City Creek Nature Notes – Salt Lake City

July 11, 2017

July 6th

Dry Fork Canyon

3:45 p.m. It is the third day of 100 degree Fahrenheit heat as I return to the Bonneville Shoreline Trail behind the University of Utah Hospital. I plan to jog up Dry Fork Canyon at the southeast end of the Salt Lake salient and then west along the Shoreline Trail above the Avenues. The Trails goes up Dry Fork for about one mile, crosses a pass, and then traverses a series of gullies that come down from the ridgeline to the Avenues and city below. The Trail begins in a invasive Cheat grass sea that is typical of the city’s foothills. Here, small light brown House crickets (Acheta domestica), another non-native, infest the Cheat grass. There are twenty or thirty per square yard. I round a corner into Dry Fork Canyon, and quickly its narrow walls close in and shade the canyon. The Fork’s walls are covered in dense Gambel’s oak forest, and this forest broken higher up by fields of the brown sun-dried husks of Arrowleaf balsamroot (Balsamorhiza sagittata). In an example of color adaptation, at the base of the oaks, larger, unidentified grasshoppers live, but unlike the sun-exposed crickets, these are colored green in order to better blend in with their surroundings.

At a seep one-third of a mile up canyon, there is a mini-oasis. In ten feet with Wood’s rose bushes on either side, Common sulphur butterflies, Western tiger swallowtail butterflies, small bluet dragonflies, Common whitetail dragonflies, Western Yellowjacket wasps, and Circumpolar bluets, all compete for space and landing rights around a small ditch of shallow water.

Further up canyon, the oak forest comes alive with sounds of birds: Black-headed grosbeaks, Lazuli buntings and Song sparrows call from the oaks spaced perhaps 100 feet apart on both canyon walls. Their songs are clear and strong, and I estimate there are about 250 birds between the canyon mouth and the upper pass. Unexpectedly, this density exceeds that of the stream areas in City Creek Canyon. The birds here, unlike in the City Creek Canyon, are fearless. I am able to stand only five feet from a Lazuli bunting as it tilts its head back to make a song. I am able to make a good recording and spectral graph. I flush two California quails (Callipepla californica) from the brush.

House crickets may explain the high density of birds in Dry Fork Canyon, where as the name implies, there is no water. Assuming a cricket weighs about one-quarter gram (0.000551 lbs), then there are about 85 tons of cricket mass on the city facing foothills between Dry Fork Canyon and the peak at the top of North Terrace Hills Drive in Valley View Canyon (see June 10th) (3,097,600 square yards per square mile x 4 miles x 1.25 miles x 20 cricket per square yard x 0.000551 lbs. per cricket divided by 2,000 lbs. per ton). The crickets exist at a similar density for another ten square miles between Memory Grove in lower City Creek Canyon and milepost 3.5 above Bonneville Drive. This suggests that there may be about 300 tons of these non-native crickets, and this is more than enough to support the summer bird populations seen in Dry Fork and City Creek Canyon.

As the canyon dries out, purple Bull thistles (Cirsium vulgare) covered with small black ants, a blue-white thin-petaled Eaton’s aster (Aster eatonii a.k.a. Symphyotrichum eatonii), and invasive blue Chicory (Cichorium intybus L.) grow. The roots of Chicory are roasted and ground to make chicory coffee. The white-topped weed Hoary cress (Cardaria draba) is also found.

As I near the upper Trail pass out of Dry Fork, I count two Broad-tailed hummingbirds, and just before the pass, I am treated to a rare display by a pair of Black-chinned hummingbirds (Archilochus alexandri). The male has trapped a female hummingbird at the base of Gambel’s oak sapling. For several minutes the male does its pendulum mating dance. It rapidly flies back and forth in a figure-eight pattern about six feet across, its wings buzzing loudly. Then the male gives up, and he does two high speed runs over the female while making a zinging noise. At the pass out of Dry Fork, I am greeted by expansive views of the city and of the Great Salt Lake, fifteen miles in the distance. The Sun is pounding, but my spirit soars from both the views and the hummingbird’s display.

* * * *

Per Thoreau’s “Journal” on July 6th, 1851, he walks by moonlight and again sees it reflected in water. He notes crickets sing with a different frequency at night. On July 6th, 1852, he hears a pewee and a red-eye. He sees tufted vetch, a fern, a tansey, and a parsnip. He watches a pickerel in a stream. He hears a duck on a pond. On July 6th, 1856, he stumbles on a peet-weet with its nest and young. On July 6th, 1858, he hears and sees loons. On July 6th, 1859, he describes heart-leaf.

* * * *

On July 6th, 1905, the City passed Councilperson’s Woods proposed ordinance banned automobiles from City Creek Canyon. On the same day, the Salt Lake Tribune urged that the road should be sprinkled with oil to keep dust down. Also on July 6th, 1905, the City Council held a heated debate on whether a bridge should be constructed over City Creek Road in support of the Commercial Club’s proposed scenic boulevard (Salt Lake Tribune).

July 10, 2017

July 1st

Talking Plants – Part I – Hidden scents

2:00 p.m. In the heat of the afternoon, it is another butterfly day. Cabbage white and Western tiger swallowtail butterflies line the road. Families stroll through the heat on a holiday weekend.

It is also the time of mature trees. The giant trees of the canyon – those taller than seventy-feet – now dominate the canyon experience. Species include Box Elder trees, Rocky Mountain narrowleaf cottonwood trees and Freemont’s cottonwood trees (Populus fremontii). They now provide a partial canyon that protects the mid- to small-sized trees and the understory bushes from the harsh summer sun. Walking past one of these biological skyscrapers, one can feel the increase in humidity from their exhalations. In winter, their skeletons are ignored and when walking up-canyon during the cold season, one does not give them a passing thought.

At Guardhouse Gate, Black-headed grosbeaks and Lazuli buntings dominate. At picnic site 3, Song sparrows are prominent, and at third active zone of birds appears at milepost 1.1.

At seep below picnic site 6, the Starry solomon’s seal has, in seemingly a few days, been overrun by Western poison ivy (Toxicodendron rydbergii). It is now a deep green, and in the fall will turn a deep red (Sept. 23rd).

* * * *

Per Thoreau’s “Journal” on July 1st, 1852, he notes that rabbit’s foot clover is turning colorful, mulleins are turning yellow, wild roses are at their peak. He describes a white lily in depth. He hears a red-eye, oven-bird and a yellow-throat. On July 1st, 1854, he again notes that the edges of distant objects are distinct in clear air. He watches the shadows of clouds moving across the land. On July 1st, 1859, he notes white ranunculus is in bloom.

* * * *

Plants communicate with each other and with insects by volatile airborne chemical signals in order to coordinate defenses against herbivores (Hartley 2010, Hartley 2009, Alba 2012, Engelberth 2012, Heil and Karbon 2009, see Witzany and Baluska (ed) 2012). Experiments suggest that Box Elder trees, the Gambel’s oaks, the bushes of the understory, the Curly dock weeds, the Starry Solomon plants, the sagebrush, and the other plants currently active in the canyon are carrying on a conversation, unheard by human interlopers. Experiments have been done on plants outside species of the Gambel’s oak forest, but one example exists for communication between the sagebrush groves along east Bonneville Drive. In 2011, Shiojiri at Kyoto University, Karban at University of California at Davis and Ishizaki at Hokkaido University replicated and expanded Karban’s 2006 study on Great basin sagebrush (Artemisia tridentata) plant communication (Shiojiri, Karban and Ishizaki 2011). They found that the neighbors of sagebrush plants mechanically damaged with scissors but allowed to spread VOCs suffered less damage from grasshoppers than sagebrush plants not allowed to receive VOC emissions from the damage sagebrush. In short, sagebrush plants talk with their sagebrush neighbors and warn them to start producing insecticides to ward off grasshoppers. In 2008, Mäntylä et al at the University of Bristol demonstrated that birch trees issue volatile airborne chemicals, not detectable by humans, when attacked by caterpillars. To control scents, they contained some damaged branches in plastic bags, but left other branches exposed. Birds preferentially visited and attacked branches where trees’ VOC scent was present. In short, their Great Britain birches talk to birds. Although the specific species in investigated in Great Britain are not present in the canyon, the canyon hosts Birchleaf mountain mahogany (Cercocarpus montanus Raf.). In 2011, Mäntylä et al demonstrated a similar effect in Scottish pines (Mäntylä et al 2011). Engelberth notes that some plants use VOCs to signal predatory insects, e.g. predatory wasps, that they have been damaged by insect herbivores that are preferred foods of the predator insect (Engelberth 2012).

Plant species talking between themselves, with other species of plants, and with insects and birds may have arisen by conferring an evolutionary advantage (Heil and Karban 2010). By alerting its same-specie and inter-specie neighbors, sagebrush, for example, can create a herd-like resistance to grasshopper attacks. Similarly, by talking with insects and birds, plants create co-evolutionary relationships that benefit both the plant and associated insect eating birds (id., Engelberth 2012). Through 2010, Heil and Karban summarize known examples of plant “talking” with VOCs (id). In this Great Basin canyon, such communication has only been shown specifically for Great basin sagebrush, but Heil and Karban also list known plant VOC demonstrations for families of plants whose cousins are also present in the City Creek Canyon, including willow trees, sugar maples, poplar trees and alder trees. That the other trees and other plants present in City Creek Canyon are talking to a each other seems a reasonable extrapolation, but demonstration of their VOC communication remains to be shown by future researchers.

* * * *

On July 1st, 2001, City Planning Director Stephen Goldsmith notes that a gate has been added at Memory Grove to control traffic (Salt Lake Tribune). On July 1st, 1997, a small grass fire broke out near Memory Grove (Salt Lake Tribune). On July 1st, 1925, a Salt Lake Telegram editorial approved of the City’s use of “hoboes, drunkards and indolent men” on the prison road work crew then working in City Creek Canyon. On July 1st, 1920, twenty-five service men convalescing at St. Marks Hospital will be given a picnic outing in City Creek Canyon (Salt Lake Herald). On July 1st, 1919, a Salt Lake Telegram editorial reported that a large fire had been burning in City Creek for several days (Salt Lake Telegram). The Telegram reported rumors that the fire may have been started by I.W.W. members (id). (Famed I.W.W. organizer Joe Hill had been previously executed in Salt Lake City in November 1915.)

June 23, 2017

June 20th

Summer

First Day of Summer

External Link to Image

Comparison of City Creek Canyon Road near Mile 1.1 in Winter on November 24th and on the First Day of Summer, June 20th.

6:00 p.m. It is nearly 100 degrees Fahrenheit on this first day of summer. Although this is the longest day of the year, and the amount of total light is four times the amount of light that occurs on the winter solstice (March 21st), this is usually not the hottest day of the year. The Earth continues to absorb the sun’s heat by melting at the poles, and thus, the hottest days of the year with 100 plus degrees Fahrenheit are lagged by three or four weeks to the end of July. But the recent heat wave is an unusual preview of the coming summer hottest days. Today, and more typical of late July, the heat boils the water from the land, and in the afternoon, great cumulus clouds rise and re-deposit the day’s water during the cool of the evening. As I approach the canyon, the sky to the west is gray and boiling. The bottom of the cloud layer swirls in confused eddies and circles. Winds rage and the trees wave back and forth as if they are in a current below the surface of the ocean. Only the large Common whitetail dragonflies (Libellula lydia) hover in the strong breeze. The whitetail’s are misnamed; their tails are more often black. From the safety of the leaf screened branches, Song sparrows, Chirping sparrows and Black-headed grosbeaks call. First, the air smells of summer, but then it mixes with the rain primed, fresh moisture. Small spatters fall, and then a brief deluge comes. Runners on the road, including myself, jog without their shirts on. The afternoon storm passes, the air clears, and all is renewed.

Along the first mile road, Milkweed plants have grown large, fecund seed heads.

* * * *

Although Thoreau declares summer to begin informally on June 1st (see his “Journal” on June 1st, 1853), astronomically summer begins on June 20th. Per Thoreau’s “Journal” on June 20th, 1840, he sees mica particles glittering in sand. On June 20th, 1852, he notes blue-eyed grass flowers are closed in the before sunset, and he hears an American Bittern drumming on wood. He notes that grass fields are red tinged because the grass has gone to seed. On June 20th, 1853, he sees meadow-sweet flower and water lilies. During a full Moon walk, he admires how water reflects black under moonlight. He encounters a skunk. He notes that elm leaves and trunks have the same hue under moonlight.

* * * *

On June 20th, 2011, the Salt Lake Tribune published a historical article on George Ottinger, founder of Salt Lake’s fire department and later in the early 1900s, Salt Lake City’s Superintendent of Waterworks. He lived in an adobe house on 3rd Avenue and E Street. As a young man, Ottinger was an adventurer. He traveled as a sailor to China, Hawaii, the Indonesian Islands, and Panama, before returning for a late California Gold Rush (id). Omitted from this article is Ottinger’s witnessing of the last 1887 lynching of a man in downtown Salt Lake City. On June 20th, 1999, Utah Jazz assistant coach Mark McKown was injured while speeding down City Creek Canyon a bicycle (Salt Lake Tribune). He was accompanied by Utah Jazz star basketball player Karl Malone. On June 20th, 1998, City Creek Canyon was closed for three days after torrential rains caused a mudslide (Salt Lake Tribune). On June 20th, 1908, City Engineer L.C. Kesley budgeted 9,000 USD to extend an iron pipeline from State Street to City Creek Canyon Road and 50,000 USD for a distributing reservoir in City Creek (Salt Lake Herald). On June 20th, 1896, ore samples taken from the Willard Weihe claim in the Washington mine group, 1.5 miles north of Eagle Gate in City Creek Canyon, assayed at 94 and 84 USD per ton (Salt Lake Herald).

June 14, 2017

June 10th

Sego Lilies and Cheat Grass

6:30 p.m. The jet stream has reconnected over the Intermountain west to its usual spring route, and this has brought back strong, cooling breezes. This evening, I drive to the end of the road at North Terrace Hills Drive to walk up the trail from the Avenues to the south ridgeline of the Salt Lake salient that looks down into City Creek Canyon. I am looking for the Sego lily which blooms this time of year. One-quarter mile below where the trail intersects the road, I find patches of this Utah state flower (November 30th) among the parched Cheat grass. It is a bulb flower that rises from the hard ground sometimes without any leaves, and its four inch blossoms have delicate cream petals that are yellow at the base surrounded by splashes of dark red-purple. Against this central yellow backdrop, contrasting thick, white-colored stamens rise. I estimate about 80 lilies along are within a 100 feet along the trail for one-half mile below the ridgeline. Like most native desert wildflowers, it is a metaphor for beauty under adversity.

Also along the road are blossoming Canadian thistles (Cirsium arvense). Although a weed, its three inch light purple blossoms are a visually pleasing example of complexity in nature. Hundreds of small, spike like petals surround a central circular whirl of about 150 short, cylindrical, vertical stamens. The whirl pattern in its stamens betrays two counter-spirals of stamens that are arranged in left and right spiraling Fibonacci series.

Near the Sego lilies, there is a 10-inch diameter coyote burrow in the road bank to the west of the trail. That it sits along a heavily traveled mountain biking trail – perhaps between 50 to 100 people traverse this route each day – is unusual. It is not clear whether the burrow is currently occupied. The mouth of the burrow shows no recent signs of entry or exit, but there is contrasting excavated soil radiating below the entrance.

Below the ridgeline back over a mile to the trailhead, Gambel’s oak forest covers most of the land to the west of the trail, but the oaks only cover patches of ground to the east. Birds sing from their hiding places. I see Black-billed magpies at the trailhead and a Green-tailed towhee within the first quarter-mile. Near the ridge, Song sparrows, Black-headed grosbeaks, a hummingbird, and chukars are heard. From their calls within one-third of a mile of the ridgeline, I estimate 150 birds are present. None appear to be flying.

I reach the east-west running ridgeline and begin to climb another 150 feet to a small peak to the east of the intersection of trail and ridge. As with my last visit to this peak (January 5th), wind is blowing strongly from the north. The reason for the song bird’s grounding becomes apparent: in the steady wind, an avian farmer, a Cooper’s Hawk, hovers motionless about 20 feet above the ridge. The low Sun is filtered through clouds to the north, and its light sets the yellow molted breast feathers blazing. The hawk continues for hover for another minute, turns and glides off to the east just below the ridgeline.

From the peak, which bears a concrete and metal Salt Lake City survey corner marker indicating an altitude of 4,905 feet, or about 900 feet above the valley floor, there is a clear view down 20 miles of Wasatch Front Mountain Range from Grandview Peak and Little Black Mountain on the north, to Lone Peak on the south. In the evening light, the two sandstone geologic “U”‘s synclines that define Red Butte Canyon, Emigration Canyon, and part of Parleys Canyon are easily seen (January 9th). These sit on top of a larger deeper “U” shaped syncline of limestone that stretches from City Creek Canyon on the north and emerges again in Millcreek Canyon on the south. Perhaps this geology also explains why the streams in Red Butte and Emigration canyons reduce to trickle. Unlike City Creek and Millcreek with their limestone upper canyons, the surface bedrock of Red Butte and Emigration are porous sandstone. (Parleys Canyon contains two dams that hold back the stream.) Underground water may not be trapped along limestone layers. This is speculation, and another possibility is that Red Butte and Emigration canyons, unlike City Creek, were never reforested after the foresting and mining eras of the last half of the 19th century. Summer surface water may simply evaporate. To the west, the jet stream is marked by a fast moving line of clouds that extends from the southwest to the northeast.

Looking at the lands around the peak, they are one-third green oak forest, one-third dried brown Cheat grass, and one-third still green native brome. It must have been an impressive spring sight of green meadows before the invasive grasses arrived. The peak itself is covered in Cheat grass about six inches deep, and because of this year’s heavy winter snow, an acquaintance reports stands several feet in height along the Bonneville Shoreline Trail below this peak. The cheat grass is read to burn, and within the last week across the state, six large cheat grass wild fires of over 1,000 acres have burned. Several smaller cheat grass fires of a few acres in size also occurred in Salt Lake Valley over the last week, but those were quickly suppressed. Although overgrazing immediately after the Euro-american colonization of the valley in 1847 quickly converted fire resistant native bromes and bunch grasses to non-native adventive grasses spotted with sagebrush (March 13th), cheat grass was not present in the valley or on the Avenues ridgeline. This weed grass was introduced in California in 1870 (id), and the grass followed along the railroads lines east (Monson and Kitchen, 1992, p. 24), but may have also traveled as a contaminant in feed grain (id at 33). Cheat grass was first collected in Utah in 1894 by M. E. Jones on Provo, Utah (Barbour and Billings, p. 264; Monson and Kitchen). How fast it overtook native grasses statewide is unclear, but in 1932, Pickford of the Intermountain Forest and Range Experiment Station noted that while Cheat grass, which he called Downy brome, was found in all areas of the north half of the state, it was only dominate in the Great Salt Lake area (Pickford, 1932; Monson and Kitchen, 24). Pickford found that Cheat grass was most dense (11 percent coverage) on plots that had been both grazed and then subjected to a grass fire, but it was absent from plots that had never been grazed or subjected to a burn. What makes Cheat grass different is the higher frequency of its burn cycle and the higher temperatures at which it burns (Monson and Kitchen, 24). There is a direct relationship between the level of the prior winter’s precipitation and cheat grass fires in the following summer (Monson and Kitchen, 24). One-hundred and twenty-three years later, this hot burning grass covers the Avenues ridgeline, more than half of the City Creek canyon walls of the Salt Lake salient, and much of the State. The state and federal agencies spend about 83 million USD per year fighting wildfires in Utah (Stambro et al, 2014, Chap. 9), and much of that total is related to cheat grass fires.

The peak is also covered in unidentified, one-half inch nymph crickets. When walking forward, every step raises five or six nymphs that jump forward to avoid being crushed. They are marvels of camouflage, and their dark brown, light brown, dusky yellow and dirty white colors perfectly match the surrounding dried grass. They move at the slightest provocation and it takes several attempts to locate one for a photograph. Even knowing where it is, I have to stare at the brown grass for fifteen seconds before I can make out the cricket’s outline.

Despite the invasives, the expansive view of the surrounding hills and mountains is inspiring, and I return home a happy and contented person.

* * * *

In Thoreau’s “Journal” on June 10th, 1853, he notes honey locust, black willows and blackberries are in bloom. He hears a robin. On June 10th, 1856, he watches a huckleberry bird and finds a pigeon woodpecker nest with young. On June 10, 1857, he sees a snake. On June 10, 1860, he examines a bat suspended in the daytime forest.

* * * *

The Fibonacci series seen in the whirls of the center of a bull thistle plant reappears in many plant contexts, including how seeds are distributed around a pine cone (Klar, 2002) and how branches are radially distributed around on tree (Nelson 2004). The study of the arrangement of leaves on a plant is called phyllotaxis. There are several competing hypotheses for how leaves self-assemble themselves themselves in a Fibonacci series, and the prevailing theory is that these spatial patterns are the result of most-efficient packing solutions (Klar). Hormonal diffusion is also theorized but the actual mechanisms are unknown (id). Limited progress has been made in defining the theoretical mathematics of how a circle of undiffentiated meristem plant stem-cell tissue can transform into a spiral pattern and on identifying candidate biochemicals that control the process (Flemming, 2002).

Restoring areas contaminated with cheat grass has proven difficult and expensive in terms of both capital and labor (Barbour and Billings, p. 264; Monson and Kitchen). Salt Lake City and Salt Lake County have spent over 150,000 USD since 2008 trying to rehabilitate about 180 acres (0.3 square miles) in City Creek and Parleys Canyons that are contaminated with both Yellow starthistle and Cheat grass (see May 21st). The best strategy for restoration is reseeding following a cheat grass fire, but its effectiveness is limited to level areas (Barbour and Billings, 264-265) and not the steep slopes of City Creek Canyon and the Salt Lake salient. Although the city considered a controlled burn program in City Creek in 2010 (Gray and Harrison, 1999; Salt Lake Dept. of Public Utilities 2010, Salt Lake City Corporation 2010a), it was not pursued, and currently the Utah Conservation Corps is using the labor intensive method of manually denuding and spraying fields in lower Pleasant Valley, including along a steep slope (May 17th and May 21st).

* * * *

On June 10th, 2006, students at the Design Workshop recommend daylighting City Creek Canyon stream from the mouth of City Creek, along North Temple, all the way to the Jordan River (Salt Lake Tribune). Daylighting means raising the creek which now traverses the city’s center in underground pipes back to the surface. (Prior U.S. Corps of Engineer and City proposals recommended daylighting City Creek beginning at 700 West.) On June 10th, 1898, the National Guard plan exercises in City Creek Canyon (Deseret Evening News).

June 9th

First Tarantula and a Fake Bee

7:45 p.m. The jet stream to the northwest has begun to lower temperatures in the eighties and brings cooling evening breezes to the canyon. On this Friday evening, families seeking release from the days of heat fill the first few picnic sites. The heat wave is starting to end, and invasive Yellow sweet clover lines both sides of the road and waves under the wind. But there is no sign of summer’s yellow sunflowers along the road in Pleasant Valley. More soft tufts of pollen float down from the Rocky Mountain cottonwoods and their white down lines the roadside. Evening Black-headed grosbeak calls predominate in the first mile. A 3 inch unidentified dark blue-black dragonfly sails by. A unidentified light brown beetle, that has the shape of a solider beetle, has been seen on the road over the last few weeks. At the rear tip of its shell, there is a diamond shaped darker brown patch. On the road today, the nymph form of this beetle crosses the road. It is bright lime green. A black ant drags a bug twenty times its size to the side of the road.

Planted squarely across the center of a Wood rose blossom near mile 0.3, a member of the Galphyridae family of Bumble bee scarabs. The Bumblee bee scarab is a beetle, not a bee. Its wing shell has four horizontal white strips on the sides and two vertical white stripes on either side of the centerline. Its bee-like features are the abdomen that extends past the wing shell and is covered in fine yellow-white hairs. Its thorax is also covered with these fine hairs. Male Bumblee bee scarabs are sometimes found in flowers, as this oddly behaving one is. This scarab appears almost intoxicated. It is oblivious to my presence and seems to relish feeding on the rose’s pollen. Given its lethargic ways, the scarab’s mimicry of a bee might provide protection from predators, but given that birds eat bees, what predator does the scarab’s mimicry deter?

Near mile 0.4, the season’s first desert tarantula crosses the road. It is only two or three inches across. By mid-summer, it will grow to 5 to 6 inches across (August 17th).

* * * *

In Thoreau’s “Journal” on June 9th, 1850, he notes pitch-pine pollen collected on water. On June 9th, 1851, he observes that signs of the season are grass waving in the wind, new leaves on trees, and increasing louder crickets. On June 9th, 1853, he sees the season’s first lily bud and notes white clover is common. He sees starflowers in a meadow and gathers strawberries. He observes a hawk pair. On June 9th, 1854, he sees a lark and notes that the air has a high density of mayflies. On June 9th, 1857, he sees an indigo bird. On June 9th, 1860, he sees water bugs in a stream.

* * * *

On June 9th, 1915, a new reservoir on Fifth South that holds 10,000,000 gallons was inspected, and it will supplemented by a 5,000,000 gallon reservoir at Pleasant Valley (Salt Lake Herald). On June 9th, 1909, the Intermountain Republican reported that a flooding City Creek stream was still carving “numerous erratic channels down North Temple street”. Sandbags and manure was used by crews working under Street Supervisor J. T. Raleigh to create embankments, but this results in large pools of fetid water forming (id). The Tenth South canal overflowed its banks. On June 28th, 1905, the Commercial Club officially turned over the new Wasatch Boulevard to the City (Salt Lake Herald). The boulevard runs up City Creek Canyon, along 11th Avenue to Popperton Place, and then on to Fort Douglas. The boulevard then descends to Liberty Park (id). The Club plans to line the boulevard with trees and stone walls, interspersed with developed parks every few miles (id). On June 3, 1903, as a result of infrastructure improvements, the City had increased its water supply capacity to 28,000,000 gallons per day (Salt Lake Telegram). One hundred and thirty-one miles of water main pipe has been laid in the city, including City Creek Canyon (id). A city ordinance regulates residents sprinkling their lawns. The High line system in City Creek brings water to Popperton Place. On June 9th, 1877, the Salt Lake Tribune recommended City Creek Canyon Road for scenic carriage rides.

June 8th

First Loud Cricket with Metamorphosis

7:00 p.m. True night does not come until after 9 in the evening, and the start of the estival season is one week away. It the sixth day of late spring heat in the nineties, the jet stream is forcing its way into the Intermountain west, and the jet stream traveling southwest to the northwest over adjacent Nevada. This has brought high winds to the canyon. The leaved trees whip back and forth under its hand. In response to the days of heat, invasive Cheat grass (Bromus tectorum) that covers the hillsides on both sides of the Salt Lake salient have dried to an early season brown. The hills are a patchwork of brown Cheat grass and other later maturing bromes that are still green. Cheat grass is susceptible to burn in quick moving, high temperature fires, and authorities are worried over a bad fire season. Utah normally has 400 grass fires per year. Under the force of the wind, small birds restrict themselves to short thirty foot flights between trees. At the pond at picnic site 5, I startle a grounded Song sparrow, while a Black-headed grosbeak performs its trill call overhead.

As the wind starts to die down, I hear the first loud cricket – just one – of the season. I suspect that these also may be the cicadas heard yesterday in the tops of Gambel’s oaks (June 7th), and their wings have hardened overnight. In two months, large choruses of crickets will fill the canyon night air (August 15th and August 18th). Large mosquitoes (sp. Culiseta), possibly Marsh mosquitoes (Culiseta inornata), fly through the shadowed evening light.

* * * *

In Thoreau’s “Journal” on June 8th, 1851, he notes white pines have stamen blossoms. On June 8th 1853, a pair of hawks swoop on him as he walks near his nest. He notes that white pine is in flower. On June 8th, 1860, he notes that the summer afternoon shower season has begun. Red oak leaves have fully developed.

* * * *

Whether cricket or cicada, this clicking insect is a newly hatched pupae that has likely undergone some form of metamorphosis. In complete metamorphosis (holometabolous), such as that which occurs in butterflies, the egg hatches a larvae caterpillar, the caterpillar weaves a pupal sack, and then an adult emerges. In incomplete metamorphosis(hemimetabolism), an insect egg develops into an miniature adult, the nymph, and as it expands, it sheds its exoskeleton as it grows. In the canyon, incomplete metamorphosis is seen in crickets and Box elder bugs. Among the vertebrates, frogs and salamanders also undergo metamorphosis. Since insects, numerically, are the most diverse type of animals, 45 to 60 percent of all animals on the Earth undergo metamorphosis, and our mammalian form of infant development is a relatively infrequent mode (Jabr 2012). The evolutionary just-so story by which metamorphosis arose is that an intermediary stage of development allows the larval and nymph stages to exploit different food niches from adults in the same habitat. Truman and Riddiford suggest that natural selection acted on the hormonal mechanisms of ancestral species to create the radically different developmental stages (Truman and Riddiford 1999).

* * * *

On June 8th, 2003, the Salt Lake Tribune reported the experiences of many Salt Lake Valley residents in how they use the local canyons, including City Creek Canyon. The Outdoor Industry Foundation is conducting a study of dispersed recreation use in Utah, and it finds that 81 percent of Utahans engage in outdoor activities (id). On June 8th, 1951, The Audubon Society scheduled a trip up City Creek Canyon (Salt Lake Telegram). On June 8th, 1950, City tests of City Creek Canyon water show a high degree of purity and low coliform count (Salt Lake Telegram). On June 8th, 1933, the Wasatch Mountain Club scheduled a hike from Rotary Park in City Creek to Mueller Park (Salt Lake Telegram). On June 8, 1906, a committee of the City Council recommended that a permit to allow Henry B. Anderson to harvest 24 cords of cedar wood in City Creek be denied on the grounds of a need to protect the watershed (Salt Lake Telegram). On June 8, 1895, the Utah Forestry Association reported on its activities in reforesting stands of trees in City Creek Canyon (Salt Lake Herald). The Association also resolved to compile data on the extent of deforestation, rainfall and its impact on flooding (id).

June 7th

Clicking Katydids

4:30 p.m. This is the fifth day of ninety degree temperatures, and I go for a short jog up to milepost 0.5 and back down the Pipeline Trail. Looking at the jet stream charts at the California Regional Weather Service and National Weather Service maps for the last few days, the jet stream has broken and disconnected over much of the western and central continental United States. A large high pressure zone has disrupted spring’s conveyor belt of cooling ocean air.

Going up canyon near mile 0.4, I check one of the blue paint mosquito tree holes, and inside is a one inch beetle that is colored with Frank Lloyd Wright’s bright Cherokee red. (Later, after checking my insect guides, I am unable to identify it.) Just past the turn-off from the road to the trail, I begin to hear an odd clicking sound coming from the trees, and I stop the Gambel’s oak grove mid-way between road and Pipeline Trail. The sound is all around, but I cannot see its cause. There are also some small birds in the trees that confuse the source, but after a few minutes, I notice two or three insects on the branches that look like a large cricket but they have clear wings. These may be annual Mountain or Canadian cicadas (Okanagana canadensis). They are most probably Mormon crickets, which are katydids and not crickets. Katydids come into two forms: annual hatching and the more famous periodic hatching that rise from the ground once every 17 years. I cannot get close enough to identify these tree dwellers with certainty. I suspect that since they are newly hatched, their wings are still too soft to make the loud clicking sounds.

Along the Pipeline Trail, the blossom heads of Arrowleaf balsamroot plants that recently dominated the hillsides (April 29th) are all dried husks and full of seeds. The hot Sun has done more of its work. Along the road, the Western salisfy first seen a week ago (June 2nd) along the road, have exploded into a showy ball of white tufted seed.

Along the powerline, an American robin, a Lazuli bunting, a Song sparrow, and a Black-headed grosbeak, all rest in the afternoon sunlight singing loudly. There are several more buntings replying on the western hillside. Further down trail near mile 0.2, two more grosbeaks call from the oaks, and this corresponds to the position where they are heard when along the road.

* * * *

In Thoreau’s “Journal” on June 7th, 1853 he records red clover, buttercups, cinquefoil, blueberries, and huckleberries. He hears quail and sees an oven bird and a night-hawk in its nest. On June 7th, 1854, he notes large sized green berries, blueberries, and choke-cherries. He hears honey bees. He sees a yellow-winged sparrow, a night-hawk, and the first fire-flies of the season. On June 7th, 1858, he observes that wind blowing across grass silences crickets. On June 7th, 1860, white clover has bloomed and he again hears honey-bees.

* * * *

In a June 7th, 2005 letter to the editors of the Salt Lake Tribune, Chuck Tabaracci related the saving of his dog after it had been swept away in the high waters of the canyon’s stream (Salt Lake Tribune). Two women lept into the stream to save the dog and where also swept downstream. All were saved and one woman suffered hypothermia and the second a concussion. Tabaracci also noted that people walking up the road refused to help the women and eventually they were transported to LDS Hospital by ambulance. On June 7th, 1913, the Commercial Club in a report, opposed building a highway up City Creek to connect with Morgan County (Salt Lake Tribune). On June 7th, 1893, City Council President Loofbourow proposed banning all of the new bicycles from the City (Deseret Evening News). He stated that, “I would encourage a movement to send them (all the bicycles) to the head of City Creek canyon and keep them there, as they are an intolerable nuisance” (id). A June 7th, 1887 Salt Lake Herald editorial proposed a system of reservoirs in City Creek Canyon in order to solve a shortage in the City’s water supply.

June 13, 2017

June 6th

Sufficiency and Necessity

5:00 p.m. It is the fourth day of near record heat in the nineties. On the heat of the afternoon, only a few birds are heard: Warbling vireo, Black-headed grosbeak, Song sparrow and American robin. There is one each of this season’s common butterflies: Weidemeyer’s Admiral butterfly, Western tiger swallowtail, Mourning cloak butterfly, and Cabbage white butterfly. Because of the heat, there is no one on the first mile of road, although the parking lot is three-quarters full.

Returning down canyon, an American robin alights in the grass of a picnic site, cocks its head to one side, and then jabs down with its bill to pull out a fat earthworm. It comes and goes in a moment.

* * * *

In Thoreau’s “Journal” on June 6th, 1852, he notes the season’s first dragonflies. On June 6th, 1853, he records pink corydalis and side-saddle flowers, He sees blue-eyed grass, a flower, in meadows, lambkill, and huckleberries. He describes a slippery elm and hears bluebirds singing. He notes that under the summer sun, the ground is drying out and notes which spring flowers have peaked due to lack of water. On June 6th, 1854, he smells locust trees. He sees a viola by a river and examines the shapes of leaves of various trees. He again reports dragonflies and Sphinx moths. On June 6th, 1855, records seeing blue-eyed grass blooming. On June 6th, 1856, he admires that bird’s nests are well constructed. On June 6th, 1857, he notes leaves and grass dominate, i.e. not flowering plants. He notes dwarf dandelions are common. On June 6th, 1860, he notes that undergrowth foliage is becoming dense. At night, he observes bats in the sky and water bugs on a stream.

* * * *

In a 1995 article, Montgomerie of Queen’s University and Weatherhead at Carleton University conducted a series of controlled experiments concerning the most common of human experiences – seeing a robin pull of worm from underneath the ground. How do robins so expertly perform this task? It seems as if they can somehow see beneath the ground to locate their prey. I like their study because it nicely illustrates how proof of causation can be shown in laboratory controlled experiments and how designing such experiment is a difficult art. Such causation proofs are done using bi-directional “if and only if” implication, and such logic problems are the bane of graduate school candidates who sit for standardized entrance exams.

Montgomerie and Weatherhead suspected that robins use either sight, smell, vibrations, sound or some combination of the four to locate underground worms. In their experiments, Montgomerie and Weatherhead measured the success rate of robins finding mealworms in four artificial environments: First, live scent, sound, and vibration emitting mealworms were buried in the same cage as smell emitting but soundless and vibration-less dead worms. Second, robins were placed on a layer of soil that contained a buried cardboard sheet that covered soil containing live mealworms. Thus, the robins could not rely on visual cues to find their prey. Third, they buried mealworms in a vertical soil containing wall of a cage. Thus, the robins could not feel the vibrations of the buried worms. Fourth, they placed robins on soil containing buried live mealworms but used a white noise generator to mask any noises that the worms might make. The robins could find worms in the absence of sight, smell and vibration cues. They had less success when finding buried worms when sounds were masked with white noise (id).

Proving causation by bi-directional “if and only if” implication involves showing that cause implies effect using propositional logic, that is “If a (C)ause exits, then the (E)ffect occurs” or C -> E in symbolic logic. In bi-directional “if and only if”, the (E)ffect must also imply the (C)ause, or E -> C. The C -> E part is usually described using the language that “C is a sufficient cause for E”, and the E -> C part is described using the language “C is a necessary cause for E”. The mathematics of propositional logic tells us that C -> E is the same as not(C and not E). Conversely, E -> C is the same as not(E and not C). Thus, E -> C, sufficient causes and necessary causes can be expressed as an overlapping butterfly Venn diagrams. Draw two overlapping circles and label the left circle “C” for causes and the right “E” for the effect. Sufficient causes are in the left circle, and necessary causes are subsets of the effect and appear within the right circle. Necessary and sufficient causes appear in the overlapping area. All of this confusing propositional logic is normally reduced to two simple tests for the propose of analyzing causation and taking graduate school entrance examinations:

• Sufficient cause test: Any candidate Cause that is present when the Effect is absent is eliminated as a candidate sufficient cause. This is equivalent to not(C and not E) in proposition logic symbolism.

• Necessary cause test: When an Effect is present when a candidate Cause is absent is eliminated as a candidate necessary cause. This is equivalent to not(E and not C) in proposition logic symbolism.

• Necessary and sufficient cause test: Is the intersection of the remaining results after application of previous two tests.

Finding a necessary and sufficient cause is accomplished by building a table of causes and the resulting effect. Eliminate causes that fail either the sufficient or necessary causation test and take the intersection of the two lists. The remaining candidates are sufficient and necessary causes. The proof that those candidates are the cause of the effect is done. This is best illustrated by Pasteur’s experiment that demonstrates that the fermentation of liquids like grape juice and milk was caused by particles in the air and did not arise spontaneously from particles in those liquids. This was Pasteur’s proof of the germ theory of disease.

To prove that particles in the air causes liquids to ferment and not particles in the liquid, Pasteur constructed flasks with a long-thin neck. Potential causes of fermentation are air in the flask, air in the liquid, and air outside the flask. In his first test, he heated the grape juice (or milk) to destroy any bacteria in the milk and the long-neck excluded outside air. The liquid did not ferment. The result where fermentation is absent shows under the sufficient cause test, that neither particles in the liquid or in the flask’s air cause fermentation. That left the air outside the bottle as an untested candidate sufficient cause. In his second test, he again heated the liquid and air inside the flask to kill all bacteria, but then broke off the long neck that excluded outside air. The liquid fermented. This result where fermentation effect is present shows that under the necessary cause test, air outside the flask contains particles that cause fermentation, but not the sterilized air or liquid in the flask. In his third test, Pasteur heated a tilted the flask so liquid filled the long neck, exposing only the liquid to outside air. Fermentation occurred, and under the necessary cause test, this excluded the air inside the flask as a necessary cause of fermentation. The intersection of the candidate sufficient and necessary causes is the air outside the flask. Conversely, fermentation does not occur spontaneously from particles in the air or liquid inside the sterilized flask.

Applying this type of causation proof to how robins find worms, Montgomerie and Weatherhead thought that there were four candidate causes or means by which robins found worms (the effect): smell, vibration, sound or vision, or some combination of the three. The effect is present when birds found the worms and absent when they did not. In their first experiment involving scent, birds were no better at finding dead worms than chance or than finding live worms, and under the sufficient cause test, this eliminated smell as a sufficient cause. The birds did much better than chance in finding live worms using the remaining auditory, visual or vibration cues, but since smell was also present, no candidate cause was eliminated under the necessary causation test. In their second experiment that removed visual cues but left smell, vibrations and sounds, the birds found live worms better than chance. Under the necessary test, eliminated sight as a necessary cause. In their third test involving vibration, birds were still able to find worms when only vibration was removed, and vibration was eliminated as a necessary cause. In their fourth test, birds were unable to find worms when only sound was removed, and smell, vibration, and sight were eliminated as a sufficient causes. The necessary and sufficient results of their four tests can be reorganized as follows:

• Smell – Effect absent – sufficiency test: Smell-possible, Sight-impossible, Vibration-impossible, and Sound-impossible. Result: Smell was eliminated as a candidate sufficient cause.

• Sound – Effect absent – sufficiency test: Smell-possible, Sight-possible Vibration-possible, and Sound-impossible. Result: Smell, Sight and Vibration are eliminated as a candidate sufficient causes. Sound remained as a candidate sufficient cause.

• Sight – Effect present – necessary test: Smell-possible, Sight-impossible, Vibration-possible, and Sound-possible. Result: Only sight was eliminated as a necessary cause.

• Vibration – Effect present – necessary test: Smell-possible, Sight-possible, Vibration-impossible, and Sound-possible. Result: Only vibration was eliminated as a necessary cause.

• Smell – Effect present – necessary test: Smell-possible, Sight-possible, Vibration-possible, and Sound-possible. Result: This test eliminated no candidate necessary causes.

Looking at the intersection of all of these tests, only sound remains as both a sufficient and necessary cause. Thus, Montgomerie and Weatherhead concluded that, “[T]hese results strongly suggest that the robins located buried mealworms and earthworms by using auditory cues (id. at 149). Their conclusion varied from the only similar prior study that concluded that robins use visual cues to find underground worms.

For most questions involving nature (and economics and sociology), causation cannot be shown in controlled experiments, and investigators must rely only on statistical proof of sufficient causal agents. Both necessity and sufficiency can never be shown due to the multiplicity of causal factors, from ethical restraints that prevent the use of controlled experiments, or excessive cost, and proof of causation is relegated to argumentation from signs (April 27th). For such matters we are forced to rely on humanistic-based judgments when issues involving nature and biology have implications for human society. Much of modern political argumentation is based on politicians intentionally citing only one of several candidate sufficient causes, and then questionably ignoring other obvious, likely causal factors in order to fashion a passably convincing position. The only antidote is an educated citizenry armed with critical thinking skills.

When our canyon robin cocked its head to one side today, it was listening for the buried worm.

* * * *

On June 6th, 2009, three-hundred volunteers pulled invasive weeds like myrtle spurge and toadflax from the Morris Reservoir area overlooking City Creek Canyon (Salt Lake Tribune). On June 6th, 1993, the Salt Lake Tribune overviews hiking access points along the Salt Lake Valley, including at Ensign Peak, City Creek Canyon, and the Tomahawk Drive access to Little Twin Peaks in the Avenues. The Tribune notes reductions in hiking access as luxury subdivisions, such as the Turville-Robinson development below Ensign Peak, develop the foothills. Salt Lake City has regulations requiring foothill developers to include access points in their plans. On June 6th, 1905, boxer Jack O’Keefe trained by running up City Creek Canyon (Salt Lake Herald). On June 6, 1904, wildflowers are in full bloom on the foothills and in the canyons (Salt Lake Herald). City Creek has Stansbury’s phlox, that has a purple flower and yellow balsam root (id).

June 5th

Hopping Horsetail Pollen

4:15 p.m. It is the third day of an unusual early heat wave where daytime maximum temperatures reach 95 degrees Fahrenheit, while the average maximum for early June is about 80 degrees. In the heat, fewer birds sing. There is one Warbling vireo near picnic site 1 and a single Black-headed grosbeak and a few Song sparrows below milepost 0.5. On this Monday, people follow suit: the heat deters them and there are only a few runners and walkers along the road. Despite the heat and yesterday’s end of canyon snowmelt, the stream still runs high. But at mile 0.6, there is a distinct thermocline: a breeze picks up and temperatures are ten or fifteen degrees lower than in the city. The birds respond accordingly.

The season’s first unambiguous Weidemeyer’s Admiral butterfly (Limenitis weidemeyeri latifascia), a black butterfly with white wing bars, floats by at milepost 1.0, and this followed by a Blue dasher dragonfly. A new white butterfly is seen, but it is too fast and appears too briefly to identify. Two dead brown moths are found at different places along the road that have delicate yellow-orange underwings. They are invasive Large yellow underwing moths (Noctua pronuba).

The heat has also begun to force Wood roses along the road. As they reach maturity, their color starts to lighten, and a day or two later, their blossoms shrivel. More are gone at the lower canyon, the wave of mature roses is slowly moving up canyon. The blossoms of the Solomon’s seal field in the cattail seep at mile 0.7 have shriveled and passed. Across the road, the beginnings of Milk weed plants rise to a foot tall. New crops of horsetails have matured between mile 0.4 and mile 0.8, and they can be distinguished from the still reawakening horsetails that overwintered. These new horsetails are larger in diameter, have a lighter green color, and have larger cone shaped heads. Older horsetails are a darker green, and for the most part, their heads from not yet swelled with pollen for this new spring. On close inspection, the newer horsetail heads release a puff of pollen when disturbed.

Turning down canyon from Pleasant Valley, below the Red Bridge near mile 0.9, an orb weaver spider has woven a large four-foot circular web suspended between boulders and surrounding tree branches. Some of the web’s silken, supporting suspension cables reach six feet over the stream. The web whips wildly in each breeze, but it is effective. The spider has bundled up several insects along its web’s radial branches.

* * * *

In Thoreau’s “Journal” on June 5th, 1850, he smells that the air is full of spicy odors. He sees lady’s slippers and wild pink plants. On June 5th, 1852, he records cinquefoils, and he notes that lupines are in full bloom. On June 3rd, 1853, he again notes that the air is full of fragrance and that meadows are full of sorrel and green grasses. On June 5th, 1853, he sees a pair of nighthawks and their nest, and a blackbird. On June 5th, 1855, he notes sedge grass growing in rock cracks. On June 5th, 1856, he records lady slippers and he examines a cuckoo’s nest.

* * * *

In 2013, Marmottant, Ponomarenko and Bienaimé at the University of Grenoble reported that the 50 micrometer pollen of horsetails have the ability to “walk” (Marmottant, Ponomarenko and Bienaimé 2013). These tiny pollen are shaped like harlequin starfish, except they have four arms instead of a starfish’s five. When wet, the arms of the pollen curl around its central body. As the pollen dries, the arms suddenly unfold and propel the pollen into the air, and once aloft, it can be deposited in a more favorable, moist habitat (id).

* * * *

On or about June 5, 1975, Utah’s first gay pride festival, then called “Gay Freedom Day” was held in Memory Grove at City Creek Canyon (Salt Lake Tribune, June 5, 2008). A small crowd of 300 gathered over beer, burgers and hotdogs. Then they moved to the Sun Tavern. One of the participants of the first festival recalled that people were afraid to attend because they were concerned that bosses, co-workers or neighbors might see them attending. “We knew we were being discriminated against, and it was at least up to us to stop discriminating against ourselves,” the first pride day participant noted.

June 4th

End of the Snowmelt

7:00 p.m. Temperatures reach 97 degrees today; one degree short of a record. As a consequence, the SNOTEL station at Louis Meadows records that all of the snowpack at near mile 7.0 of the canyon is gone. This is a seasonal milestone, and from now to next October 1st, the stream will flow only from rainfall and water stored underground. This afternoon, clouds stream in from the west, but it is too hot for the rain, which falls in curtains from a thousand feet overhead, to reach the ground.

Birds are quiet in this later evening, but still a single Blacked-head grosbeak is seen and heard near mile 0.2. A single House sparrow and a Chirping sparrow are also heard along the first mile road. Later, returning down canyon, I am for the first time able to see and hear the grosbeak performing a call with three low notes followed by a trill. This is a common call heard in the first canyon mile, but it does not appear in my reference recordings for this grosbeak. Other songs and calls for this grosbeak are in the reference recording. Butterflies are also subdued in the evening. There are single instances of a Mourning cloak, a Cabbage white and a Western tiger swallowtail. Gnats are rising in the heat.

* * * *

In Thoreau’s “Journal” on June 4th, 1852, he hears birds singing at dawn and he sees that dandelions have gone to seed. On June 4th, 1853, crickets are singing at noon. He examines oak and chokeberry leaves. On June 4th, 1855, white and red clover are blossoming, and mosquitoes are rising. On June 4th, 1857, he notes “earth-song,” or the combination of the sounds of insects and birds as a sign of summer. On June 4th, 1860, he notes elm trees are in full foliage, and that warblers have left for the season. Buttercups are in bloom. He sees a cat bird.

* * * *

How much water is stored in the east and west halves of the Salt Lake salient (may 14th) that drain into the stream? Using the difference between stream flow data taken at the canyon’s water treatment plant from 1950 to the present and precipitation records from the Louis Meadow SNOTEL station for 2000 to the present, I am able to make a rough estimate of the lower bound of stream flow that comes solely from underground reservoirs. For two months each year – June and July, average stream flow exceeds average precipitation. In June, the average stream flow exceeds rainfall by about 318 acre feet, and in July, the stream flow exceeds rain by about 242 acre feet, for a mean underground flow into the stream of 280 acre feet per month. This 280 acre feet per month is the lower bound. Summer rainfall will evaporate and never reach the stream or recharge underground aquifers. Depending on underground geologic structures, all of the water that falls within the 19.2 square miles of the canyon may not flow towards the stream. The oak and fir forests and grasses consume considerable quantities of rain water, and those withdrawals are not included in the sum of the difference between inflows and outflows. Thus, the true amount flowing into the stream from underground aquifers could be two or three times the lower bound of 280 acre feet per month. The 280 acre feet of water each month is enough to flood 28 of the city’s 10 acres blocks with a foot of water. The volume of that water is about 12.2 million cubic feet of water (0.000083 cubic miles), or a cube about 230 feet on a side. In contrast, the Mormon Temple that sits at the heart of City Creek Canyon’s delta (March 10th and March 12th) is 288 feet tall.

The lower bound of 280 acre feet of underground storage is a reasonable estimate. Treating the 12 miles of the Salt Lake Salient as two inward facing right-triangles that are 1.25 miles from the stream to ridgeline, the volume of the salient that drains towards the stream is about 32.5 cubic miles. The 0.000083 cubic miles of underground water flow is only 9 of 10,000,000ths of the salient’s volume. That water can easily fit in the pores space between the salient’s rocks.

* * * *

On June 4th, 1934, University of Utah Engineering Professor F. W. Muir reported that tree rings taken from City Creek Canyon and near Brighton show that in the last 300 years, there have been many drought cycles (Salt Lake Telegram). On June 4th, 1914, the City acquired 80 acres of private land in City Creek (Salt Lake Telegram). On June 4th, 1910, Land and Water Commissioner Frank Mathews reported that green caterpillars, possibly one million, are moving down City Creek Canyon defoliating (“stripping bare”) the trees (Salt Lake Telegram). On June 4th, 1906, streets in Salt Lake City principally from 300 West to 800 West, were severely flooded (Salt Lake Telegram).

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