equipment will be at least 1 foot above BFE. Refer to the attached elevation certificate, prepared by Kipp Land Surveying. 4. Description of the extent to which any watercourse or natural drainage will be altered or relocated as a result of proposed development. No watercourse or natural drainage will be altered or relocated as a result of the proposed development. Refer to the attached grading and drainage plan and FIRM. 5. An engineer's report completed by a qualified professional engineer experienced in hydrology or hydraulics, using a methodology acceptable to FEMA or the CWCB, that address the standards in section 3 -301.B -G. of this Code. This report has been prepared to specifically address the requirements of the Garfield County Land Use and Development Code 3 -301.B -G and standard level of care for development within an SFHA. 3.0 Flood Plain Analysis The Zone AO SFHA is an alluvial fan shallow flood plain. In an alluvial flood plain, the entire plain is not inundated during every flood event. An alluvial flood plain is formed over thousands of years. High velocity, sediment laden flood waters enter the flatter flood plain and gradually slow until the waters no longer have the energy required to transport the sediment they contain. When the waters slow sufficiently, the sediment settles out of the water creating deposits on the flood plain. As this process occurs over many years the alluvial fan changes shape topographically and flow paths are changed for each succeeding flood event. Page 1 7 The 100 year flood discharge at the mouth of Helmer Gulch is 760 cfs with a flood depth defined at a depth of 1 foot with a velocity of 4 fps. The width of the flood plain at the project, scaled from the firm map, is approximately 3500 feet. Using the continuity equation (Q = vA) we can solve for the width of flow of the 100 year flood, which will be approximately 190 feet. From this, in the event of a 100 year flood (0.1% chance) the percent chance for this property to be inundated is approximately 5% (190ft/3500ft). Other factors influencing flooding in this area include roads, grading due to land development and farming activities and the development of Helmer Gulch itself. The alluvial fan has been developed significantly over the past 40 years. The roads in the Rifle Village South Subdivision alone will do much to channelize and potentially split the flow of flood waters through this area. This report does not include the analysis of these impacts, but merely mentions them to show that by following the standards specified in the Garfield County Land Use and Development Code, the proposed residence will be reasonably protected from damage caused by flooding. A flood plain report prepared by Jerome Gamba & Associates in May of 1996 was referenced in the preparation of this report. A copy of that report has been attached to this document. 4.0 Site Grading The project site is currently vacant. Remington Avenue drains generally from east to west. The existing site is crowned and approximately one quarter of the lot drains northerly toward Remington Avenue. The remaining three quarters of the lot drains to the alley on the northern side of the lot. Proposed site grading will maintain the same general grading pattern. The high point of the lot around the perimeter of the proposed structure has an elevation of 5363.37 feet and is located at the south east corner of the proposed structure. The finished floor elevation of the structure will be 5365.37 feet which is lfoot higher than the reported flood water depth of 1 foot. Finished grade elevations around the structure will be 18 inches below the FFE or 6 inches above the existing grade. A concrete slab for the air conditioning unit will be constructed with a finished top of slab elevation of 5364.37 feet. The lot will be graded to provide positive drainage away from the structure in all directions. Refer to the grading and drainage plan attached to this document. 5.0 Flood Damage Protection The proposed project will connect to the Rifle City culinary water and sanitary sewer systems. Service laterals will be water tight and will terminate at or above the finished floor, thereby minimizing or eliminating the infiltration of potential flood waters into either system. To protect the proposed structure from flotation, collapse or lateral movement, the structure will be anchored using tie straps on the chassis frame anchored to the exterior concrete foundation at regular intervals along the north and south sides. Openings in the foundation wall have been designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of flood waters. Openings have been Page 18 designed using guidance found in FEMA Technical Bulletin 1-08 Openings in Foundation Walls and Walls of Enclosures. Refer to foundation plan. 6.0 Conclusion The proposed project has been designed with flood protection in mind. The Garfield County Land Use and Development Code and FEMA Technical Bulletin 1-08 have been used as for guidance in the selection of measures used to protect the proposed structure from flood damage. By constructing the site according to the proposed site plan and the Development Code, and following FEMA guidelines, the home will be reasonably protected from damage caused by flooding. Pre ed by: hn B. Barras Approved by: Vance V. King, P.E. Page 1 9 ELEVATION CERTIFICATE OMB Control Number: 1660-0008 Expiration 11/30/2018 SECTION D - SURVEYOR, ENGINEER, OR ARCHITECT CERTIFICATION This certification is to be signed and sealed by a land surveyor, engineer. or architect authorized by law to certify elevation information / certify that the information on this Certificate represents my best efforts to interpret the data available. 1 understand that any false statement may be punishable by fine or imprisonment under 18 U. S Code, Section 1001. Were latitude and longitude in Section A� 0 Check here if attachments provided by a licensed land surveyor? } Yes No ? ��'N0 LICE/V4 + °' C ".** Q�,L p /12,3.:‘/ �1 Certifig c Narpe J/ ,'1 ,�-^ n License Number G 9 f C) : A : • • •, Title / Cr CompanyNameName n ,r p79 • / • 38 ; o Address City„ Ste Zip Cod ii 'rte,; .•• ,• - - Sign Date Telephone a\�\+► l 6 2Zi-1,4 ql,_ atx>S'yt copy bo sides • • Ievatlon Certificate for (1) community official, (2 insurance agent/company, and (3) building owner Comments (including type of equipment and location , per C2(e), if applicable)" V) Co G f ),t Signature Date SEC E - BUI * - - VATION INFORMATION (XURVEY NOT REQUIRE) FOR ZONE AO AND ZONE A (WITHOUT BFE) For Zone AO nd A without BFE omplete Items E1 -E5. If the Certificate is intended to support a LOMA or LOMR-F request, complete Sections A. and C. o - 1 -E4, use natural grade, if available Check the measurement used In Puerto Rico only, enter meters. El Provide eTeVation information.for..the.f9tllowinq and check the appropriate boxes to show whether the elevation is above or below the ___- highest adjacent grade (HAG) and the lowest adjacent gra a 'Gr ------- ----- --- _ _ ..._ . _ ___.__ .._..------- a) Top of bottom floor (including basement, crawlspace. - / �`et ( meters ❑ above or 0 below the HAG. or enclosure) is b) Top of bottom floor (including basement crawlspace.( feet c meters [] above or [below the LAG or enclosure) is E2. For Building Diagrams 6 -9 with permanent flood openings provided in Section A Items 8 and/or 9 (see pages 8 -9 of Instructions). the next higher floor (elevation C2.b in the diagrams) of the building is - (' feet ( meters Ei above or I below the HAG. E3. Attached garage (top of slab) is- ( feet r . meters $ above or [j below the HAG. E4. Top of platform of machinery and /or equipment servicing the building is - i feet (` meters f above or ❑ below the HAG E5. Zone AO only: If no flood depth number is available, is the top of the bottom floor elevated in accordance with the community's floodplain management ordinance? ') yes r No (' Unknown The local official must certify this information in Section G SECTION F - PROPERTY OWNER (OR OWNER'S REPRESENTATIVE) CERTIFICATION The property owner or owner's authorized representative who completes Sections A, B, and E for Zone A (without a FEMA -issued or community -issued BFE) or Zone AO must sign here. The statements in Sections A, B, and E are correct to the best of my knowledge. Property Owner or Owner's Authorized Representative's Name Address City State ZIP Code Signature Date Telephone Comments (] Check here if attachments. FEMA Form 086-0-33 (7/15) Replaces al previous editions Page 4 Of 15 OMB Control Number. 1660-0008 Expiration. 11/30/2018 SECTION G - COMMUNITY INFORMATION (OPTIONAL) The IocaI official who is authorized by law or ordinance A, B, C (or E), and G of this Elevation Certificate. G10. In Puerto Rico only, enter meters to administer the community's floodplain management ordinance can complete Sections Complete the applicable item(s) and sign below. Check the measurement used in Items G8 - from other documentation that has been signed and sealed by a licensed surveyor, engineer, certify elevation information. (Indicate the source and date of the elevation data in the E for a building located in Zone A (without a FEMA -issued or community -issued BFE) or Zone is provided for community floodplain management purposes 01. IS The information in Section C was taken or architect who is authorized by law to Comments area below.) G2 0 A community official completed Section AO. G3 III The following information (Items G4 -G10) G4. Permit Number G5. Date Permit Issued G6 Date Certificate of Compliance/Occupancy Issued G7. This permit has been issued for r- New Construction 08. Elevation of as -built lowest floor (including basement) of the building G9 BFE or (in Zone AO) depth of flooding at the site: 010. Community's design flood elevation: 7 Substantial Improvement - ,-, feet ( meters Datum budding - t ` feet (. meters Datum - r' feet /- meters Datum Local Official's Name Title Community Name Telephone Signature Date Comments El Check here if attachments. FEMA Form 086-0-33 (7/15) Replaces at previous editions Page 5 of 15 LIMIT OF DETAILED STUD? ZONE A LIMIT OF DETAILED STUDY 19 ZONE AO (DEPTH (VELOCITY 4 FPS) Approximate project location ZONE f10 1)FPTH I (VELOCITY 5 FP) / ZONE C ZONE AO (DEPTH 1) (VELOCITY 6 FPS) 20 LIMIT OF DETAILED STUDY GARFIELD COUNTY APPROXIMATE SCALE. IN FEET 500 0 500 NATIONAL FLOOD INSURANCE PROGRAM FIRM FLOOD INSURANCE RATE MAP GARFIELD COUNTY. COLORADO (UNINCORPORATED AREAS) PANEL 1353 OF 1900 (SEE MAP INDEX FOR PANELS NOT PRINTED! COMMUNITY•PANEL NUMBER 080205 1353 B MAP REVISED: JANUARY 3, 1986 Federal Emergency Management Agency J ibis is an ol1clal copy of a portion or the above referenced good map. It wife extracted ulna F -MIT OrbUne. Tats map does not meat clamps. Of amendments Mich may have been made subsequent to Ma date on the MI. black. For the Inst product Information about National Flood Insurance Program Mood map check the FEMA Flood Map Store at www. ,o.0 Arne you