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Constraints, Criteria, & Standards

CONSTRAINTS

Several constraints must be considered when developing a streambank stabilization plan for Cripple Creek. These constraints limit the range of feasible solutions and ensure that the selected design aligns with the priorities of the United States Forest Service (USFS). The identified constraints include preservation of stream planform, intended land use, bank protection on both sides, budget limitation, and protection of the candy darter and other sensitive species.

PRESERVATION OF STREAM PLANFORM

The USFS requires that the existing planform of Cripple Creek be maintained throughout the project. This constraint prevents major channel realignments or alterations to the creek’s meander geometry. In other words, all stabilization measures must be designed to avoid widening the channel or modifying natural curvature. Preserving the stream planform helps to ensures long-term channel stability and prevents unintended impacts on upstream or downstream reaches.

CRITERIA

To compare potential solutions, certain criteria were chosen and assigned weights based on their perceived importance to the USFS. The chosen criteria are the degree of bank stabilization, ecological benefit, maintenance, durability/time span, cost, and aesthetics.

BANK STABILIZATION

Bank stabilization was included as a criterion because preventing further erosion is the primary objective of this project to maintain the Eagle Bend Hay Pasture. Evaluating how effectively each solution resists erosion and protects vulnerable banks ensures that the selected approach directly addresses the erosion issue at Cripple Creek. 

STANDARDS

Natural Resources Conservation Service (NRCS) US Department of Agriculture (USDA) National Engineering Handbook (NEH) Part 654 – Stream Restoration Design (United States Department of Agriculture, 2007; see Technology Review in Sources section on website): · Informs how designers can achieve a balance of management and engineering techniques based on the channel, and what the objectives and goals of the restoration plan · Contains technical supplemental information on stream classification techniques, bankfull discharge, scour calculations, and grade stabilization techniques

Natural Resources Conservation Service Stream Restoration Design Field Guide (“Stream Restoration Design Field Guide,” 2009; see Technology Review in Sources section on website): · Describes the overall procedure of conducting a stream restoration project, starting from work done before field work, to the design criteria and implementation of certain techniques · Presents guidance on different stream restoration methods that include research, case studies, and planning tools based on the design approach

United States (U.S.) Department of Agriculture (USDA), the U.S. Department of Interior, U.S. Forest Service, and Bureau of Land Management (BLM) NSAEC TN-102.5 September 2020 Guidance for Stream Restoration (Yochum & Reynolds, 2020; see Technology Review in Sources section on website): · Outlines the overall stream restoration process and provides further specification on design approaches, analyses, and restoration features that can be implemented in streams · Provides specifications on restoration features such as vegetation, large wood structures, and bank stabilization structures

US Department of the Interior Bank Stabilization Design Guidelines (Martin, 2015; see Technology Review in Sources section on website): · Focuses on specific bank stabilization designs, such as vegetation, large woody debris, and riprap, and the characteristics and factors to take into consideration for each design · Highlights different types of scour, measures to prevent scour, the methods for scour assessment, and the formulas used to calculate scour

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