Fitting a local arroyo into the Tucson Basin
Through field studies, hands-on experiments, and exercises using maps,
photos and discharge data from the Tucson Basin, students explore how
water flows through Tucson
- Map skills (elevation, scale, Tucson geography).
- Drainage networks and basins concepts and practice.
- Data analysis and graphical interpretation: precipitation and discharge.
- Connect local water and development phenomena in DVHS to those in
the greater Tucson Basin.
- Field studies, linking observations to process.
- Writing skills.
- PowerPoint, Excel, Web, GPS skills.
- Scientific method.
- Organizational skills (develop portfolio over the whole project).
Students prepare a guide to the DVHS arroyo using information they gather
from their own fieldwork and from the other Tucson waterways activities
completed. Each group is responsible for writing an arroyo guide, with
group members becoming specialists on different features of the arroyo:
vegetation, water flow, sediment and shape. All arroyo guides will contain
descriptions of the following: the four arroyo features, the arroyo's
role in the rest of the Tucson surface water system and changes in the
gully through time. The guides can be posted on the web, turned into posters,
made into pamphlets or any other presentation media that is appropriate.
Activity 1 Getting oriented
An introduction to the Tucson Basin and map reading
Students use 1 x 2 (1:250,000) maps of the Tucson and Nogales regions to gain familiarity with map coordinates, contour lines, map scale and Tucson geography.
Activity 2 Investigating how water moves through Tucson
Students use aerial photographs and overlays of the Santa Cruz River Basin to identify drainage basins, rank channels (by catchment area, size and vegetation), calculate gradient and determine the direction of water flow.
Exercise that requires students to find locations and elevations on map, convert map distances to actual distances and calculate gradient.
Activity 3 Data Diving
Students use precipitation and stream gage data from the Santa Cruz River to determine the relationship between precipitation, discharge and position along a channel profile. Each student in a group is responsible for plotting and analyzing data from one stream gage along the Santa Cruz. Each student creates a channel profile that includes all gaging stations and the group compares results from each gaging station.
Students review surface water concepts and map skills. To be done individually within one time period. Students need not know any facts going into this exercise, but need to be comfortable with the mapping and surface water concepts. The exercise will ask students to locate coordinates on a map, find the distances between points, calculate gradient, identify the direction of water flow, outline a specific drainage basin, and predict the relative difference in discharge between two points along a channel.
Activity 4 Stream tables
Students build stream tables and explore the effects of slope and discharge on channel shape, water speed and bank stability. This exercise emphasizes hypothesis testing and requires students to review their stream table experiments in light of the scientific method.
Activity 5 DVHS campus through time
Students put their high school on the map to understand how the wash behind campus fits into the greater Tucson drainage network. Students investigate changes in the wash and their campus over the past 50 years by studying 6 aerial photographs spaced at 10-year intervals.
Parts of this activity can be used as a pre- and post-assessment.
Unit 2 The Santa Cruz, Tucson's changing river
- Gain familiarity with the geography and history of the Santa Cruz
- Recognize the dynamic change in Tucson over the last 100 year and
the things that drive it.
- Apply field and map skills learned in Unit 1.
- Start to develop a personal identification with some aspect of change
- Research a current (environmental/development) issue and develop
a plan to effect change in a way they see fit.
Activity 1 Same place different time
Students examine time-lapsed photo sets of Silver Lake, the Santa Cruz and downtown Tucson. They mark the similarities and differences, and suggest possible explanations for the differences.
- Silver Lake
- The Santa Cruz from A Mountain
- Downtown Tucson
- Santa Cruz River
Activity 2 The Santa Cruz flow
Students examine discharge data from 4 gaging stations on the Santa Cruz River (Nogales to Marana) and explore how the flow changes over its course. Students develop possible explanations for these changes and formulate ideas for how these changes would be evident at each gaging station. Students plot the gaging stations on the large-scale maps and draw channel profiles.
USGS gage data for all Pima County sites
USGS gage data for all Santa Cruz County sites
Activity 3 Santa Cruz field investigation
On separate trips, groups of students from the class visit the four gaging stations along the Santa Cruz, collecting data on the vegetation, channel shape, type of sediment and development. Each student writes a report describing his/her observations of the Santa Cruz gaging station location that he/she visited. After all of the stations have been visited, the students present their observations to the class and compare their findings between stations, matching them to the expected differences from Activity
Activity 4 Personal interviews
Students interview a family member or friend who has lived in Tucson over 50 years about change in Tucson, with specific attention to water and development. The student repeats the interview process with someone who lives in Tucson <20 years and then answers his/her own interview questions about change.
Activity 5 Santa Cruz and Tucson timeline
Students use information that they have assembled in addition to information from a fact sheet to create a time line of Tucson and the Santa Cruz over the past century. The time line will include photographs, graphed data, facts about the development of Tucson, personal information about the memories and events in their family's history (with respect to Tucson).
Activity 6 Research Project
Students pick a specific development issue in Tucson and in a paper/presentation define the issue and present a way to address it. Students will do some research on the project but will rely on much of the information that they gather over the course of the 2 units. The project uses a structured format to develop an argument by defining an issue, presenting the facts (past, present and future), and proposing a solution.