P3.7
Chronic flooding of the Tanana River and Piledriver Slough near Salcha, Alaska: possible causes and solutions
Edward William Plumb, National Weather Service, Fairbanks, AK
Flooding of low-lying areas along the Tanana River and Piledriver Slough near Salcha, Alaska has been a recurring problem in recent years. Frequently high surface and ground water levels in the area have repeatedly flooded portions of the Old Richardson Highway and restricted access to residences bordering Piledriver Slough. The flooding has created a significant inconvenience and financial burden for local residents because high water has ripped out culverts, washed away roadways, and inundated private homes on numerous occasions.
This area has not only seen a noticeable increase in spring breakup and fall flooding, but has also been plagued with an unusual series of wintertime flood events. Record warm temperatures which prevailed across Alaska during the winter of 2002-2003 may be responsible for a prolonged episode of wintertime flooding in the Salcha area. A general temperature sequence of "freeze-thaw-freeze" early last winter caused river ice to break-up and form local ice jams, and then subsequent freezing temperatures likely preserved some of the ice jams - essentially creating ice dams. It is speculated that ice dams at least partially obstructed the main channels of the Tanana River and diverted a substantial amount of flow into the far eastern channel, which parallels the Old Richardson Highway. The higher frequency of flood events may simply be related to, or exacerbated by, the long-term channel migration of the Tanana River.
The threat of future flooding continues to pose a significant concern for residents, as well as local, state, and federal agencies because of the impact to area roads and private property. This talk will present a background of the recent flooding along the Tanana River and Piledriver Slough near Salcha, as well as address some of the possible causes and solutions for the prevention and mitigation of flooding in this area.
Poster Session 3, Hydrometeorology Posters (Including Orographic and Scale Issues) (Hall 4AB)
Thursday, 15 January 2004, 9:45 AM-11:00 AM, Hall 4AB
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