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Item VII (G) Discussion/Action re: Lake Meadow/Prairie Lake Drainage Basin StudyAgenda 8-04-98 Item VII G JAMES W. SHIRA, P.E. CITY ENGINEER / UTILITIES DIRECTOR 150 N. LAKESHORE DRIVE. OCOEE, FLORIDA 34761 PHONE (407) 656-2322 EXT. 142 • FAX (407) 656-7835 MEMORANDUM DATE: July 30, 1998 TO: The Honorable Mayor and Board of City Commissioners FROM: James W. Shira, P.E. // City Engineer/Utiliti s Director SUBJECT: Lake Meadow / Prairie Lake Drainage Basin Study Attached for your review and comment is a draft of the Executive Summary of this report. The full draft report is available in my office if you are interested in looking through it. Representatives from Professional Engineering Consultants, Inc. will be present to discuss this study along with the status of the drainage program in general, at the August 4, 1998 commission meeting. Based on this discussion, any comments that the City Commission has with regard to this report will be incorporated into the executive summary and final report. If you want to discuss this draft summary or any part of the full report with me in advance of the meeting, please do not hesitate to call me. Attachment THE PRIDE OF WEST ORANGE PEC PROFESSIONAL ENGINEERING CONSULTANTS, INC. July 29, 1998 OE -260 1-1.0 Mr. James W. Shira, P.E. City Engineer/Utilities Director City of Ocoee 150 North Lakeshore Drive Ocoee, Florida 34761 Re: Prairie Lake/Lake Meadow Drainage Basin Study Work Order No. 11 Dear Jim: Pursuant to the Drainage Workshop scheduled for Tuesday, August 4, 1998, please find enclosed fifteen (15) draft copies of the Executive Summary for the above referenced project. After the August 4th Drainage Workshop, we will finalize the Engineering Report to incorporate comments, if any, from the Mayor and/or City Commissioners. If you have any comments or questions pertaining to the Executive Summary, please do not hesitate to contact me directly at 422-8062, Extension 194. Very truly yours, PROFESS"(ALENGINGCONSULTANTS, INC. David W. Hamstra, P.E. Principal/Stormwater Department Manager DWH/bk.00lp cc: Ken Hooper, PEC (w/enclosure) engineers planners surveyors 200 East Robinson Street • Suite 1560 • Orlando, Florida 32801 • 407/422-8062 • FAX 407/849-9401 Lake Meadow and Prairie Lake Drainage Basin Study Ocoee, Florida Prepared By., PEC/Professional Engineering Consultants, Inc. 200 East Robinson Street, Suite 1560 Orlando, Florida 32801 PECIPROFESSIONAL ENGINEERING CONSULTANTS, INC. engineers planners surveyors suite 1560 Eoia Park Centre 200 East Robinson Street Orlando, Florida 32801 407/422-8062 Lake Meadow/Prairie Lake Drainage Basin Study o o¢000 Executive Summary v ba « eooe � PURPOSE OF STUDY The City of Ocoee initiated/authorized a drainage study of the Lake Meadow and Prairie Lake Drainage Basins, as well as the other fourteen (14) drainage basins within the City of Ocoee, for the purpose of complying with the City's Drainage Sub -Element of the Comprehensive Plan, and more importantly, Rule 9J--5, Florida Administrative Code (F.A.C.). This study will update/amend the City- wide inventory and analysis of drainage facilities, identify system deficiencies based on an established level of service (LOS); and develop a capital improvement program on a basin by basin basis. Specifically, the drainage infrastructure data is used to assess the performance of the existing drainage systems in response to various rainfall events, thus establishing levels of service for each drainage basin. Deficiencies in meeting the established levels of service are identified, along with capital improvements which are necessary to bring each basin's performance into compliance with the City of Ocoee's Comprehensive Plan. STUDY AREA The Lake Meadow and Prairie Lake Drainage Basins encompass approximately 1,800 acres, or roughly 2.81 square miles, of northeastern Ocoee and unincorporated Orange County within Sections 3, 4, 5, 8, 9, and 10 of Township 22 South, Range 28 East. Of the total drainage area, the Lake Meadow Basin comprises approximately 1,132 acres, while the Prairie Lake Basin comprises approximately 668 acres. These basins are identified as Basins "02" and "03" respectively, within the City of Ocoee's Comprehensive Plan (Drainage Sub -Element). The general limits of the Lake Meadow Drainage Basin are Ocoee-Clarcona Road to the north, Clarke Road to the east, and A.D. Mims Road and Wurst Road to the south. To the west, the basin extends to the Forest Lake Golf Club, Angola Street, and Peters Avenue. Approximately forty-one (4 1) percent of the area within these bounds is developed, mostly as single family residences in the western portion of the basin. Because much of the development is older, the primary drainage conveyance systems are roadway cross culverts, ditches and storm sewers which convey runoff directly to Lake Meadow. In the newer developments such as the Amber Ridge Subdivision, stormwater management ponds provide water quality treatment and peak rate attenuation prior to PEC/PROFESSIONAL ENGINEERING CONSULTANTS OE-260.EXS Lake Meadow/Prairie Lake Drainage Basin Study Executive Summary July 29, 1998 Page ES -2 discharging to the lake. The areas which remain undeveloped are located in the northwest portion of the basin and immediately adjacent to Lake Meadow. The Prairie Lake Drainage Basin is located adjacent to Lake Meadow, to the east of Clarke Road. The basin is bounded by Ocoee-Clarcona Road and the Sawmill Subdivision to the north, Apopka Vineland Road and the Florida Central Railroad to the east, and A.D. Mims Road to the south. Portions of the Spring Lake Subdivision south of A.D. Mims Road have also been included in the Basin, because runoff will discharge to Prairie Lake should the 100 -year retention ponds in this development overtop. Development within the Prairie Lake Drainage Basin accounts for approximately forty-five (45) percent of the area, nearly all of which consists of single family residential subdivisions served by stormwater management ponds. Most of the areas which remain undeveloped lie immediately to the north and south of the lake within the Prairie Lakes P. U. D. Both Lake Meadow and Prairie Lake are considered land locked because the lakes have no positive outfall to a riverine system. Nor does either lake have a drainage well. The only possible discharge is between the lakes via a high level overflow under Clarke Road. Thus, when considered together, the only components of discharge from the lakes are evapotranspiration and vertical leakance to the aquifer. STUDY APPROACH In order to assess the function of the drainage features within the Lake Meadow and Prairie Lake Drainage Basins, the hydrology and hydraulics of the existing systems were modeled using state of the art computer analysis techniques. Extensive field work was performed to define the limits of the watershed to determine the key drainage features to be included in the computer modeling. The most current information was used to define land uses, initial water elevations, flood storage, and drainage structures. Sources included aerial maps, topographic maps, lake level records, parcel maps, construction plans, and drainage calculations provided by the City of Ocoee, Orange County, and the St. Johns River Water Management District. Where information could not be obtained otherwise, survey was performed. Ultimately, a comprehensive computer model of the study area was developed using the assimilated data. Multiple simulations were executed to assess the performance of the existing systems under a variety of conditions. Based upon the analyses performed, anticipated peak flood elevations were determined. The analyses were also used to uncover problem areas within the drainage basins. Several additional deficiencies were discovered during the field work phase of the project. The computer model was then utilized to evaluate possible solutions to alleviate these problems. PECJPROFESSIONAL ENGINEERING CONSULTANTS OE-260.DCS Lake Meadow / Prairie Lake Drainage Basin Study Executive Summary July 29, 1998 Page ES -3 As a result of the analyses performed for this study, the following improvements are recommended in order to address flood protection, water quality, and localized flooding (refer to Exhibits No. 1 and 2): Flood Protection 1. Construct an outfall system from the railroad to Prairie Lake in order to convey runoff east of the Forest Oaks Subdivision. The outfall system would prevent overtopping of the railroad and eliminate flooding of homes west of the railroad (approximate cost is $305, 000.00). 2. Construct a high level outfall system from the southwest pond within the Sawmill Subdivision to Prairie Lake in order to prevent flooding of homes during extreme conditions (approximate cost is $250, 000.00). Water Quality 1. Construct a sedimentation baffle box at the end of Nicole Boulevard (approximate cost is $50,000.00). Currently, approximately 122.5 acres discharge directly to an existing pond which was constructed by berming off a portion of Lake Meadow. Consequently, when the water level is high, the berm separating the pond from Lake Meadow is submerged and runoff from the 122.5 acres discharges directly into the lake. 2. Construct three (3) sediment control devices (leaf traps) within the Forest Oaks stormwater pond (approximate cost is $5,000.00). During high water levels, the berm separating Prairie Lake and the stormwater pond associated with the Forest Oaks Subdivision is submerged and the pond provides no water quality or quantity volume. Therefore, the sediment control devices are recommended to reduce the pollutant loading to Prairie Lake when the existing pond is submerged. 3. Retrofit the Amber Ridge stormwater pond as a wet detention facility in order to provide water quality treatment prior to discharging to Lake Meadow. The ownership of the pond is currently in dispute, therefore, until ownership has been resolved, the City is not responsible for retrofitting a private system. PEC/PROFESSIONAL ENGINEERING CONSULTANTS OE-260.EXS Lake Meadow/ Prairie Lake Drainage Basin Study Executive Summary July 29, 1998 Page ES -4 Localized Flooding Construct three (3) culverts under Clarcona-Ocoee Road at Lauren Beth Avenue, Ingram Road, and approximately 1, 000 feet east of Adair Street. Currently, the realignment of Clarcona-Ocoee Road is being evaluated between Hiawassee Road and the proposed Western Beltway. Therefore, it is recommended that these culverts be provided when improvements are made to the roadway. 2. Upgrade existing culverts and raise the profile of Lauren Beth Avenue and a downstream private driveway located south of Clarcona-Ocoee Road and north of Nicole Boulevard. The improvements are recommended in order to convey anticipated flows and prevent overtopping of Lauren Beth Avenue. Currently the conveyance system is located in unincorporated Orange County. Therefore, it is not recommended that the City of Ocoee expend its resources to improve drainage conditions in this area. 3. Retrofit the existing stormwater pond located west of Clarke Road and south of A.D. Mims Road within the Reflections Subdivision. Due to standing water which is prevalent in the existing pond, peak flood stages could flood the intersection of A.D. Mims Road and Clarke Road. Therefore, it is recommended that the City of Ocoee and/or the St Johns River Water Management District coordinate with the developer to correct this situation at their cost. PEC/PROFESSIONAL ENGINEERING CONSULTANTS OE-260.EXS a ICONSTRUCr AN EXH/B/T No,2 EY ?YNO FACKLT/ES MAP PRALME LAAFKAKE MEADOW ONALNAOEEASM STUDY OCOEE FLOE/OA PEC/PROFESSIONAL ENO/NEER/NO CONSOL rAM$ MQ i GIwOiXIACAOILi`-IBBIQ`JBO-1 Br/]B/SB JA -3 LEGEND P aH — ary LMrs ® SR WARR M E sm mA r D� Lnsrnn awmiz smucnime o--� La�rW,w Acer - o— Q]r)AIC MANAXE ►----� NICME ONSIRUCI F----( NRIPE IlfEl --w NRAPE MMYNYE ® M"LLAhD EXH/B/T No,2 EY ?YNO FACKLT/ES MAP PRALME LAAFKAKE MEADOW ONALNAOEEASM STUDY OCOEE FLOE/OA PEC/PROFESSIONAL ENO/NEER/NO CONSOL rAM$ MQ i GIwOiXIACAOILi`-IBBIQ`JBO-1 Br/]B/SB JA -3 6 . d.44 A�l � JPC C r /1?k - _� City of Ocoee August 4, 1998 CMeeting Prairie Lake Recommended Improvements D Forest Oaks Subdivision - Construct an Outfall System ($305,000) D Sawmill Subdivision - Construct Emergency Overflow System for the Southwest Pond ($250,000) D Forest Oaks Subdivision - Sediment Control Devices ($5,000) D Reflections Subdivision Retrofit Pond (by others) Lake Meadow Basin Recommended Improvements D Nicole Boulevard Baffle Box ($50,000) D Retrofit the Amber Ridge Subdivision Pond (by others) D Clarcona-Ocoee Road Culverts at Lauren Beth Avenue and Ingram Road (costs incurred with future roadway improvements