City Creek Nature Notes – Salt Lake City

February 26, 2017

February 24th

Filed under: Venus, Weather — canopus56 @ 9:21 pm

Seeing Flood and Drought Years

External Link to Image

Source: Harris 1942 at p. 53.

5:30 p.m. The canyon recovers slowly from yesterday’s storm and the abrupt turn back into winter. No birds are heard or seen. All has returned to frozen sleep. People are gone because of this echo in low temperatures, and once again, I have the canyon to myself. With the breath of spring earlier this weak, my body rebels against the cold. Although temperatures are not as low as in early January, it feels colder, and this illustrates how cold is as much as matter of perception as fact. Brilliant Venus, which a month ago was centered on the road while jogging down-canyon at dusk, now shines in the southwest sky as it out-runs the Earth on another turn around the Sun.

Such daily large variations between drought and heavy precipitation and heat and cold repeat in Utah’s and the canyon’s annual weather patterns. For the nine years between 1869 and 1877, City Creek flooded the city four times. There is a tree stump in picnic site 3. The original tree was perhaps a cottonwood. Examining and photographing the stump, I notice a pattern in the rings. A wider set of rings is bracketed by two sets of smaller spaced rings. The Wasatch Front Mountains and its valleys are an arid, drought region that are punctuated by years of extreme precipitation, snowfall and spring flooding. Weather records show a series of peak snow years followed by City Creek flooding the city. Perhaps the wider rings correspond to those wet years near 1870.

With respect to these drought and flood cycles, An old report summarizing the first one-hundred years of the Metropolitan Water District of Salt Lake City contains a graph that records these widely varying annual fluctuations between drought and flood. (Harris at p. 53, “Relation between Water Development and Population and Precipitation”). The graph illustrates how the growth of population, droughts and floods relate to plans and improvements to increase utilization of the canyon’s water. A twelve year oscillation between drought and flood, coupled with increasing population, drove the City’s expansion of water infrastructure between 1874 and 1942. An initial Euro-American colonist population in 1850 of 5,000 caused the first utilization of City Creek as a stream fed water source that ran as two ditches on the either side of Main Street (id, p. 4). After a flood cycle and a drought cycle ending in 1880 and a population increase to 20,000, the City brought water from Utah Lake via the 20 mile long Jordan Canal and it built initial holding tanks in and improved the stream channel of the City Creek to increase its flows. In 1890, after years of extended drought and a population expansion to 40,000,the City to built a reservoir in Parley’s Canyon at Sentinel Rock and drilled tunnels in City Creek to increase the flow from springs. After the next flood and drought cycle ending around 1900 coupled with a population increase to 50,000, the City obtained more water rights from Big and Little Cottonwood Canyon. After floods ending in 1910, an extended drought through 1915 and a population increase to 110,000, the City built reservoirs in Big and Little Cottonwood Canyons and the 5,000,000 gallon reservoir at Pleasant Valley of City Creek Canyon. After a flood cycle in the 1920s and a severe drought in the 1930s, together with a population increase to 150,000, the City formed a regional water district and began construction of a massive water reservoir system on the eastern or backside of the Wasatch Front Mountain Range. Water was transported between hydrologic basins through a series of underground tunnels, some as long as 12 miles.

Other drought cycles in the 1960s and 1970s, along with legal water rights concerns, gave birth to the Utah Central Project – a billion dollar series of dams and underground diversion tunnels from the Unita Basin about one-hundred miles away and the expansion of the Deer Creek reservoir and construction of the Jordanelle Dam. The Utah Central Project started delivering about 120,000 more acre-feet of water to Salt Lake County in 2007. The delivery of more water resulted in a massive construction boom on less expensive land in Salt Lake County that continues until today, and from 2014 to 2017, that construction boom has penetrated Salt Lake City limits in the form of box-like, high-density apartments. The increased population resulted in higher use of the canyon for hiking, running and bicycling that I have seen this season.

In Thoreau’s “Journal” on February 24th, 1854, he observes nuthatches, chickadees, and partridges. The partridges are feeding on lambkill shoots and blueberry bushes. On February 24th, 1857 he sees bluebirds and skunk tracks. On February 24th, 1858, he examines colors in the bark of the barberry bush.

November 30, 2016

November 29th

Scrub Oak Forest With Snow

4:30 p.m. The day after a major storm, the road is clear and dry or damp, and the canyon is covered in six inches of new snow. In the high mountains, three feet has fallen. Although the Sun comes out in the afternoon, the temperatures in the canyon remain in the upper twenties and low thirties, and as a result, branches in the scrub oak forest is covered in three to five inches of snow. But because of the low temperature, the snow will not melt. At mile 1.0 on the high north-west ridge, are four female deer and at mile 1.3, six mule deer are digging through the snow for grass hidden underneath. In the distance, the pine and fir trees on Black Mountain and the unnamed peak at 8283 feet have been blasted and are frosted with a layer of fresh snow.

Since the Pipeline Trail is covered with fresh dry snow, I decide to return by jogging down the trail before rising temperatures turn it into watery mud. Three or four other runners have already broken trail, but there is enough fresh snow that I get to enjoy the soft sound of a few inches of powder under my feet. It is slow going, but is still an enjoyable jog. The Gambel’s oaks arch from the left and the right over the trail, meeting at the top, and thus, they form a natural snow covered arch in the dimming twilight. By taking the trail, I am rewarded with the evening calls of a group of chukars (Alectoris chukar) high on the north-west canyon wall.

A third of a mile before the gate, I am greeted by clear skies and a brilliant Venus hanging as a guide star above the trail and twenty degrees above the horizon against a deep blue twilight sky. It will continue rising in the evening sky until its maximum elongation from the Sun and a peak brightness of magnitude -5.1 on January 12, 2017. This is midway in brightness between the brightest star, Vega (magnitude 0.0), and the full Moon (magnitude -10). I am reminded that although my feet are comfortably chilled by jogging through snow powder, on Venus the high level of carbon dioxide in the atmosphere has raised temperatures to where lead flows like water.

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