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HomeMy WebLinkAbout2.0 Staff Report.....RESOURCE ' ■••UU E N G I N E E R I N G INC. David Pesnichak Garfield County Building and Planning Dept 108 8th Street, Suite 201 Glenwood Springs CO 81601 RE: Hoffmaster Family Partnership, LLLP Floodplain Development Permit Dear David: February 26, 2008 At the request of Garfield County, Resource Engineering, Inc. (RESOURCE) has reviewed the Floodplain Development Permit Application submitted by Hoffmaster Family Partnership, LLLLP dated December 18, 2007 with supporting documentation dated up to January 10, 2008. The property is located at 314 Flying Fish Road along the Roaring Fork River approximately one mile east of Catherine Store. The proposed activity within the floodway is construction of 4,000 square foot addition to an existing 1,800 square foot single family residential structure built in 1979. FACTUAL DETERMINATION Application of the GARCO Floodplain regulations is based on the following determination of facts. 1. The existing structure was constructed entirely within the regulatory floodway prior to the effective date of the Flood Insurance Rate Map (FIRM) and is a pre -FIRM structure. 2. The construction cost of the proposed addition is more than 50% of the value of the existing structure, which classifies the proposed project as a "substantial improvement." 3. The proposed residential addition is entirely within the regulatory floodway. APPLICABLE REGULATIONS AND CRITERIA Based on the facts above, the proposed project must first meet the requirements of floodway encroachment review in Section 6.09.04. Assuming the proposed project complies with floodway encroachment review regulations, both the proposed additions and pre -FIRM structure must comply with the standards set forth in Section 6.09.01 and 6.09.02. The proposal must also be consistent with the floodplain management goals of the Floodplain Regulation as generally evaluated in items a through j of Section 6.08.02(2). ANALYSIS The floodway encroachment review of Section 6.09.04 requires that the proposed project result in a 0.00 foot rise in flood levels during the occurrence of the base flood discharge. The submittal states that a HEC -RAS analysis indicates no rise in flood 1i08 Consulting Engineers and Hydrologists 909 Colorado Avenue • Glenwood Springs, CO 81 601 • (970) 945-6777 • Fax (970) 945-1137 David Pesnichak February 26, 2008 Page 2 levels and the summary table shows that the flood levels actually decrease as a result of the encroachment. The HEC -RAS model data and analysis was not included in the application and we are unable to review this finding. An encroachment in the floodway should, by definition, show an increase in flood elevation. We recommend that the HEC - RAS model be provided for review prior to any approval of the permit. The applicable standards of Section 6.09.01 and 6.09.02 appear to be met for both the existing pre -FIRM structure and the proposed addition. The proposed project does not appear to be consistent with the goals of the floodplain management program. The objective is to ensure that the floodway is reserved to do its natural job, which is to convey floodwater without obstruction. The preferred approach by FEMA is to avoid all development in the floodway. The scale of this project in relationship to the existing structure is essentially new construction. If this project was new construction, it could not meet the floodway encroachment criteria and would not be approved. The application does not address the availability of alternative locations on the property outside of the floodway. The neighboring houses are outside of the floodway, although the property immediately upstream of this project appears to have some floodway encroachments. It is debatable whether a driveway located in the floodway and submerged in one foot of water is safe. If is also debatable whether a house isolated in the floodway does not present a danger to life in the event of flooding. RECOMMENDATIONS We recommend denial of the permit application as submitted based on the substantial improvement being inconsistent with the intent and goals of the floodplain management program. In addition, the HEC -RAS model results appear to be contrary to the expected answer. The model should be submitted and reviewed prior to any approval of the permit. Please call if you have any questions or need additional information. Sincerely, RESOURQ. E ' (N . ERING, INC. Mic ael J. E -`on, P.E. Water Reso1jrces Engineer MJE/mmm 885-53.0 K:1Clients1885 GARC0153.0 HOFFMASTER FAMILY\ David Pesnichok floodplain permit 885.doc RESOURCE ENGINELHING I N C March 13, 2008 Scot Broughton Architects c/o Scot Broughton 23280 Two Rivers Road, Unit 3 Basalt, CO 81621 BUILDING & PLANNING DEPARTMENT RE: FLP1108 — Russell (Hoffmaster Family Partnership, LLLP) Floodplain — 314 Flying Fish Road Dear Mr. Broughton, This letter is in response to the Floodplain Development Permit application (designated as FLP 1108) you submitted to the County on behalf of Tom Russell (Hoffmaster Family Partnership, LLLP) and for a property described as 314 Flying Fish Road, Garfield County. This letter is to inform you that following a review of the application by Planning Staff and the Garfield County Engineer that this application has been denied due to non-compliance with Section 6.09.04 of the Zoning Resolution of 1978. At this point, Staff sees that there are two ways to which the Applicant can continue to work toward approval of this application: 1. The Applicant may accept the above determination as the final Director's decision and in accordance with Section 6.08.02(3)(d) of the Zoning Resolution of 1978 as amended, the Applicant may request a Reconsideration of the Director's Decision. This request must be in writing and must be submitted no later then ten (10) calendar days of the date of written notice of the decision by the director (March 28, 2008). This request will lead to a noticed public hearing before the Board of County Commissioners to formulate a final decision of approval or denial. 2. The Applicant may submit the HEC -RAS model data and analysis which was not included within the application to the Garfield County Planning Department and Engineer for additional review. The submittal of the HEC -RAS model data and analysipmthst be eceived by the Garfield County Planning Department no later then Aelli ;-2 (deadline for final Director's Decision). This submittal must be accompanied by a letter waiving the thirty (30) day decision deadline required in Section 6.08.02(3)(b) of the Zoning Resolution of 1978 and must request that the additional information be reviewed as a part of the previously submitted application (FLP 1108). The waiver of this deadline will allow time for the Garfield County Engineer to review the additional information and the Planning Director to review the comments submitted by the Garfield County Engineer. At 108 Eighth Street, Suite 401 • Glenwood Springs, CO 81601 (970) 945-8212 • (970) 285-7972 • Fax: (970) 384-3470 this point the Applicant will be informed of the Director's final decision of approval or denial. This decision can then be challenged at the request of the Applicant in accordance with Section 6.08.02(3)(d) identified above. Do not hesitate to contact this office in the event you have any questions. Best regards, Fred Jarman, AICP Floodplain Administrator Director, Building and Planning Department (970).945-8212 Enclosed: Garfield County Engineer Review dated February 26, 2008 (Resource Engineering, Inc.) Cc: Michael Erion, PE, Resource Engineering, Inc. David Pesnichak, Senior Planner 2 .."...'RESOURCE ■.nu ■■.I. E N G I N E E R I N G I N C. David Pesnichak Garfield County Building and Planning Dept 108 8th Street, Suite 201 Glenwood Springs CO 81601 RE: Hoffmaster Family Partnership, LLLP Floodplain Development Permit February 26, 2008 Dear David: At the request of Garfield County, Resource Engineering, Inc. (RESOURCE) has reviewed the Floodplain Development Permit Application submitted by Hoffmaster Family Partnership, LLLLP dated December 18, 2007 with supporting documentation dated up to January 10, 2008. The property is located at 314 Flying Fish Road along the Roaring Fork River approximately one mile east of Catherine Store. The proposed activity within the floodway is construction of 4,000 square foot addition to an existing 1,800 square foot single family residential structure built in 1979. FACTUAL DETERMINATION Application of the GARCO Floodplain regulations is based on the following determination of facts. 1. The existing structure was constructed entirely within the regulatory floodway prior to the effective date of the Flood Insurance Rate Map (FIRM) and is a pre -FIRM structure. 2. The construction cost of the proposed addition is more than 50% of the value of the existing structure, which classifies the proposed project as a "substantial improvement? 3. The proposed residential addition is entirely within the regulatory floodway. APPLICABLE REGULATIONS AND CRITERIA Based on the facts above, the proposed project must first meet the requirements of floodway encroachment review in Section 6.09.04. Assuming the proposed project complies with floodway encroachment review regulations, both the proposed additions and pre -FIRM structure must comply with the standards set forth in Section 6.09.01 and 6.09.02. The proposal must also be consistent with the floodplain management goals of the Floodplain Regulation as generally evaluated in items a through j of Section 6.08.02(2). ANALYSIS The floodway encroachment review of Section 6.09.04 requires that the proposed project result in a 0.00 foot rise in flood levels during the occurrence of the base flood discharge. The submittal states that a HEC -RAS analysis indicates no rise in flood Consulting Engineers and Hydrologists 909 Colorado Avenue ■ Glenwood Springs. CO B1601 ■ (970) 945-6777 ■ Fex (970) 945-1137 David Pesnichak Page 2 levels and the summary table shows that the flood levels actually decrease as a result of the encroachment. The HEC -RAS model data and analysis was not included in the application and we are unable to review this finding. An encroachment in the floodway should, by definition, show an increase in flood elevation. We recommend that the HEC - RAS model be provided for review prior to any approval of the permit. The applicable standards of Section 6.09.01 and 6.09.02 appear to be met for both the existing pre -FIRM structure and the proposed addition. The proposed project does not appear to be consistent with the goals of the floodplain management program. The objective is to ensure that the floodway is reserved to do its natural job, which is to convey floodwater without obstruction. The preferred approach by FEMA is to avoid all development in the floodway. The scale of this project in relationship to the existing structure is essentially new construction. If this project was new construction, it could not meet the floodway encroachment criteria and would not be approved. The application does not address the availability of alternative locations on the property outside of the floodway. The neighboring houses are outside of the floodway, although the property immediately upstream of this project appears to have some floodway encroachments. It is debatable whether a driveway located in the floodway and submerged in one foot of water is safe. If is also debatable whether a house isolated in the floodway does not present a danger to life in the event of flooding. February 26, 2008 RECOMMENDATIONS We recommend denial of the permit application as submitted based on the substantial improvement being inconsistent with the intent and goals of the floodplain management program. In addition, the HEC -RAS model results appear to be contrary to the expected answer. The model should be submitted and reviewed prior to any approval of the permit. Please call if you have any questions or need additional information. Sincerely, RESOURC_ /N ERING, INC. Mic aeI J. Eon, P.E. Water Res. rces Engineer MJE/mmm 885-53.0 K\CBent51885 GARCO53.0 HOFFMASTER FAMILY1 David Pesnichak Boodplain pemit B85.dao RESOURCE .....E N G 1 N E E R I N G I N C. ■■■■■ RESOURCE ■■■■. ■ ■■■■ ■ ■■■■ E N G I N E E R I N G INC. David Pesnichak Garfield County Building and Planning Dept 108 8th Street, Suite 201 Glenwood Springs CO 81601 RE: FLP 1108 — Hoffmaster Family Partnership Review of Supplemental Submittal Dear David: April 21, 2008 At the request of Garfield County, Resource Engineering, Inc. (RESOURCE) has reviewed the supplemental submittal for the floodplain permit application of the Hoffmaster Family Partnership, LLLP. The submittal is a hard copy of the HEC -RAS computer model output for the existing and proposed conditions prepared by Rhino Engineering. RESOURCE previously consulted with the FEMA Colorado Community Coordinator, Thuy Patton at the Colorado Water Conservation Board. Her response was received after our February 26, 2008 review letter and we have incorporated her comments and input in this review. HEC -RAS MODEL The HEC -RAS computer modeling analysis should be revised to address the following items. 1. The encroachment analysis should be based on the computer model used to develop the floodway shown on the NFIP maps. A no rise certification would require verification floodplain and floodway models, existing conditions (with inserted cross-sections at the project site) floodplain and floodway models, and proposed conditions models. 2. The cross section data should be expanded based on the Sopris Engineering survey so that the cross-section end points don't have to be extended to contain the flow. 3. The model indicates that divided flow was computed for several cross sections. The high point in the cross-section data should be removed (not sure how topo under the existing house could be determined). 4. The blocked obstruction should be modeled with an additional cross-section at the upstream face of the proposed building and a cross section immediately downstream of the building. Cross section RS 15 should be moved approximately 20 feet downstream. RECEIVED APR 2 2 2008 GARFiELD COUNTY BUILDING & PLANNING Consulting Engineers and Hydrologists 909 Colorado Avenue ■ Glenwood Springs, CO 81 601 ■ (970) 945-6777 • Fax (970) 945-1137 David Pesnichak Page 2 GENERAL CONCERN April 21, 2008 Thuy Patton expressed concern that the proposed construction in the floodway is not consistent with the intent of the NFIP program. We reiterate our recommendation that the Applicant must address the potential to locate the structure outside of the floodway in accordance with Section 6.08.02(2) of the Garfield County Floodplain Regulations. In the event the revised modeling still shows a "no rise" in flood levels and the County approves the permit, the Applicant's engineer should provide a "No Rise Certification" like the attached provided by FEMA. Please call if you have any questions or need additional information. Sincerely, RESOURCE ,%/7//1 Michael J. Er Water Res NNE; RING, INC. n, I .E. rces Engineer MJE/mmm 885-53.0 10Clients1885 GARC0153.0 HOFFMASTER FAMILY\David Pesnichak flp 1108.doc Attachment RESOURCE ■EEE■ E N G I N E E E I N G INC "NO -RISE" CERTIFICATION This is to certify that I am a duly qualified registered professional engineer li- censed to practice in the State of It is further to certify that the attached technical data supports the fact that proposed (Name of Development) will not impact the 100 -year flood elevations, floodway elevations, or floodway widths on (Name of Stream) at published sections in the Flood Insurance Study for (Name of Community) dated (Study Date) and will not impact the 100 -year flood elevations, floodway elevations, or flood - way widths at unpublished cross-sections in the vicinity of the proposed devel- opment. Attached are the following documents that support my findings: Date: Signature: Title: {SEAL} . OURCE .... ■...■ E N G I N E E R I N G INC. Mr. David Pesnichak Garfield County Building and Planning Dept 108 8th Street, Suite 201 Glenwood Springs CO 81601 RE: FLP 1108 — Hoffmaster Family Partnership Review of Revised Project and Analysis Dear David: September 19, 2008 RECEIVED SEP 2 2 2008 GAREIE ID COUNTY 3UILDiNG & PLANNING At the request of Garfield County, Resource Engineering, Inc. (RESOURCE) has reviewed the new submittal with a revised project and analysis for the floodplain permit application of the Hoffmaster Family Partnership, LLLP. The submittal includes a three ring binder and CD of the HEC -RAS computer model analysis prepared by Rhino Engineering, Inc. dated July 30, 2008. A cover letter and plan map prepared by Scot Broughton Architects dated August 14, 2008 is also included in the notebook. Our comments are presented below. TECHNICAL ANALYSIS — HEC -RAS MODEL The technical analysis was prepared by a Colorado Registered Professional Engineer who is also a Certified Floodplain Manager (CFM - a FEMA accreditation). The analysis addresses technical concerns previously identified by RESOURCE and indicates that the proposed house addition, as modified with a cantilever overhang structure, results in no rise in the base flood elevation. This meets the requirements of Section 6.09.04 of the GARCO Floodplain Regulation. FLOODPLAIN MANAGEMENT Although the analysis demonstrates compliance with technical criteria, as noted in RESOURCE's April 21, 2008 review letter to David Pesnichak, there is floodplain management concerns about locating a substantially new house in the floodway. RECOMMENDATION RESOURCE does not support issuance of a permit for a substantially new house in the floodway. However, we believe the County can issue a permit for the project based on the technical analysis compliance presented in the revised submittal and a statement from a Colorado Registered Professional Engineer (CRPE) that the proposed project meets all of the criteria and requirements of the GARCO Floodplain Regulation. The original submittal makes this statement, but it is not within a report that is distinguished to be prepared by a CRPE. Any permit approval should require that an as -built "No Rise" Certification and an Elevation Certification be prepared by a CRPE prior to issuance of a Certificate of Occupancy or other final construction approval by the County. Consulting Engineers and Hydrologists 909 Colorado Avenue • Glenwood Springs, CO 81 601 • (970) 945-6777 ■ Fax [970] 945-1137 September 19, 2008 Mr. David Pesnichak Page 2 Please call if you have any questions or need additional information. Sincerely, RESOURCE .NG EERING, INC. f; Michael Ji ' r'•n, P.E. Water R ; ources Engineer MJE/mmm 885-53.0 david pesnichak flp 1108 revised analysis ::::RESOURCE ::::: U\•U. E N G I N E E R I N G INC.