Hydrology & Hydraulics

Mitchell/Shiloh/Conde Drainage & Roadway Improvements Town of Windsor, California Coastland | DCCM completed design and project management for three 36-foot wide arch culvert creek crossings, 1.5 miles of roadway extensions, reconstruction and overlays, new sidewalk, drainage improvements, storm drain creek outfalls, water and sewer main extensions, new travel lanes and bike lanes, electrical facilities, railroad warning installation, at-grade rail crossings, median island construction, lighting, traffic signals, water and reclaimed water systems, and landscaping.      The project included overseeing several subconsultants for various components of the design. Coordination with the NWPRR railroad, SMART, Caltrans, property owners, utility companies, and regulatory agencies (Fish and Wildlife, Corps of Engineers, Regional Water Quality Control Board) was essential. The construction cost is approximately $7.5 million.  

Lakeshore Drive Emergency Repair City of Clearlake, California Winter storms in late 2005 and early 2006 resulted in an embankment slide along Lakeshore Drive just north of San Joaquin Avenue. The embankment slide resulted in the loss of the paved shoulder in the outboard edge of the roadway. Coastland | DCCM completed design services for the City of Clearlake to repair the landslide. The federally funded Emergency Restoration (ER) project included widening the inside northbound lane by cutting into the existing embankment to create a uniform curve approximately 475 feet in length. The widening also included providing a drainage ditch along the uphill side of the road and an AC berm along the downhill side of the road to reduce surface water from migrating onto the downhill slope embankment. To further reduce the potential for future slipping of the roadway, launched soil nails were used to reinforce the slope. The installation of the launched soil nails incorporated a reinforced shotcrete cap and were inserted into existing soil masses by high-pressure air. In addition to design services, Coastland | DCCM provided bid support and construction design support services. The project also required extensive coordination with Caltrans to meet funding requirements.

FEMA/CALEMA Erosion Control Projects County of Napa, California Coastland | DCCM currently provides civil engineering services for the repair of several FEMA and State funded flood repair projects throughout Napa County. These projects include the design and construction of repairs to County roads and bridges that were damaged during severe rainstorms. The rainstorms saturated soil and flooded drainage channels which caused road slides and stream channel erosion at bridge structures. The design of the repairs follow FEMA funding guidelines and requirements including performing geotechnical evaluations, evaluating design alternatives, designing soldier pile retaining walls with tiebacks and reconstructing the damaged roadways. Improvements include stabilizing the slides, reconstructing the roadway to conform to the existing road in both width and structural section and addressing local surface and subsurface drainage. The projects Coastland | DCCM has designed to date include the following: Westgate Bridge over Milliken Creek Whitehall Lane FEMA Road Repair Diamond Mountain Roadway Repair 4700 Block Redwood Road Slide Repair 4800 Block Redwood Road Slide Repair, Phases 1 & 2 White Sulphur Springs Flood Repair (CalEMA) Coastland’s responsibilities include project management, designing the improvements, preparation of PS&E and construction administration. Coastland also completed the construction management and inspection services associated with these projects.

Talbot Avenue Storm Water Quality Project City of Santa Rosa, California Coastland | DCCM designed the Talbot Avenue Improvement Project to treat water runoff by employing bioretention tree well systems and hydromodification control systems. The tree well units are custom manufactured by Filterra Bioretention Systems, housing filter media in underground concretes containers. The media capture storm water pollutants, which are decomposed, volatilized and incorporated into the filter media biomass. Treated flows are routed to underdrains that discharge into the hydromodification systems. The storm water quality improvements were constructed as part of a larger capital project serving multiple objectives, including traffic calming, pedestrian enhancements and utility improvements. The entire project was completed in 2010 at a cost of approximately $2.3 million.  The project represents a notable collaboration of City of Santa Rosa staff, Caltrans, Sonoma County Transportation Authority, North Coast Regional Water Control Board, the contractor, and Coastland | DCCM’s design and construction management teams working together to protect the environment.  The Talbot Storm Water Quality Improvement Project was selected as the winner of Storm Water Solutions Top Storm Water & Erosion Control Project of 2010. The award recognizes innovative, challenging projects that address issues such as runoff treatment, water quality monitoring and flood control.