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Resolution 179-1981L P.?' OLi?TION NO. 179-1981 WPFREA.S, the BOAPP OF COUNTY COMMISSIONERS OF MONROE COUNTY, FLORIDA, has received an application from Fla. Keys Aqueduct Authority, and WHEREAS, in compliance with State Statute, it is necessary as part of the permitting procedure to read the following Biological Assessment into the Record, as follows; The Applicant proposes to modify that portion of the Florida Keys Aaueduct Authority (FKAA) pipeline construction project concerning both construction methods and permit conditions to be utilized _ within the confines of Lake Surprise, Monroe County (D.F.R.. Permit No. 13 & 44-28299; see attached copies of original and proposed modified construction plans). Construction method modifications relate primarily to depositing excavated spoil materials on the lake bottom rather than on the originally -permitted adjacent U.S. Highway No. 1. roadway toe -or -slope. The latter spoil storage site was deemed infeasible by the project contractor (Latex Corporation) for several reasons (ie. insufficient surface area, impractical riprap substrated, excessive distance from excavation site and existing telephone/powerline/guard rail obstructions). The modi- fied deposition methodology proposed here (see attached plan sheet) involves temporarily depositing the pipeline trench spoil materials directly on the westerly adjacent Lake Surprise bottom for_mina a 13+ ft. wide by 5+ st. high mound across the entire, 3,000+ ft. long_ l.ak_e trench area (ie, 39,000 sq.ft./0.9+ acres; 2.000+ cu.-yd. of. materials). Upon completion of this phase of the project, the new Pipeline will be constructed, floated across the lake surface and sunk within the excavated trench (3+ week estimated time period). subsequently, the spoil materials will be used to backfill both around and over (6" minimum cover) the new pipeline. Additional (minor) construction method modifications include a reduction in the volume of dredge/spoil materials (3,000+ to 2,000+ cu. yds.) and resultant pipeline trench size(42-inch bottom width- -_1.0 ft.maximum depth) and the use of stringently employed turbi6ity control devices around the entire construction area to prevent excessive siltation of adjacent seaarass beds. The permit connition, modification proposed ?'ere relates to the particular time fc th_e year when said construction should take place. Due to e"he extremely productive and sensitive ecology of the Lake Surprise Area; it. ;-,as originally s.ti_^ulated that pipeline construction activities within the lal<:.e area. Ghould he restricted to relatively less 'bi_ol.ogically-nr.oducti.ETe times of the year (ie. , October to January or August). It is herein prcnosed that this permittable Lake Surprise construction period be extended to October to January of,"mid-June" to August. Fvidence supporting the "acceptability" of this modified time period is presented. in "Appendix D" of the application. The nroposed modifications per �i_ri o 'a. --onion of. the Florida. KeysAqueduct Authority water slir—,- mein pipeline construction porject (D.F.R. Perm t Na. 1 & 44-2!_'299)' + "To construct a water supol.y transmission main from. Florida City in Dade County to Stock Island in Monroe County. To excavate and refill to existing grade a trench covering a total surface area of 24 acres by dredgincr 99,226 cubic yards of material waterward and 52,101 cubic yards landward of MFW and subsequently depositing 88,437 cubic yards waterward and. 46;437 cubic yards landward of DIH'W. To temporarily place 3,100 cubic yards of material on 1.3 acres of submerged lands as work pads. To permanently place 410 cubic yards of material in submersed lands in association with five air relief valve vaults. LOCATION: Florida Bay, Lake Surprise and Sounds, bays, creeks and submerged lands adjacent to US 1 between Canal C-III and Key Largo., Boca Chica Key, Saddlebunch Key, Sugarloaf Key and Park Key in Dade and Monroe Counties: Sections 9,15,16,17,20,21,22,25,26,27,28, 33,36, Township 59 South, Range 39 Fast; Sections 31,36, Township 60 South, Range 40 East; Sections 13, 29, Township 67 South, Range 26 East; Section 34, Township 66 South, Range 27 Fast; Section 4, Township 67 South, Range 27 Fast; not in an aquatic preserve; Class II and. Class III waters." This porject is undertaken to relieve the frequently -overburdened existing water supply pipeline in an attempt to provide a dependable and safe water supply to Monroe County residents. An excellent description of the general history and biology of this area of the proposed pipeline is presented in the original biological appraisal of this project by Mssrs. Dumas and Kruer (April 2, 1980). "The original aqueduct, which this line will eventually replace, was constructed in 1942 by the U.S. Navy to supply fresh water to the Navy base in Key West. This line runs along and below ground in various places throughout the Keys. Where bridges are stationary, the pipeline is attached. On swing and draw bridges the pipeline is submerged well below marine substrate to protect against anchor damage. This present aqueduct is not only in a deteriorated state, but also too narrow to adequately supply the health and safety water needs of the Keys residents. Keys water demands are supplemented by a R.O. plant at Rock Harbor (Largo Key)and a Desal plant at Stock Island (which is constantly down for repairs). Storage tanks and pumps stations are located at strategic points along the Keys. Since early March 1980, the aqueduct authority has curtailed service between 12:00 a.m. and 5:00 p.m. to refill storage tanks, and reduce use of water by residents. Also, due to shortages, the authority has declared a moratorium on water hook-ups to aqueduct and has drastically reduced system pressures. The proposed trench site along U.S. #1, from the _fruit stand south of Florida City to M.M. 123, is generally dry, vegetated with Baccharis sp., Primrose willow, Autralian Pine, Dog Fennel, Brasilian Pepper, and where land is moist or wet, Typha sp. The old causeway borrow ditch varies in distance from the road between 30 and 80 ft. The vegetation in the wet ditch consists of Utricularia sp. Typha sp., Maidencane, and fresh water algae. Red mangroves appear at M.M. 119 as individuals, then increase in number and size south of C-111. Also present are Brazilian Pepper, Australian Pine, and black mangroves. This vegetation type continues to Largo Key. The substrate in the open water areas (Lake Surprise and contiguous salt water cells) is sediment, shell hash, organics, and small stones. Vegetation here consists of Thalassia testudinum, Halodule sp., red brown, and green algae." The entire 126+ mile project is being constructed within the Florida Department of Transportation U.S. Highway No. 1 roadway right-of- way. The Florida Keys Aqueduct Authority is also a state agency. It should also be noted that the entire northern stretch (ie, Florida City to Key Largo) of the project will be extensively mitigated as stipulated both in the above -cited permit conditions and more completely in Drs. A. Thorhaug and P. Schroeder's publication entitled "Mitigation Plan for Mangroves and Seagrasses - Florida Keys Water Authority"; March 1980; prepared for the applicant's agent, Greenleaf/Telesca Engineers. Although a substantial portion of this mitigation applies to emeraent wetlands vegetation (ie, mangroves), a significant amount of seagrass vegetation will also require mitigation efforts. Too lenahty to include here, I have taken the liberty of copying salient portions of the mitigation proposals presented in each of the above -cited documents (see attached sheets). Of importance here is the fact that due to the decrease in the pipeline trench dimensions and resultant volume of spoil material proposed here, the originally permitted mitigation plan for Lake Surprise seagrasses (ie, 20 ft. swath across 3.000 ft. length of lake; 60,00 sq. ft. ) will remain essentially unchanged even with the modified. spoil deposition methodologv. The modifications proposed here relate specifically to those pipeline construction activities undertake within the confines of Lake Surprise, in northern Key Largo, Monroe County. Lake Surprise consists of relatively shallow (less than 10 ft. deep), 600+ acre, natural, marine, lake waterbody. It is bordered to the south by Key Largo proper, to the north by Jewfish Creek waterway, to the northwest by Everglades National Park, to the northeast and east by the Crocodile Lake National Wildlife Refuge and Barnes Sound (Class III) waters and to the west by Blackwater Sound and Florida Bay (Class III) waters. Almost entirely surrounded by sensitive wetlands areas, the majority of the lake area is in pristine condition. The only significant developmental "disturbance" of the lake lies in its bisection (thru the approximate lake center) by U.S. Highway No. 1 causeway proceeding from the Florida Keys (Monroe County) to Florida City (Dade Countv). All available evidence concerning Lake Surprise suggests it to be an extremely productive waterbody contributing significantly to the local marine ecology. The proposed project area was inspected by the author on April 1, 1981 at a period of low water. It consists of a 46 ft. wide swath (ie, turbidity curtain enclosure area) of submerged lake lands situated between 12, and 58 ft. from the existing causeway riprap revetment (approx. lake center) and extending across the 3,000+ ft. lake lenath (ie, 138,000 sq. ft.; 3,1_7 acres). An excellent description of this submergent area and adjacent lands is provided by Dr. A. Thorhaug (ibid). "This is a dense Thalassia area and clearly a fisheries nursery. The Thalassia next to shore ranges from 700-2,500 blades/m2 although an average would be close to 2,00 blades/m2 (winter value). In some places near the northern end, there are patches but it has a thick covering in the middle. There is almost homogenous covering. The large folders of the riprap are home to snapper, many larval fishes in large schools and numbers, sinnecrab, lobster, and a lot of attached organisms. The area within the first 10-15 feet next to shore appear much more diverse in microanimal life than out further. This area plus the intertidal riprap appears a sensitive area. Going out up to 90-100 feet (viewed from zigzag transect) there appears to be no area better than any other for laying the pipeline. It is a very homogenous Thalassia bed with patches at either end." The "hemogenous Thalassia bed" over most of the lake bottom is interspersed with growths of Caulerpa and Dictyota spp. algaes "Attached organisms" associated with the causeway revetment inshore areas include mollusks, gastropods, sponges, anemones starfish, Nudibranchs, sea slugs and great variety and abundance of various algae species. Water quality throughout the entire lake area appeared excellent (clarity and circulation). Similarly, the best available description of Lake Surprise project area sediments is provided by the following excerpts from the Ardaman & associates, Inc. report presented in "Appendix C" by the applicant: "In general, the soil cover overlying bedrock in the three probes varied from 2.5 feet in P-3 to 6.5 feet in P-1. Two soil types were encountered in the probes: 1. A very soft, dark gray, highly organic wilt with traces of calcareous sand and occasions shell fragments, The soil had a very strong organic odor. A density test performed on a'relatively undisturbed soil sample provided a bulk density of 70.3 pcf., slightly denser than seawater. Mois- ture content determinations on the soil samples indicated moisture contents in the ranae of 1_82-460 percent (%). Due to the very soft nature of the soils, it was not possi- ble to determine strength characteristics, either in the laboratory or in the field. The soil due to its porous and organic mass is very compressible. The thickness of the layer varies from 1 foot in P-2 to 4 feet in P-1. 2. A light gray clayey calcareous sand. with shell fragments and of loose to soft consistency. The moisture content of one sample was 128%. This sand layer varied from. 1 to 2.5 feet in thickness in the three prober." Probing measurements performed during my inspection of the project area largely corroborated this date. Negative enviromental impacts from this portion of the pipeline construction project are expected to occur both "directly" (mechanical destruction of lake bottom) and "indirectly" (turbidity, siltaion, and spoil deposition). Foremost among the direct impacts will be the actual trenching/ excavation operation which is expected to totally remove 30,000 + sq. ft. (0.7 acres) of seagrass vegetation presently growing within the proposed construction swath across the lake. Since this impact was originally expected, permitted and included in the project mitigation plan (and has since been slightly reduced), it is herein suggested that this direct excavation impact, in this instance, be considered minimal. The proposed spoil deposition operation will also effect a 30,00+ sq. it. (0.7 acre) direct lake bottom impact. Whether or not this impact proves to be temporary or. "permanent" will depend both upon the length of temporary deposition time period and the specific technique used to remove said spoil materials from the deposition site to the pipeline backf_ill areas. The proposed deposition time period (3+ weeks), if strictly adhered to, should prove sufficiently restrictive to prevent excessive smothering of underlying seagrass vegetation. If not adhered to, however, significant additional impact could occur. The particular technique employed to remove the spoil material from the temporary deposition site could similarly result in a range of environmental impacts. If a "washing process" such as is suggested in "Appendix D" of -the application (p.2) is utilized, direct mechanical -type impacts would be minimal whereas indirect siltation impacts would be increased. If some type of mechanical scraping technique is employed for this purpose the reverse would occur. Indirect negative project impacts can be expected to occur during all phases fo the above -discussed. process. Such impacts will occur both from excessive turbidity levels created from said operations and .from the resultant siltation of adjacent lands. "Adjacent lands" in this context may be considered to primarily consists of those lands contained within the proposed. 46 ft. wide swath of turbidity curtains (ie, 78,000+ sq. ft. or 1.8+ acres; not including trench and temporary spoil deposition areas). Although it cannot be assumed that all such adjacent lands will be permanently impacted by the proposed construction operations, impacts in this area should be considered maximal due to the extremely fine nature of the Lake Surprise sediments. It should also be mentioned that, although modified, each of these projected impacts are addressed within the originally permitted mitigation plan. "Direct" project mitigation plans include Thalassia ssp. seagrass revegetation of a 20 ft. wide swath across the entire lake surface area (ie, trench and spoil deposition areas) in accor- dance with the methodology presented in the attached sheets. "In direct" mitigation plans require that "loss of seagrasses in areas outside the limits of construction ... shall be replanted at the same density... Mitigation requirements for these, and. all other areas shall be based on actual losses sustained durina construction (D.E.R. Permit No. 13 & 44-28299; Special Condition No. 5)" It therefore seems that the permitted mitigation plans do, in fact, cover the entirety of the expected project impacts. However, since past experience has proven in many instances that mitigation results are not always entirely successful, it is herein suggested that perhaps the best possible course of action is to minimize as much as possible the need for project mitigation. Under the provisions of Chapters 253 and 403 (F.S.) and Sections 17-3 and 17-4 (F.A.C.), I hereby recommend these modifications for Departmental approval. I offer the followina suggestions in the attempt to minimize the expected project impacts and resultant amount of required mitigation: 1. Specification that turbidity curtains be placed as close to- gether as is determined to be practically feasible. In this interest, it is suggested that said curtains may be sunk and anchored to the lake bottom to a depth just below the trenching barge draft. This procedure would afford a narrowing of the curtained area to 25 to 30 ft (ie, trench, spoil deposition and "working" room areal widths) which is presently restricted by the 40 ft. width of the trenching barge. The comparatively shallow water depth within the lake project area would seem to suggest that such a procedure is in fact feasible in this in- stance. 2. Specification that care be taken in removing trench spoil mater- ials from the temporary storage site to avoid excessive seagrass destruction. It is suggested that some type of flat -bladed shovel be used for this purpose (rather than a toothed blade) which would possible be provided with a softening cushion material (ie, foam rubber) to minimize the mechanical destruc- tion of existing seagrass vegetation. In addition, it is herein suggested that no more spoil materials be removed from this area than are absolutely necessary to adequately perform the required backfill of the pipeline trench area. It is suggested that natural currents in the area be permitted to complete the spoil ,removal process by a natural "washing of the area. 3. The author has no objection to the proposed modification of the "permittable" project time period in accordance with the dates suggested above provided the work can be completed promptly (ie. 3-4 weeks) and with a minimum of environmental disturbance, BE IT RESOLVED BY THE BOARD OF COUNTY COMMISSIONERS OF MONROE COUNTY, FLORIDA, that the above Biological Assessment has been read into the record and duly considered pursuant to Floirda Statute 253.124 by the Board of County Commissioners of Monroe County, Florida, thisl6th day of June , 19 81 at a regularly scheduled meetina. BOARD OF COUNTY COMMISSIONER OF MONROE .OUNTY, FLORID By Mayor„ (Seal) Attest: erk APPROVED AS 10 PORN AND FGAL Stff= MCY BY AftnWi Offm BOARU,OF COUNTY COMMISSIONERS Wilh4rgina Harvey, District 1 Curt Blair, District 2 Mayor Protem Jerry Hernandez, Jr., District 3 MAYOR George E. Dolezal, District 4 Ken Sorensen, District 5 "X OUNTY o MONROE KEY WEST, FLORIDA 33040 & (305) 294-4641 Monroe County Legal Department Key West, Florida 33040 �0 OFFICE OF: Planning & Zoning Dept. Public Service Center Key West, F1 33040 I, the undersigned, do hereby attest that all data and information is complete in the package of the applicant as follows: 1 Certificate of Complete Enclosures 2. Permi t / 3. Application for Permit ✓ 4. Site Plan v 5. Location Map 6. County Biologist Report e/ 7. DER Assessment 8. Resolution BY '�bg ouig:� Administrativ Secretary DATE Z .J d ZONING: GU MO N R O E '�, PLANNING, BUILDING & ZONING DEPARTMENT PER,1IT COUNTY - PERIMIT FOR EXCAVATION, THE DEPOSIT OF NO. !, FILL, OR STRUCTURAL ACTIVITIES IN THE F: WATERS OR WETLANDS OF MONROE COUNTY 1) Property owners name & mailing address 2) Date FOR DEPARTMENT USE ONLY Fla. Keys Aqueduct Authority kpr. 22, 1981 . P . , 0 . Box 1239 Resolution No. Key West, Fla. 33040 3) Phone number 296-2454 (Date: 4) Contractor or agent's name, mailing address & phone number 5) GREENLEAF/TF.LESCA 1100 Kennedy Drive, Room 12 Legal description of property: 17,20,21,28,33, 25,26,27, Section16,- 22, 15, Key_ 16,9,31,36 Township 59 S 60 S Lot 305 294-2352 Subdivision Block Range '19 F 40 E Street, road or mile marker LAKE. SUR.PR.ISF Volume of material: dredged/excavated filled deposited ZONING: GU PURPOSE: Cost of Permit 99,226c.y.52,101 c.y. waterward landward of M.H.W. of tl.H.W. 88,437 c.y. _46,437c.y. waterward landward of M.H.W. of M.H.W. Estimated cost of Construction Approved by Chairman BOARD OF COUNTY COMISSIONERS OF NIONROE COUNTY, FLORIDA Biologist Comments - Restrictions or Special Conditions if any: Conv in File Date Building Of-ficial NOW Greenlet-Telesca PLANNERS • ENGINEERS • ARCHITECTS 2650 SW 27th AVENUE MIAMI, FLORIDA 33133 PHONE: 305/444-8411 5 March 1981 Mr. Eric R. Loken Environmental Specialist Division of Permitting Florida Department of Environmental .11400 Overseas Highway Marathon, Florida Regulation 33050 Re; Florida treys Aqueduct Authority - modification of Construction Method at Lake Surprise - Job No. 1643.16 We are enclosing an application requesting a modification in DER Permit Iho. 13 & 44-28299 and U.S. Corps of Engineers Permit No. 8GM-0276 in the Lake Surprise area for the new Florida Keys aqueduct. The project, as permitted in this area, contemplated the placing of spoil material from the trench excavated in the lake bottom on the roadway embankment during the period of constructing the pipeline. This spoil material was to be replaced to re- fill the pipeline trench at the conclusion of construction and the disturbed area was to be replanted with seagrass in order to mitigate the damage resulting from this construction operation. This method of construction was contemplated through- out the 3,000-foot length of Lake Surprise. A detailed examination of this area by the contractpr indicates that there is not sufficient room beyond the guardrail to store the material excavated from the trench. Also, the loop clearance between the overhead telephone lines andthe existing highway guardrail make it impossible to use the equipment required to recover this material for refilling the trench once: the pipe has been laid. The modification requested by this application is the placing of the spoil from the trench under viater, adjacent to the trench during the period of pipe laying, rather than on the roadway embankment originally contemplated. Borings and addi- tional soundings taken throughout this area indicate that the trench width can be greatly reduced from that contemplated in the original permit so that the area of lake bottom to be disturbed by both the trench excavation and the spoil storage area will not exceed the 20 feet originally anticipated as a trench width. This modification also contemplates the installation of turbidity curtains en- closing a 46-foot wide area within which the entire pipe laying operation would be conducted. The considerably smaller quantity of excavation contemplated under this modification and the restricted working width between the sediment curtains would minimize the siltation on the lake bottom and would eliminate spillage of excavated material stored on the highway embankment into the ecologically active riprap area adjacent to the embankment, thus reducing the overall environmental impact under the modification now proposed over that for which the permit was originally granted. CLEARWATER • MIAMI • ORLANDO Mr. Eric R. Loken, Environmental Specialist Division of Permitting, DER 5 March 1981 - Page TEra While I believe that this application provides all of the information required for your consideration, I would very much appreciate your advising me promptly should additional data be required in order that it can be furnished without delay and the processing of this application can proceed promptly. Si ncerely, John W. Greenleaf, Jr., PE Chairman/Chief Executive Officer JWG:ipg cc: Farmers Home Administration, Att: Mr. Charlie B. Hudnell (w/encl) Messrs. Ron York and Henry Arroyo, SFWMD, (w/encl) Mr. Jack Goodridge, SFWP4D, West Palm Beach (w/encl) Monroe County Board of Commissioners (w/encl) Monroe County Building Department (w/encl) GREENLEAF-TELESCA • PLANNERS • ENGINEERS • ARCHITECTS PT A'3 dI"I(7, i3''ILT) C & 70'II'IC; 1)EPA"T lTNT PF.R"IT APPLICAT IO': MONROF- R FxrNITATIOl4, TYE DEPOSIT OF FILL, C ' UCT13RAL COUNTY ACTIVITIES 1:4 THE �-7ATF.RS OR WETLAND 01' `u,,4ROE COL"ITY 1) Pfoperty owners name & mailing address 2) Date one number 4) Key We r 7" A/. ..?.30 -00 Z � ��/•/I /�/ I �Q�� I �rGr 7✓r/ Co t actor or C7nt' name, nailing address, phone & certification number. -rec�/c4��Te�escq I l/O e e, Z Xev W x!f ,3.30 -%0 3os- 2Q¢'Z 3f Z 5) Le.n,a des,�r2o t /n oJp dz: Section,zg, f�b"9t3Key, Subdivision, Township, ,S $ �� s Lot, Block, Range, _ 3q JE Street, road or mile marker, (if. acreage) . oning, —(� 0 6) Describe the proposed activity, methods of constriction & amount of material (in cubic yards), to be excavated or discharged. Describe purpose & intended use of project. . oil EJICQV1414'1a,v 401 J'�i'enc* !hs'f4��4 ab o f 36 d%`�r i�r-Q�►s�irr�ori Mdr hop? 44d b4d �i ljsi;q ✓ dredged/excavated filled/deposited volume of. material:? ZZI. c. ��. !7 161 c. Y. 8dyC37 c. Y. 4 $7 c. V. w r��a dJ Ord �, o.� of TT H G? b _ :'T a J$ - 7) 'dame, address & zip code of water way. P�„OjGC7' I/'! Rlw A4. adjoinin-- property owners whose property affronts /441 J 4ceri71' �ra�e.-�y o w.�err ` tic�r�,e .r a-� .e w�'�� a) List other permits issued andjor applied for,vinclude applicant s name, for this site A, 11A b) If application has been submitted for this project (or one similar) in the past, explain reason for new application and give applicant's name if different from current applican t j. /V List all Federa and State ag neies that have received applications for this project , v. S,r�+y Ccar�o.r. • 4'.,y�'•see�-.r� F/oric/q D.E%QJ �o �' This completed application form will be accompanied by the following, or it will NOT Be processed. a) Two (2) sets of drawings, on 8� x 11 paper, showing location, plot plan, top view and cross section of proposal, drawn to scale. b) Application processing fee as follows:: y $25.00 for dredge, fill, docks OR any structures affronting natural water bodies. $10.00 for vertical seawalls on man=made bodies of water. $25.00 for any combination of the above activities per site. Application is hereby made for a permit to authorize the activities described herein. I certify that I am familiar with the information contained in this application, and to the best of my knowledge & belief such information is true, complete & accurate. I further certify that I possess the authority to undertake the proposed activities. All provisions of laws and ordinances governing this type of work will be complied with whether so_ecified herein or not. The granting of a permit does not presume to give authority to violate or cancel the provisions of any county, state or federal law regulating construction or performance of construction of his a of facility. C�=rc&.1/ �,i nnr„rn o a .e n v Date !For Department lase Only/ Pee & receipt 71 Approved by Ass.t. Director verson accepting application Cost of permit Estimate d cost o cons u P- 3 O w 5 ----- --- .— s O l' Sgti O w 2 SSS O 7— tsS = 10 e� DEPTM OF REFUSAL. 7-0 SAMPLER ADVANCE. ASSUMED BEDROCK. SOIL LEGEND O Msssl Dark gray organic silt with abundance of fine roots and some calcareous sand. Very loose and soft. Strong organic ordor. 4T Light gray calcareous sand. Very loose. Piston sample. Piston Sample. Full recovery Partial recovery. NOTES: I. The probes were performed between February 23, 1981. - -.,Probe sequencing: P-1 (9-10 a.m.) P-2 (10-11 a.m.), P-3 (11-12 a.m.) 2. Local tide tables should be consulted to obtain appropriate elevations. I I 39W'0j ArdamaniAssociates, Inc. Ganw,nieq ErWWOWa in Sod Woer,aniea, Foundations, and Ma»nd Twrteq I I SOILS INVESTIGATION LAKE SURPRISE f1; %.r jCWGMD M MATL: 2.-ZA-61 FILL NO. Arr/RGMFD Orr: 1-5305 moo' P-3 1 _ G5TATION 5453 450 eso' I STATION 5"5 *00 STATION PLl 5436 tso PROPo5E0 PIPELINE) F ALIGNMENT Lacd`(,C7N Hap — , , • r- , r- , .. - IN NOT TO SCALE 1 I-1IG14WAY Ardsman A Associates, Inc. C ultup EtWwws in Sod M4ctwncs, «.,i✓ rG Fooundotlons, and YdtofgI Tow" SOILS INVESTIGATIOFI LAKE SURPRISE mmo w.. GT,, C>,coaD or. DATE: 2 21-er a Ul it => � J V N� r LL OL {1. �-T tll VI Q W �••' VIU-i OL .. •�. ,r ,^ U1 W N Z Lj W f Q Q Xtnr U Li Ld O pX p r CL Z Q W W v -' a p J Z tf? Z }-- lo J Z > W O;� Q ��:24 W Q if) t L.1 LLI � Z d �O w �� O •1' rWZ a J�� Ld cz CL Q_I� wO ..J co U Ln N Z,- 0 w o Q Z C M, W� a YQ OW O W w Or LL �J ZOLJ O� QJv JL�- �r3 o 4� U� /r `;' .. . CrV J uo10 �w 1-' v N D oZU O U �X CO til )- W W QC) t \ (V Zor' QJ J u- a. =Rim D- i OJ •AF. � � �� a� Tyt�.� 1 •Y. Ap: M 3� �,,• ti y 71 �=•� _l w- '�Sti� yam• y- .► m 3Tr11 M%t -4'I.,I0"no�P 2"114 OrstrC Zrivlii� �NATER SUPPLY A TRA�1SMISSICk MAttJ FI.oR,IDA kE`f5 AQUEDUCT AuTKp�ITY GZ�MEWLaAF / TF-LSSCA t-ANNZ PRs-=NGIN2ugRS•ARCHITECT5 s141- Plat, ��v t O K . Z O 1i1 1 i�� Lilt 3 d d � a21:1 r LAKE su r"'ltS PERM17 MOOIFICATIOW RSV. 2 MAR 81 sNE=7 ►A3 of r LAKE su r"'ltS PERM17 MOOIFICATIOW RSV. 2 MAR 81 sNE=7 ►A3 of TOPS 17, FORM 3397 JITMO IN DEPARTMENTAL CORRESPONDENCE DATE Tune . 1951 SUBJECT Florida Kevs Aqueduct Autaority, Lalce Surprise Pineline. To T !,T k T)irPrtor DEP•T Planning. Buildin^ & Zoninr Environmental FROM Robert Dennis Biolnvist DEP•T Planning. Building & Zoning AW LF, GAL TWSP 59S, rGE 39E, SECT 17,20,21,28,33, 36, and TWSP 60S, RGE 40E, SECT 9,15,16, 22,25,26,27,31,36. Lake Surprise, Frey Largo. INTRODUCTION: On April 22, 1950, the Board of County Commissioners approved the excavation of Lake Surprise for the installation of the Aqueduct Authority pipeline. Approval was part of a larger application to trench wetland areas from canal C-111 to Key Largo (mile marker 116.75 to 106.7.5 along hi!hu-ay U.S.1). The dredge spoil from Lake Surprise was to be placed on the easement of U.S. 1 and used to covarthe pipeline after it wasin place. The applicants are now asking to modify this plan by placing the spoil on the lake bottom. Due to the unconsolidated nature of the lake sediment, placement of the spoil on the easement of U.S. 1 no longer appears to be a reasonable course of action. Therefore, the applicants would like to temporarily place the spoil on the lake bottom, adjacent to the trench for the pipeline. DISCUSSION: The trench site is 72-1 ft. from the center line of. U.S. 1 (T!est side) or approximately 34 ft. waterward of `!SL. A dense meadow of Thalassia (tur.tlegrass) covers this portion of the lake and perliaps the entire lake bottom as well. Turbidity screens will be placed appr.o::imately 50 ft. apart and trenc?iin� will be done along a line midway uetween them. The spoil will be Placed next to t;ie trench Ihut within the confines of the turbidity screens. After the pipeline is installed, the spoil will be used to cover the pipeline. Sea?rasses Will I)e replanted over the pipeline and in t'ie -idjacent imparted n.rea. Vie attac'ied. nepartmcat of environmental Regulation report discusses this prniect in considerable detail and should be consulted for additional inFor.ms.tion. TOPS FORM 3397 LITHO IN DEPARTMENTAL CORRESPONDENCE DATE Tune 3, 19Sl SUBJECT Florida Keys Aqueduct Authority, Lake Surprise Pipeline To T)afie t1,7o DEFT FROM DEFT EVALUATION: Tie major reasons for excavatinc, a trench and for locating it ai7a-v from t'10 includ^ ')ut are not limited to: 1. A(avoi(i.in,; the cnvironrient_illy sensitive habitat 1S_30riatI!,! �.'it:l Cie su'.T7,2rnlnd rip -ran alon!T TT.S. 1t 2. Advoidin{' e:-,cnssiuC s?2^rass destruction caused T)v th,1 movemte,its of 3 har.— `:!orkini-, in shallow water Providing prof: f �• ,_ ron van1s. atisrl and darlaRe c1usad ':y motor vehicles and boats, and 4. Pr.ovirlin some stalbility to the pipeline from hydrodynamic forces caused by water passing tilrough the completed Pipeline. RIZMal" E"MAT ION: Approval. e TW11j TOWERS OFFICE BUILDING 2600 BLAIR,STONE ROAD TALLAHASSEE, FLORIDA 32301 STATE OF FLORIDA 14 DEPARTMENT OF ENVIRONMENTAL REGU April 10, Florida Keys Aqueduct Authority c/o Greenleaf/Telesca 2650 Southwest'27th Avenue Miami, Florida 33133 Attention:' Mr. John Greenleaf, Jr.: Re: File No. 13&44-,415.13, Dade &. Mon Florida Keys Aqueduct Authority BOB GRAHAM GREENLEU JT�Q,- A• A DATE Nt'ii �. S jT81A ROUTING V. R4vg FE i �. AC ® �.,CIARAC NG3 � Sr�C~ CAD Ci_;'J RJF —K.W JFM QRC' LPP `ROR NU eFlun 4-51 As we advised you on April*9. 19R1 your application is incomplete without local approval, pursuant to Section 253.124, Florida Statutes, for filling waterward of the existing mean/ ordinary high water line. Please.submit the enclosed copy of our biological comments together with your permit application to.the.Bcard of.Courty- Commissioners/City Council or their authorized permitting authority. Section 253.124, Florida Statutes,.states that the .county conmaission/city council ". . .shall have in. hand the (biological) report.and findings thereof." It .further states, "The report shall be read into the record•and duly considered -at the same meeting at which the board of county commissioners or other authorized body takes -final action on the application for permit." You will need to obtain a copy of the minutes of the meeting or an appropriate indication of the local approval. This letter, resolution or copy of the minutes should be sent to this office. Your application will remain incomplete without valid local approval.- If you have any questions concerning this procedure, please contact us. Sincerely, Richard A. Lotspeich Environmental Specialist Standard Permitting Section Enclosure DER Form 17-1.122 (50) DEPARTMENT OF ENVIRONMENTAL REGULATION PERMIT APPLICATION APPRAISAL. File No.: 13 & 44-yi-s!3 County: Monroe Date: 4-7-81 Applicant Name: Florida Keys Aqueduct Authority Address; PO Box 1239, Key West, FL 33040 Agent (if applicable): Greenleaf/Telesca (Planners, Engineers, Architects, Address: 2650 S.W. 27 Avenue, Miami, FL 33133 1/,ZU,Zi Location of project: Section (s)28,33,36,Township 59S Range 39E 2 TI: Section(s)'Township 60S Range 40E 3 Local Reference: Lake Surprise Water Body: Lake Surprise Water Classification of Project Area: III Adjace J f�;ta",,'. Aquatic Preserve: Outstanding Florida Waters: None • V On site inspection by: Eric R. Loken frvI - /�'Ci'Y;;; �N Date of Inspection: 4-2-81 Original Application: Yes No X Revised Application: YesX No Date: Date of 2nd Insp. ' Biological and Water Quality Assessment A. Description of proposed project and construction techniques. Quantify area of project which extends into waters of the state (including the submerged lands of those waters and the transi- tional zone of the submerged land) as defined in Section 17-4.02 and Section 17-4.28, Florida Administrative Code. B. Biophysical features of general area. Include comments concerning extent of development of adjoining properties as well as relevant historical facts about the area. C. Biophysical features of specific project site and spoil site if applicable. Include identification of bottom types and any relevant historical facts about the area of the project. D. Potential impact of project on biological resources and water quality. Address long-term impact as well as immediate impact for all aspects of the project. E. Suggestions, where appropriate, for modifications that may reduce or minimize the potential impact of project. PERM 16-10(Rev.6/79) a FLORIDA KEYS AQUEDUCT AUTHORITY #13 & 44- 4'i,s/3 Monroe County - Lake Surprise Page Two A. The applicant proposes to modify that portion of the Florida Keys Aqueduct Authority (FKAA) pipeline construction project concerning both construction methods and permit conditions to be utilized within the confines of Lake Surprise, Monroe County (D.E.R. Permit No. 13 & 44-28299; see attached copies of original and proposed modified construction plans). Construction method modifications relate primarily to depositing excavated spoil materials on the lake bottom rather than on the originally -permitted adjacent U.S. Highway No. 1 roadway toe -of -slope. The latter spoil storage site was deemed infeasible by the project contractor (Latex Corporation) for several reasons (ie, insufficient surface area, impractical riprap substrate, excessive distance from excavation site and existing telephone/power line/guard rail obstructions). The modi- fied deposition methodology proposed here (see attached plan sheet) involves temporarily depositing the pipeline trench spoil materials directly on the westerly adjacent Lake Surprise bottom forming a 13+ ft. wide by 5+ ft. high mound across the entire, 3,000+ ft. long lake trench area (ie, 39,000 sq.ft./0.9+ acres; 2,000+ cu. yds. of materials). Upon completion of this phase of the project, the new pipeline will be constructed, floated across the lake surface and sunk within the excavated trench (3+ week estimated time period). Subsequently, the spoil materials will be used to backfill both around and over (6" minimum cover) -the new pipeline. Additional (minor) construction method modifications include a reduction in the volume of dredge/spoil materials (3,000+ to 2,000+ cu. yds.) and resultant pipeline trench size (42-inch bottom width; -3.0 ft. maximum depth) and the use of stringently employed turbidity control devices around the entire construction area to prevent excessive siltation of adjacent seagrass beds. - The permit condition modification proposed here relates to the particular time of the year when said construction should take place. Due to the extremely productive and sensitive ecology of the Lake Surprise Area, it was originally stipulated that pipeline construction activities within the lake area should be restricted to relatively less biologically -productive times of the year (ie., October to January or August). It is herin proposed that this "permittable Lake Surprise construction period" be extended to October to January or "mid-June"to August. Ev�rLc.e supporting the "acceptability" of this modified time per=d IS r*gs%ented in "Appendix D" of the application.Af) '' 1°A1 In 7v -d r- �:mmy Ln p op O I� rTt • --1 r r O L s i . j , ► i.. t: , �,.. t4.bif AsAwoonriro—, T fI8 F •+�:�' '!� ', ��. �ft�'•'�•1 ,��I t. �':�:�; �t it+�. �. �.r `r t��... .f •�:f.t J.. i•: ��•� �1.i �I:. r. �i �• � :i' ' +i �`� � '��J. •-�-.�.�.�. /_�. I FTLjhbiVITY CURTAIN =•_: 9XISTING 111P•RAP Its SToR 6 GV%ASSXS O`IRFI 8 _ •`i:� `' ENeANKMiNT OACKPILL � lN Ll. .� `••:1 ',� •I`IX• DoT`roM 6�SV. VAKIf� -�_ _ `�-�•..,. �' �q ANDY 66TTOM L1fCA ;i�:• TYPICAL PLAN SECTION AOCKlXCAVATIOW _ Tf%E NCN IN LAK� SUA M15E It � �G� t MIN• ANOY 6XD—' A1,T2 IAGKPILL 0 Tuhblvil,f CURTAIN --- - -MNW A M LW DIL AREA a:;, 8:. Ill 'l Tur oP ROCK -IJ I E VARISS it f uuNCIi WIDIA ry cc J ,�_. �-._ ti+ • f^+.+— .. ..f+'•'— . mil^ � •J�—... . .•,1.�. "�,.t ' � 1 .. . LAKE •SLJn'f'RlSE •�/ ai•YOriire::4s.vr{u.3w•�.ar•nT1�.�cv•:r:n.7n...._•:.•rA:�.•.L.::-:...r:r�.•M•:...-.:.-►L..rl::c�'.^.:•.�Lt•L�•r.: .: .JLvc...-L _:..c. •: '.a .._•zc ._.. ��.. .._ . TO 1 N -E0GE cis L.�,r►F O------------- r ` �` `f._i��+!'t r. _3�..^. � •.f .'.'f`r •"•i,'-• " •� <'„ — - --..'..i•,:.�.�:cris7•r T`s^'�•-•:,; t1ti•:�-'a—••.7�::.9�.:L� .r�.:.j� VP.RIES AS N_ECE55ARV TO MINIMIZE I FNvluorAMENTAL IMPACT -- -TUR6lb1TY CURTAIN . (5C7 VA SIDES OF T)ZENCH IN LAKE surzPti{ISE - ..PLASTIC COVER A, -LT, SPOIL A?Z1=A. L AKE s OTUEcz THAN LPAE SURPRI GRAS`- �� • (=L1rV, VAPIES PLASTIC COVER OVER 4 UNiDE1Z SP01L SI'o1L FROM LA1<C SURPRISE ! TRENH C, MXCESS SP01L TO E5E • . R -MOVED p>; i ER Tti`ENC N lS v�i I (3AGKFILLED �:; -// •R'ETAlt11NC1 BARRIER y�(ATE1Z SURFACEI M I-1V11 - REPLpI.IT OR RESTOR'c ' GRASSES IN WORK AKEA 5 HOUL•-�)ER RD-U�1 (!� UARD RAIL U PEC 6AGK OF PLAS` le- TO GROUND EXIST. 'ZIP -RAP EM5,P`9KMENT 1a"=MIN. 1— „PIPE `rvC- NCO-EXcAATE Td BOTTOM'OF FIPF PROVIDE NF-W 3!D PIPE 1' MIN. GOVER. V�pcKFILL WITI-1 GF011-• A,AQ REMOVE. �1y��1/j��i/ EXGE55 SPOIL NOTE , CONSTRUCTION IN LAKE. 50RPRI`S-E FROM OCT.-JAN. OR AUCi. TYPICAL PLAN AND SECTION -TRENCH N LAKE r FLORIDA KEYS AQUEDUCT GREENLEAP TELESCA PLANNERS • ENGWEERS ARCIiITECT NOT TO SCALE DATE: 2/15 /80 SHEET 2 OF 1 1 FLORIDA KEYS AQUEDUCT AUTHORITY # 13 & 44- yiusi 3 Monroe County - Lake Surprise Page Two A. The applicant proposes to modify that portion of the Florida Keys Aqueduct Authority (FKAA) pipeline construction project concerning both construction methods and permit conditions to be utilized within the confines of Lake Surprise, Monroe County (D.E.R. Permit No. 13 & 44-28299; see attached copies of original and proposed modified construction plans). Construction method modifications relate primarily to depositing excavated spoil materials on the lake bottom rather than on the originally -permitted adjacent U.S. Highway No. 1 roadway toe -of -slope. The latter spoil storage site was deemed infeasible by the project contractor (Latex Corporation) for several reasons (ie, insufficient surface area, impractical riprap substrate, excessive distance from excavation site and existing telephone/power line/guard rail obstructions). The modi- fied deposition methodology proposed here (see attached plan sheet) involves temporarily depositing the pipeline trench spoil materials directly on the westerly adjacent Lake Surprise bottom forming a 13+ ft. wide by 5+ ft. high mound across the entire, 3,000+ ft. long lake trench area (ie, 39,000 sq.f t./0.9+ acres; 2,000+ cu. yds. of materials). Upon completion of this phase of the project, the new pipeline will be constructed, floated across the lake surface and sunk within the excavated trench (3+ week estimated time period). Subsequently, the spoil materials w1*11 be used to backfill both around and over (V minimum cover) the new pipeline. Additional (minor) construction method modifications include a reduction in the volume of dredge/spoil materials (3,000+ to 2,000+ cu. yds.) and resultant pipeline trench size (42-inch bottom width; -3.0 ft. maximum depth) and the use of stringently employed turbidity control devices around the entire construction area to prevent excessive siltation of adjacent seagrass beds. The permit condition modification proposed here relates to the particular time of the year when said construction should take place. Due to the extremely productive and sensitive ecology of the Lake Surprise Area, it was originally stipulated that pipeline construction activities within the lake area should be restricted to relatively less biologically -productive times of the year (ie., October to January or August). It is herin proposed that this "permittable Lake Surprise construction period" be extended to October to January or mid -June to August. Evi-derice supporting the "acceptability" of 'this modified time eridd'i:s'• it „ „ P ;e�ented in Appendix D of the application. 1.981 �-- la r.. •�1 ••^�J-1! FLORIDA KEYS AQUEDUCT AUTHORITY # 13 & 44- y!V! 3 Monroe County - Lake Surprise Page Three B. The proposed modifications pertain to a portion of the Florida Keys Aqueduct Authority water supply transmission main pipeline conptruction project (D.E.R. Permit No. 13 & 44-28299): "To construct a water supply -transmission main from Florida City in Dade County to Stock Island in Monroe County. To excavate and refill to existing grade a trench covering a total surface area of 24 acres by dredging 99,226 cubic yards of material waterward and 52,101 cubic yards landward of MHW and subsequently depositing 83,437 cubic yards waterward and 46,437 cubic yards landward of MHW. To temporarily place 3,100 cubic yards of material on 1.3 acres of submerged lands as work pads. To permanently place 410 cubic yards of material in submerged lands in association with five air relief valve vaults. LOCATION: Florida Bay, Lake Surprise and Sounds, bays, creeks and submerged lands adjacent to US 1 between Canal C-111 and Key Largo., Boca Chica Key, Saddlebunch Key, Sugarloaf Key and Park Key, in Dade and Monroe Counties: Sections 9,15,16,17,20,21,22,25,26,27,28, 33,36, Township 59 South, Range 39 East; Sections 31,36, Township 60 South, Range 40 East; Sections 13,29, Township 67 South, Range 26 East; Section 34, Township 66 South, Range 27 East; Section 4, Township 67 South, Range 27 East; not in an aquatic preserve; Class II and Class III waters." This project is undertaken to relieve the frequently -overburdened existing water supply pipeline in an attempt to provide a dependable and safe water supply to -Monroe County residents. An excellent description of the general history and biology of this area of the proposed pipeline is presented in the original biological appraisal of this project by Mssrs. Dumas and Kruer (April 2, 1980): "The original aqueduct, which this line will eventually replace, was constructed in 1942 by the U.S. Navy to supply fresh water to the Navy base in Key West. This line runs along and below ground in various places throughout the Keys. Where bridges are stationary, the pipeline is attached. On swing and draw bridges the pipeline is submerged well below marine substrate to protect against anchor damage. This -present aqueduct is not only in a deteriorated state, but also too narrow to adequately supply the health and safety water needs of the Keys residents. Keys water demands are supplemented by a R.O. plant at Rock Harbor (Largo Key) and a Desal plant at Stock Island (which is constantly down for repairs). Storage tanks and pump stations are located at strategic points along..th7le., is ._ . FLORIDA KEYS AQUEDUCT AUTHORITY #13 & 44- -J//s/3 Monroe County - Lake Surprise Page Four Since early March 1980, the aqueduct authority has curtailed service between 12:00 a.m. and 5: p.m. to refill storage tanks, and reduce use of water by residents. Also, due to shortages, the authority has declared a moratorium on water hook-ups to aqueduct and has drastically reduced system pressures. The proposed trench site along U.S. #1, from the fruit stand south of Florida City to M.M. 123, is generally dry, vegetated with.Baccharis sp., Primrose willow, Australian Pine, Dog Fennel, Brasilian Pepper, and where land is moist or wet, Typha sp. The old causeway borrow ditch varies in distance from the road between 30 and 80 ft. The vegetation in the wet ditch consists of Utricularia sp. Typha sp., Maidencane, and fresh water algae. Red mangroves appear at M.M. 119 as individuals, then increase in number and size south of C-111. Also present are Brazilian Pepper, Australian Pine, and black mangroves. This vegetation type continues to Largo Key. The substrate in the open water areas (Lake Surprise and contiguous salt water cells) is sediment, shell hash, organics, and small stones. Vegetation here consists of Thalassia testudinum, Halodule sp., red, brown, and green algae." The entire 126+ mile project is being constructed within the Florida Department of Transportation U.S Highway No. 1 roadway right-of- way. The Florida Key Aqueduct Authority is also a state agency. It should also be noted that the entire northern stretch (ie, Florida City to Key Largo) of the project will be extensively mitigated as stipulated both in the above -cited permit conditions and more completely in Drs. A. Thorhaug and P. Schroeder's publication entitled "Mitigation Plan for Mangroves and Seagrasses - Florida Keys Water Authority"; March, 1980; prepared for the applicant's agent, Greenleaf/Telesca Engineers. Although a substantial portion of this mitigation applies to emergent wetlands vegetation (ie, mangroves), a significant amount of seagrass vegetation will also require mitigation efforts. Too lengthy to include here, I have taken the liberty of copying salient portions of the mitigation proposals presented in each of the above -cited documents (see attached sheets). Of importance here is the fact that due to the decrease in the pipeline trench dimensions and resultant volume of spoil material proposed here, the originally permitted mitigation plan for Lake Surprise seagrasses (ie, 20 ft. swath across 3,000 ft. length of lake; 60,000 sq. ft.) will remain essentially unchang^e,d.,_ ith the modified spoil deposition methodology. i;) `f FLORIDA KEYS AQUEDUCT AUTHORITY #13 & 44- -',�s/3 Monroe County - Lake Surprise Page Five C. The modifications proposed hE:re relate specifically to those pipeline construction activities undertaken within the confines of Lake Surprise, in northern Key Largo, Monroe County. Lake Surprise consists of a relatively shallow (less than 10 ft. deep), 600+ acre, natural, marine, lake waterbody. It is bordered to the south by Key Largo proper, to the north by Jewfish Creek waterway, to the northwest by Everglades National Park, to the northeast and east by the Crocodile Lake National Wildlife Refuge and Barnes Sound (Class III) waters and to the west by Blackwater Sound and Florida Bay (Class III) waters. Almost entirely surrounded by sensitive wetlands areas, the majority of the lake area is in pristine condition. The only significant developmental "disturbance" of the lake lies in its bisection (thru the approximate lake center) by U.S. Highway No. 1 causeway proceeding from the Florida Keys (Monroe County) to Florida City (Dade County). All available evidence concerning Lake Surprise suggests it to be an extremely productive waterbody contributing significantly to the local marine ecology. The proposed project area was inspected by the author on April 2, 1981 at a period of low water. It consists of a 46 ft. wide swath (ie, turbidity curtain enclosure area) of submerged lake lands situated between 12 and 58 ft. from the existing causeway riprap revetment (approx. lake center) and extending across the 3,000+ ft. lake length (ie, 138,000 sq. ft.; 3.17 acres). An excellent description of this submergent area and adjacent lands is provided by Dr. A. Thorhaug (ibid): "This is a dense Thalassia area and clearly a fisheries nursery. The Thalassia next to shore ranges from 700-2,500 blades/m2 although an average would be close to 2,000 blades/m2 (winter value). In some places near the northern end, there are patches but it has a thick covering in the middle. There is almost homogenous covering. The large folders of the riprap are home to snapper, many larval fishes in large schools and numbers, stonecrab, lobster, and a lot of attached organisms. The area within the first 10-15 feet next to shore appear much more diverse in macroanimal life than out further. This area plus the intertidal riprap appears a sensitive area. Going out up to 90-100 feet (viewed from zigzag transect) there appears to be no area better than any other for laying the pipeline. It is a very homogenous Thalassia bed with patches at either end." The "homogenous Thalassia bed" over most of the lake bottom is interspersed with growths of Caulerpa and Dictyota spp. algaes. "Attached organisms" associated with the causeway revetment inshore areas include mollusks, gastropods, sponges, anemones, starfish, FLORIDA KEYS AQUEDUCT AUTHORITY #13&44-411.5-13 Monroe County - Lake Surprise Page Six Nud,ibranchs, sea slugs and a great variety and abundance of various algae species. Water quality throughout the entire lake area appeared excellent (clarity and circulation). Similarly, the best available description of Lake Surprise project area sediments is provided by the following excerpts from the Ardaman & Associates, Inc. report presented in "Appendix C" by the applicant: "In general, the soil cover overlying bedrock in the three probes varied from 2.5 feet in P-3 to 6.5 feet in P-1. Two soil types were encountered in the probes: 1. A very.soft, dark gray, highly organic silt with traces of calcareous sand and occasions shell fragments. The soil had a very strong organic odor. A density test performed on a relatively undisturbed soil sample provided a bulk density of 70.3 pcf, slightly denser than seawater. Mois- ture content determinations on the soil samples indicated moisture contents in the range of 182-460 percent (%). Due to the very soft nature of the soils, it was not possi- ble to determine strength characteristics, either in the laboratory or in the field. The soil due to its porous and organic mass is very compressible. The thickness of the layer varies from 1 foot in P-2 to 4 feet in P-1. 2. A light gray clayey calcareous sand with shell fragments and of loose to soft consistency. The moisture content of one sample was 1287.. This sand layer varied from 1 to 2.5 feet in thickness in the three probes." Probing measurements performed during my inspection of the project area largely corroborated this data. D. Negative environmental impacts from this portion of the pipeline construction project are expected to occur both "directly" (mechanical destruction of lake bottom) and "indirectly" (turbidity, siltation, and spoil deposition). Foremost among the direct impacts will be the actual trenching/ excavation operation which is expected to totally remove 30,000+ sq..ft. (0.7 acres) of seagrass vegetation presently growing within . ilst _-�� Iwcass. GQI P-3 _ �STATIOb 5453 {"D 8SO' STATION 5".f+00 wo, 5TATION P-I 5436 "" 1�1- PROPOSED PIPELINE ALIGNMENT "AII •!T P- 11a10- • rl • (— 1 \ LL 1 1 ♦ i— LL NOT TO SCALE lw / HIGHWAY �M Ardsman&Associates, Inc. Cwwit" Env- in Soil Moel,�ies, ,rara.r Foundation*. and Matwool Tom" SOILS INVESTIGATION LAKE SURPRISE Sao or. Eo.rc z z „ate ....., ... M,.....:. St.) Scd -(%ko X C k'<3 P-1 R2 P- 3 O S O c5c ! �S 0 7- 6' 7- 2 S t rSS _ !O +� DEPTH OF REFUSAL . ~ S'• 2 TO SAMPLER ADVi4NGF. o /X A55UMED BEDROCK. 12'- p” SOIL LEGEND Oks` Dark gray organic silt with abundance �S of fine roots and some calcareous sand. Very loose and soft. Strong organic ordor. 0 4T Light gray calcareous sand. Very loose. Piston sample. Piston Sample. Fu11 recovery Partial recovery. NOTES: 1. The probes were performed between un February 23, 1981. .Probe sequencing: P-1 (9-10 a.m.) P-2 (10-11 a.m.), P-3 (11-12 a.m.) 2. Local tide tables should be consulted to obtain appropriate elevations. Ardantsn i Associates, Inc. Ca M"W4 &W"Ws in Sod MaefMwia, yw Foundations. and Maiend Toom SOILS INVESTIGATION LAKE SURPRISE „++a or G.-r jemimno a/r: o+T[: 2-a4•e1 'IL no. hORIDA KEYS AQUEDUCT AUTHORITY #13 & 44- yis�3 Monroe County - Lake Surprise Page Seven the proposed construction swath across the lake. Since this impact was originally expected, permitted and included in the project mitigation plan (and has since been slightly reduced), it is herein suggested that this direct excavation impact, in this instance, be considered minimal. The proposed spoil deposition operation will also effect a 30,000+ sq. ft. (0.7 acre) direct lake bottom impact. Whether or not this impact proves to be temporary or "permanent" will depend both upon the length of temporary deposition time period and the specific technique used to remove said spoil materials from the deposition site to the pipeline backfill areas. The proposed deposition time period (3+ weeks), if strictly adhered to, should prove sufficiently restrictive to prevent excessive smothering of underlying seagrass vegetation. If not adhered to, however, significant additional impact could occur. The particular technique employed to remove the spoil material from the temporary deposition site could similarly result in a range of environmental impacts. If a "washing process" such as is suggested in "Appendix D" of the application (p. 2) is utilized, direct mechanical -type impacts would be minimal whereas indirect siltation impacts would be increased. If some type of rnechanical scraping technique is employed for this purpose, the reverse would occur. Indirect negative project impacts can be expected to occur during all phases of the above -discussed process. Such impacts will occur both from excessive turbidity levels created from said operations and from the resultant siltation of adjacent lands. "Adjacent lands" in this context may be considered to primarily consist'of those - lands contained within the proposed 46 ft. wide swath of turbidity curtains (ie, 78,000+ sq. ft. or 1.8+ acres; not including trench and temporary spoil Reposition areasj. Although it cannot be assumed that all such adjacent lands will be permanently impacted by the proposed construction operations, impacts in this area should be considered maximal due to the extremely fine nature of the Lake Surprise sediments. It should also be mentioned that, although modified, each of these projected impacts are addressed within the originally permitted mitigation plan. "Direct" project mitigation plans include Thalassia spp. seagrass revegetation of a 20 ft. wide swath across the entire lake surface area (ie, trench and spoil deposition areas) in accor- dance with the methodology presented in the attached sheets. "In- direct" mitigation plans require that "loss of seagrasses in areas outside the limits of construction ... shall be replanted at the FLORIDA KEYS AQUEDUCT AUTHORITY # 13 & 44 - Monroe County - Lake Surprise Page Eight same density... Mitigation requirements for these, and all other areas shall be based on actual losses sustained during construction (D.E.R. Permit No. 13 & 44-28299; Special Condition No. 5)". It therefore seems that the permitted mitigation plans do, in fact, cover the entirety of the expected project impacts. However, since past experience has proven in many instances that mitigation results are not always entirely successful, it is herein suggested that perhaps the best possible course of action is to minimize as much as possible the need for project mitigation. FLORIDA KEYS AQUEDUCT AUTHORITY # 13 & 4 4 - 'S�isi3 Monroe County. - Lake Surprise Page Nine E. Under the provisions of Chapters 253 and 403(F.S.) and Sections 17-3 and 17-4 (F.A.C.), I hereby recommend these modifications for,Departmental approval. I offer the following suggestions in the attempt to minimize the expected project impacts and resultant amount of required mitigation: 1. Specification that turbidity curtains be placed as close to- gether as is determined to be practically feasible. In this interest, it is suggested that said curtains may be sunk and anchored to the lake bottom to a depth just below the trenching barge draft. This procedure would afford a narrowing of the CD curtained area to 25 to 30 ft. (ie, trench, spoil deposition and "working" room areal widths) which is presently restricted by the 40 ft. width of the trenching barge. The comparatively shallow water depth within the lake project area would seem to suggest that such a procedure is in fact feasible in this in- stance. 2. Specification that care be taken in removing trench spoil mater- ials from the temporary storage site to avoid excessive seagrass destruction. It is suggested that some type of flat -bladed shovel be used for this purpose (rather than a toothed blade) which could possibly be provided with a softening cushion material (ie. foam rubber) to minimize the mechanical destruc- tion of existing seagrass vegetation. In addition, it is herein suggested that no more spoil materials be removed from this area than are absolutely necessary to adequately perform the required backfill of the pipeline trench area. It is suggested that natural currents in the area be permitted to complete the spoil removal process by a natural "washing" of the area. 3. The author has no objection to the proposed modification of the "permittable" project time period in accordance with the dates suggested above provided the work can be completed promptly (ie. 3-4 weeks) and with a minimum of environmental disturbance. ( I.Zd ERIC R. LOKEN, EN7. SPEC. II Date: April 8, 1981 Read: GLEN BOE ERL/ dvo MITIGATION PLAN FOR MANGROVES 6 SEAGRASSES FLORIDA KEYS WATER AUTHORITY MITIGATION OF THALASSIA TESTUDINUM AMESI G/T 3/80 p1 An area 20 feet wide across Lake Surprise in the midst of a fairly dense Thalassia testudinum bed will be impacted. Since the biological study had to be carried out during a time of the year where no fruit would normally be available, it is impossible to say whether the Thalassia testudinum bed in Lake Surprise is a fruiting bed, so that seedlings would naturally recruit into the construction area. Therefore, it is recommended, partially due to the fact that Thalassia In normal occurrences only grows one to two feet laterally per year with its rhizomal system, and partially because the importance of the food web associated with Thalassia, that the 20 foot width be replanted with Thalassia nurseried seedlings (which is the best and most cost effective method of replanting Thalassia). The general features of the mitigation plan include Lake Surprise as an excellent low -energy, prolific seagrz:-s bed and a fine place to do a seagrass restoration. There will be no high wave action during the late summer and early fall when the restoration will occur, thus facilitating the project. Further, the bottom will be a sandy or u� A. d /�. ScYt rc� h� I % Oat, ,� nenter _ Qt, on �or Mal roue. i b � �eA rAS 2S �oric�G1 e C L// Qf a MITIGATION PLAN FOR MANGROVES S SEAGRASSES AMESI FLORIDA KEYS WATER AUTHORITY G/T 3/80 P7 muddy bottom of some several feet in depth so that the substrate will be ideal due to the shelter of the other seagrass around it. After the sc.';ment compacts, minimal erosion will probably occur; thus, the water quality and the sediment quality are thought to be highly auspicious for restoration. The recommended planting procedure is to plant Thalassia testudinum at one foot intervals starting three feet inside the parallel margins of the construction and going from one end of -ake Surprise to the other. No mitigation is recommended in the canal that runs northward from Lake Surprise which currently has marginal water quality. To plant seedlings, a guarantee requiring at least 70 percent of the seagrass mitigation. Plans are carried out successfully, and that the plants are healthy and expanding laterally within the first four years should occur. An investigator who has demonstrated prior success with Thalassia seedling restoration will be utilized. Physical observations of the seagrass regrowth at the various mitigation sites for the first year quarterly intervals, and afterward annual intervals should occur 'to determine the plant growth, their general health and document any colonization by macro -animals such as shrimp, fish, and lobsters in a monitoring program. • TABLE It. Mitigation Of vc,jcL.Itl.. COm,tunities, C-i11 L Lake Surprise w W O = R' w w W. Y F > W. u :L O o Ott ¢ m L Q W to I-- [t W OC Q m W Q NLm O J O >- O W Y O 2 K Q J O O J W Q 1•- Z = LD U U Y U W. ?C 7 U K u t7 O ¢ J r 1- W 1- "- — p F¢ 2 Q — ¢ C R x w ¢ J 4¢ OC O LINEAR METERS 1067 914 686 vi oo 1811 747 1►57 747 1798 6477 SQUARE 6504 5571 4182 ti610 11466 4554 2786 4554 10961 39484 METERS W r. W o x O Y Y W w W cc aC O W W O W N W N O Q Vf ? W W N W W W c9 h' N W w W W ►� Q cc W 17 W l7 W F O C7 S !� O i O ~ C Z W O O cc C w W O W ee J Q 1- w -J W Q== W Q O O= K O W O W = z Z a a. ct c6 x x x v u. L. z z n W C _ � W r\ M W N tA w all �p LAW W l7 V1 U .7 N ¢ �D F- ¢ 1-- ¢ Coa. 0.U. J O WN O C O lf, ¢ Cc? CL KNJ 0. a. CSJ a w n. prepared by A. Thorhaug F. P. Schroeder March 1980 AT-.PS/re njuslon-m- NW, OWING, / (o 1g9uLdLLc4 4L44AOril << PR osE cT N rTr_�ON ') 5) All areas vegetated by Thalassia testudinum or red and black mangroves (Rhizophora mangle and Avicennia g'erminans), where the vegetation is removed or destroyed by the process of construction, shall be replanted. The final extent of mitigation required shall be based on actual damage due to construction or construction -related activities. Final mitigation requirements shall be determined in consultation with the Marathon office of DER. Minimum mitigation requirements shall be as indicated in Tables 3 and 4 of the "Mitigation Plan for Mangroves and Seagrasses" prepared by Applied Marine Ecological Services, Inc., and as indicated below. Mitigation procedures and conditions shall be as indicated in that document, which is by reference incorporated into the permit conditions. Planting procedures for mitigation shall be as follows: Thalassia testudinum - Seedlings or transplants shall be planted at one ft. intervals beginning three ft. within the limits of construction in Lake Surprise. Loss of seagrasses in areas outside the limits of construction due to sedimentation, spillage or the inadvertant deposition of spoil, or erosion of spoil from the temporary spoil sites shall be replanted at. same density. ,. Patch red mangrove g rove - propagules shall be planted at square �teEei" intervals. �a'+ `A W 9 JOS , Thick red and large mature red and black mangroves - propagules shall be pl anted at square meter i nterval s and nurseti ed or tranW.aghtM14V: plants shall be planted at four square meter intervals. pERtt;lTl{NG Patchy black mangroves - propagules shall be planted at four square meter intervals. In addition to those areas indicated in Table 3 of the "Mitigation Plan for !-'angroves and Seagrasses", the following areas shall also be replanted: Temporary Spoil areas - All spoil shall be removed at the termination of construction and the area returned to natural grade. Mangroves shall be replanted according to the schedule indicated above and the area shall be mulched. Mitigation requiredrr,!nts for these, and all other areas shall be based on actual losses sustained during construction. Final mitigation requirements will be determined in consultation with the DER Marathon office within 30 days of the completion of each segment. The permittee, its agents and contractors, shall provide the contractor, or subcontractor, responsible for mitigation with the opportunity to remove existing vegetation from the proposed construction corridor for subsequent transplanting and shall provide suitable space for the maintenance of this.. vegetation during construction. •,�.«. The Authority's contracts for the completion of work requiring ml t1 gation shall provide that the Authority shall withhold total payments -Of .1QT of the mitigation contract until revegetated sites have shown an eighty.-(8O) percent survival rate for one year after replanting was completed.- Those areas demonstrating a lower survival rate shall be replanted.to a density equivalent to 80°� survival of the original planting. r 0 ' JOINT APPLICATION DEPARTMENT OF THE ARMYiFLOR)DA DEPARTMENT OF ENVIRONMENTAL REGULATION FOR ACTIVITIES IN WATERS OF THE STATE OF FLORIDA Refer to Instruction Pamphlet for explanation of numbered items and attachments required. 1. Application number (To be assigned) 2. Date 3. For official use only Day Mo. Yr. 4. Name, address and zip code of applicant FLORIDA KEYS AQUEDUCT AUTHORITY P. 0. Box 1239 Key West, Florida 33040 Telephone Number (305) 296-2454 5. Name, address, zip code and title of applicant's authorized agent for permit application coordination GREENLEAF/TELESCA.PLANNERS.ENGINEERS.ARCHITECTS, INC. 2650 S.W. 27 Avenue Miami, Florida 33133 Telephone Number . (305) 444-8411 6. Describe the proposed activity, its purpose and intended use, including a description of the type of structures, if any, to be erected on fills, or pipe or float -supported platforms, and the type, composition and quantity of materials to be discharged or dumped and means of conveyance. Modification to Permit No. C.O.E. 80M-0276 and D.E.R. No. 13 & 44-28299 See Appendix "A" Dredged/Excavated Filled; Deposited Volume of Material: 1,917 CY CY 1, 17 CY CY Lake Surprise Waterward of landward of Waterward of landward of p O.H.W. or M.H.W. O.H.W. or M.H.W. O.H.W. or M.H.W. O.H.W. or &I.H.W. 7. Proposed use i Private [ 1 Public (]d Commercial ( ) Other [ j (Explain in remarks) 8. Name and address including zip code of adjoining property owners whose property also adjoins the waterway. See Appendix "E"and U.S. Dept. of Interior (Everglades National Park) Item 9 below: T59S- R39E- Sec. 17, 20, 21, 28, 33, 36, 25, 26, 27, 22, 15, 16, and 9. I T60S-R40E- Sec. 31 and 36 9. Location where proposed activity exists or will occur Street addresl Lon 'tude80 22' to 80027' Latitude�5010' to 25017' 9(If known) Sec. See Above Twp 60S and 59S ege, 40E and 3qF Florida Dade and Monroe _ Stata County In Cay or Town Near City or Town 10. Name of waterway at location of the activity Flori da Keys: Lake Surprise SAJ FOR14 983 21 Jul 77 11. I' ate activity is pronosed to commence 1 June 1981 Date activity is expected to be completed August 1981 12. Is any portion of the activity for which authorization is sought now complete? Yes [ j No )fxl If answer is "Yes" give reasons in the remarks section. Month and year the activity was completed . Indicate the existing work on the drawings. 13. List all approvals or certifications required by other Federal interstate, state or local agencies for any structures, con- struction, discharges, deposits or other activities described in this application, including whether the project is a De- velopment of Regional impact. Issuing Agency Type of Approval Identification No. Date of Application Date of Approval S.F.W.M.D. Permit 7163 Feb, 14, 1980 Mar. 13, 1980 Florida DOT Permit 081-80 s 078-80 Project is not considered a DRI 14. Has any agency denied approval for the activity described herein or for any activity directly related to the activity de- scribed herein? Yes (] No iol (If "Yes" explain in remarks) 15. Remarks (see Instruction Pamphlet for additional information required for certain activities) See Appendix "D" 16. Application is hereby made for a permit or permits to authorize the activities described herein. I agree to provide any additional information/data that may be necessary to provide reasonable assurance or evidence to show that the pro- posed project will comply with the applicable State `hater Quality Standards or other environmental protectton stan- dards both during construction and after the project is completed. I also agree to provide entry to the project site for inspectors from the environmental protection agencies for the purpose of making preliminary analyses of the site and monitoring permitted works, if permit is granted. I certify that I am familiar with the information contained in this application, and that to the best of my knowledge and belief such information is true, complete, and accurate. I fur- ther certify that I 'possess the authority to undertake the proposed activities. Signature of Applicant Date 18 U.S.C. Section 1001 provides that: Whoever, in any manner within the jurisdiction of any department or agency of the United States knowingly and willfully falsifies, conceals, or covers up by any trick, scheme, or device a material fact cr makes any false, fictitious or fraudulent statements or representations or makes or uses any false writing or document knrvling same to contain any false, fictitious or fraudulent statement or entry, shall be fined not more than S10.000 or imprisoned not more than five years, or both. The application must be signed by the person who desires to undertake the proposed activity, however, the applica- tion may be signed by a duly authorized agent if accompanied by 3 statement by that person designating the agent and agreeing to furnish upon request, supplemental information in support of the application. FEE: Attach Checks/Money Orders on front Payable to Department of Environmental Regulation $200 Standard form projects S20 Short forms and Chapter 403 projects only INFORMATION NEEDED ON AFFIDAVIT OF OWNERSHIP OR CONTROL 1. The- affidavit of ownership or control should be signed by at least one owner of the property, les- see, or easement holder. 2. If subdivided, the property should be described by' lot number, block number (if any), name of subdivision, and plat book number and page where recorded. 3. If unplatted, the property should be described by section, township; and range, and subdivision of section. 4. If the description is based on courses and distances not following the plane coordinates, the point of beginning should be identified. Please contact this office should clarification or further insmctions be necessary. AFFIDAVIT OF OWNERSHIP OR CONTROL TO THE DEPARTMENT OF ENVIRONX ENTAL REGULATION: I hereby certify that I am the (check one) : record owner lessee NOT APPLICABLE record ease- ment holder applicant to record owner for easement of the below described property situated in County, Florida; and that said property is all 'the property that is contiguous to and landward of the area in which the work proposed in the permit application is to be conducted. Furthermore, I certify that as record owner, lessee, or record easement holder I have or wi.il have prior to undertaking the work all necessary approvals or permission from all other persons with a legal interest in said property to conduct the work proposed in the permit application. LEGAL DESCRIPTION NOTE: The Florida Keys Aqueduct Authority (FKAA) is a state agency, and will construct the project entirely within the right-of-way of another state agency, Florida Department of Transportation, from which a permit has- been obtained. The existing aqueduct is also located within the DOT right- of-way. The -right-of-way is a matter of public record. Sworn to and subscribed before me at County, , this day of 19 NOTARY PUBLIC My commission expires: u, (A Z d p d C 7 � ' Y cc 0 1 awflcc LLI V 2 a _1 LU N } W W = W YY Ix o J� ~dam CC LL.LLj N a t Q O 6, LV ww> w _! Z u I-JL Z Z (1) - U. W tiA► 52 ir� W wz c a Lu O;R ji o v Zv E- / ® -4 X o N J ' Y} f } Y J ?I 0 Y 4 =Z t J C d 3:3; v LLI W Z 1/ W 4 S W Y a u <! C t � V N O Y r = UO i �a O �w LL w �Y C? U W r U V mu U Z U.)Ld to } N Ld I F-I _.� 31rI1 MT-{ saurd' NO,uo4y Y v 0 z •trIw i tic L,4 o- cc a s .- r al o d u u N ?' N ~ Id � onno>�n �1+cMd3't�3.J VA r CV'SKG sNap I I`IY did iwna ja JIV-Efy- 'HATER SUPPLY 4 TRANSMISSIOR MAIM FLORIDA kEiS AQUEDUCT AuTHOgITY GZEEN LEAP / TELSSCA PLANN eRS • ENG+NEP-AS • ARGK ITEGTS T� LAKE SURPRISE PERMIT MODIFICATtaki REV . 2 MAR 81 SKEET M3 of APPENDIX "A" FLORIDA KEYS AQUEDUCT AUTHORITY C.O.E. Permit No. 80M-0276 F.D.E.R Permit No. 13 & 44-28299 LAKE SURPRISE PERMIT MODIFICATIONS Due to conditions encountered in the field, it is necessary to modify the present Corps of Engineers and Florida Department of Environmental Regula- tion permits outlined as follows: • Sheet 2 of 7 (Existing permit drawing number) shall not apply to the Lake Surprise area. In lieu thereof, the following sheets have been added as supplemental information for the trenching, turbidity control, spoil and backfill operations for Lake Surprise: Sheet No. M1 of 3: Project Location Map Sheet No. M2 of 3: Lake Surprise Location Map Sheet No. M3 of 3: Typical Plan and Section - Trench in Lake • In lieu of depositing the spoil on the bank, deposit spoil outboard of the shore line in a confined area as shown on Sheet M3 of 3. Turbidity curtains will be placed on each side of the trench which will protect the grass area along the rip -rap embankment as well as the grass area waterward. The 2 curtains will be placed about 46 feet apart which is the minimum distance required for the trenching from a barge. Trenching depth will be kept to.a minimum to reduce the quantity of spoil to be handled. The elevation of the pipe has been raised to reduce the excavation material, yet, maintaining a minimum clear water depth of 4 feet below MSL. Soundings taken at 100 foot intervals indicate various rock elevations below the lake bottom as indicated in Appendix "B". In addition, borings were taken to determine soil conditions; see Appendix "C". From this information we had determined that the cross section indi- cated on Sheet M3 of 3 is a workable solution that minimizes any environmental impacts. • The total excavated/dredged material below MHW is estimated at 1,917 cubic yards. This material will be placed along side the trench; and after the pipe has been layed, the spoil material will be used to fill the remainder of the trench and cover the pipe. Appendix "A" - Continued With the small amount of excavated material it has been estimated that any siltation resulting from the trenching operation in undisturbed grass areas will be less than 1/2-inch. This is well within the tol- erance levels of the grasses to sustain growth; This siltation will be washed toward the trench during back filling operations (See Appendix "D"). Replanting and grass restoration will be accomplished in the dis- turbed area over and on each side of the pipe area as a mitigation procedure. • Dredging in the lake area will have turbidity curtains or other approved devices installed during the construction period to contain the area and prevent turbidity in adjacent waters. These curtains will be removed after the work has been completed and any turbidity has diminished. APPENDIX "B" LAKE SURPRISE SOUNDINGS STATION ROCK ELEVATION LAKE BOTTOM ELEVATION 0 -9.0 -6.5 1 -8.3 -6.5 2 -7.7 -5.3 3 -8.3 -4.0 4 -7.5 -4.2 5 -8.3 -4.5 6 -6.8 -4.5 7 -6.5 -4.7 8 -6.3 -5.0 9 -6.6 -5.5 10 -8.2 -6.5 11 -6.8 -5.5 12 -6.5 -5.0 13 -6.5 -4.5 14 -6.5 -4.8 15 -6.3 -4.3 16 -6.3 -4.7 17 -6.7 -5.0 18 -6.2 -4.6 19 -6.2 -4.5 20 -6.2 -4.6 21 -5.8 -4.3 22 -5.7 -4.6 23 -5.6 -4.0 24 -5.4 -4.6 25 -5.3 -4.3 26 -6.3 -4.3 27 -6.0 -4.0 28 -5.0 -4.3 29 -7.6 -4.3 30 -6.5 -4.0 31 -6.0 -4.0 32 -6.7 -4.0 33 -7.0 -2.0 .j Ardaman & Associates, Inc. Consulting Engineers in Soil Mechanics, Foundations, and Materials Testing Greenleaf/Telesca 2650 S.W. 27th Avenue Coral Gables, Florida �ptFPCi�1D1Xof •G :Fehxaary 25, 1981 File No., 81-5305 Att: Mr. John Greenleaf SUBJECT: Report on Soils Investigation { Proposed Florida Aqueduct Pipeline, Lake"Surprise Key Largo, Florida — - Gentlemen: In accordance with your request, Ardaman & Associates has completed a soils investi- gation along the proposed Florida Aqueduct pipeline alignment in Lake Surprise at Key Largo, Florida. The purpose of the investigation was to define and assess the engineering properties of the lake bottom soils, and to assess the stability of these soils during trenching operations for the proposed pipeline. The following report presents our findings and recommendations. The report has been prepared for specific application to the above project, in accor4ance with generally accepted soils engineering practices. No other warranty, expressed or implied is made. FIELD INVESTIGATION Three soil probes were performed from a boat on February 23, 1981 at the locations shown on Figure No. 1. The soils overlying bedrock were sampled by the use of a piston sampler and the soils samples retained for laboratory testing. The soil probes and sample locations are presented on Figure No. 2. An attempt was made to measure the shear strength of the soils by an in -situ vane shear test. The resisting moment to turning as measured by the torque wrench was not measurable, indicating near zero shear strength. The probe locations were set out by representatives of Latex Construction Co. SOIL PROFILE AND PROPERTIES The soil profile as encountered in the trench probes is shown on Figure No. 2. The boring logs were prepared from the field logs after examination by a soils Post Office Box 3557, Cocoa, Florida 32922, Telephone (305) 632-2503 Offices in: Bartow i Cocoa ; Fort Myers / Orlando / Sarasota / Tallahassee y_1 • February 25, 1981 File No. 81-5305 Page - 2 - engineer, supplemented by the results of a laboratory testing program. The strat- ification lines represent the approximate boundary between soil types. In general, the soil cover overlying bedrock in the three probes varied from 2.5 feet in P-3 to 6.5 feet in P-1. Two soil types were encountered in the probes: 1. A very soft, dark gray, highly organic silt with traces .of calcareous sand and occasional shell fragments. The soil had a very strong organic ordor. A density test performed on a relatively undisturbed soil sample provided a bulk density of 70.3 pcf, slightly denser than seawater. Mois- ture content determinations on the soil samples indicated moisture contents in the range of 182-460 percent (%). Due to the very soft nature of the soils, it was not possi- ble to determine strength characteristics, either in the laboratory or in the field. The soil due to its porous and organic mass is very compressible. The thickness of the layer varies from 1 foot in P-2 to 4 feet in P-1. 2. A light gray clayey calcareous sand with shell fragments and of loose to soft consistency. The moisture content of one sample was 128%. This sand layer varied from 1 to 2.5 feet in thickness in the three probes. A summary of all test results are,provided in the attached Table I. CONCLUSIONS AND RECOMMENDATIONS The organic soils encountered in the lake are of extremely low strength. It was impossible to determine shear strength either in the laboratory or by in -situ tests. The low saturated density and high moisture contents indicate a highly compressible and low strength material. Any load applied to the surface of this soil will initiate excessive vertical soil deformations and horizontal displace- ments. With respect to the proposed trenching operation in Lake Surprise, we recommend that the contractor be allowed to proceed by trial and error in his trench ex- cavations in order to establish a trench configuration that will remain stable during pipe installations. _-3, Ardaman &Msociabes, Inc. A February 25, 1981 File No. 81-5305 Page - 3 - It is recognized that no space is available between the U.S. #1 Highway and the shoreline for temporary storage of the excavated trench soils. This was the area designated and approved by the DER for this project. , The excavated trench soils may, however, be temporarily stored on the lake bottom with the DER's approval. In this context it is stressed that the excavated mate- rials should not be concentrated near the trench, as this load on the soil may induce horizontal soil displacements and potentially push the soils back in the excavated trench. It is recommended that the excavated soils be temporarily stored on the lakeside of the shoreline so as not to impact trench stability. It has been a pleasure to be of assistance to you on this project. If you have any questions in regard to the contents of this report, please feel free to call US. Yours very truly ARDAMAN & ASSOCIATES, Inc. Carl H.D. Henriksen, P.E. Florida Registration No. 24133 CH:db -Ardaman8�Associabes,lnc. A lf •'� K&C 19 1153 2-79 MC39640 W :iC Q v 17//IrT r- i A.It' NOT TO SCALE P_ 3 I 11 1I ®STATION 5453 4sv 8so• I STATION P-2 5445+00 mot STATION P-I 543Go t3O U. S. HIGHWAY PROPOSED P/PE1/NE ALIGNMENT r tln1 Gl\ 1 VL $AIM Ardaman&Associates, Inc. Consulting Engkwws In Soil Mechonic's, rekrMAZ Foundations, and Materal Testna SOILS INVESTIGATION LAKE SURPRISE �z) P- I P-2 P- 3 p W 5 s O sys O LIOD 7=6' 7-Z'10DEPTH of REFUSAL 7-0 SAMPLER ADVANGF. c ASSUMED BEDROCK. SOIL LEGEND ( nss,� Dark gray organic silt with abundance of fine roots and some calcareous sand. Very loose and soft. Strong organic ordor. O? Light gray calcareous sand. Very loose. Piston sample. Piston Sample. Full recovery Partial recovery. NOTES: I. _i.,___ .nn n,nn The probes were pertrormeu beiY'rCeil nuu-+Li-.Uu U Ill. uil February 23, 1981. Probe sequencing: P-1 (9-10 a.m.) P-2 (10-11 a.m.), P-3 (11-12 a.m.) 2. Local tide tables should be consulted to obtain appropriate elevations. Pr7 Ardsman & Associates, Inc. Consulting Engeows in Soil Mucom ics, Foundations, and Motwvol Tog" SOILS INVESTIGATION LAKE SURPRISE r G.-r e"', roTay. DATE:2-Z•-ai D. •rn7 n�-i � j ,. 305 G.r.�l � Figure No. 2 File No. 81-5305 u TABLE I LABORATORY TEST RESULTS Probe No. Sample No. Depth of Sample Moisture Bulk Dry Below water line Content (%) Density Density (Feet) (pcf) (pcf) P-1 1 5.5-7.0 460 70.3 12.6 P-1 1 7.0 396 P-1 2 9-9.5 429 P-1 3 10-10.5 314 P-2 1 5-6.5 222 P-3 1 4.75-5 182 P-3 1 6 128 APpeNDnX-" FLORIDA KEYS WATER PIPELINE Appendix to Ecological Report A. Thorhaug, Ph.D. There are several major points about the -modification to the Lake Surprise dredging in the Florida Keys Pipeline project which have not been addressed in previous reports and warrant present discussion. 1. Effect of silt on seagrasses There are two major occurrances which are likely to take place in Lake Surprise due to the new plan to spoil overboard on thirteen feet of seagrasses next to the trench. a. An area 3000 feet long by 13 feet wide is going to be covered by silt for approximately three weeks while the trench is being dug and the pipe laid. There is the possibility that the covered blades will die, but that new blades will regrow. This is based on our data from the Card Sound canal of Florida Power and Light Company where a Thalassia station which had been observed bimonthly for two years prior to the construction of the canal was smothered under construction materials in two to three hectares. A leaf -kill occurred and blade counts dropped from 497 m-2 to 0 m-2. The rhizome system was not destroyed by siltation. When the silt was removed by opening the canal and allowing the current to carry the silt away, the regrowth of blades recurred in several months. We noted a similar occurrance in our five year study of Anclote Anchorage (28 miles north of Tampa Bay). A major leak in a dredging project by the U.S. Army Corps in the estuary covered a large seagrass bed in August. Fall storms reexposed the beds and the leaves regrew.*. b. A certain amount of siltation can be sustained by Thalassia. Many areas on the Florida Bay side of the Keys have Thalassic blades where the bottom portion has fine silt covering it. At the Virginia Key Beach fill project in 1973, where the seagrass beds were accidently exposed to repeated high siltation while the berm behind which fill was to be put broke repeatedly, the Thalassia were able to sustain this silt load of several inches. -2- The calculation of the worst possible case due to the silt, (all the silt is completely dispersed within the 60 foot curtain) the silt would be 0.5 inches deep. The Thalassia in this area should be able to sustain this amount of siltation for several weeks with a return to normal condition within two to three months after the curtains are removed. Evidently a washing technique would be institu- ted in this case which would not damage the seagrass while putting the silt back into the trench. No scraping would be used. 2. Protection of riprap environment The area where the pipeline curtains will be placed are to be twelve feet offshore from the toe of the riprap. The biological survey found the submerged portion of the riprap full of organisms and schools of minnows and other larger fishes using the immediate area for shelter from the riprap to 10 to 15 feet from the riprap. Thus, it was recommended that the construction of the pipeline be put further offshore to minimize the impact. The contractor is now narrowing the width of the dredge barge and placing the curtain as far from shore as possible so as to minimize damage to this area. Extreme care will be taken in this area and all equipment, auxillary boats, etc. will enter the dredged curtain through the far side. In addition, no work around the road or shoulder above the riprap will minimize the risk of accident or drainage of materials from the silt onto the riprap. 3. Season for dredging Lake Surprise The seasons recommended originally for Lake Surprise dredging were August or October through January. The concept was to minimize dredging and siltation during the spring months when many fisheries food chain organisms might be in planktonic and/or sensitive stages. Plant production of seagrass and epiphytes peak in April -May. When examining data from the nearest well -studied animal community, the Card Sound and Turkey Point project, studies show March, April and May to be a time of maximum abundance of indicator species important to the food web such as Thor floridanus, Hippolytie pleuracantha (Caribbean shrimps) Pagurus bonaerinsis (hermit crab), Neopanope packardii (mud crab) (See Figures 51-57 from Roessler et al 1975, Effects of Thermal Effluents on the Fishes and Benthic Invertebrates of Biscayne Bay, Card Sound, Fla. Technical Report to Dept. of Energy). March, April and May are the time of maximum animal components of plankton bloom and larva development. From mid -June onward, abundances and productivities drop (Figure 51-55) and they increase in September for some species. The seasonality originally suggested - 3- was perhaps too restrictive and mid June through August or October through January could be recommended for an appropriate dredging period. *Reference: Thorhaug, A. et al. 1979. Biological Effects of a Power Plant Thermal Effluent in Card Sound, Fla. Environmental Conservation 6(2): 127-38. RoesB Biscayne Bay from "+ '' 1975 W 14 ru YEARS71 72 7-Z _ rTGUP*E 91. Catch, log (catch +1) of Hinool n pi pccrn��ntha taken to seven tows and twrapsti.�cneu .r G. .,r i ., N I F. S.r t 111.1 -177- Biscayne Bay from Roessler et al, 1975. NEM ±0°C 3 � 1 .►t } t t ti 0 z Sz w -1. A A,(jV - �%A Li SEL .i +3.5°C rn 10 '- 1—JVA ♦ 25'. -. T,_+•ram+t' •;•mow*� +* *#� t '�' �}t+,+�. �t• ��t+/� 0 t i 1��i4•rM�art f� `= +4.5°C 68 69 70 71 M 73 1—t "I) of Thor Eloridanus taken in seven :.:W:4 .lnLl L,,Mpt,1',LLUrt- u[ stations NE II, S II, SE I and C. -1 78— 2f 0 Q U 68 FIGURE 53. Catch, log (catch +l) of Thor Eloridanus taken in seven tons and. temperature at stations 0104, 0504, 0603 and 0604. -179-- Card Sound from Roessler et al_ 1975 45 35 25 15 5 35 25 m 15� m D 5 C CST 55 c� 25 ,5 5 55 '.5 5 5 69 70 71 72 73 Biscayne Bay from Roessler et al. 1975 STATION NE I t 1 '�--' TEMP. +-+CATCH 25 15 1♦++ 0 5 - F 35 rri -SE I 35 M Q i 25 0 15 35 3� 15 N: YEARS . .58 FIGiJR>r 54... Catch, log, (cstah. +1) of Neopanope packardii taken in seven taus and temperature at stations NE I1, F, SE I and G. -181— 20 �Yz G 10 r- Z W 0 `L fa- Y.IQ U Q 2 0 0 O� O Z 10 V +— 0 Q. V ' 0 69 71 Card_ Sound. from Roessler et al.. M 73' FIGURE 55. Catch, log (catch +1) of Neopanope packardii takan in Seven. tows and temperature at stations, 0104, 0504,. 0603 and 0604. =18Z— Biscayne- Bay from Roessler at al 1975 0 10 Z5 rTT 15 m 5 C 35 M 15 5 15 . . r; 1s ss 70 YEARS T'� � FIGMX 56-. catch,. Ios (catch +1) of Pagurua bonaireasis taken is saves torn: and temperature- at stations. N I, S II', SE I and.G. -183— _Z Z 0 0 c 0 v v CL 10 U_ J Cara Sound ; from Roessler et al_ 1975 -� 68 69! 70' 71 72 73 YEARS FICUL 57. Catch, log (catch +l) of Pagums bonairensis taken -in seven toms. and temperature at stations 0104., 0504, 0603 and 0604. -184— 6 APPENDIX "E" - ITEM 8 WATER SUPPLY AND TRANSMISSION MAIN FLORIDA KEYS AQUEDUCT AUTHORITY, FLORIDA • MONROE COUNTY PROPERTY OWNERS: "%OWDA S4 ' �.. N'T� �Ir ONR01� C!•:A lYlOVYTY ROPRTY .t1YPRA13RR COUHTT COYaTHOUSC P.0. WK Iit$ KCV wail. rLCMICA aat+o CTA awoac cats• :aasau ERVIN A. HIGM C.F.A. February 13, 1980 Greenleaf and Telesca, Inc. 2650 S.W. 27th Ave. Miami, F1 33133 ATTENTION: Mr. August* Perez Dear Mr. Perez: In regard to our recent telephone conversation, please find enclosed a list of owners adjacent to U.S. Highway 1, north from Dixie Highway to Dade County line, in Monroe County as requested. Sincerely, ERVIN A. HIGGS, C.F.A. COUNTY PROPERTY APPRAISER EAH/SG/jlk Enclosure MONROE COUNTY PR-. -... Y OWNERS: , Lippman, Milton A. i Michael A. Abels %234 N. KromL Ave. Homestead, F1 33030 Lake Surprise Estates Key Largo PB4-162 Lot 33, Blk. 14 OR 596-428, OR 762-821-822, OR 744,701,702 OR 789-1-2 • Lippman, Milton A. i Michael A. Abels %234 N. Srome Ave. Homestead, F1 33030 Lake Surprise Estates Key Largo PB4-162 Lot 34, Blk. 14 OR596-428, OR762-821-822, OR774-701-702, OR789-1-2 • Lippman, Hilton A. i Michael A. Abels 14600 SW 74th Ct. Miami, F1 33158 Lake Surprise Estates Key Largo PB4-162 Lot 35, Blk. 14 011179-98, OR372-209, OR734-709, OR794-454 • Ifebb, Rita McCooms 9241 S11 117th Ave. Miami, PI 33286 Lake Surprise Estates Rey Largo PB4-162 Lot 36. Blk. 14 OR179-98, OR372-209, OR774-295 • Webb, Frances 9241 Sci 117th Ave. N.iami, Fl 33186 Lake Surprise Estates Key Largo PB4-162 Lot 37, Blk. 14 OR474-621 • Lake Surprise Estates, Inc. %Charles Kinsell 1210 S. Alhambra Cir. Coral Gables, Fl 33146 Lake Surprise Estates Key Largo PB4-162 Lot 38, alk. 14 OR179-98, OR372-209 9 Lake Surprise Estates, Inc. %Charles Kinsell 1110 S. Alhambra Cir. Coral Gables, F1 33146 Lake Surprise Estates Kay Largo PB4-162 Lot 39, Blk. 14 OR179-98, OR372-209 • Clark, Oscar Peter 2100 Sans Souci Blvd. Apt. 1503 N. Miami, F1 33161 Lake Surprise Estates Key Largo PB4-162 Lot 40, Blk. 14 OR424-832 • Clark, Oscar Peter 2100 Sans Souci Blvd. Apt. 1503 N. Miami, F1 33161 Lake Surprise Estates Key Largo PB4-162, Lot 41, Blk. 14 OR424-832 • S. Dade Baptist Church %Key Largo Baptist Temple P.O. Box 971 Key Largo, F1 33037 Lake Surprise Estates Key Largo PB4-162 Lot 42, Blk. 14 OR625-51, Or..625-52, OR631-3690 {t U Totem of Miami, Inc. IL. B. Walker i Assoc. 546 The Main Bldg. Houston, Texas 77002 City of Key Largo PB3-155 Rev. Plat of Blk. 5 Plat t5 Key Largo City, Key Largo PB3-155 ORS49-1026/1031, OR608-536E • Morris, Benjamin W. etux P.O. Box 566 Homestead, F1 33030 Monroe Park, PB3-140 Cross Key, Tract A 9 Bowden, Mildred H. 4167 Mogadore Rd. Kent, Oh 44240 i Monroe Park, PB3-140 Cross Key, Tract S OR326-478-479 Moorings -Marina, Inc. The ' Suite 521 7220 NW 36th St., Miami, F1 33166 Monroe Park, P93-140, Cross Key Tract C, OR327-467-468, 011717-364 OR772-1371E, OR796-30 Leach, Jeannette M. 1020 SW 22 St. Miami, F1 33129 Lake Suprise Estates Key Largo PB4-162 Lot 26, Blk. 14 OR 587-826 Leach, Jeannette M. 1020 SW 22 St. Miami, F1 33129 Lake Surprise Estates Key Largo P84-162 Lot 27, Blk. 14 OR 587-827 • Gross, Joseph etux 2220 SW 100th Ave. Miami, F1 33165 Lake Surprise Estates Key Largo PB4-162 Lot 28, Blk. 14 OR 422-849 a Booth, Clyde i Bertha 28700 S. Old Dixie Hwy. Homestead, Fl 33030 Lake Surprise Estates Key Largo P84-162 Lot 29, Blk. 14 OR 568-228 • Munroe, Esther Lee P.O. Box 1426 Key Largo, Fl 33037 Lake Surprise Estates Key Largo PB4-162 Lot 30, Blk. 14 OR 179-98, OR 372-209, OR 689-233 OR 767-862 Lippman, Milton A. i Michael A. Abels %234 N. !crone Ave. Homestead, F1 33030 Lake Surprise Estates Key Largo PB4-162 Lot 31, Blk. 14 OR 596-428, OR 762-821-822, OR 774-701-702 OR 789-1-2 e Lippman, Milton A. i Michael A. Abels %234 H. Krone Ave. Homestead, Fl 33030 Lake Surprise Estates Key Largo P84-162 Lot 32, Blk. 14 OR 596-428, OR 762-821-822, OR 774-701-702 OR 789-1-2 MONROE CuuivTY Pn`'''�DT"�°iii��icS: J• So. Bell Tel & Tel. Co. Tax Adm. Office Bf-C 2211, Atlanta, Ga 30301 4 . 31-60-40 A60031-09 Island of Key Largo Pt. Lot 11, PS1-68, G 63-268-270 G 63-265-266, OR281-541-542 • Sweeting, Ruth T. P.O. Box 978 Winter Haven, F1 33880 . 31-60-40 A60031-10 Island of Key Largo Pt. Lots 5-6 UW of 11/W PB1-68, G42-85 G70-369-379 • Largo -Brand Corp. 9200 S. Dadeland Blvd. Suite 600 Miami, F1 33156 31-60-40 A60031-12 Island of Key Largo Pt. Lots 1-2-3-4-6-7-10 lying E'ly RR PB1-68, ORS66-942 • Rubenfeld, Joseph 118E 60th St. New York, NY 10022 31-60-40 A60031-15 Island of Key Largo Pt. Lots 6-7 lying E'ly of RR OR531-843 OR669-64/66 • Fla Keys'Electric Coop Assoc,, Inc. General Delivery Tavernier, F1 33070 4-60-39 A60904-01 Pt. SE 1/4 lying E'ly of H/V1 1, OP.320-510 • McKay J. G. Jr., Trustee %Mighty Mite Controls, Inc. 44 N. Summit St. Okron, Oh 44308 25/36-60-39 A60925-01 Island of Key Largo PBS-11, Tract of low mangrove OR403-841 • City National Bank of Miami Beach Miami Beach, F1 33139 25-60-39 A60925-02 Tract of Sovereign Land Cross Key OR224-516-518, OR297-77-78 OR298-567, OR376-534-535, OR460-485-492 • Kinsell, Charles J. Jr., etux 1110 S. Alhambra Circle Coral Gables, F1 33134 36-60-39 A60936-01 Island of Key Largo Pt. fractional OR386-697/701 • Blackwater'Sound Properties, Inc. %Alton R. Wells 44 N. Summitt St. Akron, Oh 44308 36-60-39 A60936-02 Key Largo Pt. fractional OR373-194-196 • Key Largo Associates, Inc. Box 218 Key Largo, Fj 33037 36-60-39 A60936-03 Pt. NE 1/4 of NW 1/4 OR83-617-618 • Csont, Ernest, etux Rt. 1, Box 272-A 36-60-39 Pt. NE 1/4 of N11 1/4 OR544-625 Key Largo, F1 33037 • Gunn, James i Lynette Rt. 1, Box 273 Key Largo, F1 33037 36-60-39 A60936-04.1, PT. NE 1/4 of NW 1/4 G57-215-216, C57-217-218, OR243-169 0R658-226, OR758-1620 • S. Dade Baptist Church •Key Largo Baptist Temple P.O. Box 971 Key Largo, F1 33037 Lake Surprise Estates Key Largo PB4-162 Lot 43, 31k. 14 OR625-51, OR625-52, OR631-3690 • S. Dade Baptist Church %Key Largo Baptist Temple P.O. Box 971 Key Largo, F1 33037 Lake Surprise Estates Key Largo PB4-162 Lot 44, Blk. 14 OR625-49, OR631-369Q • S. Dade Baptist Church %Key -cargo Baptist Temple P.O. Box 971 Key Largo, F1 33037 Lake Surprise Estates Key Largo P84-162 Lot 45, Blk. 14 OR625-49, OR631-3690 • S. Dade Baptist Church %Key Largo Baptist Temple P.O. Box 971 Key Largo, F1 33037 Lake Surprise Estates Key Largo PB4-162 Lot 46, Blk. 14 OR 625-51, OR 625-52 • Perosino, Raymond V. L Denise 10353 SW 115th St. Miami, Fl 33156 Lake Surprise Estates Key Largo PB4-162 Lot 47, Blk. 14 OR 555-921 • Boyd P. H. Jr. i Joann P.O. Box 243 Homestead, F1 33030 Lake Surprise Estates Key Largo PB4-162 OR 553-518, OR 553-519, OR $53-520 Lot 48, Blk. 14 • Lovett, Rachel Havener 1131 Sunset Dr. Coral Gables, F1 33143 Lake Surprise Estates Key Largo PB4-162 Lot 49, Blk. 14 OR 371-489-490, 01% 799-2169 Lovett, Rachel Havener 1121 Sunset Dr. Coral Gables, F1 33143 Lake Surprise Estates Key Largo PB4-162 Lot 50, Blk. 14 OR 179-99, OR 372-209, OR 799-2170 :Nautical Center, Inc. 424 Sunmerland Rd. Key Largo, F1 33037 Lake Surprise Estates Key Largo PB4-162 Lot 51, Blk. 14 OR 179-99, OR 372-209, OR 651-37, OR 752-1781 • Nautical Center, Inc. 424 Summerland Rd. Key Largo, Fl 33037 Lake Surprise Estates Key Largo PB4-162 Lot 52, Blk. 14 OR 179-99. OR 372-209, OR 651-37, OR 752-1781