Eroded streambank

A somewhat robust tree grows on the stream bank, but the soil beneath it is exposed and prone to erosion. (Scott Hall)

Several years ago when walking back to my car after a short visit to a park, I noticed that the steep, roughly 70-foot-high hillside bordering the east side of the parking lot was bare dirt except for a dozen or so assorted trees that had managed to secure a foothold on the slope some decades ago.

Additionally, there were tall trees on the hills and banks of the west side and most of the south side of the small parking area. Only the flat ground on the north side and a small section of the hilly south side were free of shade-producing trees — and, not coincidentally, were covered with grasses of one kind or another. The shade trees on the steep hill and elsewhere, as well as a less-than-ideal orientation to the sun, prevented soil-saving ground covers from taking root. And in the dense shade directly under the trees it was nearly impossible. Furthermore, steep slopes tend not to hold leaf litter in place; wind, rainfall and gravity easily send leaves to the hill bottom and then, during sufficiently hard rains, to the nearest storm drain.

When we see signs of soil erosion far away from a stream or river, most of us don’t intuitively recognize it as a source of sediment that will eventually find its way to the Bay, where it clouds the water and deprives underwater grasses of the sunlight they need to thrive and provide dissolved oxygen for other marine life. But, on that particular day at that particular spot, making the connection between the erosion and the Bay's plight was easy — because at the north end of the eroded hill was a storm drain, and the Chesapeake Bay was no more than 200 yards away.

One would think that, of all the adults who lived in the area and visited the park, and of all the adults who own or once owned the homes perched atop those steep hills over the decades, someone would have recognized the soil erosion problem and fixed it because the fix was so simple: Minimize shade and plant ground cover. Securing local approval for disturbing those trees within the buffer of a critical area of the Bay would be easy after bringing officials to the site to see the erosion firsthand.

That no such action had been taken for decades makes it clear to me that we have to do more to educate the public and, in particular, property owners who are losing land (and land value) to erosion but still failing to make the connection.

Streambank with groundcover

Soil on this slope is held in place by a thick mat of grass. (Scott Hall)

Driving the point home for me that day was another steep slope, just a short walk from the parking lot. This one was treeless and had a wide-open exposure, from northeast to northwest. Not surprisingly, it was thickly covered with tall grasses and other ground cover plants.

Here were two similarly steep slopes, just a stone’s throw from each other, yet amazingly dissimilar in terms of protecting the soil from erosion. The operative difference was simple: shade trees on one, no shade trees on the other. The resulting difference was soil protecting lush growth compared with soil exposed to rainfall runoff with sediment ultimately flowing into the Chesapeake Bay.

I realize, of course, that we should think long and hard about removing trees from any natural setting, but we must also recognize that trees alone don’t control erosion in every circumstance — steep slopes being the obvious example. This is especially problematic if the trees in question create deep shade and there is no shade-tolerant ground cover to hold the soil in place.

One can find perfectly demonstrative examples of this problem everywhere, sometimes virtually side by side. Not long after I saw the eroding parking lot slope, I came across a streambank that showed the difference at a single glance (see photos): severe erosion under heavily and low-branched shade trees, and right next to it a dormant but robust growth of tall grass — clearly holding the bank in place.

The difference couldn’t have been more obvious or more easily corrected. On the eroding bank, either reduce the shade by pruning or replace the tree with a more suitable one, or plant groundcover that flourishes year-round in shady and root-embedded soil.

The plight of the Bay and its seemingly insurmountable issues are not the result of immovable forces, nor the result of inexplicable phenomena. Each issue has solutions. We know what those solutions are, and we have to recognize and acknowledge that Bay pollution doesn’t come only from lawbreaking industrial operations or farming or municipal wastewater practices. It comes from all of us, not deliberately, but often because we fail to grasp the obvious.

Taking that time to recognize, to acknowledge, to identify and to appreciate will pay dividends. The Bay and its valuable resources will rebound if we give it a chance. But we have to correct the mistakes that have been made and, because many of those corrections are readily within our reach, the task is not that arduous.

Scott Hall is a lifelong resident of and advocate for the Chesapeake Bay watershed.

The views expressed by opinion columnists are not necessarily those of the Bay Journal.

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