It was a routine occurrence in many communities along tributaries of the lower Susquehanna River during the most recent two months. The rain falls like it’s never going to stop—inches an hour. Soon there is flash flooding along creeks and streams. Roads are quickly inundated. Inevitably, there are motorists caught in the rising waters and emergency crews are summoned to retrieve the victims. When the action settles, sets of saw horses are brought to the scene to barricade the road until waters recede. At certain flood-prone locations, these events are repeated time and again. The police, fire, and Emergency Medical Services crews seem to visit them during every torrential storm—rain, rescue, rinse, and repeat.
We treat our local streams and creeks like open sewers. Think about it. We don’t want rainwater accumulating on our properties. We pipe it away and grade the field, lawn, and pavement to roll it into the neighbor’s lot or into the street—or directly into the waterway. It drops upon us as pure water and we instantly pollute it. It’s a method of diluting all the junk we’ve spread out in its path since the last time it rained. A thunderstorm is the big flush. We don’t seem too concerned about the litter, fertilizer, pesticides, motor fluids, and other consumer waste it takes along with it. Out of sight, out of mind.
Failure to retain and infiltrate stormwater to recharge aquifers can later result in well failures and reduced base flow in streams. (Conoy Creek’s dry streambed in June, 2007)
Perhaps our lack of respect for streams and creeks is the source of our complete ignorance of the function of floodplains.
Floodplains are formed over time as hydraulic forces erode bedrock and soils surrounding a stream to create adequate space to pass flood waters. As floodplains mature they become large enough to reduce flood water velocity and erosion energy. They then function to retain, infiltrate, and evaporate the surplus water from flood events. Microorganisms, plants, and other life forms found in floodplain wetlands, forests, and grasslands purify the water and break down naturally-occurring organic matter. Floodplains are the shock-absorber between us and our waterways. And they’re our largest water treatment facilities.
Why is it then, that whenever a floodplain floods, we seem motivated to do something to fix this error of nature? Man can’t help himself. He has a compulsion to fill the floodplain with any contrivance he can come up with. We dump, pile, fill, pave, pour, form, and build, then build some more. At some point, someone notices a stream in the midst of our new creation. Now it’s polluted and whenever it storms, the darn thing floods into our stuff—worse than ever before. So the project is crowned by another round of dumping, forming, pouring, and building to channelize the stream. Done! Now let’s move all our stuff into our new habitable space.
Natural Floodplain- Over a period of hundreds or thousands of years, the stream (dark blue) has established a natural floodplain including wetlands and forest. In this example, buildings and infrastructure are located outside the zone inundated by high water (light blue) allowing the floodplain to function as an effective water-absorbing buffer.Impaired Floodplain- Here the natural floodplain has been filled for building (left) and paved for recreation area parking (right). The stream has been channelized. Flood water (light blue) displaced by these alterations is likely to inundate areas not previously impacted by similar events. Additionally, the interference with natural flow will create new erosion points that could seriously damage older infrastructure and properties.
The majority of the towns in the lower Susquehanna valley with streams passing through them have impaired floodplains. In many, the older sections of the town are built on filled floodplain. Some new subdivisions highlight streamside lawns as a sales feature—plenty of room for stockpiling your accoutrements of suburban life. And yes, some new homes are still being built in floodplains.
When high water comes, it drags tons of debris with it. The limbs, leaves, twigs, and trees are broken down by natural processes over time. Nature has mechanisms to quickly cope with these organics. Man’s consumer rubbish is another matter. As the plant material decays, the embedded man-made items, particularly metals, treated lumber, plastics, Styrofoam, and glass, become more evident as an ever-accumulating “garbage soil” in the natural floodplains downstream of these impaired areas. With each storm, some of this mess floats away again to move ever closer to Chesapeake Bay and the Atlantic. Are you following me? That’s our junk from the curb, lawn, highway, or parking lot bobbing around in the world’s oceans.
A shed, mobile home, or house can be inundated or swept away during a flood. Everything inside (household chemicals, gasoline, fuel oil, pesticides, insulation, all those plastics, etc.) instantly pollutes the water. Many communities that rely on the Susquehanna River for drinking water are immediately impacted, including Lancaster, PA and Baltimore, MD. This dumpster was swept away from a parking lot in a floodplain. It rolled in the current, chipping away at the bridge before spilling the rubbish into the muddy water. After the flood receded, the dumpster was found a mile downstream. Its contents are still out there somewhere.Floodplains along the lower Susquehanna River are blanketed with a layer of flotsam that settles in place as high water recedes. These fresh piles can be several feet deep and stretch for miles. Nature decomposes the organic twigs and driftwood to build soil-enriching humus. However, the plastics and other man-made materials that do not readily decay or do not float away toward the sea during the next flood are incorporated into the alluvium and humus creating a “garbage soil”. Over time, the action of abrasives in the soil will grind small particles of plastics from the larger pieces. These tiny plastics can become suspended in the water column each time the river floods. What will be the long-term impact of this type of pollution?Anything can be swept away by the powerful hydraulic forces of flowing water. Large objects like this utility trailer can block passages through bridges and escalate flooding problems.The cost of removing debris often falls upon local government and is shared by taxpayers.Here, a junked boat dock is snagged on the crest of the York Haven Dam at Conewago Falls. Rising water eventually carried it over the dam and into the falls where it broke up. This and tons of other junk are often removed downstream at the Safe Harbor Dam to prevent damage to turbine equipment. During periods of high water, the utility hauls debris by the truck-load to the local waste authority for disposal. For the owners of garbage like this dock, it’s gone and it’s somebody else’s problem now.Motor vehicles found after floating away from parking areas in floodplains can create a dangerous dilemma for police, fire, and E.M.S. personnel, particularly when no one witnesses the event. Was someone driving this car or was it vacant when it was swept downstream? Should crews be put at risk to locate possible victims?
Beginning in 1968, participating municipalities, in exchange for having coverage provided to their qualified residents under the National Flood Insurance Program, were required to adopt and enforce a floodplain management ordinance. The program was intended to reduce flood damage and provide flood assistance funded with premiums paid by potential victims. The program now operates with a debt incurred during severe hurricanes. Occurrences of repetitive damage claims and accusations that the program provides an incentive for rebuilding in floodplains have made the National Flood Insurance Program controversial.
In the Lower Susquehanna River Watershed there are municipalities that still permit new construction in floodplains. Others are quite proactive at eliminating new construction in flood-prone zones, and some are working to have buildings removed that are subjected to repeated flooding.
Another Wall— Here’s an example of greed by the owner, engineer, and municipality… placing their financial interests first. The entire floodplain on the north side of this stream was filled, then the wall was erected to contain the material. A financial institution’s office and parking lot was constructed atop the mound. This project has channelized the stream and completely displaced half of the floodplain to a height of 15 to 20 feet. Constructed less than five years ago, the wall failed already and has just been totally reconstructed. The photo reveals how recent flooding has begun a new erosion regime where energy is focused along the base of the wall. Impairment of a floodplain to this degree can lead to flooding upstream of the site and erosion damage to neighboring infrastructure including roads and bridges.The floodplain along this segment of the lower Swatara Creek in Londonderry Township, Dauphin County is free to flood. Ordinances prohibit new construction here and 14 older houses that repeatedly flooded were purchased, dismantled, and removed using funding from the Federal Emergency Management Agency (F.E.M.A). A riparian buffer was planted and some wetland restorations were incorporated into stormwater management installations along the local highways. When the waters of the Swatara rise, the local municipality closes the roads into the floodplain. Nobody lives or works there anymore, so no one has any reason to enter. There’s no need to rescue stubborn residents who refused advice to evacuate. Sightseers can park and stand on the hill behind the barricades and take all the photographs they like.A new Pennsylvania Turnpike bridge across Swatara Creek features wide passage for the stream below. Water flowing in the floodplain can pass under the bridge without being channelized toward the path where the stream normally flows in the center. The black asterisk-shaped floats spin on the poles to help deflect debris away from the bridge piers. (flood crest on July 26, 2018)People are curious when a waterway floods and they want to see it for themselves. Wouldn’t it be wise to anticipate this demand for access by being ready to accommodate these citizens safely? Isn’t a parking lot, picnic area, or manicured park safer and more usable when overlooking the floodplain as opposed to being located in it? Wouldn’t it be a more prudent long-term investment, both financially and ecologically, to develop these improvements on higher ground outside of flood zones?Now would be a good time to stop the new construction and the rebuilding in floodplains. Aren’t the risks posed to human life, water quality, essential infrastructure, private property, and ecosystems too great to continue?Isn’t it time to put up the white flag and surrender the floodplains to the floods? That’s why they’re there. Floodplains are for flooding.
There are two Conewago Creek systems in the Lower Susquehanna River Watershed. One drains the Gettysburg Basin west of the river, mostly in Adams and York Counties, then flows into the Susquehanna at the base of Conewago Falls. The other drains the Gettysburg Basin east of the river, flowing through Triassic redbeds of the Gettysburg Formation and York Haven Diabase before entering Conewago Falls near the south tip of Three Mile Island. Both Conewago Creeks flow through suburbia, farm, and forest. Both have their capacity to support aquatic life impaired and diminished by nutrient and sediment pollution.
This week, some of the many partners engaged in a long-term collaboration to restore the east shore’s Conewago Creek met to have a look at one of the prime indicators of overall stream habitat health—the fishes. Kristen Kyler of the Lower Susquehanna Initiative organized the effort. Portable backpack-mounted electrofishing units and nets were used by crews to capture, identify, and count the native and non-native fishes at sampling locations which have remained constant since prior to the numerous stream improvement projects which began more than ten years ago. Some of the present-day sample sites were first used following Hurricane Agnes in 1972 by Stambaugh and Denoncourt and pre-date any implementation of sediment and nutrient mitigation practices like cover crops, no-till farming, field terracing, stormwater control, nutrient management, wetland restoration, streambank fencing, renewed forested stream buffers, or modernized wastewater treatment plants. By comparing more recent surveys with this baseline data, it may be possible to discern trends in fish populations resulting not only from conservation practices, but from many other variables which may impact the Conewago Creek Warmwater Stream ecosystem in Dauphin, Lancaster, and Lebanon Counties.
So here they are. Enjoy these shocking fish photos.
Matt Kofroth, Watershed Specialist with the Lancaster County Conservation District, operates the electrofishing wand in Conewago Creek while his team members prepare to net and collect momentarily-stunned fish. Three other electrofishing units operated by staff from the Susquehanna River Basin Commission and aided by teams of netters were in action at other sample locations along the Conewago on this day.Really big fish, such as this Common Carp (Cyprinus carpio), were identified, counted, and immediately returned to the water downstream of the advancing electrofishing team. Koi of the garden pond are a familiar variety of Common Carp, a native of Asia.Other fish, such as the Swallowtail Shiner, Redbreast Sunfish (Lepomis auritus), Fallfish, and suckers seen here, were placed in a sorting tank.Fallfish (Semotilus corporalis) are very active and require plenty of dissolved oxygen in the water to survive. Fallfish, Rainbow Trout (Oncorhynchus mykiss), and Smallmouth Bass (Micropterus dolomieu) were quickly identified and removed from the sorting tank for release back into the stream. Other larger, but less active fish, including suckers, quickly followed.Small fish like minnows were removed from the sorting tank for a closer look in a hand-held viewing tank. This Fathead Minnow (Pimephales promelas) was identified, added to the tally sheet, and released back into the Conewago. The Fathead Minnow is not native to the Susquehanna drainage. It is the minnow most frequently sold as bait by vendors.A breeding condition male Bluntnose Minnow (Pimephales notatus).The Cutlips Minnow (Exoglossum maxillingua) is a resident of clear rocky streams. Of the more than 30 species collected during the day, two native species which are classified as intolerant of persisting stream impairment were found: Cutlips Minnow and Swallowtail Shiner.This young River Chub (Nocomis micropogon) is losing its side stripe. It will be at least twice as large at adulthood.The Eastern Blacknose Dace (Rhinichthys atratulus) is found in clear water over pebble and stone substrate..The Longnose Dace (Rhinichthys cataractae) is another species of pebbly rocky streams.A juvenile Golden Shiner (Notemigonus crysoleucas). Adults lack the side stripe and grow to the size of a sunfish.A Swallowtail Shiner (Notropis procne) and a very young White Sucker (Catostomus commersonii) in the upper left of the tank.A Spotfin Shiner (Cyprinella spiloptera).A breeding male Spotfin Shiner. Show-off!The Margined Madtom (Noturus insignis) is a small native catfish of pebbly streams.The Banded Killifish (Fundulus diaphanus) is adept at feeding upon insects, including mosquitos.A young Rock Bass (Ambloplites rupestris). This species was introduced to the Susquehanna and its tributaries.The Greenside Darter (Etheostoma blennioides) is not native to the Susquehanna basin. The species colonized the Conewago Creek (east) from introduced local populations within the last five years.The Tessellated Darter (Etheostoma olmstedi) is a native inhabitant of the Susquehanna and its tributaries.The stars of the day were the American Eels (Anguilla rostrata).After collection, each eel was measured and weighed using a scale and dry bucket. This specimen checked in at 20 inches and one pound before being released.Prior to the construction of large dams, American Eels were plentiful in the Susquehanna and its tributaries, including the Conewago. They’ve since been rarities for more than half a century. Now they’re getting a lift.American Eels serve as an intermediate host for the microscopic parasitic glochidia (larvae) of the Eastern Elliptio (Elliptio complanata), a declining native freshwater mussel of the Lower Susquehanna River Watershed. While feeding on their host (usually in its gills), the glochidia cause little injury and soon drop off to continue growth, often having assured distribution of their species by accepting the free ride. Freshwater mussels are filter feeders and improve water quality. They grow slowly and can live for decades.American Eels are a catadromous species, starting life as tiny glass eels in the saltwater of the Atlantic Ocean, then migrating to tidal brackish marshes and streams (males) or freshwater streams (females) to mature. This 20-incher probably attempted to ascend the Susquehanna as an elver in 2016 or 2017. After hitching a ride with some friendly folks, she bypassed the three largest dams on the lower Susquehanna (Conowingo, Holtwood, and Safe Harbor) and arrived in the Conewago where she may remain and grow for ten years or more. To spawn, a perilous and terminally fatal journey to the Sargasso Sea awaits her. (You may better know the area of the Sargasso Sea as The Bermuda Triangle…a perilous place to travel indeed!)
SOURCES
Normandeau Associates, Inc. and Gomez and Sullivan. 2018. Muddy Run Pumped Storage Project Conowingo Eel Collection Facility FERC Project 2355. Prepared for Exelon.
Stambaugh, Jr., John W., and Robert P. Denoncourt. 1974. A Preliminary Report on the Conewago Creek Faunal Survey, Lancaster County, Pennsylvania. Proceedings of the Pennsylvania Academy of Sciences. 48: 55-60.
It seems as though the birds have grown impatient for typical spring weather to arrive. The increase in hours of daylight has signaled them that breeding time is here. No further delays can be entertained. They’ve got a schedule to keep.
Thursday, March 29: Winds began blowing from the southwest, breaking a cold spell which had persisted since last week’s snowfall. Birds were on the move ahead of an approaching rainy cold front.
Friday, March 30: Temperatures reached 60 degrees at last. Birds were again moving north through the day, despite rain showers and a change in wind direction—from the northwest and cooler following the passage of the front in the late morning.
Flocks of Double-crested Cormorants followed the Susquehanna River north in numerous V-shaped flocks during the recent several days.There were Turkey Vultures by the hundreds on the way north.And nearly as many Black Vultures too.
Saturday, March 31: It was cooler, but birds were still on the wing headed north.
At sunrise, a migrating Northern Flicker stopped by at a suet feeder to refuel.Osprey pairs have arrived at nest sites on the lower Susquehanna.
Sunday, April 1: The morning was pleasant, but conditions became cooler and breezy in the afternoon. Migratory and resident birds began feeding ahead of another storm.
A distant flock of fast-flying Bonaparte’s Gulls (Chroicocephalus philadelphia) moves expeditiously up the Susquehanna at Conewago Falls as winds begin to pick up during the late morning. Are they hurrying to get north of the path of the forthcoming weather system?A Mourning Dove (Zenaida macroura) feeds in anticipation of a snowy night ahead.A male Downy Woodpecker devours a late-afternoon meal.This Tufted Titmouse (Baeolophus bicolor), a cavity-nesting species, is distracted by a potential new home.Dark-eyed Juncos winter in the lower Susquehanna valley. During the month of April, they will begin departing for their breeding grounds, some nesting in the mountains just to our north.Tufted Titmouse…still house hunting.A male American Goldfinch is progressing through molt into a showy breeding (alternate) plumage.A male House Finch takes a break from its melodious song to feed before the arrival of our next spring snow. His mate is already incubating eggs in a nest not far away.Northern Cardinals (Cardinalis cardinalis) feed through the late afternoon, often as the last birds out-and-about before darkness. This male remains close to his mate as she forages beneath nearby shrubs.
Monday, April 2: Snow fell again, overnight and through the morning—a couple of inches. Most of the snow had melted away by late afternoon.
Horned Larks are plentiful in large open bare-soil (tilled) farmlands in winter, particularly near fresh manure. Their sandy-tan coloration hides them well, and they are seldom noticed unless spotted at roadside following snow storms. Horned Larks are migratory ground-nesting birds found in many sparsely vegetated habitats including tundra, parched fields and prairies, beaches, and even airports. There is a breeding population in the lower Susquehanna valley which may be increasingly attracted to favorable nesting habitat created in some no-till fields, possibly using a window of opportunity between the demise of cold-season cover crops and the ascendency of the warm-season crops to complete a brood cycle. Comparing the site selection and success rates of nesting Horned Larks under various crop management methods, including reactions to herbicide use, could be an enlightening study project for inquisitive minds. (Hint-Hint)The dainty Chipping Sparrow has arrived. This species commonly nests in small trees, often in suburban gardens.
