City Creek Nature Notes – Salt Lake City

March 12, 2017

March 11th

Filed under: Birds, Colors, cut-off to trail at mile 0.6, Geology, Lichen, moss, Moth — canopus56 @ 3:23 am

City Creek’s Delta – Part II

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Flood sandbag river down Main Street in 1983 (left, KUTV News) and the 1906 flood where the sandbag river was sent down Third West (right, Utah State Historical Society, Utah Digital Archives, Marriott Library). Ensign Peak and the State Capitol Building are in the far background.

5:00 p.m. Again, a late run up the canyon. Since it is a Saturday night and it temperature rose into the sixties today, the parking lot is overflowing and the road is frequented by couples strolling arm-in-arm or hand-in-hand. Below picnic site 7, I look for the source of the intermittent spring on the west side of the road, and about seventy-five feet from the road, there is a small pool about 15 square feet in size and one foot deep that is the source of the rivulet seen today and yesterday. Air bubbles up the middle of the pool, and I make a note to revisit this site as spring progresses. Three moths, that move to fast to be identified, float by. At mile 1.1, I again hear a warbling twilight bird call in a gully to the west, and I decide to jog down the Pipeline Trail to see if it can be located. The bird is still unseen, but as I am going down the trail near mile 0.8, I come across a rock outcropping that previously had confused me as to whether it was volcanic breccia (January 7th). In better light and without snow, I can see that this is a sedimentary outcrop, but the rock is covered in a dark black lichen that is spotted with a second cream colored lichen with a light blue tint. The rock also has sparse moss and orange lichen colonies. The black lichen makes the rock look igneous. I jog down to the Shark Fin Rock at mile 0.5 and go down the cut-off and back to the road. The track is muddy, and amongst the many dog tracks, there is one unmistakable hoof print of a mule deer.

The first diversion of City Creek waters occurred on August 2, 1847, when fifteen members of Young’s reconnaissance party built a dam to divert the west branch of City Creek to what is now Pioneer Park at 300 South and 300 West (Hooten; Bancroft 261). First, they split the diversion into two streams on either side of their first encampment and later the first stockade (Hooten, 6-7). As previously noted, the east branch of City Creek went to 300 South and 500 East before turning back west and the Jordan River. Later, City Creek was channeled into two branches: one going west to the present Union Pacific Station and one going south to the location of the current City and County Building (Hooten, 3). On August 22nd, 1847, the pioneers named the creek “City Creek” (Hooten, 7).

When settling on a final grid design for their new city, the pioneers made a practical choice to locate their commercial center on the centerline of City Creek’s delta, but that choice left the heart of the city vulnerable to future flooding. The natural parabolic curve of City Creek’s delta lent itself to gravity feeding water to flat lands to the east and west of the delta. This left the north-south line along the delta itself as the obvious choice for the new city’s administrative and commercial center. This was a reasonable decision. Many cities in the east were laid out on either side of waterways that in the east provided both transportation and water power. Through the central district, City Creek was re-channeled down First East Street, now State Street, and the pioneers quickly moved to establish a water-powered adobe mill to build their first homes and grain (grist) mills along the City Creek. They built four water-powered lumber mills in the canyon to supply wood for constructing homes (Day; Watson). However, because of the pioneer’s eastern United States’ bias (Feb. 6th), they did not appreciate how City Creek was subject to highly variable flows and extreme flow events. In the 1850s, initial colonists were of the opinion that the arid Utah valleys were free from flooding (Honker 1994 at 21) and that their resource harvesting activities would not increase flooding (Park). That the pioneers perceived the landscape as arid with little rain or snow is evidence by their choice to build their initial fort with flat roofs, which promptly leaked the following spring (Bancroft, 277).

But their understandable impression of the potential for flooding was incorrect, and new research suggests that much larger flood events in City Creek can occur. In 2014, when Bekker et al reconstructed Utah extreme weather events back to 1492 from tree rings (Feb. 9th), they estimated the number of extreme floods as wells as extreme droughts. Although drought was far more prevalent since 1500 as compared to the modern era after 1850, those droughts also have been punctuated by years of extreme precipitation. Most Utahans will remember the flood of 1983 and the winter of 1993 as peak wet years. Those years did not make the list of Bekker et al’s 5th percentile wettest years since 1492. In the 1900s, 1907 and 1965 were more severe (Bekker et al, Table 3). Since 1500, there have been twenty-two years with more extreme precipitation than 1983. It is these extreme wet events that pose a hazard to City Creek’s delta and the business district.

In Thoreau’s “Journal” on March 11th, 1854, he hears four types of bird songs: bluebirds, song-sparrows, chickadees, and blackbirds. Where snow has melted, he sees the dens of mice. On March 11, 1855, he sees bleached pine needles. On March 11, 1860, he finds a woodchuck burrow. He is approached by two red squirrels. On March 11, 1861, he examines willow seeds. (The willow has a tiny air-dispersed seed suspended below a white cotton tuft.)

On March 11th, 1905, two prisoners in the chain gang working on City Creek road escaped (Salt Lake Tribune).

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