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Students Design Rainwater Collection Systems

Dr. Tom Krueger in the Kinsolving Herb Garden which is receiving one of the rainwater systems.

Dr. Tom Krueger in the Kinsolving Herb Garden which is receiving one of the rainwater systems.

AUSTIN, TEXAS—June 13, 2013

Dr. Tom Krueger, who teaches the first engineering graphics class that civil engineering students take (ME 210), likes to make his class assignments relevant to real world problems whenever possible. This required course, offered only in the Mechanical Engineering Department, has similar courses offered for mechanical and aerospace engineering students, but the assignments vary depending on the student's major. The students learn engineering drafting techniques as well as 3D modeling as they learn to use the engineering software modeling program SolidWorks for Mechanical and Aerospace Engineers, and AutoCAD, and Inventor for Civil Engineers.

Floyld Hoeltling, the Director of Housing and Food Service for the university, spoke to Dr. Krueger's class in February to explain the rainwater collection project to the students.

Floyld Hoeltling, the Director of Housing and Food Service for the university, spoke to Dr. Krueger's class in February to explain the rainwater collection project to the students.

This spring, Krueger and his students worked with the university's Division of Housing and Food services, to design two rainwater collection systems for food and herb gardens, also to be used for teaching sustainability, at two campus dormitories, Kinsolving and Brackenridge. Krueger had six teams of students in his class, with three assigned to each project. The students were tasked with working with the "clients" to determine exact needs, then measuring and making 3D models of the buildings and tanks in order to gain a clear understanding of the roof line design that would provide the runoff water. The students had to determine the size, placement and design of tanks to be used, based on average rainfall in Austin and the amount of runoff from the roofs. The teams on each project were in competition, with the winning design(s) currently being implemented.

Both garden areas need to have a self-sustaining water supply. The Kinsolving garden, for example, uses 300 gallons of water a week. For the teams in the Civil—ME 210 Graphics course, the assignment offered them the opportunity to learn through a practical application of civil engineering. In conversations with Floyd Hoelting the Director of Housing and Food Services; Scott Meyer the Director of Food Services; Robert Mayberry the Chef at Jester; and Greg Moore the Special Projects Manager at Kinsolving Dining Hall, (see all) the criteria were established for the project. In consultation with the personnel in the Housing and Food Services Division, the teams were required to do the following:

  • Measure the existing and proposed garden beds to determine the amount of water they would require if they needed an inch of water per square foot per week.
  • Determine the square footage of roof area from which to collect water. (Floor plans were obtained from the Physical Plant.)
  • Determine the average yearly rainfall for the Austin area.
  • Calculate the amount of water generated per square foot per inch of rain.
  • Calculate the amount of water 1 inch of rain produces on the chosen roof area.
  • Specify the size of a tank to hold a three-month supply of run-off for the roof area chosen.
View of the Kinsolving gardens and patio from the roof. The water tank shown is not what the student's designed. It is an older tank that is being replaced because it doesn't function properly now.

View of the Kinsolving gardens and patio from the roof. The water tank shown is not what the student's designed. It is an older tank that is being replaced because it doesn't function properly now.

The teams toured the facilities, took their own measurements, and architectural drawings were provided. The students made 3D models of the buildings to help visualize the properties and the roof construction. In addition, the teams submitted a written report to be reviewed by their clients. The clients read all the reports and are now in the process of building the rainwater collection systems, although they didn't end up selecting a clear winning team, but incorporating different aspects from different teams. They decided to use two smaller tanks instead of one larger one in both locations, as some of the groups specified, since the smaller ones are easier to manage and take up less space. This was especially a concern at Kinsolving, since their garden and patio area is quite small.

In the end, the clients were pleased with the work the students submitted. Class evaluations from the students enthusiastically reviewed the opportunity to work on a real engineering assignment. The students were amazed to learn how that so much water can be collected through a rainwater system. They plan to use this practical knowledge in their professional careers, as well as in their own future homes. One student wrote:

As a future Environmental Engineer, I couldn't have imagined a project more suited to my interests. I never knew the potential that rainwater storage systems had, and now feel the desire to put tanks on the side of every building I see. Here in Austin, water is especially valuable, and now that I know how effective a water tank can be, I will bring it to the attention of every company I consult for in the future. Who knows? Maybe I'll even put a rainwater storage tank on my own house!
Thanks for a great year :)
Chandni Patel