Waterways are not
sewers
How many of us toss things in the water, just
because it is the easiest thing to do? Factually, nothing we throw into the
water is helpful to our waterways, and most things are harmful. Additionally,
throwing anything in the water is a violation of Virginia
law.
The Code of Virginia (Section 62.1 –194) specifies
that “…it shall be unlawful for any person to cast, throw or dump any garbage,
refuse, dead animal, trash, carton, can, bottle, container, box, lumber, timber
or like material, or other solid waste, except fish (bait) or crab bait in any
form, into any of the waters of the Commonwealth.”
Everybody seems to throw their rockfish carcasses
in the water, possibly in hopes the neighbors will notice what great fishermen
they are. The excuse (which also applies to bags of lawn grass, dead squirrels,
chicken skin, and hard crab debris – I have actually observed all these things)
usually takes one of two forms.
“I’m just feeding the crabs.” In summer (but not
winter) the crabs will, indeed, consume some, but not all, the fish carcass.
Most of it will rot (undergo microbial decomposition), consuming dissolved
oxygen, and the nutrients nitrate and phosphate will be returned to the water to
foster the growth of suspended algae. The algae grow very rapidly and cloud the
water. The cloudy water from the rapid algal growth prevents light penetration
and the growth of sea-grass, or SAV (Submerged Aquatic Vegetation) that provides
food and sanctuary for many marine organisms. Because there aren’t enough
animals to eat all the suspended algae, and because the algae are short-lived,
many of them die and then settle to the bottom. On the bottom, microbes
decompose the algae, consuming dissolved oxygen in the water and stressing
animal life.
Things can get really bad, especially in summer
when the water is warm. The solubility of gasses like oxygen decreases with
increasing temperature, so the warm water can only contain small amounts of
oxygen. If it is very still, atmospheric oxygen is not mixed into the water by
the wind. In the worst case, the water becomes stratified, or layered, with less
dense (fresher or warmer) water at the surface and denser water beneath, out of
contact with the atmosphere but in contact with the organic-rich bottom mud.
Under these circumstances, oxygen levels can fall low enough to cause fish
kills. If you want a vivid picture of what happens in the bottom of our creeks,
jam a stick in the water, pull it up along with a bit of the muddy bottom, and
take a whiff!
The crabs’ problem is not lack of food – there is
plenty of food naturally present in the water. The crab’s problem is not enough
habitat like SAV and marsh grass beds, and the killing of egg-bearing females
(sponge crabs). Think of it this way. Is all the nitrogen and phosphorous in
that rockfish carcass eaten by crabs, which are then caught and removed from the
water? No. Most of the nitrogen and phosphorous is added to the water column by
the rotting carcass. More nitrogen and phosphorous is, of course, continually
being added to the creek from your drain-field, which is merely processing the
delicious rockfish (and everything else) you ate for
dinner.
“I’m just returning it to the sea” is the other
common rationalization for people who throw fish or crab debris into the water.
True, you are returning it to the sea, but not to where it came from. The
organism probably came from the open Bay, and throwing it into a small creek
overloads the ability of the small body of water to process it. Disposing of the
debris in a landfill or compost pile removes the nutrients from the water. The
fish/crab debris didn’t come from the creek, so don’t add it to the creek. Once
the organic material is out of the water, don’t put it back
in.
Grass clippings are an especially onerous form of
waterway pollution. Every gardener knows that grass clippings added to a compost
pile provide nitrogen. The rapid decomposition of the grass raises the
temperature in the compost pile, killing undesirable seeds and microbes. Grass
clippings also make great fodder for herbivores, because they are so nutrient
rich. Throwing (or blowing) grass clippings into the water is just like throwing
fertilizer into the water. Composting is an easy and useful
alternative.
If you are in the habit of using the creek as a
personal garbage pit, remember that you are breaking the law every time you do
so. You are also consciously contributing to poor water quality. As you head for
the creek with your trash, ask yourself: If I lived in downtown Heathsville
would I carry this out and throw it in the gutter? The waterways will be better
off if all of us treat them as treasures, not as convenient
sewers.