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Shoreline Erosion

         Shoreline erosion is evident, even in the smallest creeks, anywhere in the County where there are steep banks adjacent to waterways. Trees toppled into the water, or leaning toward it as their roots are bared provide unequivocal evidence of the fact that our shorelines are eroding. If more evidence were needed, one has only to look at the large number of permits that are requested each month by waterfront property owners to control erosion with bulkheads, rip-rap or other means. The sediment eroded from the shoreline is dispersed throughout the creeks and rivers and is one reason why so many oyster beds have been smothered. There are three reasons erosion is rampant.

            The first two reasons are coupled. Sea level is rising relative to the land surface. Not only is sea level rising in a absolute sense, but Virginia's Coastal Plain is subsiding (sinking). The two effects are about equal, about 2 millimeters each year, and add up to a net apparent rise in sea level of 4 millimeters each year, or about a foot in a person’s lifetime.

            Sea level is rising globally as the result of climatic warming. The evidence that the climate is warming is now overwhelming and is no longer questioned by many scientists. Climatic warming causes sea level to rise by melting continental ice, mostly on Greenland and Antarctica, and by warming the water in the ocean, which then expands. In addition to an overwhelming number of actual temperature measurements, climatic warming is also documented by observations like the retreat of glaciers and ice shelves, and the pole-ward expansion of disease-carrying insects. Still somewhat controversial is the cause of the warming. The majority of scientists have concluded that it is primarily, or at least in large part, caused by anthropogenic "greenhouse gasses". We are adding carbon dioxide (CO2), methane (CH4), chlorofluorocarbons (CFCs) and nitrous oxide (N2O) to the atmosphere, primarily (except for CFCs) as the result of the burning of fossil fuels (oil, natural gas, and coal). Sea level will almost certainly continue to rise until Earth’s fossil fuel supply is exhausted within the next 200 years.

            Our land is also subsiding. Earth's crust is in constant motion. Horizontal motion, such as occurs along features like the San Andreas Fault system in California, is periodically obvious. Slow vertical movements are usually less violent and harder to document. Briefly, about 10,000 years ago at the glacial maximum, ice extended as far south as northern Pennsylvania and New Jersey. The weight of this ice depressed the land surface beneath it, and bulged up the land near the southern edge of the ice, where we are located. Once the ice melted, the land beneath it rebounded, and the "bulge" began to collapse, manifesting itself in the land subsidence we observe today. There is obviously nothing we can do about this phenomenon, whereas there is something we can do about global warming!  A small, but possibly increasing, cause of land subsidence is the steady decline in water levels in wells tapping our deep aquifers. Water withdrawal allows the aquifers to compact, with consequent subsidence of the land surface.

            The third reason for shoreline erosion is also our fault. Boat and personal watercraft wakes create waves that undermine the creek banks, especially in the smaller creeks not normally subject to such large waves. The solution is simple: Always Proceed at No Wake Speed in small creeks, and keep your speed down in the rivers, especially if you own a large powerboat. Never make waves larger than Nature makes.

            Waterfront property owners bear a special burden in combating erosion as they strive to protect their property. Bulkheads and rip-rap are expensive, effective, and artificial. Alternatives, including "coconut logs" and transplanted grasses, are also being tried, and it remains to be proven how effective they will be if predictions are correct that sea level will rise at least a foot (maybe more!) by the end of the 21st century. If you need help, contact  SEAS, and the Shoreline Erosion Advisory Service will be glad to help you at www.dcr.state.va.us/sw/seas.htm or (804) 443-3803.

Waterfront Property Stewardship I - Nutrification

            Waterfront property owners are blessed with a unique environment in which to live. Along with that blessing comes the responsibility to treat local waterways so as to preserve and enhance them for all citizens of the County and State, even in the smallest creeks. Individual property ownership ends at the shoreline. None of us own the water adjacent to our property. There are many things that property owners (and others) can do to improve our waterways. Pogo was right. “We have met the enemy and he is us”. We can’t blame the deteriorated condition of our local waterways on “those urban folks”. We ourselves are to blame.

First and foremost, never throw anything into the water. If any kind of organic material is thrown in the water (kitchen or yard waste like grass clippings, fish carcasses, crab shells, etc.), most of the organic material will ultimately be decomposed by bacteria. The decomposition of organic material consumes dissolved oxygen, which animals need. Bacterial decomposition releases the nutrients (nitrogen and phosphorus) from the organic material. These nutrients fertilize algae, which grow in the water column and cloud the water, limiting the ability of submerged plants to grow. Submerged plants (Sub-Aquatic Vegetation, or SAV) retard erosion and provide habitat for juvenile fish and crabs. By destroying SAV throughout the Bay, we have destroyed about 90% of a major Bay habitat.

"Over-fertilization" of the Chesapeake Bay has been identified as the single biggest threat to the health of the Bay. Local additions of organic material directly to the water, along with effluent from septic systems and agricultural lands, which enter each and every waterway by normal groundwater discharge, are all forms of "non-point source pollution". These kinds of “nutrification” are of great concern as we seek to voluntarily de-list Chesapeake Bay from EPA's "impaired waters" list by 2010. Many people justify throwing organic debris into the creeks as “feeding the crabs”. But the crabs’ problem is not lack of food, it is lack of habitat like grass beds to grow up in. We need to improve water clarity by reducing the nutrients added to our local waterways so that grass beds can be re-established.

If other kinds of waste are added to the water (oil, batteries, electrical equipment, soap from washing vehicles, etc.), toxic substances can be released which are detrimental to both plants and animals. Waterways are not sewers, although treating waterways like landfills was a common practice in the past. Natural environments are remarkably resilient, and a few families disposing of their wastes in the creeks probably didn't have much of an impact a century ago. But there now are simply too many people generating too much trash for this practice to continue.

            We all, especially waterfront property owners, should minimize the use of fertilizers and pesticides. These materials should be used exceedingly sparingly, and always according to the instructions. It is a good idea not to use any chemicals (fertilizers, weed killers, etc.) in the Resource Protection Area (RPA)  within 100 feet of the waterway.

            Open lawn should be avoided on property adjacent to waterways. Instead, trees and low shrubs should be planted along the shoreline, and especially between the drain-field (never over it!) and the waterway. The deep roots of trees and shrubs help hold the soil and consume some of the nutrients in the groundwater before the dissolved nitrate and phosphate can be discharged into the waterway by normal groundwater flow. “Bayscaping” is more environmentally sound and easier to maintain than open lawn. Big shade trees “frame” the view of the water and, if properly placed, also provide shade which reduces summer cooling bills.

            Waterfront property owners must also be especially vigilant to ensure that their septic system is working properly. The septic tank should not be full of sludge. If it is, anaerobic decomposition cannot take place efficiently and the absorption field can become clogged. Harsh chemicals (bleach, ammonia, solvents, etc,) should never be poured down the drain or the microbes that make a septic system function properly can be killed. Minimizing the amounts of both solids and water that go down the drain reduces the nutrient output to the groundwater and increases the life span of the septic system.

            The next “Stewardship Tip” will discuss other actions that waterfront property owners can take to improve our waterways.

Waterfront Property Stewardship II

            In addition to the cardinal rule of never throwing anything into the water, there are many other actions that waterfront property owners (and others) can take which will improve our local waterways:

Keep the shoreline clean. Remove all litter, as well as excess leaves and branches.

If there is a marsh adjacent to your property, do a bit of “marsh gardening”. Your marsh needs care just like your shrubs and flowers. Remove logs and large branches to open up space for the grass to grow. Most important, prune all overhanging limbs and brush to allow light to penetrate. Healthy marshes require full sunlight in order to perform several extremely important roles. Marshes are the most productive ecosystems on the planet and provide food and habitat for many juvenile organisms of both commercial and recreational value. The roots (called rhizomes) of marsh grasses also retard erosion. Marshes have been called "nature's kidneys". In addition to trapping sediment, marshes also literally destroy nitrate. The bacteria which convert dissolved nitrate into nitrogen gas (a process called denitrification) require a unique set of circumstances. Denitrifying bacteria can only function under anoxic (or no-oxygen) conditions such as exist in the black organic-rich mud in the marsh.  Here the nitrate from excess fertilization and from our septic systems enters the marsh by both runoff and groundwater discharge, and is converted into harmless nitrogen gas before the nitrate can enter the water and promote the growth of suspended algae.

Encourage marine grass growth along the margins of creeks by pruning limbs that overhang the water. You accomplish three useful things by this simple act. First and foremost, with the limbs gone, more light can penetrate so the marine grasses won’t be shaded out. Second, the reduced weight of limbs toward the water will slow the tipping of the tree. And finally, you will reduce the number of leaves, needles and branches that enter the water. Less organic matter in the water means less oxygen will be consumed as bacteria decompose it, and fewer nutrients will be released to the water by the bacterial decomposition process.

            Expand marine grass growth along your shoreline by transplanting grasses in May. Single plants or small clumps of plants with adequate root mass can be taken from lush marshes (with permission, of course), or they can be bought (contact SEAS, the Shoreline Erosion Advisory Service at (804) 443-3803 or www.dcr.state.va.us/sw/seas.htm for the names of suppliers). The common “smooth cordgrass”, Spartina alterniflora, should be planted in intertidal zones on about 2 foot-centers. A pinch of a slow-release fertilizer will get the plants off to a good start.

            Prevent shoreline erosion and don't allow soil and dirt to run into the water off your property. Sea level is rising about 4 millimeters (3/16 inch) each year in Northumberland County (2 inches each decade, or over a foot in your lifetime). Rising sea level, along with boat wakes, is the reason why so many trees are toppling into the water and the edges of our marshes are eroding. Sediment from the eroded creek margins causes the creeks to shoal up, and smothers bottom dwelling organisms like oysters. SEAS will be glad to give you free advice about how to best combat erosion on your property.

            Always proceed at No-Wake speed if you are boating in restricted waterways so as to minimize erosion. Never make waves larger than Nature makes. Open your throttle(s) in the open Bay, not in the creeks and narrow rivers. Owners of personal watercraft should enter small creeks at idle speed only. Wakes from fast-moving (and noisy!) watercraft create waves much larger than are generated during the largest storms, and are major causes of both marsh and bank erosion in our small creeks.

            Grow oysters in floats. Oysters feed by filtering small organisms out of the water, which cleanses it. If the water can be made clearer, light can penetrate to the bottom of the waterway and sub-aquatic vegetation (SAV) can establish itself. Like intertidal marsh grasses, SAV increases the oxygen content of the water, provides habitat for organisms of commercial and recreational value, and retards erosion. Many local creeks once had plenty of oysters, and maybe they will come back if: (1) more breed stock is present in floats, especially if the breed stock is resistant to the two diseases which kill adult oysters, (2) undisturbed substrate is available (or made available - thick piles of oyster shell over old “reefs” are best), (3) bank erosion is curtailed, and (4) nutrification of the creeks is reduced. To get involved in "oyster gardening" contact Don Beard at (804) 438-6563 or donbeard@rivnet.net.  

Chesapeake Bay is Impaired!

          It’s true. Since 1999, Chesapeake Bay has been on EPA’s “impaired waters” list. What does this mean? Stated simply, if we do not voluntarily reduce the input of nitrate and phosphate into the Bay and its tributaries by 2010, we face Federal mandates.

          Why should the Northern Neck be concerned? We only contribute a very small fraction, about 5%, of the nutrients that enter the Bay system. There are several reasons why we need to take action, rather than pointing our fingers at “those who are mostly at fault”. First, we, ourselves, ARE at fault, and it is primarily our actions that affect our local waterways. There are many potential benefits to our County if our local waterways can be made clearer. Our commercial and recreational fisheries and bird life will improve. More visitors will be attracted to our beautiful County.

The nitrate that we release to our local waterways promotes the rapid growth of suspended algae, which cloud the water and inhibit the growth of Submerged Aquatic Vegetation (SAV). SAV provides habitat for many organisms of commercial and recreational value, as well as adding oxygen to the water and retarding erosion.

            What can we do voluntarily? First we need to know the sources of the nitrate and phosphate for targeting. There are four sub-equal sources.

1) Wind-borne material (aerosols) - High temperature combustion in engines and power plants converts nitrogen gas into nitrous oxides (NO_x) and ultimately into nitrate, which is washed out of the atmosphere by rain. Some forms of NO_x along with carbon dioxide are “greenhouse gasses” which contribute to global warming and sea level rise.

2) Wastewater treatment plants - These "point sources", most associated with urbanized areas (including Reedville), release nitrate and phosphate to the rivers emptying into the Bay or to the Bay itself.

            3) Agricultural operations - Fertilizer not utilized by crops enters our shallow groundwater, which contains about 5 mg/l (ppm) nitrate on average. Less than 1 ppm nitrate is “normal”. Shallow groundwater flows toward and into the nearest waterway at rates of about 100 meters/year.

4) Most citizens - Septic systems discharge most of the nitrogen and phosphorus that we flush down the drain to the groundwater, as is also true if we use excess fertilizer. With so many homes clustered along the water, waterfront property owners are prime sources of this kind of "non-point source" nutrification.

          What can we do to reduce the release of nitrate and phosphate to the environment? Here is a brief list:

Conserve energy. Aside from reducing the emission of greenhouse gasses we need to conserve fossil fuels because they are a finite resource. The US has already pumped and burned more than half its oil. Most of Earth’s remaining oil is in the Middle East (it’s not ours). Fossil fuels will begin to run out in this century – first oil, then gas, then coal. The “energy crisis” is real and looms larger each day, especially in the face of the ever-expanding human population.

Start planning for new wastewater facilities and upgrading those that already exist to include "tertiary" treatment such as Biological Nitrogen Removal (BNR).

Everyone, farmers included, should employ Best Management Practices (BMPs). Citizens should encourage governmental support for this important agricultural program. Agriculture is important to our County and we should all do as much as possible to encourage its responsible practice.

Maintain septic systems wisely and have the tank pumped every 5 years. Minimize both the solids and water that go down the drain. Don't use garbage grinders/disposals.

Minimize the use of fertilizer (and pesticides, herbicides, etc.) and never use more than is recommended. Plants can only use so much N and P, and the rest is just pollution. Be especially careful within the Resource Protection Area (RPA), or within 100 feet of the water.

Never throw anything in the water. Nature provides abundant food for our marine life. Nothing we add to the water improves the health of our waterways.

          If we fail to meet EPA’s standards by 2010, what will be the consequences? We can only guess, but mandating the list of voluntary actions just described is a pretty good start. In order to “cost account” the nutrients, TMDLs (Total Maximum Daily Loads) will likely be established for each of our waterways. Suppose you were told “You must reduce the daily output of nitrate and phosphate from your property by 20%. You must submit a detailed “budget” clearly and quantitatively stating how you intend to do this, or else…..”. TMDLs will certainly not be required of each of us, but we all live in the watershed of one of our local waterways. Thus we all contribute to the nutrient load of that waterway.

Let’s not wait for the pain that will certainly accompany Federal mandates. The goal is clear. Let’s all pitch in now, and voluntarily make the necessary changes in our life style to benefit the Bay all citizens of our County.

Oysters I ­ The Current Situation

 Blue crabs and oysters are probably the two marine organisms for which
the Chesapeake Bay is most famous. Oysters are filter feeders. They pump
water over their gills and extract both oxygen and small particles of
organic material, including algae, on which they feed. In 1989, R. Newell
estimated that at the end of the 19th century, oysters could filter the
entire volume of water in the Chesapeake Bay in four or five days. Today it
takes more than a year. Between 1870 and 1890, Maryland harvested more than
10 million bushels of oysters each year. The harvest today is less than one
percent of that figure. What happened?
    The cause of the decline in natural ecosystems worldwide has a single
cause ­ the explosive growth of the human population since the industrial
(agricultural, medical) revolution. We humans, collectively, are
responsible. In the case of oysters, it is generally accepted that there are
several specific factors that have contributed to the decline in harvests.
Firstly, oysters are susceptible to two diseases, "MSX" and "Dermo".
Although still somewhat controversial, many scientists believe that both
diseases are caused by "exotic organisms" that were introduced into the Bay,
probably by the discharge of ballast water from ships that filled their
ballast tanks in the European Mediterranean Sea and/or Asia.
There is no question that over-harvesting oysters, and especially the method
of harvesting, is also responsible for the decline in harvests. Just as is
true of ecosystems worldwide, habitat destruction is a paramount problem.
Healthy oyster reefs build up from the bottom toward the water surface. In
this way many oysters can grow above the mud, in relatively clear water, and
juveniles can settle and begin to mature safely in the interstices between
the larger shells. Healthy oyster reefs provide habitat for many other kinds
of organisms of commercial and recreational value, and were once extensive
enough to be serious hazards to navigation. No more! Repeated dredging and
tonging have flattened the mounded reefs so that young oysters no longer
have a stable substrate to which they can attach. The flattened layer of
shells makes it difficult for oysters to stay above the mud and provides
little protection from predators.
Selectively harvesting the largest oysters is also a problem because it
removes the most efficient spawners from the population. Worse, by
harvesting the largest (and oldest) individuals (and killing all the baby
oysters attached to their shells) we remove individuals which may have
developed a resistance to disease. By selectively harvesting the older,
potentially disease-resistant individuals, we are stopping evolution in its
tracks and preventing the species from naturally evolving toward resistance
to the diseases.
    The most recent attempt to improve the oyster harvest is to construct
large reefs and to declare them as sanctuaries. The idea is to build piles
of oyster shells in places where natural reefs once existed, based on
historical records, and then declare them "off-limits" for harvesting. In
this way, it is hoped that individuals which survive the diseases will spawn
and transfer resistance to their offspring. The abundant spat from the
artificial reef will also colonize substrate outside the sanctuary area and,
over time, increase the commercial harvest. This scheme has the added
advantage of increasing the number of oysters that can filter algae from the
water. If oyster populations increase, then water clarity will improve,
submerged aquatic vegetation (SAV) can become more common, and the entire
Bay ecosystem will improve.
    In another attempt to improve the commercial oyster harvest, large
individuals which may have developed disease resistance are spawned in the
laboratory. Unlike many aquatic organisms, oysters are relatively easy to
culture. The abundant spat can then be used as "seed" on artificial reefs,
or made available to individuals who wish to culture oysters for their own
consumption and, at the same time, filter the water in their creeks or
rivers. Keeping track of the mortality of each strain, as is being done at
VIMS, will identify which strains survive the best. More information about
the selective breeding programs, the artificial reef program, and how you
can help, can be found at the VIMS web site, www.vims.edu, or at
www.oystergardener.org, the Tidewater Oyster Growers Association.
    The next article will discuss the expanding practice of "oyster
gardening", and provide information about how waterfront property owners or
individuals with access to the water can participate. If you missed a NAPS
Stewardship tip, they can be found, along with links to other sources of
information at the NAPS web site, www.geocities.com/northumberlandnaps.

Oysters II – Oyster Gardening

          Shellfish have been cultured by humankind for millennia. Recently, Virginians and Marylanders have discovered how easy it is to “garden” oysters.

          Basically, oysters require moving water of appropriate salinity and adequate oxygen content, and food they can filter from the water. Our local waterways provide these requirements in abundance, and many local waterways once supported flourishing reefs. Over the last decade many schemes to grow oysters artificially have evolved, but they all follow the rule “Moving water, up out of the mud, and room to grow”. The most common scheme is to employ a “Taylor Float” of sturdy plastic mesh hanging from a PVC pipe frame for flotation. Flotation can also be provided by plastic bottles or a sheet of styrofoam insulation. Some type of top is necessary to keep birds, crabs and otters out, and to provide shade so algae are discouraged from fouling the oysters. It is also possible to grow oysters in cages on the bottom elevated above the mud. Tending the oysters at least monthly, to remove leaves, pine needles, crabs, etc., to stir them up and separate shells that have grown together, and to remove mud that may have accumulated, is also advised.

          Two oyster diseases, “MSX” and “Dermo” kill adult oysters (they do not affect humans), so initiating a “garden” in the fall is the best strategy. In this way the spat can grow for about 20 months before they become susceptible to disease during their second summer. Each fall workshops are held where floats are constructed and spat are distributed, and attendance is a good way to get started. This year they are being held on September 15 at the Reedville Museum (453-5950) and on October 13 at Port Kinsale marina (472-2044).

          There are several good reasons to grow oysters even if you don’t like to eat them. First, and foremost, oysters filter algae out of the water, clarifying it. If our waterways can be made clearer, submerged aquatic vegetation (SAV) can become re-established and provide important habitat for many organisms like crabs and fish of commercial and recreational importance. Second, the oysters can be used as “seed” on artificial reef sanctuaries which have been and continue to be constructed. Oyster gardeners can obtain free spat if they want to participate in this program, which is sponsored by the Chesapeake Bay Foundation. Oyster gardeners can also enroll in a program at the Virginia Institute of Marine Science to track the mortality of different strains of oysters which are being developed, some of which, hopefully, will prove to be disease-resistant. And finally, oyster gardens are an important source of spat which will encourage the re-growth of local reefs.

          There are several words of warning, however. A (free) permit is required so that the State can track the magnitude of the effort and ensure that no hazard to navigation exists. Also, it is quite common for our waterways to be restricted for the harvesting of all kinds of shellfish, whether or not they are grown artificially. The restriction exists because of high levels of fecal coliform bacteria, especially toward the headwaters of our creeks and rivers. Virginia is extremely strict about coliform bacterial levels to ensure that live oysters eaten locally or exported to out-of-state do not cause illness. The source of the bacterial contamination is not known with certainty, although wildlife (especially raccoons), water birds and pets are implicated, as well as privies and non-functional septic systems. The restrictions do not apply to fish or crabs, and should not discourage people from starting oyster gardens because it is possible to move the edible oysters to unrestricted waters so they can purify themselves. But growing oysters just for “seed” is good for the creeks, fun, and a great learning experience for children and grandchildren (as well as everyone else). You can find the location of restricted waters at the Shellfish Sanitation Division of the Virginia Department of Health in White Stone (804) 435-1095.

For more information about oyster gardening, contact Don Beard, who coordinates the Northern Neck Oyster Gardeners Association, at 172 Tilden Lane, Weems VA 22576, (804) 438-6563, or donbeard@rivnet.net. The VIMS web page at www.vims.edu/abc/green,  the Tidewater Oyster Gardeners Association at www.oystergardener.org and the Chesapeake Bay Foundation at www.cbf.org are all good sources of additional information.