GLOBE students in Sunland Park, New Mexico study satellite images to decipher August 2006 flood damage

Students at Desert View Elementary School in Sunland Park, New Mexico have been involved in the GLOBE (Global Learning and Observations to Benefit the Environment) Fermilab Engaged Learning Program, and New Mexico Service Learning Program for several years. Land Cover change, especially those changes affecting watersheds, is part of GLOBE´s agenda. During an extreme precipitation event, August 1, 2006, the Sunland Park, New Mexico, Cuidad Juarez, Mexico and El Paso, Texas region experienced severe flooding as a result of torrential rains, and subsequent failure of an inadequately engineered municipal drainage system. A record 187 mm (7.5 in.) reportedly fell in three hours. In an effort to demonstrate to his students why this storm event created such havoc in the region, Albert Ortiz, a teacher at Desert View, decided to have his students use satellite imagery to investigate the problem. The students were asked to study the images to determine what effect land development, particularly in areas where major arroyos drain the mountain slopes, added to the flooding. Since no post flood images could be obtained the students were taken on a field trip to selected areas with copies of these images to analyze changes that had taken place as a result of flash flooding. The students first measured width of several major arroyos and compared it with what they saw on the pre-flood image. They found them to be at least four times wider. They determined the cross-sectional area of selected arroyos and estimated the amount of discharge coming from them during peak flow. In the field they elected to follow, and take measurements in the main arroyo leading from Franklin Mountain State Park, to where it entered the Rio Grande River. This park is located on the western flank of the mountain. As the students followed the arroyo out of the park down to where it passed under a bridge at Trans-Mountain Road and 1-10, about 9 km away, they could see on the satellite image that several ot- her arroyos converged with the one they were following. They again measured the arroyo at that location. After passing under the Interstate bridge, the drainage water from these arroyos is diverted into a channel that makes a 45 degree angle from a direct path to the river. The channel´s size and angle was completely inadequate to handle the volume of water flowing into it as a result of the heavy rain. A small housing development located next to the channel at Mowad St. was engulfed by mud and flood water from the overflowing channel and the houses were declared completely uninhabitable and condemned. The students visited the Mowad St. development where they saw condemned houses and piles of rubble where other houses had been bulldozed. They discussed how much of the destruction could have been prevented. By using satellite images, and comparing them with what they investigated on their field trip, the students were able to see how much change had taken place in their watershed, both from natural causes and by residential and industrial development on the mountain slopes. They also learned how technology can be used to address real life problems such as the one that overtook the Mowad St. subdivision.