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https://hdl.handle.net/11681/39003| Title: | Black Lake Ecosystem Restoration Technical Report |
| Authors: | United States. Army. Corps of Engineers. Alaska District. |
| Keywords: | Black Lake (Lake and Peninsula Borough; Alaska) Lake restoration Restoration ecology Sockeye salmon Environmental management Environmental protection |
| Publisher: | United States. Army. Corps of Engineers. Alaska District. |
| Abstract: | This report investigates the physical and biological conditions at Black Lake on the Alaska Peninsula in southwestern Alaska. Black Lake provides prime rearing habitat for sockeye salmon, a critical commercial and subsistence resource to the local population. Changes observed in Black Lake over the past several decades include reduced depths and volumes. There is concern that continued reductions in depth and volume would result in harmful and unrecoverable impacts to the salmon that utilize the habitat in Black Lake. Investigations conducted as part of this study have determined that the changes observed in Black Lake are in response to geomorphic changes in the river that drains it. While Black Lake may experience further reductions in volume, the risk does not appear imminent based on recent indications that Black Lake could be approaching a new state of equilibrium. Nevertheless, continued monitoring is recommended by periodically measuring the volume of Black Lake and elevation changes in the lake’s outlet and the upper reach of Black River below the lake outlet. Those measurements, coupled with an annual assessment of Chignik sockeye smolt production, would establish whether Black Lake is still degrading, and if so, the ensuing impact on system-wide sockeye production. The above measurements would also help determine whether future intervention may be warranted. Numerous structural measures were considered to alleviate the impacts of reduced depths and volumes in Black Lake to date; however, none are recommended for implementation at this time. |
| Description: | Technical Report |
| Rights: | Approved for Public Release; Distribution is Unlimited |
| URI: | https://hdl.handle.net/11681/39003 |
| Size: | 95 pages / 6.38 MB |
| Types of Materials: | PDF/A |
| Appears in Collections: | Environmental Documents |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| BlackLakeTechnicalReport_2012.pdf | 6.38 MB | Adobe PDF |  View/Open |