Event Title

Assessing the environmental benefits and impacts of Red Butte Garden on Red Butte Creek

Presenter Information

Zachary Magdol
Christine Pomeroy

Location

Eccles Conference Center

Event Website

http://water.usu.edu

Start Date

1-4-2014 12:20 PM

End Date

1-4-2014 12:40 PM

Description

Red Butte Garden is located on the University of Utah campus in Salt Lake City, UT. It is a non-profit arboretum and botanical garden. Red Butte Creek runs through the Garden as it transitions from a mainly undeveloped to an urbanized watershed. This study investigates some of the environmental benefits and impacts of the Garden on Red Butte Creek. In late August 2013, riparian Box elder (Acer negundo) foliage samples were collected upstream, downstream and within the Garden. The natural abundance of total leaf nitrogen isotope ratio was determined to assess nitrogen (N) sources and extent of fertilizer influence downstream. Red Butte Creek water was sampled biweekly from September through December 2013 (total of 7 sampling events) upstream, downstream, and within the Garden. Water samples were analyzed for ammonium, nitrate, chloride, orthophosphate, and dissolved oxygen (DO) concentrations as well as temperature and pH. Total suspended solids (TSS) was measured in Red Butte Creek upstream, downstream, and within the Garden at two flow rates, 0.8 and 1.1 cfs. The mean total leaf nitrogen del-15N downstream (1.4 ‰) of the Garden is significantly (p=0.03) higher than the upstream mean (-0.1 ‰). Leaf del-15N in the Garden ranged from -0.2 to 6.7 ‰ (µ=2.7 ‰) and is significantly higher than upstream (p=0.02). The mean C:N ratio of leaves upstream, downstream, and within the Garden is 28.8, 20.7, and 20.0 respectively. Both the Garden and downstream leaves are significantly higher than upstream (p?0.05). There was no statistical difference between mean upstream and downstream ammonium (p=0.95) and nitrate (p=0.32) concentrations. Orthophosphate was below the laboratory reporting limit (0.5 mg/l) for every sample. Average chloride concentrations were slightly higher downstream (14.43 mg/l upstream and 14.62 mg/l downstream) though not significantly (p=0.59). TSS concentrations in Red Butte Creek upstream, downstream, and within the Garden were measured three times throughout this experiment. The average TSS concentration upstream, downstream and within the Garden is 4.33, 17.47, and 13.35 mg/l, respectively. The results indicate 15N enrichment in Garden and downstream leaves which is likely caused by the use of organic fertilizer, fish activity, or net N losses. The leaf C:N is higher within the Garden and downstream than upstream but the source of this increased N cannot be directly associated with Garden activity because of the multiple non-point contributors (e.g., urbanization). Ammonium and nitrate concentrations up- and downstream show no change in stream water quality. Overall, the Garden has little impact to Red Butte Creek and is an example of sustainable landscape management.

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Apr 1st, 12:20 PM Apr 1st, 12:40 PM

Assessing the environmental benefits and impacts of Red Butte Garden on Red Butte Creek

Eccles Conference Center

Red Butte Garden is located on the University of Utah campus in Salt Lake City, UT. It is a non-profit arboretum and botanical garden. Red Butte Creek runs through the Garden as it transitions from a mainly undeveloped to an urbanized watershed. This study investigates some of the environmental benefits and impacts of the Garden on Red Butte Creek. In late August 2013, riparian Box elder (Acer negundo) foliage samples were collected upstream, downstream and within the Garden. The natural abundance of total leaf nitrogen isotope ratio was determined to assess nitrogen (N) sources and extent of fertilizer influence downstream. Red Butte Creek water was sampled biweekly from September through December 2013 (total of 7 sampling events) upstream, downstream, and within the Garden. Water samples were analyzed for ammonium, nitrate, chloride, orthophosphate, and dissolved oxygen (DO) concentrations as well as temperature and pH. Total suspended solids (TSS) was measured in Red Butte Creek upstream, downstream, and within the Garden at two flow rates, 0.8 and 1.1 cfs. The mean total leaf nitrogen del-15N downstream (1.4 ‰) of the Garden is significantly (p=0.03) higher than the upstream mean (-0.1 ‰). Leaf del-15N in the Garden ranged from -0.2 to 6.7 ‰ (µ=2.7 ‰) and is significantly higher than upstream (p=0.02). The mean C:N ratio of leaves upstream, downstream, and within the Garden is 28.8, 20.7, and 20.0 respectively. Both the Garden and downstream leaves are significantly higher than upstream (p?0.05). There was no statistical difference between mean upstream and downstream ammonium (p=0.95) and nitrate (p=0.32) concentrations. Orthophosphate was below the laboratory reporting limit (0.5 mg/l) for every sample. Average chloride concentrations were slightly higher downstream (14.43 mg/l upstream and 14.62 mg/l downstream) though not significantly (p=0.59). TSS concentrations in Red Butte Creek upstream, downstream, and within the Garden were measured three times throughout this experiment. The average TSS concentration upstream, downstream and within the Garden is 4.33, 17.47, and 13.35 mg/l, respectively. The results indicate 15N enrichment in Garden and downstream leaves which is likely caused by the use of organic fertilizer, fish activity, or net N losses. The leaf C:N is higher within the Garden and downstream than upstream but the source of this increased N cannot be directly associated with Garden activity because of the multiple non-point contributors (e.g., urbanization). Ammonium and nitrate concentrations up- and downstream show no change in stream water quality. Overall, the Garden has little impact to Red Butte Creek and is an example of sustainable landscape management.

http://digitalcommons.usu.edu/runoff/2014/2014Abstracts/19