Storm water culverts are critical roadway safety assets which divert water from thoroughfares. In the next five years alone, more than $3.6 trillion must be invested in U.S. transportation infrastructure. Annually, DOTs install more than 12 million feet of storm water culverts and more than 1 million existing culverts require repair. Aging culverts pose several risks because unexpected failures can cause traffic disruption, environmental and property damages, and loss of life. Aged culverts are increasingly being rehabilitated using in-situ methods, where advanced polymeric materials such as spray-on coatings and cured-in-place pipe (CIPP) lining processes are created and installed in the field. CIPP is considered the most widely used trenchless pipeline rehabilitation method in the world, and has become a common method for rehabilitating storm water culverts maintained by DOTs. In-situ methods are attractive because they avoid open-trench excavation, traffic disruption, and work zone safety issues. Today, DOTs face two major culvert rehabilitation challenges due to the absence of data. First, studies by a subset of DOTs have discovered that the installation of advanced polymeric materials such as spray-on coatings and cured-in-place lining (CIPP) processes can release toxic chemicals into the water conveyed by the culverts. Fish kills from CIPP projects have been documented in the U.S. and Canada. Numerous additional anecdotal accounts from the U.S and other countries have been reported regarding adverse effects to the environment and wastewater facilities. While several DOTs have moved to upgrade their specifications, the performance of individual specification construction controls remains unknown. DOTs do not have the information needed to select from a field-validated set of culvert rehabilitation construction controls. Moreover, DOTs cannot strategically identify construction controls for culvert rehabilitation technologies that enter the marketplace in the future. Second, DOTs lack information on the degree that chemical leaching affects polymeric material long-term structural performance. Recent studies have shown some of the chemicals released into the environment by culvert rehabilitation polymeric materials are product ingredients intended to promote material strength and durability. Evidence from other polymeric material - water infrastructure applications clearly demonstrates that polymer composition is largely responsible for material longevity. The impact of losing these compounds on the long-term performance of culvert rehabilitation materials remains unknown. DOTs need information on how newly installed polymeric materials age in storm water applications, particularly when some degree of chemical leaching occurs.

The primary project objectives are to determine the following: (1) The scope of the problem across DOTs (i.e., the extent of use of these technologies and the scale of their impacts to water quality); (2)The effectiveness of existing construction specifications at minimizing contaminant release from rehabilitated culverts; and (3) The degree to which the structural integrity and longevity of rehabilitated culverts are compromised by chemical leaching. Results of this project will enable DOTs to make informed decisions with regard to culvert rehabilitation selection and specification development.

(1) Survey state DOTs to determine (1) proportion of projects using technologies with polymer components (i.e., CIPP, coatings, liners, polymer-enhanced materials) and (2) document any construction specifications in place for these methods. (2) Conduct water quality testing from culvert rehabilitation sites in multiple states to determine implications to the aquatic environment and the effectiveness of any existing specifications. (3) Determine the relationship between chemical leaching, decreased liner structural integrity, and longevity through laboratory accelerated aging tests and analyses of exhumed materials from the field. (4) Use the findings from this study to provide DOTs two forms of guidance: (1) a final report that will include recommended construction specifications to minimize environmental impacts and maximize performance, and (2) a hands-on training workshop about current and emerging culvert rehabilitation technologies, specification considerations, and factors to consider for environmental and structural performance.

Recommended funding $560000; Performance Period 3 years; Suggested contribution per partner: $35,000/yr for three years