Loading...
FS9903-AG 990511 V � f AGENDA RE,UEST FORM The City With A Beautiful Future IC 9 CITY COUNCIL MEETING: May 11, 1999 ITEM # ITEM CAPTION: Consider approval of a variance for an Interim Permit on approval of City Engineer to Floodplain Management Ordinance No. 94 -639, Article 4, Section B, Item 11(ga), which states that the Floodplain Administrator must "assure that conditional approvals are received from Federal Emergency Management Agency before a Floodplain Development Permit is issued" for the proposed 58 acre development east of MacArthur Boulevard and south of Sandy Lake Road. APPROVED BY SUBMITTED BY: Kenneth M. Griffin, P.E. CITY C. NCIL TITLE: Director of Engineering /Public Works D ATE ,� 9 STAFF COMMENTS: See attached memo. ._ / / ;„ r BUDGET AMT. $ AMT. EST. $ +\ -BID $ FINANCIAL COMMENTS0 DIR. INITIALS: FIN. REVIEW: 0 CITY MANAGER REVIEW: Agenda Request Form - Revised 2/99 Document Name: # #05113 MEMORANDUM FROM THE DEPARTMENT OF ENGINEERING To: Mayor and City Council From: Kenneth M. Griffin, P.E., Dir. of Engineering /Public Works Y-1 Date: May 11, 1999 RE: Consider approval of a variance for an Interim Permit on approval of City Engineer to Floodplain Management Ordinance No. 94 -639, Article 4, Section B, Item 11(qa), which states that the Floodplain Administrator must "assure that conditional approvals are received from Federal Emergency Management Agency before a Floodplain Development Permit is issued" for the proposed 58 acre development east of MacArthur Boulevard and south of Sandy Lake Road. The 58 acres in question is a triangular tract of land fronting on Sandy Lake Road between the vacant shopping center at the southeast corner of MacArthur Blvd. and Sandy Lake and the Riverchase Development. A portion of the land fronts on MacArthur Blvd. and is immediately south of the Wellington Apartments. The majority of the property in question is not within the designated floodplain. The reclamation request is for permission to do some filling along the fringes of and adjacent to the TU power lines and an area south of the Wellington Apartments. All the areas to be filled lie within areas of ineffective flow. In essence, this means this is an area where the water from the Elm Fork would backup and pond. The filling of the property will have no impact upon the elevation of the water surface in the general area. The only impact of filling will be a loss in valley storage. The development is proposing a series of ponds along the east side of the property adjacent to the TU power lines to compensate for the loss of valley storage. There has been some time delay on processing the report to FEMA because the developers' consultant finalized the study based on erroneous information from FEMA's consultant, Michael Baker Engineering. Because it takes typically six to eight weeks for FEMA's approval of a Flood Study and because the fill is within areas of ineffective flow, the developer is requesting that he be allowed to proceed with the reclamation on the property. The report, as submitted and processed to FEMA, is in compliance with the City's Floodplain Ordinance. Therefore, staff offers no objections to the variance request with the following stipulations: 1. A letter is provided from FEMA stating that they have all necessary information, including fees, to proceed with the review of the Flood Study. 2. Any changes requested by FEMA during the Flood Study be complied with prior to acceptance by the City. 3. No Building Permits will be issued on any lots within the development until the Flood Study has been approved by FEMA. Council may recall that the City has granted similar variances to Big Cedar Subdivision, Villages of Coppell Phase III and Windsor Estates. Compliance with the above stipulations will be monitored. Therefore, staff recommends approval of this request and will be available to answer questions at the Council meeting. "CITY OF COPPELL ENGINEERING - EXCELLENCE BY DESIGN" EMail Subj: City of Coppell. TX - Ken Griffin Date: 99 -04 -19 12:31:29 EDT From: LBITTNER @mbakercorp.com (Laura Bitiner) To: RONMOR7777@aol.com Ron. I just spoke to Ken Griffin and I think I was unclear about what we discussed regarding CLOMRs in Laredo. As we talked about. previously issued CLOMR existing conditions models should be used as base models (or as the "effective model ") in new requests for LOMRs/CLOMRs because this information acts as the best available data in the area. However, we cannot do LOMR -Fs, CLOMR -Fs, or LOMAs based on existing condition CLOMR models. LOMR -Fs. CLOMR -Fs. and LOMAs can only be issued based on effective BFEs. (Unless the area is in Zone A where no effective BFEs exist.) The same is true for preliminary maps. Preliminary maps can be used as best available data for floodplain management but will not be used for insurance purposes until they become effective. I apologize if this has created some confusion. Please call me at (703) 317 -6292 or email me if you would like to discuss this further. Laura ( SI - 1)6 e5 134 Morrison Hydrology Engineering, Inc. 210 Arnold Ave. Arlington, Texas 76010 Metro (817) 461 -0321 Fax (817) 274 -1338 E -Mail: ronmor7777 @nol.com 4 )ze /o c April 22. 1999 Mr. Kenneth M. Griffin. P.E. Assistant City Manager and City Engineer City of Coppell 255 Parkway Blvd. P.O. Box 478 Coppell. Texas 75019 Off 214 -304 -3679 Metro 214 -471 -2251 Fax 214 -304 3673 Re: Flood Study of the Elm Fork of the Trinity River For a 10 and 48 Acre Parcel of Land South of Sandy Lake Road And East of MacArthur Road in Coppell, Texas Dear Mr. Griffin: We assume you received the information from Ms. Laura Bittner (Email attached) regarding the methodology for submitting a Conditional Letter of Map Revision (CLOMR) and Conditional Letter of Map Revision based on Fill (CLOMR -F) requests. As we understand it. a CLOMR submittal must use "best available data" which means that the approved existing condition from the latest CLOMR (or LOMR) approved by FEMA must be used as base conditions. We were aware of this requirement. What we were not aware of is that this does not apply to a CLOMR -F. For a CLOMR -F you must use the effective model whether it has been modified by a CLOMR or not. This particular site shows on the FEMA FIRM map as being at elevation 446 + / -. The existing condition from the latest approved CLOMR shows an elevation of 444 + / -. The Corps LIECRAS model (which has been reviewed by FEMA's technical consultant and approved, but has not been through the FEMA approval process) shows an elevation of 442 + / -. In conversations with FEMA and the FEMA technical consultant we understand that this last model will be official soon (probably this year). So by the time the project is finished we will be required to use the Corps HECRAS model for as -built conditions. If we wait until the Corps HECRAS is officially approved the property can be removed from the floodplain by filling to 442 + / -. Naturally, the city will require fill to one foot above the ultimate condition as per ordinance. The problem with waiting for this final FEMA approval of the HECRAS model is that we do not know within a reasonable period when this will happen, and the timing of this project is critical. If we use the CLOMR -F procedure with an elevation of 446 +/- the cost of the extra fill is excessive and we are not sure that there is sufficient storage compensation for this elevation. Morrison Hydrology Engineering, Inc. 10 and 48 Acre Parcel of Land South of Sandy Lake Road And East of MacArthur Road in Coppell, Texas Page —2- So to correct the problem we are preparing a CLOMR submittal for the project. We discussed this with Ms. Laura Bittner yesterday and she informed us that FEMA would accept this project for review as a CLOMR submittal. We will provide this CLOMR report to you Monday. LP c £ kJ/. c. 4 11_-_110) ° iC SO f'fv■ The most pressing concern at this point is time. If this revised submittal must be reviewed by your floodplain review consultant it will delay the project to a point that the developer tells us that it puts the completion of the project in question. Please let me know what you will require. Thank you for your attention in this matter. Sincerely, dYt� Ronald W. Morrison. P.E.. C.F.M. Senior Hydrologist CC: Mr. Lou Lebowitz Sandy -Mac Partners Mr. Dayton Macatee Macatee Engineering I Ken Gri in - ou ie.owi 'rope ` o an.y a e 'oa•, nrn oo•pain ply Page 1 From: Laura Bittner <LBITTNER @mbakercorp.com> To: City_of Coppell. Town_ Center (kgriffin),Allegro5.Hub... Date: 5/6/99 1:57PM Subject: Lou Liebowitz Property South of Sandy Lake Road, TrinityFloodplain -Reply Ron and Ken, We received the CLOMR request for this property on May 5, 1999. We will do our preliminary review and send an acknowledgment letter to you within the next 5 working days. Laura Bittner • Michael Baker Jr., Inc. This is notification from FEMA's CONSULTANT, Michael Baker Jr., Inc., that they have received all necessary documents to proceed with the review of the flood study on the proposed 58 acre development east of MacArthur Blvd., and south of Sandy Lake Road.