Astronomy – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

August 20, 2024November 22, 2024

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.

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.

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.

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.

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 Streams and Rivers — 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.

Gaining Stream — 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)

Losing Stream — 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)

Disconnected Stream — 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.

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.

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.

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.

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 Sun — 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)

Solar (Shortwave) Radiation — 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 — 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).

West Conewago Creek 90 Days — 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.

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 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.

Upper Conewago Creek (East) Watershed — 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.

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.

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)

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.

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.

You Don't Have Time to Mow, We've Got 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!

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)

April 9, 2024April 10, 2024

Solar Eclipse of 2024

It was dubbed the “Great Solar Eclipse”, the Great North American Eclipse”, and several other lofty names, but in the lower Susquehanna valley, where about 92% of totality was anticipated, the big show was nearly eclipsed by cloud cover. With last week’s rains raising the waters of the river and inundating the moonscape of the Pothole Rocks at Conewago Falls, we didn’t have the option of repeating our eclipse observations of August, 2017, by going there to view this year’s event, so we settled for the next best thing—setting up in the susquehannawildlife.net headquarters garden. So here it is, yesterday’s eclipse…

Solar Eclipse 2024 — Here’s one of our first views through a break in the clouds as photographed using a number 12 welder’s glass to shield the camera.

Solar Radio Shutdown during Annular Solar Eclipse 2024 — Our home-brew solar-powered radio shut down.

Mourning Dove cooing during solar eclipse. — Our male Mourning Dove perched above its nests site and began a premature evening chorus of sorrowful coos.

Fish Crow Returning to Roost during solar eclipse — The flock of Fish Crows that has been lingering in the area for several weeks was seen making their way to a small grove of nearby evergreens where they often spend the night.

Turkey Vulture Flapping Its Way to Roost during solar eclipse. — Since early winter, Turkey Vultures have been roosting at a site about a half mile from our headquarters. Each evening, they can be seen leisurely riding the late afternoon thermals as they glide in to pass the night at their favored resting spot. During the height of the eclipse, as clouds co-conspired to quickly darken the sky and diminish the thermal updrafts, our local vultures were making a hurried scramble, flapping madly to get back to their roost.

The Eclipse of 2024 Wanes — Within fifteen minutes, the cloud cover thinned and the moon started to slide away. Rays of sunshine quickly renewed the pace of an early spring afternoon. Soon, the bees were buzzing around, the crows were out looking for trash, and the vultures were piloting the skies in search of deadbeats.

August 1, 2023August 2, 2023

Rocket’s Red Glare on the Susquehanna

At just after 8:30 this evening, an Antares rocket carrying a Cygnus supply capsule launched from the NASA flight facility on Delmarva Peninsula at Wallops Island, Virginia. We took a walk on the Veterans Memorial Bridge over the Susquehanna at Columbia-Wrightsville to have a look at the spacecraft as it powered its way into orbit for a rendezvous with the International Space Station.

Unfortunately, a smoky haze from wildfires still burning in Canada obscured our view of the ascending rocket as it cleared our horizon and made its way downrange across the Atlantic.

Antares rocket launch through smoke haze. — This faint glow from the Antares rocket was visible through thick haze in the southeast sky for less than ten seconds.

But on the brighter side, we were spared any significant disappointment. It just so happened that the Antares/Cygnus rocket wasn’t the only launch visible from the Veteran’s Memorial Bridge this evening…

Rocket Launch? — A rocket climbing skyward above Columbia, Pennsylvania.

Fireworks Above Columbia, Pennsylvania — A National Night Out fireworks display in Columbia preceded the Antares rocket launch.

Fireworks "Grande Finale" on the Susquehanna at Columbia, PA — This fireworks grand finale on the Susquehanna ended just minutes prior to the liftoff in Virginia.

Fishing the Eelgrass Beds — Smoke and rockets aside, it was an otherwise peaceful and picturesque evening to be on the river.

June 7, 2023June 8, 2023

Photo of the Day

The Sun in Wildfire Smoke — Nearly a full hour before it set below the western horizon, the sun faded into the clouds of Canadian wildfire smoke filling the skies of the lower Susquehanna valley and was gone. Look closely…the haze filtered the sun’s glare so completely that several sunspots are visible.

April 10, 2020April 16, 2020

Rocket Science

Fifty years ago, the world’s attention was fixed on the fate of the Apollo 13 astronauts—Commander Jim Lovell, Lunar Module Pilot Fred Haise, and Command Module Pilot Jack Swigert—after an explosion disabled their spacecraft and changed a mission to explore the moon into an improvised operation to return them safely to the earth. Perhaps this anniversary comes at a fortuitous time. The story of Apollo 13 may have parallels and lessons pertinent to present-day events and the concerns of people in America and around the world.

In April, 1970, Jack Swigert was a last-minute replacement for the original Apollo 13 Command Module Pilot Ken Mattingly after Mattingly was exposed to German measles (rubella) prior to the mission. Mattingly had been training with fellow backup crew members John Young and Charles Duke when Duke came down with the disease after he and his family had visited friends whose three-year-old son was suffering the effects of the infection. NASA was wary of contagions that could spread among the astronauts while isolated in a space capsule during a lengthy journey, possibly incapacitating the entire crew. Tests on the astronauts found that Mattingly, like Duke, had lacked antibodies to the rubella virus and could therefore become ill during the flight. Mattingly alone could get sick—Lovell and Haise, possessing resistance to rubella, could not. Nevertheless, the decision was made to substitute Swigert for Mattingly. Swigert proved competent for the late change partly because he had developed many of the emergency procedures for operating the Command Module. Mattingly, who never did get measles, along with Duke and Young, would be the crew for the Apollo 16 moon landing in April, 1972.

NASA preflight meeting discussing the replacement of Mattingly with Swigert just before the launch. Left to right: Chief of Flight Operations Donald “Deke” Slayton, Lovell, Mattingly, and Swigert. (NASA image)

Apollo 13 was launched as scheduled on April 11, 1970, at 2:13 P.M. E.S.T. and was on its way to a planned third landing on the lunar surface.

Launch of Apollo 13 using the Saturn V, the most powerful rocket ever flown. The Command Module would use the call sign “Odyssey”, the Lunar Module “Aquarius”. (NASA image)

After two successful landings, network television found no sensation in the story of yet another trip to the moon. There was little coverage of the mission’s first fifty-five hours. Then, fifty-five hours and just more than fifty-five minutes into the flight, and just two minutes after fulfilling Mission Control’s request to turn on fans to stir the oxygen tanks so that their contents could be measured, Jack Swigert radioed, “Okay, Houston, we’ve had a problem here.” Then Lovell repeated his message, “Houston, we’ve had a problem.” Within a minute, Fred Haise was listing some metering anomalies and alarm activations for Mission Control and added, “And we had a pretty large bang associated with the caution and warning there.” Apollo 13 was about 205,000 miles from earth—it was just after 10 P.M. E.S.T., April 13, 1970.

Thirteen minutes after the “bang”, Lovell radioed Mission Control while looking out the capsule’s window, “We are venting something out into the…into space.” Apollo 13 was losing it’s oxygen, and its electric supplies. They didn’t know it at the time, but oxygen tank number two had exploded and damaged either a valve or tubing on tank number one—the Command Module’s only other source of oxygen—and both were losing their contents into space. Two of the three fuel cells had failed as well. Without oxygen, the remaining fuel cell in the Service Module would fail to make electricity for operation of the Command Module. Worse yet, the astronauts would not be able to breathe. Without delay, engineers and scientists on the ground went into action to develop alternatives to the original flight plan.

The damage caused to the Service Module by the explosion of oxygen tank #2 wasn’t visible until it was jettisoned about five hours before Apollo 13 reached earth. (NASA image)

Power in the Command Module had to be conserved for reentry, so with just fifteen minutes of electricity remaining, Lovell and Haise moved into the “lifeboat”, the Lunar Module, and began powering it up while Swigert finished shutting down the systems aboard Odyssey to conserve its remaining energy for the end of the mission. Haise, who had spent fourteen months at Grumman’s manufacturing facility on Long Island, was intimately familiar with the Lunar Module’s operating systems. He powered-up essential systems and began calculating whether the consumables on Aquarius would last for the time it would take to go around the moon and “slingshot” back to earth.

To change the course of Apollo 13 from a moon orbit trajectory to one that would whip around the back of the moon and send them home, Lovell used the Lunar Module’s descent engine to perform a 35-second-long course correction burn. This burn commenced five hours after the explosion at 3:43 A.M. E.S.T. on the morning of April 14. Apollo 13 was then on a free-return trajectory to loop around the moon and return to earth.

Haise had in his possession notes from previous missions which he consulted to determine that they would run out of water about five hours before returning to earth. Fortunately, his notes also showed that the spacecraft’s mechanical systems could remain viable without water cooling for seven or eight hours. Astronauts reduced their water intake to six ounces a day, one fifth of normal, and attempted to compensate by drinking fruit juices and eating wet-packed hot dogs and similar foods. Their efforts to conserve water succeeded, but did lead to the crew becoming dehydrated.

For breathing, there was a sufficient supply of oxygen in the Lunar Module ascent stage where the astronauts would be taking refuge for the remaining four days of the journey. As a backup, there was oxygen in the two suits that were intended for the moonwalk and two more tanks in the ascent stage of Aquarius. Less than half of the oxygen supply was used during the return trip.

Procedures worked out by engineers and tested in a simulator on the ground allowed the crew to use only one fifth of the power normally required during the Lunar Module’s intended forty-five hours of useful life, thus enabling its batteries to last for a ninety-hour-long return trip and add charge to the Command Module batteries—with some energy to spare. To make it back to earth within the ninety-hour time window, the return trip would need to be shortened by nine hours.

The trajectory of Apollo 13’s loop behind the moon had carried them further away from earth than any other humans have ever gone. Two hours after swinging around the moon, Lovell prepared to perform a second burn with the Lunar Module’s descent engine—five minutes in duration—to increase Apollo 13’s return speed and shorten the time it would take to get back home. For navigational alignment during the burn maneuver, debris around the spacecraft made using the sextant to sight stars impossible. Scientists on the ground came up with coordinates allowing Lovell to use the sun as a navigation reference instead. The burn was a success.

Lithium hydroxide canisters remove the carbon dioxide gas, which is continuously produced by the respiration of the astronauts, from the atmosphere of a spacecraft. The Lunar Module’s canisters were designed to protect two astronauts for two days. Because it was being used as a “lifeboat”, Aquarius was hosting three astronauts for four days. After one and a half days of use by three men, an alarm warned that the carbon dioxide levels in the Lunar Module were getting dangerously high. Spare canisters from Odyssey could be used, but there was a problem—they were square, those used on Aquarius were round.

Engineers on the ground went to work using materials that would be available aboard the Apollo 13 spacecraft to improvise a solution. They came up with an adapter design using duct tape, a plastic bag, and cardboard to fabricate a “mailbox” that would attach square lithium hydroxide canisters to the round air handling tubes in the Lunar Module. After testing on the ground, the detailed verbal instructions for constructing the life-saving invention were radioed by Joe Kerwin from Mission Control to Aquarius. Haise and Swigert assembled and installed two of the life-saving devices. Carbon dioxide levels soon dropped back within acceptable parameters.

The makeshift adapters that were built to install square lithium hydroxide “scrubber” canisters on the round air supply tubes in Aquarius forever endeared duct tape to every Mr. Fixit on earth. (NASA image)

The astronauts endured a lack of sleep, heat, water, and food during the trip home. All were dehydrated and collectively they lost over thirty pounds of body weight. As they approached earth, the crew prepared to implement the new procedures for re-energizing the cold damp systems of the Command Module. Ground personnel had drafted and tested this set of startup instructions in just three days instead of the thirty days that such work usually requires. It was critical that the circuits that were energized did not collectively exceed the amperage available from the batteries on Odyssey.

Jack Swigert carefully brought Odyssey back to life using the new procedures, which were radioed, step by step, from Mission Control. Short circuits, feared due to the moisture that had condensed on all the cold surfaces in the Command Module, were not a problem. Improvements to the insulation on the wiring and electrical components throughout the interior of the space capsules following the Apollo 1 fire is believed to have safeguarded against any mishaps.

Four hours before reentry, at 8:15 A.M. E.S.T. on April 17, 1970, the Service Module was jettisoned and photographed as the crew got its first look at the damage caused by the explosion. Just an hour before reentry, Lovell and Haise joined Swigert in the Command Module. At 11:43, the Lunar Module was jettisoned and drifted away.

The Lunar Module Aquarius after release from the Command Module capsule Odyssey. Aquarius later reentered earth’s atmosphere and was mostly destroyed. The large pieces that survived descent splashed down at sea and sank. (NASA image)

Apollo 13 reentered earth’s atmosphere and experienced the usual communications blackout as the capsule sizzled through an envelope of ionized air. Mission Control and the world rejoiced as cameras televised images of deployed parachutes and a splashdown in the Pacific Ocean less than four miles from the recovery ship, the U.S.S. Iwo Jima, at 1:08 P.M. E.S.T. Possibly as many as one billion people were watching.

The crew of Apollo 13, (left to right) Haise, Lovell, and Swigert, on the deck of the U.S.S. Iwo Jima less than an hour after splashdown. (NASA image)

Flight Director Gene Kranz and Mission Control celebrate the safe return of Apollo 13. (NASA image)

The families of the astronauts had traveled aboard Air Force One along with President Richard Nixon to Honolulu, Hawaii, and were waiting for the Apollo 13 crew when they arrived there from American Samoa on April 18. Nixon presented the men with the Presidential Medal of Freedom.

“…The men of Apollo 13, by their poise and skill under the most intense kind of pressure, epitomize the character that accepts danger and surmounts it…Theirs is the spirit that built America.”

Among the greatest legacies of the earth orbit and moon missions were the scientific and technological achievements that allowed people to live and travel in space using a minimum of resources. Apollo 13 took these minimums to the extreme—using everything as effectively and efficiently as possible. It was one of the pinnacle achievements of the manned spaceflight program.

Fifty years later, are we embracing these and more recent innovations to live comfortably but wisely?

President John F. Kennedy, in his 1962 speech at Rice University, beckoned Americans to strive for a seemingly unreachable goal. A goal that would motivate a people to determine their own destiny and not have destiny determined for them.

“…We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone…”

Kennedy urged his country to take the risk and go to the moon. Despite the dangers, despite the hesitations of the medical community, and in spite of the naysayers, they accepted the challenge and succeeded.

Have Americans lost the will to shape their own destiny? Are they content with blind obedience, mediocrity, and shopping with a dirty rag over their face? Let your friendly editor give you a hint. The people who happen to be front and center in the news today, fifty years after Apollo 13, aren’t rocket scientists. In fact, they have a hard time swallowing anything science has to offer, unless, of course, it can be twisted to back up their sneaky little schemes. But they’re the leadership—elected dimwits and entrenched bureaucrats—and they rule by consent of the governed. So the matter is decided. Look at the bright side though, at least the creeps have a career to protect, so we’ll always be certain of their motivation.

SOURCES

Lovell, James A. 1975. “Houston, We’ve Had A Problem; A Crippled Bird Limps Safely Home”. Apollo Expeditions to the Moon. National Aeronautics and Space Administration. Washington, DC. pp. 247-263.

SOURCES THAT APPARENTLY NOBODY READS

Broseau, Lisa M., and Margaret Seitsema. 2020. “Commentary: Masks-for-all for COVID-19 Not Based on Sound Data”. University of Minnesota Center for Infectious Disease Policy https://www.cidrap.umn.edu/news-perspective/2020/04/commentary-masks-all-covid-19-not-based-sound-data Accessed April 10, 2020.

Davies, Anna, Katy-Anne Thompson, Karthika Giri, George Kafatos, Jimmy Walker, and Alan Bennett. 2013. “Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?”. Disaster Medicine and Public Health Preparedness. 7:4. pp. 413-418.

MacIntyre, C. Raina, Holly Seale, Tham Chi Dung, Nguyen Tran Hien, Phan Thi Nga, Abrar Ahmad Chughtai, Bayzidur Rahman, Dominic E. Dwyer, and Quanyi Wang. 2015. A Cluster Randomized Trial of Cloth Masks Compared with Medical Masks in Healthcare Workers. BMJ Open. 5:e006577. doi:10.1136/bmjopen-2014-006577.

March 22, 2020June 12, 2021

A Coronal Mass Ejection

As spring begins, our thoughts often turn, if only briefly, to the sun and the welcome effect its higher angle in the sky and the lengthening hours of daylight will have on our winter-weary lives. Soon, spring thunderstorms and warm humid air will make our crops thrive. Plant buds will open to reveal flowers and leaves, and wildlife will hurry to raise a new generation. We’re reminded that the sun is the source of earth’s life—and is its ongoing benefactor.

The rotation period of the sun’s outer layers, the convective zone and the visible photosphere, chromosphere, and corona, is approximately 25 earth days at the equator and as long as 36 days at the poles. Closer to the core, the rotation period in the radiative zone is about 27 days. Note the coronal streamers, filaments of plasma extending into space around the sun. (Image courtesy of Large Angle Spectrometric Coronagraph Experiment/Naval Research Laboratory Solar and Heliospheric Observatory Team)

Coincidentally, there was, during the first full day of spring, an explosion of plasma from the sun—a Coronal Mass Ejection. It happened to occur on the side of the sun currently facing away from earth, so the enormous cloud of magnetic energy won’t be affecting radio communications or electric transmission here.

Friday’s Coronal Mass Ejection can be seen in the following series of images. To protect the camera’s sensor, the direct light of the sun was blocked by an occulter at the center of each picture. The location of the sun’s disk is indicated by the white circle. In this set, the ejected plasma appears as a cloud emerging from behind the left side of the shield and racing millions of miles into space. The speed of a plasma cloud produced by a Coronal Mass Ejection varies. When directed at earth, some can reach our planet in less than a day—others may take several days to arrive.

(Solar and Heliospheric Observatory/Large Angle Spectrometric Coronagraph Experiment images)

Currently though, the term “Coronal Mass Ejection” may cause one to bristle and think of concerns other than the cosmos—Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the Wuhan flu chief among them.

A Coronal Mass Ejection? (Centers for Disease Control image)

Well, perhaps the promise of warming weather and humid days will help assuage our anxieties.

Colds and flu are certainly more prevalent in winter than during the other seasons of the year. Cases of these diseases begin creeping through schools and workplaces just in time for the year-end holidays. They persist into early spring each year. Then, as we spend more time outdoors in the sunshine and fresh air of April and May, their incidence wanes. Soon the sneezing and coughing is mostly pollen-related and less often the result of transmitted viruses.

In addition to our liberation from buildings crowded with people, spring heat introduces another factor that is apparently responsible for subduing the rapid transmission of viruses—humidity. February and March are typically the driest months of the year in the lower Susquehanna valley. The air outside is cold and dry. The air inside a heated building can be worse.

Researchers have found that viruses in aerosols produced by coughing, sneezing, breathing, and talking survive longer in drier air than in humid air. A NIOSH and CDC funded study (Noti, et al., 2013) mechanically “coughed” aerosols containing H1N1 virus into a simulated examination room. They discovered that “…one hour after coughing, ∼5 times more virus remains infectious at 7-23% RH (relative humidity) than at ≥43% RH.” This is a significant discovery and may shed light on why the end of heating season and the arrival of warmer humid springtime air coincides with the end of cold and flu season. The study’s analysis determined that “Total virus collected for 60 minutes retained 70.6-77.3% infectivity at relative humidity ≤23%, but only 14.6-22.2% at relative humidity ≥43%.” Specifically, they found that the greatest effect of higher relative humidity occurs during the first fifteen minutes after the cough, and that virus in droplets exceeding 4μM in diameter had the most significant reduction in that time—ninety percent.

It looks like a little global warming wouldn’t hurt right now.

So remember, respect the sun—fear asteroids.

SOURCES

Burnham, Robert, Alan Dyer, Robert A. Garfinkle, Martin George, Jeff Kanipe, and David H. Levy. 2006. The Nature Companions Practical Skywatching. Fog City Press. San Francisco, CA.

Noti, J.D., F. M. Blachere, C. M. McMillen, W. G. Lindsley, M. L. Kashon, D. R. Slaughter, et al. 2013. “High Humidity Leads to Loss of Infectious Influenza Virus from Simulated Coughs”. PLoS ONE. 8:2 e57485. https://doi.org/10.1371/journal.pone.0057485

July 20, 2019April 10, 2020

How I Spent My Summer Vacation

It’s a hot summer weekend with a sun so bright that creosote is dripping from utility poles onto the sidewalks. Dodging these sticky little puddles of tar can cause one to reminisce about sultry days-gone-by.

Sometime in July or August each year, about half a century ago, we would cram all the gear for seven days of living into the car and head for the beaches of Delmarva or New Jersey. It was family vacation time, that one week a year when the working class fantasizes that they don’t have it so bad during the other fifty-one weeks of the year.

The trip to the coast from the Susquehanna valley was a day-long journey. Back then, four-lane highways were few beyond the cities of the northeast corridor and traffic jams stretched for miles. Cars frequently overheated and steam rolled from beneath the hoods of those stopped to cool down. There were even 55-gallon drums of non-potable water positioned at known choke points along some of the state roads so that motorists could top off their radiators and proceed on. Within these back-ups there were many Volkswagen Beetles pausing along the side of the road with the rear hood propped up. Their air-cooled engines would overheat on a hot day if the car wasn’t kept moving. But, despite the setbacks, all were motivated to continue. In time, with perseverance, the smell of saltmarsh air was soon rolling in the windows. Our destination was near.

At the shore, priority one was to spend plenty of time at the beach. Sunbathers lathered up with various concoctions of oils and moisturizers, including my personal favorite, cocoa butter, then they broiled themselves in the raging rays of the fusion-reaction furnace located just eight light-minutes away. Reflected from the white sand and ocean surf, the flaming orb’s blinding light did a thorough job of cooking all the thousands of oil-basted sun worshippers packing the tidal zone for miles and miles. You could smell the hot cocoa butter in the summer air as they burned. Well, maybe not, but you could smell something there.

By now, you’re probably saying, “Hey, why weren’t you idiots wearing protection from the sun’s harmful U.V. rays?”

Good question. Uncle Tyler Dyer reminds me that back in the sixties, a sunscreen was a shade hung to cover a window. He continued, “Man, the only sun block we had was a beach ball that happened to pass between us and the sun.”

A beach ball doesn’t cast much of a shadow. (NASA Solar Dynamics Observatory base image)

During several of our summertime beach visits in the early 1970s, we got a different sort of oil treatment—tar balls. We never noticed the things until we got out of the water. Playing around at the tide line and taking a tumble in the surf from time to time, we must have picked them up when we rolled in the sand.

Uncle Ty wasn’t happy, “Man, they’re sticking all over our legs and feet, and look at your swim trunks, they’re ruined. And look in the sand, they’re everywhere.” The event was one of the seeds that would in time grow into Uncle Ty’s fundamental distrust of corporate culture.

Looking around, tar balls were all over everyone who happened to be near the water. Rumor on the beach was that they came from ships that passed by offshore earlier in the day. The probable source was the many oil spills that had occurred in the Mid-Atlantic region in those years. During the first six months of 1973 alone, there were over 800 oil spills there. Three hundred of those spills occurred in the waters surrounding New York City. The largest, almost half a million gallons, occurred in New York Harbor when a cargo ship collided with the tanker “Esso Brussels”. Forty percent of that spill burned in the fire that followed the mishap, the remainder entered the environment.

When it was time to clean up, we slowly removed the tar from our legs and feet by rubbing it away with a rag soaked in charcoal lighter fluid or gasoline. Needless to say, our skin turned redder than it had already been from sunburn.

Letting swimmers and wildlife roll around in the sand is no longer the preferred method of cleaning up tar balls from man-made oil spills. Here, President Obama examines tar balls resulting from the April 20, 2010, B.P. Deepwater Horizon spill in the Gulf of Mexico. An organized cleanup effort followed this May 28, 2010, visit to the polluted Port Fourchon beach in Louisiana.

After a full day in the surf, we’d be on our way back to our “home base” for summer vacation, a campground nestled somewhere in the pines on the mainland side of the tidal marshes behind our beach’s barrier island. There, we’d shake the sand out of our trunks and savor the feeling of dry clothing. As the sun set, the smoke, flicker, and crackle of dozens of campfires filled the spaces between the tents and camping trailers. Colored lights strung around awnings dazzled sun-weary eyes as night descended across the landscape. We’d commence the process of incinerating some marshmallows soon after. Then, sometime while we were roasting our weenies and warming our buns, we’d hear it.

His device didn’t have a very good muffler. It sounded like a rusty old lawn mower running on the back of a rusty old truck that didn’t sound much better. And you could see the cloud rising above the campsites around the corner as he approached. It was the mosquito man, come to rid the place of pesky nocturnal biting insects. Behind him, always, were young boys on bicycles riding in and out of the fog of insecticide that rolled from the back of the truck.

Curious children seen following the mosquito man in a 1947 Universal Newsreel.

One was wise to quickly eat your campfire food and put the rest away before the fog rolled in. You had just minutes to choke down that burned up hot dog. Then the sense of urgency was gone. Everyone just sat around at picnic tables and on lawn chairs bathing in the airborne cloud. A thin layer of insecticide rubbed into the skin along with the liberal doses of Noxzema being applied to soothe sunburn pain will get you through the night just fine.

By the early 1970s, fogging of campgrounds to eliminate nuisance mosquitos was conducted using primarily the insecticide carbaryl (Sevin). Prior to that, in the years following World War II, DDT was the one-trick pony for killing everything everywhere. In 1947, the youth of San Antonio, Texas were subjected to repetitive direct spraying with DDT to eliminate the “germs” responsible for poliomyelitis. It was a misguided use of the pesticide. (Universal Newsreel image)

Don’t you kids know that there’s sodium nitrite and saturated fat in those luncheon meats you’re eating? And the bread, aren’t you concerned about all that gluten? Oh, and by the way, they’re spraying you down with DDT again. It really happened in 1947 in San Antonio, Texas. (Universal Newsreel image)

Perhaps the most memorable event to occur during our summer vacations happened at the moment of this writing, fifty years ago.

We were vacationing in a campground in southern New Jersey. Our family and the family of my dad’s co-worker gathered in a mosquito-mesh tent surrounding a small black-and-white television. An extension cord was strung to a receptacle on a nearby post, and the cathode ray tube produced the familiar picture of glowing blue tones to illuminate the otherwise dark scene. There was constant experimentation with the whip antenna to try to get a visible signal. There were no local UHF broadcasters and the closest VHF television stations were in Philadelphia, so the picture constantly had “snow” diminishing its already poor clarity. But we could see it, and I’ll never forget it.

Neil Armstrong steps off the landing gear pad to be the first human to walk on the moon. July 20, 1969, 10:56 P.M. E.D.T. (NASA image)

Armstrong left the field of view of the LEM-mounted camera for minutes at a time as he completed various tasks. TV viewers heard audio of his conversations with partner Edwin “Buzz” Aldrin and Houston Mission Control during these interludes. It was definitely not coverage designed for the short attention span of typical TV audiences. (NASA image)

Edwin “Buzz” Aldrin descends the ladder on the LEM’s landing gear to reach the moon’s surface 19 minutes after Armstrong. (NASA image)

Because NASA used a different video format than broadcast television, images seen at the time of the moon walk were of poor quality, produced by aiming a TV camera at a NASA monitor. Quality still images, including this one of Edwin “Buzz” Aldrin descending to the lunar surface, were available only after the astronauts returned exposed film to earth for processing. (NASA image by Neil Armstrong)

Edwin “Buzz” Aldrin overlooking the LEM “Eagle” at Tranquility Base. (NASA image by Neil Armstrong)

Neil Armstrong took this iconic image of Edwin “Buzz” Aldrin using a Hasselblad camera. His reflection can be seen in Aldrin’s visor. (NASA image by Neil Armstrong)

Neil Armstrong (1930-2012), first man on the moon. (NASA image)

SOURCES

Andelman, David A. “Oil Spills Here Total 300 in ’73”. The New York Times. August 8, 1973. p.41.

Cortright, Edgar M. (Editor). 1975. Apollo Expeditions to the Moon. National Aeronautics and Space Administration. Washington, DC.

December 24, 2018June 8, 2024

Our Oasis

Fifty years ago, the crew of Apollo 8 became the first humans to leave Earth and journey to its closest celestial body, the Moon. Launching on the morning of December 21, 1968, they were the first to enter space from atop the powerful and complex Saturn V rocket. Their eyes would be the first to see the Earth as an entire sphere and to orbit the Moon and observe its obscure far side. For many back home, they changed not only the way we understand the Moon, but how we perceive the uniqueness and fragility of Earth.

On December 23, 1968, the crew of Apollo 8 transmitted this black-and-white television image of Earth to an awe-struck global audience back home. Astronauts Frank Borman, Jim Lovell, and Bill Anders were the first of only 24 persons to date who have observed, with their own eyes, the entire disk of the planet, seen here from 176,533 miles during their outbound journey to orbit the Moon. (NASA Image)

Striking color photographs were processed and distributed following the return of Apollo 8’s crew from their successful Christmas Eve orbits of the Moon. Exposed while outbound on December 22, 1968, this spectacular image includes the Americas, the Atlantic Ocean, and western Africa. Taken within a day of the Northern Hemisphere’s Winter Solstice, the photograph clearly shows the shadow of darkness draped across the Arctic region. (Science & Analysis Laboratory, Johnson Space Center, NASA Image)

Photographed by astronaut Bill Anders, the well-known “Earthrise” image reveals our blue world as seen from the Apollo 8 Command Module which at the time was emerging from the opposite side of the moon during one of its Christmas Eve lunar orbits. (NASA Image by Bill Anders)

Said Command Module Pilot Jim Lovell during a televised broadcast from lunar orbit on Christmas Eve half a century ago, “The vast loneliness up here of the Moon is awe-inspiring, and it makes you realize just what you have back there on Earth. The Earth from here is a grand oasis in the big vastness of space.”

August 21, 2017December 24, 2018

A Little Black Spot on the Sun Today

Was there a better place to have a look at the dark side of the moon easing across the summer sun than from the Pothole Rocks at Conewago Falls? O.K., alright, so there must have been a venue or two with bigger crowds, grand emotions, prepared foods, and near darkness, but the pseudolunar landscape of the falls seemed like an ideal observation point for the great North American solar eclipse of 2017.

The craters of the moon right here on earth, the Pothole Rocks of Conewago Falls.

Being the only person on the entire falls had its advantages, not the least of which was the luxury of pointing the camera directly at the sun and clicking off a few shots without getting funny looks and scolding comments. Priceless solitude.

Point that camera right at that eclipse for a nice little photograph of the big event.

If you think it looks like the above photograph was taken in a house of mirrors, then you’re pretty sharp. You’ve got it figured out. After getting a bad case of welder’s burns on the first day of a job at a metal fabricating shop during my teen years, I learned the value of a four dollar piece of glass.

A number 12 welder’s lens in action while viewing and photographing today’s solar eclipse.

The eclipse at 2:19 P.M. Eastern Daylight Time (18:19 U.T.C), nearly as good as it was going to get at Conewago Falls. The lunar disc would continue to the left, leaving the top fifth of the sun “uneclipsed”.

For those of you who prefer not to look at the sun, even with protection (I heard those S.P.F. 30 sunblock eye drops were a fraud…I hope you didn’t buy any.), here is the indirect viewing method as it happened today.

The eclipse is projected into the bottom of a cavernous hole in a Pothole Rock. (Three or four people can sit inside this hole.) The tube, lenses, and mirrors of one side of a pair of binoculars were used to focus the thin sliver of sunlight onto the diabase stone “floor”. The optics have inverted the image.

If you were to our south in the path of totality for this eclipse, you probably noted reactions by flora and fauna. Here, there was really not much to report. The leaves of Partridge Pea didn’t fold for the night, birds didn’t fly away to roost, and the chorus of evening and nighttime singing insects didn’t get cranked up. The only sensation was the reduced brightness of the sun, as if a really dark cloud was filtering the light without changing its color or eliminating shadows. And that was the great solar eclipse of 2017.