August 16, 2023

The replacement culvert and channel protection systems are being installed simultaneously. During week ending Friday, August 4, the inlet wall footing was framed and poured while downstream riprap and gabions were installed. The following week, framing began on the inlet header wall and wingwalls. The rains on the evening of Monday, August 7, took soil away from the site and filled the forms and gabion walls with silt, necessitating two days of cleanup and repair. By Thursday, August 10, the inlet header and wing walls were formed again and ready for concrete pour on Friday, August 11. 

The current rough estimate for the reopening of the road is October 2023. The road closures at Calle Nopal and the Siler Roundabout will remain in place until the repairs are fully completed. Please allow extra travel time if navigating around the detours and seek alternate routes whenever possible.

This is a complex project due to the location of the culvert collapse, which is in a major arroyo for the area and also on private property. With the reconstruction, we're addressing detailed structural and environmental considerations and the future needs of the roadway at the same time.

• Because the project crosses an arroyo, creating the design of the reconstructed road required a complex hydrological analysis to address seasonal storm water flows and other environmental factors.

• The road collapsed because it lacked the necessary structural elements for long-term stability and safety: namely, a header wall, outfall structure, and downstream armoring of the channel for the arroyo. We are not only constructing these essential structural elements – which means rebuilding the foundation of the roadway from the ground up – but also ensuring that the project will not need to be redone in the future when the West Alameda Capital Improvement project to widen the roadway is undertaken.

• The roadway also crosses private property at the site of the collapse, and the City only has easement along the existing roadway to access the site to rebuild.

This project is using accelerated methodology to reduce the timeline as much as possible. Steps to expedite the process include:

• The construction and design contractors were engaged the day the culvert failure occurred using emergency procurement procedures. 

• Design, which required complex hydrological analysis, was completed rapidly and the City Governing Body appropriated funds based on 70% design so that a purchase order could be issued as soon as 100% design documents were complete and the construction contractor provided an estimate of construction costs. The engineer also approved submittals (documents from vendors showing that materials meet the required specifications for items like the rebar, concrete, rip rap, reseeding mixtures, etc.) on the same day, a process which usually takes three or more days. 

• During construction, the team is quickly responding to identified field changes which are common with projects in arroyos. The City is also using an expedited process of tracking changes during construction rather than stopping for administration of change orders, and waiting until construction is complete to process one change order. This method saves weeks and even months on the usual construction process. 

I-95 was able to reopen because a temporary roadway was constructed over the failed bridge. The City investigated options for a temporary crossing at the site of the West Alameda culvert failure but determined that it was unfeasible due to the unique nature of the site and project:

Summer is the busy season for roadway construction and New Mexico has limited contractors who are qualified for such a large project. Our contractor is required to maintain a safe work environment, and people can only work safely for so many hours per day. The contractor is applying as many resources as they have available to West Alameda while maintaining safety and meeting all other contractual requirements on other projects. 

The culvert appeared to have failed because there was no header wall holding the culvert in place and there was no outfall structure or downstream armoring of the channel. Because of this, water leaving the culvert undercut the structure, which over the years caused erosion which led to the collapse. When Santa Fe County owned the road, they performed a road widening project during which they extended the culvert but did not install a header wall, outflow structure and downstream armoring.  

The road became a City road when the City annexed the adjacent land to the south of West Alameda in 2013. As part of an MOU with the County regarding roadways impacted by the annexation, the need for improvements to West Alameda drainage and roadway were identified.

The City has carried a project on the capital plan to reconstruct West Alameda roadway and drainage for at least three years, and in preparation for that project, completed the West Alameda Drainage Study in 2021. That study was utilized in the design of the repairs needed to fix the collapsed section of the roadway.

The purchase order for design was issued for $90K. The purchase order for construction was issued for $750,000. Since this project combines roadway and stormwater infrastructure improvements, the Stormwater Fund, funded by the stormwater fee on utility customers’ bills, will pay for a portion, and the construction is being funded by 0.25% GRT dedicated to infrastructure operations and improvements.

The replacement culvert is being designed and constructed to meet the future needs of the improved roadway to be built during the larger West Alameda Capital Improvement Project. The culvert will not need to be redone when the larger project is undertaken and the asphalt will be rebuilt to include bike lanes and sidewalks with the later project.