Introduction

The U.S. Geological Survey (USGS) received a request from the Bureau of Reclamation (Reclamation) to provide monitoring and an evaluation of the effectiveness of habitat actions that Reclamation plans to implement in the Upper Columbia River basin, which includes the Methow River. This monitoring and evaluation program is to partially fulfill Reclamations part of the 2008 Biological Opinion for the Federal Columbia River Power System that includes a Reasonable and Prudent Alternative (RPA) to protect listed salmon and steelhead across their life cycle. The target species in the Methow River for this monitoring and restoration effort include Upper Columbia River (UCR) spring Chinook salmon (Oncorhynchus tshawytscha), UCR steelhead (O. mykiss), and bull trout (Salvelinus confluentus,), which are listed as threatened or endangered under the Endangered Species Act.

This report covers UCR activities performed by USGS personnel from March 2011 to November 2011. It involves collecting and analyzing data collected during pre-implementation (2008–2012) there will be a follow-up after actions are completed (2012–2014). The goal of Reclamation is to maximize the potential of habitat and improve proposed limiting factors affecting the middle Methow River subwatershed (Reclamation, 2010). The Middle Methow (M2) reach (river kilometer mile [rkm] 843.065 to 843.080) of the Methow River was selected as the treatment reach for this study based on possible stream restoration plans by Reclamation (fig. 1). The upper Methow River (rkm 843.094 and 843.080), Chewuch River, and the Methow River downstream of the Twisp River (rkm 843.065) are being sampled as reference and control reaches in this study (fig. 2). This report covers the third year in the pre-evaluation of the M2 reach and its side channels. Restoration of the M2 reach is scheduled for 2012, which is planned to be followed by a multi-year intensive post-evaluation period.

The intent of the summary of information provided in this report is to fulfill the objectives and tasks submitted in a statement of work to Reclamation in November 2010 (Connolly and Martens, 2011). The study design provides data by which to assess potential fish response to a Reclamation habitat restoration effort focused to improve juvenile salmonid rearing habitat in the M2, which runs between the towns of Winthrop and Twisp, Washington (fig. 1). The pre-treatment phase of the study is designed so that specific questions about the response of target fish species (spring Chinook salmon, steelhead, and bull trout) to the restoration actions can be addressed. Effectiveness is being determined by measuring fish productivity and habitat connectivity of the restoration reach and adjoining reaches, and their tributaries. The study includes sampling efforts directed to understand the relationships between stream habitat and the abundance of various fish species and to assess the response of the fish community. To complement these measurements, we will use models to predict response to treatment, and we will update the model with empirically derived data as these data become available. This modeling effort is expected to inform us of data gaps, sensitivity of key variables, and ability to detect response based on variability of the data.

The approach and actions taken or planned by Reclamation to modify off-channel habitat are largely untested as to their effectiveness to improve target fish species’ productivity and survival needs. Those documented strategies that identify both physical parameters and biological relationships and benefits have been identified (Reclamation, 2008). To assess biological performance, we plan to compare age structure, growth, and age at smolting between those fish that stay in natal areas versus those fish that move. To assess retention in, and movement from or into, the restoration reach, we have used a combination of within-reach and out-of-reach sampling. We are using passive integrated transponder (PIT) tags, a network of instream PIT tag interrogation systems, and smolt traps to assess differences in biological performance and the magnitude of retention in, and movement from and into, the restoration reach.

First posted May 31, 2012