Prior Appropriations Water Rights Lab (Water in the West)

This Excel-based educational resource is designed as a week-long module targeting sophomore-level students in Boise State University's Water in the West course (GEOS 212). At the end of this module, students should be able to accomplish the following: (1) list some consumptive uses of water, (2) articulate the principle of Prior Appropriation, (3) in the context of water rights, describe what curtailment is, (4) translate water rights information into a schedule of diversions, (5) simulate the effect of water withdrawals on a streamflow hydrograph, and (6) develop a report as a member of a team.The lab requires the students to adopt the perspective of a water manager who is tasked with implementing a set water withdrawals from a notional river in the Western US in accordance with a Prior Appropriation approach. They are provided water rights information for five water users that include: (1) a priority date, (2) a date of first use, (3) a date of final use, and (4) an authorized diversion rate. They then have to manage withdrawals (i.e., the timing of curtailment) from the river in accordance with these water rights under three scenarios. The first scenario considers a historical era in which seasonal snowpacks maintained water well into the growing season. The second scenario requires them to undertake curtailments in accordance with priority date to maintain flow in the river due to earlier and more rapid snowmelt associated with climate change. The final scenario provides them a simple storage reservoir to which they can divert water and from which they can withdraw water to sustain late season water use.