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HomeMy WebLinkAbout1.0 ApplicationOctober 16, 2019 APPLICATION FOR A DEVELOPMENT PERMIT FOR CONSTRUCTION ACTIVITIES PROPOSED WITHIN THE FLOOD FRINGE ASSOCIATED WITH PLACEMENT OF A MANUFACTURED OFFICE BUILDING ON A PARCEL AT, 25028 HWY 6 & 24 RIFLE COLORADO BEING WITHIN THE 100 -YEAR FLOODPLAIN -FLOOD FRINGE Representatives: Application Report: Sopris Engineering LLC 502 Main Street, Suite A3 Carbondale, Colorado. 81623 970.704.0311 Paul Rutledge Design Engineer Mark S. Beckler PLS Project Manager Applicant: William T. Lee (DBA Central Aggregates, Inc.) PO Box 1877, Rifle, Colorado. 81650 970.625.3598 Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 2 APPLICATION FOR A DEVELOPMENT PERMIT TABLE OF CONTENTS 1. Application Narrative Appendices A. Application Form and Payment Agreement Form (Pending) B. Letter of Authorization for Sopris Engineering LLC C. Warranty Deed confirming Applicant's Ownership D. Applicant's Title Policy identifying Mineral Rights (Pending) E. List of Property Owners within 200 feet of parcel F. Vicinity Map - three mile radius of subject property G. Site Plan showing Existing and Proposed Improvements H. Holding Tank Septic Design I. Stamped Tie Down Anchor System documentation J. Floodplain Exhibits K. Elevation Survey (dated 3/15/2019) — Bookcliff Survey Services, Inc. L. FEMA Elevation Certificate for Construction (Office Building) Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 3 APPLICATION FOR A DEVELOPMENT PERMIT FOR PLACEMENT OF A MANUFACTURED OFFICE BUILDING ON A PARCEL OF LAND LOCATED IN THE FLOOD FRINGE WITHIN THE 100 -YEAR FLOODPLAIN Property Owner Property Location: William T. Lee (DBA Central Aggregates, Inc.) PO Box 1877, Rifle, Colorado. 81650 970.625.3598 The subject property is a metes and bounds described parcel located in Section 17, Township 6 South, Range 93 West of the 6th P.M. in Garfield County. Garfield County parcel No. 217717100044. (Subject Parcel) Request for Approval: (a) A Development Permit for proposed construction within a portion of the Subject Parcel that is located within the delineated flood fringe (Zone AE). (b) Approval of construction in accordance with Garfield County's Regulations regarding Development Permits and work in a flood plain. SUMMARY OF REQUESTS The applicant is requesting a Development Permit in order to position a new manufactured building to function as an administrative office. The office will be staffed by five persons during the typical hours of operation of 7:00 am and 5:00 pm Monday to Friday with occasional occupation outside of normal business hours. The applicant requests the County's approval to perform the necessary improvements within the delineated flood fringe on the Subject Parcel. The work in the floodplain will involve permanent placement of a single story 1,440 ft2 manufactured office building (Office) and construction of; an Onsite Wastewater Treatment System (OWTS), utility services, employee/customer parking area (eight vehicles) and associated minor drainage re -grading within the proposed development envelope. All work in the floodplain will be performed within the limits of the established FEMA Zone AE flood fringe and above the existing river channel top of bank, at an existing grade higher than the established Base Flood Elevation (BFE). No work is proposed within the established FEMA floodway. The finish floor grade of the proposed Office will be more than one foot, as required, above the 100 - year BFE of 5283.5'. The structure will be raised above existing grade on an engineered support and anchoring system typical for manufactured building construction. The proposed construction does not involve the placement of any structures or materials that will adversely affect the existing flood hydrology or impact any sensitive area. Utility trenches will be restored to original grade and compacted. No construction or other work activities will be performed in the floodway therefore the existing floodway will be maintained with 0 -rise of flood levels and velocities. All Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 4 disturbed area on the site and within the flood fringe area will be stabilized and returned to existing conditions. Best management erosion control practices shall be in place and maintained as needed. EXISTING CONDITIONS AND FLOODPLAIN The Subject Parcel is a 33.99 acre active gravel pit designated within Rural Zoning as Manufacturing/Processing Land per Garfield County Assessor. The 6,000 ft2 proposed development envelope (Site) is within a re-claimed portion of the Subject Parcel outside of County setbacks. The Site's topography is flat, void of vegetation and unencumbered by ditches or wetlands. City of Rifle water and electricity are currently supplied to buildings adjacent to the proposed Office site. The site elevations and the FEMA FIRM mapping elevations on the attached site plan and the attached construction flood certificate are referenced to the NGVD 29 vertical datum in relationship to the current published FIRM map and FEMA statute. For consistency all elevations shown in this report are adjusted to NGVD 29 using a vertical adjustment of -3.917 feet from NAVD 88 elevations per National Geodetic Survey VERTCON data for the specific site. As required by Section 4-203-0 — 1. Floodplain Specific Site Plan elevations are shown in NAVD 88 as well as NGVD 29 vertical Datum. The proposed development within the flood fringe will occur to the North and outside of the floodway as defined by the established FEMA Floodplain line through the subject property. The 100 -year BFE at the most upstream point of the proposed Office is at an elevation of 5283.5' (extrapolated from published FIRM BFE data). The proposed single story office building's finish floor elevation is designed to be 36 inches above the existing grade of 5286.7' (resulting in a design finished floor elevation of 5289.7'). The floodplain information has been derived from the FEMA FIRM map, Community -Panel Number; 080205 1353 B, Index Date 12/15/1977 Revised 1/3/1986. The Regulations with respect to the floodplain require a Floodplain Development Permit for improvements and uses within the floodplain in accordance with Section 4-109 of the Land Use and Development Code. The Applicant's proposed construction and uses are inside of the flood fringe (Zone AE). The construction activities will be completed with appropriate flood proof construction including the stabilization of any placed fill as applicable by definition under the Floodplain Regulations Section 3-301. OVERLAY DISTRICT REGULATIONS Section 3-301, FLOODPLAIN OVERLAY REGULATIONS. All proposed improvements and uses described, in the summary of requests above, are permitted in accordance with Table 3-301 Floodplain Overlay Use Restrictions Table. These specifically include construction of permanent structures, sewage treatment facilities, underground utility Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 5 services, parking areas, driveways, storage yards, etc. easily moved and not subject to flood damage, that do not require asphalt paving. In accordance with Section 3-301 General Standards (B5) and Specific Standards (C4 a -b) the proposed structure will be installed using methods and practices which minimize flood damage and meet or exceed State and local anchoring requirements for resisting Zone 1 wind forces. The Office will be anchored on a permanent chassis, placed upon engineer approved piers 36 inches above ground level, utilizing engineered tie downs, earth augers and practices as depicted in the Professional Engineer stamped "Engineered Tie Down System Design and General Notes" The specified Minute Man MMA -650 (50 inch) earth auger anchor tie down system is engineered for FEMA Flood Hazard Zones A, AE & AH. Office access will be via engineered metal stairs and ADA approved ramp both equipped with code compliant railing systems. It is understood the constructed foundation system must be inspected by the County's Building Official prior to delivery of the structure and all aspects of building installation will be in accordance with the Housing and Urban Development (HUD) Part 3285—Model Manufactured Home Installation Standards (current as of September 23, 2019) and County Building Codes. The proposed Office building shall meet or exceed all required manufactured home certification requirements pursuant to the "National Manufactured Housing Construction and Safety Standards Act of 1974". Additionally, the building design will be in compliance with all Federal and State standards including but not limited to; construction, safety, wind zone, heating and insulation. Minor site re -grading will be performed to ensure positive drainage directing surface water away from the structure, protecting against erosion of foundation supports and to prevent water build- up under the building. A minimum of one-half inch per foot fall from the foundation for the first ten feet will be applied per HUD's Part 3285—Model Manufactured Home Installation Standards The proposed Office will connect to the available City of Rifle water and electric service, under the existing service agreements, and constructed according to code and regulation. The proposed new OWTS holding tank will be anchored and sealed to resist infiltration and buoyancy forces. To insure no infiltration of ground or surface waters into the OWTS, the holding tank will be installed in accordance with manufacturers' recommendations utilizing a watertight concrete tank with watertight ribbed PVC risers and sealed lids, covered with traffic rated access risers, iron rings and covers. The tank will be anchored to provide buoyancy compensation during time of elevated ground water. The OWTS design calls for installation of a liquid level alarm to light and sound at 75% tank capacity. All pipes shall consist of specified materials and tested to be waterproof so that no water infiltrates the system. All sewer pipe material should be gasketed SRD-26 pipe. Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 6 The level topography and open nature of the proposed site and surroundings does not require engineering or earthwork for driveway improvements to the Site or the Subject Parcel's existing access. The proposed construction and minor re -grading within the flood fringe will not be affected by floodwaters or cause adverse changes in flood patterns downstream since the existing grades are higher than the BFE. No geo hazards or wetlands have been identified on the developed site. No hydrologic condition has been identified that requires USACE determination or permitting. SUMMARY The applicable maps identify that the improvements are within the 100 -year delineated flood fringe. The construction in the established flood fringe (Zone AE) activities are limited to a single story 1,440 ft2 manufactured office building, an OWTS holding tank, utility services, parking area and minor grading within the proposed development envelope. The proposed construction includes an engineered tie down and pier system, placement of the structure typical for manufactured home construction and minor re -grading associated to assure positive drainage within the flood fringe only. Utility trenches will be restored to original grade and compacted. All utility service improvements will be installed in sealed conduits underground. The finished construction will be designed and constructed with materials that are resistant to flood damage. No construction activities are proposed that will restrict or otherwise adversely impact the current flood flow conditions. No storage or disposal of any hazardous materials is proposed within the floodplain. Section 4-109 - DEVELOPMENT IN THE 100 -YEAR FLOODPLAIN This section of the Land Use and Development Code permits construction as discussed herein. Because the proposed improvements are impacted by the 100 -year flood plain, Applicants acknowledge and herein address the applicable review criteria associated with Sub -sections A, B and C and Table 4-102 considering Development In The 100 -Year Floodplain to be granted by Decision. Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 7 Section 4-109(C) REVIEW CRITERIA With consideration of the Elevation Certificate and Bookcliff Survey (documents attached) the existing grades at the proposed site are in excess of three feet above the effective BFEs. Therefore it is our conclusion that no risk will result from the proposed development. More specifically, the relevant factors of sub section C are addressed here. 1. Proposed improvements lie within an open area with no possibility of endangerment to life or property. Ample area allows for the flow of potential floodwaters. The site is flat and erosion risk is low. 2. The proposed Office structure shall be placed on an engineered tie down system at an elevation well in excess of one foot above the BFE. The associated grading will be constructed to deflect any potential stormwater to its natural path and protect the anchoring system. 3. The remaining portion of the Subject Parcel and the adjacent land to the west, down gradient of the proposed development envelope, are both part of an active gravel pit, that includes a pond situated within the 100 year floodplain fringe. This pond potentially may serve to attenuate large storm flow runoff. Contents of the Office shall be contained within the structure. No materials or unanchored elements are included in the proposed design. 4. All proposed improvements are compatible with Floodplain Overlay Regulations 3-301. The proposed 1,440 ft2 Office structure will be situated within the 33.99 acre active gravel pit open for business during similar hours. 5. The current emergency vehicle access to the Subject Property and the proposed Office is maintained via US Highways 6 & 24 along the north border of the property and a granted crossing permit across the D.R.G.W. Railroad. The parcel is flat and open allowing for ample turn -around area to accommodate large emergency vehicles. 6. Proposed improvements require underground connection to existing utility services. All utility service improvements will be installed in sealed conduits underground and backfilled with Aggregate Base Course compacted to 95% relative compaction to insure resistance to potential storm or flood disturbance. 7. The stream reach within the vicinity of the Site lies within a broad floodplain. The proximate area has no development other than the gravel pit and is dominated by vacant lands vegetated with trees, shrubs and open grass areas. The adjacent area to the south of proposed development envelope, within the right bank flood fringe, is vegetated with minimal sloped terrain with established drainage paths that will serve to drain and attenuate excess storm or flood waters. The entire Subject Parcel consists of pervious Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 8 gravel and all existing and proposed grades on the site are above the BI -'E profile. The onsite soils are alluvial with high capacity for infiltration of surface water. Therefore no active stormwater management infrastructure is required Based on the site conditions summarized above, the height and velocities of potential backwater flood flows is minimal and is not expected to increase as a result of the proposed improvements. With respect to the existing vegetation, shallow topography above the BFE we do not expect any concern with wave action or erosion from receding flood backwater. Due to the large and relatively flat flood fringe area relative to the floodway the rate of rise and potential for sediment transport is expected to be low and insignificant in terms of the overall width of the flood zones. Therefore we do not believe that the items in Section 4-109, C-7 are applicable to this project. 8. No waterfront facility is applicable to the proposed improvements. 9. The delineated locations of the proposed site improvements have been determined to be appropriate based on the existing conditions with respect to survey topography. The layout and proposed grading maintains drainage flow paths with respect to the floodplain and will not affect conveyance of storm and flood waters. 10. All proposed Office building construction and uses are consistent with use in the flood fringe as specified in the Garfield County Land Use and Development Code. Section 4-201 APPLICATION MATERIALS The construction within the floodplain on the proposed Site will be designed and constructed in compliance with the applicable provisions of Table 4-201, Application Submittal Requirements. General application materials are included with this report. A Vicinity Map with three mile radius from the Subject property, an existing and proposed conditions Site Plan overview and Detail, a FEMA FIRM overlay are attached following this report and identified in the Application's Table of Contents. Section 4-203 — DESCRIPTION OF SUBMITTAL REQUIREMENTS This report and the Exhibit mapping sheets were prepared by Sopris Engineering based on our review of the relevant flood conditions and the documents provided by other consultants as listed here. Subject Property Elevation Survey (dated 3/15/2019) — Bookcliff Survey Services, Inc.; Stamped Tie Down Anchor System. Design & General Notes - Minuteman Anchors Inc. All supporting documents pursuant to the applicable Section 4 -203 -Sub -sections are addressed within this report and or included as Appendices hereafter. Any additional requirements of Section 4-203 Sub -sections deemed applicable will be submitted as needed for the site specific conditions prior to building permit application. Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 9 Section 4-203-E GRADING AND DRAINAGE PLAN The following narrative further describes activities that will be implemented on site associated with stabilization and best management practices. Detailed plans addressing all applicable code requirements will be prepared and submitted for building permit application. Topographic mapping indicates that the Site will not receive storm water from up -gradient offsite sources due to existing flow paths, neighboring topography and established vegetation. During construction, any runoff will be controlled and attenuated on the site by direct infiltration into the ground and temporary retention in surface depressions. Potential erosion and sedimentation from disturbed areas will be controlled by installation of strategically placed silt fencing and wattles (erosion logs) where necessary. These measures in conjunction with material storage and management will ensure little to no potential risk during a storm or flood event. Recovery of disturbed areas will be completed after construction activity. The following material storage and management practices are to be implemented at the Site: • Adequate garbage, construction waste, and sanitary waste handling, and disposal facilities are provided to keep the Site clear of potential pollutants and pollutant sources.. • Materials and wastes no longer required for the construction will be removed from the Site and properly disposed. • Potential pollutants and pollutant sources are handled in such a way as to minimize contamination risk. • Chemicals and petroleum products stored on-site and outside will be covered, placed in secondary containment, secured chemical storage lockers, and protected from accidental release on designated areas above and outside of the flood fringe zone area. Section 4-203-N —1. b, i & j WASTEWATER MANAGEMENT AND SYSTEM PLAN An Onsite Wastewater Treatment System (OWTS) is proposed for the proposed Office, and is being designed by Sopris Engineering. The proposed OWTS will consist of a 2,000 gallon concrete septic tank with sealed risers and lids and equipped with a 75% capacity liquid level alarm. The system will be a closed non - discharging system that will serve as a holding tank that will be periodically pumped as needed. Therefore the system does not include an absorption field or require a soils test. Section 4-203-0 — 1. FLOODPLAIN ANALYSIS All the listed items in Sub -section (1) a -i are addressed in this report, the FIRM Overlay exhibit maps and the Elevation Certificate for Construction. In summary, the elevations shown here are based on NGVD 29 vertical datum unless stated otherwise. The 100 -year BFE at the most upstream point associated with the structure within the flood fringe is at an approximate elevation of 5283.5'. Applicant: Central Aggregates Inc. SE Job No. 19038.02 October 16, 2019 Page 10 The upstream point BFE was extrapolated from the BIi'Es published in FEMA FIRM Panel 0802051353 B Index Date 12/15/1977 Revised Date 01/03/1986. Vertical datum NGVD 29. Existing grade at the Site is 5286.7, per Bookcliff 2019 survey (5290.6' NAVD 88*). The proposed Office building is designed to be raised 36 inches above existing grade with a design finish floor elevation of 5289.7' 6.2' above the BFE and greater than the minimum required one foot above the BFE. *NAVD 88 elevations were adjusted to NGVD 29 using a conversion of -3.917 per NGS VERTCON. APPENDICES The following documents are appended hereto: A. Application Form and Payment Agreement Form (Pending) B. Letter of Authorization for Sopris Engineering LLC C. Warranty Deed confirming Applicant's Ownership D. Applicant's Title Policy identifying Mineral Rights (Pending) E. List of Property Owners within 200 feet of parcel F. Vicinity Map - three mile radius of subject property G. Site Plan showing Existing and Proposed Improvements H. Holding Tank Septic Design I. Stamped Tie Down Anchor System documentation J. Floodplain Exhibits K. Elevation Survey (dated 3/15/2019) — Bookcliff Survey Services, Inc. L. FEMA Elevation Certificate for Construction (Office Building) Garfield County Community Development Department 108 8t" Street, Suite 401 Glenwood Springs, CO 81601 (970) 945-8212 www.garfield-county.com LAND USE CHANGE PERMIT APPLICATION FORM TYPE OF APPLICATION Owner/Applicant Name: C NT(Z fL Oa -6 e-rgiET Phone: ( /70 62S- 3 S` e Administrative Review " Development in 100 -Year Floodplain E-mail: ri Cr lecreek5 ►1eQ 5Mgi 1. eaM Limited Impact Review 0 Development in 100 -Year Floodplain Variance Mailing Address: Sn Z t1fh4/ sr Major Impact Review Q Code Text Amendment Amendments to an Approved LUCP 0 Rezoning QZone District PUD ❑PUD Amendment LIR EMIR SUP Physical/Street Address: 25—"2E3 14/W 7 4 24 Qit t f Co Minor Temporary Housing Facility Administrative Interpretation Zone District: Property Size (acres): 3311 kr- Vacation of a County Road/Public ROW Appeal of Administrative Interpretation Location and Extent Review Areas and Activities of State Interest Comprehensive Plan Amendment' DAccommodation Pursuant to Fair Housing Act Pipeline Development Variance Time Extension (also check type of original application) INVOLVED PARTIES Owner/Applicant Name: C NT(Z fL Oa -6 e-rgiET Phone: ( /70 62S- 3 S` e Mailing Address: Po 6X I g 7 7 City: %ZIfLF State: Zip Code: 8(6Sn E-mail: ri Cr lecreek5 ►1eQ 5Mgi 1. eaM Representative (Authorization Required) Name: S. Arcata_ C Phone: ( q70) 70* eigll Mailing Address: Sn Z t1fh4/ sr City: et4e 40Al Atz.4 State: Zip Code: e/b o7 nl beckier € Sd rii(e n M E-mail: � ,S' C7 PROJECT NAME AND LOCATION Project Name: Assessor's Parcel Number: 2/ 7 7 - 17 I- O O- O 44 4 Physical/Street Address: 25—"2E3 14/W 7 4 24 Qit t f Co Legal Description: Mei 14 60.4a1=4 DCSe/W/10d (/Tv4 mi SeLr7nd/ /7 76 S - izi3 a a< 6 7' P M . Zone District: Property Size (acres): 3311 kr-