brownsville and sodom dam removals

student research assistants - kelly kibler, cara walter, denise elston

link to project website

The removal of two dams, the Brownsville Dam (143' wide, 4' high), reconstructed in the 1960's and managed by the Calapooia Watershed Council (CWC) and the Sodom Dam (wide, high), constructed in 1957 and managed by Oregon Parks and Recreation, are scheduled along the Calapooia River Basin. Both of the dams are in need of structural repair and act as barriers to migrating salmon: Steelhead and spring Chinook are both ESA listed in this basin. Steelhead population is in the range of 350-500 fish, which the Chinook number fewer than 30.  Habitat in the upper watershed is capable of supporting upwards of 1100 steelhead and 650 chinook. 

chiloquin dam removals

Chiloquin Dam is located near the City of Chiloquin in Klamath County, south-central Oregon, approximately 30 miles north of Klamath Falls.  This 21’ high, 220’ long structure is positioned at River Mile (RM) 0.87 on the Sprague River, a short distance upstream of the confluence with the Williamson River.  Approximately 10 miles downstream of their confluence, the Williamson and Sprague rivers empty into Upper Klamath Lake, contributing nearly half of the lake's total annual water supply (NANFA 2004).  In this context, the Chiloquin Dam is positioned to substantially influence ongoing restoration activities aimed to improve sucker fitness and survival in Upper Klamath Lake. 

Constructed in 1914, Chiloquin Dam has served for nearly 100 years as a gravity diversion, supplying irrigation water to the Modoc Point Irrigation District (MPID), the dam’s current owner.  The MPID currently diverts up to 60 cfs for irrigation from May 1 through September 30 of each year and will continue to do so through a pumping station to be developed prior to dam removal.

Three fish species have historically occurred or currently occur near the Chiloquin Dam site and are listed as federal and/or state threatened and endangered (Reclamation 2003, FWS 2004, ODFW 2004). The shortnose sucker (Chasmistes brevirostris), Lost River sucker (Deltistes luxatus), bull trout (Salvelinus confluentus) are all federally listed under ESA, with the former two designated endangered and the latter designated threatened.  Because the dam has only one functional fish ladder (Reclamation 2003), it acts as a major barrier to these fish as they migrate to historical spawning and rearing grounds in the upper Sprague River Watershed.  The dam is particularly prohibitive to migrating fish during the summer (July through November) when stream flow drops to between 100 and 400 cfs, well below the mean annual discharge (588 cfs) at Chiloquin Dam (Reclamation 2003). 

Removal of Chiloquin Dam will allow unrestricted spawning access for endangered suckers, as well as other aquatic species (Pacific Lampreys, sculpins, Redband Trout), to approximately 80 miles of habitat in the Sprague River above Chiloquin Dam (BIA 2005).  The reconnection of the fish to these habitats is expected to increase access to cover to escape stress, competition, and predation as well as to create new and increased opportunities to spawn, rear, and feed (BIA 2005).