ArcNews Online

Winter 2005/2006

E-mail to a Friend

Santa Ynez Valley, California, Union High School Students Map Town Water System with GIS and GPS

In September 2003, the Environmental and Spatial Technologies (EAST) class at Santa Ynez Valley Union High School, Santa Ynez, California, was contacted by Mike Loehr, who documented and helped represent Mission Santa InÚs when it was approved for National Historic Landmark District status in 1998. He asked the class about their ability to map the mission's water system using GPS and GIS technologies. This had never been done before and was a challenge as development is increasingly reaching out into the area.

"This is the best example of the use of historical research, geophysics, and archaeology to solve a particular problem that I have ever seen!"
—Dr. Robert Hoover, Professor Emeritus, California Polytechnic State University, San Luis Obispo

The high school students began by researching all that was known about the mission through their archives, databases, and other libraries. The student teams then used GPS units to map known aqueduct sites. The aqueduct was originally installed underground to supply water to this important and prosperous mission. Most of these known sites were rediscovered in 1980 when new homes and access roads were built. All known sites had an elevation of approximately 490 feet above sea level.

GIS expert team student leaders then began to extrapolate where the sites could be using Esri software and United States Geological Survey (USGS) topographic maps back in the classroom. Using ArcView for the first time, students were able to successfully plot points and use elevation data while learning the software. The biggest problem the students faced was all the development that occurred on or near Alamo Pintado Creek. It was commonly believed the creek was the source of water for the mission. It runs year round; is listed in old Spanish documents about the mission; and is the site of Chumash and, later, Santa Ynez Valley towns.

A previously unknown buried section of the aqueduct was recently discovered due to erosion causing a small arroyo to form. Pieces of the aqueduct were washed into the street, enabling students to discover where the aqueduct crossed Alamo Pintado Road based on where they found rock, mortar fragments, and tile. All these sites are on the 490–500-foot contour and were mapped using ArcView. Students also discovered fragmentary evidence, river rocks, mortar, and other debris caused by erosion at the base of this parcel of land.

Back in the EAST classroom, students Tim Manchester, Erin Gnekow, and Clay Garland, assisted by Erik Glendinning, a project member, used ArcView to draw a buffer delineating the 500-foot contour line overlaid onto current USGS topographic maps. Without this ability to see what was occurring, the students could not visualize the path and the eventual location of the dam.

Using this data and extrapolating a possible route based on elevation showed that all known sites fell on this route. The class then got permission to dig a small trench and found the aqueduct where they predicted it would be! Students were working at this time on the portion west of Alamo Pintado Road. The students, guided by teachers Chip Fenenga and Kim Merz, also began to collect reference information, including various journals, texts, photos, etchings, and interviews.

It concerned the participants that this 500-foot contour line, where the aqueduct ran, did not come near the only known source of water, Alamo Pintado Creek, until far upstream where no aqueduct features had been found. Development had occurred on the eastern portion of Alamo Pintado Road including both residential and commercial building. To investigate this further, the class obtained a copy of a 1905 USGS topographic map. This showed that almost 5,100 feet northeast from the mission, the 500-foot contour line ran through Alamo Pintado Creek. This would have allowed water to flow to both the mission using the underground aqueduct and a mill complex using gravity. "That was so cool, getting that map, as I could see the pieces falling together," notes Clay Garland, a junior at Santa Ynez Valley Union High School. "Suddenly, history made sense, and I could feel the connection to the past."

Essentially, the native Chumash under Spanish instruction built the aqueduct using river stones and mortar so the water could flow to the mission and be used for cooking, cleaning, and eventually irrigation.

After writing their report, the students were nominated and received the California Governor's Award for Historic Preservation from Governor Arnold Schwarzenegger. This is the first high school to earn this award.

To map the complete water system, the students needed to find the location of the dam. This mission was the only one in California for which a dam had not been located. The final piece of the award-winning project seemed lost in the passage of time. After the heavy 2004/2005 winter rains, the students began a second search for the original dam. "We wanted to finish the story we started last year," says Glendinning.

Six students, armed with GPS units and cameras, ventured into the creek bed in March 2005 near the Creekside housing development for another attempt to find the dam. Kenny Wilkens, Greg Bridgeman, and Tim Manchester first found the dam and brought back photos and a GPS location to the class. There, using ArcView, students Kelly Lyon and Clay Garland determined that the location matched their data and found out that Santa Barbara County owned the land so access would not be a problem.

"All the aqueduct pieces were between 500 and 520 feet in elevation," explains Lyon, "so we used ArcView generated contour lines and elevation to predict where the dam site was."

"You never expect to find it, but then there it was," says Manchester, who led the group of students, some media, school officials, and County Trust for Historic Preservation archaeologist Mike Imwalle to the dam site. What remains of the dam are a few low sections of cement and river rock, over which the Alamo Pintado spills, with an unknown portion of the dam lying buried beneath almost 200 years of sediment.

"You can't imagine how much work these kids put into this and the level of confidence they display in problem solving," notes Fenenga. "It is so hard to tell a great story, but students are peeling back 200 years of history and making it come back to life. What some people call results, we know are just beginnings."

For further information, contact instructor Chip Fenenga (e-mail: or visit

Contact Us | Privacy | Legal | Site Map