Drainage Design Manual - the City of San Luis Obispo

Step 2 - Develop and Screen Alternatives• Define Project Goals and ObjectivesIt is important to define the Goals and Objectives early on in the bank repair planning process asa tool to be used in formulating and screening alternatives. In particular Goals and Objectivesfor Habitat Protection, Restoration, and Enhancement need to be determined as part of possibleproject mitigation requirements. In general use of a vegetative or biotechnical approach shouldbe given highest consideration as this approach will result in most impacts to wetlands beingmitigated on site through inclusion of aquatic and habitat elements in the project design. Thedesign should also consider including additional adjacent area, such as top of bank planting, orupstream/downstream aquatic habitat enhancement through installation of channel boulders androot wads.Most projects should be multi-objective with property protection, bank protection, habitatenhancement, and water quality protection foremost. Common Goals and Objectives include:Affordability - what is the most cost effective solution, and what are the costs relative toother alternatives and benefits?Acceptability - what is acceptable to the property owner, environmental interest groups,neighbors, and local government in terms of biological and water quality impacts, loss ofproperty, appearance, and access and recreation issues.Permitting - the plans should be consistent with City and County policy and regulationsand should not conflict with state and federal regulations governing activities innavigable waters, wetlands, floodplains, endangered species habitat and ripariancorridors.Sustainability - the project should provide the risk and hazard reduction targeted for thedesign flow and shear forces at the site in terms of durability and maintenance needs.Generally a review and evaluation of design alternatives is required by most permitting agenciesto insure the least environmentally damaging, technically and economically feasible alternative isselected. Table 6-2 summarizes the screening criteria to be used for the various channel bankstabilization alternatives. This table, when completed and submitted by the project applicant, isintended to provide a ready reference and support to the recommendations made for the variouskinds of bank stabilization structures considered. The most environmentally sensitive andpractical solution should be chosen as the preferred stabilization plan.Alternatives should be developed and evaluated with the following questions in mind:The No Action AlternativeIf no action is taken can the fluvial system heal itself at this location in a reasonableamount of time without causing or contributing to other problems? Is there room for thechannel to meander with appropriate setbacks?SLO Creek Drainage Design Manual 62 February 2003