Order Description
Water Science and the Environment – HWR 201 – Spring 2016
Homework 1
Distributed: 28 January 2016
Due: 9 February 2016, in class
Precipitation on Mount Lemmon vs. stream flow at Sabino Canyon Dam
Problem 1.
We will look at how stream flow at Sabino Canyon Dam in the Catalina Foothills, Tucson, AZ
relates to rainfall on Mount Lemmon and at Sabino Canyon Dam. The conceptual model is simple:
Sabino Creek at Sabino Dam is the outlet of all streams that drain the Mount Lemmon watershed
on its south side. Thus, rainfall on Mount Lemmon plus that at Sabino Dam should be
reflected in the Sabino Creek level at Sabino Creek Dam.
Download the data from the three sources below. Include the data from the summer 2015, July 1,
2015 to October 1, 2015.
1. Rain gauge at Mount Lemmon – measures amount of rain at Mount Lemmon: https://
alert.rfcd.pima.gov/perl/pima.pl
2. Rain gauge at Sabino Creek – measures amount of rain at Sabino Creek: https://
alert.rfcd.pima.gov/perl/pima.pl
3. Stream gauge at Sabino Creek Dam – measures water level in Sabino Creek: https://waterdata.usgs.gov/az/nwis/uv?site_no=09484000
Required:
(a) Make a sketch (map or cross-section) showing the hydrological situation. Show water flowing
from Mount Lemmon to Sabino Creek Dam.
(b) Plot these data on three separate graphs.
(c) Identify the peaks in precipitation on Mount Lemmon (item 1 above) and match them with
peaks in stream water level at Sabino Creek Dam (item 3 above). What is the time difference
between corresponding peaks? In other words, how much later do stream water levels rise following
precipitation events on Mount Lemmon?
(d) Separately, look at the correlation between local rainfall at Sabino Creek (item 2 above) with
peaks in stream water also at Sabino Creek (item 3 above). How is this correlation different
from that in part b above?