Natural Shorelines

The Swamp Stomp

Volume 19, Issue 8

After studying the effects of Hurricane Irene on the Outer Banks of NC, scientists faced some surprising data.  The surprising part was that so little information was available on the resilience of coastlines. Environmental Scientist at the University of North Carolina at Chapel Hill, Rachel Gittman, was quoted saying, “The more I researched, the more I realized that we just don’t know very much. So much policy and management are being made without the underlying science.” (1) Scientists understood the physics, but it was never put in a form the policymakers could easily understand. 

As Gittman was studying the shorelines, she noted that concrete walls were out weathered by the marshes. Irene damaged 76% of bulkheads surveyed, while no damage to other shoreline protection options was detected. However, in terms of habitat loss statistics, 30 to 50 percent of wetlands have already been lost, 19 percent of mangroves were lost from 1980–2005, and 75 percent of the world’s coral reefs are now rated as threatened. (3) 

Almost all money, historically, to protect the coastline has been spent on “gray infrastructure.” These include bulkheads, levees, seawalls, and rock revetments.  However, as research on “green” coastal protection is measured in the long term, this is beginning to change. It has become clear that living shorelines are a great defense against storms and surges.   

“Living shorelines” is a term used to define shoreline protection allowing for natural coastal processes to remain through the strategic placement of plants, stone, sand fill, and other structural and organic materials. (4) Yet the value of these ecosystems considered as “green infrastructure” is still not fully accepted or understood by policymakers, and these valuable ecosystems continue to be lost and degraded. Wetlands across the U.S. and the world continue to disappear at a rapid rate due to global warming, increased populations, and infrastructure. 

Storm responses suggest that marshes with and without sills are more durable than hard structures and may protect shorelines from erosion better than bulkheads in a Category 1 storm. Wetlands, i.e. marshes, coral reefs, and mangroves, prevented $625 million of damage during Irene from flooding although 60-90 percent of protective wetlands had been previously lost.  Coastal and marine ecosystems, particularly coral reefs and mangroves can reduce exposure to wind and waves, and they provide natural protection. Coral reefs are the most effective system for flood control. They form natural sea walls where nature intended and, thus, reduce wave energy up to 97%. Reviving reefs and mangrove ecosystems are also more cost-effective than artificial breakwater construction and maintenance.   

After Hurricane Irene, the vegetation in marshes was reduced, but the vegetation only took a year to replenish and become even thicker, and denser than prior to Irene.  However, scientists are now finding that a sill (a berm that is in front of the seaside edge) will bear the brunt of wave energy and will also trap sediment, so the grasses thrive. The marsh floor is sometimes built up as a result.  The sills are green protection and made of hard materials like rock, shells and stone or concrete.  

Along the San Francisco shoreline, restoration is taking on the most novel structure called horizontal levees.  Instead of a vertical wall, horizontal levees are mudflats, marshes, and grasslands that are broad and rise from the edge of the water sometimes hundreds of meters back onto land.  These types of levees are 40% of the cost of a traditional levee.   

NOAA has recently taken living shorelines to the center stage of its coastal resilience plan. 

Some of the recent legislation is: 

  • San Francisco Bay Clean Water, Pollution Prevention and Habitat Restoration Measure passed  in 2016 which allocates $25 million a year for 20 years,  
  • The Living Shorelines Act which designates $20 million in grants to living shoreline work,  
  • North Carolina’s Coastal Resources Commission has approved an easier way to get a living shoreline permit, now comparable to the permit required for a bulkhead, and  
  • Maryland has a strong law requiring property owners to prove the need for a bulkhead as opposed to a living shoreline.  

“Benefit-cost analysis” policy now favors investment in natural infrastructure and coastal restoration may be getting some well-deserved attention. This emphasis should result in federally funded projects in Florida, Puerto Rico and the Gulf Coast. The importance of coastal resilience and natural shorelines will guide development worldwide. “When this happens, it will mark a moment when society realizes nature is not a luxury. It is the future.” (1) 

Sources:

(1) Rowan Jacobsen, “Beyond Seawalls,” Scientific American, Vol. 320 Number 4, April 2019. 

(2) Gittman, Rachel K., “Marshes with and without Sills Protect Estuarine Shorelines from Erosion Better Than Bulkheads during a Category 1 Hurricane,” Ocean and Coastal Management, Vol. 102, Part A, Pages 94-102; December 2014. 

(3) Beck, M.W., Lange, G.M. “Managing Coasts with Natural Solutions: Guidelines for Measuring and Valuing the Coastal Protection Services of Mangroves and Coral Reefs,” World Bank, January 2016. 

(4) Living Shorelines Academy: www.livingshorelinesacademy.org 

Water Usage and Reservoirs

The Swamp Stomp

Volume 19, Issue 5

Water is the single most important chemical required for life on Earth. Animals and plants are both dependent on it and can only survive a matter of days without it. There are many theories as to how water appeared on our planet. It could have come from space as part of the original nebula of gases expanding out after the big bang, possibly from comets and asteroids colliding with our planet, or maybe it was always here and was released from the ground as our planet cooled enough to retain the water. Perhaps, it was a combination of many factors. Whatever the original source, the Earth’s water supply is now essentially constant, with no new water being made or destroyed, just recirculated as part of the hydrologic cycle.

As the population of the world continues growing exponentially, the demand for water for humans, agriculture, and industry is also growing exponentially. Building dams has often been the answer when people need more water. However, the impact of dams on the water supply is unsustainable.

The history of population growth in Las Vegas is a perfect example. Many decades ago the city was growing tremendously and the population was expected to reach 400,000 by the year 2000, so a pipeline was built to Lake Mead above the Hoover Dam in Nevada. This, in turn, created a false sense of abundance of water and the population grew almost four times higher than what was predicted.

Dams give communities a false sense of security because they cover up the natural phenomena of droughts that often occur in the heat of the summer. People don’t feel the impact of the droughts, so their water usage remains constant, rather than considering rationing. In a similar way, the city of New Orleans was built behind a levee. While the levee can sustain small floods, it could not hold off a large storm like Katrina. The city was built on a floodplain and the levees created a false sense of protection from floods.

The US began constructing dams after World War II and construction in the US reached its peak during the 1960s.  Currently, though, the rate for decommissioning dams now exceeds the rate of new dam construction.

A previous article in the Swamp Stomp mentioned some of the drawbacks of building dams on rivers, such as the effects on water quality, and increased contamination, but a “dam-building boom” is happening in developing countries today. Western funding agencies are pushing the construction of dams in underdeveloped countries although the social and environmental impacts may outweigh the benefits.

Building dams in the Middle East has caused disastrous shortages downriver in many countries. Dams on the Euphrates River in Turkey have cause water shortages in Iraq and Syria. Dams on the Colorado River impact downstream cities in Mexico, leaving a dry riverbed in some cases.  Many years, the Colorado never even reaches the ocean. The cause and effect of such impacts are obvious. People in wealthy countries don’t envision the repercussions of their actions on others that are outside their realm of thought.

Climate change is also affecting the Earth’s water supply.  Rising sea levels could mean that saltwater could intrude into groundwater and our drinking supplies, especially in low-lying coastal areas, making the water undrinkable. Flooding due to extreme rainfall would cause sewers to overflow, also contaminating our fresh drinking water resources. These are just a few of the effects of climate change on our water supply.

The irony is that with 70% of the Earth covered in water, there really is no shortage of water. The problem is that 97% of it is salt water, and of the 3% that is freshwater, 2% is locked up in glaciers and in the polar ice caps.

The alternative seems simple enough: conserve water. Water saved by installing water-efficient fixtures and appliances in the home and in industry can reduce water use by 20%.  Just finding and repairing leaks in homes and in municipal distribution systems, could increase the water supply by 900 billion gallons a year, equivalent to the annual consumption for 11 million homes.

One example of how conservation can help can be seen in the cities of Phoenix, Los Angeles, San Diego, and Albuquerque. They would not be able to sustain their increasing populations without current reservoirs, however, due to conservation measures; the usage of water in the Southwest has remained flat since the 1980s, regardless of the rising populations.

Besides conservation, another method for easing water shortages is to capture and retain more rainwater. Captured rainwater is a great source of clean water that can be used for many things like watering lawns and gardens, washing, and toilet flushing, not to mention drinking water.

Seventy percent of freshwater used globally is used for irrigation. This usage that can have a tremendous impact on our water supply especially since it has been shown that half of the water used in irrigation doesn’t even get to the crops. Newer sprinkler and drip-irrigation technology uses much less water and reduces the “non-beneficial” consumption by 54% and 76% respectively.

Dams and reservoirs are not a bad solution, but the social, environmental, and economic costs and benefits should be evaluated for their long-term effects. As the population continues to rise, global warming will continue to impact our water cycle, and dams will continue to be built. There really is no one solution to this problem but unless people take a more active role in conservation and invest themselves in protecting the world’s water supply, some day, the faucets may just run dry.

1. Gies, Erica, “Do Dams Increase Water Use?,” Scientific American, Feb. 18, 2019, https://www.scientificamerican.com/article/do-dams-increase-water-use/

2. Nicklow, John W., Water Encyclopedia. http://www.waterencyclopedia.com/Da-En/Dams.html

Dams and Rivers – Maybe not a Good Fit

The Swamp Stomp

Volume 19, Issue 4

Rivers and streams are an integral part of the hydrologic cycle of water that occurs throughout the world, transporting rainwater from river basins upstream, to locations downstream and ultimately to the oceans. Along the way, they support fish and wildlife habitats, provide us with drinking water and irrigation, and help provide recreation and other useful functions. When a dam is built on one of them, for whatever reason, the equation changes. There are many obvious and but also sometimes subtle changes to ecosystems. For example, the increased transmission of malaria has been directly linked to dam construction in reservoirs in Southeast Asia and Africa.

Through 2015, dams have disrupted the flow of water to more than half of Earth’s major rivers with approximately 57,000 large dams being built. Millions of people worldwide have been displaced by the construction of dams, in the name of flood mitigation, hydroelectric power, water storage, and recreation.

The loss of forests, wetlands, and wildlife through inundation is one obvious effect of dams. Another effect is that by eliminating the natural flooding of an area we are affecting its ecological balance and this can cause major shifts in species diversity or even the possible loss of a species as in the case of the Tellico Dam project in Tennessee and the endangered Snail Darter.

A contamination problem that is pervasive in reservoirs is the accumulation of high levels of mercury in fish. Mercury is harmless in its organic form, occurring naturally in soils, but decomposing organic matter can transform this mercury into a toxic form called methylmercury. Methylmercury passes up the food chain and becomes dangerously concentrated. Levels of methylmercury in large fish at the top of the food chain can be high, and human consumption of these fish can cause central nervous system poisoning.

Dams affect the deposition of sediment downstream and within the reservoir. The sediment that would normally flow downriver now gets piled behind the dam. The disruption of the natural flow and deposition of sediment downstream leads to increased erosion of the riverbanks and streambeds for hundreds of kilometers downstream from the dam.  Silt from floodwaters deters erosion of delta wetlands and is instrumental in the dispersal of organic nutrients from the outflow of rivers. Without the floodwaters making their way to these natural landforms, the salinity can increase downstream. This has a severe impact on delicate eco-structures of estuarine and coastal wetland ecosystems.

Large temperature changes within a dam reservoir can affect many species of aquatic plankton, invertebrates, mollusks and fish that are extremely sensitive to even mild thermal changes. The water temperature regime of these large reservoirs is altered from its natural state behind the dams. Water channels downstream are also affected as water is released from the dam. Sensitive organisms must either adapt, relocate or die.

An additional concern with the impact of dams on the environment is degraded water quality.  Organics that would normally get washed downstream get built up behind the structure and consume large amounts of oxygen when they decompose. This can result in algal blooms. Rivers that are dammed don’t have the natural transport of sediment that is critical to having a healthy organic riverine channel.

Fish migration depends on a steady flow of a river to guide them to their spawning grounds. Dams can increase the time it takes for migration. While fish ladders and elevators have been installed in some dam structures, getting to them can be devastatingly tedious.

Dams transform the upstream, free-flowing river ecosystem to an artificial, stagnant pond in the reservoir. The changes in temperature, chemical composition, dissolved oxygen levels, and physical properties are not viable to the plants and animals that originally evolved with the river system. Reservoirs host non-native, and invasive species as a result.

Today, many dams that were once at the epicenter of a community’s livelihood that is now old, unsafe or no longer serving their intended purposes and is being removed to restore ecological balance. Trying to weigh the need for developing additional water resources while conserving the environment will continue to impact future generations.

Source:

1. “Environmental Impact of Dams”, International Rivers https://www.internationalrivers.org/environmental-impacts-of-dams 

2. “Problems and Benefits of Building a Dam,” Education Center Online. 2019 http://www.educationcenteronline.org/articles/Engineering-Careers/Problems-and-Benfits-of-Building-a-Dam.html

3. “The Downside of Dams: Is the Environmental Price of Hydroelectric Power Too High?”   Scientific American. https://www.scientificamerican.com/article/how-do-dams-hurt rivers/

4. “How Dams Impact Rivers,” American Whitewater, https://www.americanwhitewater.org/content/Wiki/stewardship:dam_impacts

For Utility Companies, 2019 Could Prove Interesting.

The Swamp Stomp

Volume 19, Issue 3

The demand for electricity has been continuously rising for the past 100 years.  Today, however, the demand is flat, and utilities are having to rethink their growth plans.  The US utility sector was originally built around the idea of perpetual growth in the industry. Now the utility companies are realizing that this may not be the case.

A decrease in energy usage should be good news because it means people are either finding cheaper, more efficient ways to use electricity or they are using less.  Either way, that’s a win-win for the environment. At the same time though, utility companies are slowly watching their revenues dry up.  The original models for the utility industry will have to change with the times. Utilities need to devise new ways to earn revenue, mostly through services, not products, as they have in the past.

The costs involved in the production of renewable energy are getting cheaper every year, and natural gas production is higher than it has ever been. U.S. natural gas exports at the beginning of 2018 were twice the 2017 average. Huge amounts of natural gas are being produced by extraction from shale and other sedimentary rock formations. With the abundance of relatively cheap, clean-burning natural gas, burning coal to produce electricity is no longer a competitive alternative, a big change from the past.

What this means for the future of the utility companies is still not clear. There are two kinds of utility companies, government-owned and Investor-Owned Utility Companies or (IOUs).  The IOUs are not permitted to make money on the actual selling of electricity. They make their money by earning a rate-of-return on power plants and the infrastructure that goes along with it. IOUs are struggling now because their infrastructure investments have dried up, along with their profits and the interests of stakeholders. Future profits are no longer guaranteed.

Utilities are trying to adapt by merging and diversifying into larger conglomerates.   Duke Energy bought Piedmont Natural Gas and has diversified its business by spinning off a company to transport natural gas.  Southern Company is taking a similar strategy, buying wind and solar plants across the country.

The U.S. uses 20% of the total electricity of the world, second only to China, while its per capita consumption is almost triple the consumption of China.  In 2017, U.S. consumption of energy came from many sources.  Over the decade 2004-2014, the largest increases in an electrical generation came from natural gas, wind, and solar. Power generation from coal and petroleum has decreased while other electricity sources have either remained constant or decreased.

These days, consumers are expecting more from their utility companies. They expect easy-to-use online interfaces, data about individual usage, and the option to buy energy from alternative energy sources. Self-production of electrical energy from solar panels is a popular option for many.  Consumers are also becoming much smarter about their energy consumption.  Homes are being equipped with upgrades such as Nest thermostats, solar panels, and LED light bulbs that help keep personal electricity costs under control.

With renewable energy sources becoming more financially competitive and energy-saving technology at our fingertips, utility companies must continue to adapt or face a bleak future.

1. Roberts, David, “After rising for 100 years, electricity demand is flat. Utilities are freaking out,” Vox, February 27, 2018. David Roberts
https://www.vox.com/energy-and-environment/2018/2/27/17052488/electricity-demand-utilities, 

2. Hoium, Travis, “Why Consolidation is the Name of the Game In the Utility Space”. The Motley Fool. June 4, 2016.  https://www.fool.com/investing/2016/06/04/why-consolidation-is-the-name-of-the-game-in-the-u.aspx

3. “Natural Gas Explained,” US Energy Information Administration. December 11, 2018. https://www.eia.gov/energyexplained/index.cfm?page=natural_gas_home

5. “Energy Dominance,” Department of Energy, Year in Review, https://www.energy.gov/department-energy-year-review-2018

Are Monarch Butterflies Becoming Extinct?

The Swamp Stomp

Volume 19, Issue 2

Since 1997, the Xerces Society for Invertebrate Conservation has organized a count of the migrating western m butterfly.  This was initiated when a large decline in the population of the monarch was noticed in that year. Since then, the count has been taken annually at Thanksgiving, along their migratory path to Mexico and California.

“In 1996, migrating monarchs covered 45 acres of forest in central Mexico, each acre holding an estimated 25 million butterflies. In December 2013, the butterflies covered a mere 1.5 acres. In California, the monarch population has dropped by an estimated 80 percent over the past 15 years.”3. Scientists fear the species will become extinct within the next 20 years, according to a study published in 2017 in the journal, Biological Conservation. Chip Taylor, founder and director of Monarch Watch, states, “Monarchs are symbolic of what’s happening on a larger scale, you eliminate monarchs, and you eliminate everything else that shares that habitat.”3.

The decline in Migrating Monarch Butterflies has become more and more alarming. Although the Western Monarchs have migrated through the western US for centuries, a graph of the last 30 years shows an almost exponential rate of decline. The decline has numerous causes: climate change, deforestation/habitat loss, and the agricultural use of pesticides and herbicides.3. These “problems” can all be traced back to the rapid decline of the milkweed plant in their habitat.

Monarch butterflies are fully dependent on milkweed throughout the growing season of the perennial, so a decline in milkweed populations would greatly influence western monarch butterfly populations. If you’re like most, you might not realize that the monarch butterfly cannot survive without the ample presence of milkweed. This perennial plant is the only plant on which the monarch will lay its eggs. Once the larvae hatch, the caterpillar eats the plant. The two organisms exist in a symbiotic relationship because as the milkweed feeds the caterpillar, the butterfly helps pollinate the milkweed.

For many years, since milkweed is not a cash crop, farmers have removed milkweed fields to grow more corn and soy beans. Whole prairies of milkweed have been mowed to the detriment of the milkweed plant. “A large swath of land that is traveled by monarchs runs through the American corn belt, where most of the crops grown are now genetically engineered and heavily doused with herbicides for weed control.”  

Each year, there are four generations of monarch butterflies that can exist. The migrating monarchs begin by laying eggs on their journey north after hibernation. These eggs are the beginning of the next generation for the coming year. The eggs from the first generation of butterflies become the second generation, and so on. The first three generations’ life cycles are consistent. Each generation of a butterfly’s life cycle takes about 2 months to complete.

The fourth generation’s life cycle however, is longer (from 6-8months) and much different. These are the migrating monarch butterflies – eggs laid by the third generation in the September/October time frame.  When these butterflies hatch, they know their southern path to the warmer climate. The monarch is the only non-bird species that migrates over 2,500 miles to a warmer climate.

The monarch butterflies will spend their winter hibernation in Mexico if they live east of the Rocky Mountains.  If they live west of the Rocky Mountains they hibernate in Southern California.  Interestingly, monarch butterflies use the very same trees each year when they migrate. “Most people don’t understand that the monarch, like so many other insects, have a symbiotic relationship with the plant world,” Flanagan said. “They’re connected to the plant world and so when we’re not seeing them, we have to question what’s going on in the plant world.”2.

Those that want to help the monarch butterfly can do so by creating monarch habitats, planting native gardens, and by helping scientists track the species. For additional ways you can help, please see the USFWS “Save the Monarch Butterfly” website.   

1.“Monarch butterfly population in California plummeted 86 percent in 1 year.”  ABC News 7, Chicago, IL, January 12, 2019,  https://abc7chicago.com/pets-animals/monarch-butterfly-population-in-california-plummeted-86-percent-in-1-year/5063396/.

2.Stafford, Audra, “Agency Sees Decline in Migrating Monarch Butterflies,” NBC News, San Diego, CA, January 11, 2019, https://www.nbcsandiego.com/news/local/Western-Monarch-Butterfly-Population-Decline-Encinitas-Butterfly-Farm-504212961.html

3.Dungan, Ron, “Lowly milkweed may be key to monarch recovery,” The Arizona Republic, April 27, 2014. https://www.usatoday.com/story/weather/2014/04/27/monarch-butterflies-milkweed/8226397/


Bats Threatened by White Nose Syndrome

The Swamp Stomp


Volume 19, Issue 1

A fungal disease that has been called “the deadliest disease to hit wildlife in the United States in recorded history” is threatening fifteen species of bats living in North America.(1) The disease is called White Nose Syndrome (WNS), and bats are the only animals that appear to be affected by this pathogen. Six of these 15 affected bat species are now either threatened or endangered with the possibility of becoming extinct altogether.

The actual scientific name for White Nose Syndrome is Pseudogymnoascus destructans, or Pd for short. Pd can infect up to 90% of a bat hibernaculum, which is a place such as a cave, where the bats hibernate over the winter months.  Bats normally hibernate in colonies of hundreds of bats so the infection spreads quickly through a colony and with devastating results. Whole colonies of bats can succumb to the disease in a single winter.  Already, the fungus has killed almost six million bats in North America. 

Pd attacks the bare skin of the bat (primarily the wings and faces) and produces a white fuzz on the surface. Because of this attack to their skin, the bats will periodically and unnaturally awaken while hibernating.  During a normal hibernation period, bats do awaken from time to time and use some small portion of their stored fat. However, the unnatural activity of the disease causes the bat to use much more of the stored fat that is required to survive the hibernating period.  Bats literally die of starvation from the fungus.(1)

The fungus finds its way into the caves of bat hibernacula through many different avenues. Infected bats can leave the fungus behind on the surface of a cave as they travel from cave to cave.  Sometimes cavers, people who study or investigate caves, carry it on their clothing from one bat hibernaculum to the next, and then there are winds and other external sources that may also be factors that introduce the fungus to a cave. Once introduced to a new setting, the fungus attaches itself to the substrate of the cave walls waiting for an unsuspecting bat.

Pd was first discovered in North America in an area near Albany, New York in the year 2006.  No one knows how it reached our continent, but research into the fungus has traced its initial existence to Eurasia many years prior to 2006.  In Eurasia however, the fungus has been around long enough that the bats there have built an immunity to it.  After its initial discovery in our country in 2006, the pathogen has spread across the US into the Midwest and into some portions of Canada.

There is ongoing research into a “cure” for WNS.  Research into the genome of the fungus and others like it, has shown that Pd is missing an enzyme that turns off reparation of DNA after exposure to UV light. This is one avenue that is being pursued by researchers to help eradicate the fungus from hibernacula before the bats have a chance to settle into their cave for the winter months.

Researchers are also studying the habits of some of the hibernating bats that survive WNS.  They have found that Big Brown Bats have developed a strategy of a unified awakening of the whole colony on a nightly basis in response to the WNS and researchers hypothesize that the heat from surrounding bats helps store energy and hence, fat, making survival of the season an option.(1)

The latest research shows that there are bats that have been infected, survived, and then become pregnant. Their immunity will be passed on to their offspring and there will be more and more immunity as these bats survive into the next generation. Natural selection is working for this species of bats, but what about the others? The disease is still new and spreading in North America. It may take many more years before either the fungal pathogen is eradicated or controlled, or multiple native bat species are able to combat the disease through immunity.  Let’s hope that the bats can hold out until this pathogen is no longer a problem.

1. ”White Nose Syndrome. The mystery fungus killing our bats.” Wild Things Sanctuary.org. nd. <www.wildthingssanctuary.org/bats–white-nose-syndtomr.html>