Statement to The Public works mbcmittee of the Appropriations Omittee of the United Stetea Senate April 13, 1960 in behalf of the Bequest of the State of Florida for a Reconnaissance Study of Flood Control and. Hate:- Conservation Needs of The Rithlacoochee River, The Oklamha River, The Peace River, The Hillsbomugh River, and AdJaeent wtershede in west Central Florida by John N. Wakefield, Director Florida Department of Water Resources Tallahassee Florida Kr. Chaimn: The Florida Congressional Delegation through the Honorable Speasard L. aolland, a member or this counittee, and the Honorable George A. anther-a, members of the Senate of the United States from Florida, has already placed before this Submittee a request for an appropriation of $100,000 to pay for a study by the U. S. W Corps of Engineers of the need for, and the beat means by which to accoaplieh, flood control, water conservation and other water resource benefits in an area of West Central Florida. -2- The tree in which the atudv in deaired is shown on Figure l of this eteteeent. It encompasses an eras of none 10,823 square miles or approxi- mately 20 percent of the surface area of the State of Florian. The aree is defined by the drainage basins of the four mJor stream: stunning m e comeon, interconnected. system of headwaters known locally es the Green M. The major stream are the Withleooochee River, the Wench: Rivor, the Billehoroueh River and the Peace Hirer. Lying between these major river basin: and the shore of the Cult of lbxico are a umber of wall Itrelu which have much the em flood and drought problem es their larger neighbor-e and which experience prectically the cue veether conditions. It is proposed, therefore, that the one of study shall be all of that area of Florida lying vest and south of the eastern and norther houndriee of the watershed: of the Ulthlacooehee and (klevahe Rivera on the north and the tidal enters of the Gulf of nice and its tributariee on the vest. The study area shall not include my 01 the lends presently in the pmJect me of the Central and Southern Florida Flood Control District. Thin study hed been requested on the heeie of the need for VIth control as demonstrated first by critical leke end strea- conditions experienced in these areas during the drought years of 195L195? and secondly by revere flood Mange experienced during the Vet year of 1958 end the unusually vet year of 1959. Since that request was filed, however, as recently he lid- bIrch 1960, e lei-3e pert of the proposed project area wee subjected to the met severe flooding that has ever been recorded in thet ares. Flood deluge in 1959 was eetimeted to have exeeeded $5,000,000. Theee floods resulted from reinfadl which, for may stations in this me, exceeded any other 12-month period in the more than 60 years of record. do under tropical storm: occurred during 1959. Ming the min-perch Item of 1960, the eree from Tampa Bey to the mouth or the Smnnee River and extending acrose the etete was subjected to e rainfall of 9 to 15 inches in e three-day period. Ground water reservoirs and lakes had previously been filled by modernto heavy rainfall in February and early larch. The effects of the torrential rains wre imediate and devastating. my lurch 22 the nillshorough River hsd erected at e record high, overowing its banks over e wide tree. Thousands of MI residents were forced to leave their home. The poorly drained fletlende lying east of the 'llthlecoochee River, in an cm of new truck farm and cattle ranges, were flooded firet by the heavy rainfall then by the over- floving Hithlecooehee River. lake Apoplus in west Orange County, a tributary of the W RiVer, rose 1.3 feet in three level This wee within three inchee of the top of the protective dike surrounding the rich Zellucod winter vegetable area. lakes Minnelnhe, Barrie, Dore, auntie and Griffin also in the Oldeuahe River Basin, rose to higher stages than any previously recorded. The Oklanha River ovar- flowed its banks throughout its BO-nile length, ceasing millions of dollars of damage to agriculture. -3- Estimates of damage are only partially couplets, but it is already oh- vious that they will exceed $60,000,000. The rm-al areas of Bacon and Sun- ter counties have probably suffered the heaviest proportional damage to their economy. Bone knowledge of the geology of west Central Florida is helpml to an understanding of the water problems of the area. its western section of central Florida is underlain by several thousand feet of limestonos, dolostites, earls, clays and sands deposited in the geologic past when Florida to covered by the ocean. The rocks were origitu de- posited as relatively at-lying beds, but auboequent diriersntial movement of the earth's crust assisted by erosion has caused them to assume their pre- sent rather couple): structure. The configuration or land surface throughout west central Florida is controlled by the geology. The bulk or the material underlying the area consists of the limestones and dolomitea of the Floridan aquifer. These rocks, because of their soluble nature, an extremely porous and pemeahle and are cries-crossed by solution pita, caverns and holes ram: store and tranmit large amounts of water. So. lution of these route has given rise to the amorous lakes and sinks or the area, may of which have penseahle connection; with the underlying limestonea and dolomitea. Water enters the Floridan aquifer in the topographically high area Mall is centered in the Green swamp and extends into adaacent areas. Upon entering the aquifer thmugh sinks, lake bottoms, pen-cable sands or di- rectly where the limestonee and dolomite: are exposed at the sum, the water moves down gradient under Mdrootatio head beneath impemeable beds, generally clays. North and east or the Green Snap recharge area the lineatoues and dolomites of the Floridan aquifer are relatively close to the surface and in places are exposed in stress: banks and around lakes. toward the south, the linestones and dolaaitea are covered by great thicknesses of impermeable clays and clayey sands. north of a line drawn roughly through Tampa Bay and the Green Sump, streams flow, in part. in channels cut in the rocks of the Floridan aquifer. and their low water rim: is maintained by discharge from that aquifer in the form of springs and seeps. South of the line the stream channels are separated {run the Floridan aquifer by varying thicknesses of impermeable clays and, ex- cept for isolated instances lou stream flow: are maintained only by shallow ground-water seepage from surface sands and mat-la. A study of Green Swap will prove especially fruitful because of the no- ique nature or the svaap and its relationship to the tour major stream and the ground water of Central Florida. The swamp lies in a shallow slightly titled bow-shaped area lying in south Lake County. north Polk County, east Pasco county and south Buster Cmmty (gure 2). the drainage or the area to affected by a series of parallel sand ridges. These ridges are remnants of beaches, famed by the alternate rise and fall or the ocean during the past geologic fomtion or peninsular Florida. The serial photographic morale in Figure 3 show the light-colored beaches running in a north and south direc- tion and separated by the dark- colored swampy runs. -u- The area in which Green amp is located is not only the headwaters of the four major surface streams, but is also the highest srtesian pressure area in Smith Florida. The contours on the lover sketch up of Figure it show the elevations to which vater will rise in a well cased through the overlyim impervious strata into the highly pervious Florida: aquifer. This is defined as the piesouetric surmce. A trough in the piesoaetric surface across Florida north of Ocala pre- vents the movement of ground water from north Florida into central Florida. Accordingly, the southern half of Florida is dependent whom on local re- charge to the Floridan aquifer to replace ground water lost to the sea or to the surface through wells and springs. The points of major recharge are the high points or mods in the artesian (piesonetric) pressure system. Since the Green Sweep corresponds to the highest pressure mound in South Florida. it follow that this is a major recharge area. Artesien pressure contour lines are shown in gure 2 in greater detail for the Green Swamp area. The Floridan aquifer from which most of the towns, cities, industries and agricultural areas of Central Florida obtain their water, receives a major portion of its water through recharge in the Green Swamp area. There are case 200 aqmu-e miles of wetlands in the BOO-square mile Green Bump area. It has served until now as a natural reservoir. within the past year sane or this advantage has been lost by attempts to drain the wetlands. If this reservoir can be restored under controlled conditions, both flood control and water conservation benefits may be obtained. It appears to be possible, by means of multiple low-head dams and inter- connecting channels, to store approximately 300,000 acre-feet or water in the amp area. with suitable channels and controls this stored water can be re- leased to one or all four of the major river basins. Similar measures in the upper watersheds or downstream tributaries and on the main streams should make it possible to prevent grossly overloading the capacity of the receiving streams. This vill per-it increases in present capacity without danger of overdrainsge. The small coastal straw referred to earlier are limited in capacity by flat slopes, meandering channels and heavy gmths of vegetation. During tropical stoma they overflov to bring disastrous floods to the areas through which they drain. They also are subject to overdrainage ii' improper flood control seasons are attempted. A reconnaissance survey would permit the detemionion oi the best sp- prosch to a solution or the problems or the entire area. It may well save large sums of money and much loss of tine which might otherwise be commd in a series of studies on individual ones. It will certainly bring encourge- xsent and hope to a thoroughly disheartened and confused segsent or an other- wise progressive and rapidly growing state. Your consideration of these fac- tors is solicited. FDGURE I L lthlh I! on lul'uunn Dill-nu '00:. on! mun-n luau '0 WI! ConlnI run-In ._ u c 1-. . g.-. . -9 -u l . w. v: I FIGURE 3 Aenal Pho1oqmpheofLaho CouMy Showing 1M Headwa'er Lake! of Me Oklaucha River. PRINCIPAL STDiAMS OF FLORIDA PIEZOMETRIC SUPFACE OF IHE FLORIDAN AOUIFER