Central Coast APWA Honors Arroyo Grande Creek Project


Cannon is pleased to accept the California Central Coast Chapter APWA 2019 Project of the Year Award in recognition of the Arroyo Grande Creek Waterway Management Project.  

According to the award’s criteria, “The Central Coast Chapter APWA Public Works Project of the Year Award was established to promote excellence in the management and administration of public works projects by recognizing the alliance between the managing agency, the consulting engineer/architect, and the contractor who, working together, complete public works projects.” This award is recognizing teamwork and the successful products of those teams.  

The Arroyo Grande Creek Waterway Management Project, which is to be completed by the end of 2020, exemplifies the above description. To provide a seamless project outcome, the County, along with Cannon and Waterways Consulting, worked together to coordinate and secure funding for the project, gain appropriate permits, work with local and federal stakeholders, develop construction documents, and provide long-term management. These collaborative efforts between all parties balanced sensitive environmental considerations with protective measures to reduce potential flooding impacts on the landowners and residents who live within the reach of the watershed.  

In response to severe flooding, the Arroyo Grande Creek Watershed was initially constructed in 1961 by the USDA Soil Conservation Service and the Arroyo Grande Resource Conservation District. At this time, the project was funded with federal, state, and local funds, with the San Luis Obispo County Flood Control and Water Conservation District (District) in charge of operating and maintaining the area. The main features of the project were a levee system and trapezoidal channel that confined Arroyo Grande Creek from its confluence with Los Berros Creek downstream to the Pacific Ocean. However, after another major flooding event in 2001, the County of San Luis Obispo initiated their efforts toward redesigning the Creek. 

John Evans, Cannon’s Principal Civil Engineer on the project, stated that “the environmental restrictions were a major problem for the County because they didn’t allow for proper maintenance to the vegetation, which contributed to the flooding problem.” 

The County of San Luis Obispo engaged Waterways Consulting to develop a design basis for preliminary plans to enhance the channel capacity and to provide a management program to keep the channel clear in the future. Design for the Arroyo Grande Creek Channel Waterway Management Program incorporated levee modifications and armoring, floodwalls, vegetation management, sediment removal, habitat enhancement, and other improvements necessary to protect the nearby residents of Oceano. 

Modifications to the lower three-mile reach of Arroyo Grande Creek were needed to increase the capacity of the creek and enhance flood protection up to a 10-year storm event. Other environmental benefits included enhancement of water quality conditions and the addition of a sensitive species habitat. The County selected Cannon to provide design engineering to finalize the construction documents. The Cannon team, including subconsultants Waterways and Yeh and Associates, worked closely with professionals that had assisted in the County’s decade-long effort to create and determine the design basis in which the preliminary plans for Creek enhancements were developed.  

“This project was an exercise in patience and determination, mostly due to the permitting requirements. It was a competitive process,” stated Evans. “It feels good to be recognized, first by the County, and now by the APWA for our capable, experienced team. Finally, after 20 years, we’ve achieved an overall strategy for a project that we can maintain moving forward.”