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Small Dam Removal Effectiveness Monitoring
Introduction

Funding of Oregon dam removal restoration projects falls within the top 10 areas of OWEB restoration investments. Brownsville Dam on the Calapooia River, Marmot Dam on the Sandy River, Chiloquin Dam on the Sprague River, Savage Rapids Dam on the Rogue River, Sodom Dam on the Calapooia River have all been removed in the past ten years (updated 2016). These removals have placed Oregon in a position to support the evaluation of small dam removal projects. The Board therefore prioritized funding of effectiveness monitoring to document while improving the ability to predict ecosystem response of future dam removals.

Small Dam Removal Guide

OWEB is pleased to announce the availability of this handy guide for people managing the removal of small dams in their watersheds. Author Denise Hoffert-Hay shares valuable insights and useful permitting information based on her experience managing the 2007 removal of the Brownsville Dam in the Willamette Basin's Calapooia Watershed.

Because small dam removal in Oregon is relatively new and will likely change (especially permitting), the guide is posted here rather than printed. We intend to update it periodically as regulations change and as project managers send us comments for improvement. Plesae email and comments, photos, or links to: andrew.dutterer@oregon.gov.

Brownsville Dam Removal
  

The removal of the Brownsville Dam on the Calapooia River is expected to affect local hydrology, sedimentation processes (erosion, transport, and deposition), and the ecology of the Calapooia channel, floodplain, and riparian zone. This effectiveness monitoring strategy is designed to document the short-term effects of these removals, including the benefits and risks associated with the removal of Brownsville Dam, while improving the capability to predict ecosystem response related to dam removal. A study of the social and community influences and outcomes of dam removal at Brownsville Dam will be completed under another monitoring program.

Savage Rapids Dam Removal
 

The objective of this research is the documentation of physical and biological responses of the Rogue River to dam removal.  Presently, four dam removals are at some level of implementation. As a “medium” sized dam removal, the proposed monitoring strategy is critical as this removal represents an important learning opportunity. The monitoring approach is designed to engage local stakeholders in an assessment of river recovery while addressing important research questions of interest to the broader science community. The analyses and documentation will articulate and test procedures for reliability in predicting responses to dam removal, making tools more accessible for future dam removals. Thus, in combination with monitoring activities occurring at the Brownsville Dam removal site, this monitoring program will document the outcomes of a small and medium dam removal, as well as demonstrate, test, and document effectiveness monitoring procedures for future dam removals. This will occur through the development of a guidance document, including (1) sample monitoring plans, study designs, and data analysis approaches of systematic effectiveness monitoring; (2) detailed cost estimates (per-hours/year) and features of various methods for future monitoring planning; and (3) development and documentation of monitoring and prediction methods, such as estimating stored sediment volumes behind dams.

Marmot Dam Removal and Sediment Transport Monitoring
 

The ability to forecast channel change in response to dam removal is a critical component of the dam removal project decision-making process. Monitoring the changes in the Sandy River following the removal of Marmot Dam provides a unique opportunity to gather key data which will aid in the development of a model for sediment routing following a dam removal.  The project will also document the changes over time in the hydro-geomorphic form of the Sandy River as the Marmot Dam sediment moves through the system. The results will add to the regional understanding of dam removal projects.

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