Prep Quiz Part 2
A big problem on Connecticut's shoreline is "shoreline hardening". What best describes this process?
building of human-made infrastructure on the coast
In what year was the last volcanic eruption with a Volcanic Explosivity Index of 6?
1991
Geological processes that are ultimately the result of climate can also be predicted, for example: erosion rate. Using average erosion rates and projecting that forward, it is possible to predict that the Grand Canyon has ceased to exist about ________ years from now.
2,000,000
The oldest archaeological site in Connecticut is approximately how old in years?
12,500
Of all the asteroids and meteorites that impact Earth, where did most of them originate from?
Asteroid belt
Which, if any, is considered a High Hazard Potential dam?
Eagleville Dam
Which Hominin species is associated with the oldest evidence for controlling fire?
Homo erecrtus
Watch this video about the US High Plains/Ogallala Aquifer. What best describes the reason that water resides on the High Plains / Ogallala aquifer?
It is essentially fossil water from a former climate regime
What happens when soils are irrigated with water containing lots of easily dissolved cations (i.e., positively charged ions)?
Soil becomes elevated in its concentration of salts in the soil, which causes dehydration of the soil.
Erosion is a common form of land degradation, but it is also entirely natural. Below you see two maps of the United States, one with natural erosion rates and the other with cropland (agricultural) erosion rates. Which of the following statements is TRUE? i. Under natural conditions, erosion rates are the highest in mountainous areas. ii. Under natural conditions, continental average erosion rates are about 21 meters per year.
Statement i is true
The UN does not predict this global population change to happen equally around the world. According to the table below, where in the world is the population growth expected to be the largest in the 21st century? (both in sheer numbers as well as percentage)
Sub-Saharan Africa
Megathrust Earthquakes can only happen at what type of tectonic setting?
Subduction zones
Why does humanity have little control over things like Earthquakes and Volcanoes?
The geothermal energy that drive these forces are too great
The American Dust Bowl displaced millions of people in the USA and Canada. This is an example of what type of land degradation from the Table in Question 4?
Wind erosion
Another goal of installing the reef balls at Stratford Point was to initiate colonization by natural reef builders, such as oysters. The figure below shows the location of the reef balls and the total number of oysters observed on the artificial reefs. Would you say that the goal to increase colonization of oysters was achieved?
Yes, in particular on the seaward most reefs
There is a lot of uncertainty associated with sea-level projections, as you can see if you toggle between different "scenarios" on ther interactive map on the NASA website. These uncertainties arise in part because of uncertainty in how the climate system responds to changes in the future, but actually most projection uncertainty is the result of uncertainty how political and socio-economic scenarios may evolve in the future. To oversimplify: some scenarios project an optimistic political and socio-economic future, and others pessimistic ones. For example, go back to the sea level projection tool and find Bridgeport again. When you click on it, then click on "full projection". Now you see a graph of one scenario with climate system uncertainty included. You can toggle between different scenarios and when you hover your mouse above the graph you can see different projections per decade. In the year 2100, what is the difference between the medians of the most optimistic and the most pessimistic scenarios?
about half a meter (almost 2 feet)
What was the first important colonial environmental impact to America's rivers?
beaver trapping
Mountaintop Removal is associated with what type of extraction?
coal
Coal forms by burial and ______________, whereas oil forms by burial and _____________.
compression of plants, compression of marine phytoplankton
"Vimpact" indicates the speed at which 101955 Bennu (1999 RQ36) would be traveling as it entered our atmosphere, in other words, the its speed relative to Earth right before impact. Let's put this speed into context. 101955 Bennu (1999 RQ36)'s impact speed is approximately ___________. (Hint: use Google Maps to answer this question)
covering the distance between UConn and Tolland in one second
The Park River in Hartford was once a _________ and is now a __________.
flowing stream, sewer
The size of a volcanic eruption is in an inverse correlation with its frequency, meaning the bigger a volcanic eruption is, the rarer. Study the table below. What do we estimate the recurrence interval is (globally) of a volcanic eruption the size of the Hunga Tonga eruption in January 2022?
once every decade to once every century
The Neolithic Revolution refers mainly to ______.
origin of agriculture
The threat of near earth objects like asteroids and comets is due to
physical impacts
This question relates to the figure in Question 5. One nuance that the authors of this paper point out in their own data has to do with the total population of New England. It represents an "impossible experiment". Fill in the blank: A fully controlled experiment testing pre- and post-colonial disturbance by humans in New England should have _____ population sizes at pre- and post-colonial times, since otherwise it's not possible to exclude the possibility that it's just population size that controls disturbance, independent of colonialism.
the same
When a species "Overshoots" or exceeds it's population carrying capacity, is an example of?
unsustainability
Using a rate of change, a projection can then be made of sea-level changes in the future. On this website, NASA allows you to view projected sea-level changes for different scenarios at different locations. Look up, for example, what the Total Sea Level rise is in the year 2100, for scenario SSP3-7.0 (in other words, do not change the data map options) for Bridgeport Connecticut? (give your answers in meters, but only write down the NUMBER, not the units)
.89
According to the Table in Question 4, which types of land degradation are linked to agriculture, including livestock? (select all that apply)
Bush encroachment Degradation of tropical peat soils Deforestation Overgrazing Wind erosion Soil erosion
What is the type of star that the Sun turns into as it gets older and starts to grow in size?
Red giant
According to the graph in Question 10, how often is an impact with the energy of 101955 Bennu (1999 RQ36) expected to happen?
Roughly every 10,000 years
Energy released by a meteorite often gets measured in "megatons of TNT equivalent", meaning the mass of TNT that you'd have to explode to get the same amount of energy release. 101955 Bennu (1999 RQ36)'s potential energy is "1.4e+3 Mt", which means 1,400 Megatons of TNT equivalent (a Megaton is a million tons). That sounds like a lot, but still quite hard to conceptualize. Below you see a table in which energy released by Earthquakes is represented in the same way, with other explosive comparisons added as examples. 101955 Bennu (1999 RQ36)'s potential energy is approximately equivalent to __________.
a magnitude 8 earthquake, larger than the largest thermonuclear weapon
The January 2022 Hunga Tonga-Hunga Haʻapai eruption is estimated to have had a Volcanic Explosivity Index of 5, and is (likely) the largest eruption thus far of the 21st century. (note that it takes a while for volcanologists to crunch the numbers and therefore the Volcanic Explosivity Index, as well as the exact ranking of size, is still being evaluated) Study the table below. What is the volume of ejecta associated with a volcanic eruption of that size? (ejecta in this context refer to particles such as ash and other pyroclastic material that a volcano spits up)
A billion to 10 billion cubic meters
This website has a map with observed meteorite impacts for the last 500 years. The meteorites are sorted by mass (in grams). Has a meteorite impact the size of 101955 Bennu (1999 RQ36) (or larger) been observed in the last 500 years?
No
One dam that is not on the Army Corps of Engineers Inventory is the dam on Mirror Lake on the UConn campus that blocks off Robert's Brook. Before the dam was built, a swamp existed where Mirror Lake is now. According to this article, what was the primary reason for creating Mirror Lake?
Recreation
Look at the graphs again in Question 5. Which of the following observations can you make about the data?
the relative abundance of weeds was higher during colonial times than during pre-colonial times fire activity was higher during colonial times than during pre-colonial times
Let's try to put the hazard posed by 101955 Bennu (1999 RQ36) in context. A famous landmark in Arizona is Meteor Crater, also known as Barringer Crater (see picture below). It's an impact crater from a meteorite that hit during the Pleistocene epoch, about 50,000 years ago. The crater has a diameter of a little over a kilometer. How does the size of the Barringer crater meteorite compare to 101955 Bennu (1999 RQ36)?
101955 Bennu (1999 RQ36) is about ten times larger
As the Coursebook points out, population overshoot is a problem, both for living in equilibrium with our environment, as well as being able to sustain ourselves in our environment. The United Nations (UN) is particularly concerned with this latter aspect and therefore attempts to model the world's population growth and investigate nuances thereof. To try and predict the world's population, they incorporate changes in birth rates, mortality rates, economic prospects, etc. especially as these three are known to relate to eachother. Let's look at some of their data. Below is a graph that shows the main results of their predictive model. Note that it was published in 2019. Which of the following is TRUE about their predictions?
By the year 2100, world population is expected to exceed 10 billion people By the year 2100, world population growth rate is expected to be near or at 0%
Which of the following volcano types do we only know from geologic evidence, but have no observations of in modern times?
Flood basalt volcano
A Supervolcano eruption is an eruption with a Volcanic Explosivity Index of 8. When and where did the last Supervolcano eruption occur? (select TWO, one for time and the other for location)
New Zealand 26,500 years ago
This question relates to the map in Question 24. In what climate type is it more likely to find endorheic basins?
dry climates, like deserts
Today the timing of peak snowmelt runoff in New England streams is happening _____ than it typically occurred historically.
earlier
According to the article, what are local problems that came along with the building of this dam? (select all that apply)
ecosystem change (disappearance of the swamp) poor water quality it is catagorized as a High Hazard Potential dam sediment accumulation
This question refers to the graphs in Question 5. What does the "± 1SD" stand for on the y-axis of each graph?
it stands for "plus or minus one standard deviation", it indicates measurement uncertainty
One form of apocalypse preventing nuclear was/is abbreviated MAD, short for
mutually assured destruction
The 2010 Haiti Earthquake was _____, considering the geologic history of the location
not without precedent
The volcanic eruption of the Hunga Tonga-Hunga Ha'apai volcano in January 2022 was extremely explosive and violent. Based on the table below, which of the following do you think was also associated with this volcanic eruption?
the rock that formed from this eruption was rich in Silicates and was light colored there was a relatively high amount of water dissolved into the magma the lava was not very viscous (it had trouble flowing)
The Solar System has three orbital paths with asteroids, comets and other meteoroids: the Kuiper belt, the Asteroid belt and the Oort cloud. What is the correct order, from close to far from the Sun?
1. Asteroid belt 2. Kuiper belt 3. Oort cloud
Just like with predictions of future climates and sea-levels, the UN predictions for population growth comes with uncertainties that are quantifiable, but can still lead to an enormous difference between possible outcomes. Have a look at the graph below that shows the projected population growth by geographic location, the dotted lines represent the median predicted change, whereas the shaded areas represent the uncertainty of outcomes. What's the difference in minimum and maximum projected population in Sub-Saharan Africa according to the UN? (give your answer in billions of people, for example write down 6 billion as "6" and 3.4 billion as "3.4")
2
After this, incorporating the uncertainty related to the effect of radiative forcings has actually less to do with how the climate responds to changes in radiative forcing, but more with what policies are adopted. See for example below the graph showing the global surface warming over the next century. The shaded area represents modeled uncertainty, whereas the different colored lines represent different policy scenarios. By the year 2100, what is the Global Surface Warming difference (in degrees C) between the most "optmistic" and the most "pessimistic" scenario?
3.2
The NASA jet propulsion laboratory monitors "Near Earth Objects" with the potential for an Earth impact. Have a look at this website: https://cneos.jpl.nasa.gov/sentry/ When you open it, the table shows you every Near Earth Object (asteroids, comets, etc.) with an impact probability of "1 e-6", which means one in a million to impact in the next 100 years. The Palermo Scale is a measure of the hazard a Near Earth Object might pose to Earth, combining probability of impact as well as the potential energy the Near Earth Object has. Change the dropdown menu for the Palermo scale to ">=-2". This should leave you with only 2 Near Earth Objects. Click on the one that's called 101955 Bennu (1999 RQ36). What is the chance that Bennu will hit Earth in the next 100 years?
About 0.05%
This question relates to the figure in Question 9. How much higher is the cropland average erosion rate than the natural average?
About 30 times
This question refers to the figure in Question 3. But the energy coming directly from the Sun is not the only energy that the Earth's surface receives. What is the other source of energy for the Earth's surface?
Back radiation from Greenhouse Gases
Ocean acidification is the result of excess dissolved _____ in the water.
Carbon
To understand the impact of anthropogenic (human-made) emissions, and be able to predict how changing anthropogenic emissions will affect the climate in the future, climate modelers must first understand the net effect of individual radiative forcings. Below, you see a diagram that constrains the effect of different radiative forcings. Note the error bars associated with each of the forcings. Which of the following forcings have a net warming effect on the Earth's surface?
Carbon dioxide (CO2) Methane (CH4)
Land degradation is an incredibly complex phenomenon. It includes any change in the biophysical potential (for example the number of species a certain amount of area can sustain, or the amount of carbon it can store) of land, due to any combination of human activity. Land degradation is problematic both from a strictly environmental perspective, in that it changes the natural environment and therefore displaces biota, and from a human perspective, in that it might reduce the potential crop yield or affect climate patterns. Problems with land degradation can be feedback systems, as they might be caused by a changing climate and can cause further changes in climate. To further complicate things, the change in climate caused by land degradation, can include temperature increases OR temperature decreases. See for example the table below from Chapter 4 of the IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. Under the column "impact ON climate change", you'll see effects that lead to warming in red, and effects that lead to cooling in blue. Match the forms of land degradation that can lead to warming, cooling or warming AND cooling.
Erosion of agricultural soils B. Warming Overgrazing C. Warming AND cooling Coastal erosion B. Warming Increasing fire frequency and intensity C. Warming AND cooling Sand & dust storms A. Cooling Degradation of tropical peat soils B. Warming
This question relates to the Table in Question 4. The table includes several examples of negative and positive feedback loops in the climate system. A positive feedback loop is reinforcing: the initial change is amplified through the feedback system, for example if warming leads to even more warming OR if cooling leads to even more cooling. A negative feedback loop is weakening: the initial change is muted through the feedback system, for example if warming leads to cooling OR if cooling leads warming. Consider the following examples from the Table in Question 4. Example 1: Increasing global temperatures lead to thawing of permafrost, which releases carbon dioxide and methane, these are greenhouse gases that raise global temperatures. Example 2: Increasing global temperatures lead to increased forest fires, which release ash and soot aerosols, these tiny atmospheric particles reflect sunlight back into space which lowers global temperatures.
Example 1 is a positive feedback loop, Example 2 is a negative feedback loop
Dams and reservoirs have a variety of benefits, but also a range of environmental impacts. There is some movement to demolish dams, especially aging ones. Let's explore some reasons for keeping dams and demolishing dams. Study the following readings: Environmental impact of reservoirs and Dams 101: Why are Dams Built? Match the descriptions with whether they are arguments for keeping, or for demolishing dams.
Flood risk management: catching or releasing water can help reduce flooding up and downstream of the dam B. keeping the dam Water supply: storing water can lessen the impact of a drought or water shortage B. keeping the dam Power generation: falling water is captured by a generator and the released energy can be used for electricity B. keeping the dam Coastal erosion: preventing rivers to bring sediments to the coast leads to heightened erosion rates A. destroying the dam Greenhouse gases: stagnant bottom waters is reservoirs can become anoxic, which will then release methane A. destroying the dam River ecosystems: water storage prevents water from reaching ecosystems downstream, which will then dry out, and it will change the river ecosystem upstream to a lake A. destroying the dam Flood risk management: poor upkeep of dams can increase the risk of dam failure, putting lives at risk A. destroying the dam River ecosystems: a reservoir can generate new habitat for aquatic animals or migratory birds B. keeping the dam
Just like with volcanic eruptions and earthquakes, there is a negative correlation between the size of an asteroid or meteorite impact and the frequency with which they happen. Below is a graph that shows that correlation. Note that the bottom axis shows the same metric we used before "energy released" measured in megatons of TNT. Would 101955 Bennu (1999 RQ36)'s energy cross the "Global Catastrophe" threshold, marked on this graph?
No
Explore the dams closest to the University of Connecticut at Storrs on the Army Corps of Engineers National Inventory on Dams webpage (you can explore these by selecting Connecticut, going to Tolland County and clicking on the individual dams [blue circles] on the map). These are the Hank Hill Pond Dam, the Mansfield Recreation Pond dam, the Eagleville Dam and Mansfield Training Dam 1 & 2. What is the primary purpose of these dams?
Recreation
Based on the information in the graph of question 10 and what you learned last week about supervolcanoes, what has a higher likelihood (or recurrence rate): a catastrophic supervolcano eruption, or a catastrophic meteorite impact?
Supervolcano
Study the map below. What best describes an endorheic basin?
a drainage basin with no outflow to an ocean, and the only outlet is evaporation
Your answer to the previous question might make you wonder what "High Hazard Potential" means in this context. On the "Managing Dams" page, an explanation is given. According to the explanation, what sets a High Hazard Potential dam apart from other hazard potentials?
a high hazard potential dam has a probable loss of human life, in case of dam failure
In order to understand how to make predictions about Earth's climate system, we must first understand a concept called radiative forcing. Radiative forcing refers to components of the earth system that can change the amount of energy from the Sun that reaches the Earth's surface (measured it Watts per square meter). Earth has net positive radiative forcings, meaning that we have more energy in the climate system that we would have if our climate was only determined by solar radiation. This is a good thing too, because without those radiative forcings, Earth's average surface temperature would be about -15 degrees C, or 5 degrees F, whereas now it's closer to 15 degrees C, or 60 degrees F. Radiative forcings are displayed in the diagram below. Solar radiation comes in at the top of the atmosphere, but some of it is lost by being reflected, either by clouds or things at the Earth's surface (like snow). How much energy of incoming solar radiation is actually absorbed at the Earth's surface?
about half
Much like with predicting climate change in the future, uncertainty of population predictions has a lot to do with how political situations and cultures change over time. This video focuses on the data derived from the UN and the uncertainties in population growth in Sub-Saharan Africa in the next century. What are some of the reasons that the video highlights that population growth has declined in many countries and are the source of uncertainty of projections in the 21st century?
access to education access to health care access to contraception
This question relates to the table in Question 4. What is "albedo" and how does increasing albedo lead to cooling?
albedo refers to Earth's reflectivity and increasing albedo means that less sunlight gets absorbed at the Earth's surface
Study the Table in Question 4 once more. What may have contributed to the change in erosion rates seen in Question 11?
all of the above are potential contributing factors
This question relates to the figure in Question 5. The paper in which this data is published argues that "Land managers [in New England] seeking to emulate pre-contact conditions should de-emphasize human disturbance and focus on developing mature forests." Why do you think the authors suggest this?
because the data suggests that pre-contact (pre-colonial) ecosystems were far less disturbed than post-contact (colonial) ecosystems
The graph below shows cropland erosion rates in billions of tons of sediment from 1982 to 2007. What does this graph reveal?
between 1982 and 2007 erosion by both water (sheet & rill) and wind was reduced
The surface area of Connecticut is about 15 billion square meters (5543 square miles). How thick a layer of ejecta could you cover Connecticut in with all the ejecta that came out of a volcanic eruption with a volcanic explosivity index of 5, like the Hunga Tonga eruption?
between 7 and 70 centimeters of ejecta
Which of the following statements is TRUE? i. Tsunamis can form when water is displaced by an undersea Earthquake ii. Tsunamis can form when water is displaced by an undersea volcanic eruption
both statements are true
Study the figure below. Match the processes below with either living shorelines or hardened shorelines.
carbon sequestration A. living shorelines sediment trapping A. living shorelines protection against storms and waves A. living shorelines seaward erosion B. hardened shorelines reduction of habitat and biodiversity B. hardened shorelines
The impact of paleolithic people on the landscape is a hotly debated topic. In 2020, a study was published that amassed data on indicators for human disturbance for 21 archeological sites in southern New England. Below you see some graphs with their results. Things to note: the orange shaded area indicates the colonian period, in other words the arrival of European settlers grey lines indicate data from individual archeological sites, thick orange or green lines are the average across all sites charcoal index is a (dimensionless) indicator for fire ragweed and grasses are used as indicators for weeds, usually the result of deforestation absolute numbers for indigenous populations before the arrival of European settlers doesn't exist, so an index is used What kind of hypotheses can you test with this data? Choose all that apply.
changes in indigenous population index is correlated to fire activity and the relative abundance of weeds fire activity is significantly different between colonial and pre-colonial times the relative abundance of weeds is significantly different between colonial and pre-colonial times
The last volcanic eruption with a Volcanic Explosivity Index of 7 was the Mount Tambora eruption of 1815. Eruptions with a Volcanic Explosivity Index of 6 or higher have the capability of impacting global climate, because of the sheer amount of ash that they eject into the atmosphere, and the height that the ash reaches. What are some of the consequences associated with the Mount Tambora eruption of 1815? (select all that apply)
crop/harvest failure disruption of monsoon systems epidemics global temperature decrease
Sea-level change is something that is in the news a lot. The nuances, such as shoreline migration, local effects, high-tide flooding, storms, etc., are often lost as we imagine sea-level rise simply as a uniform global process that will sooner or later result in everything being covered by water. So let's look at some of the data, for example: NASA's monitoring of global sea-level rise. NASA has since 1993 used satellites to monitor sea-level, but before that used tidal gauges from around the world. Have a look at the two graphs on the website. What does it show you?
global sea-level has risen about 100 milimeters (roughly 4 inches) since 1993 and 200 milimeters (8 inches) since 1900
This question refers to the figure in Question 3. What climate modelers do is generate scenarios in which radiative forcings are changed. More energy at the Earth's surface means that the Earth warms up, whereas less energy at the Earth's surface means that the Earth cools down. Can you for example predict which of the following changes in radiative forcings would warm the Earth's surface up?
increased solar radiation decreased reflectivity (albedo) of the Earth's surface
Sea-level changes occur globally, which is known as eustatic sea-level change. However, locally, sea-level changes can differ by a lot, which is known as isostatic sea-level change. Have a look for example at the projections (keep data map options the same again) for: Churchill, Canada (on the Hudson Bay, which is in north-central Canada). Here, a process called crustal rebounding is taking place, as the crust is moving upward after being pushed down by a massive continental glacier a few thousands years ago. Eugene Island, Louisiana (on the Gulf of Mexico). Here, a process called subsidence is taking place, as sediment supply from the Mississippi river is not keeping pace with sediment compaction below. As a result, sea-level is projected to rise _____ at Churchill and _____ at Eugene Island, than in Bridgeport.
less, more
This question refers to the graphs in Question 5. Which of the following are correct about the marshes at Stratford Point, based on the observations presented in the two graphs? (select all that apply)
marshes at both the old and the new reef have surpassed the marsh in Milford in terms of vegetation density marshes at both the old and the new reef have increasing vegetation height marshes at both the old and the new reef have increasing vegetation density
The process of Beach Nourishment a mechanical process to combat coastal erosion. What is being placed on beaches and in nearshore environments with this process?
sediment, such as sand
In the far far future of Earth, the ultimate "solar futures" are also entirely predictable, which involves the life cycle of the Sun and the resulting effects on the Earth. Match the following to the correct time in Earth's future when it's predicted to happen.
the Sun's increasing brightness increases weathering on Earth and paradoxically draws down Carbon Dioxide to a point where most photosynthetic activity is no longer possible about half a billion years from now the Sun's increasing brightness leads to runaway evaporation of the oceans and the end of plate tectonics about a billion years from now any chance of life on Earth, even in the most protected environments, is extinct because of the Sun's increasing size and brightness about 3 billion years from now the Sun reaches it's largest volume and the Earth and Moon are (very likely) swallowed up about seven and a half billion years from now
Which of the following are the major drivers of global (eustatic) sea-level rise, both in modern day, as well in other parts of Earth history?
thermal expansion of seawater melting of continental glaciers
Saying that early humans were in the middle of the food chain means what?
they were both predator and prey
Climate modelers are then capable of looking back in time at known changes in radiative forcings and see how the climate responded to these changes. For example, below is the evolution of radiative forcings since 1750. Above the dark line means that these forcings increase effective radiative forcing, whereas below the dark line means that they decrease effective radiative forcing. Note that the two dotted lines represent actual changes in radiative forcing (black, total) and all anthropogenic radiative forcings combined (red). (ERF = effective radiative forcing, WMGHG = well-mixed greenhouse gases, int. = interaction) Before the Great Acceleration, what is the forcing that seems to have been able to change global climate the most on a year by year basis?
volcanic eruptions
What type of substrate is the most prone to shaking and liquefaction (and therefore destruction) during an Earthquake?
water-saturated sand & mud
Interestingly, while the near future climate is so dependent on politics and culture that is hard to predict, many climatic trends in the distant future are easier to predict, because they rely on predictable astronomical or geological trends. Have a look at the Timeline of the Far Future. Note that for each "event" there are different mechanisms associated with it and therefore different levels of certainty. For example, Earth's orbital variation is cyclical and entirely predictable, whereas the recurrence rate of a supervolcano eruption is simply based on previous rates of eruptions and is therefore not cyclical. Let's look at a few examples. In 15,000 years, the Sahara desert is expected to be much ______ compared to now, because of _________
wetter and more vegetated, cyclical variation in Earth's orbit
Have a look at the Army Corps of Engineers National Inventory on Dams. What is the approximate percentage of High Hazard Potential dams in Connecticut? (only write down a number, do not include the % symbol)
90
The Connecticut Department of Energy and Environmental Protection is involved with several restoration projects of natural shorelines. Here is an interactive website with some examples. At the Stratford Point site, "reef balls" were installed, which are designed to mimic a natural reef and promote growth of natural reef-building organisms, such as oysters, and trapping sediment allowing saltwater marshes to grow behind them. Study the two graphs below. They show density and height of cordgrass, a typical saltmarsh plant, at three sites: 1) "old reef", where reef balls were installed in 2015, 2) "new reef", where reef balls were installed in 2017, and 3) Milford, an existing saltmarsh. Why is the saltmarsh at Milford included here?
It serves as a control group relative to the two experimental set-ups: a place where nothing was changed so that we have a baseline for comparison