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HomeMy WebLinkAboutDocumentation_Stormwater_Tab 05_04/29/1999 Village of Tegnesta Country Cinb Community Drainage Study April 1998 prepared bp: Cherie Sons, P.E. 4070 Okeechobee .Blvd., Suite ZZl West Pslm Basch, Florida 33409 V -.: 4 Table of Contents I. Introduction ...................................................................................I A. Scope ............................................_....................................I B. Background .........................................................................I II. Existing Conditions ....................................._................................... 2 A. General ............................................-•---............................. 2 B. Topography ......................................................................... 2 C. Geology ..............................................................................3 D. Land Use .................. ........................................................... 4 E. Existing Drainage :.................................................................. 5 F. Drainage Areas .............................................•--......................5 G. Problem Areas .......................................................................6 H_ Level of Service Standacds ........................................................ 6 III. Water Management Analysis .---..:: ...........:............................................7 A. Model Input and Assumptions ...........................•----._....:.---•--:......7 .. B. Calibration .......................................................... ...8 C. Findings ........................:.....................................................8 IV. Drainage System Evaiuations ...............................................................10 A. Drainage Alternatives .................................................:::°:.......... 10 B. Proposed Improvements ........................................................... 17 C. Preliminary Cost Estimates ...................................................:.... 19 V. Recommendations ............................................................................ ZO i Llst of Tables Table 1 SFWMD Soil Storage Valves for Coastal Soils ........................ 4 Table 2 Permitted Water Control Structures ...................................... S Table 3 ~ Rainfall Depths for the Village of Tequesta ............................. 7 Table 4 Proposed Pipe Replacements ............................................. 11 Table 5 Proposed Water Control Structures ...................................... 12 Table6 Summary of-Existing and Proposed Stages ............................ 18 Table 7 Preliminary Storm Drainage Cost Estimates ............................ 19 Ljst of Ea6ibits Exhibit A Location Map Exhibit B Drainage System I Exln'bit C Drainage System II Exhibit D Proposed Typical Roadway. Cma~-Section Appendix A Water Management for Drainage System I Appendix B Water t Analysis for Syst+ern II n I. Introduction A. Scope In February 1995, the Village of Tequesta authorized an engineering analysis of two drainage systems within the Villa's Country Club Community (refer to Exhibit A far Location Map). The purpose of the analysis was to determine what the existing Levels of Service are and what improvements would be neocessary to provide Levels of Service oonsistEnt with that adopted by the Village. The scope ai' the study included the following • identification of existing drainage systems and outfalls • id~tif cado~n ~' known problem areas • a review of topography, land use, and soils data • a review of the existing typical rooedway cross-secti~ • voordination with South I~7arida Water Management District (SF~vNID) • a r+sview ©€ SFWMD Permit Fdes • a review of existing drainage conditions and development of drainage b~in4 and sub- • a discusrs~ of Level of Service Standards • computer modeling of two existing drai~ge systems • investigation of alternative s~olutioas • r+eaommerrdations for improvements • development of preliminary cost estimates for proposed improvements B . Background In .iuly 1979, SFWMD issued Surface Water Management Permit No: 50-ODfi8e2-S to the Village of Tequesta for "oonstrudion and operation of a water management system to serve 355 ages of residential lands' : The proposed drainage improvements included the constirttictiare of three additional outfalls rA the Northwest Fork of the Loxahaticlme River as well as expansion oI' 1 the existing golfcourse ponds, the addition of new storm mowers to improve road drainage, and corLStrvction of water control structures to provide water quality and limit discharges. The permitted improveutents are indicmted on Gee 8E Jenson, Inc. construction drawings dated May 1979 field observations indicate that the prtiposed drainage facilities have been ducted and appear to be in substantial conformmance with the cortsttuc-tion drawings. . In resp~se to the drarirrage problems occurring within the Village's Coem4ry Club Community, this study was androrized b address facility needs to reduce flooding. The location of the study area is shown in Fxhibgt A. The study area indud~s two major drainage systems which discharge to tine Northwest Fork of the L~ahatchee River Draiinage System I consists of catch basins and stormwater pipe and three gnlfcourx ponds (Numbers 2, 5, and ~ which discharge through a water control structure too; C3utfall B. Drainage System II o~msisfs of crotch basies and stormwater pipe which directs discharge to a golfcourse pond (Ntnnber 12) and through a water control strvctrrre ~ Outfall E Both systems were desigrmd and permitted m 1979 II. Esaisting Conditions A . General Drainage System I caanprises an area of approximately 113 acres and includes sections of Country Club Drive, Fairway North, Fairway East and Fairway West, approximately 49 acres of golfcourse, Bunker Place, and sections of Golf View and River Drive. Drainage System II comprises an area of approximatiely SO acres and indudes sediae$ aI' Cotuttry Club Drive, Yacht Club Place, Fairview East and Fairview West, D Pbrtat Drive, approximately 16 acres of go[fcourse, and actions of Golf View Drive and River Drive. The study area boundaries are shown oo Fxhbit A. B. Topography Detailed topographic maps of the Village (inducting road elevations and furished float 2 ' elevations) were not available. Ther~'ore, the topography of the study area wag esoimated using the following. • May 1979 oonstructio® drawings "Country Qub Community Drainage Improvements" Pml~ by Gee & Jenson • June 1979 construction drawings "Country Club Drive Resurfacing and Drai~ge Improvements" prepared by Gee & ]enson • SFWMD Pr[mit information • U.S.G.S. (United States Geological Survey) quadrangle maps • Field ob®erwations and measurements (i.e:, spat-checking of selected key elevations) A review aj' the topography based on the above sources indicates that developed site elevations within the residential area of tlm study area vary from approximately 6 Ft NGVD ~ approximately 9 5 F~. NGVD and the average elevation of the golfcorrrse appears to be 8 Ft: NGVD. In addition to determining drainage drvides, topography is irz~tive ~ the storage capacity of a basin. A steep watershed wiD generally indicate a rapid rye of nmoff with little storage, whereas relatively Bat areas such as the study area are salrject ~ cx~nsiderable and lower rat~eg of Bow. Within the study area, natural ground elevations tend to slope from the gdfoourae towards the LoxahaUclme River. C. Geology A United States Department of Agricultrme (USDA) Soil Conservation Service (SCS) soils survey for Palm Beach Canty, Florida was used to identify the soils in the study-area. InfrlVation capacity and the ability of underground strata to trait or hdd grauidwater are affecxed by such soils properties as permeability;depth to ciaypan, r1ock ar other layers that influence the race of water movement; and depth to the wader tab1G Thus, soil properties influence the generation of runoff frao rainfall and must be considered in methods of runoff estimation. 3 ' According to the SCS soils survey, the study area consists of St Lucie sands. St Lucie sands are typical for areas located near coastal ridges and consist of deep layers of sand with excelkent percolation rates. Therefore, in determining soil storage, SFWIvID values for coastal soils (wl~ch show lower runoff potential) were used. Typically, coastal storage values show lower runoff potential and moderate to high infiltration rates favorable for drainage desiga The SFWMD sal storage values for coastal soils are given below: Depth to Water Table Cumulative Water Storage Compacted Water Storage (Ft) (Inches) (Inches) 1 0.6 0.5 2 2.5 1.9 3 6.6 5.0 4 10.9 8.2 In developed areas, soil storage values are reduced by ZS% to -allow for compaction. The values in fire third column represent the estimated amormt of water which raa be st+urad under pervious areas after development D. Lsnd Use The study area is entirely developed and consists of two land uses: single family residential and recreational (golfcozrrse). A RIDI aerial photograph was obtained a~ used to furrber identify the laml use cha~rac~ristics of the study areae including percentages of impervious area, paves area and building Runoff is a funcxion of the Iand use istics of the area. iJrbani~tion usually results in an accelerated removal of stormwatar with corresponding increases in the volume and peak of runoff. This is due primarily to an increase in impervious surfaces such as roads, sidewalks, driveways, parking lots at~t buildings. An increase in impervious surfaces decreases the 4 opportunity for infiltration and increases the runoff potential of an area. E. Existing Drainage T'he natural drainage of the Village (primarily overland flow) is augmented by sta~m sewers. The two existing storm sewer systems addre~ed in this study were deigned to dired• runoff tD golfc~arrse ponds with water oontr+ol stirncdu~es to provide detention for water quality enhancement and rest<id nmoff' through the outfalls ~ the I~a~lmtchee River. The permitted water control shtuxRUes are described in Table 2 below. Bleeder Tap of Weir Crest Weir Bleeder Invert 3gvc~ure F~evatian Dimensions Elevation (Ft NGVD] (F2 NGVD) (Feet) (Inches) (Ft. NGVD] D~ ge 6.0 5.5 2.0 4"high x S"wide 3.5 g recrangrrlar 5.0 4.5 2.0 4'7righ x 8'"wid$ 3.~ S rectangular Fach~ water ccntr~ol s consists of a d inch high by 8 i~ wide'ne~gnlar- arifice witfi our invert elevation of 3.5 Ft NGVD and a two foot wide weir with a weir cxe$E elevation of 4S Ft NGVD and 5.5 Ft. NGVD far Drainage System I and II respectively. Downstream of the water control structtmes, stormwater runoff is collected in etch basins and conveyed through • stormwater pipes directly into the Loaahrtl~elree River without any pmvisia~ns for water qualety or water conservation Field observatiaes iadicatted that the water oontr~ol structtues are not operating as permitted. As a result, the golfcourse ponds are maintaining water elevations as much as a foot higher than the permitted control elevation, resulting in lost surface storage within the systems. F. Drainage Areas The boundaries of the drainage areas f~ each of the two drainage systems within the study Gy J ' ` 'area are identifred ~ Exhibits B and G The boundaries were delineated based on a review of available c~rrswction drawings for existing drainage systems throughout the Village, SFWIVID Plermit Files, and field obrorvatio~ns. Once drainage basins were developed, they were further divided into sub-basins in order t+~ evaluate the varies aomporrents of tl~ existing drainage G . Problem Areas The areas within the study area which were observed b have ~ raver revere drainage pao6lems are located upstream of the golfcourse and irxdttde secxions of Counhy Club Drive, Fairway North, Fairway l ast a~ Fairway Blest within Draimge System I and sectiions of Fairview Fast and Fairview West. Yacht Chrb Plane arm Country Club Drive within Drainage System IL The most severe drainage problems exist within areas where finished floor elevations are low relative- m the road (i.e., less than 1S feet above the adjacent road cx+nvva elevations). Field mnents in~cated that there. ar+e homes within Draimge II thy. are only approximately Q5 feet above the adjacent roadway cxawn H. Live! of Service Standards . The Cir+owth Ivtanagement Act (I9~ and supporting regutatiars (Ch. 9.~SF A.C.) required that local governments-adopt Levels of Service for draina~ faalities in their onmprehensive per. The Village of Tequesta has adopted a 25 year 24 hart Level of Servive Standard for drainage facilities within the ViUag~ This is consistent with what marry local governments have adopted for mower develts and exceeds the Level of Service Standards set for rider, existing deve.Iopn~ts which would r~equirve retrofitting to mew current water management standards. Often with retrnlitting land availability and topography are limiting farxars along with economic eonsideratioa4. The design of a drainage system with mflic~ient rapacity Do accommodate the most severe 6 rainfall expected cannot generally be economically justified because d~ cod of such a system would be prohibitive. Therefae, it is necessary to select a design frequency which will provide adequate flood protection without resulting in excessive cost. As practical and ecx~ic~I criteria, rm~ny municipalities have adopted a Level of Service Standard equivalent to a 5 year 24 how slam event or a 10 year 24 hour storm event for roadways and a 100 year TL hour worm event for minimum finished floor elevation. A five year return frequency slam is a storm with a rainfall depth which would not be expected on an average move dran area in a five year period. (It must be noted theta return frequency period is based on pest records and historical averages a~ tune is ~ guazantee that two or more frve year storms will not occur withia any five yeru- period.) Obviously, a ten year return frequency storm will occw Less frequency; however, the rainfall depth wilt be resulting in a mere cosdy drainage system. SFWNID rainfall maps were used to determine the rainfaII depdts for various stcxm eveat~. _ For the Village of Tequesta, the depth of rainfall fa• spe~afic return freq and storm are as follows: Return ~w~ and Storm Duration Rainfall Depth (Inches} 3 year 24 hour 5.3 S year Z4 hour 6.5 10 year 24 how 7.5 25 year 24 hour 9.0 100 year 72 how 26.3 Ta6ie 3, Rsiofsll Depths for the iliage of Tequesta III. Wattr Management Analysis A . Model Input and Assumptions The study area. arcs modeled using CHAN for Windows (Version 2). This computer 7 program generates stmrnwater runoff tiydrographs far sub-basins and perroms hydrodynarrue routings of that runoff through a surface water management system comprised of Lakes, ponds, channels, and drainage structtmes Drainage Systems I and II were modeled as closed oondtdt or piped systems discharging into golfeourse ponds which ultimately disdearge through water co~rol structures to the Laurahatchee River. The tailwater conditions were based an an tiara of mean high tide at 2.4 Ft. NGVD fog the Lonahaaehee River. Hydrologic and hydraulic input parameters were determined using the best ird'ormation available including a combination of permit iofocmation, eoasGrerction d[awings, fell obsavatia~ns and moments, and U S.G.S. quadraagte maps. Drainage facilities modeled included ponds, culverts, and water control stneetu~es (as drop strttetures). B . Cal~bratioa Once the computer models were developed, the models of the two existing systems were calibrated using observed and 3FVVND7 rainfall:,datafar~he Oetcher 1995 storm event. SF'VVIvm rainfall data indicated a ?2 hour rainfall depth of approximately 1~2 inches. (winch- eocceeds the 100 year 72 Dour rainfall amarnt for the Village of Tequesta~. DuriAg the C>ctober 1995 storm event; within Drainage System II espexieneed flooding and there was significant flooding of the roadways throughout the study area. Water elevations as high as two to three feet over the roadways were reported. The results ~ the caiibtatiort simulation with a'T2 hour rainfall of 18.2 inches and a tailwater elevatrion of 2.4 F~. NGVD were consistent with the observed stages After the models of the exiling drainage systems were suooessfully calibrated, the models were used to identify problems and investigate the impacts of proposed drainage improvements. C. Fiadiogs Based on a review of the Redi aerial photograph aid field observations, it appears that the 8 existing golfcourse ponds (with the exception of Number 2) were constructed in acoordanoe with the May 1979 construction drawings and SFW1vID Surface water Management Permit Golf'course Pbnd Number 2 has been modified with the elimination of the swale area ark expansion of the pond. Although the water contra structures appear to have been constructed according to the permitted drawings, site reviews indicate that they have been adjusted and/or modfied. The result is a reduction in deteatti~ for wader quality treatment arm less surface storage available for flood protection. For the purposes of this analysis, it was assumed that the galfcornse ponds (except for Number Z) and watts cxmtr~ol structures were constructed and are operated in compliance with the SFWIVID Permit The modificahions to (iolfcourse Pond Number 2 are reflected in the analysis. when the Level of Service Standard adopted by the Village (a 25 year 24 hour storm event with 9 0 incites of rainfall) was used to analyze the two existing drainage systems the results indeca6ed that there would be ponding widr r+datively long duration (greatier than Z4 hours) and rmtidways would not be accessible. Drainage S~rsterns f and II ;wane furtherevahrated using a 3 year 2A~ hour storm event with 53 irrehes of rainfall and it was determined -that the eAis6ng drainage systems provide a Level of Service Standard equivalent to less than a 3 year 24 hour storm event. During a 3 yeas 24 hour storm event, peak stages exceeded die mitimum road elevations by 0.1 feet for Drainage System I a~ 0.2 feet for Drainage System IL A major reason for the roadway flooding is a lack of moorage facilities, specifically a lack of storage below the roadways within each of the drainage systems_ With most of the golfc:ourse graded at elevatiions as high or higher than finished floor elevations, the golf~urse ponds offer the only opportunity for the storage of stormwater ninoff within the golfcourse and when flaw nrttoff is S than they can acoo~rnmodate, the roads become flooded. Forwnately, most of the buildings within the study area are much higher than the roadways so the flooding of buildings is less frequent than the flooding of roadways and is limited to those homes that have low finished floor elevations relative to the roadway. 9 In order to provide better flood protection far the roads and buildings with !ow finished floor elevatiam, either discharges to the Lo~af~e River must be increased or additions! surface storage must be provided. Due to the cwrent r+egutstory environment, inctased discharges m the Loxahatd~ee River are discouraged and therefore, sources of additiarial surface storage must fast be euplored. For the Vt~tlage of Tequesta. Country Club Community, land acquisition is riot possible and increasing the size ai' the golfeourse ponds is not practice! ar economicauy feasible. As a resarlt, the use of roadside swaies as dry retention areas is proposed. Drainage improvements for Tequesta Drive and Seabrook Road were re~tly permitted by SFWlI~ID and constructed by the Village and appears m be a successful application of the use of roadside swales as dry retention areas. To increase the conveyance of the drainage sy~ns and improve flood won within the study area it will be neces4ary ~ replace the stormwater pipes between each of the water control structures and correspondmg outfalls m the L~tahatcd<ee River. Urxlet exrsting conditions, the ~. pipes are coa>iotleng ~ to a gr~eatet degree than he water carn4nal ~. I V. Drainage System Evaluations A . Drainage Alternatives The following drainage alternatives were evaluated to determine the effect the propo®ed improvements would have an flood protecxion: 1. storm sewer pipe improvements 2. modifrcations to the water control (indudiug provisions for emergency discharges) 3. eapaagion of the golfoourse pis (includueg dredging 4. roadside swales for local disposal of stormwater by infiltration 5. diversion of flow A 25 year Z4 hour storm event (9 0 inches of rainfall) was used ~ evaluate the flood 10 protec0ion bents associated witL the alternative drainage improvements. Alt6~gh flood pto6octian was consider+od to be the primary objective, oansideratian must also be given to water conservation (especaaUy in an area sceh as this where saltwater intrusion is a concern) and water Quality due to State regulatory reQuirements. Thus, within this rE:gularor3r framework, each of the drainage alternatives is further dexribed below. 1. Stoma Sewer Pine Imnro_vg~e~gt TLe proposed storm sewer pipe improvements are given in Table 4 and can be seen in l~chibits B and G Storm sewer pipes within Drainage Systems I and II for which imptvvem~ts are not t~eoommarded were deemed m be satisfactory based on ~ i~'orasatian available far this study. System I . ~fram ~oratian to Iaen (#'e ~ Pi siae and type Fi type I Water contr+d soructwe Qalf View 350 2~~ cmp 42" mP I Golf View Golf View 60 24" cmp ~" rcp I Gdf View Raver Drive 250 2A'~ cmp 42" mP I River Drive River Drive 40 30" mP 42" rep I River Drive IAxahatchee River 180 30" r+cp 42" r+cp I Fairway West Golfoourse Pond I70 Z4" cmP ~" mP I Fairway West Fairway West 30 24" cmp 36" mP II Water eoretrol struchue Golf View 150 2A~" cmp 42" rcp II Golf View Gdf View 35 24" t+cp 42" mP II Golf View River Drive 270 ?A" mP AZ" r+cp II River Drive River Drive »0 30" r+ep 42" ricp II Rivet Drive Lrnsahatchee River 180 36" nrp 42" mP II Fairview West Golfcoutse Pbnd I50 2~' c:mp 42" nrp II Fairview West Fairview West 50 ?~" cmp 36' nrp II Fairview East Fairview West 250 I8" cxnp 36" mP II II ~~Pbrtal Drive II Pbrtal Drive 120 unknown 30" rcp II D Pbrta! Drive Fairview West 120 wnknown 30" mP sb a 4. pose Pe ep ements . 11 ' One problem with the proposed Pipe rr~laoements is that Tripes are located within ten feet wide drainage easement4. Twenty feet wide menage its are normally ~eaommended as a miamum far ease of construction shaild rep~[aeement be necessary. In addition, the drainage ea~ernents ane mostly located between eatpen~ve homes and ape replacements would e~srupt exiting lands ping and irrigation. 2. Modif~eatians to the Rater Control 5tructnrrs ( lud ~ nrovislions for sier~ene~ d, i='~,~1 The proposed dimensions and elevations of the bleeders and wars and ~ of the sorrrctures are given in Table 5. Bleeder Top of Weir Crest Weir Bleeder Invert Structure IIevatian Length Dimensions Flevatian (Ft. NGVD}_ (Ft NGVD) (Feet) (Inches) (f~ NGVD) 5.5 Not Not 4'~ugh x t3"wide 3.5 APPh~ Applicable mar 5.0 4.5 2.0 4'7n~~ 8'~wide 3.3 l~~ The proposed ~difrcatio~ are to the water vonttol structrue of Drainage ~ystern i*and include, as indicated by Table 5, etintination of the 2 feet wide weir with the tz~ of the stnrcdrne lowered from elevation 6.0 Ft. NGVD to SS Ft NGVD No ntadific~o~ are proposed rD the bleeder and war of the water c:©ntr~ot sp~c~e of Drainage System II. Other proposed modif cations ~ the water c~ontid sttucdues are: - r~eplaaement of outfall pipes with larger pipes (see pipe teplaoements) - replavement of existing with Type E inlets and sloe, grates (constructed so tlr~t the entire perimeter of the inlet is ~ and available for flow o~ die structrue) to accorr>rrtodate the larger outfall Tripes and allow for greater discharges during major storm events 12 - lower strncdne bottoms to aooommodate lower invert elevations of outfall pipes operation ~' the water oontnd structures as permitted by SFWMD t4 maintain a oontroi elevation of 3.5 Ft NGVD is the golfvowse ponds provisions for emergency discharges (e.g., screw gates) The Proposed modifications outlined above in conjunction with the proposed r+oad~de swales will result in an increase in the eaistiag and permitted detention for water quality as well as ao inct+ease in the peak discharge. It is important to note ihatalthough the peak discharge increases, the volume of nmotl' discharged to the Loxahatchee River will decmase as a result of liar in~sed detention and proposed retentia~ To provide additional flood r+eGef for the area operable structures are proposed which wil! allow the Village to lower the water elevations within the golfoourse ponds in a~icipation of and following major storm events. As a result of the CkKober 1995 storm everN, SFWMD has initiated a process for permitting emergency facilities. An operating sclarclule must be developed and ~. approved by SFWNID prior ~ implementation.. 3. ~ ion of the .nltfronrse Pnn ~ In the Past, go~fcourses in South Florida were often designed with lower elevations than the starotmding residential areas io coder to serve as stormwater storage oleos. Since the Village of Tequesta gdfcoutse is mostly higher thaw the sentounding residential areas aad a lack of storage facilities is a major reason for tlm flooding of roadways, expanding the golfoourse ponds would be most advaa a~ viewed very favorably by SFWIVID Typically, with rarw developments, water management areas are approJdmately I0~ of rho total project area. Unfortunately, the goifootase is Privately owned and th~'ore the eapan.~ion of the golfi~outse Ponds would be eoonomic~lly unfeasible. Due to the excessive ooh of implementing this alternative, further evaluation was deemed un~oessary. In the event that, over the years, siltation has ocacurred within the golfcourse ponds, i3 ' ~ dredging may be + to restore original design specifications. Although dredging will not increase the storage ar conveyance of stormwater through the ponds, dredging may be requrred, however, to accommodate the invert elevations of the proposod pipes. If the bottom of the ponds are above the invert elevations of the incoming pipes then the ponds will need to be dredged so that inflows cad outflows will not be restricted. . t i ~ ~ ,~ _ i i~ 1 :: ~~~~~ it i~ ~ i L ' ~ _1 1 _1~ 1t_ ~ Tire traditional method of dispo~ng of stormwater in an urban area was w drain the stormwater away from where it fell as quickly as possible Clutters and storm sewers were normally proposed to convey the r[rnofl' to the nearest cast or lake. In recent years, in response Co emironmentat c~oncernss, the rapid conveyance of stormwater down.stream is discouraged and consideration must be given ~ water quality edrancernent and water ooa~ervauon_ Water quality requirements are ~t well defined fair existing built-up azeas. Although the ~, State has set goals for ration and/ordetention,-these goals may not be acltievable for an existing urban area such as-the Village of Tequesta. However, since new outfalls (or replacement of existing outfalls with larger pipes) are poposed, the Village will be tiequired tc> meet orient water quality requirements to the maximum extent practicable. Therefore, infiltration is piopo®od Do conarol s6ormwater from individual residential lots. Dry ietentianareasare- to be con within the road right-af-ways tLroughout fire study area as indicated an the propo®ed typical ra®daraY cross-scion shown in F~chibit D Raised inlets will act as blocks in order m nnaaimize the amount of retention provided The advantages a~f local disposal of stormwater throw infrltratian induder 1 _ recharge of groundwater 2. reduction of downstream flows 3. r+eductio® of pollu~nts transported iD the Loxahatchee Rives 4. wilt help to alleviate roadway flooding 14 k The disadvantages ~ local disposal of Stormwat.er thtough mfihratio® Induce 1. increased marntena>rce 2. site specific design is necessary 3. if not designed carefully, infiitraoion systems may not word ark if ~ maintained, fla=y become inoperatiive 4. wet site conditions 5. public awareness campaigns are af'ten necessary due to public opposition 6. close supervision during construction is required do ensure proper 7, high construction costs in addition to maintenance costs The proposed dry retention auras are shallow (O 5 feet below the_edge ~' pavement) which shored minimize wet ate oandrtioa4 especially if the underlying sails are: porous. Although soils pility ~ porosity toasts were not available far flue study, the SCS Soil Survey indicates drat the=soils in the study area are strita6le for intr~traeiors. Still, in aurder to allow stormwater m infzltratie into. th+e grormd, there will be temporary ponding of runoff within the roadside swales. The duration of ponding may be as long as 2A to 36 bozos depending on specific soil conditiaos (indurding soil permeability and porosity and depth to the water tablek SFWtVII) approval of the proposed dry retention will require proof of excellent soil percolation rates (eg., coastal ridge sarZds) or an operatia~ entity which specifrcalty reserves fzmds for operation, maiutcnance, and replacement. 5. D~-er~an of Flow As art alterna4ive mearns of improving the hood protection far Drainage System Q, a potential diversion of Bow was investigated. This alternative indwdes design and constrtr~n of a piped sy~ern to direct sicxmwater runoff fimn the ru~idential area within 3nb-basin B 1 of Drainage System II south to Tegtresta Drive and east to an existing Palm Beach Cozmty ditch that outfalls via 15 a 36 inch r+cp to the Noah Fork of tine Loaahaticl~e River. The existing ditch currendY P~~~ drainage for Tegeresta Drive, a development immediately north of Tequesta Drive (Bennnda Terrace), and the First ~ Chwch of Tege~ whidt is located immediately south ~' the roadway. This aJtenrative would require approximately 1000 feet of storm sewer pipe ro connect dm sub-basin (which currendy discharges to t ioifcourse Pond Mumber 12) to the ditch. A~uming that die existing ditch (approximately 400 feet targ) will be replaced with pipe, the fdlowing improver~nts would also be required: • Removal of the existing 24 inch cmrp between Fairview wed and t'wlfcourse Pond Number 12. Replacement of die existing pipes between Fairview west and Country Club Drive. • lteplaoement of the ~6 inch rcp that exte~s approximat~eiy 600 feet from the ditch to the Loxahatchee River. To accommodate the runoff from Dr<einatge Syste;n II cad nninimi~e ~ impact on otlu;r devdopments, die minimum pipe size r+equir+ed between the existing pipe at Cotmhy Chi Drive and the North Fork of the LoxabaGchee River is a 4L inch ~ In addition, the existing pipes between Fairview Fast and Countyy Qub Drive wiU need to bE r~eplaoed with a 36 inch r+cp and the existing pipes between Fairview west and Fairview East win need to be with a 3o inch r+cp. Dischazges fi~nm Teq~sta. Drive, Bermuda Terrace, a~ the Fast Presbyterian Church of Tequesta were considered in dm analysis Since app~~dmaiely 1400 feet of raw pipe would be required in ad~tion ro the pipe replaoemems. the cost of the flow diversion w~l be much greet than the proposed improvements to the existing outfan pipes of Drainage S~rstem II. Also; the dversioa of flow to a County ditch would require permittiag by Palm Beach County as well as SFWNID Assuraaoes would have to be gn-en tD both agencies that rro negative imparts to otlurr developments will occur as a result of tilts project If drainage problems already exit in the area, it is unlikely drat such assurartves could 16 be given unless the design ware very conservative (insulting in larger Apes and increased costs). According tv Palm ]peach County, Bermuda Terrace has experienced ~ainage problems in the past Irnm~ing the drainage area by approximately 47 aces wild only compound the existing problems and fudge drainage problems would likely be attribuEed to any modifications b the existing system. Bede of the 6igh~ costs invdved and flu; potential controversy when connecting to an existing system, this alternative is not r~mended for implementation. B . Proposed Improveme®ts As a result of the hychnlogic and hydraulic atfalyses of the proposed clrainag~ alternratives within the study area, the following drainage improvements are proposed: • Cansdtrction of dry retention areas within the right-of-way of pli roads within the study • C:ood op~on and maintenance of proposed intatrati~ arras.. • Operation of the water control struchnies as permitted bgr SFWNID (with the golfoourse ponds maintained at no higher than 3S Ft. NGVD). • Madific~tion of the water c~irol strucarre within Drainage System I, as indicated in Table 5, m reduce upstream stages. • Modification of the water control structures in ceder ~ accommodate the proposed pipe rents and allow far e~ency discharges. • Operation of water control structures ~ allow greater discharges in anticipation of major storm events. Pipe replacements as indicated in Table 4~ Although the storm sewer outfall Co the I~oxahatchee River for Drainage System i cxateady consists of a flap gate az the outlet, reptac~ment of the flap gate is not proposed since thane does not appear to be a problem with high tides (i.e., minimum road devotions are sigmfic~ttly higher than mean high tide). I7 ' A stmm~ry of the impact of the proposed improvements on flood stages is given in the fdloaaing table. Drainage Sub-basin Existing Fainting Proposed Proposed System 3 year 2A~ hour 25 year 2r4 hour 5 year 24 hour 25 year 24 hour (Ft. NGVD) (Ft- NGVD) (Ft- NGVD) (Ft- NGVD) I B I 6.6 ?.9 6.5 7.2 I B2 6.0 7.l 4.5 6.1 I B3 6.0 6.9 4.2 5.8 I B4 4.8 5.8 3.6 5.2 I BS 4.6 5.4 3.3 4.4 II Bl 6.7 7.6 6.5 7.0 II B2 6.2 7. I 5,8 6.4 II B3 6.Z 7.0 5.4 6.2 II B4 5.2 6.3 4.7 5.5 II B6 4.8 - 5.6 4.0 4.6 Table 6. 3emmary of aisting acct Stages The minimum road cent elevations are meted b be 6S F~t rTGVD far Sub-basins B I, B2, B3, B4 a~ BS within Drainage System I and Sub-basin B I within Drainage System II and 7.0 Ft. NGVD for Sr>b~b~ns B2, B3, B4 and. BS within Ihainage System II. The minimum finished floor elevation within Sub-basin B 1 of Drainage Sy~em II is estimated 6u be 7.0 I~. NGW. Therefore, the proposed improvements will result in an iacrease in the Level of Service far roadways from less than a 3 year 24 hour to a 5 year 24 hoar storm event. (A 5 year 24. hour Level of Service is tl~e reooecl minimum standard for r+oadways.) In addition, the 25 year 24 hour stage wr~I be reduced by Q6 feet or more which wilt lower the 25 year 24 hour stage witl>;an Drainage System II ~ the estuomated minimum finished floor elevation of homes within the ~- . 18 C. Preliminary Cost Estimates Preliminary oast estimates for the propa~d storm drainage improvements are smnmariaed in the following table. 19 is a that the swale eaccavation will he completed tyy others. F~orr Drainage System II, pselimiaary ooh estimates are given for two options. Option.l-is for tI~ neoommentled imp~vements indeding replaoemeat of the existing water oo~n~ stticgQe and downstream pipes. Option 2 is for the flow diversion including replacement of the Palm Beach County ditch and downstream P~I~- V . R~eommend!ations The proposed die im~ovements within ilm steely area wilt serve to improve the t overall flood protection of the ama. It is tt'ore reaanmended that the prolx~sed improvements be implemented along with the promotion of good operation and maintenance practioe~ (t'bor operation and maindeaance r~edu~s the hydraulic c~pecitY a~ 1~~ removal efficaea~- of dee drainage faaitities.} The atxn+e PAY cost estimates do not include oar~tvc~an of the road~de sovaies. It • ~ The proposed improvements will require an Enviranmeatal Resour+oe Prermit from SF~1/11~ID Plermits wiU also be regeured from the Deparmaent of Environmeatai ProtecOion, the Army Corps of Engineers, and the U.S. Fish and Wildlife Service. It is ualifcedy that the proposed pipe rents ar wale: coatriol s modific~ons will be permitted by SF~NMD without addres~ng current water quality and quantify criteria. Although SFUNMD r the difficulty this presents for eustiag buu~t-ems areas, the ViUa~ will need to commit to beat mkt practices such as the comtnicao®and mai~enanc:e of ride swa[es as dry retenti~ areas throughout the study area. In additi~ m providing water quality eahartoemeat and water coasarvatian, the proposed swales will serve f4 extend system capaaties Other recommeadatioas for the Village of Tequesta are ~ below: • To adopt a 5 year 24 hour Level of Service as a minimum standard for eacisgag roadways within the Villa. • To impleme~ Option Z rather than Option 2 to improve flood protectiarr within System II. In setting priorities, caasider oasnstruction of ths; roadside swales as a top priority ~ facaGtate the permitting of the other proposed improvements. • After construction of the roadside svvales, priority should be gives m Drainage System II over Drainage System I becaurse of the severity of tha existing drainage problems. 2l EXHIBITS LOCATION MAP Ex1tib~ A yf '~ ~~~ *iw,w ? wow ~1~1~ ~ ~ ~,! t * ~ A A ~ ~t ~ ~y~i ~ ~ w • '`' ,`MM ~! ~ K ~wi w~ y:"~ t~ ~ tl3 ~_. ' . s'' ~ ra` PC11VD ~ 5 ~ ~ ~ ~~ ~~ ~ ~ ~~ ~ Golfcaasse t~ „s~ ~ '[- ~, , :3' weer oo~rd , .~ ~o~-rc ~ Exist 36" ~~.. 3~be~n -~ .~ :,,~ ~~~ ~~ ice: 2T" ,~j '~*. ~ .ro ~ i,u s ~~ r~ ~ ~~ ; ~~ ~ DRAINAGE SYSTEM I Z~ rN 7 a~ r , ~~ - PoNd~ s ~~ ~ PowD ~ 2 ~ ,~ ~ ~ n .~ E ~~ ~~ Ea'i~. ~. a ~ y. POND~16 _ r~ ~ =~~: ~r/T ~ 7 I/ K A !! =T !1 is ~ T ~s ~~`. '•~ • >a, ~ ~ ~ ~ ~i _ TAR R WAY •~ ~ ~~~ ~ ~ r~ ~ ~~ ~ • ~ ` i `.. S ~ w !~ aI h Jr! !G ~ Ilt ~ T~ ~ .3.• !~ r ~!f , V .~ . ~ '!f y' P ~~ ;~ r .~ ,. ,~~s~• ~.~ POND ~ .t~ ~ B:~:ro: RQ~o i~ ~ * D 7 i • ~ ,~,, . ..ja i f~ t .b+~ r ,~ ~~~ ~ ,t~: Galfcosrae s~ ~ ~ r..i ~i'/ ~cn .~ ~- ,- ; W =6 ~~ ~ u w 4 A a r - fi ~ +~ ~ ~2 ~ db WINDWARD ~ . ~ ~ ~ ~ , s3 ~ rj ~ AYE ~ water cmtrnl ~ sip ~~ Tt '" _' -rs sfn,ctar~e '~ dI • ~~ cd, f •_,~ f ~ .PORtA ~ ~ j ~ c~ ca fG3 G*. 3 '' ~ -- ¢ 1~ ~ ~` ~ ar s~ ss ss ~ , ~s ~ ''~ ~p r si ss s. ~ ~ " ~ u~. ra ~ ~It n- ws 1 T ~ ~' r? ~3 I~ IS3 art ; ~ .~ .ice 5 s ~ ~ . ~ . Sub-basin •+~ x ! ~ deagoaftaa ~ '~ _.~ DRAINAGE SYSTEM II • Exhibit C .N ~- SY14II~II,~TRICAL ABOUT 30' 12' g' Ip' ~IiOULD~R PAVEN~NT ~i min. 6" ~ 12576 mex. ~ . 6X. • PROPOSED TYPICAL ROADWAY CBOSS-SECTION far toe Village of Tegnesta Conatry CMb Community Drainage Systems I aad II Exlnb~ D Stos-m~+ater IItility Board ~eetiag Minutes Aprfl 30, 199$ Page 5 Alexander W. Cameron - for 3oseph N. Capretta - for VI . OF VILLAGE OF TBQUESTA COUNTRY CLUB CObflr1UNITY STUDY AND RECOt~~NDED I1~RaVEMENTS . CHERIE 30VA, Councilmember Capretta expressed concern that Tequesta Country Club Homeowners Association was probably not aware that this study had been done since the Country Club would be impacted if the study was implemented. Mayor Schauer suggested they be sent a copy of the report. Ms. Sova explained there were two drainage systems within the community, showed charts of each system, and reviewed each onei Ms. Sova described the systems as overland drainage pipes emptying into the golf course ponds, which were used for water storage, and explained that these ponds were very small in comparison to the area they served. Control structures controlled the 'water flow into the Loxahatchee River. Because of the Loxahatchee River's designation as an outstanding Florida waterway, water quality enhancement was very important for any discharge into the river was very important. Ms. Sova described existing drainage problems, and stated that in system two the houses were built at an elevation lower than the roadway. Existing drainage provided only a 3-year 24-hour level of flood protection. Ms. Sova recommended a minimum standard of a 5-year 24-hour level of protection because the area was built out, and explained that meant roads would flood on an average of once every 5 years. Discussion ensued regarding efforts a couple of years earlier to enlarge one of the golf course ponds and how people did not understand the need. Councilmember Capretta pointed out that Ms. Sova's presentation could have been useful at that time. It was pointed out that Tequesta Country Club had the best drainage of anX golf course around. Improvements recommended by Ms. Sova were: Increasing sYze of storm sewer pipe to get additional discharge to the river and increase storage by increasing The motion was therefore passed and adopted. FYI V. REVIEW DRAIlIAGE P.S. Storm~+ater IItility Board xeetiag Miautes April 30, 1998 Page 6 the size of the golf course storage ponds. Roadside swales in combination with pipe size increased to 42" was recommended. By using swales, water quality would be improved and the volume to the river would be decreased, but would be a quicker process with water standing for less time. Councilmember Cameron commented the difference in area of a 30" to a 42" pipe was almost twice, which effectively doubled the area to carry water. Mr. Oslund commented 90$ of pollutants are carried in the first one inch of rain, and by diverting that into a Swale one would eliminate 90$ of pollutants discharging from the system. Ms. Sova recommended opening the control structures to increase flow to the river. Provisions for emergency operations were discussed. Ms. Sova commented that the community would be allowed to control their control structures to lower the water before a storm so that additional storage would be available. .Dredging the golf course ponds was recommended to remove silted material in the pipes. Ms. SQVa commented ,.that dredging would be a plus to remove pollutants in the silt which would be a plus when requesting permitting. Recommendation far 20' drainage easements over the 10' easements existing was discussed. .Village Manager Bradford pointed out that in a normal circumstance setbacks allowed only 20' between the homes in Tequesta Country Club. Mr. Sova stated she was very impressed with the Village's Swale program which would enhance water quality. An option for drainage system two was to add additional pipe from existing drainage at Country Club Drive south to Tequesta Drive and continue east, connect to an existing ditch, and discharge to the River. The ditch was recommended to be replaced with pipe: Ms. Sova explained that the first proposed improvement was construction of the roadside swales, and she believed none of the other improvements would be permitted without the swales. Swale maintenance would be very important. Ms. Sova commented that the water control structures on the golf course were not configured according to their permitting, since the sliding plate had been turned upside down, which caused water in the ponds to be maintained as much as a foot higher than it should be, so that a foot of storage was lost. Discussion ensued. Village Manager 3t©rmwater IItility Board Meeting M~.autea Agril 30, 1998 Page 7 Bradford pointed out that it was not Tequesta's staff who reversed the plates, and the importance of stressing to the, golf course maintenance personnel that they must not touch the control structures. Councilmember Capretta pointed out that the plates should. be reversed immediately to lower the water level in the ponds in May,• June, July which was flood season. Ms. Sova recommended placing a gauge in each pond to measure the level. Village Manager Bradford reported that within 48 hours of landfall of a predicted storm the Village lowered the ponds, and also provided periodic maintenance to clean the pipes. Mz. Preston and Mr. Oslund were directed to go to the ponds and reverse the plates and stress to the golf course personnel not to touch them, and to give a copy of the report to the President of the Country Club and to the President of the Homeowners Association, with specific areas of concern highlighted. Ms. Sova recommended modification of the control structures, operation of the control structures to allow greater discharges i.n anticipat~,ot~ of major stoacm events.. SFWMD was requiring a permit for this,-which the Village could negotiate. Ms. Sova described recommended sizes for swales. Cost estimate for drainage system one was $175,500 which included everything except construction of wales, and included 25$ for contingencies. Cost estimate for drainage system two was $223,000 for option one, improving the existing drainage system, and $351,344 for option two, flow diversion. Option one was recommended for system two because of the lower cost. Ms. Sova recommended implementing the proposed improvements along with good maintenance and operation, to adopt a minimum of a 5-year 24-hour level of flood protection for the roadways, to select option one within drainage system two, and to set priorities to consider construction of the roadside swales as a top priority, which would facilitate permitting for all the other proposed improvements. Ms. Sova recommended that after construction of the swales, priority should be given to drainage system two over system one because the severity of flooding was greater in system two. Mr. Oslund explained that $140,000 had been budgeted over the next two years which could be applied to drainage system two improvements. Mr. Oslund explained that money Stoxmarater IItility Board Meeting Minutes April 30, 1998 Page 8 was available from FEMA on an individual project basis, and the Village would have to be very committed to the project, and provide supporting data to convince F?EMA it was a viable project, and funding would take approximately two years. Ms. Sova reported that SFWMD had had a program whereby a report such as the report she had prepared was submitted and if they deemed it one very sensitive to water quality issues they would set up a cost sharing program with the Village. Ms. Sova pointed out that not all the improvements had to be done at once, and this could also be used as a master plan. The pipes most needing attention at this time were those downstream of the control structures, along with improvement of the control structures. Councilmember Capretta suggested contacting the Tequesta Country Club and Homeowners Association to set up a meeting for this presentation to be given to them instead of mailing the report. Level of service recommended was 5-year .2~-hour for roadways Village-wide. Mr. ©slund stated he would discuss level of service with Ms. Sova. Mr. Ladd -commented the Comprehensive Plan would require an a~mmendment to change the level of service standards. Ms. Sova recommended in order to do the work incrementally that the roadside Swale program be continued, then apply for a conceptual permit with SFWNID so that all improvements would be approved, and when ready to do construction, start downstream construction first, then move upstream. SFW.NID would want to see construction of some swales when improvements were started. Cost of swales and their operation was discussed. Ms. Sova pointed out that the driveways could have pipes under them or be left alone. Education of the public regarding swales was discussed. Ms. Sova commented she could be available to give this presentation to the Tequesta Country Club Homeowners Association. Joe Full, 159 Country Club Drive, questioned what would be done about driveways when swales were installed, to which Village Manager Bradford responded that the interim policy meant that for driveway changeouts before the Village did a full-scale swale program people would be told to cut the u _ ~ ~ - _ H ,tom"- ii] ::, -i~yy.li`n-; - - -~ alt,^,' Wµ`d ~ '~.• T• .f3>F - N O o _S i ~ ___ m ~L , _ - L ~O ~ - N n N Y ~Ll\ o '~ ya d r 7 ~eiailEU>i:Ol _: t n ?o ~~l Aigil~l4:.~ ~ ~,:~ a ;; a _„ 'd Q- - 3 a~in~ ~ `, A~ 5 JQ oay ,~ ul >f~ouuad s -_ F, ul YJODUad N u. > - _ _--- .._, ~ Ul tc Pt~ol m Q' ~ in m y - V ~~~ ~ i',~l C ~ U ~ 1 rUf1i~, { LL 1 ~q Q~ p~. L ~ _. ~ m i<J ?. ~ ~ ~ ~l ~ ~J I ~ Y v r ° _ _ ° k~ - ~ ~ _ ~ F -a - _ .~a~,aaoJalnwu~ °~ ~' ~ '-~ g ~~ j a w _ n P ~-~ f i ~ and' ewiaU j ,- C-{_T~ .li~.r 1'~ ~ lQ alWl ~~±` pc! V-'rn3 7 .~ 7 fi' f _ ~ ~ n 5 ~ s' C~ ~ ~ _. :'lil' ~~ ~ `~a Y a- 1Q K'Ua(j ay41 ~ 4az ~" _ v"~ ~ ' NN _ ' ' ~s ~ to 1 .Q\ ~~NRr f)fr JQ `{JprlaU^fl _` -- •------ 1 va yaaJ~~ auoU•~ j ''~ , 3 ~,, ~y ~ c ~v W ~ - ;.r ~, N ,~ ~ ,~ ~ _ V ~ o ~ ~.. N ~ ~- ~ ~; ~ ~ a~ z ~I ~, C Q r, N '~ .~ `- Z r O qft _ 4 dg- -.Or It cad -W Ow - �+_' t*. _� ,v r � -jam L ' Wit• �. _ , � � ,.,,,, � � s.: fig* - —40 Proposed Improvement Svstem to Remain y rr •�.� � •� r'rr r ,., . ,�, ate.. y � ' �' _ �,+•'�fi�.; ''"' ' .t 'v R t f F i`- 'sue t�"F �+ �. a ♦ '•s ,;:Y-'+ -' ,� � ' y, •• '� tom. '`�` 49D 'Awl AiL dW dWVW SW Proposed Improvement wstem to Remain ~~-~~--~~~.7~er"h1 ~It ~ ~n"~r~;~i~~l'x~rilo'1 1 ~tJOr 11!J!llilt Itlb ~~c I~ 17.s/r I ~ ~ I i l COUNTRY ~" I ClU9 y` 1 ~- ~ FA! AY t • f~ ~ Lit , ~ _~ ~ ^ I w : .\. f I `~+ I ~ rs1 ~ Z,~ \ ~y Z tf' r~ :~ r~' POND ~ 5 ~` :vl f fir ~ 1s` ts~ ~ ~ ~ Z ~'' rrp tb~ ~\~` ZsY's~ ~ zs~ !~ 13~ tSl t5~ ~ Z t~7 rs5 ~a ~ Golfconrse \ N, zf~~ ¢ie `rs t5~ ~~ Zs~ Zir ~; t tr Z~ > ~' ~ :, r r; water control t~ ~ „18 t'~ •`• t -. ~42~~ ~ • ~~.~ ,~;_ structure ~ ,t ~s •' ~ _ P 0 N (~~ 6 LOXAHATCHEE RIVER ~~'~ "'~t ` POND ~ 2 , ~':\ ` :1-'~' 1 Exist 36'~ J;IOi ,. `~..w+~5^"~ • ~ ~' .~r~..J~" s '~ `~ ~, _ -1, ~~ ~~ ,. i ,9j ~Zs ~~ ` ;ad Golfconrse ~~ ;;r ~,~ ~ I "e` ,es - max, ~:,~ ~ ~ ~ ~~ ~-~ ~'b • ~ ~ 9/12 ~G~ "b ~i7; • ~ ~ 27~~ I.Ga, ro `~~~ p ;IG I,G~ ~ ~~ ~ ~ 9~ ;! ~ ~ ° ~ Si 1 ~ ,S --~ ist7 p r+~ J ~ ~~~ :~ ~ .` '~' DRAINAGE SYSTEM I Village of Tequesta Country Club Community Drainage Study Golf View Country Club Community Drainage System I Typical Conditions ~~ Pond No. 6 Fairway North Fairway North Fairway West System I Outfall 1 i 4 q N _ JJ .. ,o POND 16 ~~__~ = /~' ~ ~ , „ :s ,~ ra :r ~, n ~ t ~ ~' ' a ~ ~ ~ .aj STARBOARD WAY f ~ ss -^ .9• • ~ Deb ~~~{ ~,"~~:4--~~ `s' `6 POND BIM;NI ROaD .r~ ~• ~~ /'~,t` is ~ /rJ • ,~~... , os ~ .~ : = :, y' Golfcoarse ,099 `~~-'" ~ ' ~ '~ . ~a / 4~ r r4 ~ ~ ~~/ ~ ,~ 9G I ~ > ~(~ .~. !An%~M ~ ,~. "\ rd ~ ~> Mgr 92 t~zD ° / ,A ~ ., ~1 Q 1 ~ ~ /~ ~~ ~ e ~~~.,,•~~ ~ ~~~ ` e,~=;~ ~~ ~ si as U W ^! e ~ as~e ~ 8 ,a e. ~ Do ~ . -• _ ~" .,•~i~ ~ ~~ '1~., f!' ~2 "cam ~! \ \ ~ 1 .x~ ~ WINDWARD ~ ib (~! ~ , rz \ . • ro r~ AVE. ~ (I ~ f~ y,`D7~\ Gw \ i 1~ 72 ~ Water COntf01 ~ 'fl~ ~.'~~l ~ r~%~S structure ~ .~ .,~,, ~° `~ ~• ~ fllll(jij~l ^ Exist. 36° •~"°~~ ~ b~' •~ .ts s~ Go I s~ Go ~ - 4t / P~ .rGP Kl[, fk Da n .3/ SS SG SS ~ ~ f ~ Or ~ 27 5/ S? 3/ SZ OOX = rc ~ ~' LEGEND Drainage basin _ boundary Sub-basin boundary ••••••••••• Sub-basin designation Proposed pipe IIIIIIIIIIIIIIIIIIIIIIIIII replacement /9 43 ~~ ~4iV ' ~ j~ a ~ r ' S FR ~ ~~ 6 .~ ,~ h re DRAINAGE SYSTEM II Village of Tequesta Country Club Community Drainage Study 1 Country Club Community Drainage System II Typical Conditions Fairview East Fairview East Pond No. 1 Z Fairview West System II Outfall Riverside Drive ~' ~ ~'~"'••" ~ "` " ~ "~ ~ ~ 10•YEM CAPITAL IMPROVfi11AENT RAM FY 87 FY 98 FY89 FY00 FY Oh FY02 FY08 FY04 06 FY07 s to Drive Diwroion Pro' ~ ~ Fairview C. Drol Modification 6olhriew Drivs I e ModNleafion ~~~ C Club Drive Droinape ebn equeata Circle to 2 5 Club Drive 550,000 ,~ 0p0 8 e Road Drat a Im eM Rivsndds Drive Drofnays improvement 590,000 North Dover Rid F)roinage Improvement ~, Swab Resim 1 ~~ Video Droi S ~,~ 550,000 ,000 550,000 Cou Club Drainage Sbid 310,000 510,000 LOS Drains 1fi,000 Ra aeement 12, 550.000 550,000 ,000 Toro. ,ooc 1oz,ooo 1os,ooo oorooD ,ooo s~oQ ooooo goooo oogoo ooooo