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Boise River Enhancement Plan

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Boise River Enhancement Plan Boise River Enhancement Plan Boise River Enhancement Network Table of Contents The Boise River P.1-11 “We are a network of people Part 1 of this plan describes the background and setting of the river, the current need for cooperative planning, that live, work and play in the the vision for the river, and the process through which this plan was created. Boise River watershed dedicated The plan is designed to convey important and complex to promoting the ecological concepts through simple text and visual aids and therefore is not filled with source information and is not enhancement of the river” highly technical. Essential Features P.12-29 Boise River Enhancement Plan Part 2 is divided into four major ecological subject Prefered Citation: areas identified as critical ecosystem components for enhancement of the river: Geomorphology, Fisheries and Boise River Enhacement Network (BREN). 2015. Lower Boise River Enhacment Plan. Aquatic Habitat, Wetland and Riparian Habitat and Water Boise, Idaho Quality. Prepared for: Each section includes a narrative, clearly identified key Bureau of Reclamation issues within the subject area, and the most appropriate United States Department of the Interior and effective enhancement opportunities identified PO Box 25007 through the planning process. Denver, Colorado 80225-007 Prepared by: Entity Entity Number Road Road Realizing the Vision P.30-36 Boise, Idaho 83702 Part 3 addresses how the enhancement vison can be 555.555.5555 realized through summarizing past and current efforts within the watershed, examples from other watersheds, Disclaimer: Any electronic form, facsimile or hard and identifying which types of projects bring the greatest copy of the original document (email, text, table, benefits to multiple ecological subject areas. The plan and/or figure), if provided, and any attachments are seeks to identify how, what and where enhancement can only a copy of the original document. The original be achieved to bring the most effective benefits to the document is stored by Boise River Enhancement river. Network. Copyright© 2015 by Boise River Enhancement Network. All rights reserved. Cover photo: Credit; Boise River PART INTRODUCTION1 BOISE RIVER Why is this Plan Needed? At an October 2011 Boise River Workshop, over 120 participants identified the most important next step to enhance the Boise River; “Continue this group and develop a plan.” In early 2011, interested local stakeholders The workshop titled ”From Vision to Reality,” Following the workshop, a group of came together to plan a workshop on brought 106 of the area’s practitioners, interested organizations came together to environmental enhancement opportunities on experts, academics, decision makers, and form the Boise River Enhancement Network the Lower Boise River (LBR). All interested active citizens together for a substantive (BREN). This group received a grant from individuals and organizations were welcome discussion about the challenges and the Bureau of Reclamation’s WaterSmart to participate to foster an open and inclusive opportunities for environmental enhancement program to establish a watershed group and planning process. An Organizing Committee of the LBR. The results of the workshop, as write a watershed enhancement plan. BREN that included non-profit and for profit staff, measured from breakout session input and then used the results of the workshop to volunteers and agency representatives an online survey, identified key enhancement design a process and to identify key subject agreed on the goal of the workshop, “To goals and interests, challenges to areas on which to focus the effort. This plan increase opportunities for public and private enhancement, approaches to enhancement, is a result of these efforts to provide the ecosystem enhancement of the Lower Boise and key next steps. Participants identified essential next step in the enhancement of the River by establishing networks, building that the most important next step to enhance LBR. knowledge, envisioning possibilities and the Lower Boise River was to “Continue this tackling challenges.” group and develop a plan.” Approaches to Restoration Please rate the following approaches to restoration/enhancement on the Lower Boise River (Preferred, Acceptable, Of Limited Use, Unacceptable). PERCENT OF RESPONSES 70% 19% 19% 17% Preferred Preferred Preferred Preferred 19% 57% 46% 44% Acceptable Acceptable Acceptable Acceptable 17% 3% 2% 5% 8% Unacceptable Unacceptable Unacceptable Of limited use 2% 44% Unacceptable 21% 33% 33% Of limited Of limited Of limited use use use Watershed-scale, integrated plan Actions funded through existing Efforts mandated as mitigation for Opportunistic actions determined by with guided restoration efforts federal agency programs activities realted impacts landowner interests and desires | 1 Reach 1 Sinuosity CONDITIONTARGET CONDITIONTARGET Meander Width/Depth TARGET TARGET CONDITION CONDITION Belt Width Ratio POOR POOR CONDITION CONDITION 1 CONDITIONTARGET TARGET TARGET TARGET CONDITION Essential Feature CONDITION CONDITION POOR Floodplain CONDITION Embed- Example of Reach Example of Reach Width dedness in Poor Condition Meeting Target Condtion Reach 2 Sinuosity Bank Bed Composition Armoring Meander Width/Depth TARGET Belt Width Ratio CONDITION In-Channel CONDITIONTARGET Structure TARGET CONDITION POOR Floodplain Embed- Geomorpholgy CONDITION Width dedness Reach 3 Boise River Enhancement Plan Sinuosity Meander Width/Depth Belt Width Ratio Bank Bed CONDITIONTARGET Composition Armoring TARGET The LBR has been transformed from a Current channel capacity ranges between 3,500 In-Channel CONDITION TARGET Structure CONDITION meandering, braided gravel bed river that supported cfs and 10,000 cfs, although channel capacity POOR Floodplain CONDITION Embed- large runs of salmon to a channelized, regulated varies in time and space due to changing conditions. Width dedness Reach 4 urban and agricultural river that provides flood However, flood damage increases drastically above Sinuosity control, irrigation water conveyance and recreational 6,500 cfs. Prior to channelization, high flows would Meander Width/Depth Bank Bed Belt Width Ratio Composition Armoring CONDITIONTARGET opportunities to residents of the Treasure Valley. spread across the historically wide floodplain. Over TARGET In-Channel CONDITION the years, levees have been built and enlarged Structure TARGET Extensive alterations to the floodplain and CONDITION by individual land owners, cities, counties, and POOR Floodplain CONDITION Embed- hydrograph have resulted in a large suite of Width dedness local flood districts, many of which are unstable. Reach 5 geomorphic changes to this alluvial river system. Levees surrounding old gravel pits that now serve Sinuosity These changes include a floodplain that has Meander Width/Depth as ornamental ponds with little habitat value are Belt Width Ratio Bank Bed been drastically narrowed and disconnected CONDITIONTARGET Composition Armoring considered to be flood hazards TARGET In-Channel CONDITION from the current hydrology, Structure as they may increase flood risk TARGET CONDITION a hyporheic zone (where the POOR and result in “pit capture,” which Floodplain CONDITION Embed- local groundwater table and Width dedness can alter the river channel. Large Reach 6 surface water are interacting) snags, vegetation and debris Sinuosity that has been significantly Meander Width/Depth are removed from sections of Bank Bed Belt Width Ratio Composition Armoring CONDITIONTARGET reduced, channel substrate TARGET the river for recreation safety In-Channel CONDITION that has become armored and Structure and flood control reasons. TARGET CONDITION embedded, instream habitat POOR As a result of historic levee Floodplain CONDITION Embed- that has been simplified and Geomorphic Character of River Width dedness Braided/Complex Channelized/Regulated construction and current Reaches sloughs and side channels River Channel River Channel maintenance practices, the Target conditions considered existing that have been reduced. The hydrology but not necessarily development. highly narrowed river channel Bank Bed Given existing hydrology and other Composition Armoring dramatic anthropogenic induced changes to the TARGET lacks roughness elements and in-stream complexity existing geomorphic conditions, targets In-Channel CONDITION hydrology and floodplain have created a geomorphic that historically provided habitat for fish and other were identified representing what could Structure environment that is not aligned with the current reasonably be expected to occur over the aquatic organisms. The current channel form results long-term given a best-case scenario. The goal would be to work toward those hydrology, resulting in impacts to several critical in velocities that preclude refuge for salmonids targets systematically and opportunistically when and where possible. ecosystem processes. Although there are pervasive in many locations during the spring and summer The targets should be used to aim projects in the most appropriate direction, but conditions that affect the entire LBR, each reach should not be used as objectives. The expectation should be to move closer toward and create an abundance of shallow pool or glide targets not necessarily to meet targets across the board (which may never be 100% and site has its own specific suite of conditions that habitat in the late fall, winter and early spring. achievable). (Data From Richardson and Guulinger 2015) need to be evaluated
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