Where does our water come from?
Grinnell sources a majority of its piped water from the Cambrian-Ordovician Sandstone Aquifer. This water source is considered a renewable resource if the rate of consumption is less than or equal to the rate of renewal. Unfortunately, the current rate of consumption is much higher than the rate of renewal. In response to the decline in aquifer water level, the Jordan Aquifer Rule was developed. This rule involves higher regulation of the Cambrian-Ordovician Sandstone Aquifer and requires high-volume consumers to submit and implement a usage reduction plan.
As of 2018, Poweshiek County uses 380 million gallons of water from the aquifer annually. Yes, that is a big number. However, because of interventions by the county and Grinnell College, Poweshiek County decreased its annual consumption by 19 million gallons annually (comparing consumption in 2014 to 2018). Poweshiek County is not alone; 31 of the 54 counties in Iowa that use the aquifer have decreased their annual withdrawals from the aquifer since 2014.
How is our water consumed?
As noted in the Grinnell College Sustainability Plan (2013), water usage in student residences accounted for a third, the largest proportion, of the total campus water usage in 2010. More than a decade later, how has the overall usage and proportional consumption changed?
According to the most recent data, student housing, on average, uses 7.7 percent of the total campus water consumption. Student water use in residence halls and other student residences has decreased since 2013, as has usage in athletic buildings, academic offices, and the natatorium. These decreases in water use are primarily attributable to innovative construction and sustainable designs.
By following the Landscape Master Plan, architects and landscapers have implemented structures and designs that minimize runoff and increase native species. The implementation of rain gardens, bioswales, green roofs, and permeable pavers has been instrumental in reducing the stormwater runoff and conserving water. In addition to minimizing runoff, Grinnell College collects rainfall in a cistern. This allows the College to pump less water from the Cambrian-Ordovician Sandstone Aquifer.
How do we track water use?
The exodus of students from campus during the COVID-19 pandemic allowed the Sustainability Committee to analyze the impact students have on the College’s water consumption. Surprisingly, the data show that students are not the major drivers of water consumption. For example, during the pandemic when classes were primarily online, water usage in academic buildings only decreased by 23 percent compared to the previous term. Students make the largest impact on water usage in their living quarters; nonetheless, during the pandemic, water consumption decreased by 68% in the residence halls and project houses.
In reality, students and their everyday actions have a very small impact on campus water consumption. For this very important and now quantifiable assertion, Grinnell College has started to heavily invest in sustainably-focused architectural firms and landscapers that respect and understand prairie ecology. The sustainable aspects of newer buildings and spaces will help our campus conserve much more water than smaller, student-body-based initiatives.