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LIST OF PARTIES TO I'ESTIFY AT MIIAMII CANAL LOCK HEARiING TO BE HELD JUTLY 11, 1946 Vice-Chairmian -of the Board of' County Comniesioners: and acting for the chairman who is out of tus oity. County Engineer for Dade County, Florida. Attorney for Board of County Commissioners. Consulting Engineer for Dade County's Water Control Progran. Dade County Water Control -Engineer Geologist, U. S. Geological Survey, in charge of ground water resources investigations in Southeastern Florida Associate Engineer in charge of Surface W~ater Division of U. S. Geological Survey in Southeastern Florida Director of the Department of Wlater and Sewers Sfor the City of Miand.. (Will present report by Mualcolm Pirnie, outstanding authority on TEMPT YMERR~i ~ matters. ) Resident Engineer for Day and Zimmnenaman, Consulting Engineers, assigned to the City of M~iamni Department of Wlater and Sewers. Health Cammissioner for Dade County. President of Board of Commnissioners, Everglades Drainage Distriot, and large property owner ia Northw~est Dade County. Engineer for Board of Commissioners of Everglades Drainage District S Physician, early settler, large acale farmer, large scale dairyman and President of the Little River Valley Drainage Distriot. RlD N oted Horticulturist, plant explorer and University of Miani professor. Early settler and President of the Florida Wdell Drillers Association. 1. $ HUGE PETERS 2. rEA31E M. RADER 3. PARK; CAIWPBELL 4. J THEIODORE KNAPPEN 5. JOHN C. 829IERNS 6. GERALD G. PARKER 7. DEAN B. BOGART 8. J W. A. GLASS 9. v' C. F. WER~TZ .0. 4 DR. T. E. CATO L1, DEWpEY RILSABECK 12. LARABR JOHNSON 13, DR. JOEN G. DUPUIE L4, DR. JOHN C. GIFFOI L5. JOHN HURST -1- .B. H. GALLATIN Soil Scientist, U. 8. Department of Agricultgr~e. (Will present a statement by Dr. Geo. B. Ruhle, Plant Pathologist with the University of Florida Agricultural Experimental Station in charge of sub-tropical Experimental Station, Homestead, Fla.) Soil Chemist of the University of Florida Agricultural Experimental Station and in charge of the Evergladea Experime~ntal Station, Belle Glrade, Florida Noted author and representative of Dade County CGonser-vation Council and Miami Rod and Reel Club Vice-Presidenrt of Florida W~ild Life Federation. DR. R. V. ALLISON EUSTACE L. ADAME S JAMES OBER .19. RESOLUTION BY BOARD OF COMEBISSIONEERS, EtVERGLADES DRAINAGE DISTRICT 'BHEREAS, the BOARD OF COUNTY COMMISSIONERS OF DADE COUNTY, as and constituting the WATER CONSERVATION DISTRICT OF DADE COURTY, FLORIDA, has applied to the W~ar Department for per- mission to construct a water control dan with navigation looks in the MIliami Canal; and WHEREAS, EVERGLADES DRAINaAGE DISTRICT is charged by law writh the responsibility of regulating the water levels, anal stages and the outlet capacity of canals within said Distriot, for the purposes of agriculture, sanitation and for the public utility and benefit; and HEBEREA$S, THlE BOARD OF COMMeISSIONERS OF EVERGLADES DRAIN- AGE DISTRICT has considered the design and plans of the structure proposed and is satisfied that said design and plans provide for an adequate regulation of canal tages and the discharge of flood wuraters; and that they are further assured that the structure will contribute to the general betterment of water control conditions, including prevention of the intrusion of salt wa~Kters. NOW, THlEREFORE, BE IT RESOLVED 14r the BOARD OF COMMI~IS- SIONERS OF EVERGLADZES DRAINAGE DISTRICT,ab a regular meeting held in West Palm Beach, Florida, on July 5, 1946, that the War Departi- ment be, and is hereby, requested to grant the request of the BOARD OF COMMISSIONERS OF DADE COUNTY as and constituting the WAlTER CONSERVATIION DISTRICT OF DADE COUNTY, FLORIDAB, for permission to construct the said rnater control dom in the Miami Canal, and does assure the iear Department that the granting; of such request is not La conflict wpith the plans of EVERGLADES DRAINA~GE DIS.TRICT or its legal rights and interests in the promises. BE IT FRTHEBR BESOLVED, that nothing contained in this Resoluti'on relinquishes or warives any statutory duty or authority of the EVERGLADE~S DRAINAGE DISTRICT. STATE OF FLORIDA COUNTY OF PALM6 BEACH) I, K. M. THROOP, Secretary, hereby certify that the above and foregoing is a true and correct copy of an excerpt from the minutes of a meeting of the BOARD OF COMMIBISSIONSERS OF EVERGLADES DRAINABGE DISTRICT held at West Palma Beach, Florida, on July 5, 194-6. WVITNESS my signature and official seal of the ~EVER- GLADES DRAIN3AGE DISTRICT at West Palm Beach, in the County of Palm Beach, and State of Florida, thia 8th day of July, 1946. (Signed) K. M. Throop Secretary, BOARD OF COBIMISSIONERS OF EVERGLADEiS DRINBBAGE DISTRICT Presentation at U. S. Engineer office hearing July 11, 1946 on permit to construct look and dam in Miarni River at NfW 20th Street, Miamd. Extent and Nature of Intrusion of Salty Water in Canals in Southeastern Florida As already described to you salt water contamination of the ground water concentrically with the inner coast of Southeastern Florida and along ~the tidal canals was a direct result of drainage operations and associated lowering of the fresh water table. Tongues of salty water moved up the canals and caused contaminattion far in advance of the slower basic intrusion. It was a relatively swift action and varied in extent fran year to year seasonally. The contamination of oanals in some degree by salty sea water occurred prior to 1939 but it was then that the situation in Miaai Canal indicated the need for iatensivy~ study and possible remedy. Excessively saline water was found in Miami Canal, then not controlled, itearly 11 miles fran Biscayne Bay or about 3 miles west of the annicipal well field. It was in this ~period that a number of the wells were rendered useless as sources of drinking water. Since 1943, sea water has been prevented from proceeding farther up Miami Canal than Hialesh by temporary dama near 36th Street, Miami. There is little doubt that these dams prevented the intrusion fran extending many miles farther inland. The large rook pits in the lower Miiami arnd Tamiami basins, however, were outside of the protection of the dams and became strongly~ salty. Following a series of dry years, the situation became extreme in the spring and summer of 1945 as anal and ground water levels declined to wrhat were possibly all-time lows. In the then uncontrolled Little River and Biscayne Canals strongly salty water existed throughout their entire lengths. W8hater with a salt concentration of about 75j4 of that of sea water was seen running into the porouis ground at the western ends of the canals, It did not go farther by oanal only because the bottan of Ried Road Canal and its laterals was slightly higher than the salty wNater in the tidal larger canals. In 1945 salty water penetrated west of Florida H~ighway 149 in. Snake Greek Canal, despite its.weed and debris choked condition. In Tasniami Canal excessive salinity waes found at the WIest Flagler Street bridge. Salty water went most of F. E. C. Railway (inland branch) in Coral Gables Canal; past U. S. Highway 1 in Snapper Creek Canal* In the Homestead-Florida City area all of the uncontrolled and partially controlled canals were heavily saline throughout with many of the lateral ditches contaminated. Concentrations were ia somea places 20 to 30 percent higher than that of normal sea water, due to evaporation. Along the affected canals reports wnere receivedlabout soil and water made unfit fTor agricultural, commercial, and domestic use. Sea water moves in a canal as affected by tidal variations and fresh water rnuorff As the amount of fresh water coming down a canal decreases the salt inter in the bay or ocean begins to move inland. It proceeds in an alternately advancing and retreating action under influence of the tides and it lays in the lower -part of the canal under the fresh water. Sea water in this area has a specific gravity as high as 1.03 and in a canal exists as ea density current. At tians there is fresh water running toward the Page 2. aea in the upper part of the canal and salty water running inid~nd beneath it, with a considerable velocity in both directions and no appreciable transition zone betweedthe tw~o layers. The inland trend continues as the amount of fresh water coming from the back country decreases. Sonewhere along the canal a point is con- tinuously reached where the effect of the fresh water runoff equals the effect of the inland moving salty water. And when the level in the canal declines nearly to that in the sea, the rate of intrusion is accelerated and that portion of the canal becomes quickly contami~na-ted. Under these conditions the whole cross-section of the canal becomes salty and there is no separation between the two kinds of waater. Sdc~h occurred in 1945 with resultant pouring of salty water into the porous formations along the canals. It hars been observed that within a month or so, with heavy rainfall, it is possible for conditions in the canals to become entirely reversed with freds water forcing the salty water back toward the sea. The canals then become comparatively uncontaminated except in the lower reaches of the larger ones. But the salty water in the ground does not dissipate so quickly and remains to cause possible trouble. And the rock -pits do ' not become fresh because the entrances are considerably above the bottoms and the heavier salty water cannot escape down the canals. The pits have in the last several years remained salty during~ the wet seasons. It should be pointed out that in any year of sounty rainfall and with uncontrolled canals extreme intrusion of salty water own occur. Page 3. But the experience of the recent dry a eason indicates that intrusion can be halted in the canals. The various temporary salt barriers con- structed this yrear in the Miami area have been entirely effective in stopping contamination in the canals. For the protection of the fresh, water it is desirable that such controls. be placed as far downstream as feasible and that the upstream levels be kept as high as practicable. July 9, 1946 Dean B. Bogart Associate Enginsee 11. B. Geological Survey Miami, Florida Page 4. 00PY July 10, 1946 I am Djr. T. E. Cato, Director of the Dade County Health Unit which is the Deparhnent of Publio Kealth for the City of Mdiarpi, MSiami Beach, Coral Gables, and all of Dade County. Certain special interests in M8iamd have opposed the construc- tion of a look in the fidiadn river. In order to block the cons~true- tion of this look and force the removal of the well fields to the evrerglades, these people have not confined their opposition to econeksic and legitimate grounds. They have, unfortunately, attempted to cause fear in the minds of the people of Miandi concerning the purity of their water supply now, and after the dambhas been com- pleted. The purity of water is something that can be measured as easily as the put~ity of gold or- silver can be determined. There is no question as to the amount of silver in a silver dollar because it is a matter of record and is easily determined. There is no question as to the purity of M8iami s water because it is a matter of record and is easily detennined. The construction of a dam in the Miami river will not cause pollution of M~iami's water supply. There will still be the same depth of sand and rock that the water necessarily must filter through before it reaches the wells, and the raising of the 9eater level will not influence the amount of sand through which this water must filter. There are definite standards for drinking water that. have been established by the Federal Government. M-iani~s re wager supply more than meets these standards. The people of Mdiami own es~t assured that they have a pure and safe water supply~ and that they will have a pure and safe water supply after the dan has been constructed. In conelusion I will say that the City of Mliami's water supply well field` is niot polluted and will not bie polluted to the future because the Dade' County Health Unit through the exercise of its regulations and police power will see to it that it does not became polluted. Respectfully submitted, (Signed) T. E. Cato T. E. Cato, MD. TEC: ah Eealth Canmis sioner AGRICULTURAL EP~ERIMBENT STATIONS Everglades Exrperiment Station Belle Glade, Florida Colonel A. B. Joness Distriot Engineer U. S. Engineer Office Jacksonvilles Florida Re: Soil and Water Conservation in Relation to Miami River Improve- ment . In considering the problem of soil and water conservation ia the Everglades there frequently comes to adnd the terms with which I once- heard Mr.' Arthur E. Mlorgan, when Chairman of the Tennessee Valley authority, characterize our national wastefulness and profligacy in the handling of our phosphate resources while discussing this subject in a regional conference in Chattanooga back in 1936. Naturally the impression made by his remarks was considerably enlarged and extended when in the course of a later review of this samne subject at the University of Florida in Gaineaville, Dootor Mdorgan, former President of the University of Tennessee and immediate suooessor of A, E. Mlorg~an as Chairman of the Tennessee Valley Authority, used preciselyT the samle words and essentially the same vehemence in setting forth his own equally deep feelings of despair in the matter. Whtat both of these gentlemen said in classifying and characterizing the retributions to come~ was that FUTURE GENERAITIONS WrLL RISE UP AN~D SPEAR OUR G~RAVES....."n Now I suspect that if I were to undertake to discuss the terrifying waste and economic losses of the past in handling our soil and water re- sources of the Everglades in these same general terms some of us would Col. Jones, page 2 have plenty of cause to anticipate that our graves would not only be speared again and agaia but that those spears. even would be waggled around until they do actually find us. There can be no doubt in the mind of anyone who has critically examined the situation that the soil resources of the Evergladea have been most miserably punished in the past, especially through the inade- quate handling of the natural water supply by which they should be pro- teeted. This has been due in large part, of courses to lack of equipment and personnel for the purpose. Thus it largely boils down to ~the inadequacy of the reolanation plans that have been developed in the past, especially from the standpoint of water conservation ani all that it stands for in terms of soil conservation, municipal water supply, wild life protection and development, availability of irrigation water sual the possible amelio- ration of winter temperatures, to-mention only a few benefits. Wiith the above facts in mind I wgish to include in the record of this heartag a copy of Volume V-A of the Proceediags of the Soil Science Society of Florida which is a complete and comprehensive report on a special, interim meeting of the Society held in Belle Glade in March of 1943 for a careful discussion of the physical and economic problems of this great area. In this volume are to be found numerous papers that treat in con- siderable detail of the relationships existing between geological and climatological factors in the formation of these~ soils and of their practi- cal use limitations at the present time. In viewP of the availability of this information in this frorm I shall include with the present discussion as exhibitam;only a limited number of photographs selected largely fras the field trip reported on pages177-187, inluelssives ia the appendix at 001. Jones, page.5 the baick. These will serve to show the intimate and inseparable relations of the water probDlems of the. whole area to those of 'the Southeastern section thereof, which is thei principDal area under discussion in this hearing. Thus, Exhibita II, III and IP as located on1 the myp of Exhibit I, clearly, ahow the ~importance of the~ subsidence factor in the handling' of peavt and muano soils and the manner in which water can be: co~ntrolled even in our main 6asuals while Exhibit V illustrates the great firesa that have swept the whole area, time and ~agaia, when the water table has been per- mi~tted to fall so low as to fail in the natural protection such soiled must have from this. source if they a~re to survive even a reasonable period. of use. Incidentally the fire in the lower picture of Exhibit Vi is in the open area to the north an~d west of PennTSUCO where extensive. areas of the shallow peat have been burned practically to the underlying rook except, of course, in the deeper potholes. The topographic map of Exhibit VI, the soil map of Exghioit VII, the geological maps of Exchibits VIII and II and the man showing the approximate direction of surface flow in Exhibit I are all helpful ~in indicating the general trend of surface elevation fron nor a tot south, the very important change in -typtpe iand depth of organic soils as one progressed southwards in the direction of the Yiami area, and the type tadd distribution of the underlying rook wrhich is proving such an important factor from the water control standp oint. Ech'Fibits II and III display in still greater detail the distribution and character of. the MBiani. Oolite and other highly porous lime rookss to that section that shall doubtless find suchi an important place. in this he'aning. A a ma-tter of fact it wculd seem logical to believe that the leakyr floor in Col. Jones, page 4 this aeotion of the Glades is quite appreciably accountable for the shallow depths of the original organic mantle to the south since it places the formation of peat under suda conditions in somewhat the same position younor I would find ourselves if wre were to undertake the processing of sauerkraut in a barrel with its bottom full of holes. There can be no question that this conservation approach has very definitely assisted in the development of a broader understanding of the whole Everglades problem during the past few years, as has also the cordial and helpful cooperation which the Officials of the U. 8. Engineer Office have so consistently given us whenever it has been found consistent with the responsibility of their office to do so. It must be emphasized, however, that to the extent our understanding of the whole problem has become more clearly defined to that same extent has our appreciation been heightened that the general pattern is mnade up of a large Ilnrmber of individual problems which always must be treated in their relation to each other and to the adaole project if a return to the confusion of the past is to be avoided. Thus the question of how best to handle the local water supply that is under discussion here today is truly typical of one of those local problems and I sincerely trust that its consideration as a problem separate and apart; from the whole will not be indulged in. any way at any time. Thus when a resolution was moved io the course of the Belle Glade meeting of the Soil Science Society of Florida back in 1943 that con- tained as its very heart the request "That the Everglades Drainage District .... assume responsibility for the development of an OVER-ALL POLICY AND PLAN~- for the future conservation and development of the land Col. Jones, page 5 and water resources of the Everglades and ,.... serve as the CENTRAL AUTLIORITY to coordinate the activities of all private and governmental agencies in the execution of such plan" it represented quite a far ory from the approach thd; had prevailed up to that time, as MVr. Mdark R. Tennant, the Chairman of the Everglades Board at that time, will tell you. It is significant, too, that the resolution also asked thatt Ever- glades Drainage District arrange a joint; meeting with the Trustees of the Internal Im~provement Fund and State Officials in Tallahassee to be attended by representatives of all interested agencies to discuss matters of policy and the steps to be taken towards the adoption of a plan and Establishment of the Distriot as the~ required CENTRAL AUTRORITY". Such a meeting was held about a month later (April 1943) in Ta~llhassee under the general Chairmanship of Governor Holland and with the particular assistance of Cannmissioner Mayo end Mfr. Tennant. The real significance of that part of the resolution stems fran the fact that the Tallahassee meeting proved a tremendous souzrce of inspiration for each and every one of the eighty or more who attended including, I believes no one quite so anoh as the Governor himself. For there could be no greater harmony of thought or unanimity of opinion than prevailed in that meeting when the question of centralizing authority over Everglades affairs to the Board of Commnissioners of the Everyglades Drainage D~istr~iot was definitely brought forward. The entire group, to the very last member of the Cabinet, was entirely favorable to the proposition and Governor Holland closed the meeting by turning the decision over to the Everglades Board essentially as a mandate and urging that the de-tails be worked out as rapidly as possible. Col. Jones, page 6 While the progress of this conversion to such a broadly different basis of operation on the part of the Boards due, among; other things, to lack of funds for essential operations, has not been so rapid as to dazzle, it assuredly has been steady, straightforward and substantial. That real advances have been made is well indicated, for instance, when responsibility and authority for the construction and operation of all works and installations within the Distriot, once they are approved by the Board, was recently turned over to its Chief Engineer. Perhaps an even better indication of the change that is taking place is to be found in the manner in which Dade County Authorities have worked with the Everglades District Board and its Engineer in developing the plea and design for the Miardi River structure nowp under discussion which will assume such an important role in one of the Distriots principal outlets in this section of the Everglades if and whnen it is constructed; for such harmony in the planning of such important local facilities oan not but develop the hope that coordination and cooperation in the whole plan of construction and of operation of the facilities at the Distriot, for which we have waited so long, may be in the process of development. As a matter of fact, Colonel Jones, if the report of your findings proves favorable to the development of this control in the Mlised River and it is constructed and operated under the joint supervision of County and District Authorities to the very best interest of the several purposes which it can so effectively s erve rather than for any particular interest to the disproportionate detrimoent of one or more of the others then I can see in this hearing one of the really great moments in the life of the Col. Jones, page 7 Everglades or at least in the life and future of that portion of it which is still left to us. In closing I would like to reenqphasize ~briefly, but just as' seriously as possible, the principal point I have tried to bring out in this discussion namely,- the importance of water conservation in and on the land for a number of purposes but above all else the protection of -th2e land itself. A fact that too few people realize, at least so it seems to mei, is that the monetary values we attadb to the soil and to the land are for purposes of barter only and do not, in any real sense of the word, repre- sent absolute or net values. For the soil by which wre live is, ia the broader sense of the wrord, -above, and beyond value mruch the same as human life. Unfortunately we too frequently realize this only after it is seriously impaired or hopelessly destroyed. Pfhile we may endure a certain amount of damage to it, locally for a time, it is, nevertheless, always dangerous for we know from history that when the land of a Nation is beaten down and destroyed then that Nation, as a Nation, also is dead. The same is trues of course, for local areas 'insofar as agriculture is concerned. It is on this account that I have repeatedly asked myself and am now asking you the very poignant question "Wh~ere is the agriculture of the ~Everglades going when the Glades no longer can be farmed?"\ For this youn must understand, is not merely a question in parasing but one. that is based fairly and squarely on the recorded subsidence of these organic soils. This trend is especially critical, of course, in the main aseotions d' 41e Everglades where the organic mantle is ~directly underlain by line rock. This rate of subsidence is well shown in Exhibjit IIII and is inf'luencetd directly by (1) depth to water table and (2) amount and character of owlti- 001. Jones, page 8 vation. It is not difficult to imagine that quite aside fron the great fires that raged over the Everglades in 1943, when the water fe~llso liow, even in the central Gladess that the table. was in the roock itself, where the muck was 5 feet or more deep, taat this was the most brutal treatment that possibly could be given thia lands for enormous losses by shrinkage and oxidation were caused thfereby quite aside, it should be emrphasizeds fran the actual burning which it sustained as a result of those conditions. among the salient facts relating to the handling of water that we must ~eep in mdnd as the basis for the most constructive system of recla- mation we can possibly develop for the Everglades or for any section of it;, the following, to my way of thinking stand out as particularly imp~ortanst: (1)~ TIhe total water supply coming to the Everglades area, of to Iany section of it, actually provides little for wasting. If the needs are fully recognized and are to be even reasonably well satisfied, conserva- tion must be the wa~tchword. (2) The water conservation viewpoint must be kept irrevocably geared to the job or jobs that water anat do with a strict avoidance of partiality if a well balanced result is to be attained. Soil conservation, municipal. water supply, w~ild life protection and development, irri gation and amelioration of winter temperatures are among the jobs which only water can do, any one of which however, is worthy of practically any amount of effort required for its attainment. (3) Finally, we must keep in mind that (A) regardless of local soil values, carefully planned water reserve areas are an utterly indispens~ible Col. Jones, page 9 part of a successful waster control system for such a low-lying, flatland area as the Everglades; (B) if storage areas are not planned for water in times of abundance or excess, muld well organized facilities available for delivering it to these areas, then the surplus largely will be dissi- pated, as in the past; (0) notwithstanding the availability of disposal facilities for whatever purpose and to whatever places, flash flood con- ditions can not be cared for with sufficient promptness, in a great flat- land area. such as we have to deal with, without doing appreciable damage; but that (D) a flood is always of much less permanent damage to the land than a fire especially if plans have been made and facilities prepared in advance to store just as much of the surplus water as possible for future protection against the time it definitely will be needed for one or more, if not all, of the highly worth-while purposes~ listed above. If the structure in question is installed in the Miami River and operated in the interest of maintaining water reserves in the open Glades in the interest of soil conservation, wild life protection and development, irrigation and the amelioration of winter temperatures it is sincerely believed that this facility will be found an economic benefit even aside fran its very great value to the municipal water supply of Greater Miand which is certain to increase at a great .ra~te in the years to comes that is if the naturally e expanding requirement for water io this area is not itself prevented by the shortcomings of the manner in which the problem of future supply is handled. Everglades Experiment Station Belle Glades Florida July 11, 1946 FAIRCHILD TROPICAL GARDEN in Coral Gables Box 407 Coconut Grove, Fla. National Geographic Society Wjashington, D. C. July 2nd, 1946 Col. A. B. Jones District Engineer U. S. Engineer's Office Jacksonville, Florida Dear Colonel Jones: It would have been a pleasure to meet you and discuss the salt water seepage control question. It is too important, fraught with too great dangers to a growing community to be settled in an ordinary way by people coming to the committee table ai~th prejudices, personal or official, and using their influence to spring the decision their way. The question of who will benefit immediately or who be hurt immediately by the decision, will look small after a few years have passed. I come into the discussion as a Federal DepartmentC of Agriculture Expert on Tropical Plants, one wh~o has watched the growth in this region of thousands of introduced plants from all over the Tropies. I had charge of the organization of the Federal Office of Plant Introduction in Wiashington and through it brought in thousands of new and valuable plants from Tropical. and Sub-tropical regions. These were grown and tested here and later distributed to the residents of this whole area. In 1898 a Plant Introduction Gardenwvas established, wPhen Miami was a small village and no-thing much was known about conditions for growing plants here, except the remarkable fact that a fewa feet below the surface of the ground there was an inexhaustible supply of fresh water, It was myr busi- ness to study the conditions required by the newr crops so as to fit than into -2- the agriculture which was growing up about the little twnm. The town has grown enormously -- the Government Introduction Garden has been removed from a little six sore tract to one of approximately eight hundred acres and the Government monies spent on it increased in proportion. Today there exists nowvhere else ia the Western Hemisphere such a collection of authenticated foreign econonio plants as that ia the Government Garden in Chapman Field; even devastated as it was by the storm of Septenber last. The records of observations pertaining to these plants cannot be equalled outside of the great gardens of Geylon and Java. This work has gone on in spite of all the discouragements that have been occasioned by the freezes, hurricanes, and drouthe which have visited the M8iami region. The Garden now is slowly recovering from its worst oatastrophy, the September Hurricane of 1945. These climatic difficulties were not at first anticipated, but we not then, and such plants as could stand up against them have been increased and have become Naew Industries here. I have only to cite the Avocado and Mdango industries as examples and the Cattle industrywas contributed to substantially through the introduction of the Para grass and other grasses ad legumes. Now to discover after half a century of work and the expenditure of a considerable sun of moneys that the drattage of the Everglades, inwhich many of the residents came to believe turns out to be fraught with perils to our plants is to say the least mosbdisturbing;. Through the years since 1898 home owners here have boasted of having below their gardens and groves .perpetually flowing fresh water; -- in our favor as against the strongly alkaline, oalcareous, sandy and rooky soils. We banked on this fresh water that crept upward in the rooks and prevented the drouths fran killing the trees. Because of these conditions, which we had a right to believe were perman- nent, the real estate dealers used the fact in good faith as advertising and induced thousands of people to buy their homes and gardens in this "paradise"; this tropical garden spot around Miani and test stretches along the coast. Had it been predicted that the shallow wells they drove in their gardens would turn salty and the water from them kill their trees and plants, many of them would not have bought the land at all but gone elsewhere and made their hones. Now, they cam say with fairness, I think, that they were deceived, bought hanes under false pretenses an~d have a right to demand that the County do everyr- thing in its power to protect their gardens from a danger that was' brought about by the enthusiastic engineers who did not foresee this seepage effect which has cone upon them. Fran freezse and hurricanes and drouths, no human power has yet devised adequate protection but against this new menace they may be protected. Engineers who have studied the problem carefully say something can be done by controlling the water flowP in the canals. Nobody can see the future any more than he can see his hand before his face on a pitch dark night. But Soience has furnished a most amazing new body of knowledge to the engineers and soil chemists of today, knowledge that the anal diggers of twro decades ago did not dream of. If theyr say "Let us try and prevent this seepage of salt water into the porous rooks underlying your gardena" I believe they should be given a free hand. If they fail, and the-salt continues to invade our garden soils, one thing can be predicted, because it rests on the knowledge of the effects of salt on plant roots and the physics of its behaviour in porous rookest :birh now well known phenomena. The beautiful tropical vegetation around our dwellings will be reduced to the few species that can stand salt water, and much of the charm that our residents came here to enjoy will be gone. The intellectual and artistic people who should give a high character to our life here may go elsewhere. Just across the Caribbean lie places of superb charn and surpassing beauty. They may go there. Those real estate people in the North who have been jealous of Miiami's climate and its growth may urge their clients to go and build their gardens and orchards where the soil is not becoming * salty -- across to Central and South America. The question of salt water seepage in our garden soils and its rise to the roots of our orchard trees has a direct bearing on the possibility of Miiani being by-passed by the thousands who want garden homes beyond the region of cold weather. Wihat is the use of the University of M~iami with its program of developing a Department of Tropical Forestry and Econ~omic Tropical Horticulture; wrh~t is the use of nakring; a great collection of palms in the Fairchild Tropical Garden if the land in this area is to~ be allowed to become unfitted for the growth of tropical plants. The despoiling of Florida's finest forest scenery has gone very far already. M~ay this salt seepage not ruin the tropical gardens which are swinging into existence here. Very sincerely yours (Signed) David Fairohild David Fairchild Mby name is M~elvin E. Gallatin. I an a Soil Scientist, employed by the U. S. Department of Agriculture Soil Conservation Service in cooperation with the Sub-Tropical Experiment Station of the University of Florida. For some time various State and Federal organizations have been try-ing to obtain data on the relative movement or encroachment of chloride toward the interior. Because there has been a great deal of land loth, to agriculture through the encroachment of chloride the Soil Conservation Service in cooperation with the Sub-Tropical Experiment Station set up a study in August, 1945 to study the movement of chlorides in the marl lands of South Florida. The geological survey again had funds toroarry on their operations in connection with chloride intrusion. The three organizations combined their efforts in trying to get data on the rate of encroachment of chlorides. The Geological survey to s tudy the underground and anal movement, the Soil Conservation Service, surface movement and the Sub-Tropical Experiment Station; the tolerance of various tyrpe of crops to chlo ride . In February, 1944 when the truck farmers in the Northwest section of M~iamni along the Tamiami began having trouble with chlorides, we set up a sampling area covering this section to~ be sampled periodically with thwo purposes: (1) to try to obtain some data on orop toleranoeas (2) to see wvhat the time effect putting a salt barrier ia the canal would be in improving salt conditions. Table #711 gives the location and p.p. million of chlorides in this area franm lardb 26 to June 10, 1946. It will be noted since the initial sampling in M~arch that there has been a constant lowering of the concentration of chlorides in the surface layer t~hroutghout this area. This is due, to the leaching effect of the summer rains. This same thing was noted following the hurricane in Sep- ~teniber, 1945. The resulting higa tides raised the concentration of chlorides in the marl lands East of Allapattah road to around 10,000 p.p.m. of chlorides and for a time it looked like very li-ttle of the land could be used for agriculture but following: this the rainfall was quite heavy and it was found that because of the high water table and leaching action of the rains a greater portion of the area was usable. Table #2 shows tolerance data we have been able to collect since the initiation of the project by Dr. WIestgate of the Sub- Tropical Experiment Station and myself, It will .be noted that various types of orops seem to have a greater tolerance to salt than others. It must be understood that this data is only presented as an indication and future work may change it somewhat, Our data at present would indicate that beans are the least tolerant,- followed probably by such orops in approximate order of tolerance as, gla~dfltts, onions, straw- berries, lettuce, corn, tomatoes, potatoes, broccoli, cauliflow~er and beets. As I stated before our data at present ~indicates that crop tolerances will about follow in this order but to date we do not have sufficient data to define the exact crop tolerances or to compute the exact reduction in yield as a function of saline intensity. However, there is abundant evidence that salt has in same cases destroyed crops in Dade County and in many cases materially reduced -the yields in both peat and rrar1 lands. Too from data accumulated to date from leaching effects it would appear that much of the land now hampered for agricultural production by salt could be brought back into production at a relatively early date provided future saline intrusion is prevented. WATER TABLEF STUDIES Effect of Eigh Water Tables in the Everglades Upon thze Wfater Table in the Rockdale (Limestone Complex and Malrl Soil of South Florida) Data to, date collected since the initiation of the water table studies indicate that as soon as there is no addition to~ the water table in the back country the water tables for the area between the Everglades and the coast drop rapidly. Toward the end of the winter season, the water table in this back country was about three and a half to four feet below ground surface. (Ground elevation approximately 7.0 feet). While at Eighland plots south of Florida City with a ground elevation of about 4 feet, we had a ground water table a little over four feet below ground surface .19 feet. Thia law occurred at the end of April. In Miay there was recorded about 18 inches of raia at the corner of Mowray Street and Redland Road. Raiins in the back country were much less as shown by our studies. During the period we had a rise in the water table in coastal a rea of fran 4 to 5 feet. IImmediately following this we had a period in which very little rain fell in this area. During this period the well in the corner o f Mawrry Street and Redland Road which is read daily dropped about 0.2 of a foot per day. This excessive drop wa~s due to tont factors: (1) there is a free out flow of mater through canals in the coastal area; (2) the water table in the back country had not built up, so there was very little recharge from this area. -2- Data at present indicates that when the water table in the Everglaides drops to 2 64 feet belowP ground surface the water tables throughout this section drop excessively. As a result 'of this to maintain good growing conditions, the grove owners must irrigate more. frequently. If the water table in the back country could be maintained at a higher level and dsua be placed in the coastal canals, wre should be' able to hold -a higher water table in this area. Pre- requisites are -- salt barriers and water control structures to retard flow during low water ia all of the presently uncontrolled canals in this area. Mdelvin E. Gallatin -3- W'. A. Glass Direcltor COPY DEPACRTMENTT OF WATER ANZ~D SEWERS CITY OF MIAMLI P. O. Box 4832 Miami 31s Florida July 10, 1946 War Department Engineering Office Jacksonville, Florida Gentlemen: We are handing you herewith original and three copies of a Brief in support of the Dade County Engineer Department plan for water control on the Miami Canal, as presented at the Dade County Courthouse, Miami, Florida, on July 11, 1946. There is also enclosed original and three copies of the statement of Milalcolm Pirnie, Consulting Engineer for the De- partment of Water and Sewers of the City of Miami, as submi-tted at the same hearing. Yours truly, (Signed) BS A. Glass 1NAG/g Enolosurea COPY A BRIEF IN SUPPORT OF TBE DADE COUNT~TY ENGINEER DEPARTMENT PLAN FOR WABTER CONTROL ON THE MZAIAI CANJAL By WT. A. GLASS, DIRECTOR DEPAR~iiENT OF WATER ANJD SEWAERS OF THE CITY OF 6IAMI Presented for the WA'1IER AND SEWER BOARD OF TBE CITY OF M6IAMI Miiami. Florida One of the most serious problems that the citiseena of M~iamni and Dade County have to solve is that of salt water eneroslmanat.. It has. already cost the local taxpayers hundreds -of thousands of dollars in actual cash due to loss of producing wells, many of which can never be reclaimed. additional wells are at the present time threatened a potential loss; and the wholw salt water encroachment problem is caused by and due to the uncontrolled drainage. Uncontrolled drainage has wrought serious damage to property owners and taxpayers who oma lands on the Coastal. Ridge. Drainage was not planned to affect any laind but that in the Evergladee; the idea was to remove the water that flodded the organic soils behind the Coastal Ridge and thus open up to agricultural pursuits a vast, rich, sub-tropical swamp. But the canals that were dredged out through the swamps also cut through the Coastal Ridge, and these same canals that wsere to draia the E erglades nd; only did that, but, they also drained the Coastal Ridge. The drainage canals were bet designed as water control canals they were to carry away the water from the swamp lands. And, to a certain extent, they have been quite successful in achieving this end. The drainage canals in this County have run open and uncontrolled all the years since they were dredged, wet years and dry, until, at the insistence of the City of Mliami, and at its own expense, a salt water barrier was temporarily installed in the M~iami Canal near the NW~R 36th Street Bridge to 1939. The canals have never been ade- gastte to carry off flash floods, so that ~Everglad~es lands are still inundated at times of extremely heavy rainfall. But during t~hnes of low or inadequate rainfall the canals continue to~ siphon off untold billions of gallons of fresh water, w8iasting tehis precious natural resource to the sea. This mi- controlled drainage has not only waorkied to the disadvantage of dwellers.on the Coastal Ridge boy over-draining the ground water of the Ridge, but by drying out the organic soils of tehe Everglades and~ making ::themn~ .inder-dry during the dry season of ;the year, has allowed the ruinous 'glades fires tp spring up, fPouling- the air over the~ Ridge for weeks at a tim~e. These gladea fires are directly a result of uncontrolled drainage. They are not oaly a nuisance to the readdents of this area but a distinct cause of loan of tourist trade. Also, by lowering the water surface in the Evejrglades, our winters have been. made more severe the danger of froat to truck farming orops and to citrus crops has been increased many fold. Because of these facts the City of M~iamS Board of Wfater and Sew~ers takes the position that uncontrolled drainage in Dade County must go, and supports the County of Dade in its plans for water control. The several factor -risted above are eada of significant importance, but most vital of all ~is the factor of salt water enorea~chmdent. WOe believe that had there been no d rainage program put into effect, there would be today no problem of salt water eneroachmenti, and in this we have the endorsement of the United States Geological Survey whose scien- tiata- and engineers have been studying the water resources of Southeastern Florida since the Fall of 1939. Salt water encroachment has already ruined two former producing well fields of the City of Mliami. The first well field. to be lost was the Spring Gardens field, located near NWU 10t~h avenue and 11th Streets now a part of the Miami Country Club. TShis well field was used until 1925 but salt water first began to be noticed there in 1918. (Mbajor Everglades drainage canals were begun about 1910 and finished about 1918). Wbhen the Spring Gardens field was first developed, wells were finished at depths of 60 to 90 feet and water from these wells flowed above' the land surface due to the hydrostatic pressure of ground watElfer impoun~ded in the rooks up-gradient fran the well field. Gradually, as the results of drainage became felt, the wells ceased flowing and the formerly fresh water became brackish. To overcome thle brackishness, the deeper wells were plugged up to about 40 or 45 feet, for the heavy salt water was moving in at depth iri the water-bearing formation and fresh water could still be obtained at shallow depths. H Iowiever, even this shallow water finally became salted too badly, and it was necessary to abandon the field. A new site, Ty5 miles inland from Biscayne Bay, on the eastern margin of the Everglades was chosen. That site is the location of' the presented well field. Part of it lies in Miamni Springs and part in Eialesh. Badk ~in 1925 it wras thought that moving the field so far out into the back-country was an ultra-conservative move, but the facts of the situation were not then known. Then in 1959, certain wells in this newr field became salted, sane at them yielding water containing more than 1000 ppm of chloride. At about the same time the Coconut G~rove well field which is located about a mile from Biscayne Bay and about 5/8 adle easterly from the Coral Gables Deep WCaterway begma to show salt nater contamination. Our public water supply t~huzs threatened, a request fran the Cities of aiiami, Mlianii Beach, Coral Gables, and fran Dade County inas sent the United States Geological Survey to investigate our water resources~. WIe wanted to know all the facts about our present and past .supplies; the factors controll~iag this salt water invasion; whether it could be stopped or not; where other supplies might best be obtained in case the local supplies weFre doomed; in other words, a coamlete investigation. In the meantime, in spite of all the efforts our water department eng~inners empqloyed, no seYthod was found to enable us to continue the use indefinitely of theciGoconut Grove field. In desperation an attempt was made to obtain water there by digging a huge rectangular pit (essentially a.1arge open well) the bottom of which was ;just about at sea level and slightly below the water table. However even this very shallow ground water became highly contamrinated wlith sea water and had to be abandoned, The Cooonuat Grove wiell field 'was dead, the money invested in it entirely gone. Thus, in the short span of 16 years (1925 to 1941) Greater MBiams had lost two well fields to salt water encoreachment -aLatiff; price ~for city folks to pay for a drainage program that was 'intended to make lanid usable in the Everglades. Of course, this was not the only loss involved to city taxr- payers for there is a considerable body of cityllandt.that ~ies within- the boundaries of the Everglades Drainage District, and drainage taxes of land holders on these city lands helped to pay for the drainage program. Not to be overlooked, but difficult to evaluate in cash, is the loss to citizens of Greater Miami caused by the ruination of their private well supplies by salt w~ater. Hundreds, perhaps thousands, of private wells have been rendered useless in a coastal strip averaging about 1~ miles wide in Dad~e County; and in tongues extending inlaned along each of the tidal drainage -canals well supplies have been ruined as far inland as 5- mniles from Biscayne Bay. (as along the Miami Canal to a point west of LeJeune Road). The United States Geological Survey has shown in their several publications that our ground later supplies are being attacked by sale water eneroackmnet in two different but related ways: (1) Up tidal drainage canals, at times many miles from the Bay, and then leaking out through the aides and bottans of the canals to contaminate fresh ground water along the canals. It was this type of enoroacknent that ocataminated the Mbiami Springedfialesh field in 1939 and that has since givena trouble on several occasions when, due to a accident or inability to install a control dam in the Mliami Canal in time, salt water occupied the-atre~tch of the Miami Canal adjacent to the present; well field. (2) By moving in from the Bay all along the shore line and displacing fresh water in our huge underground reservoir. It was this kind of enoreachlnent that ruined the Spring Gardena J fields possibly aided by No. 1, and a combination of Nos. 1 and 2 that ruined the Coconut Grove field. The United States Geological Survey geologists have measured our aquifer. Thaey find it to be a wedge-shaped mass of highly permeable rooks with the thin, edge of the wedge to the west. The highly permeable aquifer is about 125 feet thick at the western shore of Biscayne Bay, about 100(' reet thick at NW~r 20th Street and also in the vicinity of the well field, and somewhat less than 40 feet at the Dade-Browsard Levee. Quality of the water in the aquifer is best under the coastal Ridge, with the best water of all to the south in the Peters-Homestead area.' Under this wedge of highly permeable rooks is a thick section of clays, $ilta, and very: fine sands in which there is essentially no movement of water at all. -5- To control the movement .of salt water in the Mliami area there are two> things that must be done: (1) By the placement of bParriers in the lower ends of tidal ommals to prevent the free passage of sea-wna-ter up these canals whfen conditions are favorable for it to do so. (2) Raise ground water levels high enough to build in effect a fredb water dam. Such a fresh water dan would of necessity have to be under the Coastal Ridge, and as close to the shore of Biscayne Bay as possible. The depth of 100 feet to the. relatively impermeable lays, ailts and sands that underly our highly permeable aquifer demand 2)i feet of fresh water above meIs.1. Such a height of fresh water would have wieight enough to depress the encroaching sea water to the very bottom of the aquifer, and fresh water would thus fill theequifer fran top to bottom, and prevent further inland movement of the salt water. The placing and proper operation of control works in the several tidal drainage canals of this area would accomplish.itchs objective. It would save the nowr~-threatened city well field indefinitely and would eventually re-freshen and once more make usable wells in the area to the west of the controls. It would also reclaia some of the aquifer downstream from the controls, through freshening of the shallower portions of the aquifer. It has already been stated by the United States Geological Survey in one of their reports (Parker, G.G., Ferguson, G.E., and Love, S.K., Interim Report on the Investigations of W~ater Resources in Southeastern Florida with special reference t the MDiami Area in Date County, Fla., Geol, Suxry. Rep't. of Inv.~ Noc 4, 1944, p. 33) that -6- "The farther downstream control structures could be placed and operated ia these (Mlini, Tamieumi, Little River, Biscayne, Snakre, and Snapper Creek Canals) and connecting canals which discharge into salt water, the more effective salt water control wBould became, and the closer to the Bay encroaching salt water would be held". It seems needless to point out that although the p esent temporary dam in the Miari Canal, near NWS 56th Street Bridge has temporarily saved the werll field, it is too close to the cone of depression surrounding the well field to be retained as the site, of the permanent 'structure. Monthly unpa of the weall field area showing water table conxtours and isoohlors have been issued by the United Stat~tes Geological Survey since 1939; the-se monthly maps indicate that even with the dam to place salt water is still moving island at depth in the aquifer. This move~ment is very alow, and because the United States Geological Survey scientists haven't ha~d time to observe the movement long enough to determine its rate of movement inland, the rate isn't e exactly known. To determine this, observations would have to be carried out over a period of years several times as long as the United States Geological Survey has had already. The Dade County Engineer Department has proposed a control works iB the Miami Canal at; NW 20ta Street. This is 6 miles downstream franm the well field, whereas the present site of the temporary dam at NW `36th Street is only 2-3/8 miles downstream. The proposed 20th Street dan and looks site would give the well field an additional s afety factor of 1-5i/8 miles aP fresh water on the s'eward side of the well field, and would give immeasurable relief fran salt water enornacknhent. -7- This 20th Street site has not only the advantage of removing the salt water front downstream in the Mifanij Canal, but it would prevent salt water fron finding access to the Tamisni Canal and thus fran attacking the well field on its southern and southeastern flanks. 20th Street is down- stream fran the confluence of the Miani and Tarmiami. Canals. The 20th Street site would also prevent salt water fran entering into mald becoming trapped in the deep rook pits kcnown3 as Seminole and Palner L kqa. These pitas or lakes, are excavated to average depths of about 20 feet, but have lobal deep spots of about 40 feet. Thus, their bottoms are deeper than the inlets fron the canals and once salt wamter finds its way in it does not flow back out again The salt water is heavier and denser than fresh water so sinkrs bottomwvard and seeps out through sidles and bottoms of the lakes to contaminate ground water on all aides. These lakes thus become local "arms of the sea" and~ are focal points of ground water contamination doing untold damage to the fresh water. Because of all these facts ~recited above, it is the sincere desire of the City of Miiami Boiard of 1Water asd Sewers that a control works be placed in the NBiand Canal at NWQI 20th Street as planned by the Dade County Enginieer Department. This Mbiami Canal Control is a key point in the overall program planned by the County to combat over-drainage; it would save 'the present well field indefinitely; and it would reclaim a large part of the aquifer now contaminated by salt water. Of course, it may never reolain all of the aquifer already con~taminated along the shoreline of Biscayne Bay, nor would it restore ground water levels to their former h65ghts, either in the E~vergladles -81 or under the Coastal Ridge; neither would it of itself prevent entirely the burning of dried out organic soils in the Everglades. However, it would prevent further salt water encrera~chment and would reclaim some parts of the aquifer now lost. It is the best answer to the salt water encrgsachment problem that is possible, considering the many factors bearing upon it. .g. July 9, 1946 STATEMENT OF 2SeeinmRE T. K~NAPPEN Consulting Engineer for Dade County Water Control Progran at Hearing on Miani Canal Lock held by the U. S. Engineers July 11, 1946 Mr. Rath~ has already given you a general outline of the problem involved in checking salt water intrusion along the Miami Canal, and the steps which Dadie County proposes to take in order to carry this program out effectively. We have been working wNith and advising Dade County with respect to the measures that should be taken and the type of structure that should be built. First of all, there is the general question as to whether any control needs to be instituted along the M~iami Canal. Th~e best answer to this is that a considerable volume and area in the ground water reservoir normally occupied by fresh water in the vicinity of the 'uiami Canal and the Tamiami Canal has to some degree been salted up. Clearly, this has been due to the very large channel which has been provided in the M8iani Canal, The effect of this canal is to provide a salt water front on either bank of the canal very similar to the salt water front on Biscayne Bay during the dry season of the year, that is, for a period of some seven or eight months. During this time, the concentrations of salt in the MJiami Canal are very large, approaching sea water. The effect of this Is to provide a zone on either side of the canal where a salt water front meets the fresh water and th~e canal serves to drain off the fresh w~ater. Nuow writh the Miiami Canal coming close to the well fields and the draft on the well fields during the dry season reducing the volume in the fresh wc~ater reservoir, salt water wats drawn in to the well fields, first, of course, in very small concentrations. This led to the construct-ion of a pneumatic dam above the government channel at 36th Street, the purpose of which wras to hold the water above the dam at a higher elevation than the water below the dan. This structure failed and wras replaced temporarily by a steel sheet pile dam which has been effective in checking the salting up of the w-ell fields. In viewr of the experience already gained with the structure at 36th Street, first consideration w-as given to the construction of a look structure at 36th Street and a similar one on the Tamiarmi Canal above its junction ji~th the Miami Canal. The idea would be to hold the water level at these structures about 2y- feet above mean sea level.Thsoudb sufficient to more than balance the difference in density between fresh mad salt water and maintain this differential except at times of extremely low flow, when the draft on the well fields might prove to be great enough to lower the water table over a very considerable area. In any case, since during this period: there is little replenishment of the ground water table, the draft on the well fields creates a cone of depression. Of course whlen this exiists and when the salt water face is close to the depression cone, there is a strong tendencyr to pull in damaging amounts of salt water i~nto the well field. In our opinion, the location of the look at 36th Street is so close to the w;ell field as to make the w~ell field unsafe, and therefore if protection is to be provided for this wIell field the salt w-ater barrier must be moved further dOwn~streaml It wiill be desirable to move this look structure out as close to Biscayne Bay as possible. However, it would seen to me a serious problem to put the look in the mouth of the Mliami River for manyr reasons. The most practicable si~te for the look wans found to be at the site now7 proposed, which is some thousand feet below the junction of the Tamiami and Miiami Canals. In our opinion, this location is sufficiently far down to protect the w~ell fields an~d to re-establish a considerable area of fresh water storage between the structure and the well fields over a period of time. We therefore feel justified in recommending to Dade County that a barrier structure be placed at this location. In our opinion, a structure at this location will be far enough dowvn to protect the wrell fields and also will ~be effective in re-establishing a considerable amount of fresh water storage. Wie further believe that at this location the wrell fields will be safe, against salt wrrater intrusion, for an indefinite period in the future. A series of studies have bteen conducted by Mr. S-tephens, 'iater Control Engineer for Dad3e Cou~nty, to develop economic justification for the proposed work. These studies, which wfill be presented to you by him, show that the proposed installation will provide benefits greatly in excess of the cost of the project. The location selected for the salt water barrier lies within the limits of the U. S. Government navigation chan- nel. Dade County, therefore, is asking for a permit to place this structure in the navigable channel. In order to provide the least possible hardship to navigation, it is proposed to construct twlo looks in connection with the barrier. Each one of the looks would be controlled by a gate upstream and dow~nstream with a look chamber between the gates. The larger one of the locks would have a depth of 15 feet below mean sea level, which depth is below the bottom of the navigation channel wrJhich is set at 15 feet below high water. The width of the large look structure would be 40 feet and the length of the chamber between gate monoliths would be 320 feet. A study of the navigation moving in the canal has been made, and it was found that the w~idthz of this look is great enough to permit the passage of any vessel or barge which navigates these waters. It is also long enough to take the longest towrs which were brought through these waters without breaking them up. About 70 percent of the boats passing this point are small boats, less than 60 feet in length and 18 feet in width, and generally having drafts of 5 or 6 feet or less. To provide for these vessels, an auxiliary lock chamber 18 feet by 60 feet writh 7i feet of depth below~ mean sea level is provided. Ti look wrill take all the anall boat traffics at ordinary times. On holidays, wh~en the small boat traffic is very heavy, it wJill be necessary occasionally to use the large look to take these boats through. It is not intended at this time to submit the details of the proposed look construction for approval. General plans only have been submitted.' Howtever, it is proposed that the look design will be such as to permit the movement of vessels and barges through the structure w~i~th the least possible delayS. It is planned that the gates will operate from fully opened to fully closed position in twso minutes for the large look and one and one-half minutes for the small look. It is proposed that the water will be equalized in thie look chambers in less than twio minutes. W~ith this procedure, there should be very little loss of time and therefore very little delay to traffic. The delays have been e estimated by Micr. Stephens in his report and are believed to be quite conservative. A navigation traffic count wFas unde for the Months of November 1945 through Masy 1946 inclusive at the location of the proposed structure at N.W. 20th Street. A similar count was made at the Tamiami Canal in N;WJ. South River Drive for the Months of January, February and MIarch 1946. The results of these traffic studies are summarized in the following tables: /i ,L t ,ib~.~ ~a It wvill be seen from the foregoing that the average monthly number of lockages for the mlain look for commercial vessels would be 222 per month and for pleasure craft over 60 feet in length 86 per monta, a total of 308 per month. These would largely move on wreek-days, so that the average nudmber per day would be approximately tw~elve. The maximum per day is approximately double this, or twrenty-four. Fre- quently more than one vessel or tw~o would pass through the look at a time. Based on an average thme of 20 minutes per lockage, the maximum demand could be handled in less than eight hours, or one-third of the time. It would therefore appear that the proposed mrain look: was of amp~le capacity to take care of present and future traffic. The average number df lockages per month for pleasure craft under 60 feet in length is 652 and the maxinum 924. This is so average number of 20 to 30 per day. This nudb~er can be easily handled by the small look, particularly when it is considered that several of these boats may pass throughthe look at one time and also that they may pass through the large look along with commercial vessels. On Saturdays, Sundays and holidays, the maximum nudmber of pleasure craft may be 100 or more. On these days the commercial business is lights and as many of the pleasure craft as appear in excess of the capacity of the small boat lock can be taken through the large boat look in groups. It may be seen from analyzing the foregoing data that the proposed look structure is adequate in size and capacity to take care of the present traffic and any reasonable expectation of future traffic. It is proposed to design the gates so that they may be removed for maintenance and repair with a minimumn of delay to traffic. Their design will be such that they can be removed over-night for annual overhaul during the period wrhen flows are high enough in the main stream to make the use of the look unnecessary. The dan structure itself will provide six 10-foot wide flood-gates with protection against back pressure. The type of gate selected is the bottom hinged gate known also as the tumb3le gate. TPhis has particular advantage in the maia look when the look is being used by shallow draft vessels, as it will not be necessary to lower the gate all the way down and thus the salt water flows which follow the bottom of the daannel can be impeded. In times of flood flow8a, all the dan gates as well as the look gates, may be opened wide and it will then be possible to pass the greatest possible flood that can come down this channel at a comparatively low velocity. WYith a flow of 4,000 e.f.s., the velocity will be less than 3 feet per second. This flow is greater than the greatest experienced flows. The location of this look at the site proposed will have a number of beneficial effects upon navigation. In the first place, the effect of this barrier will be to stop the movement of the tidal prian at that point. This means that the tidal velocities below the barrier will be considerably less, since the large enount of tidal flow required to fill the basin above this site will then become unnecessary. The result will be that th~e tidal velocities just below the look will be negligible, and will bej considerably reduced from there to the mouth of the M8iami Canal. Above the dan, the tidal fluctuation will be eliminated and there therefore will be no tidal velocity. The only currents will be those of the drainage and flood waters. above the look there will be fresh water 12 months in the year. This will make locations above the look most desirable for anchorage. It will also permit the opening up of Palmer Lake as a fresh water anchorage and mooring basin. The effect of the looks also will be to provide a uniform stage in the canal upstream from the looks. This will be advantageous for mooring a~nd docking of vessels. It is believed that the benefits to' navigation will very largely offset the cost of the delays involved. The other benefits which will acorne from this projects that is those that come fran maintaining the freshwauter underground reservoir, are very great and far exceed the cost of the proposed project. It might be pointed out at this time that the alternate sites considered for the water control structures are above~he navigable channel. Lock:structures therefore would not have to be as large as at the proposed location, or if they were built as large, the cost of the installations would be very great and there would be tw~o lookstructures to be maintained and operated perpetually. Now it is entirely possible that the development of Mdiami will make it advisable to extend the navigation channels further inland and there is no reason why this should not be done with adequate salt water barriers. The proposed location of the look below the Sunotion of the two streams would be the most advantageous location once this future development is sooomplished, for navigation could come out of the Tamiami Canal and go up the Miami Canal without having to pass through any looks, as against having to pass through two looks if the upper locations were selected. You wrill hear fron a nanber of others at this Hearing, who have been studying the problem of salt water intrusion for many years. It is the consensus of opinion of these experts that the look and dan structure for the purpose of stopping salt water intrusion and maintaining fresh water levels should be placed below the junction of the Miami and TamingS Canals, and that the site selected and recommended at this hearing is the farthest upstream that this structure should be located to meet the situation effectively. It is also the opinion of these experts that it is vital to this community that this structure be installed. To sum up: 1. The proposed structure is necessary for the maintenance of the fresh water reservoir upon which Mia~mi depends for its water supply. 2. T~e structure cannot be located further upstream and be fully effective. 3. The structure will not prove to be an unreasonable obstacle to navigation, but will in fact provide considerable benefits to navigation. 4. It is therefore believed that the permit requested by Dade County for the construction of this structure should be granted, subject of course to final approval of detailed plans by the 1War Departmpent. EINAPPEN 'ENIINE~ERING COMPANY By (Sipled) _Theo~o~re T. Knappen MaAULE INDUSTRIES Ojus, Florida July 2, 1946 Col. AL. B. Jones Re: Proposed Look: in Miami River at District Engineer N.W. 27th Ave., MEiamri, Fla. U. S. Engineer Office Jacksonville, Fla. Sir: As a firm wrho is just completing a large investment on Tamiand Canal west of Red Road (NS.W.i 57th Ave.) we w~ish to have our com- ment twith reference to the proposed look in the Mdiami River at N.W. 27th Ave. considered and entered in the record. W~e are comple-ting a ;c500,000.00 stone crushing plant, quarry, and concrete block plant on the property lying between Tanismi Canal on the south, Miami Air Depot on the north, FEC and SAL Railways on the wesst, and Red Road on the east. WNe will trans- port our products by barges dowvn Tamiarni Canal to M~iami River, through the proposed look and thence to delivery points. W1e are as vitally affected by the proposed look as anyr operation could be. After a detailed discussion with MLr. Earle M.i Rader, Dade County Engineer, as to the size of the look, depth of water, mechanical operating time, etc., we are convinced that the look will be a slight convenience at most. Wie are further convinced that this slight inconvenience cannot be compared to the tremendous good the people$ of Dade County will receive from the proper control of their wa rer supply. In conclusion, please understand that our firm is in favor of the proposed look. Yours respectfully MLAULE INIDUSTRIES (Signed)R. G. Willianas Partner 0 & FR So~lA or I MIblIRON ANJD PdETAL COMPANY Office and Yards 2481 N.W. 32nd Ave. Mdiamni, Florida SALKGBB-3 800.61 (6618) Miami Earbor Biscayne Bay, Florida June 25, 1946 Wlar Department United States Engineers Office Jacksonville, Florida Attention: A. B. Jones, Colonel District Eng;ineer Dear Sir: This i~s in regard to the construction of a look and water control dam in the Miami. River as outlined in your notice of June 11, 1946. Our principal business is salvage. W~e wwn a number of lots on the Mliami River above the proposed site and wiish to state that we approve of the project providing that the lock will not interfere with river traffic. It is our understanding thab the locks will be 40' wide, 320' long; and 15' deep in which case that should not interfere with barging operations but -a are not familiar enough with looks to understand whether or not they would interfere with sameu. Our opinion is that there are msupr benefits to be derived fran water control which w~ill enhance the v-alue of our property~ on the river front as well as be a benefit to agricultural anid other community interests. Certainly we would not want to imperil the water conditions of Greater Miiamd. HYe handle a considerable amount of barge material in barges that carry faom 150 to 400 tons and anyrthing that wie can do to help the city out, we will be glad to do, of course, without jeopardizing our business. The WJar Department of the United States Engineers Of~fice of Wlater Fronts certainly would kmow whether or not this would obstruct freight traffic on the Meiami River an-d if it did not, there would be no objection on our part. Yours veryT trulyr MIIAM~I IRON &c METALS (signed) Meyrer Schwrartz gygyY Meyer Schw~a tz BELCKER OIL COMPANY M~iami, Florida July 9, 1946 Col. A. B. Jones District Engineer United States Engineers Jacksonville, Florida Dear Sir: It is our understanding that the County is contemplating construe- tion of a dam in the Misni River, the hearing for the issuance of a permit for this purpose to be held June 11, 1946, It is our desire to go on record favoring this construction, as in our opinion the protection of water supply of the city will be vitally affected as far as salt water intrusion is concerned unless some steps are taken, such as the construction of this dan to pre- vent this salt water intrusion. l'his company owns some river frontage above, or west, of the loca- tion of the contemplated salt water intrusion dom and while some inconvenience may be caused by this contemplated construction it is our considered opinion that the protection of this city's -a~ter supply is more important than any personal inconvenience that may be suffered by those whose property is located west of this contem- plated construction. In view of the above circumstances, wre recommend that the permit applied for by the County for this construction be granted. Yours very truly, (Signed) C. B. Chinn C. B. CHINN President GBC:M: G 4 Lr r * r lC COPY UNITED STA~lTES DEPARTMENT OF TUS INTERIOR GEOLOGICAL SURVEY P.O. Box 2529 M1iami 15, Fla. July 5, 1946 The District Engineer, United States Engineer Department, Jacksonville, Fla. Dear Sir: The attached "Summary of conclusions reached after six years of investi- gations of the geology and ground water of the Greater M~iarni Area, Florida" has been prepared by the writer in response to a request from the Dade County Engineer Department. The summary is intended to be used in connection with a public hearing to be held in Mriami by the United States Engineer Department on July 11, 1946, when the subject of a control structure in the Mdiami. Canal will be discussed. The United States Geological Survey does not enter into this hearing as a partisan. The data we have to submit is offered without prejudice or bias, and is factual. It is based on somewhat more than six years of intensive investigations of the geological and hydrological conditions controlling the occurrence of ground water in this area. The United States Geological Survey has made these investigations in financial cooperation with the Cities of Miami, Miiand Beach, Coral Gables, the County of Dade, and the Florida Geological Survey, the investigations being part of a nation-wide program the aim of which is to learn the facts of our Nation's ground water supplies. Very t ruly yrours, (Signed) Garald G. Parker Garald G. Parker Geologist in Charge Ground W~ater Investigations in Southern Florida 00PY SURRE~RY OF CONCLUSIONS REACKJED ACFTER SUIX YEARS OF INVESTIGATIONS OF TBE GEOLOGY AND GROUND WAE~alR OF THE GREATER MIAMI -AREA, FLORIDA by Garald G. Parker, U. S. Geological Survey It is not believed necessagy at this time to delve into the history .of the water resources problems of the Greater Miani Area, nor to describe in detail the work done by the U. S. Geological Survey in cooperation wnith the Cities of Miami, Mdiani Beach, Coral Gabless the County of Dade, and the Florida Geological Survey in studying these problems. The data have already been presented in almost twenty separate reports. Of these, perhaps the ones that bear most on the problem of water control are the following: (1) Parker, G. G., Fergusan, G.E., and Love, S.K.: Interim report; on the water resources of southeastern Florida with special reference to the Miami Area in Dade County, Rep't of Investigations No. 4, Florida Geological Survey, 1944. (2) Brownm R. H., and Parker, G.G. : Salt water en~crueachment in lImeL stone at Silver Bluff, Niami, Florida, Economic Geologys Vol. LL, No. 4, 1945s PP* 235-262. (3) Parker, G. G.: Salt water encroachment in southern Floridas American Water Works Association Journal, YTo. 37, No. 6, 1945, pp. .526-542. (4) Gross, W. P., Love, S.K., Parker, G. G., and Wallace; D.S., Progress report on the water resources investigations in southeastern Florida, mimeographed, in two volumes. Text in Yol. 1, illustrations in Yol. 2, 1940. (5) Parkers *. *, Late cenozoio geology of southern Florida with a discussion of the ground water, Florida Geological Survey Btill. :1. ; ',Nb.187, 1944. Copies of Nos. 1, 2, 3 and 5 listed above are attached herewith for ref- erence. No. 4 is out of print, though a copy is available at the Miami, 00818 and Whashing~ton, D.C. offices of the U. S. Geological Survey, and each cooperating official has one copy. Although there are many conclusions that have been reached as a result of the geological and hydrological studies m~ade by the U. 3. Geological Survey in this area, the minor ones need not be recited here. Only those of major import will be considered. (1) Prior to drainage development in southern Florida there was no problem of salt water encraochment. (2) Prior to 1942 (between the beginning of the encroachment and Feb. 4,-:1942) salt water had been moving inland at depth in the fresh water aquifer at a rate of approximately 235 feet per year. (3) Between Feb. 4, 1942 and Oct. 28, 1944 salt water moved inlead at; depth in the aquifer at ma average rate of approximately 890 feet per year. (4) The 890 feet per year rate occurred during the drouth of 1943-44 and is probably not the yearly rate at which salt water will continue to encreach There are definite indications that under conditions of heavy rainfall and high water tables the salt en- oroachment is not only slowed down but; in places moves seaward, The overall trend, however, is for the salt water to move inland. (5) Salt water moving at depth in the aquifer is behaving according to laws of physics, and responds to increases or ~decreases in the weight of fresh water above mean sea level by moving seaward or land- wcard. When water lev41s fall salt moves inland; when they rise high enough it stops or even moves seaward. (6) Drainage has so lowered the ~weight of fresh water above mean sea level in the MIiami area that the long established equilibrian between salt arnd fresh water has been upset, and under the laws of physics the salt water is gradually moving inland seeking a balance under the new conditions. (7) Geological conditions are such that the aquifer in the M~iami area is very highly permeable. Furthermore, the aquifer is underlain by about 400 to 600 feet of relatively impermeable~ materials whPich prevent the easy movement of water through th~em. These geological conditions permit the natural development of a great underground storage reservoir sea'l8a off fran waters below, ~but open to water above and on tile sides. The aquifer is wedge-shaped, thick toward the shore and thin toward the interior of the Florida peninsula. Along Biscayne Bay it will average some srat more than one hundred and twienty-five feet in thick- neas; in western MTiami it is about one hundred. feet; thiolk; forty miles west it is only about ten feet thick, To the south it becomes shallow-; er, being only about sixty feet thick in the H~omestead-Florida City area, but it is very highly permteable. To the north of M~iami the aquifer extends somewhat beyond Delray Beach, but becomes sandier and sandier to the north. In the Everglades' and to the north of Delray under the Atlantic Coastal Ridge the aquifer interfingers with or grades into the Caloosahatchee marl, a material of relatively low permeability. Very little ground water makes its wayp out of the Caloosahatchee mar1 into the principal aquifer of this area. (8) The amount of wat1er taken from the present well field (from thirty to forty million gallons a day) is only a very small amount of water as compared to the large amount available. -2- ( The effort of the well field does not ever extend over a very great distance -- the radius of the cone of depression is seldom Over a mile. (0 Because of the geological controls, the water supply of the Greater Maiand area, which is taken from the huge underground reservoir above described, is almost- entirely derived from local rainfalls Very' little water is carried into thes aquifer fran areas outside the boundaries of the a~quifer. (11) Bgogause of the controls over salt water encroachment exerted by the f"~`i lawHs of physiCS and geology, it has been determined that salt water in the Mdiami area will come eventually to rest in equilibrium with iL' fresh water at the place where the he~ and one-half foot average annual contour on the water table exists. The salt water is denser and has a greater weight than freshwater, s~o much so that a forty foot column of salt water weighs the same as a fortyT-one fb ot column hf fresh-water. This;gives rise to the Bhyben-:Rerzberg Prinoiple used by geologists and engineers in de- termining the depth to salt water in a coastal zone of permeable materials where salt ansd fresh water come into contact. Simply, the Principle means that for each foot of fresh water that exists above mean sea level at the zone of contact there will be an additional forty feet of fresh water below. (12) Since the aquifer here is one hundred feet thick, and it is desired to have it completely filled with fresh water fran top to bottom thus leaving no room for salt water at all, it is necessary to have tos and one-half feet of fresh water above mean sea level (2i x 40 = 100) to accomplish this. (13) The maintenance of ground water levels at an average yearly stage of two and one-half feet above mean sea level1 can only be effected by 'controlling the canals which draia Dade County, and the greatest de- Sgree of control that can be effected probably will not prevent some ~.' further inland movement of the salt water in the aquifer; however, it would preserve a substantially large area that otherwise would be lost to encoraching salt water, and it would reclaim some parts of the aquifer now salted, especially those parts extending inland several miles along the tidal canals from the main body of salt water con~tsmina- tion. (14) The farther downstream control structures could be placed and operated in tidal drainage canals in Dade County, the more effootive water o'ont~rol would become, and the closer to the Bay the encroaching salt water would. be held. -3- (15) The temporary dams that have been in operation in the Miamni Canal at N.W. 36th St. are all that hars saved the present well field of the City of MtiamIi and all the private wells that exist; in the E~ iale~a-M~iami Springs area to the west of the dam along; the Canal, E however, these dams have not been wholly effective for none of them has actually stopped the westwrard ereep of the salt water at depth iii in the aquifer. This is shown, by a study of the monthly maps of the Miami well field area, prepared by the Mdiami office of the United States Geological Survey. These dams have not stopped~ salt water encrea~chment at depth in the aquifer because they were not designed to raise the water table behind t-hem. Their function was to prevent the movement of salt water in the canal upstream from the dams. The: several dams that have been installed at the 36th St. site have prevented, to a large extent, the salt water from finding free access -to the stretch of the Canal adjacent to the well field, but on occasion when the dam has been out of place or broken salt water has penetrated inland adjacent to the wlell field in the Canal. This has brought about local and small scale saltinrgs of the areas adjacent to the- canal, and at the present time some of that salty ground water is ~prsent adjacent to the well field. ~(16) The development and putting into s ervice. of five new wells in the upper field, and cutting down of pum~page in the old "lower field" has caused the cone. of depression around the well field to change location. It has' moved about one mile north and 0.7 mile farther fran the front of the tongue of salty ground water headed toward the well field and now situated (the front of high chloride, 500 parts per million or more) about 0.7 mile Northwest of N.W. 36th St. Bridge. This temporarily makes the field safer, because salt water now will have a greater dis- tanc~e -to travel th gain access to the wells. However, .for the safety of the well field, this change of position of the cone of depression still leaves the outer edge of the cone too near the tongue of salt waster mentioned above. If the well field is: to be saved it; will be necessary to have the control located much thrther down- stream than 36th St. preferably below the mouth of the Tamiami Canal. If this were done, the area between the well: field cone of depression and the dam would be increased by whatever distance the control were moved. Properly controlled so that only fresh water ever occupied the stretch of canals abovethe control works, the wellj:efield should be safe for years to come. (17) If it should not be deemed essential to save the pr-esent well field ,\ and all the private wells along the Miami Canal, the loss involved would be mainly an economic loss. The aquifer is large enough add pro- ductive enough that numerous well fields of the capacity of the present one could be developed within thirty miles to the south, fifty miles to the north, and fifteen to eighteen miles to the west (of downtovm Miami). (18) It would not be possible to develop large supplies of ground water in the Everglades more than fifteen to eighteen miles west of the coastline. This Is due to the thinning of the aquifer and consequent lesser capacity, to the increasing amounts of sand that reduce th~e permeability, and to the iaoreasing poor quality of the water with distance away from the coast. -4- ICu. &/ '- TP RS 3pyV STATEKENT B1Y COMMhISSIO1BRIORmE: PETERS AT U. S. ENrGINIEER BEARIG ON~ PROPOSED) MIAMI8' RIVER LOCKS July 11, 1946 Miy name is Hugh Peters. I an Vice-Chairman of the Board of County Commissioners of Dade Cotnty, Florida and represent said Board in the absence of the chairman who is out; of the city. The Board of County Commi~ssioners of Dade County, Florida, has been charged by the 1945 Legislature of the State of Florida with the responsibility for the water control program of Dade County. This authorization case as a result of extensive studies made by Federal and State Agencies and widespread local agitation based upon the very real need for ending the intrusion at salt water into many areas in Dade County which have previously been underlaid by fresh water. It was apparent to this community that the intrusion of salt water was causing a 1arge amount of damage and was threatening us with even greater damage in the future. We found that our freshwater supply for the City of :Mami and other communities was threatened, that many of our agricultural lands were being rendered unfit for cultivation by salt deposits, that our fresh water anchorages for small raft were being largely eliminated and that the reduction in fresh water level which went along with this problem was contributing to the rapid destruction of our peat soils. Under the authorization given to Dade County, the County has started a program of water control which has included placing a Irnuber of temporary and permanent dams in various streams, water courses and drainage canals leading into Biscayne Bay. As a result of these measures a considerable firprcvement has already taken place in many areas. This work has been under the direction of County Engineer Earle MI. Rader and his assistant, the County W~ater Control Engineer, John C. Stephens;. The County has also retained the Knappen Engineering Company as consulting engineers on this project, mad Mr. K~nappen anrd MBr. Tippets of this firm have worked with Mdesars. Rader and Stephena in developing a water control program. The most important unit of this program is the proposed looks and dan structure in the Miand River. HPe have already submitted to you a request for a permit to build this structure, and this hearina~s RSI understand it, is called in order that you may receive testimony on this request for a permit. The County Commnissioners would like to emphasize the great importance which they attach to this proposed construction, and ask that you give the matter your early attention, and further ask thatyou grant us the right to build the proposed structure. I shall now ask County Engineer Earle M. Rader to present this matter in more detail to you. /}f)LC~eLNL-Z /RN tS IR9LCOLMB PIRNIE 3iDGINIEERG: New York 18, N. Y. STATENENT OF MALCOLM~ PIMEIE, CON~SULWING ENGINEER FOR, D~EPARTM~IENT OF WATER AND SElilERS, CI TY OF MIAM3I. SUBMITTED TO WAR DEPARTMN UNITED STATES ENGINEER OFFICE JACKSO~NILL;E, FLA. AT PUBLIC HEARING ON APPLICATION OF DADE COUNTY TO CONSTRUCT A WATER CIONT~rOL DAM b~ilTH LOCKS IN~ TB~]E MIAM6I CANWAL APPROX;IMBATLY 275 FEET liPSTRIEA FROM WIESTERLY SIDE OF N, W. ICjTWENTY-SEVEN~TH AVENUE DADE COUNTTY 3TOUNjT HOUSE, MrIAMI, FLA. ~WRSBAY, 11 JUTLY 1946 MA~LC01M PERNIE ENGINaEERS Newi York 18, N. Y. July 6, 1946 War Department United States Engineer Office Jacksonville, Florida Gentlemen: As consulting engineer for the Minmi Water Company and at various times for the City of Miami Beach since 1920, the Jacksonville Water Supply Cormmission in 1927, War Depart- ment as a member of the Board of Eagineers and Geologists which reported on Ground Water related to the Atlantio-G-ulf Ship Canal and now for the Department of Water and Sawers, City of Miamij, I have been actively engaged in studies of ground and surface water resources of Florida, especially those within Dade County, for more than twenty-five years. The attached brief statement for the record of the 11 July 1946 hearing on the petition of Dade County for permit to control water levels in the Minmi Canal is respectfully subanitted at the request of the Department of Water and Sawers, Cityr of Miami. Very truly yours (Signed) Mdalcolm Pirnie Malcolm Pirnie M~P:nb Brief Statement Descriptive of Ground WPa~ter Reservoir in Dade County and Immediate Need for Protective Wlater Level Controls with particular reference to M~iami and Tuniamij Canals General Immediately under a strip of land, approximately twenty miles wide east of Biscayne Bay shore line (Exhibit 1 blue and red areas) there exists a wedge shaped mass of very porous rocks, thin along the wresterly edge and slightly more than one hundred feet thick along the Bay shore. The surface materials are shallow deposits of sand generally exposed on the higher lands with a muck cover;.nC on the lower lands. This porous mass lies on top of a p:rao-tiedI-ly impervious formation several hundred feet thick wic~iih acts as an effective seal between the younger porous rooks above and the older porous rocks below. (Exhibits 2, 3 wad 4.) A large proportion of tae rainfall on the surface of this porous wedge percolates vertically to the underlying ground water raisiag its surface above sea level. This creates head re- quired to cause slow easterly flow of fresh water to escape into sea water near the shore of Biscayne Bay. Eere the fresh-water neets the movable sea water east wiall of the ground water re- servoir (Exhibits 3 and 4) flowing upward from the bottom and lower depths in the reservoir in the contact zone between fresh water and the west face of the movable sea-water wall. At the west face and over the crest of the movable wall, sea-water is depressed forty units below sea level for each unit of fresh water head above sea level. The fresh-water carrying varying mixtures with sea-water discharges through tche porous Bay bottom close to sea level in a variable zone or band automatically adjusted ia width to permit the existing volume of fresh wliater flow to escape. Natural and artificial channels out through the Bay shore ridge move the fresh-water escape band inland. In these circumstances high ground water levels resulting from heavy rains must flow laterally for considerable distances through porous rooks to discharge through the limited perimeters of the channels until the rest of the movable sea-water east wall of the ground water reservoir can be forced eastward through the porous rooks th reestablish an adjustable escape band in the Bay bottom along the shore line. Obviously the existence of a moderate number of such channels causes substantially higher ground water levels during periods of heavy ratus than would occur if the adjustable rest of the movable sea-water east wall of the reservoir were maintained at the shore line of the Bay. While channels out through the Bay shore ridge cause increased ground water levels in wet periods they also cause substantially lower ground water, levels in extended droughts. With little or no recharge from rainfall and continuous drainage of fresh water stored in the rooks above sea level the storage is depleted month by month and the fresh water pressure against the movable east wall of the reservoir is reduced. Ihis wall moves wrestw~ard seeking a pressure balance. Rate of movement is limited by friction of flow of salt-water westward and of dis- placed fresh water seeking escape to sea level through the sides and bottoms of the channels. Channels of substantial width and moderate depth be- came tidal surge ways in dry seasons when fresh water flows are small. Flood tides project a wedge of sea-water surging in- land on the bottom. The displaced fresh water flows over the sea- water wedge in the opposite direction as its level is raised. This causes considerable mixing at the interface and same back flow of salted water into the surface waters of the ground water reservoir un-til solid matter clogs the open pores in the channel sides and bottom. Ebb tides withdraw the sea-water wedge followed by the backed up fresh and salted mater mixture. As the level falls past mean sea level to approach lowr tide level ground water dis- charge from higher elevations is resumed. This forces the solid matter away fron the pores to permit flown into the channel. The ground water drainage effect is similar to that of a tidal basin controlled by checkr valves closed against flood tides and opened to discharge on ebb tides. The resulting depletion of ground water storage augmented slightly by pumping from wells had, on May: 19, 1945, reduced its surf ace elevation close to and even below nean sea level over substantial areas at Mfiami Springs and from Perrine to Royal Palm State Park. Effective adjustment of Great of Movable Sea-WTater East Wiuall of Reservoir Raest~rict'he~ ing F-k~ reashatr Dis~cha-rge during Droughts Water table contours (Exhibi~t 5) record the steepest slopes for easterly flows from the ground water highs immediately north and south of the Mbiami Canal under the Bay shore ridge. Depth of fresh water above the sea-water rest of the east wall of the reservoir may have then been reduced to one percent or less of the depth of fresh water to the wost of the wall. Thus the greater part of flow fran ground water storage above sea level at that time was westerly toward seepage discharges to canals and the cone of depression caused by pumping water fron Mdiami Springs well field. The area colored yellow is that under which movement of" ground water was toward Nuanu Springs and the blue arrows indicate the directions of converging flows. Westward Advance of the Movabl e Sea--Waer East Wall of Reservoir Fron its natural location approximating Biscayne Bay shore line the west face sone of mixing of the movable sea-water eas-t wall of the ground water reservoir has moved inland under the area colored red (Exhibit 1). Salients of the advance are 'established under the numerous tidal drainage canals of which the Miami Canal is obviously the most menacing. Existing "improve- ments" of this anal, solely in the interests of tide water shipping, have doomed to bi-section this essential ground water reservoir of Dade anid Broward counties. Each successive "'improve- 'mentn of the Miami Canal has accelerated the northwesterly march of sea water under it. Miami's original water supply was from flowing wells on the Miami Country Club grounds nlearS. W. Tenth Avenue and a natural water fall in the Miami River. The pure, good quality water flowed by gravity in a pipe line laid in the river valley to the electric power station where it wvas putmped without trea~t- ment iuto the distribbi-tion system. The initial Miami Canal con- verted the MSiami River and falls into a tidal section but con- structled two small boat looks upstream fotning the second pool level above high tide near Miami Spring~s. The wells stopped flowing and purmps wuere installed to lift water from then to the receiving basin for continued gravity flow to the power station. Salt water contamination of the well water started at the timel of the first W~orld War and Mr. H. H. Hymanr, then manager of' the Miani W~ater Company, was sent to jail for serving the people water containing salt in concentrations of only about 200 PPH as 01. For a few years salt-free water was obtained f~ran wells drilled at increasing distances north of the canal. In the year 1924 it was determined to establish a new ground water production area above the second looks near Hialeah. A legislative bill to permit use and maintenance of the new source of supply was vetoed by the governor anid the City of Miami assumed responsibility for development and operation of the source of water supply. Almost immediately the Miami Canal was deepened and extended as a tidal channel to .Penuoo. The resulting sea-water salient is still on its westward march. A concentration of one- sixth sea-water has already reached NJ. W, 38'th Street. Fran this location, in spite of intermittent use of temporary dana, tongues of sea-water contaminated ground water have already lashed north- westward into the Miami Springs well field at times of law ground water levels as reobrded on February 29, 1944.~ (Exhibit 6). On the bottan of the ground water reservoir the sea- water intruder is always pres~en~t with his rear supported by occupa- tian of the voloane of the reservoir already conquered, and the re- -3- aulting resistance to retreat offered by increasing distances for sea-water flow eastward through the porous rooks. When pressure of the Fresh water wanes to less than that required to balance sea- water at- reservoir bottom elevation the intruder creeps. forward un- til balance of pressure is again established, ThE'u the proportion of the total time during which cer- tain fresh water control levels are maintained is the most important factor in permitting advance or causing retreat of the sea-water intruder. For enrample, if the fresh water level in the Mdiamd and Tamidami Canals is controlled as low as elevation 1.5 for more than half the total time ultimate heavy salting of the existing Mliani Springs Well field may be anticipated. (Exhibit 7). M~os-t Effective Controls Possible to Recapture and Preserve Freda~ Groun~d Wiater Resource Fortunately the bottan of the reservoir slopes downmward fron its shallow westerly edges generally with increasing slopes, until it reaches its location under the Bay Ridge, Dams should be constructed as close as possible to the Bay shore, high enough to hold back the maximan flood tides, where all channels out through the ridge and fresh water level controlled by the dams at or close to mpean high tide level for as great a proportion of the total time Bthepo'saible. The movable sea-water east wall of the reservoir would then be gradually forced back to its natural position with crest close to the Bay shore line. In these circumstances practically full depth of the reservoir would be available for lateral flow of ex- oess volumes of fresh-water seeking discharge over the sea-water orest- into the Bay. The sea-water salients surrounding the tidal sections of the canals and obstructing flow of fresh water over them to discharge into the canals would be rapidly depressed. This would increase effectiveness of existing canals for fresh ground water withdrawal when heavy rains cause relatively high levels. With canal sections adeq~ia~te for the drainage required, ground water levels can be controlled within desired limits much more effectively than is possible under present conditions. Higher level storage should be provided in the shallower half of the ground water reservoir by secondary controls in all connecting drainage channels. Such storage will extend the time when it is possible to hold canal water levels at elevation 2.5 and may need to be su~p- plemented by Lake Okeechobee storage drawn at times through connect- ing canals. This plan of control was included ia the 1940 proposal for development of a source of ground water supply near the Broward County Line for Mdiami Beach. It included double controls in Bia- cayne and Snake Greak Canals and reinstatement of effective control at the looks in North New River and South NJew River Canals in Browvard County. -4- Essential Need for Conservation -of All So'-uTrces of Stisfactor~ Waer South of Latitude of North Shore of' Lake Okeechobee Very low land levels, correspondingly great distances to the Atlantic and Gulf coasts and lack of porous rooks near sea level in which an underground lateral drainage system could develop have confined highly nineralized conate waters under most of the land area. Fresh waters from the rainfall naturally spread out and flow in shallow broad depressions to discharge their unevaporated surplus as surface water flows to the ocean and gulf, Canals dredged through the area which draw water below natural surface levels nor drain to them some of these oonate waters which cause marked depreciation in quality, during dry weather flows. (ExhibJit 8). Dry season evaporation from Lake Okeechobee removes water at a rate in excess of' 2,000 c.f.a. and the shallow storage remaining is definitely limited to provide large quantities of water fbr various uses during periods of extended droughts. Narrow belt of porous rooka meeting the ooean water at and near sea level :provide substantial capacity for lateral flow of water in the pores to escape near the shore line, Such washing of the rooks hars dissolved their more soluble substances and has dis- charged the solutions and oonate waters into the oc ean, (Exh ibit 8 Blue Area), This type of cleansed ground water storage. reservoir was available under the area colored blue on the southerly east coast of Florida. One large reservoir extended south from Lake Worth and another smaller one north fran ~Jupiter Inlet. Both have been substantially depleted in capacity by surface drainage opera- tions. The full capacities of these reservoirs are needed as the only available covered storage basins in which fresh water fran the rainfall can be collected anid held for use during many months with few if any rains. The bulk of the fresh water stored in the reservoirs is needed fran at least 2.5 feet above sea level to the bottom to hold their seo-water east walls at the shore line. S~atorage available foEi?;atbrer applysl irrigation and leakage through the east walls is only that volume above elevation 2.5. There is no loss by evaporation fron the reservoir surfaces over the greater parts of their areas where the water table is below the reach of capillarity and roots of growing plants. The relatively low land covering of the reservoirs limits the depths of storage available for use. This is no greater than needed to support the population and activities which will be established in this Florida east coast area within a reasonable future period of time if the present trend in growth continues. It would be a orine to permit the fortunes and industryq~of so large a group of citizens to be invested in the area unless adequate steps are taken immediately to reestablish and protect these natural ground water storage reservoirs. Ship and Boat Looks at Sea Water Contact D-esigined alnd Operated to Keep Canal Water Fresh Model tests recently completed by Anny E~ngineers at Vicksburg, Miss. have demonstrated the feasibility of design and operation of looks to prevent serious salting of anal waters. In the sea level chambers when the sea gate is closed at least a half look full of fresh water is admitted at the surface Phile an eq~ual quantity of salt water is withdrawn evenly over the bottom. The water in the sea level chamber is practically fresh whien the canal gate is opened. Water from an upstream sump :'u the canal bottan is also withdrawn to discharge salted water which may pass over the canal bottom aill. This is an essential use of available fresh water supply. Water for this purpose in the M~iasri Canal might be furnished in part through canals connecting with Lake Okeechobee. NJ. W. Twentieth Street Lodat~ion for M~iami Canal Look Location of the proposed look at the temporary dan site near N. W. Thirty-Sixth Street would not provide the necessary factor of safety to prevent ultimate salting of the Mbiiamib Springs well field even with another look built on the Tamiami Canal close to its connection. with the Miami Canal. Furthermore,water levels above both looks would have to be controlled at or above elevation 2.5 at all times. It is obviously preferable as a means of preventing sa- water contamination of the well field at Miami Springs to adopt the recommended location near N. W. Tw~rentieth Street as petitioned by Dade County. at this location also water level above the look should be controlled at elevation 2.5 except when heavy rains cause such large volume of flow as to require full look openings to effect its dis- charge . If this N. W. Twoentieth Street location is the nearest to the Bay shore which can be approved at this time it should be authorized at once and built immediately. It will be useful as a second level look when the Bay shore self-flushing look is built as it should be in the immediate future. Acknowledgments This statement would not have been possible without the splendid recordings of the excellent studies made by the Un~ited States Geological Survey during the past six years. All of the attached exhibits are copies of a few selected records of this great work. They have been colored to emp~hasize the brief d~escrip- tions presented. Discussions of controlling principles of the prob- lem with Mr. Parker and Mr. Bogart have aided materially in visualizing the operations of these coastal ground water reservoirs. -6- Inspections and consultations with t he engineers of the United States Departneint of Agriculture, Soil. Consenra- tion Service have contributed greatly to a growing understanding of the over-all problems of desperately needed waiter control in Florida. k)RLE /Ih AS&@PP STATENEN~~T OF 00mRTY ENGINEER EARLE M. RADER AT TBE U. S. ENGINEER EIEARIN'G ONE THE PROPOSED MIAMI CANAL LOCK July 11, 1946 My name is Earle M., Rader. I am County Engineer for Dade County, Florida and as such an in charge of Dade County's WCater Control Program. In general the water control program being carried out by Dade County has as its objectives the stopping of salt water intrusion into the fresh water, and where possible, the re-establishment of fresh water in areas that have gone salt, together with the control of the fresh water table in farm lands so as to make such lands more suitable for farmijng. In the case of peat soils we propose to prevent their burning and reduce their oxidization and thereby preserve such peat soils. As Commissioner Peters has outlined, preliminary to taking the action we are now taking, the U. S. Geological Survey in cooperation with D~ade County, -has carried on an extensive study of the water control pro- blema in this county. The U. S. Department of Agriculture, the Florida Experimental Station, U. S. Weather Bureau, the Everglades Drainage District and numerous other agencies (local, state and Federal) have cooperated. Tais investigation revealed a serious salt water encroachment up the streams and canals and particutlarlyr up the Miami Canal where this en- creacknment affects the city of MBiami water supply well fields. As a result of this investigation it was deemed essential to take positive action to correct the situation; the County was organized as a water control dis- trict and I set up, under my directions a staff for that specific purpose, headed by John C. Stephens, W~ater Control Enegineer, who will be heard from later. |
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