Bay mud consists of thick deposits of soft, unconsolidated
silt
Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel wh ...
y
clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4).
Clays develop plasticity when wet, due to a molecular film of water surrounding the clay part ...
, which is saturated with
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...
; these soil layers are situated at the bottom of certain
estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environme ...
, which are normally in
temperate regions that have experienced cyclical
glacial
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...
cycles. Example locations are
Cape Cod Bay,
Chongming Dongtan Chongming is an island in the Yangtze estuary north of Shanghai, China. It may refer either to:
* Chongming Island itself
* Chongming District
Chongming District () is northernmost district of the provincial-level municipality of Shanghai. Cho ...
Reserve in
Shanghai
Shanghai (; , , Standard Mandarin pronunciation: ) is one of the four direct-administered municipalities of the People's Republic of China (PRC). The city is located on the southern estuary of the Yangtze River, with the Huangpu River flowin ...
,
China,
Banc d'Arguin
The Banc d'Arguin National Park ( ar, حوض أركين) of Bay of Arguin lies in Western Africa on the west coast of Mauritania between Nouakchott and Nouadhibou and is the former mouth of the Tamanrasset River. The World Heritage Site i ...
preserve in
Mauritania, The
Bristol Channel
The Bristol Channel ( cy, Môr Hafren, literal translation: "Severn Sea") is a major inlet in the island of Great Britain, separating South Wales from Devon and Somerset in South West England. It extends from the lower estuary of the River S ...
in the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
,
Mandø Island
Mandø () is one of the Danish Wadden Sea islands off the southwest coast of Jutland, Denmark in the Wadden Sea, part of the North Sea. The island covers an area of and had 40 inhabitants in January 2018. The island is part of Esbjerg Municipa ...
in the
Wadden Sea
The Wadden Sea ( nl, Waddenzee ; german: Wattenmeer; nds, Wattensee or ; da, Vadehavet; fy, Waadsee, longname=yes; frr, di Heef) is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern cont ...
in
Denmark
)
, song = ( en, "King Christian stood by the lofty mast")
, song_type = National and royal anthem
, image_map = EU-Denmark.svg
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of Denmark
, establishe ...
,
Florida Bay
Florida Bay is the bay located between the southern end of the Florida mainland (the Florida Everglades) and the Florida Keys in the United States. It is a large, shallow estuary that while connected to the Gulf of Mexico, has limited exchange ...
,
San Francisco Bay
San Francisco Bay is a large tidal estuary in the United States, U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, California, San Jose, and Oakland, Ca ...
,
Bay of Fundy
The Bay of Fundy (french: Baie de Fundy) is a bay between the Canadian provinces of New Brunswick and Nova Scotia, with a small portion touching the U.S. state of Maine. It is an arm of the Gulf of Maine. Its extremely high tidal range is th ...
,
Casco Bay
Casco Bay is an inlet of the Gulf of Maine on the southern coast of Maine, New England, United States. Its easternmost approach is Cape Small and its westernmost approach is Two Lights in Cape Elizabeth. The city of Portland sits along its south ...
,
Penobscot Bay
Penobscot Bay (french: Baie de Penobscot) is an inlet of the Gulf of Maine and Atlantic Ocean in south central Maine. The bay originates from the mouth of Maine's Penobscot River, downriver from Belfast. Penobscot Bay has many working waterfr ...
, and
Morro Bay. Bay mud manifests low
shear strength
In engineering, shear strength is the strength of a material or component against the type of yield or structural failure when the material or component fails in shear. A shear load is a force that tends to produce a sliding failure on a mater ...
, high
compressibility
In thermodynamics and fluid mechanics, the compressibility (also known as the coefficient of compressibility or, if the temperature is held constant, the isothermal compressibility) is a measure of the instantaneous relative volume change of a ...
and low
permeability, making it hazardous to build upon in
seismic
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...
ally active regions like the
San Francisco Bay Area
The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Gov ...
.
Typical bulk density of bay mud is approximately 1.3 grams per cubic centimetre. Bay muds often have a high
organic content, consisting of decayed organisms at lower depths, but may also contain living creatures when they occur at the upper soil layer and become exposed by low tides; then, they are called
mudflat
Mudflats or mud flats, also known as tidal flats or, in Ireland, slob or slobs, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. A global analysis published in 2019 suggested that tidal f ...
s, an important
ecological
Ecology () is the study of the relationships between living organisms, including humans, and their biophysical environment, physical environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosy ...
zone for
shorebird
245px, A flock of Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots
Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflats in order to foraging, ...
s and many types of marine organisms. Great attention was not given to the incidence of deeper bay muds until the 1960s and 1970s when development encroachment on certain North American bays intensified, requiring geotechnical design of foundations.
Bay mud has its own official geological abbreviation. The designation for
Quaternary older bay mud is Qobm and the acronym for Quaternary younger bay mud is Qybm. An
alluvial
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Al ...
layer is often found overlying the older bay mud.
In relation to shipping channels, it is often necessary to dredge bay bottoms and barge the excavated material to an alternate location. In this case
chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wit ...
analyses are usually performed on the bay mud to determine whether there are elevated levels of
heavy metals,
PCB
PCB may refer to:
Science and technology
* Polychlorinated biphenyl, an organic chlorine compound, now recognized as an environmental toxin and classified as a persistent organic pollutant
* Printed circuit board, a board used in electronics
* ...
s or other toxic substances known to accumulate in a
benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
environment. It is not uncommon to dredge the same
channel repeatedly (over a span of ten to thirty years) since further settling sediments are prone to redeposit on an open estuarine valley floor.
Depositional scenarios
Bay muds originate from two generalized sources. First
alluvial
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Al ...
deposits of clays, silts and sand occur from streams tributary to a given bay. The extent of these unconsolidated interglacial deposits typically ranges throughout a given bay to the extent of the historical perimeter
marshland
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...
s. Second, in periods of high glaciation, deposits of silts, sands and organic plus
inorganic
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemis ...
detritus
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commu ...
(e.g. decomposition of estuarine
diatoms) may form a separate distinct layer. Thus bay muds are important time records of glacial activity and streamflow throughout the
Quaternary period.
Some depositional formation is quite recent, such as in the case of Florida Bay, where much of the bay mud has accumulated since 2000 BCE, and consists of primarily decayed organic material. In the case of Florida Bay these bay muds can accrete as much as 0.5 to 2.0 centimeters per annum, although the dynamic equilibrium of
erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is di ...
,
wave action
In fluid dynamics, a wind wave, water wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result from the wind blowing over the water surface. The contact distance in the direction ...
redistribution and deposition complicate the net rate of layer growth. In the case of the
Bristol Channel
The Bristol Channel ( cy, Môr Hafren, literal translation: "Severn Sea") is a major inlet in the island of Great Britain, separating South Wales from Devon and Somerset in South West England. It extends from the lower estuary of the River S ...
in the United Kingdom bay, mud formation has been occurring at least since the Eemian Stage (known as the
Sangamonian
The Sangamonian Stage (or Sangamon interglacial) is the term used in North America to designate the last interglacial period. In its most common usage, it is used for the period of time between 75,000 and 125,000 BP.Willman, H.B., and J.C. Frye, ...
Stage in
North America), or about 130,000 years ago. In other cases such as with
San Francisco Bay
San Francisco Bay is a large tidal estuary in the United States, U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, California, San Jose, and Oakland, Ca ...
, deposition has been interrupted by sea-level changes, and strata of vastly different vintages are found. In the San Francisco Bay Area, these are called Young bay mud and
Older bay mud by
geologist
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, alt ...
s. Human activities can also affect deposition; close to half of the Young Bay Mud in San Francisco Bay was placed in the period 1855–1865, as a result of
placer mining
Placer mining () is the mining of stream bed ( alluvial) deposits for minerals. This may be done by open-pit (also called open-cast mining) or by various surface excavating equipment or tunneling equipment.
Placer mining is frequently used for ...
in the
Sierra Nevada
The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...
foothills.
Geotechnical factors
Construction on bay mud sites is difficult because of the soil's low strength and high compressibility. Very lightweight buildings can be constructed on bay mud sites if there is a thick enough layer of non-bay-mud soil above the bay mud, but buildings which impose significant loads must be supported on deep foundations bearing on stiffer layers below the bay mud, or obtaining support from friction in the bay mud. Even with deep foundations, difficulties arise because the surrounding ground will likely settle over time, potentially damaging utility connections to the building and causing the entryway to sink below street level.
A number of notable buildings have been constructed over bay muds, typically employing special mitigation designs to withstand seismic risks and settlement issues. Complicating design issues, fill (beginning about 1850 AD) is sometimes found deposited on the surface level. For example, the
Dakin Building
The Dakin Building is an architectural award-winning class A office building on the San Francisco Bay in Brisbane, California. Serving as a corporate headquarters building for several companies of national prominence, it was built from the profi ...
in
Brisbane, California was designed in 1985 to sit on piles 150 feet deep, anchoring to the
Franciscan formation
The Franciscan Complex or Franciscan Assemblage is a geologic term for a late Mesozoic terrane of heterogeneous rocks found throughout the California Coast Ranges, and particularly on the San Francisco Peninsula. It was named by geologist Andre ...
, below the bay muds and through an upper fill layer. Furthermore, the structure's entrance ramp has been set on a giant hinge to allow the surrounding land to settle, while the building absolute height remains constant. The Crowne Plaza
high-rise hotel
A hotel is an establishment that provides paid lodging on a short-term basis. Facilities provided inside a hotel room may range from a modest-quality mattress in a small room to large suites with bigger, higher-quality beds, a dresser, a ref ...
in
Burlingame, California
Burlingame () is a city in San Mateo County, California. It is located on the San Francisco Peninsula and has a significant shoreline on San Francisco Bay. The city is named after diplomat Anson Burlingame and is known for its numerous eucal ...
was also designed to sit over bay muds, as was the Westin Hotel in
Millbrae, California
Millbrae is a city located in northern San Mateo County, California, United States. To its northeast is San Francisco International Airport, San Bruno is on its northwest, and Burlingame on its southeast. It is bordered by San Andreas Lake ...
and
Trinity Church in Boston's Copley Square. Indeed, Boston's entire
Back Bay district is named for the tidal bay that it now covers.
Logan International Airport
General Edward Lawrence Logan International Airport , also known as Boston Logan International Airport and commonly as Boston Logan, Logan Airport or simply Logan, is an international airport that is located mostly in East Boston and partially ...
and the
San Francisco International Airport
San Francisco International Airport is an international airport in an unincorporated area of San Mateo County, south of Downtown San Francisco. It has flights to points throughout North America and is a major gateway to Europe, the Middl ...
are also constructed over bay mud.
Mudflats
When the mud layer is exposed at the tidal fringe, mudflats result affording a unique
ecotone
An ecotone is a transition area between two biological communities, where two communities meet and integrate. It may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and gras ...
that affords numerous shorebird
species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
a safe feeding and resting habitat. Because the muds function much like
quicksand
Quicksand is a colloid consisting of fine granular material (such as sand, silt or clay) and water. It forms in saturated loose sand when the sand is suddenly agitated. When water in the sand cannot escape, it creates a liquefied soil that los ...
, heavier
mammalian
predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
s not only cannot gain traction for pursuit, but would actually become trapped in the sinking muds. The muds are also an important substrate for primary
marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found a ...
productivity including
eelgrass,
cordgrass and
pickleweed. Furthermore, they are home to a large variety of
molluscs and estuarine
arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
s. Richardson Bay, for example, exposes one third of its areal extent as mudflat at low tide, which hosts a productive eelgrass expanse and also a large shorebird community.
Mammals such as the
Harbor seal
The harbor (or harbour) seal (''Phoca vitulina''), also known as the common seal, is a true seal found along temperate and Arctic marine coastlines of the Northern Hemisphere. The most widely distributed species of pinniped (walruses, eared s ...
may use mudflats to haul out of estuary waters; however, larger mammals such as
humpback whale
The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hum ...
s may become accidentally stranded at low tides. Note that normally humpback whales do not frequent estuaries containing mudflats, but at least one errant whale, publicized by the media as
Humphrey the humpback whale, became stuck on a mudflat in San Francisco Bay at Sierra Point in Brisbane, California.
Worldwide occurrences
Bay muds occur in bays and estuaries throughout the temperate regions of the world. In
North America, prominent instances are: (a) the Stellwagen Bank formed 16,000 to 9000 BCE by glaciation of
Cape Cod Bay in
, (b) Florida Bay, (c) in California Morro Bay and San Francisco Bay and (d) Knik & Turnagain Arms in Anchorage, Alaska. In the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
large bay mud occurrences are found at
Morecambe Bay
Morecambe Bay is a large estuary in northwest England, just to the south of the Lake District National Park. It is the largest expanse of intertidal mudflats and sand in the United Kingdom, covering a total area of . In 1974, the second large ...
,
Bridgwater Bay and Bristol Bay. Straddling
Denmark
)
, song = ( en, "King Christian stood by the lofty mast")
, song_type = National and royal anthem
, image_map = EU-Denmark.svg
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of Denmark
, establishe ...
, the
Netherlands
)
, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
and
Germany
Germany, officially the Federal Republic of Germany (FRG),, is a country in Central Europe. It is the most populous member state of the European Union. Germany lies between the Baltic and North Sea to the north and the Alps to the sou ...
is the
Wadden Sea
The Wadden Sea ( nl, Waddenzee ; german: Wattenmeer; nds, Wattensee or ; da, Vadehavet; fy, Waadsee, longname=yes; frr, di Heef) is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern cont ...
, a major formation underlain by bay muds.
In Asia the
Chongming Dongtan Chongming is an island in the Yangtze estuary north of Shanghai, China. It may refer either to:
* Chongming Island itself
* Chongming District
Chongming District () is northernmost district of the provincial-level municipality of Shanghai. Cho ...
Nature Reserve in
Shanghai
Shanghai (; , , Standard Mandarin pronunciation: ) is one of the four direct-administered municipalities of the People's Republic of China (PRC). The city is located on the southern estuary of the Yangtze River, with the Huangpu River flowin ...
,
China is an example of a large scale bay mud formation. The
Atlantic coast of
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
holds the
Banc d'Arguin
The Banc d'Arguin National Park ( ar, حوض أركين) of Bay of Arguin lies in Western Africa on the west coast of Mauritania between Nouakchott and Nouadhibou and is the former mouth of the Tamanrasset River. The World Heritage Site i ...
, a
World Heritage
A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...
nature preserve in the country of
Mauritania. Banc d'Arguin is a vast area underlain by bay mud.
Regulatory issues and actions
When building on top of bay mud layers or when dredging estuary bottoms, a variety of
regulatory
Regulation is the management of complex systems according to a set of rules and trends. In systems theory, these types of rules exist in various fields of biology and society, but the term has slightly different meanings according to context. Fo ...
frameworks may arise. Normally in the United States, an
Environmental Impact Report as well as a geotechnical investigation are conducted precedent to any major construction over bay mud. Combined, these reports have developed much of the data base extant on bay mud characteristics, frequently yielding original field data from soil borings. These data have demonstrated that in many locations the shallower bay muds contain concentrations of
mercury,
lead
Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate ...
,
chromium
Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.
Chromium metal is valued for its high corrosion resistance and h ...
, petroleum
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
s, PCBs,
pesticides and other chemicals which exceed toxic limits: a geological record of human activities of the last century. These data are particularly important to consider when dredging of bay muds is contemplated as part of a development project. Such dredging can have impacts to receiving lands as
soil contamination
Soil contamination, soil pollution, or land pollution as a part of land degradation is caused by the presence of xenobiotic (human-made) chemicals or other alteration in the natural soil environment. It is typically caused by industrial activit ...
, but also
water column
A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...
impacts from sediment disturbance.
In the case of dredging within the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...
, a permit is almost always required from the
, after submission of extensive data on the project limits, chemical properties of the bay muds to be disturbed, a dredge disposal plan and often a complete
Environmental Impact Statement pursuant to the
National Environmental Policy Act
The National Environmental Policy Act (NEPA) is a United States environmental law that promotes the enhancement of the environment and established the President's Council on Environmental Quality (CEQ). The law was enacted on January 1, 1970.U ...
. Further review by the
United States Coast Guard
The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mu ...
would normally be required. Within individual state jurisdictions, such as
California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...
, an Environmental Impact Report must be filed for dredging of any significance; furthermore, agency reviews by the
California Coastal Commission and the
Regional Water Quality Control Board
The California State Water Resources Control Board (SWRCB) is one of six branches of the California Environmental Protection Agency.
History
This regulatory program has had the status of an official government department since the 1950s. The Sta ...
would normally be mandated. All of these regulatory bodies serve an important role in deciding whether an area may be dredged or not. However, the most important body is
CEQA, or the California Environmental Quality Act. This guiding legislation is the reason for
Environmental Impact Reports, costly mitigation measures and arduous review processes. One of CEQA's main goals is to promote interagency cooperation in the review process of a project. This is one of the main reasons why it is the overseer of all projects in California.
For buildings proposed over bay mud layers, typically the municipality involved will, in addition to the usual engineering and design review issues common to all building projects (which are more complicated because of the site conditions), require an Environmental Impact Repor
This process would include reviews by that city's building department, as well as applicable regional and state agencies such as those cited above for dredging projects, except that Coast Guard agencies would not typically be concerned. In developing in California, proposed development over bay mud layers would also have to go through a planning commission and a city council in order to be allowed. This process would respect the EIR, CEQA, and all the other bodies discussed above. In the case of San Francisco the project would have to get approved by the San Francisco Board of Supervisors.
In regards to San Francisco, some interesting negative externalities are being experienced due to the dredging of land by the Bay. The Millennium Towers, which were completed in 2008, are currently sinking. This has had a negative impact on the residents of this building. In response to this subsidence, San Francisco's city attorney has decided to file a lawsuit against the developer, because the developer failed to inform the residents of the accelerated speed that the building was sinking at. If this lawsuit results in success for San Francisco this could lead to policy changes being made in the future surrounding transparency between developers and potential buyers of the developed land.
Sea level rise
Sea level rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
will have a huge impact on the ecosystems surrounding and within bays all across the globe. Sea level rise in California will completely engulf bay mud that makes up
San Francisco Bay
San Francisco Bay is a large tidal estuary in the United States, U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, California, San Jose, and Oakland, Ca ...
. In order to deal with sea level rise the California Coastal Commission has adopted policy guidelines to help California.
See also
*
Estuary
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...
*
Glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...
*
Liquefaction
In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics.
It occurs both naturally and artificially. As an example of t ...
*
References
External links
U.S. Fish and Wildlife Service article on bay mud and environmental features for part of the San Francisco Bay perimeter
{{DEFAULTSORT:Bay Mud
Types of soil
Aquatic ecology
Estuaries
Marine biology
Sediments
Environmental chemistry
Environmental soil science
Morro Bay
San Francisco Bay
Diatom biology