Misplaced Pages

#486513

97-455: The part of the lagoon that is traditionally called "Biscayne Bay" is approximately 35 miles (56 km) long and up to 8 miles (13 km) wide, with a surface area of 221 square miles (570 km). Various definitions may include Dumfoundling Bay, Card Sound, and Barnes Sound in a larger "Biscayne Bay", which is 60 miles (97 km) long with a surface area of about 271 square miles (700 km). Hernando de Escalante Fontaneda related in

194-547: A barrier island and Miami on the mainland , from Dumfoundling Bay on the north to the Rickenbacker Causeway to the south. Other municipalities on the western shore of the lagoon include Aventura (on Dumfoundling Bay), North Miami Beach, North Miami , and Miami Shores . Municipalities bordering the lagoon on the barrier islands north of Miami Beach include Sunny Isles Beach, Bal Harbour , Bay Harbor Islands , Surfside , and Indian Creek Village . North Bay Village

291-595: A causeway and bridges connecting Key Biscayne to the Ragged Keys and beyond on the grounds that such construction would block the free outflow of storm surges from the bay across the flats to the ocean. It is believed that it does moderate the effects of storm surges on the bay. The transportation of sand southward along the Atlantic Coast of Florida by longshore drift ends in the area of the Safety Valve. The structure of

388-408: A drop in the ground surface. In unconsolidated aquifers, groundwater is produced from pore spaces between particles of gravel, sand, and silt. If the aquifer is confined by low-permeability layers, the reduced water pressure in the sand and gravel causes slow drainage of water from the adjoining confining layers. If these confining layers are composed of compressible silt or clay, the loss of water to

485-402: A former lake bed, has experienced rates of subsidence of up to 40 centimetres (1 foot 4 inches) per year. For coastal cities, subsidence can increase the risk of other environmental issues, such as sea level rise . For example, Bangkok is expected to have 5.138 million people exposed to coastal flooding by 2070 because of these combining factors. If the surface water source

582-1070: A global level, although priority chemicals will vary by country. There is a lot of heterogeneity of hydrogeologic properties. For this reason, salinity of groundwater is often highly variable over space. This contributes to highly variable groundwater security risks even within a specific region. Salinity in groundwater makes the water unpalatable and unusable and often occurs in coastal areas, for example in Bangladesh and East and West Africa. Municipal and industrial water supplies are provided through large wells. Multiple wells for one water supply source are termed "wellfields", which may withdraw water from confined or unconfined aquifers. Using groundwater from deep, confined aquifers provides more protection from surface water contamination. Some wells, termed "collector wells", are specifically designed to induce infiltration of surface (usually river) water. Aquifers that provide sustainable fresh groundwater to urban areas and for agricultural irrigation are typically close to

679-408: A home and then returned to the ground in another well. During cold seasons, because it is relatively warm, the water can be used in the same way as a source of heat for heat pumps that is much more efficient than using air. Groundwater makes up about thirty percent of the world's fresh water supply, which is about 0.76% of the entire world's water, including oceans and permanent ice. About 99% of

776-518: A lagoon behind the ancient reef that became the Key Largo limestone, and is the same age as the Key Largo limestone. The limestone bottom of the lagoon is overlain by 1.2 to 4.6 metres (3.9 to 15.1 ft) of sand, carbonate mud, and coral rubble sediments. For purposes of discussion and analysis, Biscayne Bay is often divided into three sections: North Bay, Central Bay, and South Bay. The North Bay of Biscayne Bay principally lies between Miami Beach on

873-623: A location in the Florida Keys. Due to its distance from the open ocean and the restrictive passages between other components of Biscayne Bay, Manatee Bay experiences low tidal exchange, while the C-197 canal allows fresh water from the C-111 canal to flow into Manatee Bay. Salinity levels in Manatee Bay range from 14 parts-per-thousand (ppt) to 45 ppt (seawater has an average salinity of 35 ppt). In July 2023,

970-519: A long time without severe consequences. Nevertheless, over the long term the average rate of seepage above a groundwater source is the upper bound for average consumption of water from that source. Groundwater is naturally replenished by surface water from precipitation , streams , and rivers when this recharge reaches the water table. Groundwater can be a long-term ' reservoir ' of the natural water cycle (with residence times from days to millennia), as opposed to short-term water reservoirs like

1067-533: A maximum depth of 4 metres (13 ft). The eastern rim of the lagoon is based on an ancient coral reef which existed along the southeastern edge of the Florida Platform about 100,000 years ago. The ensuing Wisconsin glaciation lowered sea levels, leaving the reef above water. The dead reef became fossilized, forming the Key Largo Limestone (commonly called "coral rock"). Key Largo Limestone underlies

SECTION 10

#1732845535487

1164-705: A permanently reduced capacity to hold water. The city of New Orleans, Louisiana is actually below sea level today, and its subsidence is partly caused by removal of groundwater from the various aquifer/aquitard systems beneath it. In the first half of the 20th century, the San Joaquin Valley experienced significant subsidence , in some places up to 8.5 metres (28 feet) due to groundwater removal. Cities on river deltas, including Venice in Italy, and Bangkok in Thailand, have experienced surface subsidence; Mexico City, built on

1261-603: A point between North Miami Beach and Sunny Isles Beach south to the Arsenicker Keys and the Cutter Bank just to the east of those islands. Many discussions about the lagoon include Dumfoundling Bay, a small lagoon just north of North Miami Beach, as part of Biscayne Bay, and include Card Sound and Barnes Sound , in southern Miami-Dade County adjacent to Key Largo , as either part of a system of connected lagoons including Biscayne Bay, or as part of Biscayne Bay itself. The lagoon

1358-626: A second causeway connecting Miami to the barrier islands of Miami Beach, and the County Causeway—;later the MacArthur Causeway —opened on February 17, 1920. In 1925, Biscayne Point was created in Miami Beach's north end. In 1929, a third causeway crossed Biscayne Bay at Normandy Isle , which developer Henri Levy had created several years earlier by dredging and filling the south half of Meade Island. The Julia Tuttle Causeway

1455-671: A small park. It is located on the John F. Kennedy (79th Street) Causeway in North Bay. The City of Miami has many parks fronting on the lagoon, the more important of which are Bayfront Park , Alice Wainwright Park , Margaret Pace Park , Maurice A. Ferré Park , Morningside Park, and Peacock Park . Public marinas on Biscayne Bay operated by the City of Miami include: Dinner Key Marina, Miami Marine Stadium Marina, and Miamarina at Bayside . The Biscayne Bay Aquatic Preserve includes most of Biscayne Bay (in

1552-399: Is a highly useful and often abundant resource. Most land areas on Earth have some form of aquifer underlying them, sometimes at significant depths. In some cases, these aquifers are rapidly being depleted by the human population. Such over-use, over-abstraction or overdraft can cause major problems to human users and to the environment. The most evident problem (as far as human groundwater use

1649-466: Is also subject to substantial evaporation, a groundwater source may become saline . This situation can occur naturally under endorheic bodies of water, or artificially under irrigated farmland. In coastal areas, human use of a groundwater source may cause the direction of seepage to ocean to reverse which can also cause soil salinization . As water moves through the landscape, it collects soluble salts, mainly sodium chloride . Where such water enters

1746-632: Is an additional water source that was not used previously. First, flood mitigation schemes, intended to protect infrastructure built on floodplains, have had the unintended consequence of reducing aquifer recharge associated with natural flooding. Second, prolonged depletion of groundwater in extensive aquifers can result in land subsidence , with associated infrastructure damage – as well as, third, saline intrusion . Fourth, draining acid sulphate soils, often found in low-lying coastal plains, can result in acidification and pollution of formerly freshwater and estuarine streams. Groundwater

1843-472: Is at Black Point. Barnes Sound Barnes Sound is a bay located at the southern tip of Florida , between Key Largo and the mainland. It has been described as part of Biscayne Bay or of the Biscayne Bay System. Two United States Navy warships have been named after the sound. See USS Barnes Groundwater This is an accepted version of this page Groundwater

1940-589: Is bordered on its west by the mainland of Florida, and is separated from the Atlantic Ocean to the east by a string of barrier islands in the northern part of the lagoon, a large shoal in the central section, and the northernmost of the Florida Keys in the south. The lagoon is about 35 miles (56 km) long from Dumfoundling Bay (25° 58′ North latitude) (north of North Miami Beach) to Card Sound, and another 25 miles (40 km) to Jewfish Creek (25° 24′ North latitude), if Card Sound and Barnes Sound are included in

2037-458: Is called the water table . Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps , and can form oases or wetlands . Groundwater is also often withdrawn for agricultural , municipal , and industrial use by constructing and operating extraction wells . The study of the distribution and movement of groundwater is hydrogeology , also called groundwater hydrology . Typically, groundwater

SECTION 20

#1732845535487

2134-417: Is concerned) is a lowering of the water table beyond the reach of existing wells. As a consequence, wells must be drilled deeper to reach the groundwater; in some places (e.g., California , Texas , and India ) the water table has dropped hundreds of feet because of extensive well pumping. The GRACE satellites have collected data that demonstrates 21 of Earth's 37 major aquifers are undergoing depletion. In

2231-412: Is fresh water located in the subsurface pore space of soil and rocks . It is also water that is flowing within aquifers below the water table . Sometimes it is useful to make a distinction between groundwater that is closely associated with surface water , and deep groundwater in an aquifer (called " fossil water " if it infiltrated into the ground millennia ago ). Groundwater can be thought of in

2328-400: Is located on two artificial islands in the middle of the lagoon. North Bay is the part of the lagoon that has been most modified by human works, including channels and other dredged areas, and spoil banks and artificial islands created with material dredged from channels. More than 40% of the area of North Bay had either been dredged or filled to form artificial islands, and more than half of

2425-440: Is now Fisher Island at the south end of Miami Beach . The opening of Government Cut in 1905 separated Fisher Island from Miami Beach and slightly shortened the barrier spit. The dredging of Baker's Haulover Inlet in 1925 across the barrier spit near the north end of the bay converted that part of the barrier spit where Miami Beach was located into a barrier island. Modification of the flow of fresh water through waterways, and

2522-454: Is often cheaper, more convenient and less vulnerable to pollution than surface water . Therefore, it is commonly used for public drinking water supplies. For example, groundwater provides the largest source of usable water storage in the United States , and California annually withdraws the largest amount of groundwater of all the states. Underground reservoirs contain far more water than

2619-468: Is rapidly increasing with population growth, while climate change is imposing additional stress on water resources and raising the probability of severe drought occurrence. The anthropogenic effects on groundwater resources are mainly due to groundwater pumping and the indirect effects of irrigation and land use changes. Groundwater plays a central role in sustaining water supplies and livelihoods in sub-Saharan Africa . In some cases, groundwater

2716-553: Is susceptible to saltwater intrusion in coastal areas and can cause land subsidence when extracted unsustainably, leading to sinking cities (like Bangkok ) and loss in elevation (such as the multiple meters lost in the Central Valley of California ). These issues are made more complicated by sea level rise and other effects of climate change , particularly those on the water cycle . Earth's axial tilt has shifted 31 inches because of human groundwater pumping. Groundwater

2813-433: Is the water present beneath Earth 's surface in rock and soil pore spaces and in the fractures of rock formations . About 30 percent of all readily available fresh water in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water

2910-483: Is the least affected by human activities, although it also suffers from the loss of natural fresh water flow. The Turkey Point Nuclear Generating Station is a significant presence on the mainland shore. Card Sound is an extension of Biscayne Bay to the south of South Bay. Little Card Sound is the next south, separated from Card Sound by Card Bank. The causeway of the Card Sound Bridge now separates Barnes Sound to

3007-400: Is the most accessed source of freshwater around the world, including as drinking water , irrigation , and manufacturing . Groundwater accounts for about half of the world's drinking water, 40% of its irrigation water, and a third of water for industrial purposes. Another estimate stated that globally groundwater accounts for about one third of all water withdrawals , and surface water for

Biscayne Bay - Misplaced Pages Continue

3104-495: Is thought of as water flowing through shallow aquifers, but, in the technical sense, it can also contain soil moisture , permafrost (frozen soil), immobile water in very low permeability bedrock , and deep geothermal or oil formation water. Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults . It is likely that much of Earth 's subsurface contains some water, which may be mixed with other fluids in some instances. Groundwater

3201-452: Is used for irrigation. Occasionally, sedimentary or "fossil" aquifers are used to provide irrigation and drinking water to urban areas. In Libya, for example, Muammar Gaddafi's Great Manmade River project has pumped large amounts of groundwater from aquifers beneath the Sahara to populous areas near the coast. Though this has saved Libya money over the alternative, seawater desalination,

3298-713: The Cutler Fossil Site , a sinkhole that is now a couple of kilometers from the bay. At the time of European contact, in the early 16th century, the area around the bay was occupied by the Tequesta . The Tequesta belonged to the Glades culture , which had been in place for about 2,000 years. The chief town of the Tequesta, also called Tequesta, was on the bay at the mouth of the Miami River, from about 1200. The Miami Circle , just south of

3395-581: The Punjab region of India , for example, groundwater levels have dropped 10 meters since 1979, and the rate of depletion is accelerating. A lowered water table may, in turn, cause other problems such as groundwater-related subsidence and saltwater intrusion . Another cause for concern is that groundwater drawdown from over-allocated aquifers has the potential to cause severe damage to both terrestrial and aquatic ecosystems – in some cases very conspicuously but in others quite imperceptibly because of

3492-673: The University of Miami 's Rosenstiel School of Marine, Atmospheric, and Earth Science are located on the southern end of Virginia Key , the only part of that island bordering on Central Bay. Grove Isle , near the Miami neighborhood of Coconut Grove , is an artificial island in Central Bay. The large marina at Dinner Key is also in Coconut Grove. Central Bay has been adversely affected primarily by bulkheading, urban runoff discharged by canals, and

3589-442: The hydraulic pressure of groundwater in the pore spaces of the aquifer and the aquitard supports some of the weight of the overlying sediments. When groundwater is removed from aquifers by excessive pumping, pore pressures in the aquifer drop and compression of the aquifer may occur. This compression may be partially recoverable if pressures rebound, but much of it is not. When the aquifer gets compressed, it may cause land subsidence,

3686-405: The vadose zone below plant roots and is often expressed as a flux to the water table surface. Groundwater recharge also encompasses water moving away from the water table farther into the saturated zone. Recharge occurs both naturally (through the water cycle ) and through anthropogenic processes (i.e., "artificial groundwater recharge"), where rainwater and/or reclaimed water is routed to

3783-710: The 16th century that a sailor from the Bay of Biscay called the Viscayno or Biscayno had lived on the lower east coast of Florida for a while after being shipwrecked, and a 17th-century map shows a Cayo de Biscainhos , the probable origin of the name for Key Biscayne . The lagoon was known as "Key Biscayne Bay" in the 19th century, finally shrinking to "Biscayne Bay" late in the 19th century. The lagoon has been known by several names. Juan Ponce de León called it Chequescha in 1513, and Pedro Menéndez de Avilés called it Tequesta in 1565. Those names are variant spellings of " Tequesta ",

3880-754: The Biscayne Bay Aquatic Preserves. Card Sound and Barnes Sound lie within the Florida Keys National Marine Sanctuary . The Crocodile Lake National Wildlife Refuge on Key Largo includes 650 acres (2.6 km) of open water in Card Sound and Barnes Sound. Lobsters are protected year-round in the Biscayne Bay-Card Sound Lobster Sanctuary. The sanctuary includes all of the lagoon from a line running from Cape Florida to Matheson Hammock County Park south to

3977-528: The Card Sound Bridge and causeway. The sea level at Virginia Key has been rising at an average rate of 2.97 millimetres (0.117 in) a year from 1931 to 2020, equivalent to 0.97 feet (0.30 m) a century. The islands adjacent to the lagoon are low-lying and threatened with significant flooding in the near future. Gas and oil exploration wells have been drilled near the lagoon, although none reached exploitable deposits. Canals and quarries have disturbed

Biscayne Bay - Misplaced Pages Continue

4074-527: The Eastern edge of the barrier islands and the shoals (Safety Valve) along the northern and middle part of the lagoon. It makes a brief appearance at Soldier Key , in the middle of the Safety Valve, and rises above sea level to the south to form the upper Florida Keys. The western side of the bay has characteristics of an estuary , with 16 waterways, the largest of which is the Miami River , flowing into it. All of

4171-462: The Florida Keys north of Key Largo, are within the boundaries of Biscayne National Park . A number of other state and local parks front on the lagoon, primarily on North Bay and the northern rim of Central Bay. Bill Baggs Cape Florida State Park is located on the southern part of Key Biscayne. Oleta River State Park is located on the south side of the Oleta River where it flows into the segment of

4268-475: The Intracoastal Waterway connecting Dumfoundling Bay and North Bay, fronting on North Bay as it widens to the south. Miami-Dade County operates a number of parks with frontage on Biscayne Bay. Haulover Park is on the barrier island running north from Baker's Haulover Inlet. Crandon Park covers the northern part of Key Biscayne. The Vizcaya Museum and Gardens are located on the mainland in Miami near

4365-568: The MacArthur Causeway have been created, in whole or in part, with material dredged from the lagoon bottom. Most of the islands, such as the Venetian Islands, are residential. Brickell Key , another residential island, is just south of the mouth of the Miami River. Dodge Island , across the main ship channel to the south of the MacArthur Causeway, was enlarged in the 1960s when the Port of Miami

4462-873: The Miami-Dade County-Monroe County line, and from the limit of Florida territorial waters in the Atlantic to the Intracoastal Waterway in Biscayne Bay. When the Biscayne National Monument was upgraded to a National Park, all waters in the National Park were removed from the Biscayne Bay-Cape Florida to Monroe County Line Aquatic Preserve. The remainder of that preserve consists of about 4,163 acres (16.85 km) of submerged lands near Key Biscayne. The two preserves are known collectively as

4559-410: The Safety Valve has been stable for at least the last century. (The area was called Bocas de Miguel de Mora on Spanish maps and derroteros during the era of Spanish Florida .) Stiltsville is a collection of buildings on pilings on several sand flats at the northern end of the Safety Valve. What is now Biscayne Bay was a freshwater basin 4,000 years ago. As the sea level rose, ocean water entered

4656-545: The age of groundwater obtained from different parts of the Great Artesian Basin, hydrogeologists have found it increases in age across the basin. Where water recharges the aquifers along the Eastern Divide , ages are young. As groundwater flows westward across the continent, it increases in age, with the oldest groundwater occurring in the western parts. This means that in order to have travelled almost 1000 km from

4753-405: The aquifer reduces the water pressure in the confining layer, causing it to compress from the weight of overlying geologic materials. In severe cases, this compression can be observed on the ground surface as subsidence . Unfortunately, much of the subsidence from groundwater extraction is permanent (elastic rebound is small). Thus, the subsidence is not only permanent, but the compressed aquifer has

4850-525: The aquifers are likely to run dry in 60 to 100 years. Groundwater provides critical freshwater supply, particularly in dry regions where surface water availability is limited. Globally, more than one-third of the water used originates from underground. In the mid-latitude arid and semi-arid regions lacking sufficient surface water supply from rivers and reservoirs, groundwater is critical for sustaining global ecology and meeting societal needs of drinking water and food production. The demand for groundwater

4947-598: The atmosphere and fresh surface water (which have residence times from minutes to years). Deep groundwater (which is quite distant from the surface recharge) can take a very long time to complete its natural cycle. The Great Artesian Basin in central and eastern Australia is one of the largest confined aquifer systems in the world, extending for almost 2 million km . By analysing the trace elements in water sourced from deep underground, hydrogeologists have been able to determine that water extracted from these aquifers can be more than 1 million years old. By comparing

SECTION 50

#1732845535487

5044-510: The atmosphere through evapotranspiration , these salts are left behind. In irrigation districts, poor drainage of soils and surface aquifers can result in water tables' coming to the surface in low-lying areas. Major land degradation problems of soil salinity and waterlogging result, combined with increasing levels of salt in surface waters. As a consequence, major damage has occurred to local economies and environments. Aquifers in surface irrigated areas in semi-arid zones with reuse of

5141-475: The basin, turning it into an estuary/lagoon. Before the 20th century, a coastal ridge west of and parallel to the bay caused most of the ground water west of the ridge to flow towards the Everglades and Florida Bay , while ground water on the narrow coastal strip east of the ridge flowed into the bay. Freshwater marshes were located all along the western shore of the bay, and fresh water springs were located along

5238-531: The bay was in the news when a bouy there recorded a water temperature of 101.1 °F (38.4 °C). The Safety Valve is a series of shallow sand flats separated by tidal flow channels, stretching about 8 miles (13 km) from the south end of Key Biscayne to the Ragged Keys just north of the Florida Keys . The term "safety valve" was applied to the tidal flats by Ralph Munroe , who argued against building

5335-648: The bedrock on the shores of the lagoon. Miami-Dade County operates a 300-acre (120 ha) landfill at Black Point adjacent to the lagoon. Miami-Dade County operates three wastewater treatment plants close to the lagoon. The oldest is the Central District Wastewater Treatment Plant on Virginia Key. The North District Wastewater Treatment Plant is in North Miami, and the South District Wastewater Treatment Plant

5432-969: The capacity of all surface reservoirs and lakes in the US, including the Great Lakes . Many municipal water supplies are derived solely from groundwater. Over 2 billion people rely on it as their primary water source worldwide. Human use of groundwater causes environmental problems. For example, polluted groundwater is less visible and more difficult to clean up than pollution in rivers and lakes. Groundwater pollution most often results from improper disposal of wastes on land. Major sources include industrial and household chemicals and garbage landfills , excessive fertilizers and pesticides used in agriculture, industrial waste lagoons, tailings and process wastewater from mines, industrial fracking , oil field brine pits, leaking underground oil storage tanks and pipelines, sewage sludge and septic systems . Additionally, groundwater

5529-491: The current population growth rate. Global groundwater depletion has been calculated to be between 100 and 300 km per year. This depletion is mainly caused by "expansion of irrigated agriculture in drylands ". The Asia-Pacific region is the largest groundwater abstractor in the world, containing seven out of the ten countries that extract most groundwater (Bangladesh, China, India, Indonesia, Iran, Pakistan and Turkey). These countries alone account for roughly 60% of

5626-404: The extended period over which the damage occurs. The importance of groundwater to ecosystems is often overlooked, even by freshwater biologists and ecologists. Groundwaters sustain rivers, wetlands , and lakes , as well as subterranean ecosystems within karst or alluvial aquifers. Not all ecosystems need groundwater, of course. Some terrestrial ecosystems – for example, those of

5723-407: The extent, depth and thickness of water-bearing sediments and rocks. Before an investment is made in production wells, test wells may be drilled to measure the depths at which water is encountered and collect samples of soils, rock and water for laboratory analyses. Pumping tests can be performed in test wells to determine flow characteristics of the aquifer. The characteristics of aquifers vary with

5820-472: The geology and structure of the substrate and topography in which they occur. In general, the more productive aquifers occur in sedimentary geologic formations. By comparison, weathered and fractured crystalline rocks yield smaller quantities of groundwater in many environments. Unconsolidated to poorly cemented alluvial materials that have accumulated as valley -filling sediments in major river valleys and geologically subsiding structural basins are included among

5917-404: The globe includes canals redirecting surface water, groundwater pumping, and diverting water from dams. Aquifers are critically important in agriculture. Deep aquifers in arid areas have long been water sources for irrigation. A majority of extracted groundwater, 70%, is used for agricultural purposes. In India, 65% of the irrigation is from groundwater and about 90% of extracted groundwater

SECTION 60

#1732845535487

6014-416: The ground surface (within a couple of hundred metres) and have some recharge by fresh water. This recharge is typically from rivers or meteoric water (precipitation) that percolates into the aquifer through overlying unsaturated materials. In general, the irrigation of 20% of farming land (with various types of water sources) accounts for the production of 40% of food production. Irrigation techniques across

6111-494: The lagoon. The lagoon is 8 miles (13 km) across at its widest point. The lagoon, from Dumfoundling Bay to the Arsenicker Keys, has a surface area of about 572 square kilometres (221 sq mi). The larger lagoon, including Card Sound and Barnes Sound, has a surface area of about 703 square kilometres (271 sq mi). It has an average depth of 1.8 metres (5.9 ft) and, except where channels have been dredged ,

6208-518: The local hydrogeology , may draw in non-potable water or saltwater intrusion from hydraulically connected aquifers or surface water bodies. This can be a serious problem, especially in coastal areas and other areas where aquifer pumping is excessive. Subsidence occurs when too much water is pumped out from underground, deflating the space below the above-surface, and thus causing the ground to collapse. The result can look like craters on plots of land. This occurs because, in its natural equilibrium state,

6305-622: The loss of natural fresh water flow. South Bay is nearly as large as Central Bay, and is defined as extending from the Featherbed Bank to the Arsenicker Keys , or to Cutter Bank, which is to the east of the Arsenicker Keys. (Brown et al. define South Bay as consisting of Card Sound and Barnes Sound.) It is separated from the ocean by the northernmost of the Florida Keys , from Boca Chita Key to Old Rhodes Key . Fresh water sources for South Bay include Black Creek, Goulds Canal, North Canal, Florida City Canal, and Model Land Canal. Tidal exchange with

6402-489: The middle third of the island on the eastern side of Central Bay. Fresh water sources for Central Bay include the Coral Gables Waterway and Snapper Creek . Tidal flow between Central Bay and the ocean is through Bear Cut between Virginia Key and Key Biscayne and across the Safety Valve. The development that has so transformed North Bay has spread over much of the northern shores of Central Bay. Miami Seaquarium and

6499-412: The most productive sources of groundwater. Fluid flows can be altered in different lithological settings by brittle deformation of rocks in fault zones ; the mechanisms by which this occurs are the subject of fault zone hydrogeology . Reliance on groundwater will only increase, mainly due to growing water demand by all sectors combined with increasing variation in rainfall patterns . Groundwater

6596-408: The mouth of the Miami River, has been proposed to be post holes for a structure. The site was abandoned in about 1200, when the town site north of the river was occupied. Juan Ponce de León visited Biscayne Bay in 1513, and Pedro Menéndez de Avilés did so in 1565. Early accounts by Spanish explorers indicated the existence of one or more inlets somewhere on the long barrier spit then separating

6693-405: The name of the people who lived around the lagoon at the time. The British, during their occupation of Florida (1763–1783), called the lagoon "Cape River", "Dartmouth Sound", and "Sandwich gulph". Biscayne Bay is a semi- or subtropical lagoon extending most of the length of Miami-Dade County , from North Miami Beach to the upper Florida Keys . Biscayne Bay, in the strictest sense, extends from

6790-540: The north to the Featherbed Bank, which runs across the bay from Black Point to Boca Chita Key . It is separated from the Atlantic Ocean by Key Biscayne , the Safety Valve , and the Ragged Keys , the northernmost of the Florida Keys . It is bordered on the western shore by the municipalities of Miami , Coral Gables , Palmetto Bay , Cutler Bay , and a portion of unincorporated Miami-Dade County. Key Biscayne occupies

6887-514: The northern edge of Central Bay. Matheson Hammock Park , the Charles Deering Estate , and Chapman Field Park are on the mainland along the western shore of Central Bay. Black Point Park and Marina and Homestead Bayfront Park are on the mainland on the western shore of South Bay. Black Point, Crandon, Haulover, Homestead Bayfront and Matheson Hammock parks have public marinas . The county also operates Pelican Harbor Marina, which includes

6984-590: The northern end of Biscayne Bay from the ocean (one called "Boca Rattones" appears on the 1770s map by Bernard Romans), but such inlets open and close over time. At the beginning of the 19th century, there was no inlet through the barrier spit between the New River inlet in Fort Lauderdale and Bear Cut, at the south end of what is now Virginia Key . Hurricanes in 1835 and 1838 opened a new inlet, Narrows Cut (now known as Norris Cut), separating Virginia Key from what

7081-571: The ocean is through Baker's Haulover Inlet , Government Cut , and Norris Cut. Northeast 163rd Street , or Sunny Isles Boulevard, connects North Miami Beach and Sunny Isles Beach across the section of the Intracoastal Waterway running between Dumfoundling Bay and Biscayne Bay proper. Five causeways cross North Bay between Northeast 163rd Street and the Rickenbacker Causeway, including: More than 20 islands in North Bay north from

7178-413: The ocean occurs through Sands Cut, Caesar's Creek and Broad Creek. Boca Chita Key, Elliott Key , and Old Rhodes Key were all enlarged by dredging in the first half of the 20th century. Boca Chita Key was the site of some construction in the early 20th century. Mark C. Honeywell bought the key in 1937, and built a large retreat on the island, including a 65-foot (20 m) tall faux lighthouse. South Bay

7275-671: The open deserts and similar arid environments – exist on irregular rainfall and the moisture it delivers to the soil, supplemented by moisture in the air. While there are other terrestrial ecosystems in more hospitable environments where groundwater plays no central role, groundwater is in fact fundamental to many of the world's major ecosystems. Water flows between groundwaters and surface waters. Most rivers, lakes, and wetlands are fed by, and (at other places or times) feed groundwater, to varying degrees. Groundwater feeds soil moisture through percolation, and many terrestrial vegetation communities depend directly on either groundwater or

7372-582: The opening of Government Cut and the Baker's Haulover Inlet during the 20th century increased the salinity of the lagoon. Dredging of the ship channel and turning basin for the Port of Miami and other navigation channels, including the Intracoastal Waterway , has resulted in the build up of artificial islands in the Northern Bay. As of 1981 more than 40% of the area of North Bay had either been dredged or filled to form artificial islands. Seawalls line almost all of

7469-470: The other two thirds. Groundwater provides drinking water to at least 50% of the global population. About 2.5 billion people depend solely on groundwater resources to satisfy their basic daily water needs. A similar estimate was published in 2021 which stated that "groundwater is estimated to supply between a quarter and a third of the world's annual freshwater withdrawals to meet agricultural, industrial and domestic demands." Global freshwater withdrawal

7566-683: The percolated soil moisture above the aquifer for at least part of each year. Hyporheic zones (the mixing zone of streamwater and groundwater) and riparian zones are examples of ecotones largely or totally dependent on groundwater. A 2021 study found that of ~39 million investigated groundwater wells 6-20% are at high risk of running dry if local groundwater levels decline by a few meters, or – as with many areas and possibly more than half of major aquifers  – continue to decline. Fresh-water aquifers, especially those with limited recharge by snow or rain, also known as meteoric water , can be over-exploited and depending on

7663-524: The remaining lagoon bottom is barren. Coastal wetlands have been almost eliminated in North Bay. Turbidity is high in North Bay due to erosion from spoil islands and banks, and the lack of vegetation on the lagoon bottom. The spoil islands host large quantities of invasive plant species . North Bay is separated from the Atlantic Ocean by barrier islands . Freshwater sources flowing into North Bay include Oleta River , Arch Creek , Biscayne Canal, Little River and Miami River. Tidal flow between North Bay and

7760-423: The same terms as surface water : inputs, outputs and storage. The natural input to groundwater is seepage from surface water. The natural outputs from groundwater are springs and seepage to the oceans. Due to its slow rate of turnover, groundwater storage is generally much larger (in volume) compared to inputs than it is for surface water. This difference makes it easy for humans to use groundwater unsustainably for

7857-408: The shore and on the bottom of the bay. Ralph Munroe noted in the late 19th century that potable water could be pumped from one of those bay bottom springs. Springs can still be found in the bay, but the water from them is now brackish. People lived in the area that is now Biscayne Bay long before the bay was formed. Human bones, teeth, and artifacts that are almost 11,000 years old have been found at

7954-441: The shoreline of North Bay. The bay has been severely affected over the last century by raw sewage releases, urban runoff , shoreline bulkheading , dredging , the creation of artificial islands and the loss of natural fresh water flow into the bay. However, water quality has steadily improved since regular monitoring began in 1979. North Bay accounts for only 10% of the water area of the bay. The first bridge across Biscayne Bay

8051-416: The source of recharge in 1 million years, the groundwater flowing through the Great Artesian Basin travels at an average rate of about 1 metre per year. Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer . This process usually occurs in

8148-469: The south of Key Biscayne on the east, and just to the south of Chicken Key, part of the Charles Deering Estate, on the west. The southern part of the preserve includes Card Sound. The preserve includes about 69,000 acres (280 km) of submerged land owned by the state. The Biscayne Bay-Cape Florida to Monroe County Line Aquatic Preserve was created in 1975. That preserve ran from Cape Florida to

8245-501: The south of Little Card Sound. Manatee Bay is to the west of Barnes Sound. Card Sound and Barnes Sound are bounded on the east by Key Largo . South Biscayne Bay is sometimes defined as including Card Sound and Barnes Sound. Barnes Sound is connected to Florida Bay through a few small channels. Manatee Bay is partially separated from Barnes Sound by Short Key and Main Key. In 1994, it was described as having particularly undisturbed habitat for

8342-497: The subsurface. The high specific heat capacity of water and the insulating effect of soil and rock can mitigate the effects of climate and maintain groundwater at a relatively steady temperature . In some places where groundwater temperatures are maintained by this effect at about 10 °C (50 °F), groundwater can be used for controlling the temperature inside structures at the surface. For example, during hot weather relatively cool groundwater can be pumped through radiators in

8439-408: The unavoidable irrigation water losses percolating down into the underground by supplemental irrigation from wells run the risk of salination . Surface irrigation water normally contains salts in the order of 0.5 g/L or more and the annual irrigation requirement is in the order of 10,000 m /ha or more so the annual import of salt is in the order of 5,000 kg/ha or more. Under

8536-461: The waterways have saltwater intrusion control structures, which restrict the flow of saltwater inland, and regulate the flow of fresh water into the lagoon. Some fresh water enters the lagoon as groundwater flow from the Biscayne Aquifer . All of the bedrock under the lagoon west of the ancient reef, and the adjacent mainland, consists of Miami Limestone , an oolitic limestone that formed in

8633-567: The wider sense) that is not in Biscayne National Park. The preserve was created by the Florida Legislature in 1974, and then included all of Biscayne Bay from the Oleta River to the southern end of Card Sound. The preserve was split into two parts when the Biscayne National Monument became Biscayne National Park. The northern part extends from the headwaters of the Oleta River to the northern boundary of Biscayne National Park, just to

8730-519: The world's liquid fresh water is groundwater. Global groundwater storage is roughly equal to the total amount of freshwater stored in the snow and ice pack, including the north and south poles. This makes it an important resource that can act as a natural storage that can buffer against shortages of surface water , as in during times of drought . The volume of groundwater in an aquifer can be estimated by measuring water levels in local wells and by examining geologic records from well-drilling to determine

8827-420: The world's total groundwater withdrawal. Groundwater may or may not be a safe water source. In fact, there is considerable uncertainty with groundwater in different hydrogeologic contexts: the widespread presence of contaminants such as arsenic , fluoride and salinity can reduce the suitability of groundwater as a drinking water source. Arsenic and fluoride have been considered as priority contaminants at

8924-496: Was built in 1959. Other causeways are the John F. Kennedy (79th Street) and Broad causeways (connecting the Miami mainland), and the Rickenbacker Causeway (connecting Miami to Key Biscayne). The Card Sound Bridge connects the mainland in the Homestead, Florida area to the northern part of Key Largo . Most of Central Bay and almost all of South Bay, as well as the Safety Valve and

9021-486: Was moved there from the mainland north of Bayfront Park. The Miami Marine Stadium was built on the north side of the Rickenbacker Causeway extending from the east side of Virginia Key in the early 1960s. There are also many undeveloped spoil islands in North Bay, such as Sandspur Island and the Picnic Islands . Central Bay is the largest part of the bay. It extends from the Rickenbacker Causeway and Virginia Key on

9118-462: Was partially completed in 1913. The bridge was "hailed as the longest wooden vehicle bridge in the world, and opened up the area as a luxury winter resort and playground." The bridge terminated at the Dixie Highway, built by Carl G. Fisher . The bridge was a toll bridge ; in 1920, the toll was reduced from 20 cents each way (for two-seat cars) to 15 cents one way (and 25 cents round-trip). The bridge

9215-402: Was probably around 600 km per year in 1900 and increased to 3,880 km per year in 2017. The rate of increase was especially high (around 3% per year) during the period 1950–1980, partly due to a higher population growth rate, and partly to rapidly increasing groundwater development, particularly for irrigation. The rate of increase is (as per 2022) approximately 1% per year, in tune with

9312-550: Was sold to the Biscayne Bay Improvement Association, which developed five artificial islands that became known as the Venetian Islands : Biscayne and San Marco in Miami, San Marino , Di Lido , and Rivo Alto in Miami Beach. The bridge was torn down in 1925 and replaced with the "more substantial" Venetian Causeway the next year. The Lummus brothers lobbied for the county commission's support for

9409-525: Was the 2.5-mile (4.0 km) wooden Collins Bridge built in 1912 by John S. Collins and his son-in-law Thomas Pancoast, who formed the Miami Beach Improvement Corporation; financing was provided by Carl G. Fisher and the Miami banker brothers John N. Lummus and James E. Lummus. Construction began on July 22, 1912. Although the cost of the project was initially $ 75,000, the construction project faced delays and cost overruns. The bridge

#486513