Heat Flux Processes in Streams and Their Impact on Coldwater and Coolwater Fishes

The deluge of rain that soaked the lower Susquehanna watershed during last week is now just a memory.  Streams to the west of the river, where the flooding courtesy of the remnants of Hurricane Debby was most severe, have reached their crest and receded.  Sliding away toward the Chesapeake and Atlantic is all that runoff, laden with a brew of pollutants including but not limited to: agricultural nutrients, sediment, petroleum products, sewage, lawn chemicals, tires, dog poop, and all that litter—paper, plastics, glass, Styrofoam, and more.  For aquatic organisms including our freshwater fish, these floods, particularly when they occur in summer, can compound the effects of the numerous stressors that already limit their ability to live, thrive, and reproduce.

(Environmental Protection Agency image)

One of those preexisting stressors, high water temperature, can be either intensified or relieved by summertime precipitation.  Runoff from forested or other densely vegetated ground normally has little impact on stream temperature.  But segments of waterways receiving significant volumes of runoff from areas of sun-exposed impervious ground will usually see increases during at least the early stages of a rain event.  Fortunately, projects implemented to address the negative impacts of stormwater flow and stream impairment can often have the additional benefit of helping to attenuate sudden rises in stream temperature.

Stream Subjected to Agricultural Runoff
While a row of trees along a creek can help provide protection from the thermal impact of the sun, a vegetative riparian buffer must be much wider to be effective for absorbing, cooling, and treating runoff from fields, lawns, and paved surfaces.  This buffer is too narrow to prevent surface runoff from polluting the water.

Of the fishes inhabiting the Lower Susquehanna River Watershed’s temperate streams, the least tolerant of summer warming are the trouts and sculpins—species often described as “coldwater fishes”.  Coldwater fishes require water temperatures below 70° Fahrenheit to thrive and reproduce.  The optimal temperature range is 50° to 65° F.  In the lower Susquehanna valley, few streams are able to sustain trouts and sculpins through the summer months—largely due to the effects of warm stormwater runoff and other forms of impairment.

Blue Ridge Sculpin
Sculpins, including the Blue Ridge Sculpin (Cottus caeruleomentum) seen here, are native coldwater fishes which, during the 11,000 years since the last glacial maximum, have had the availability of their favored habitat sharply reduced by warming water temperatures and a rising Atlantic.  During this interval, seawater has inundated the path of the “Late” Pleistocene lower Susquehanna which passed through the section of flooded river watershed we now call Chesapeake Bay and continued across the continental shelf to what was, during the glacial maximum, the river’s mouth at Norfolk Canyon.  Today, cut off from neighboring drainage basins, sculpins survive exclusively in cold headwaters, and only in those where human alterations including pollution, dams, channelization, and reduced base flow haven’t yet eliminated their isolated populations.  Formerly believed to be composed of two widespread North American species, the Slimy Sculpin (Cottus cognatus) and the Mottled Sculpin (Cottus bairdii), study in recent decades is discovering that sculpin populations in the present-day lower Susquehanna and neighboring Potomac headwaters consist of at least three newly delineated species: Blue Ridge Sculpin, Potomac Sculpin (Cottus gerardi), and Checkered Sculpin (Cottus sp.), the latter an as yet undescribed species found only in the refugium of limestone springs in the Potomac drainage in West Virginia; Frederick and Washington Counties, Maryland; and Franklin County, Pennsylvania.  (United States Geological Survey image)
Ice Age Susquehanna
Stare at this for a little while, you’ll figure it out…………More than 11,000 years ago, during the last glacial maximum, when sea level was about 275 feet lower than it is today, there was no Chesapeake Bay, just a great Susquehanna River that flowed to the edge of the continental shelf and its mouth at Norfolk Canyon.  It was a river draining taiga forests of pine, spruce , and fir, and it carried along the waters of all the present-day bay’s tributaries and more.  The section of the river’s watershed we presently call the lower Susquehanna was, at the time, the upper Susquehanna watershed.  Brook Trout and sculpins had the run of the river and its tributaries back then.  And the entire watershed was a coldwater fishery, with limestone and other groundwater springs providing not refuge from summer heat, but a place to escape freezing water.  (United States Geological Survey base image)
Norfolk Canyon, the mouth of the Susquehanna River during the most recent glacial maximum, now lies more than 275 feet below the surface of the ocean and plunges to more than a mile in depth along the finger of out wash from the gorge.  (United States Geological Survey image)
Rainbow. Brown, and Brook Trout
Tens of thousands of trout are raised in state-operated and cooperative nurseries for stocking throughout the lower Susquehanna valley.  These rearing facilities are located on spring-fed headwaters with sufficient flow to assure cold temperatures year round.  While the Rainbow Trout and Brown Trout (Salmo trutta) are the most commonly stocked species, the Brook Trout (Salvelinus fontinalis) is the only one native to American waters.  It is the least tolerant of stream warming and still reproduces in the wild only in a few pristine headwaters streams in the region.  During spring, all three of these species have been observed on rare occasions entering the fish lift facilities at the hydroelectric dams on the river, presumably returning to the Susquehanna as sea-run trout.

Coldwater fishes are generally found in small spring-fed creeks and  headwaters runs. Where stream gradient, substrate, dissolved oxygen, and other parameters are favorable, some species may be tolerant of water warmer than the optimal values.  In other words, these temperature classifications are not set in stone and nobody ever explained ichthyology to a fish, so there are exceptions.  The Brown Trout for example is sometimes listed as a “coldwater transition fish”, able to survive and reproduce in waters where stream quality is exceptionally good but the temperature may periodically reach the mid-seventies.

Eastern Blacknose Dace
The Eastern Blacknose Dace is sometimes classified as a “coldwater transition fish”.   It can be found in headwaters runs as well as in creeks with good water quality.
Longnose Dace
The Longnose Dace is another “coldwater transition fish” known only from clear, clean, flowing waters.

More tolerant of summer heat than the trouts, sculpins, and daces are the “coolwater fishes”—species able to feed, grow, and reproduce in streams with a temperature of less than 80° F, but higher than 60° F.  Coolwater fishes thrive in creeks and rivers that hover in the 65° to 70° F range during summer.

Creek Chubs
The Creek Chub is a familiar species of “coolwater fish” seldom found remaining in waters exceeding 80 degrees Fahrenheit.
The Yellow Perch (Perca flavescens) was perhaps the most frequently targeted coolwater “gamefish” in the Lower Susquehanna River Watershed prior to the introduction of the Northern Pike (Esox lucius) and Muskellunge (Esox masquinongy).  Today’s prevalence of warmwater streams and the dozens of species of non-native predatory fishes now naturalized within them have left the Yellow Perch populations greatly reduced and all but forgotten by anglers.  Out of sight, out of mind.  (National Park Service image)

What are the causes of modern-day reductions in coldwater and coolwater fish habitats in the lower Susquehanna River and its hundreds of miles of tributaries?  To answer that, let’s take a look at the atmospheric, cosmic, and hydrologic processes that impact water temperature.  Technically, these processes could be measured as heat flux—the rate of heat energy transfer per unit area per unit time, frequently expressed as watts per meter squared (W/m²).  Without getting too technical, we’ll just take a look at the practical impact these processes have on stream temperatures.

HEAT FLUX PROCESSES IN A SEGMENT OF STREAM

Heat Flux Processes on Stream and River Segments.  These processes could be measured as heat flux—the rate of heat energy transfer per unit area per unit time.  (Environmental Protection Agency image)
      • INCOMING TEMPERATURE AND FLOW—The baseline temperature of stream water entering a given segment of waterway is obviously the chief factor determining its temperature when exiting that segment.  Incoming temperature and flow also determine the water’s susceptibility to heat absorption or loss while transiting the segment.  Lower flows may subject the given volume of water to a greater loss or gain of heat energy during the time needed to pass through the segment than the same volume at a higher flow.  Lower flows may also reduce stream velocity and extend a given volume of water’s exposure time to the exchange of heat energy while moving through the segment.  Generally speaking…
        1. …the higher the stream flow, the less a given volume of that stream’s  water may be impacted by the effects of the heat flux processes within the segment.
        2. …the lower the stream flow, the more a given volume of that stream’s water may be impacted by the effects of the heat flux processes within that segment.
        3. …the temperature and flow rate of precipitation entering the segment are factors that determine the impact of its heat energy transfer to or from a given volume of the stream’s waters.
        4. …the temperature and flow rate of runoff and point-source discharges entering the segment are factors that determine the impact of their heat energy transfer to or from a given volume of the stream’s waters.
Stormwater Discharge into Channelized Creek
Stormwater from impervious surfaces including roads, parking lots, roofs, and lawns quickly impacts temperatures in small creeks.  Channelized  streams are availed few of the positive attributes provided by many of the heat flux processes we’re about to see.  They therefore suffer from severe impairment and are exposed to temperature extremes that few aquatic organisms can survive.  Runoff from sun-heated pavement during a summer thunderstorm can often exceed 100 degrees Fahrenheit and can, at sufficient flow rate, quickly raise the temperature of a small stream to well over 90 degrees.
Stormwater Runoff
Stormwater runoff not only poses a thermal threat to waterways, its a significant source of a wide variety of pollutants.
      • GROUNDWATER INPUT—In streams connected to the aquifer, the temperature in a flowing segment can be impacted by the influx of cold groundwater.  With temperatures ranging from about 52° to 60° Fahrenheit, groundwater will absorb heat from the stream in summer, and warm it in the winter.  In warmwater streams, coldwater and coolwater fishes will often seek areas of the substrate where groundwater is entering for use as refugium from the summer heat.  Yellow Perch in the lower Susquehanna are known to exhibit this behavior.
Creeks and rivers connected to the aquifer and receiving supplemental flow from it are known as “gaining streams”. These streams frequently feed water into the aquifer as well. (United States Geological Survey image)
When flowing through an area experiencing drought or an excessive removal of groundwater (lots of wells, etc.), a waterway can become a “losing stream”, one that surrenders a portion of its flow to recharge the aquifer.  Further downstream, the reduced flow can make such a creek or river more susceptible to the effects of heat flux processes.  (United States Geological Survey image)
Seriously depleted aquifers can lead to a “disconnected stream”.  Smaller waterways subjected to these conditions will sometimes lose all their flow to the ground, often causing a catastrophic failure of the aquatic ecosystem supported therein.  (United States Geological Survey image)
Urban Flooding and Dry Streambed
Urban runoff overwhelms this small stream with polluted water than can reach temperatures of 100 degrees or more (left), then lets it high and dry with no baseflow during periods of dry weather (right) as the waterway becomes disconnected from the much-depleted aquifer.
Stormwater Retention Basin
Well-designed and properly constructed stormwater retention basins not only recharge groundwater supplies for wells and streams, they can also help prevent thermal pollution in waterways.  Planted with native wetland species and allowed to thrive, they can become treasured wildlife islands in otherwise inhospitable environs.  The benefits don’t stop there; plants also help sequester nutrients contained in the runoff.
      • HYPORHEIC EXCHANGE—Related to groundwater input, hyporheic exchange is the slow movement of water through the rock, sand, gravel, and soils composing the streambed, saturated shoreline, shallow aquifer, and connected floodplain of a creek or river.  As a heat flux process, hyporheic exchange helps moderate extremes in seasonal water temperatures by conducting energy between the solid materials in the zone and the flowing water.  Hyporheic zones are important habitats for many species of aquatic invertebrates and spawning fish.  Natural chemical processes within these zones convert ammonia-producing wastes into nitrite, then nitrate, allowing it to be absorbed as food by plants growing in the stream or in the alluvium within the zone.  Vegetation removal, channelization, legacy sediments, silt deposits, and man-made walls and dams can negate the benefits of hyporheic exchange.
Exchange of surface and ground water within the hyporheic zone is most directly associated with high-gradient (left) and meandering (right) segments of streams. (United States Geological Survey image)
Legacy Sediments and Fill
Very common on streams in the lower Susquehanna valley are these accumulations of legacy sediments at the sites of former mill ponds.  After the dams were removed, the creeks began eroding their way down through the mire as they tried to reestablish their floodplains and find their native substrate.  These trapped waterways are not only cut off from their hyporheic zones, they’re now a major source of nutrient and sediment pollution.  Misguided landowners like this one frequently dump fill into these sites to “save their land” and “control flooding”.  The fill and materials added to “shore up the banks” do nothing to fix what ails the creek, but instead displace more water to make the impact of flooding even more widespread.
Flooplain and Stream Restoration
Rehabilitation projects that remove legacy sediments help restore hyporheic exchange by reconnecting the stream to its underlying geology, its floodplain, and its wetlands.  Rising waters remain in the floodplain where they get a good bio-scrubbing and help replenish the creek and groundwater supply.  As the experts say, “floodplains are for flooding.”
      • ATMOSPHERIC EXCHANGE (CONVECTION, EVAPORATION)—Primarily a process by which a stream loses heat energy and cools its waters, atmospheric exchange is also a means by which a warm air mass can relinquish heat to cooler waters and thus increase their temperature.  This phenomenon can be dramatically enhanced when a stream passes through a so-called urban heat island where air temperatures remain warm through the night.  Convection, the movement of heat energy through a fluid (liquid or gas), causes warmer, less-dense water to rise to the surface of a stream, particularly where there is minimal turbulence.  When the air above is cooler than the water’s surface layer, the stream will conduct heat energy across the water/atmosphere interface causing the warmed air molecules to rise in a convection column.  If the atmospheric relative humidity is less than 100%, some surface water will vaporize—a process that expends more of the stream’s heat energy.  The rate of convective and evaporative cooling in a given stream segment is directly related to the degree of difference between the water temperature and air temperature, and to the relative humidity in the air mass above the lake, creek, or river.  The mechanical action of stream turbulence including rapids, riffles, and falls increases the contact area between air and water to maximize the atmospheric exchange of heat energy.  The convective air current we call surface wind has a turbulent wave-producing effect on water that can also maximize atmospheric exchange; think of a cold autumn wind robbing heat energy from a warm lake or river or a hot summer wind imparting its heat to a cooler creek.  These exchanges are both conductive in nature (air-to-water/water-to-air) and evaporative, the latter being expedited by the movement of dry air over warm water.
Tessellated Darter
Usually classified as one of the coolwater fishes, the bottom-dwelling Tessellated Darter can thrive in the warmer creeks and in the main stem of the Susquehanna by inhabiting riffles where atmospheric exchange in the form of increased evaporation helps reduce temperatures and convective currents carry the cooler, well-oxygenated water to the streambed.
Three mile Island Unit 1 Cooling Towers
Humans utilize the concept of atmospheric exchange, adopting the phenomena of evaporation and convection to cool the hot waters produced during electric generation and other industrial processes before discharge into a lake or river.
      • STREAMBED CONDUCTIVE EXCHANGE—In the lower Susquehanna watershed, there may be no better natural example of streambed conductive exchange than the Triassic-Jurassic diabase pothole bedrocks of Conewago Falls on the river at the south end of Three Mile Island.
During sunny days, the massive diabase pothole rocks at Conewago Falls absorb solar (shortwave) radiation, then conduct that heat energy into the flowing water, often continuing to pass the accumulated warmth into the river during the night.  On cloudy days, the riverbed collects longwave atmospheric radiation, a heat flux process that yields significantly less energy for conduction into the rapids, riffles, and pools of the falls.  During periods of low river flow, the heating effect of streambed conductive exchange can become magnified.  Compared to conditions that prevail when torrents of turbid water are rushing through the falls, partially exposed bedrock surrounded by clear water collects radiated energy much more efficiently, then conducts the heat to a greatly reduced volume of passing water.  During summer and autumn, this process can create a mix of temperature zones within the falls with warmer water lingering in slow-moving pools and cooler water flowing in the deeper fast-moving channels.  Along the falls’ mile-long course, a haven is created for aquatic organisms including warmwater and some coolwater fishes, oft times attracting anglers and a variety of hungry migrating birds as well.
Fallfish
Classified as one of our coolwater fishes, the Fallfish finds favorable conditions for feeding, growing, and spawning in the well-oxygenated waters of Conewago Falls.
Northern Hog Sucker
Though the lower Susquehanna River is classified as a warmwater fishery, the Northern Hog Sucker (Hypentelium nigricans), another of our native coolwater fishes, finds the fast-moving waters of Conewago Falls to its liking.  Northern Hog Suckers are known to inhabit streams cold enough to host trout.  They exhibit remarkable home range fidelity, sometimes spending their entire lives occupying the same several hundred feet of waterway.  Northern Hog Suckers are often designated an indicator of good water quality, intolerant of many stream impairment parameters.  Their presence in Conewago Falls provides testament to the quality of the warmwater fishery there.
Severely Impaired Channelized Stream
An unnatural example.  The reduced base flow in this channelized and severely impaired creek has been rendered vulnerable to the negative impacts of several heat flux processes including streambed conductive exchange.  Urban stormwater/surfacewater inflow, solar (shortwave) radiation, and heat conducted into the stream from the masonry walls, curbs, and raceway can all conspire to cook aquatic organisms with life-quenching summer water temperatures exceeding 90 degrees Fahrenheit.
      • SOLAR (SHORTWAVE) RADIATION—The sun provides the energy that fuels the earth’s complex climate.  The primary heat flux process that heats our planet is the absorption of solar radiation in the shortwave spectrum, which includes ultraviolet, visible, and infrared frequencies at the upper end of the longwave spectrum.  Streams and other bodies of water absorb the greatest amounts of solar (shortwave) radiation during the weeks around summer solstice when the sun at mid-day is closer to zenith than at any other time of the year.  However, the heating impact of the radiation may be greatest when the volume of water in the creek, river, or lake is at its minimum for the year—often during early fall.
The rate, measured in watts per square meter, at which solar (shortwave) energy is directly radiated to a given area on the earth’s surface (including streams and other waters) is determined by: solar activity, the angle of the sun in the sky, aspect (slope) of the receiving surface, the opacity of the overlying atmosphere, and the distance of the earth from the sun.  The former varies with the year’s seasons, the time of day, and the latitude of a given area.  The latter is currently at its annual minimum when earth is at perihelion during the early days of January, thus providing the northern hemisphere with a little bump in radiation during the shortest days of the year when the sun is at its lowest angle in the sky.  (NASA image)
A varying portion of the solar (shortwave) radiation reaching the earth is reflected back into space by clouds.  A smaller share is absorbed by the atmosphere, thus heating it.  An even lesser quantity is reflected back into space by water and land.  The remainder of the energy is absorbed by the planet’s surfaces, its water and land. (NASA image)
      • INCIDENT SHORTWAVE RADIATION—Also known as insolation (incoming solar radiation), incident shortwave radiation is the sum total energy of both the direct solar radiation that travels to the earth’s surface unaffected by the atmosphere and the diffuse radiation, waves that have been weakened and scattered by constituents of the atmosphere before reaching the planet’s surface.  On a cloudy day, the warming of terrestrial surfaces including streams and other bodies of water is the result of diffuse radiation.  On days with any amount of sunshine at all, both direct and diffuse radiation heat our waters and lands.
Pumkinseed
Warmwater fishes such as the native Pumpkinseed (Lepomis gibbosus) thrive in sun-drenched 70-to-85-degree waters as long as other heat flux processes prevent sudden temperature increases and oxygen depletion.
Mowed Stream Bank
Mowed stream banks offer a waterway no protection from incoming solar (shortwave) radiation, nor terrestrial forms of impairment including nutrient-rich stormwater runoff and silt.
      • REFLECTED SHORTWAVE RADIATION—known as albedo, reflected solar (shortwave) radiation is energy directed away from the earth’s surface before being absorbed.  A surface’s albedo value is basically determined by its color, black having little reflective value, white and silvery surfaces reflecting nearly all solar (shortwave) radiation away.  A surface with no reflective properties has an albedo value of 0, while a totally reflective surface has a value of 1.  Clean snow with a value of about 0.85 to 0.9 (85% to 90%) is a highly reflective surface; yellow snow isn’t as good.  A stream, river, or lake blanketed with ice and snow will absorb very little solar energy and will rely upon other heat flux processes to trigger a melt and thaw.  The surface of open water has a varying albedo value determined mostly by the angle of the sun.  Solar radiation striking the water’s surface at a low angle is mostly reflected away, while that originating at an angle closer to zenith is more readily absorbed.
Forested Stream
To avoid the heating effects of solar (shortwave) and atmospheric longwave radiation, coldwater and coolwater fishes require streams offering protection from full exposure to direct sunlight and cloud cover.  Runs and creeks flowing beneath a closed canopy of forest trees are shielded from 25% or more of incoming radiation and are thus able to better maintain thermal stability during the most vulnerable period of the year for temperature-sensitive fishes, May through October.
      • LONGWAVE RADIATION—Radiation in the longwave spectrum is composed of infrared waves at frequencies lower than those of the shortwave spectrum.  Longwave radiation, sometimes just called infrared radiation, is produced by the earth and its atmosphere and is propagated in all directions, day and night.  It warms mostly the lower atmosphere which in turn warms the earth’s surface including its waters.  Some longwave energy can even be radiated into the waterway from its own streambed—and the stream can return the favor.  Other forms of mass surrounding  a stream such as a rocky shoreline or a man-made structure such as bridge pier can trade longwave radiation with a waterway.  The effect of these latter exchanges is largely trivial and never rivals the heat flux transfer of warm to cold provided by  conduction.
Longwave radiation emissions slow as the temperature of the emitting mass decreases, just as they also increase with temperature of the mass.  Longwave radiation emissions therefore decrease with altitude along with the temperature of the water vapor, carbon dioxide, methane, and other gases that produce them.  As such, the highest reaches of the atmosphere have a greatly reduced capability of shedding longwave radiation into space.  At ground level, lakes, creeks, and streams receive their greatest dose of longwave radiation while beneath the cover of low-lying clouds or fog.  (NASA image)
      • CANOPY RADIATION—Trees emit longwave radiation that may have a limited heat flux impact on waterway temperature.  This radiation is diffuse, of scattered effect, and scarcely detectable, particularly beneath multilayered dense canopies.  Some of the infrared energy transmitted by the tree canopy is radiated skyward as well.
      • WATER RADIATION—Water, like all earthly matter composed of vibrating molecules, emits longwave radiation.  This heat flux process provides an ongoing cooling effect to streams, rivers, lakes, and oceans—warmer ones shedding infrared energy at a faster rate than those that are cold.

Now that we have a basic understanding of the heat flux processes responsible for determining the water temperatures of our creeks and rivers, let’s venture a look at a few graphics from gauge stations on some of the lower Susquehanna’s tributaries equipped with appropriate United States Geological Survey monitoring devices.  While the data from each of these stations is clearly noted to be provisional, it can still be used to generate comparative graphics showing basic trends in easy-to-monitor parameters like temperature and stream flow.

Each image is self-labeled and plots stream temperature in degrees Fahrenheit (bold blue) and stream discharge in cubic feet per second (thin blue).

The West Conewago Creek drains much of the Gettysburg Basin’s Triassic redbeds in Adams and northern York Counties in Pennsylvania and includes a small headwaters area in northern Maryland.  The gauge station is located just a over a mile upstream from the waterway’s mouth on the Susquehanna just below Conewago Falls.  Right through the summer heatwave, this 90-day graph shows a consistent daily pattern of daytime rises in temperature and nighttime cooling.  To the right, a rapid cool down can be seen coinciding with two periods of high water, the first from a series of heavy thundershowers, the second from flooding caused by the remnants of Hurricane Debby.  Notice that the early August downpours were so heavy that they cooled the hot surface runoff and waterway quickly, without creating a rise in stream temperature at the gauging station.  Had this monitoring device been located on a small tributary in an area with an abundance of impervious surfaces, there would probably have been a brief rise in stream temperature prior to the cooldown.  (United States Geological Survey image)

The daily oscillations in temperature reflect the influence of several heat flux processes.  During the day, solar (shortwave) radiation and convection from summer air, especially those hot south winds, are largely responsible for the daily rises of about 5° F.  Longwave radiation has a round-the-clock influence—adding heat to the stream during the day and mostly shedding it at night.  Atmospheric exchange including evaporative cooling may help moderate the rise in stream temperatures during the day, and certainly plays a role in bringing them back down after sunset.  Along its course this summer, the West Conewago Creek absorbed enough heat to render it a warmwater fishery in the area of the gauging station.  The West Conewago is a shallow, low gradient stream over almost its entire course.  Its waters move very slowly, thus extending their exposure time to radiated heat flux and reducing the benefit of cooling by atmospheric exchange.  Fortunately for bass, catfish, and sunfish, these temperatures are in the ideal range for warmwater fishes to feed, grow, and reproduce—generally over 80° F, and ideally in the 70° to 85° F range.  Coolwater fishes though, would not find this stream segment favorable.  It was consistently above the 80° F maximum and the 60° to 70° F range preferred by these species.  And coldwater fishes, well, they wouldn’t be caught dead in this stream segment.  Wait, scratch that—the only way they would be caught in this segment is dead.  No trouts or sculpins here.

The Codorus Creek drains primarily the carbonate valleys of York County to the south of the West Conewago watershed.  This gauge station is located about a mile upstream from the creek’s mouth on the Susquehanna just below Haldeman Riffles.  The graphic pattern is very similar to that of the West Conewago’s: daily heating and cooling cycles and a noticeable drop in stream temperature in early August caused by a day of thundershowers followed by the remnants of Hurricane Debby.  (United States Geological Survey image)

Look closely and you’ll notice that although the temperature pattern on this chart closely resembles that of the West Conewago’s, the readings average about 5 degrees cooler.  This may seem surprising when one realizes that the Codorus follows a channelized path through the heart of York City and its urbanized suburbs—a heat island of significance to a stream this size.  Before that it passes through numerous impoundments where its waters are exposed to the full energy of the sun.  The tempering factor for the Codorus is its baseflow.  Despite draining a smaller watershed than its neighbor to the north, the Codorus’s baseflow (low flow between periods of rain) was 96 cubic feet per second on August 5th, nearly twice that of the West Conewago (51.1 cubic feet per second on August 5th).  Thus, the incoming heat energy was distributed over a greater mass in the Codorus and had a reduced impact on its temperature.  Though the Codorus is certainly a warmwater fishery in its lower reaches, coolwater and transitional fishes could probably inhabit its tributaries in segments located closer to groundwater sources without stress.  Several streams in its upper reaches are in fact classified as trout-stocked fisheries.

This is a zoomed-in look at the previous graph showing the impact of a rainfall event on the water temperatures in Codorus Creek.  Unlike the sharp declines accompanying the deluge of flood waters during the two events in early August, these lesser storms in late June generated just enough runoff to capture heat energy from impervious surfaces and warm the creek, temporarily breaking the daily heating/cooling cycle.  Upstream in the immediate area of the runoff, the impact on the stream and/or its tributaries was probably much more dramatic, certainly raising temperatures into the nineties or above.  (United States Geological Survey image)
Kreutz Creek drains a carbonate bedrock area of York County and flows parallel to the Lincoln Highway (US 30) to enter the Susquehanna at Wrightsville.  The gauging station is about one mile upstream from the creek’s mouth.   (United States Geological Survey image)

The Kreutz Creek gauge shows temperature patterns similar to those in the West Conewago and Codorus data sets, but notice the lower overall temperature trend and the flow.  Kreutz Creek is a much smaller stream than the other two, with a flow averaging less than one tenth that of the West Conewago and about one twentieth of that in the Codorus.  And most of the watershed is cropland or urban/suburban space.  Yet, the stream remains below 80° F through most of the summer.  The saving graces in Kreutz Creek are reduced exposure time and gradient.  The waters of Kreutz Creek tumble their way through a small watershed to enter the Susquehanna within twenty-four hours, barely time to go through a single daily heating and cooling cycle.  As a result, their is no chance for water to accumulate radiant and convective heat over multiple summer days.  The daily oscillations in temperature are less amplified than we find in the previous streams—a swing of about three degrees compared to five.  This indicates a better balance between heat flux processes that raise temperature and those that reduce it.  Atmospheric exchange in the stream’s riffles, forest cover, and good hyporheic exchange along its course could all be tempering factors in Kreutz Creek.  From a temperature perspective, Kreutz Creek provides suitable waters for coolwater fishes.

Muddy Creek drains portions of southern York County through rolling farmland and woodlots.  There are no large impoundments or widespread urban impacts in the watershed, which may help explain its slightly lower temperature trends.  (United States Geological Survey image)

Muddy Creek is a trout-stocked fishery, but it cannot sustain coldwater species through the summer heat.  Though temperatures in Muddy Creek may be suitable for coolwater fishes, silt, nutrients, low dissolved oxygen, and other factors could easily render it strictly a warmwater fishery, inhabited by species tolerant of significant stream impairment.

Chiques Creek drains mostly limestone farmland in northwestern Lancaster County.  The gauging station is located near the stream’s mouth on the Susquehanna at Chiques (Chickies) Rock.  Oscillations in temperature again resemble the other waterways, but daily highs remain almost entirely below 80 degrees.  (United States Geological Survey image)

A significant number of stream segments in the Chiques watershed have been rehabilitated to eliminate intrusion by grazing livestock, cropland runoff, and other sources of impairment.  Through partnerships between a local group of watershed volunteers and landowners, one tributary, Donegal Creek, has seen riparian buffers, exclusion fencing, and other water quality and habitat improvements installed along nearly ever inch of its run from Donegal Springs through high-intensity farmland to its mouth on the main stem of the Chiques just above its confluence with the Susquehanna.  The improved water quality parameters in the Donegal support native coldwater sculpins and an introduced population of reproducing Brown Trout.  While coldwater habitat is limited to the Donegal, the main stem of the Chiques and its largest tributary, the Little Chiques Creek, both provide suitable temperatures for coolwater fishes.

Limestone Formation on Little Chiques Creek
Streams in the Chiques Creek and similar limestone watersheds often pass through areas with significant bedrock formations.  Heat flux processes including groundwater input, hyporheic exchange, and streambed conductive exchange can have a greater influence on water temperature along these segments.
Eastern Blacknose Dace
A breeding condition Eastern Balcknose Dace, one of the coldwater transition fishes found in the Chiques and its tributaries.
Common Shiner
The Common Shiner (Luxilus cornutus), a fish tolerant of warmwater streams, prefers cool, clear waters for spawning.  For protection from late-spring and summer heat, breeding males may seek a section of creek with a streambed inflow of limestone groundwater to defend as their nesting territory.
A closeup of the Chiques Creek graph showing what appears to be a little bump in temperature caused by surface runoff during a couple of late-May showers.  Stream rehabilitation is an ongoing process and the pressures of land disturbances both old and new present challenges to those who make it their passion to fix the wrongs that have been inflicted upon our local waters.  Even the  exemplary Donegal Creek faces new threats from urbanization in one of its headwater areas several miles to the northwest of the historic springs.  (United States Geological Survey image)
Conewago Creek (East) drains primarily Triassic redbed farmlands in Dauphin, Lancaster, and Lebanon Counties.  Much of the headwaters area is forested but is experiencing an increasing rate of encroachment by housing and some commercial development.  Conewago Creek (East) enters the Susquehanna on the east side of Conewago Falls at Three Mile Island.  The watershed is equipped with three U.S.G.S. gauge stations capable of providing temperature data.  This first one is located just over a mile upstream of the creek’s mouth.  (United States Geological Survey image)

Despite its meander through and receipt of water from high-intensity farmland, the temperature of the lower Conewago (East) maxes out at about 85° F, making it ideal for warmwater fishes and even those species that are often considered coolwater transition fishes like introduced Smallmouth Bass, Rock Bass, Walleye, and native Margined Madtom.  This survivable temperature is a testament to the naturally occurring and planted forest buffers along much of the stream’s course, particularly on its main stem.  But the Conewago suffers serious baseflow problems compared to other streams we’ve looked at so far.  Just prior to the early August storms, flow was well below 10 cubic feet per second for a drainage area of more than fifty square miles.  While some of this reduced flow is the result of evaporation, much of it is anthropogenic in origin as the rate of groundwater removal continues to increase  and a recent surge in stream withdraws for irrigation reaches its peak during the hottest days of summer.

Juvenile Rock Bass
A juvenile Rock Bass.
A juvenile Margined Madtom.
A juvenile Margined Madtom.
A closer look at the Conewago Creek (East) graphic shows the temperature drop associated with a series of thundershowers and the remnants of Hurricane Debby in early August.  Despite the baseflow being below five cubic feet per second, the cooling effect of the downpours as measured in the area of the gauge was significant enough to overwhelm any heating of runoff that may have occurred as precipitation drained across hardened soils or man-made impervious surfaces.  (United States Geological Survey image)

A little side note—the flow rate on the Conewago at the Falmouth gauge climbed to about 160 cubic feet per second as a result of the remnants of Hurricane Debby while the gauge on the West Conewago at Manchester skyrocketed to about 20,000 cubic feet per second.  Although the West Conewago’s watershed (drainage area) is larger than that of the Conewago on the east shore, it’s larger only by a multiple of two or three, not 125.  That’s a dramatic difference in rainfall!

The Bellaire monitoring station on Conewago Creek (East) is located on the stream’s main stem just downstream from the mouth of Little Conewago Creek, a tributary with its origins in farmland and woodlots.  (United States Geological Survey image)

The temperatures at the Bellaire monitoring station, which is located upstream of the Conewago’s halfway point between its headwaters in Mount Gretna and its mouth, are quite comparable to those at the Falmouth gauge.  Although a comparison between these two sets of data indicate a low net increase in heat absorption along the stream’s course between the two points, it also suggests sources of significant warming upstream in the areas between the Bellaire gauge and the headwaters.

Data from the gauge site on the Little Conewago Creek shows a temperature averaging about five degrees cooler than the gauge several miles downstream on the main stem of the Conewago at Bellaire.  (United States Geological Survey image)

The waters of the Little Conewago are protected within planted riparian buffers and mature woodland along much of their course to the confluence with the Conewago’s main stem just upstream of Bellaire.  This tributary certainly isn’t responsible for raising the temperature of the creek, but is instead probably helping to cool it with what little flow it has.

Juvenile Eastern Blacknose Dace (top) and a juvenile Longnose Dace.
A stream like the Little Conewago Creek with daily temperatures that remain mostly below 80 degrees and retreat to 75 degrees or less during the night can be suitable for coldwater transition fishes like these juvenile Eastern Blacknose Dace (top) and Longnose Dace.

Though mostly passing through natural and planted forest buffers above its confluence with the Little Conewago, the main stem’s critically low baseflow makes it particularly susceptible to heat flux processes that raise stream temperatures in segments within the two or three large agricultural properties where owners have opted not to participate in partnerships to rehabilitate the waterway.  The headwaters area, while largely within Pennsylvania State Game Lands, is interspersed with growing residential communities where potable water is sourced from hundreds of private and community wells—every one of them removing groundwater and contributing to the diminishing baseflow of the creek.  Some of that water is discharged into the stream after treatment at the two municipal sewer plants in the upper Conewago.  This effluent can become quite warm during processing and may have significant thermal impact when the stream is at a reduced rate of flow.  A sizeable headwaters lake is seasonally flooded for recreation in Mount Gretna.  Such lakes can function as effective mid-day collectors of solar (shortwave) radiation that both warms the water and expedites atmospheric exchange.

The Conewago Creek (East) Watershed from the Bellaire U.S.G.S. Gauging Station (lower left) upstream to the headwaters in Mount Gretna.  (United States Geological Survey image)

Though Conewago Creek (East) is classified as a trout-stocked fishery in its upper reaches in Lebanon County, its low baseflow and susceptibility to warming render it inhospitable to these coldwater fishes by late-spring/early summer.

River Chub
Despite being considered a warmwater fish, the River Chub (Nocomis micropogon) will ascend streams like the Conewago to seek cooler, gravel-bottomed waters for spawning.  Reduced baseflow has probably rendered the stream currently too small for this species on Pennsylvania State Game Lands in Colebrook where this specimen was photographed in 2018.
Juvenile Golden Shiner
The Golden Shiner, another warmwater fish, often ascends streams to enter cooler water. Juvenile Golden Shiners like this one will move into shallower headwaters not only to seek reduced temperatures, but to escape large predatory fishes as well.
Irrigation using stream water.
Irrigation of agricultural fields using a large portion of the already diminished baseflow in the Conewago Creek (East) just downstream of the Bellaire gauging station.  Despite millions of dollars in investment to rehabilitate this Susquehanna valley stream, the riparian buffers and other practices can have little effect when the creek gets sucked down to just a trickle.  Low baseflow is a hard nut to crack.  It’s best prevented, not corrected.
Hammer Creek, a trout-stocked fishery, originates, in part, within Triassic conglomerate in the Furnace Hills of Lebanon County, then flows north into the limestone Lebanon Valley where it picks up significant flow from other tributaries before working its way south back through the Furnace Hills into the limestone farmlands of Lancaster County.  From there the stream merges with the Cocalico Creek, then the Conestoga River, and at last the Susquehanna.  Note the tremendous daily temperature oscillations on this headwaters stream as it surges about 15 degrees each day before recovering back close to groundwater temperature by sunrise the next day.  (United States Geological Survey image)
Headwaters of Hammer Creek including Buffalo Springs, a significant source of cold groundwater feeding the western leg of the stream.  The large dams on this section that created the Lebanon and Rexmont Reservoirs have been removed.  (United States Geological Survey base image)

The removal of two water supply dams on the headwaters of Hammer Creek at Rexmont eliminated a large source of temperature fluctuation on the waterway, but did little to address the stream’s exposure to radiant and convective heat flux processes as it meanders largely unprotected out of the forest cover of Pennsylvania State Game Lands and through high-intensity farmlands in the Lebanon Valley.  Moderating the temperature to a large degree is the influx of karst water from Buffalo Springs, located about two miles upstream from this gauging station, and other limestone springs that feed tributaries which enter the Hammer from the east and north.  Despite the cold water, the impact of the stream’s nearly total exposure to radiative and other warming heat flux processes can readily be seen in the graphic.  Though still a coldwater fishery by temperature standards, it is rather obvious that rapid heating and other forms of impairment await these waters as they continue flowing through segments with few best management practices in place for mitigating pollutants.  By the time Hammer Creek passes back through the Furnace Hills and Pennsylvania State Game Lands, it is leaning toward classification as a coolwater fishery with significant accumulations of sediment and nutrients.  But this creek has a lot going for it—mainly, sources of cold water.  A core group of enthusiastic landowners could begin implementing the best management practices and undertaking the necessary water quality improvement projects that could turn this stream around and make it a coldwater treasure.  An organized effort is currently underway to do just that.  Visit Trout Unlimited’s Don Fritchey Chapter and Donegal Chapter to learn more.  Better yet, join them as a volunteer or cooperating landowner!

Male Creek Chub
The male Creek Chub, one of our coolwater fishes, develops head tubercles and becomes flushed with color during spawning season.  Hammer Creek not only provides a home for the Creek Chub, its cold headwaters provide refuge for a population of native Brook Trout too.
Like no other example we’ve looked at so far, this closeup of the Hammer Creek graphic shows temperature bumps correlating with the stormwater runoff from early August’s rains.  Because the stream flow is small and the precipitation rate was not as great at this location, the effect of heat flux from runoff is more readily apparent.  (United States Geological Survey image)
Brook Trout adult and juvenile.  (United States Fish and Wildlife Service image by Ryan Hagerty)

For coldwater fishes, the thousands of years since the most recent glacial maximum have seen their range slowly contract from nearly the entirety of the once much larger Susquehanna watershed to the headwaters of only our most pristine streams.  Through no fault of their own, they had the misfortune of bad timing—humans arrived and found coldwater streams and the groundwater that feeds them to their liking.  Some of the later arrivals even built their houses right on top of the best-flowing springs.  Today, populations of these fishes in the region we presently call the Lower Susquehanna River Watershed are seriously disconnected and the prospect for survival of these species here is not good.  Stream rehabilitation, groundwater management, and better civil planning and land/water stewardship are the only way coldwater fishes, and very possibly coolwater fishes as well, will survive.  For some streams like Hammer Creek, it’s not too late to make spectacular things happen.  It mostly requires a cadre of citizens, local government, project specialists, and especially stakeholders to step up and be willing to remain focused upon project goals so that the many years of work required to turn a failing stream around can lead to success.

Riparian Buffer
Riparian buffers with fences to exclude livestock can immediately begin improving water quality.  With establishment of such vegetative buffers, the effects of stressors that otherwise eliminate coldwater and coolwater fishes from these segments will begin to diminish.
Riparian Buffer
Within five to ten years, a riparian buffer planted with native trees is not only helping to reduce nutrient and sediment loads in the stream, it is also shielding the waters from heat flux processes including the solar (shortwave) radiation that raises water temperatures to levels not tolerated by coldwater and coolwater fishes.
Riparian Buffer
A well-established riparian buffer.
Forested Stream
A forested stream.

You’re probably glad this look at heat flux processes in streams has at last come to an end.  That’s good, because we’ve got a lot of work to do.

Add one more benefit to the wildflower meadow, it infiltrates stormwater to recharge the aquifer much better than mowed grass.  And another related plus, it reduces runoff and its thermal pollution.  Besides, you don’t have time to mow grass, because we have work to do!
Potomac Sculpin
Our native coldwater fishes including the Potomac Sculpin will survive only if we protect and expand the scattered few habitats where they have taken refuge.  They have no choice but to live in these seriously threatened places, but we do.  So let’s give ’em some space.  How ’bout it?  (United States Fish and Wildlife Service image by Ryan Hagerty)

Piscivorous Waterfowl Visiting Lakes and Ponds

Heavy rains and snow melt have turned the main stem of the Susquehanna and its larger tributaries into a muddy torrent.  For fish-eating (piscivorous) ducks, the poor visibility in fast-flowing turbid waters forces them to seek better places to dive for food.  With man-made lakes and ponds throughout most of the region still ice-free, waterfowl are taking to these sources of open water until the rivers and streams recede and clear.

Common Mergansers
The Common Merganser is a species of diving duck with a primary winter range that, along the Atlantic Coast, reaches its southern extreme in the lower Susquehanna and Potomac watersheds.  Recently, many have left the main stem of the muddy rivers to congregate on waters with better visibility at some of the area’s larger man-made lakes.
Common Mergansers Feeding
Common Mergansers dive to locate and capture prey, primarily small fish.  During this century, their numbers have declined along the southern edge of their winter range, possibly due to birds remaining to the north on open water, particularly on the Great Lakes.  In the lower Susquehanna valley, some of these cavity-nesting ducks can now be found year-round in areas where heavy timber again provides breeding sites in riparian forests.  After nesting, females lead their young to wander widely along our many miles of larger rivers and streams to feed.
Several Common Mergansers Intimidating a Male with a Freshly Caught Fish
The behavior of these mergansers demonstrates the stiff competition for food that can result when predators are forced away from ideal habitat and become compressed into less favorable space.  On the river, piscivores can feed on the widespread abundance of small fish including different species of minnows, shiners, darters, and more.  In man-made lakes stocked for recreational anglers with sunfish, bass, and other predators (many of them non-native), small forage species are usually nonexistent.  As a result, fish-eating birds can catch larger fish, but are successful far less often.  Seen here are several mergansers resorting to intimidation in an effort to steal a young bass away from the male bird that just surfaced with it.  While being charged by the aggressors, he must quickly swallow his oversize catch or risk losing it.

With a hard freeze on the way, the fight for life will get even more desperate in the coming weeks.  Lakes will ice over and the struggle for food will intensify.  Fortunately for mergansers and other piscivorous waterfowl, high water on the Susquehanna is expected to recede and clarify, allowing them to return to their traditional environs.  Those with the most suitable skills and adaptations to survive until spring will have a chance to breed and pass their vigor on to a new generation of these amazing birds.

Photo of the Day

Wildflower Meadow Project underway at East Donegal Riverfront Park
Here’s something to look forward to in the new year.  The good citizens of East Donegal Township in Lancaster County have partnered with Alliance for the Chesapeake Bay to establish an extensive wildflower meadow on what had been a mowed field of turf grass at Riverside Park in the Susquehanna floodplain near Marietta.  As the photo shows, the lawn plants have been eliminated in preparation for seeding with a diverse assortment of native grasses and wildflowers to provide habitat for birds and pollinators including butterflies, bees, and other insects.  Once established, the meadow’s extensive vegetative growth will help reduce stormwater runoff by better infiltrating rainfall to recharge the aquifer.  During flood events, the plantings will provide soil stabilization and increase the ability of the acreage to uptake nutrients, thus reducing the negative impact of major storms on the quality of water in the river and in Chesapeake Bay.  Check the project’s progress by stopping by from time to time in 2024!

Shorebirds and Stormwater Retention Ponds

Your best bet for finding migrating shorebirds in the lower Susquehanna region is certainly a visit to a sandbar or mudflat in the river.  The Conejohela Flats off Washington Boro just south of Columbia is a renowned location.  Some man-made lakes including the one at Middle Creek Wildlife Management Area are purposely drawn down during the weeks of fall migration to provide exposed mud and silt for feeding and resting sandpipers and plovers.  But with the Susquehanna running high due to recent rains and the cost of fuel trending high as well, maybe you want to stay closer to home to do your observing.

Fortunately for us, migratory shorebirds will drop in on almost any biologically active pool of shallow water and mud that they happen to find.  This includes flooded portions of fields, construction sites, and especially stormwater retention basins.  We stopped by a new basin just west of Hershey, Pennsylvania, and found more than two dozen shorebirds feeding and loafing there.  We took each of these photographs from the sidewalk paralleling the south shore of the pool, thus never flushing or disturbing a single bird.

Stormwater retentrion basin.
Designed to prevent stream flooding and pollution, this recently installed stormwater retention basin along US 322 west of Hershey, Pennsylvania, has already attracted a variety of migrating plovers and sandpipers.
Killdeer
Killdeer stick close to exposed mud as they feed.
Least Sandpipers
Two of more than a dozen Least Sandpipers found busily feeding in the inch-deep water.
Lesser Yellowlegs
A Lesser Yellowlegs searching for small invertebrates.
Lesser Yellowlegs
Two Lesser Yellowlegs work out a disagreement.
Male Twelve-spotted Skimmers patrol the airspace above a pair of Least Sandpipers.
Male Twelve-spotted Skimmers patrol the airspace above a pair of Least Sandpipers. Dragonflies and other aquatic insects are quick to colonize the waters held in well-engineered retention basins.  Proper construction and establishment of a functioning food chain/web in these man-made wetlands prevents them from becoming merely temporary cesspools for breeding mosquitos.

So don’t just drive by those big puddles, stop and have a look.  You never know what you might find.

A Semipalmated Sandpiper (middle right) joins a flock of Least Sandpipers.
A Semipalmated Sandpiper (middle right) joins a flock of Least Sandpipers.
Pectoral Sandpipers (two birds in the center) are regular fall migrants on the Susquehanna at this time of year.
Pectoral Sandpipers (two birds in the center) are regular fall migrants on the Susquehanna at this time of year.  They are most frequently seen on gravel and sand bars adjacent to the river’s grassy islands, but unusually high water for this time of year prevents them from using this favored habitat.  As a result, you might be lucky enough to discover Pectoral Sandpipers on almost any mudflat in the area.
Two Pectoral Sandpipers and five smaller but very similar Least Sandpipers.
Two Pectoral Sandpipers and five smaller, but otherwise very similar, Least Sandpipers.
A Killdeer (right), a Semipalmated Plover (upper right), and a Least and Pectoral Sandpiper (left).
A Killdeer (right), a Semipalmated Plover (upper right), and Least and Pectoral Sandpipers (left).

Be on the Lookout: Black-bellied Whistling Ducks

Those mid-summer post-breeding wanders continue to delight birders throughout the Mid-Atlantic States.  One colorful denizen of ponds and wetlands that has yet to put in an appearance in the Lower Susquehanna River Watershed this year is the Black-bellied Whistling Duck.  You might remember this species from earlier posts describing the fortieth anniversary of your editor’s journey to the Lower Rio Grande Valley of Texas.  Like many other birds, the Black-bellied Whistling Duck has been extending its range north from Texas, Florida, and other states along the Gulf Coastal Plain.  Populations of these waterfowl are chiefly resident birds with some short-distance movement to find suitable habitat for feeding and nesting.  They are not usually migratory, so summertime wandering may be the mechanism for their discovery of new habitats advantageous for nesting in areas north of their current home.

Presently, at least two dozen Black-bellied Whistling Ducks are being seen regularly at a stormwater retention pond in a housing subdivision along Amalfi Drive west of Smyrna, Delaware.  This small population of avian tourists has spent at least two summers in the area.  Just yesterday, Black-bellied Whistling Ducks were seen and photographed about ten miles to the east at Bombay Hook National Wildlife Refuge.  Nine were counted there while 27 were being watched simultaneously at the Amalfi site.  Earlier this week, a single Black-bellied Whistling Duck visited the John Heinz National Wildlife Refuge in Philadelphia, indicating that the influx of these vagrants has transited the entire Delmarva Peninsula and entered Pennsylvania.  So while you’re out watching for those first southbound migrants of the year, be on the lookout for wayward wanderers too—wanderers like Black-bellied Whistling Ducks!

Black-bellied Whistling Ducks in a stormwater retention pond west of Smyrna, Delaware.
Black-bellied Whistling Ducks in a stormwater retention pond west of Smyrna, Delaware.
Black-bellied Whistling Ducks
Summertime exploration of new areas outside their resident turf may enable Black-bellied Whistling Ducks to find favorable habitats for extending their breeding range north.
Black-bellied Whistling Ducks
Black-bellied Whistling Ducks favor vegetated ponds, pools, and wetlands for feeding and nesting.
Black-bellied Whistling Ducks
Did you remember to go to the post office and buy a Federal Duck Stamp?   Your purchase helps provide habitat for Black-bellied Whistling Ducks and so many other magnificent birds.  And don’t forget, it’s your ticket for admission to our National Wildlife Refuges for an entire year!

A Few Plants with Wildlife Impact in June

Here’s a look at some native plants you can grow in your garden to really help wildlife in late spring and early summer.

The Larger Blue Flag (Iris versicolor) and Soft Rush (Juncus effusus) in flower in mid-June.
The showy bloom of a Larger Blue Flag (Iris versicolor) and the drooping inflorescence of Soft Rush (Juncus effusus).  These plants favor moist soils in wetlands and damp meadows where they form essential cover and feeding areas for insects, amphibians, and marsh birds.  Each is an excellent choice for helping to absorb nutrients in a rain garden or stream-side planting.  They do well in wet soil or shallow water along the edges of garden ponds too.
Smooth Shadbush
The fruits of Smooth Shadbush (Amelanchier laevis), also known as Allegheny Serviceberry, Smooth Serviceberry, or Smooth Juneberry, ripen in mid-June and are an irresistible treat for catbirds, robins, bluebirds, mockingbirds, and roving flocks of Cedar Waxwings.
Common Milkweed and Eastern Carpenter Bee
Also in mid-June, the fragrant blooms of Common Milkweed attract pollinators like Eastern Carpenter Bees,…
Common Milkweed and Honey Bee
…Honey Bees,…
Common Milkweed and Banded Hairstreak
…and butterflies including the Banded Hairstreak (Satyrium calanus).  In coming weeks, Monarch butterflies will find these Common Milkweed plants and begin laying their eggs on the leaves.  You can lend them a hand by planting milkweed species (Asclepias) in your garden.  Then watch the show as the eggs hatch and the caterpillars begin devouring the foliage.  Soon, they’ll pupate and, if you’re lucky, you’ll be able to watch an adult Monarch emerge from a chrysalis!

The Value of Water

Are you worried about your well running dry this summer?  Are you wondering if your public water supply is going to implement use restrictions in coming months?  If we do suddenly enter a wet spell again, are you concerned about losing valuable rainfall to flooding?  A sensible person should be curious about these issues, but here in the Lower Susquehanna River Watershed, we tend to take for granted the water we use on a daily basis.

This Wednesday, June 7,  you can learn more about the numerous measures we can take, both individually and as a community, to recharge our aquifers while at the same time improving water quality and wildlife habitat in and around our streams and rivers.  From 5:30 to 8:00 P.M., the Chiques Creek Watershed Alliance will be hosting its annual Watershed Expo at the Manheim Farm Show grounds adjacent to the Manheim Central High School in Lancaster County.  According to the organization’s web page, more than twenty organizations will be there with displays featuring conservation, aquatic wildlife, stream restoration, Honey Bees, and much more.  There will be games and custom-made fish-print t-shirts for the youngsters, plus music to relax by for those a little older.  Look for rain barrel painting and a rain barrel giveaway.  And you’ll like this—admission and ice cream are free.  Vendors including food trucks will be onsite preparing fare for sale.

And there’s much more.

To help recharge groundwater supplies, you can learn how to infiltrate stormwater from your downspouts, parking area, or driveway…

Urban Runoff
Does your local stream flood every time there’s a downpour, then sometimes dry up during the heat of summer?  Has this problem gotten worse over the years?  If so, you may be in big trouble during a drought.  Loss of base flow in a stream or river is a sure sign of depleted groundwater levels in at least a portion of its drainage basin.  Landowners, both public and private, in such a watershed need to start infiltrating stormwater into the ground instead of allowing it to become surface runoff.
Rain Garden Model
You can direct the stormwater from your downspout, parking area, or driveway into a rain garden to help recharge the aquifer that supplies your private or public well and nearby natural springs.  Displays including this model provided by Rapho Township show you how.

…there will be a tour of a comprehensive stream and floodplain rehabilitation project in Manheim Memorial Park adjacent to the fair grounds…

Legacy Sediments
Have you seen banks like these on your local stream?  On waterways throughout the Lower Susquehanna River Watershed, mill dams have trapped accumulations of sediments that eroded from farm fields prior to the implementation of soil conservation practices.  These legacy sediments channelize creeks and disconnect them from their now buried floodplains.  During storms, water that would have been absorbed by the floodplain is now displaced into areas of higher ground not historically inundated by a similar event.
Adjacent to the Manheim Farm Show grounds, the Chiques Creek Stream Restoration Project in Manheim Memorial Park has reconnected the waterway to its historic floodplain by removing a dam and the legacy sediments that accumulated behind it.
Legacy Sediments Removed
Chiques Creek in Manheim following removal of hundreds of truck loads of legacy sediments.  High water can again be absorbed by the wetlands and riparian forest of the floodplain surrounding this segment of stream.  There are no incised banks creating an unnatural channel or crumbling away to pollute downstream waters with nutrients and sediment.  Projects similar to this are critical to improving water quality in both the Susquehanna River and Chesapeake Bay.  Closer to home, they can help municipalities meet their stormwater management (MS4) requirements.
Bank-full Bench
Mark Metzler of Rettew Associates guides a tour of the Chiques Creek rehabilitation.  Here, cross vanes, stone structures that provide grade control along the stream’s course, were installed to gently steer the center of the channel away from existing structures.   Cross vanes manipulate the velocity of the creek’s flow across its breadth to dissipate potentially erosive energy and more precisely direct the deposition of gravel and sediment.

…and a highlight of the evening will be using an electrofishing apparatus to collect a sample of the fish now populating the rehabilitated segment of stream…

Electrofishing
Matt Kofroth, Lancaster County Conservation District Watershed Specialist, operates a backpack electrofishing apparatus while the netting crew prepares to capture the temporarily stunned specimens.  The catch is then brought to shore for identification and counting.

…so don’t miss it.  We can hardly wait to see you there!

The 2023 Watershed Expo is part of Lancaster Conservancy Water Week.

Forty Years Ago in the Lower Rio Grande Valley: Day Seven


Back in late May of 1983, four members of the Lancaster County Bird Club—Russ Markert, Harold Morrrin, Steve Santner, and your editor—embarked on an energetic trip to find, observe, and photograph birds in the Lower Rio Grande Valley of Texas.  What follows is a daily account of that two-week-long expedition.  Notes logged by Markert some four decades ago are quoted in italics.  The images are scans of 35 mm color slide photographs taken along the way by your editor.


DAY SEVEN—May 27, 1983

“Bentsen State Park”

“6 A.M. alarm rang.  After breakfast we walked an hour or more.  At 8:15 we phoned Father Tom for more information.  We next went back to Anzalduas County Park in hopes of seeing a Hook-billed Kite.  It is now 11:30 and NO luck.  Steve got his first lifer — Red-billed Pigeon.  We parked on a dirt dike and they went walking.  I took a nap.”

Based on new tips from Father Tom, we had back-tracked east along the Rio Grande to look for Hook-billed Kite, Red-billed Pigeon (Patagioenas flavirostris), and other species before continuing west toward Falcon Dam in coming days.  The pigeon was yet another specialty with a range that extends north from Central America into the subtropical riparian forests of the Lower Rio Grande Valley.

Anzalduas County Park is located along the Rio Grande at the Anzalduas Diversion Dam, part of a network of flood control projects initiated in the 1930s to reign in the “untamed river”.  Construction on this particular dam began in 1956 and was completed in 1960.  Operation of diversion and flood control dams on the Rio Grande has functionally eliminated stream meander along its present course, thus the delta that is the Lower Rio Grande Valley will cease to experience the morphological changes that create wetlands, resacas, and other natural features in the floodplain.  Thought to be excellent ideas at the time, most of these projects were based on a blurred vision of the connection between streams, their floodplains, and the watershed’s aquifer.  This condition has manifested itself as a blindness to the finite nature of water supplies, particular where consumption rates are still sharply rising while groundwater recharge is diminishing.

Anzalduas Diversion Dam and Interior Floodway System
The Anzalduas Diversion Dam redirects water from the Rio Grande to supply an irrigation canal on the Mexico side of the river.  In addition, the Anzalduas Reservoir supplies domestic water for Reynosa, Matamoros, and other towns south of the border.  To control flooding on the river downstream, a spillway on the north side of the reservoir created by the dam diverts high water into a seventy-mile-long dike-lined interior floodway that discharges the excess flow into the Gulf of Mexico.  A portion of the floodway utilizes the channel of the Arroyo Colorado through the Harlingen area.  On the map, irrigated lands are shaded green and urban space is yellow.  (International Boundary Water Commission-United States Section base image)

In addition to the Red-billed Pigeon, we found Brown-headed Cowbirds at Anzalduas County Park.  Flying over the adjacent reservoir/river there were Caspian Terns.  We identified some turtles too—Red-eared Sliders.

Back in 1983, we saw very few people in any of the parks or refuges along the Rio Grande.  From atop the flood control levee, I photographed this lone rider having a look around the interior floodway adjacent to Anzalduas County Park.  Today, this area is at times bustling with border patrol activity that includes the use of armored vehicles and mounted officers.  Shallow waters on the downstream side of the dam provide a busy crossing point for migrants and smugglers and the park itself was used as a migrant camp during the SARS-CoV-2 outbreak.  Border barrier design follows the levee as well as parts of the interior floodway itself.  As a result, many of these parks and refuges will be bisected or left entirely on the south side of the wall, a “no man’s land ” between it and the river.

“After my nap, I took pictures of the place and of the men coming back.  Then to the McAllen Sewage Ponds where we had some luck — Eared Grebe and others.”

The McAllen Sewage Ponds were like a little oasis for waterbirds.  Though not a specialty of the Lower Rio Grande Valley, the Eared Grebe (Podiceps nigricollis) was a western species we were happy to have seen.  A Gulf Coast species, Mottled Duck (Anas fulvigula), was another welcome find.  Other sightings included Least Grebe, 100 Ruddy Ducks, Northern Shoveler, Mallard, Black-bellied Whistling Duck, American Coot, Common Gallinule, Spotted Sandpiper, White-faced Ibis (Plegadis chihi), Black-necked Stilt, Franklin’s Gull, Least Tern (Sternula antillarum), Scissor-tailed Flycatcher, Great-tailed Grackle, and Bronzed Cowbird.

Swimming around in the McAllen Sewage Ponds was a Nutria (Myocastor coypus), also known as the Coypu, a mammal resembling a giant muskrat—remember, things really are bigger in Texas.

“Next to the Time Out  Camp Ground to check with a couple I met in February.  They had moved, their space was empty.  Back to Bentsen State Park.  On the way we bought a watermelon for supper’s dessert.  Rain almost all P.M.  Raining now 8:00 P.M.  Before supper we checked again for the Tropical Parula with no luck.  The watermelon was very good for dessert.”

Details received this morning from Father Tom suggested we check the area of the Bentsen Rio Grande Valley State Park campground near a large Spanish Moss-draped tree for the nesting Tropical Parulas.  I don’t recall what kind of tree it was, but the paved road circled the area surrounding it indicating that those who had designed the campground had purposely preserved this massive specimen as something unique.  Despite its prominence, no sights or sounds of the Tropical Parulas were found.  We reached the conclusion that we were a little late; they were gone for the year.  To soothe our sorrows, we ate watermelon—very refreshing!

Forty Years Ago in the Lower Rio Grande Valley: Day Four


Back in late May of 1983, four members of the Lancaster County Bird Club—Russ Markert, Harold Morrrin, Steve Santner, and your editor—embarked on an energetic trip to find, observe, and photograph birds in the Lower Rio Grande Valley of Texas.  What follows is a daily account of that two-week-long expedition.  Notes logged by Markert some four decades ago are quoted in italics.  The images are scans of 35 mm color slide photographs taken along the way by your editor.


DAY FOUR—May 24, 1983

“AOK Campground—South of Kingsville, Texas”

“Arose at 6:30 A.M. to the tune of Common Nighthawks.  After breakfast, we headed for Harlingen.  While driving south we saw six pairs of Black-bellied Whistling Ducks.  At Harlingen we phoned Father Tom, who is an expert birder for the area.”

As we drove south to Harlingen, much our 100-mile route was through the Laureles division of the King Ranch, the largest ranch in the United States.  It covers over 800,000 acres and is larger than the state of Rhode Island.  The road there was as straight as an arrow with wire fences on both sides and scrubland as far as the eye could see.  Things really are bigger in Texas.

Once in Harlingen, we did two things no one needs to do anymore:

      1.   Find a coin-operated telephone to place a call to Father Tom.
      2.   Ask Father Tom for the latest tips on the locations of rare and/or target birds.

Today, nearly everyone traveling such distances to find birds is carrying a cellular phone and many can use theirs to access internet sites and databases such as eBird to get current sighting information.  Back in 1983, Father Tom Pincelli was a dear friend to birders visiting the Lower Rio Grande Valley.  Few places had a person who was willing to answer the phone and field inquiries regarding the latest whereabouts of this or that bird.  To remain current, he also had to religiously (forgive me for the pun) collect sighting information from the observers with whom he had contact.  For locations elsewhere across the country, a birder in 1983 was happy just to have a phone number for a hotline with a tape-recorded message listing the unusual sightings for its covered region.  If you were lucky, the volunteer logging the sightings would be able to update the tape once a week.  For those who dialed his number, Father Tom provided an exceptionally personal experience.

Since 1983, Father Tom Pincelli, also known as “Father Bird”, has tirelessly promoted birding and conservation throughout the Lower Rio Grande Valley.  His efforts have included hosting a P.B.S. television program and writing columns for local newspapers.  He has been instrumental in developing the annual Rio Grande Valley Birding Festival.  The public sentiment he has generated for the birding paradise that is the Lower Rio Grande Valley has helped facilitate the acquisition and/or protection of many key parcels of land in the region.

“After receiving information on locations of Tropical Parula, Ferruginous Pygmy Owl, Hook-billed Kite, Brown Jay, and Clay-colored Robin, we went on to check out the Brownsville Airport where we will meet Harold and Steve Thursday noon.”

If we were going to see these five species in the American Birding Association listing area, then we would have to see them in the Lower Rio Grande Valley.  All five were target birds for each of us, including Harold who had few other possibilities for new species on the trip.  Father Tom provided us with tips for finding each.

I noticed as we began moving around Harlingen and Brownsville that Russ was swiftly getting his bearings—he had been here before and was starting to remember where things were.  His ability to navigate his way around allowed us to keep moving and see a lot in a short time.

In Harlingen, we easily found Mourning Doves and the non-native Rock Pigeons, species we see regularly in Pennsylvania.  We became more enthusiastic about doves and pigeons soon after when we saw the first of the several other species native to south Texas, the diminutive Inca Dove (Columbina inca), also known as the Mexican Dove.

“Next, to the Brownsville Dump to see the White-necked Ravens — Then to Mrs. Benn’s in Brownsville for the Buff-bellied Hummingbird.  Both lifers for Larry.”

For birders wanting to see a White-necked Raven in the Lower Rio Grande Valley, the Brownsville Dump was the place to go.  With very little effort—excluding a trip of nearly 2,000 miles to get there—we found them.  Today, birders still go to the Brownsville Dump to find White-necked Ravens, though the dump is now called the Brownsville Landfill and the bird is known as the Chihuahuan Raven (Corvus cryptoleucus).

Mrs. Benn’s home was in a verdant residential neighborhood in Brownsville.  She welcomed birders to come and see the Buff-bellied Hummingbirds that visited her feeder filled with sugar water.  I don’t recall whether or not she kept a guest book for visitors to sign, but if she did, it would have included hundreds—maybe thousands—of names of people from all over North America who came to her garden to get a look at a Buff-bellied Hummingbird.  After arriving, we waited a short time and sure enough, we watched a Buff-bellied Hummingbird (Amazilia yucatanensis) sipping Mrs. Benn’s home-brewed nectar from her glass feeder.  This emerald hummingbird is primarily a Mexican species with a breeding range that extends north into the Lower Rio Grande Valley of Texas.  When not breeding, a few will wander north and east along the Gulf Coastal Plain as far as Florida.

Other finds at Mrs Benn’s included White-winged Dove (Zenaida asiatica), Ash-throated Flycatcher (Myiarchus cinerascens), Brown-crested Flycatcher (Myiarchus tyrannulus), and Black-crested Titmouse (Baeolophus atricristatus), a species also known as Mexican Titmouse.

White-winged Dove
We identified this White-winged Dove at Mrs. Benn’s house in Brownsville.
Green Anole
In Mrs. Benn’s lush subtropical garden beneath a canopy of tall trees we found this male Green Anole (Anolis carolinensis) displaying its red throat patch.  (Vintage 35 mm image)

The Lower Rio Grande Valley from Rio Grande City east to the Gulf of Mexico is actually the river’s outflow delta.  At least six historic channels have been delineated in Texas on the north side of the river’s present-day course.  An equal number may exist south of the border in Mexico.  Hundreds of oxbow lakes known as “resacas” mark the paths of the former channels through the delta.  Many resacas are the centerpieces of parks, wildlife refuges, and housing developments.  Still others are barely detectable after being buried in silt deposits left by the meandering river.  Channelization, land disturbances related to agriculture, and a boom in urbanization throughout the valley have disconnected many of the most recently formed resacas from the river’s floodplain, preventing them from absorbing the impact of high-water events.  These alterations to natural morphology can severely aggravate flooding and water pollution problems.

The Lower Rio Grande Valley
The Lower Rio Grande Valley is the site of a boom in urbanization.  Undeveloped private holdings and government lands including numerous parks and refuges provide sanctuary for some of the valley’s unique wildlife.  The parcels colored dark blue on the map are units of the Lower Rio Grande Valley National Wildlife Refuge.  (United States Fish and Wildlife Service base image)

“On to Santa Ana National Wildlife Refuge.  We walked to Pintail Lake and saw 6 Black-bellied Whistling Ducks and 2 Mississippi Kites and 1 Pied-billed Grebe.  We drove the route thru the park with great results—Anhingas, Least Grebe, and more Black-bellied Whistling Ducks.

Santa Ana National Wildlife Refuge on the Rio Grande is not only a birder’s mecca, 300 species of butterflies have been identified there.  That’s half the species known to occur in the United States!  Its subtropical riparian forest and resaca lakes provide habitat for hundreds of migratory and resident bird species including many Central and South American species that reach the northern limit of their range in the Lower Rio Grande Valley.  Two endangered cats occur in the park—the Ocelot (Leopardus pardalis) and the Jaguarundi  (Herpailurus yagouaroundi).

Ocelot
In the Lower Rio Grande Valley, the secretive Ocelot, like the Jaguarundi, is at the northern limit of its eastern range. Time will tell how urban development including construction of the border wall will impact the distribution and survival of these and other terrestrial species there.  (A modern digital image)
Jaguarundi
Jaguarundi.  (United States Fish and Wildlife Service image)

We saw no cats at Santa Ana, but did quite well with the birds.  Our list included the species listed above plus Cattle Egret (Bubulcus ibis); Louisiana Heron, now known as Tricolored Heron (Egretta tricolor); Plain Chachalacas; Purple Gallinule; Common Gallinule (Gallinula galeata); American Coot; Killdeer; Greater Yellowlegs; the coastal Laughing Gull (Leucophaeus atricilla); and its close relative of the central flyway and continental interior, the Franklin’s Gull (Leucophaeus pipixcan).  Others finds were White-winged Dove, Mourning Dove, Inca Dove, Yellow-billed Cuckoo, Golden-fronted Woodpecker, Ladder-backed Woodpecker (Dryobates scalaris), Brown-crested Flycatcher, Altamira Oriole, Great-tailed Grackle, and House Sparrow.  A real standout was the colorful Green Jay (Cyanocorax luxosus), yet another tropical Central American species found north only as far as the Lower Rio Grande Valley.

Mississippi Kite
During spring (April-May) and fall (August-September), Mississippi Kites migrate by the thousands through the skies of the Lower Rio Grande Valley.  Both Santa Ana and nearby Bentsen-Rio Grande State Park have hosted formal hawk counts in recent years.  (Vintage 35 mm image)
Black-necked Stilt
A Black-necked Stilt at Santa Ana N.W.R.  (Vintage 35 mm image)
Least Grebe
A Least Grebe (Tachybaptus dominicus) with young in a man-made canal that mimics flooded resaca habitat at Santa Ana National Wildlife Refuge.  (Vintage 35 mm image)
Black-bellied Whistling Ducks at Santa Ana National Wildlife Refuge
Black-bellied Whistling Ducks take off from a pond at Santa Ana National Wildlife Refuge.  (Vintage 35 mm image)
Altamira Oriole
The spectacular colors of Altamira Orioles (Icterus gularis) dazzled us every time we saw them.  This was my first, seen soon after arriving at Santa Ana N.W.R. where the checklist still had the species listed under its former name, Lichtenstein’s Oriole. The Altamira Oriole ranges north of Mexico only into the Lower Rio Grande Valley.  (Vintage 35 mm image)

“We were unlucky not to find a campground at McAllen, so we went on to Bentsen State Park where we got a camp spot.  After a sauerkraut supper, we birded till dark, then showered and wrote up the log.  Very hot today.”

Bentsen-Rio Grande Valley State Park, like the Santa Ana National Wildlife Refuge, is located along the Rio Grande river and features dense subtropical riparian forest that grows in the naturally-deposited silt levees of the floodplain surrounding several lake-like oxbow resacas.  Montezuma Bald Cypress (Taxodium mucronatum) is a native specialty found there but nowhere north of the Lower Rio Grande Valley.  During our visit, we marveled at the epiphyte Spanish Moss (Tillandsia usneoides) adorning many of the more massive trees in the park.  Willows lined much of the river shoreline.

Over time, flood control projects such as man-made dams, drainage ditches, and levees have impaired stormwater capture and aquifer recharge in the floodplain.  These alterations to watershed hydrology have resulted in drier soils in many sections of the Lower Rio Grande Valley’s riparian forests.  Where drier conditions persist, xeric (dry soil) scrubland plants are slowly overtaking the moisture-dependent species.  As a result, the park’s woodlands are composed of trees with a variety of microclimatic requirements—Anaqua (Ehretia anacua), Cedar Elm (Ulmus crassifolia), Texas Ebony (Ebenopsis ebano), hackberry, mesquite, Mexican Ash (Fraxinus berlandieriana), retama, and tepeguaje are the principle species.  The park’s subtropical Texas Wild Olive (Cordia boissieri) grows in the wild nowhere north of the Lower Rio Grande Valley.

While a majority of birders visiting Benten-Rio Grande State Park come to see the more tropical specialties of the riparian woods, searching the brushy habitat of the park’s scrubland can afford one the opportunity to see species typical of the southwestern United States and deserts of Mexico.  This scrubland of the Lower Rio Grande Valley is part of the Tamaulipan Mezquital ecoregion, an area of xeric (dry soil) shrublands and deserts that extends northwest from the delta through most of south Texas and into the bordering provinces of northeastern Mexico.

Our campsite was located in prime birding habitat.  We were a short walk away from one of the park’s flooded oxbow resacas and vegetation was thick along the roadsides.  It was no surprise that the place abounded with birds.  An evening stroll yielded Plain Chachalaca, White-winged Dove, Mourning Dove, White-fronted Dove, Golden-fronted Woodpecker, Brown-crested Flycatcher, Green Jay, Altamira Oriole, Great-tailed Grackle, and Bronzed Cowbird (Molothrus aeneus).  At nightfall, we listened to the calls of an Eastern Screech Owl (Megascops asio), Common Nighthawks, and Common Pauraque (Nyctidromus albicollis), a nightjar of Central and South America that nests only as far north as the Lower Rio Grande Valley.  The Common Pauraque is the tropical counterpart of the Eastern Whip-poor-will, a Neotropical migrant that nests in scattered forest locations throughout eastern North America.

A Plain Chachalaca at Bentsen-Rio Grande Valley State Park.
The Plain Chachalaca (Ortalis vetula), a pheasant-like wildfowl of the dense riparian forest and scrubland at Bentsen-Rio Grande Valley State Park.  (Vintage 35 mm image)
Plain Chachalacas
Seldom did we see a Plain Chachalaca alone, there were always others nearby.  (Vintage 35 mm image)
White-fronted Dove
Like the chachalacas, this White-fronted Dove was attracted to some birdseed scattered on a big log behind our campsite.  This species is now known as White-tipped Dove (Leptotila verreauxi) and is at the northern tip of its range in the Lower Rio Grande Valley.

I would note that we saw no “snowbirds”—long-term vacationers from the northern states and Canada who fill the park through the cooler months of fall, winter, and spring.  They were gone for the summer.  But for a few other friendly folks, we had the entire campground to ourselves for the duration of our stay.

How Much Rainwater Runs Off Your Roof During a Storm?

During the spare time you have on a rainy day like today, you may have asked yourself, “Just how much water do people collect with those rain barrels they have attached to their downspouts?”  That’s a good question.  Let’s do a little math to figure it out.

First, we need to determine the area of the roof in square feet.  There’s no need to climb up there and measure angles, etc.  After all, we’re not ordering shingles—we’re trying to figure out the surface area upon which rain will fall vertically and be collected.  For our estimate, knowing the footprint of the building under roof will suffice.  We’ll use a very common footprint as an example—1,200 square feet.

40′ x 30′ = 1,200 sq. ft.

By dividing the area of the roof by 12, we can calculate the volume of water in cubic feet that is drained by the spouting for each inch of rainfall…

1,200 ÷ 12 = 100 cu. ft. per inch of rainfall

 

Next, we multiply the volume of water in cubic feet by 7.48 to convert it to gallons per inch of rainfall…

100 x 7.48 = 748 gallons per inch of rainfall

 

That’s a lot of water.  Just one inch of rain could easily fill more than a single rain barrel on a downspout.  Many homemade rain barrels are fabricated using recycled 55-gallon drums.  Commercially manufactured ones are usually smaller.  Therefore, we can safely say that in the case of a building with a footprint of 1,200 square feet, an array of at least 14 rain barrels is required to collect and save just one inch of rainfall.  Wow!

Why send that roof water down the street, down the drain, down the creek, or into the neighbors property?  Wouldn’t it be better to catch it for use around the garden?  At the very least, shouldn’t we be infiltrating all the water we can into the ground to recharge the aquifer?  Why contribute to flooding when you and I are gonna need that water some day?   Remember, the ocean doesn’t need the excess runoff—it’s already full.

Thank You Volunteers!

As your editor here at susquehannawildlife.net, I’d like to take a moment to thank all the volunteers who gave of their valuable time today to pick up litter, plant trees, and take other civic actions in observance of Earth Day.  Your hard work has not gone unnoticed.

Special appreciation goes out to the anonymous crew that worked its way through the area surrounding our headquarters to pick up the trash on the rental and business properties in the neighborhood.  My personal thanks is extended to you.

If you’ve never lived in an urban or downtown area, you’re probably unaware of the environmental damage and decline in the quality of life that occurs when “investors” start buying up the houses near you.  The first things to go are the trees and shrubs—less maintenance that way.  Next, more paving is installed to park more cars.  That leads to more stormwater runoff, so look out if you happen to live downstream.  Then the long-term neglect begins.  The absentee “slumlords” show up only to collect the rent, if at all.  Unless the tenants are conscientious enough to do a little sweeping, the rubbish begins to accumulate.  It’s a funny thing, when there’s a bunch of junk lying around, people feel compelled to start dumping more.  So to you volunteers who today helped nip the problem in the bud with your efforts, I want you to know that you’re the best!  As for you greedy landlords—shame on you.

Photo of the Day

Legacy Sediment Removal and Floodplain Restoration
This stream restoration project is currently underway along a one-mile-long segment of Lancaster Conservancy lands along Conewago Creek.  The mountain of dirt is one of several stockpiles of legacy sediments removed to reestablish the floodplain’s historic geomorphology.  After eroding from cropland during the years prior to soil conservation, legacy sediments accumulated behind mill dams on waterways throughout the lower Susquehanna watershed.  After removal of the dams, creeks were left trapped within the sediment-choked bottomlands, incising steep muddy banks as they cut a new path through the former mill ponds.  Excavating legacy sediments from these sites eliminates creek banks and allows floodwaters to again spill directly into wetlands along the stream course.  With floodplain and wetland functions restored, nutrients are sequestered, high water is infiltrated to recharge aquifers, sediment loads from collapsing banks are eliminated, and much-needed habitat is created for native plants and animals.

To learn more about this project and others, you’ll want to check out the Landstudies website.

Take a Look at My Mussels

At this very moment, your editor is comfortably numb and is, if everything is going according to plans, again having a snake run through the plumbing in his body’s most important muscle.  It thus occurs to him how strange it is that with muscles as run down and faulty as his, people at one time asked him to come speak about and display his marvelous mussels.  And some, believe it or not, actually took interest in such a thing.  If the reader finds this odd, he or she would not be alone.  But the peculiarities don’t stop there.  The reader may find further bewilderment after being informed that the editor’s mussels are now in the collection of a regional museum where they are preserved for study by qualified persons with scientific proclivities.  All of this show and tell was for just one purpose—to raise appreciation and sentiment for our mussels, so that they might be protected.

Click on the “Freshwater Mussels and Clams” tab at the top of this page to see the editor’s mussels, and many others as well.  Then maybe you too will want to flex your muscles for our mussels.  They really do need, and deserve, our help.

We’ll be back soon.

Monarch an Endangered Species: What You Can Do Right Now

This month, the International Union for Conservation of Nature (I.U.C.N.) added the Migratory Monarch Butterfly (Danaus plexippus plexippus) to its “Red List of Threatened Species”, classifying it as endangered.  Perhaps there is no better time than the present to have a look at the virtues of replacing areas of mowed and manicured grass with a wildflower garden or meadow that provides essential breeding and feeding habitat for Monarchs and hundreds of other species of animals.

Monarch on Common Milkweed Flower Cluster
A recently arrived Monarch visits a cluster of fragrant Common Milkweed flowers in the garden at the susquehannawildlife.net headquarters.  Milkweeds included among a wide variety of plants in a garden or meadow habitat can help local populations of Monarchs increase their numbers before the autumn flights to wintering grounds commence in the fall.  Female Monarchs lay their eggs on milkweed leaves, then, after hatching, the larvae (caterpillars) feed on them before pupating.

If you’re not quite sure about finally breaking the ties that bind you to the cult of lawn manicuring, then compare the attributes of a parcel maintained as mowed grass with those of a space planted as a wildflower garden or meadow.  In our example we’ve mixed native warm season grasses with the wildflowers and thrown in a couple of Eastern Red Cedars to create a more authentic early successional habitat.

Comparison of Mowed Grass to Wildflower Meadow
* Particularly when native warm-season grasses are included (root depth 6′-8′)

Still not ready to take the leap.  Think about this: once established, the wildflower planting can be maintained without the use of herbicides or insecticides.  There’ll be no pesticide residues leaching into the soil or running off during downpours.  Yes friends, it doesn’t matter whether you’re using a private well or a community system, a wildflower meadow is an asset to your water supply.  Not only is it free of man-made chemicals, but it also provides stormwater retention to recharge the aquifer by holding precipitation on site and guiding it into the ground.  Mowed grass on the other hand, particularly when situated on steep slopes or when the ground is frozen or dry, does little to stop or slow the sheet runoff that floods and pollutes streams during heavy rains.

What if I told you that for less than fifty bucks, you could start a wildflower garden covering 1,000 square feet of space?  That’s a nice plot 25′ x 40′ or a strip 10′ wide and 100′ long along a driveway, field margin, roadside, property line, swale, or stream.  All you need to do is cast seed evenly across bare soil in a sunny location and you’ll soon have a spectacular wildflower garden.  Here at the susquehannawildllife.net headquarters we don’t have that much space, so we just cast the seed along the margins of the driveway and around established trees and shrubs.  Look what we get for pennies a plant…

Wildflower Garden
Some of the wildflowers and warm-season grasses grown from scattered seed in the susquehannawildlife.net headquarters garden.

Here’s a closer look…

Lance-leaved Coreopsis
Lance-leaved Coreopsis (Coreopsis lanceolata), a perennial.
Black-eyed Susan
Black-eyed Susan, a biennial or short-lived perennial.
Black-eyed Susan "Gloriosa Daisy"
“Gloriosa Daisy”, a variety of Black-eyed Susan, a biennial or short-lived perennial.
Purple Coneflower
Purple Coneflower, an excellent perennial for pollinators.  The ripe seeds provide food for American Goldfinches.
Common Sunflower
A short variety of Common Sunflower, an annual and a source of free bird seed.
Common Sunflower
Another short variety of Common Sunflower, an annual.

All this and best of all, we never need to mow.

Around the garden, we’ve used a northeast wildflower mix from American Meadows.  It’s a blend of annuals and perennials that’s easy to grow.  On their website, you’ll find seeds for individual species as well as mixes and instructions for planting and maintaining your wildflower garden.  They even have a mix specifically formulated for hummingbirds and butterflies.

Annuals in bloom
When planted in spring and early summer, annuals included in a wildflower mix will provide vibrant color during the first year.  Many varieties will self-seed to supplement the display provided by biennials and perennials in subsequent years.
Wildflower Seed Mix
A northeast wildflower mix from American Meadows.  There are no fillers.  One pound of pure live seed easily plants 1,000 square feet.

Nothing does more to promote the spread and abundance of non-native plants, including invasive species, than repetitive mowing.  One of the big advantages of planting a wildflower garden or meadow is the opportunity to promote the growth of a community of diverse native plants on your property.  A single mowing is done only during the dormant season to reseed annuals and to maintain the meadow in an early successional stage—preventing reversion to forest.

For wildflower mixes containing native species, including ecotypes from locations in and near the Lower Susquehanna River Watershed, nobody beats Ernst Conservation Seeds of Meadville, Pennsylvania.  Their selection of grass and wildflower seed mixes could keep you planting new projects for a lifetime.  They craft blends for specific regions, states, physiographic provinces, habitats, soils, and uses.  Check out these examples of some of the scores of mixes offered at Ernst Conservation Seeds

      • Pipeline Mixes
      • Pasture, Grazing, and Hay Mixes
      • Cover Crops
      • Pondside Mixes
      • Warm-season Grass Mixes
      • Retention Basin Mixes
      • Wildlife Mixes
      • Pollinator Mixes
      • Wetland Mixes
      • Floodplain and Riparian Buffer Mixes
      • Rain Garden Mixes
      • Steep Slope Mixes
      • Solar Farm Mixes
      • Strip Mine Reclamation Mixes

We’ve used their “Showy Northeast Native Wildflower and Grass Mix” on streambank renewal projects with great success.  For Monarchs, we really recommend the “Butterfly and Hummingbird Garden Mix”.  It includes many of the species pictured above plus “Fort Indiantown Gap” Little Bluestem, a warm-season grass native to Lebanon County, Pennsylvania, and milkweeds (Asclepias), which are not included in their northeast native wildflower blends.  More than a dozen of the flowers and grasses currently included in this mix are derived from Pennsylvania ecotypes, so you can expect them to thrive in the Lower Susquehanna River Watershed.

Swamp Milkweed
Swamp Milkweed, a perennial species, is included in the Ernst Seed “Butterfly and Hummingbird Garden Mix”.  It is a favorite of female Monarchs seeking a location to deposit eggs.
Monarch Caterpillar feeding on Swamp Milkweed
A Monarch larva (caterpillar) feeding on Swamp Milkweed.
Butterfly Weed
Butterfly Weed (Asclepias tuberosa) is included in the Ernst Seed “Butterfly and Hummingbird Garden Mix”.  This perennial is also known as Butterfly Milkweed.
Tiger Swallowtails visiting Butterfly Weed
Eastern Tiger Swallowtails are among the dozens of species of pollinators that will visit Butterfly Weed.

In addition to the milkweeds, you’ll find these attractive plants included in Ernst Conservation Seed’s “Butterfly and Hummingbird Garden Mix”, as well as in some of their other blends.

Wild Bergamot
The perennial Wild Bergamot, also known as Bee Balm, is an excellent pollinator plant, and the tubular flowers are a favorite of hummingbirds.
Oxeye
Oxeye is adorned with showy clusters of sunflower-like blooms in mid-summer.  It is a perennial plant.
Plains Coreopsis
Plains Coreopsis (Coreopsis tinctoria), also known as Plains Tickseed, is a versatile annual that can survive occasional flooding as well as drought.
Gray-headed Coneflower
Gray-headed Coneflower (Ratibida pinnata), a tall perennial, is spectacular during its long flowering season.
Monarch on goldenrod.
Goldenrods are a favorite nectar plant for migrating Monarchs in autumn.  They seldom need to be sown into a wildflower garden; the seeds of local species usually arrive on the wind.  They are included in the “Butterfly and Hummingbird Garden Mix” from Ernst Conservation Seeds in low dose, just in case the wind doesn’t bring anything your way.
Partridge Pea
Is something missing from your seed mix?  You can purchase individual species from the selections available at American Meadows and Ernst Conservation Seeds.  Partridge Pea is a good native annual to add.  It is a host plant for the Cloudless Sulphur butterfly and hummingbirds will often visit the flowers.  It does really well in sandy soils.
Indiangrass in flower.
Indiangrass is a warm-season species that makes a great addition to any wildflower meadow mix.  Its deep roots make it resistant to drought and ideal for preventing erosion.

Why not give the Monarchs and other wildlife living around you a little help?  Plant a wildflower garden or meadow.  It’s so easy, a child can do it.

Planting a riparian buffer with wildflowers and warm-season grasses
Volunteers sow a riparian buffer on a recontoured stream bank using wildflower and warm-season grass seed blended uniformly with sand.  By casting the sand/seed mixture evenly over the planting site, participants can visually assure that seed has been distributed according to the space calculations.
Riparian Buffer of wildflowers
The same seeded site less than four months later.
Monarch Pupa
A Monarch pupa from which the adult butterfly will emerge.

Photo of the Day

Buttonbush flower cluster
Is it the latest image from NASA’s new Webb Space Telescope?  Nope, it’s the globular flower cluster of the Buttonbush, a native shrub species found throughout the Lower Susquehanna River Watershed.  Buttonbush thrives in wet soil and seldom grows taller than 10 feet in height.  Try it along stream banks, in stormwater retention basins, and in rain gardens fed by surface runoff or the outflow from your downspouts.

Three Mile Island and Agnes: Fifty Years Later

Fifty years ago this week, the remnants of Hurricane Agnes drifted north through the Susquehanna River basin as a tropical storm and saturated the entire watershed with wave after wave of torrential rains.  The storm caused catastrophic flooding along the river’s main stem and along many major tributaries.  The nuclear power station at Three Mile Island, then under construction, received its first major flood.  Here are some photos taken during the climax of that flood on June 24, 1972.  The river stage as measured just upstream of Three Mile Island at the Harrisburg gauge crested at 33.27 feet, more than 10 feet above flood stage and almost 30 feet higher than the stage at present.  At Three Mile Island and Conewago Falls, the river was receiving additional flow from the raging Swatara Creek, which drains much of the anthracite coal region of eastern Schuylkill County—where rainfall from Agnes may have been the heaviest.

Three Mile Island flooding from Agnes 1972.
1972-  From the river’s east shore at the mouth of Conewago Creek, Three Mile Island’s “south bridge” crosses the Susquehanna along the upstream edge of Conewago Falls.  The flood crested just after covering the roadway on the span.  Floating debris including trees, sections of buildings, steel drums, and rubbish began accumulating against the railings on the bridge’s upstream side, leading observers to speculate that the span would fail.  When a very large fuel tank, thousands of gallons in capacity, was seen approaching, many thought it would be the straw that would break the camel’s back.  It wasn’t, but the crashing sounds it made as it struck the bridge then turned and began rolling against the rails was unforgettable.  (Larry L. Coble, Sr. image)
Three Mile Island flooding from Agnes 1972.
1972-  In this close-up of the preceding photo, the aforementioned piles of junk can be seen along the upstream side of the bridge (behind the sign on the right).  The fuel tank struck and was rolling on the far side of this pile.  (Larry L. Coble, Sr. image)
2022-  Three Mile Island’s “south bridge” as it appeared this morning, June 24,2022.
Three Mile Island flooding from Agnes 1972.
1972-  The railroad along the east shore at Three Mile Island’s “south bridge” was inundated by rising water.  This flooded automobile was one of many found in the vicinity.  Some of these vehicles were overtaken by rising water while parked, others were stranded while being driven, and still others floated in from points unknown.  (Larry L. Coble, Sr. image)
2022-  A modern view of the same location.
Three Mile Island flooding from Agnes 1972.
1972-  At the north end of Three Mile Island, construction on Unit 1 was halted.  The completed cooling towers can be seen to the right and the round reactor building can be seen behind the generator building to the left.  The railroad grade along the river’s eastern shore opposite the north end of the island was elevated enough for this train to stop and shelter there for the duration of the flood.  (Larry L. Coble, Sr. image)
2022-  Three Mile Island Unit 1 as it appears today: shut down, defueled, and in the process of deconstruction.
Three Mile Island flooding from Agnes 1972.
1972-  In March of 1979, the world would come to know of Three Mile Island Unit 2.  During Agnes in June of 1972, flood waters surrounding the plant resulted in a delay of its construction.  In the foreground, note the boxcar from the now defunct Penn Central Railroad.  (Larry L. Coble, Sr. image)
2022-  A current look at T.M.I. Unit 2, shut down since the accident and partial meltdown in 1979.

Pictures capture just a portion of the experience of witnessing a massive flood.  Sometimes the sounds and smells of the muddy torrents tell us more than photographs can show.

Aside from the booming noise of the fuel tank banging along the rails of the south bridge, there was the persistent roar of floodwaters, at the rate of hundreds of thousands of cubic feet per second, tumbling through Conewago Falls on the downstream side of the island.   The sound of the rapids during a flood can at times carry for more than two miles.  It’s a sound that has accompanied the thousands of floods that have shaped the falls and its unique diabase “pothole rocks” using abrasives that are suspended in silty waters after being eroded from rock formations in the hundreds of square miles of drainage basin upstream.  This natural process, the weathering of rock and the deposition of the material closer to the coast, has been the prevailing geologic cycle in what we now call the Lower Susquehanna River Watershed since the end of the Triassic Period, more than two hundred million years ago.

More than the sights and sounds, it was the smell of the Agnes flood that warned witnesses of the dangers of the non-natural, man-made contamination—the pollution—in the waters then flowing down the Susquehanna.

Because they float, gasoline and other fuels leaked from flooded vehicles, storage tanks, and containers were most apparent.  The odor of their vapors was widespread along not only along the main stem of the river, but along most of the tributaries that at any point along their course passed through human habitations.

Blended with the strong smell of petroleum was the stink of untreated excrement.  Flooded treatment plants, collection systems overwhelmed by stormwater, and inundated septic systems all discharged raw sewage into the river and many of its tributaries.  This untreated wastewater, combined with ammoniated manure and other farm runoff, gave a damaging nutrient shock to the river and Chesapeake Bay.

Adding to the repugnant aroma of the flood was a mix of chemicals, some percolated from storage sites along watercourses, and yet others leaking from steel drums seen floating in the river.  During the decades following World War II, stacks and stacks of drums, some empty, some containing material that is very dangerous, were routinely stored in floodplains at businesses and industrial sites throughout the Susquehanna basin.  Many were lifted up and washed away during the record-breaking Agnes flood.  Still others were “allowed” to be carried away by the malicious pigs who see a flooding stream as an opportunity to “get rid of stuff”.  Few of these drums were ever recovered, and hundreds were stranded along the shoreline and in the woods and wetlands of the floodplain below Conewago Falls.  There, they rusted away during the next three decades, some leaking their contents into the surrounding soils and waters.  Today, there is little visible trace of any.

During the summer of ’72, the waters surrounding Three Mile Island were probably viler and more polluted than at any other time during the existence of the nuclear generating station there.  And little, if any of that pollution originated at the facility itself.

The Susquehanna’s floodplain and water quality issues that had been stashed in the corner, hidden out back, and swept under the rug for years were flushed out by Agnes, and she left them stuck in the stinking mud.

Pick Up and Get Out of the Floodplain

The remnants of Hurricane Ida are on their way to the Lower Susquehanna River Watershed.  After making landfall in Louisiana as a category 4 storm, Ida is on track to bring heavy rain to the Mid-Atlantic States beginning tonight.

Tropical Depression Ida moving slowly toward the northeast.   (NOAA/GOES image)

Rainfall totals are anticipated to be sufficient to cause flooding in the lower Susquehanna basin.  As much as six to ten inches of precipitation could fall in parts of the area on Wednesday.

Rainfall forecasts from the National Hurricane Center.  (NOAA/National Hurricane Center image)

Now would be a good time to get all your valuables and junk out of the floodways and floodplains.  Move your cars, trucks, S.U.V.s, trailers, and boats to higher ground.  Clear out the trash cans, playground equipment, picnic tables, and lawn furniture too.  Get it all to higher ground.  Don’t be the slob who uses a flood as a chance to get rid of tires and other rubbish by letting it just wash away.

Vehicles parked atop fill that has been dumped into a stream’s floodplain are in double trouble.  Fill displaces water and exasperates flooding instead of providing refuge from it.  Better move these cars, trucks, and trailers to higher ground, posthaste.

Flooding not only has economic and public safety impacts, it is a source of enormous amounts of pollution.  Chemical spills from inundated homes, businesses, and vehicles combine with nutrient and sediment runoff from eroding fields to create a filthy brown torrent that rushes down stream courses and into the Susquehanna.  Failed and flooded sewage facilities, both municipal and private, not only pollute the water, but give it that foul odor familiar to those who visit the shores of the river after a major storm.  And of course there is the garbage.  The tons and tons of waste that people discard carelessly that, during a flood event, finds its way ever closer to the Susquehanna, then the Chesapeake, and finally the Atlantic.  It’s a disgraceful legacy.

Now is your chance to do something about it.  Go out right now and pick up the trash along the curb, in the street, and on the sidewalk and lawn—before it gets swept into your nearby stormwater inlet or stream.  It’s easy to do, just bend and stoop.  While you’re at it, clean up the driveway and parking lot too.

Secure your trash and pick up litter before it finds its way into the storm sewer system and eventually your local stream.  It’ll take just a minute.
This is how straws and other plastics find their way to the ocean and the marine animals living there, so pick that stuff up!  Did you know that keeping stormwater inlets clean can prevent street flooding and its destructive extension into the cellars of nearby homes and businesses?
There’s another straw.  Pick it and the rest of that junk up now, before the storm.  Don’t wait for your local municipality or the Boy Scouts to do it.  You do it, even if it’s not your trash.

We’ll be checking to see how you did.

And remember, flood plains are for flooding, so get out of the floodplain and stay out.

Put Up the White Flag

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.