Design and Permitting the Des Moines Marina Improvements

In order to replace aging infrastructure and support a shift in marine tourism towards larger boats, the Des Moines Marina redesigned and upgraded their facility. In designing the replacement for their aging timber bulkhead, the marina made the unusual decision to convert land into water in the project as slip spaces had become more desirable than parking spaces since the construction of the marina. However, as design progressed, it became evident that only portions of the bulkhead could be replaced behind the existing one. The design engineers worked with the permit team to manage geotechnical challenges on the project and to take advantage of potentially environmentally-beneficial aspects of the proposal in regulatory negotiations. The timing of the project was driven mainly by the increasing need for infrastructure repairs throughout the marina. The timber bulkhead, which was supported with a tieback system, was originally constructed in 1969 as part of the development of the marina. In 1988, and again in 1998 the bulkhead was repaired with additional rock placed at the toe of the wall. Over time, the bulkhead continued to degrade. In 2000, the bulkhead was estimated to be at 60 percent of its original capacity. Other marina infrastructure required replacement as well, including gangways, floats, utilities, the travel-lift pier, and the promenade. Permitting the project was not a straightforward task. The proposed redesign was complicated by pollution from the on-site boatyard, the potential for affecting numerous endangered and threatened marine species in the area, and tribal coordination. Permitting tasks for federal and state agencies, and local/tribal jurisdiction coordination included: Rivers and Harbors Act Section 10, Clean Water Act Section 404, and Section 401 Permit Applications; Endangered Species Act Biological Evaluation (BE); Essential Fish Habitat Assessment (EFHA); State Hydraulic Project Approval (HPA); Spawning Survey; Preliminary Eelgrass and Macroalgae Survey; State Environmental Policy Act (SEPA) checklist; and a Shoreline Substantial Development Permit (SSDP) Application. Through the design process, the team was able to find ways to mitigate for project impacts by integrating features in the infrastructure improvements that provided habitat benefits. This paper presents the ways in which these features were incorporated to facilitate project permitting and still achieve all of the project goals for the marina.