Major Flooding Impacts Carlsbad and Eddy County
April 3, 2004

The Eddy County flood survey revealed that three different factors contributed to the record flooding in and near Carlsbad. Floodwaters from Rocky Arroyo Draw fed into the Pecos River north of Avalon Reservoir. This flow along with heavy rainfall from thunderstorms resulted in a required release of water from the Avalon Reservoir. Radar estimated rainfall totals of 3 to 4 inches fell near and west of Avalon Reservoir between 900 PM MST on April 3rd through 100 AM MST on Sunday, April 4th. Releases from the reservoir began near 800 PM MST on April 3rd, with a measured peak rate of 14,800 cfs (cubic-feet per second) at around 400 AM MDT Sunday morning. This release of water eliminated the potential danger of a dam failure, but resulted in the washout of Callaway Drive just downstream from the release point on Avalon Reservoir. The following pictures are of the main release point of Avalon Reservoir and the effects of the release on Callaway Drive.

aerial photograph of flooding at Lake Avalon
Figure 1. Avalon Reservoir

aerial photograph of flooding at Callaway Drive in Carlsbad
Figure 2. Pecos River washing our Callaway Drive

The second factor contributing to the record flooding was extremely high flow through the Dark Canyon Draw into downtown Carlsbad. Radar estimated rainfall of 1 to 3 inches fell over and southwest of Dark Canyon during the evening and overnight hours of Saturday April 3rd. This rainfall led to catastrophic flash flooding along the Dark Canyon Draw from southwest portions of Carlsbad into the downtown area. A wall of water moved down Dark Canyon Draw at approximately 1:30 AM MST Sunday morning. The pictures below show some of the effects of the flooding. The first picture shows a water tanker that flowed down Dark Canyon Draw, and eventually was pushed up against the Atchison Topeka and Santa Fe Railroad Bridge just east of Highway 285 bridge. The second picture shows the washout of Hidalgo Road at Dark Canyon Draw. The third picture shows the washout of Boyd Drive at Dark Canyon Draw.

aerial photograph of flooding through Dark Canyon Draw
Figure 3. Dark Canyon flowing across railroad bridge.
aerial photograph of flooding through Dark Canyon Draw
Figure 4. Dark Canyon Draw flowing across Hidalgo Road

aerial photograph of flooding through Dark Canyon Draw
Figure 5. Dark Canyon Draw washing out Boyd Drive.

The third factor that contributed to the flooding was the failure at several points of the CID (Carlsbad Irrigation District) canals. These CID channels, used primarily to irrigate areas alfalfa fields, began failing due to runoff from the 8-12 inches of rainfall over the three days crossing perpendicular to the CID channels. Erosion of the channels began occurring due to the high volume of water flowing over them. As the channels finally failed, water flowed into adjacent neighborhoods. The community hardest hit by this runoff was the La Huerta neighborhood in northeastern Carlsbad. The following picture shows the major points at which the CID canals were breached and allowed water to flow through the La Huerta neighborhood. As a result of this flooding, 6 to 12 inches of water was left standing throughout most of the La Huerta area with higher amounts at isolated points.

aerial photo of flooding in the La Huerta region of Carlsbad
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