Editor's note: Jim Burnett's first career covered 30 years with the National Park Service. Now a writer (he's the author of the popular Hey Ranger books that chronicle the humorous side of life in the national parks), Jim provides the following report on flooding at Big Bend National Park.

Images of volunteers filling sandbags in a race against rising waters have unfortunately become commonplace this year, in locations from the Midwest to the Gulf Coast. You don't normally expect to see such scenes in the desert Southwest, but they were repeated last week in Big Bend National Park.

Heavy rains in northern Mexico and western Texas during the past several weeks have resulted in flooding along the Rio Grande, which forms the park's southern boundary for 118 miles. At risk are park facilities near the river, the entire wild population of an endangered species of fish, and historic resources—along with the upcoming visitor season in these lower elevation areas of the park, which normally runs from fall to spring.

Employees and volunteers filled sandbags last week to try to protect park and concessioner facilities at Rio Grande Village, in the park's southeastern corner. The area includes a 100-site developed campground (the largest in the park), a visitor center, picnic area and nature trail. Concession facilities include a 25-site RV campground, store, and gas station. Six National Park Service families and two concession employees and their families have been relocated.

Flood waters posed grave risks to the remaining wild population of the endangered Big Bend Gambusia, or Big Bend Mosquitofish (Gambusia Gaigei). The known range of this fish has shrunk to a single, spring-fed pond near Rio Grande Village—the smallest geographic range of any known vertebrate. Two-hundred of the fish have been captured, and 150 of these that are considered to have the purest genetic strain were to be transferred to a fish hatchery in Dexter, New Mexico. Once flood waters have receded, a determination will be made about returning the fish to their native habitat.

Cultural resources are also threatened by the rising waters, and historic adobe buildings at Rio Grande Village and Castolon were being sandbagged or bermed by park staff and volunteers.

At Rio Grande Village, where flood stage is 13.0 feet, the river crested on Sunday, September 21, at 24.78 feet. At 20 feet, flooding of the campground begins to occur, and at 25 feet, major flooding of the campground and store are a threat. Readings on the USGS gauge Monday morning stood at 24.38 feet, and the river is predicted to fall slowly during the rest of the week, although it is expected to remain above flood stage for the rest of the month.

Park spokesman David Elkowitz said this morning that the restrooms in the NPS campground at Rio Grande Village and the RV sites at that location had been flooded, but the store and visitor center had escaped damage.

At Castolon, upstream from Rio Grande Village, flood stage is 15.0 feet, and major flooding of Cottonwood Campground and area roads occurs when the river reaches 19.0 feet. The Rio Grande crested at 23.1 feet on Saturday, September 20, and had begun a slow fall to 22.21 feet Monday morning. The river is still expected to be above flood stage at the end of this week.

Any additional rainfall in this vast watershed over the next few weeks could have major impacts on this situation, but the other wild card is an extensive levee system upstream from the park, near the town of Presidio. The National Weather Service reported this morning that water was topping the levees at the southern end of the Presidio levee system. Any levee breaches or failures could cause dramatic changes to the currently forecast river levels.

The road to Rio Grande Village is closed from the Boquillas Road junction to Rio Grande Village, along with the River Road and the road from Castolon to Santa Elena Canyon. Rio Grande Village, the Santa Elena Canyon Trail, Cottonwood Campground, Rio Grande Village campgrounds, and Hot Springs Road are also closed. All other major visitor use areas in the park are open.

Visitors planning river trips or travel to the Rio Grande Village or Castolon areas of the park can obtain updated information by calling 432-477-1188, or by checking the park's Daily Report.