Background

Upper Klamath Lake and adjacent Agency Lake in southern Oregon (fig. 1) experience episodes of poor water quality during algal blooms and periods of algal die off that may contribute to fish kills in the lakes and downstream reaches of the Klamath River in northern California. Scientists suspect that increased nutrients draining into the lakes as well as changes associated with loss of wetland habitat around the lakes contribute to such blooms. In an effort to reduce nutrient loading into Agency and Upper Klamath Lakes, property owners are initiating restoration efforts, including wetland restoration, and are in need of scientific data and information to guide these efforts. The Bureau of Land Management (BLM) recently acquired a 3,200 acre parcel of former wetland--the Wood River Wetland--located adjacent to Agency Lake (fig. 2). The BLM has asked the USGS to develop and implement a monitoring strategy that will assist them with evaluating the adaptive management of the wetland to achieve the goal of optimizing for water quality, water yield, and wildlife habitat.

Objectives

The objectives of the first year (Phase I) of the study are to:

• Characterize the spatial and temporal water-quality and habitat conditions within the Wood River Wetland at various states of inundation, including water depth, light penetration, basic field measurements (dissolved oxygen concentration, pH, temperature, conductance, and redox potential), turbidity, nutrients (nitrogen and phosphorus) in water and soil pore water, and dissolved organic carbon.
• Develop a preliminary water budget for the wetland, including measuring or estimating the inputs (precipitation, ground water, and direct and subsurface inflows from the Wood River, Sevenmile Canal, and neighboring properties) and outputs (water pumped to Wood River and Sevenmile Canal and evapotranspiration).
• Develop a preliminary nutrient budget for the Wood River Wetland to begin to understand how the wetland is affecting water quality and quantity.
• Develop a work plan for Phase II based on findings from Phase I.

The objectives of subsequent years (Phase II) are to:

• Continue refined network of data collection based on Phase I results for an additional period of 2 years followed by a year of data analysis, interpretation, and report preparation.
• Evaluate possible management options that enhance water quality, water storage capacity, and wildlife habitat within the Wood River Wetland.
• Examine how wetland conditions (pH and dissolved oxygen levels, for example) affect processes such as nutrient uptake by plants (emergent vegetation, macrophytes, and algae), nutrient releases from sediments, denitrification, and methylation of mercury.
• Summarize the findings from Phases I and II in an interpretive report.

Relevance and Benefits

This study will begin to examine the relationships among water level, vegetation types, habitat, and water-quality conditions in a newly restored wetland area. More specifically, this study will first characterize the spatial and temporal water-quality conditions, and then evaluate how various management scenarios (timing, magnitude, and source of water inputs and outputs, for example) affect water quality, water quantity, and wildlife habitat in the Wood River Wetland. Results from this study have high transferability to other wetland restoration efforts currently underway or planned in the basin. These include properties owned or managed by the Bureau of Reclamation, U.S. Fish & Wildlife Service, and The Nature Conservancy. It is expected that these organizations will use information derived from the study to assist in the design and monitoring of adaptive management of restoration activities associated with their wetlands. The successful implementation of adaptive management for these areas could help to maximize the beneficial use of the wetlands to help mitigate some of the water quality, water quantity, and habitat problems now occurring in Upper Klamath Lake and the Klamath Basin. A workshop focused on wetland restoration in the region also is planned during the second year of the study, to share, evaluate, and compare existing data among the various stakeholders, and to draw on local expertise to help guide activities during subsequent years of the study.

Approach

During the first year of the study, habitat (including water depth and light penetration) and water-quality conditions (nitrogen, phosphorus, dissolved organic carbon, chlorophyll a, major ions, and dissolved oxygen concentrations, turbidity, water temperature, conductance, and pH) will be characterized in the water column (mid-depth and, if stratified with respect to dissolved oxygen, near the sediment-water interface) at several sites colocated with permanent vegetation plots currently under investigation by the BLM (table 1). Water chemistry (concentrations of nitrogen, phosphorus, major ions, and dissolved organic carbon) also will be measured in soil pore water at a subset of these sites (table 2). Major ion concentrations will be used to construct trilinear plots for source-water delineation within the wetland.

Table 2. Water-quality samples to be collected during Phase I