Pre-Visit Activities : Urban Sprawl : Background
Third - Fifth Grade Online Curriculum : Communities

Key Points
This section will give you the main information you should know to teach the activity.

Top

Detailed Information
This section gives more in-depth background to increase your own knowledge, in case you want to expand upon the activity or you are asked detailed questions by the students.

Tricounty's 2030 Urban Footprint: Is It Inevitable?
No, it’s not inevitable. First of all, any thirty-year prediction is part science, part guesswork. More importantly, the Tricounty community can take measures to avoid any objectionable aspects of the projection.

The map, however, does describe a 2030 urban footprint that is possible, even probable. More than 500 square miles that is rural now will be developed; a 247 percent increase in land area to handle a population increase of only 49 percent. Moving across the region, new sprawl development would:

This is roughly the picture we will see in thirty years, if current trends in the economy, population growth, and land use policy continue.

At the local level, we cannot do much to affect broad economic and population factors. But the Tricounty community, through its governments and other institutions, can change the policies that control the location and quality of land development. Many tools are available like the private donation of conservation easements and open space incentives in the zoning code. (For a full discussion, see the companion document, "How to Keep the Country in the Lowcountry.) Communities in the region are beginning to use some innovative rural preservation strategies, but implementation is scattered and no community is combining all of the available approaches into a comprehensive package. We can do better.

The Tricounty is different than any other place in the nation, and there is great variety among the communities that make up the region. Consequently, the effort to protect the region’s rural landscape will be homegrown. One thing is certain, however. If we don’t know where our current path is taking us, we won’t know what kind of course corrections to even consider. The 2030 Urban Footprint map provides such a peak at the future.

How to Keep the Country in the Lowcountry
The Greenbelt Education Project
The Greenbelt Education Project includes the three coastal counties that make up the Charleston metropolitan area of South Carolina, namely, Charleston, Berkeley, and Dorchester Counties. The Project seeks to deepen the Tricounty community’s appreciation of, and attachment to, the region’s rural landscape. As currently conceived, the work will last two years, culminating with a major conference.

At the edge of virtually every metropolitan region in the nation, suburban development is consuming rural lands at an alarming rate. This fact was brought home about two years ago, when the Charleston Post & Courier ran side-by-side 1973 and 1994 satellite images of the region emphasizing the urbanized area. The pictures told the story: The population of the metro area had grown a respectable 41 percent, but the urbanized area exploded by 255 percent during the 20-year period.

Such leapfrog sprawl threatens many of the things that make the Lowcountry special:

Experts also have shown that the cost of providing public services to sprawl development exceeds the new tax revenue generated by such development, which places an upward pressure on taxes. Many governmental bodies, private institutions and individuals make thousands of decisions that, taken together, erode the area’s rural assets. With each choice, we trade a piece of the traditional landscape, but the transformation is so gradual that we rarely even notice. The Greenbelt Education Project will help us, as a community, to notice these changes, and to remind us to use our rural places with frugality and intelligence.

Maps provide one important way to convey the necessary information. The Tricounty’s 2030 Urban Footprint map is the first in a forthcoming series. Future maps will highlight specific resources, like fishery grounds or industrial timberlands, to address the interests of specific constituencies.

The Greenbelt Education Project will rely on the communication channels that the supporting organizations use normally: newsletters, meetings, word-of-mouth. Special presentations to groups and opinion leaders will be important, and the greenbelt information will reach a wider audience through the media and an interactive web site.

Available Tools
There is no silver bullet to protecting rural communities and the surrounding landscape from unnecessary suburban development. Instead, only a carefully configured set of relatively small, mutually reinforcing actions can get the job done.

Ironically, any comprehensive strategy to protect the countryside must begin with a positive choice about cities and towns: Where do we want them? Over the next thirty years, the population of the Tricounty will grow by about 250,000 people; roughly the current population of Berkeley and Dorchester Counties combined. These newcomers will need to live, work, and play somewhere. Through our local governments and other institutions, we can identify specific areas to receive the bulk of the new growth. Without such direction, suburban sprawl will spread indiscriminately into the countryside. With a framework of growth areas and rural districts, communities in the region could more easily apply the tools outlined below.

Town Zoning
Put simply, conventional zoning requires sprawl: low-density residential subdivisions, strip commercial centers and office parks connected by ribbons of five-lane highways. Building new neighborhoods along traditional lines, such as downtown Summerville, the Charleston peninsula, the Old Village of Mt. Pleasant, and McClellanville, is a promising alternative. Traditional neighborhood developments (TNDs) offer an excellent quality of life at moderately higher residential densities, as demonstrated by Daniel Island in Berkeley County and I’On in Mt. Pleasant. This efficient use of the available land in town helps relieve pressure to develop further out in the country. For this reason alone, local governments should encourage developers to build TNDs within growth areas. Right now, nearly every zoning code in the region bars developers from doing so.

Concentrate Infrastructure Investments
Public investments in sewer lines, roads, regional high schools and other urban infrastructure invite development. By concentrating public spending within the growth areas, a community can discourage newcomers from scattering across the landscape. Because it costs more to deliver urban services to a dispersed population, this can also reduce the per capita cost of government, minimizing the need to raise taxes. Lexington, Kentucky has had such an "urban service boundary" in place since the 1950s. The Tricounty region’s industrial recruitment strategy, spearheaded by the Regional Development Alliance, takes a similar approach by focusing on areas where infrastructure already exists.

Open Space Zoning
Much of the Tricounty’s rural areas are zoned for suburban development: one or two, even three, houses per acre. That kind of density belongs in town, not in the region’s rural reaches. In response, some communities adopt large-lot zoning, which prohibits rural landowners from dividing their property into lots smaller than fifty acres, for example. Some landowners will opt for very low densities, but to force all rural property holders to do so is unwise. Besides the fact that many property owners would object, only rich people could afford the big lots and the landscape would be carved into "farmettes."

A better strategy, open space zoning (or clustering), allows development without eliminating the defining features of the rural landscape: farmland, timberland and open space. Communities taking this approach allow landowners to subdivide into smaller lots, but also require them to permanently protect 50 percent or more of the original parcel from development. As an incentive, some communities give developers the right to build more if they cluster the houses instead of building on large lots. Charleston County is moving in this direction under its new comprehensive plan.

Donation of Conservation Easements
A conservation-minded landowner can permanently protect property by donating a conservation easement to a land trust. To understand how this works, imagine that the rights associated with land ownership are a bundle of sticks. Each stick in the bundle represents a different right: one to farm and grow trees, one to develop, one to prevent trespass, and so on. A rural landowner can separate the "development stick" from the bundle and give it away to a local group, like the Lowcountry Open Land Trust, or a national organization, like The Nature Conservancy or Ducks Unlimited. The landowner retains all other rights to the land, including the ability to sell or bequeath it. The conservation group holds the easement and makes sure subsequent owners don’t develop. The federal and state governments also lend a helping hand by giving the donor a break on income and estate taxes. Local governments can do their part by making sure that its decisions, such as the location of new sewer lines, do not undermine the easement donors’ perpetual commitment to the rural landscape.

Purchase of Development Rights
Sometimes, rural landowners who want to permanently protect their land from development are not in a position to donate a conservation easement. This often is true of farm families who are "land-rich" but "cash-poor." Government can use public funds to protect at-risk parcels of this type. Rather than acquire land outright, local governments often purchase the development rights associated with the rural parcel, essentially buying a conservation easement. Such a purchase of development rights (PDR) program costs less and keeps the land in private hands. PDR programs must be carefully designed to compliment the work of private land trusts, as well as state and federal efforts to acquire important natural areas. Beaufort County, south of Charleston, recently adopted a PDR program and Charleston County is considering the idea.

Modeling and Predicting Future Urban Growth in the Charleston Area
Jeffery Allen (1) and Kang Shou Lu (2)
1 South Carolina Water Resources Center, Strom Thurmond Institute, Clemson University
2 Strom Thurmond Institute, Clemson University

This project builds upon a study completed by the Berkeley-Charleston- Dorchester Council of Governments (BCD COG), the University of South Carolina and the South Carolina Department of Natural Resources. That study investigated urban growth in the greater Charleston metropolitan area from 1973 to 1994 and found that over the 21-year period, urban land use growth has exceeded population growth by a 6:1 ratio. As South Carolina is targeted as one of the top 10 retirement states in the US, and Charleston one of the top two regions in South Carolina, a fairly rapid growth scenario in the Charleston area is expected. Continued land transformation has certain negative impacts and eventually will fundamentally change the three-county area. This rapid urban growth is a major concern of resource managers, policy-makers and citizens of the State.

The present study, funded by NOAA through the South Carolina Sea Grant Consortium, seeks to model and predict the spatial extent of future urban growth by the year 2030 based on the historical trends of the 1973-1994 study, under the current policy constraints, and the physical environment. It is hoped that such a model will give decision-makers better information from which to implement good growth policy for the BCD area as well as South Carolina.

For the prediction of urban transition probabilities, four techniques including statistical modeling, rule-based modeling, focus group mapping, and integrated GIS modeling were used in the project. Because the size of the region is too large for high-resolution (parcel-based) modeling, analysis units were set to 200X200 meters. All the source data were resampled at this resolution before further processing. Some information losses associated with this resampling were expected.

Under the current modeling scenario, there are two assumptions involved. The ratio of overall urban land use change (255%) to overall population growth (41%) from 1973 to 1994 occurred at a ratio of about 6:1. Since this ratio is one of most important indices of urban growth, it is used here to determine the urban size for the future. For modeling purposes, a slightly more conservative ratio of 5:1 was used to predict future growth. Secondly, it is assumed that population for the three county area will grow to 795,879 by the year 2030 as predicted by projections of the BCD COG compiled with information from the US Census Bureau, SC Department of Commerce and the BCD COG. It should also be noted that the year 2015 road network is embedded in the model, even though the presentation map does not display the new roads; and the prediction does not directly reflect any zoning or land use policy decisions, as it is based on historical on-the-ground changes. In particular, the prediction does not account for new policies recently adopted or under discussion that might limit the extent of future urbanization.

For the statistical modeling, a multivariate logistic regression model was selected because of the non-linear nature of urban growth problems. Urban growth was measured only by change of urban area or urban land use. Urban land use is the dependent variable that is binary while independent variables are a mix of continuous, discrete, and dichotomous variables that represent the major physical, economic, and social factors that have influences on urban growth or land use. A rule-based model was developed to derive the relative transition probabilities of urban growth. This model was designed to complement the pure statistical model primarily through subjective weighting of variables. The third technique used was focus group mapping. The South Carolina Coastal Conservation League (SCCCL) conducted this component of the research. A group of experts, local officials, planners, developers, conservationists and other people who have profound knowledge of the area and urban growth were invited to a number of meetings, or interviewed individually, to express their opinions on where growth may occur during the next 30 years. Finally an integrated GIS model was designed to fully take advantage of the above three models by integrating them into one. In this model, expert prediction was weighted 10% while the other two predictions weighted 45% each in order to eliminate the arbitrary boundary of expert prediction but keep the spatial differentiation of transition probabilities predicted by the logistic model and rule-based model.

If the current growth trends continue and the predictions hold true, the future urban growth will mainly take the pattern of urban sprawl. This has several significant economic, environmental, and social implications in policy-making and urban planning. While these implications are too numerous to list here, their importance cannot be underestimated and the issues cannot be left unaddressed. It is hoped that this modeling project can help inspire decision-makers and citizens to get involved in the planning processes for areas like Berkeley-Charleston-Dorchester.

How does the urban development along watersheds affect the health of tidal creeks in coastal environments?
The coastal areas of the United States contain 17% of the land area, but over 53% of its population. Currently, more than 139 million people live in the coastal areas of the United States and the number continues to rise. In 1960 an average of 187 people lived per square mile in the coastal areas. Today 273 people per square mile live there and it is projected by 2015 that the number will reach 327 people. In the warmer climate of the Southeast, growth has been even more rapid. Since 1960, the population of Charleston County has grown by more than 80,000 people and the populations of both Beaufort County and Horry County have more than doubled.

This rapid growth in population has also resulted in a rapid increase in development. In coastal areas in the United States, an average of 453,000 single-family houses and 303,000 apartment or condominium units are built each year. Development can have major effects on the natural environment by reducing the amount of natural habitat and by increasing the pollution that is produced. These pollutants are often picked up by rainwater and carried into the local watershed, where they can impact the health of local aquatic animals.

In these coastal regions, much of the development occurs on the watersheds of the tidal creeks of the salt marshes. The South Carolina Department of Natural Resources (SCDNR) decided to look into the impacts of development on South Carolina salt marshes. The SCDNR is a state agency responsible for managing and protecting the natural resources of South Carolina. The Marine Resources Division of the SCDNR focuses on the coastal resources of South Carolina and is located at the Marine Resources Center on James Island in Charleston County. Biologists there, realizing development might be having a major impact on the organisms in the tidal creeks of the salt marsh, began conducting research in 1994 to find out what that impact might be.

The biologists began observing tidal creeks in various salt marshes on the South Carolina coast. They observed creeks that drained water from undeveloped, forested areas, creeks that drained suburban areas where more than 45% of the land had been developed, creeks that drained urban areas where more than 75% of the land had been developed and creeks that drained industrial areas where more than 45% of the land was developed for industrial purposes. In total twenty-three tidal creeks were observed between 1994 and 1995, most of the creeks in the Charleston area.

Each creek’s watershed was looked at to see how much and what type of development was on it. Once the creek was characterized as urban, suburban, industrial or forested a number of tests were run on it. Water quality (salinity, dissolved oxygen, temperature and pH) was measured at each creek. Sediment was collected at each creek and analyzed for chemical contamination. Animals were collected at each creek with a seine net and were identified, counted and measured to determine the size, diversity and health of the creek’s biological community. All of this information was recorded so it later could be compared to the other creeks that were observed.

In eight of the creeks, mummichogs, a small fish that is an abundant resident in the tidal creeks of South Carolina, were collected. The mummichogs were examined to determine how healthy they were by examining their immune systems and physiological conditions. These observations were also compared between creeks that were sampled.

After collecting and analyzing the data, the biologists found that development does have an observable effect on the water quality and the health of the animals in the tidal creeks. Tidal creeks that drain from highly developed watersheds were found to have major differences in water quality from those draining undeveloped watershed and were also found to have a higher level of sediment contamination. This had correlations in the health and number of animals that live in the creeks. Animals that were abundant in the undeveloped creeks were found in much smaller numbers in the developed creeks. For example, grass shrimp, an animal common in tidal creeks and very important for the food chain, was found in the undeveloped creeks with an average of about 60 grass shrimp per square meter. In the creeks that drained suburban areas, only about 20 grass shrimp were found per square meter and no grass shrimp were found in the creeks draining urban areas. The health of mummichogs was affected too. Mummichogs found in developed creeks were skinnier and had weaker immune systems than those in undeveloped creeks.

These findings have consequences beyond just the tidal creeks of the salt marsh. When ocean animals spawn, the currents carry the planktonic larvae that are produced inshore to the salt marsh. The salt marsh then acts as a nursery for these young animals, providing food and a relatively safe, stable environment for them to grow in. Approximately 85% to 90% of commercially and recreationally important ocean organisms spend at least part of their life in the salt marsh. The development that has a negative effect on the populations and health of animals that are permanent residents of the salt marsh also impacts the juvenile organisms of the ocean that are there. This in turn will affect the populations in the ocean. If the juveniles are not surviving to adulthood, then the adult population will eventually decline rapidly, as no new adults will be there to replace the old ones.

The results have shown that development can occur in coastal areas, but it has to be done in a controlled manner. If less than 30% of a watershed is developed and covered with impervious surfaces, then the effects on tidal creeks are found to be small. With development over 30% of the land, though, the alterations in the environment of the tidal creeks can be major and detrimental. People continue to want to live in coastal areas, but as this study shows, if we want to preserve the health of our salt marshes and our oceans, ways are going to need to be found to curb the amount of development that occurs there.

Top

South Carolina Aquarium Spotlight
It is too late for the Carolina Parakeet.
You might see a Carolina Parakeet at the aquarium, but it will not be a real bird! The Carolina Parakeet is one of the aquarium’s costumed characters. We have a giant costume that a human puts on and wears around the aquarium. Why did we choose the Carolina Parakeet as one of the animals to represent the aquarium? To the staff at the South Carolina Aquarium, the Carolina Parakeet reminds us how important it is to conserve the habitats found in the state of South Carolina. We want visitors to the aquarium to understand this too. Carolina Parakeets were once abundant here, but now there is not a single one left anywhere on earth. When agriculture began to spread, the Carolina Parakeet began to feed on many of the seeds from fruit and grain crops. Humans thought these brightly colored birds were just pests and many were slaughtered. As human populations increased around the Southeastern United States, Carolina Parakeets became increasingly rare as deforestation (the removal of forests) reduced the habitat in which it lived. The last Carolina Parakeets were seen in Florida in 1920 when a flock of thirty birds were sighted. The Carolina Parakeet, the only native parrot to ever have lived in the United States, is now extinct.

It’s not too late to turn the tide for the Loggerhead Sea Turtle.
The Loggerhead sea turtle is a threatened specie. It is the only sea turtle listed as threatened species; all other sea turtles are listed as endangered. The endangered designation means that the numbers of that animal are so low that, without human help, the animals would not recover and would likely become extinct. Threatened species also have very low population numbers, and so they too must be protected to keep them from becoming endangered.

Loggerhead sea turtles feed on crustaceans, mollusks, jellyfish and occasionally sea grasses and algae. Every two to three years, females return to sandy beaches in the summer to early fall to lay 50 to 300 eggs in a nest. Females reach sexual maturity between 20 and 30 years of age. When they are ready to nest, they will return to the same beaches where they were born. Because turtles are built for the water, they are very slow, sluggish, and awkward on land so they tend to lay their eggs at night. This allows them to be protected by darkness while they are in the vulnerable position of being on land.

Because of development on the beaches where loggerhead sea turtles nest, they now face many problems.  If a female approaches a beach and there are too many bright lights, then she will often turn  around and go back into the water without laying her eggs. Many people build houses, condominiums, and high rises right along the beach. The bright lights from these structures often frighten female sea turtles. More people in an area, sadly, often means that there is more trash present in that area too. If the female starts up a beach and she runs into a lot of trash or a lot of noise she will turn around and go back to the water.

Millions of people enjoy South Carolina’s coastline and waterways everyday. However, many of those people are unaware how their daily activities, from driving a car, to not properly disposing of their garbage, or even throwing a cigarette butt on the ground, can impact the plants and animals off our shores. This debris can harm or kill beach organisms.

As you walk down the street next time, look around. The trash that you may see along the side of the road or on the street will be swept into storm drains the next time it rains. Many storm drains carry water, and the accumulated trash, directly to the ocean. Trash from inland areas is also carried to the sea by rivers, streams, winds. Commercial and recreational boaters contribute to the mess by dumping trash directly into the ocean. Visitors to the beach may be lazy or thoughtless and leave their trash, recyclables, and cigarette butts behind. Where do you think these things go?

Scientists estimate that for every square mile of ocean, there are over 45,000 pieces of drifting plastic. This debris creates major problems for ocean-going animals like sea turtles. Sea turtles can become entangled in items like fishing line, pieces of net, six-pack rings, and strapping bands. This can hamper the turtle’s ability to swim, to dive, and to breathe. Plastic in the water sometimes resembles the jellyfish that is part of the loggerhead's diet. They will sometimes mistakenly eat this plastic, thinking it is a jellyfish. If debris is ingested, sea turtles may feel like they are full and thus fail to eat; they die of starvation. 

Loggerhead sea turtles, like many other marine turtles, are very specific on which beach they will lay their eggs. As hatchlings, baby turtles imprint on "their " beach by smelling the sand and feeling the texture of the sand on their faces. When a female comes to the edge of a beach she first smells the sand and feels the texture to see if it the right beach, if not she will keep searching for her beach. Researchers have reported that some females actually make nests within a few hundred yards of where they were hatched. Presently beach-going is very popular and erosion has and continues to affect some of the more popular beaches. In some cases, cities will take sand from one beach or from under the water and put it on another beach to create a bigger beach. This confuses the female turtles and they become unable to recognize the beach on which they were born.

Loggerhead Sea Turtle Fun Facts:

Status In SC: has been classified as threatened since 1978 (the only sea turtle that is not classified as endangered); protected by the Endangered Species Act