“Don’t stand up while we’re moving. If we come to a sudden stop, we could lose you.” Ray Paterra, visitor services manager of Blackwater National Wildlife Refuge, had just given us lifejackets, earmuffs and a safety briefing for the airboat.

As we took off on the Little Blackwater River and throttled up, Angela Crenshaw, ranger at Harriet Tubman Underground Railroad State Park, and I sat in the front, feeling the abrupt forward impulse of acceleration. I reached around for a handle on the side of the boat, anchoring myself in the seat with one hand and holding on to my hat with the other. We were not going fast by the standards of the airboat, but it felt as if we were racing compared with trolling with an outboard motor.

Armed with various maps and charts, including a section of the local topographical map from 1905, I was looking forward to seeing what people have done to change Blackwater over nearly a 200-year span. We were off first to see three “ditches” or canals dug across the marsh to connect isolated stretches of higher ground to the river.

I was already getting terribly lost. The broad expanse of the “Little” Blackwater at its mouth looks nothing like the old topo map. We moved into an even wider “Lake Blackwater” where the main river once snaked across the marsh.

“So where did the two rivers actually meet?” I asked Bill Giese, retired fire control officer and a refuge volunteer, calling upon his near-half-century of service to Blackwater. “It was way down where you see those islands,” he said. A large piece of marsh around what was Harper’s Pond had vanished.

We moved into the river’s channel — wider than the river a century ago, but narrower than the “lake” we had just left, then cut the engine. Pointing to another stretch of open water, Giese said, “In the 1930s, refuge staff slowed the runoff here a bit to create habitat for waterfowl. You can see what has happened to it.”

He pointed out a branching channel maybe 70 feet across. “Here is Keene’s Ditch. Old timers say that people used this canal to reach their trapping grounds.”

I was eager to follow the ditch to where it comes out, but knew that we could not do this, as the airboat cannot go in reverse. Besides, aerial shots suggest that much of the ditch is washed in almost beyond recognition. I squinted my eyes toward what I reckoned was the end of the ditch. Where were the trees?

From my research, it appears that these ditches were dug in the late 1830s (as demonstrated by county land records as early as 1841 that mention “Cain’s Ditch”). Why would people go to the trouble to dig these ditches if they didn’t stand to bring out a valuable resource such as white oak for shipbuilding or at least cordwood?

Crenshaw looked around at the spongy marsh, seemingly held together only by a few stands of phragmites and water bushes. She asked how they built these canals. Giese  said that “They may have had some sort of dragging dredge, but otherwise they relied on shovels.” Crenshaw looked doubtfully at the mire that is now the marsh. “Of course, the marsh was higher then,” Giese quickly added. “Otherwise, the mud would have slid right back into the ditch.”

I offered my two cents’ worth of history. “We have to rely on other accounts to help tell the story here. The canals in Dismal Swamp in Virginia were dug by enslaved people, who were hired out or able to hire themselves out, a set sum going to the so-called owners and maybe some extra money for the hands to keep for themselves. A story from Quantico in Wicomico County noted that it took seven workers seven years to dig a three-mile canal that was 8 feet deep and 10 feet wide at the bottom.”

The Maryland General Assembly in 1825 used “boilerplate” language for a ditch proposed by John Jaques across Hurley’s Neck to link the Nanticoke and Transquaking rivers south of Vienna—a few miles to the east of here. The authorization states that Jaques “shall cause the dirt coming out of the proposed canal in excavating the same to be thrown equally on both banks or sides of said canal so as to prevent the water from rising and overflowing the marshes and lands through which the said canal shall pass.”

I tried to square the history with what I saw. Ditch banks on both sides to stop overflow? A 10-foot-wide canal? I am looking at Simon’s Ditch, our next stop which—like Keene’s Ditch and our upcoming stop at Booze Ditch—was easily more than six times that width and nearly without any high ground to support water bushes.

We moved up the ditch, where the wider channel maintains the same route to a pond. I looked across a stretch of marsh to see two islands in the marsh that still support trees. The ditch seems to have ended in marshland halfway between these islands. Yet, just ahead, I saw a familiar spike or dead tree along the marsh road. This stretch surely had a healthy stand of trees at one time that connected the two islands. A few spikes and stumps are all that are left, mostly hidden in the marsh grass.

We reached Booze Ditch (also known as Cole’s Creek) just upriver from Shorter’s Wharf and soon saw the channel widen into The Broads, a sort of elongated lake that widens the channel, much like what is found at the remnants of Dunnock’s Canal on the way to Hooper’s Island. We reached Barnes’ Landing, another point where timber lands would have met a canal, seeing spikes, stumps and stands of dead trees across the edge of the marsh, again separating the ditch from the nearest surviving woods.

Giese then guided us through a series of channels and washouts from Lake Blackwater up Meekins Creek — seemingly more a bay — to see the former 950-acre tract of Walter A. Gibbs, a retired railroad employee from Pennsylvania who started a profitable business inventing and selling traps for muskrats and other animals. Giese told us about the mud machine designed by Gibbs that trenched off sections of marsh that were then lined with board barriers where live-trapped muskrats would be held until they were shipped for sale to fur farmers.

“He had a sort of guardhouse above the marsh, where a worker would watch for a flag that showed that a live trap had sprung during the day. At night, the sprung trap would set off a carbide light. He sold his muskrat [pelts] across the country and even to Europe.”

Giese located one of the old enclosures in a flooded extension of the creek. It is hard to imagine that this waterlogged marsh could have impounded (let alone, supported) muskrats — even if the habitat had been “improved” with drainage channels and ditch banks.

Meanwhile, another neighboring trapping operation, Delmarvia Fur Farms, failed — either the result of the waterlogging of much of the prime muskrat habitat or as a result of the declining markets of the Depression. The property was sold to the federal government, creating Blackwater Migratory Bird Refuge.

As the airboat skidded and bumped over submerged stumps, I asked Giese how an area of healthy woods could in such a short time sink into a submerged bed of stumps rather than turn into high marsh. “When the trees die like this,” he explained, “the roots begin to decay and remove the support for the land. The land sinks, and the stumps and spikes sink under the water.” Paterra, the refuge’s visitor service’s manager, added, “I’m not really sure whether there is any high marsh left on the refuge, except maybe the new acquisition along Smithville Road. With much of this low marsh today, it seems as if only the phragmites is holding the land in place.”

“I remember these woods when I was first working at Blackwater in the 1970s,” Giese recalled, as we made our way around Sprigg’s Island. Once a peninsula in the closing decades of the 19th century, Sprigg’s attachment to the mainland had washed out to a mudflat occasionally seen in low tide. “This has all happened so fast and seems to be picking up speed,” he said.

Crossing Lake Blackwater at a seemingly fast clip to return to the dock on the Little Blackwater, I thought about another kind of acceleration that outpaces even our scudding along in the airboat. J. R. McNeill and Peter Engelke called their history of the environment since 1945 The Great Acceleration. Using a term first employed in 2005, the authors note that since the middle of the 20th century, the global population has nearly trebled, the number of the world’s motor vehicles has increased from 40 million to 850 million, and 75 percent of human-caused carbon loading has taken place.

These influences have led to what the authors call “certainly the most anomalous and unrepresentative period in the 200,000-year-long history of relations between our species and the biosphere.” The acceleration certainly can be seen in the change on the Blackwater between the topo maps showing the first 40 years of the period described by McNeill and Engelke. The 1943 map still shows the original river channel, although much of the bank has been eroded to only a few slender and fraying islands along the banks. The 1982 map shows a fully fledged Lake Blackwater forming where it once met an equally swelling Little Blackwater.

As I leave the dock and think about the ditches we visited on our boat trip, I reflected about the impact they might have had on the Blackwater basin.

Did those ditches, along with the cutting down of timber on the edge of the Blackwater marshes, result in erosion and silting? Did these ditches in places sink and/or wash out to create the elongated ponds of the broads?
Did a few ditches we did not visit, those dug to create a shortcut to bypass an oxbow of the river — such as Job’s Ditch down river from Shorter’s Wharf or Raymond Ditch through the oxbow where Meekins Creek once met the Blackwater — help to drown the marsh that was bypassed?

Certainly, the ditches built during the 19th century — notably Stewart’s Canal and the Coursey Creek Canal, both of which connected the upper Blackwater to the Little Choptank River — helped the transformation of the Blackwater basin by opening new stretches to erosion and even another set of tides.

Yet, other forces, ranging from severe storms to sea level rise, were also at work, accentuating tidal forces from the Little Choptank and Fishing Bay. Whether caused by major storms or the cycles of the seasons, each tide washed away a little more marsh, flooded a few more trees, and progressively eroded the banks of the ditches and rivers.

Leaving the refuge, I drove across the marsh road toward Shorter’s Wharf. The spike at what appeared to be the end of Simon’s Ditch again seems to be the last sentinel of a stand of trees that once must have lined half the distance of the road across the marsh, built more than a century ago to replace the ditches that were their only original connections between this high ground and the rest of the county.

As I left to cross the low marshes on the southern section of the road that eventually parallels the Blackwater in its course toward Shorter’s, I saw the lowest points of the road with the last puddles of the retreating water from the day’s tide. I did not have to slow down to cross the ribbons of tidal water recently streaming across the road this afternoon.

As I gained speed and reflected on my accelerated visit to Lake Blackwater, I know that tomorrow’s tide will rise a little higher and linger a bit longer.