Water Resources Research Act Program

Details for Project ID 2006OR74B

Evaluating the phosphorus dynamics in response to restoring historic hydrology at reclaimed wetlands along Upper Klamath Lake, OR.

Institute: Oregon
Year Established: 2006 Start Date: 2006-02-15 End Date: 2007-02-14
Total Federal Funds: $14,999 Total Non-Federal Funds: $35,648

Principal Investigators: Desiree Tullos, Desiree Tullos

Project Summary: Upper Klamath Lake (Oregon; UKL) is hypereutrophic due to phosphorus (P) loading from both geologic and agricultural sources in the watershed. According to ODEQs TMDL analysis, it is elevated P levels that drive severe algal blooms causing pH and dissolved oxygen to often reach toxic levels for fish in the lake. Restoring historic lake-fringe wetlands to provide P sinks around the lake is accepted as a favorable means of reducing lake P levels and loading. However, the capacity of restoration wetlands to sequester P is uncertain because of highly organic soils in these areas that were drained and fertilized over the last century. Previous studies demonstrated that dramatic P releases can occur after these soils are reflooded presumably as a result of organic P mineralization. Our study will quantify changes in form and concentration of soil P as and after levees are breached and natural hydrology is restored to two reclaimed agricultural fields adjacent to UKL. We will also measure changes in soil and floodwater characteristics to better understand the mechanisms of P sequestration and release. Globally, results will: (1) contribute to a more thorough understanding of wetland phosphorous dynamics; and (2) target strategies to promote phosphorus sequestration in restoration wetlands. Locally, these results will expedite water quality improvements in Upper Klamath Lake by providing a foundation to develop management strategies that sequester P in restored wetlands adjacent to UKL.